From 56fc494bdcba35d74da27e1d34dbb6db6fa7bd67 Mon Sep 17 00:00:00 2001
From: Greg Kurz <groug@kaod.org>
Date: Sun, 26 Feb 2017 23:41:40 +0100
Subject: 9pfs: local: move xattr security ops to 9p-xattr.c

These functions are always called indirectly. It really doesn't make sense
for them to sit in a header file.

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 hw/9pfs/9p-xattr.c | 61 +++++++++++++++++++++++++++++++++++++++++
 hw/9pfs/9p-xattr.h | 80 ++++++++++--------------------------------------------
 2 files changed, 75 insertions(+), 66 deletions(-)

(limited to 'hw')

diff --git a/hw/9pfs/9p-xattr.c b/hw/9pfs/9p-xattr.c
index 5d8595e..19a2daf 100644
--- a/hw/9pfs/9p-xattr.c
+++ b/hw/9pfs/9p-xattr.c
@@ -143,6 +143,67 @@ int v9fs_remove_xattr(FsContext *ctx,
 
 }
 
+ssize_t pt_getxattr(FsContext *ctx, const char *path, const char *name,
+                    void *value, size_t size)
+{
+    char *buffer;
+    ssize_t ret;
+
+    buffer = rpath(ctx, path);
+    ret = lgetxattr(buffer, name, value, size);
+    g_free(buffer);
+    return ret;
+}
+
+int pt_setxattr(FsContext *ctx, const char *path, const char *name, void *value,
+                size_t size, int flags)
+{
+    char *buffer;
+    int ret;
+
+    buffer = rpath(ctx, path);
+    ret = lsetxattr(buffer, name, value, size, flags);
+    g_free(buffer);
+    return ret;
+}
+
+int pt_removexattr(FsContext *ctx, const char *path, const char *name)
+{
+    char *buffer;
+    int ret;
+
+    buffer = rpath(ctx, path);
+    ret = lremovexattr(path, name);
+    g_free(buffer);
+    return ret;
+}
+
+ssize_t notsup_getxattr(FsContext *ctx, const char *path, const char *name,
+                        void *value, size_t size)
+{
+    errno = ENOTSUP;
+    return -1;
+}
+
+int notsup_setxattr(FsContext *ctx, const char *path, const char *name,
+                    void *value, size_t size, int flags)
+{
+    errno = ENOTSUP;
+    return -1;
+}
+
+ssize_t notsup_listxattr(FsContext *ctx, const char *path, char *name,
+                         void *value, size_t size)
+{
+    return 0;
+}
+
+int notsup_removexattr(FsContext *ctx, const char *path, const char *name)
+{
+    errno = ENOTSUP;
+    return -1;
+}
+
 XattrOperations *mapped_xattr_ops[] = {
     &mapped_user_xattr,
     &mapped_pacl_xattr,
diff --git a/hw/9pfs/9p-xattr.h b/hw/9pfs/9p-xattr.h
index a853ea6..3f43f51 100644
--- a/hw/9pfs/9p-xattr.h
+++ b/hw/9pfs/9p-xattr.h
@@ -49,73 +49,21 @@ ssize_t v9fs_list_xattr(FsContext *ctx, const char *path, void *value,
 int v9fs_set_xattr(FsContext *ctx, const char *path, const char *name,
                           void *value, size_t size, int flags);
 int v9fs_remove_xattr(FsContext *ctx, const char *path, const char *name);
+
 ssize_t pt_listxattr(FsContext *ctx, const char *path, char *name, void *value,
                      size_t size);
-
-static inline ssize_t pt_getxattr(FsContext *ctx, const char *path,
-                                  const char *name, void *value, size_t size)
-{
-    char *buffer;
-    ssize_t ret;
-
-    buffer = rpath(ctx, path);
-    ret = lgetxattr(buffer, name, value, size);
-    g_free(buffer);
-    return ret;
-}
-
-static inline int pt_setxattr(FsContext *ctx, const char *path,
-                              const char *name, void *value,
-                              size_t size, int flags)
-{
-    char *buffer;
-    int ret;
-
-    buffer = rpath(ctx, path);
-    ret = lsetxattr(buffer, name, value, size, flags);
-    g_free(buffer);
-    return ret;
-}
-
-static inline int pt_removexattr(FsContext *ctx,
-                                 const char *path, const char *name)
-{
-    char *buffer;
-    int ret;
-
-    buffer = rpath(ctx, path);
-    ret = lremovexattr(path, name);
-    g_free(buffer);
-    return ret;
-}
-
-static inline ssize_t notsup_getxattr(FsContext *ctx, const char *path,
-                                      const char *name, void *value,
-                                      size_t size)
-{
-    errno = ENOTSUP;
-    return -1;
-}
-
-static inline int notsup_setxattr(FsContext *ctx, const char *path,
-                                  const char *name, void *value,
-                                  size_t size, int flags)
-{
-    errno = ENOTSUP;
-    return -1;
-}
-
-static inline ssize_t notsup_listxattr(FsContext *ctx, const char *path,
-                                       char *name, void *value, size_t size)
-{
-    return 0;
-}
-
-static inline int notsup_removexattr(FsContext *ctx,
-                                     const char *path, const char *name)
-{
-    errno = ENOTSUP;
-    return -1;
-}
+ssize_t pt_getxattr(FsContext *ctx, const char *path, const char *name,
+                    void *value, size_t size);
+int pt_setxattr(FsContext *ctx, const char *path, const char *name, void *value,
+                size_t size, int flags);
+int pt_removexattr(FsContext *ctx, const char *path, const char *name);
+
+ssize_t notsup_getxattr(FsContext *ctx, const char *path, const char *name,
+                        void *value, size_t size);
+int notsup_setxattr(FsContext *ctx, const char *path, const char *name,
+                    void *value, size_t size, int flags);
+ssize_t notsup_listxattr(FsContext *ctx, const char *path, char *name,
+                         void *value, size_t size);
+int notsup_removexattr(FsContext *ctx, const char *path, const char *name);
 
 #endif
-- 
cgit v1.1


From 00c90bd1c2ff6aabb9ca948a254ba044a403e399 Mon Sep 17 00:00:00 2001
From: Greg Kurz <groug@kaod.org>
Date: Sun, 26 Feb 2017 23:41:48 +0100
Subject: 9pfs: remove side-effects in local_init()

If this function fails, it should not modify *ctx.

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 hw/9pfs/9p-local.c | 37 +++++++++++++++++++------------------
 1 file changed, 19 insertions(+), 18 deletions(-)

(limited to 'hw')

diff --git a/hw/9pfs/9p-local.c b/hw/9pfs/9p-local.c
index 7de07e1..4a8e628 100644
--- a/hw/9pfs/9p-local.c
+++ b/hw/9pfs/9p-local.c
@@ -1168,9 +1168,25 @@ static int local_ioc_getversion(FsContext *ctx, V9fsPath *path,
 
 static int local_init(FsContext *ctx)
 {
-    int err = 0;
     struct statfs stbuf;
 
+#ifdef FS_IOC_GETVERSION
+    /*
+     * use ioc_getversion only if the ioctl is definied
+     */
+    if (statfs(ctx->fs_root, &stbuf) < 0) {
+        return -1;
+    }
+    switch (stbuf.f_type) {
+    case EXT2_SUPER_MAGIC:
+    case BTRFS_SUPER_MAGIC:
+    case REISERFS_SUPER_MAGIC:
+    case XFS_SUPER_MAGIC:
+        ctx->exops.get_st_gen = local_ioc_getversion;
+        break;
+    }
+#endif
+
     if (ctx->export_flags & V9FS_SM_PASSTHROUGH) {
         ctx->xops = passthrough_xattr_ops;
     } else if (ctx->export_flags & V9FS_SM_MAPPED) {
@@ -1185,23 +1201,8 @@ static int local_init(FsContext *ctx)
         ctx->xops = passthrough_xattr_ops;
     }
     ctx->export_flags |= V9FS_PATHNAME_FSCONTEXT;
-#ifdef FS_IOC_GETVERSION
-    /*
-     * use ioc_getversion only if the iocl is definied
-     */
-    err = statfs(ctx->fs_root, &stbuf);
-    if (!err) {
-        switch (stbuf.f_type) {
-        case EXT2_SUPER_MAGIC:
-        case BTRFS_SUPER_MAGIC:
-        case REISERFS_SUPER_MAGIC:
-        case XFS_SUPER_MAGIC:
-            ctx->exops.get_st_gen = local_ioc_getversion;
-            break;
-        }
-    }
-#endif
-    return err;
+
+    return 0;
 }
 
 static int local_parse_opts(QemuOpts *opts, struct FsDriverEntry *fse)
-- 
cgit v1.1


From 21328e1e57f526e3f0c2fcd00f10c8aa6e7bc07f Mon Sep 17 00:00:00 2001
From: Greg Kurz <groug@kaod.org>
Date: Sun, 26 Feb 2017 23:41:55 +0100
Subject: 9pfs: remove side-effects in local_open() and local_opendir()

If these functions fail, they should not change *fs. Let's use local
variables to fix this.

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 hw/9pfs/9p-local.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

(limited to 'hw')

diff --git a/hw/9pfs/9p-local.c b/hw/9pfs/9p-local.c
index 4a8e628..607cd2a 100644
--- a/hw/9pfs/9p-local.c
+++ b/hw/9pfs/9p-local.c
@@ -356,10 +356,15 @@ static int local_open(FsContext *ctx, V9fsPath *fs_path,
 {
     char *buffer;
     char *path = fs_path->data;
+    int fd;
 
     buffer = rpath(ctx, path);
-    fs->fd = open(buffer, flags | O_NOFOLLOW);
+    fd = open(buffer, flags | O_NOFOLLOW);
     g_free(buffer);
+    if (fd == -1) {
+        return -1;
+    }
+    fs->fd = fd;
     return fs->fd;
 }
 
@@ -368,13 +373,15 @@ static int local_opendir(FsContext *ctx,
 {
     char *buffer;
     char *path = fs_path->data;
+    DIR *stream;
 
     buffer = rpath(ctx, path);
-    fs->dir.stream = opendir(buffer);
+    stream = opendir(buffer);
     g_free(buffer);
-    if (!fs->dir.stream) {
+    if (!stream) {
         return -1;
     }
+    fs->dir.stream = stream;
     return 0;
 }
 
-- 
cgit v1.1


From 6482a961636d66cc10928dde5d4d908206e5f65a Mon Sep 17 00:00:00 2001
From: Greg Kurz <groug@kaod.org>
Date: Sun, 26 Feb 2017 23:42:03 +0100
Subject: 9pfs: introduce relative_openat_nofollow() helper

When using the passthrough security mode, symbolic links created by the
guest are actual symbolic links on the host file system.

Since the resolution of symbolic links during path walk is supposed to
occur on the client side. The server should hence never receive any path
pointing to an actual symbolic link. This isn't guaranteed by the protocol
though, and malicious code in the guest can trick the server to issue
various syscalls on paths whose one or more elements are symbolic links.
In the case of the "local" backend using the "passthrough" or "none"
security modes, the guest can directly create symbolic links to arbitrary
locations on the host (as per spec). The "mapped-xattr" and "mapped-file"
security modes are also affected to a lesser extent as they require some
help from an external entity to create actual symbolic links on the host,
i.e. another guest using "passthrough" mode for example.

The current code hence relies on O_NOFOLLOW and "l*()" variants of system
calls. Unfortunately, this only applies to the rightmost path component.
A guest could maliciously replace any component in a trusted path with a
symbolic link. This could allow any guest to escape a virtfs shared folder.

This patch introduces a variant of the openat() syscall that successively
opens each path element with O_NOFOLLOW. When passing a file descriptor
pointing to a trusted directory, one is guaranteed to be returned a
file descriptor pointing to a path which is beneath the trusted directory.
This will be used by subsequent patches to implement symlink-safe path walk
for any access to the backend.

Symbolic links aren't the only threats actually: a malicious guest could
change a path element to point to other types of file with undesirable
effects:
- a named pipe or any other thing that would cause openat() to block
- a terminal device which would become QEMU's controlling terminal

These issues can be addressed with O_NONBLOCK and O_NOCTTY.

Two helpers are introduced: one to open intermediate path elements and one
to open the rightmost path element.

Suggested-by: Jann Horn <jannh@google.com>
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
(renamed openat_nofollow() to relative_openat_nofollow(),
 assert path is relative and doesn't contain '//',
 fixed side-effect in assert, Greg Kurz)
Signed-off-by: Greg Kurz <groug@kaod.org>
---
 hw/9pfs/9p-util.c     | 57 +++++++++++++++++++++++++++++++++++++++++++++++++++
 hw/9pfs/9p-util.h     | 50 ++++++++++++++++++++++++++++++++++++++++++++
 hw/9pfs/Makefile.objs |  2 +-
 3 files changed, 108 insertions(+), 1 deletion(-)
 create mode 100644 hw/9pfs/9p-util.c
 create mode 100644 hw/9pfs/9p-util.h

(limited to 'hw')

diff --git a/hw/9pfs/9p-util.c b/hw/9pfs/9p-util.c
new file mode 100644
index 0000000..54134b0
--- /dev/null
+++ b/hw/9pfs/9p-util.c
@@ -0,0 +1,57 @@
+/*
+ * 9p utilities
+ *
+ * Copyright IBM, Corp. 2017
+ *
+ * Authors:
+ *  Greg Kurz <groug@kaod.org>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+
+#include "qemu/osdep.h"
+#include "9p-util.h"
+
+int relative_openat_nofollow(int dirfd, const char *path, int flags,
+                             mode_t mode)
+{
+    int fd;
+
+    fd = dup(dirfd);
+    if (fd == -1) {
+        return -1;
+    }
+
+    while (*path) {
+        const char *c;
+        int next_fd;
+        char *head;
+
+        /* Only relative paths without consecutive slashes */
+        assert(path[0] != '/');
+
+        head = g_strdup(path);
+        c = strchr(path, '/');
+        if (c) {
+            head[c - path] = 0;
+            next_fd = openat_dir(fd, head);
+        } else {
+            next_fd = openat_file(fd, head, flags, mode);
+        }
+        g_free(head);
+        if (next_fd == -1) {
+            close_preserve_errno(fd);
+            return -1;
+        }
+        close(fd);
+        fd = next_fd;
+
+        if (!c) {
+            break;
+        }
+        path = c + 1;
+    }
+
+    return fd;
+}
diff --git a/hw/9pfs/9p-util.h b/hw/9pfs/9p-util.h
new file mode 100644
index 0000000..e80b5a5
--- /dev/null
+++ b/hw/9pfs/9p-util.h
@@ -0,0 +1,50 @@
+/*
+ * 9p utilities
+ *
+ * Copyright IBM, Corp. 2017
+ *
+ * Authors:
+ *  Greg Kurz <groug@kaod.org>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+
+#ifndef QEMU_9P_UTIL_H
+#define QEMU_9P_UTIL_H
+
+static inline void close_preserve_errno(int fd)
+{
+    int serrno = errno;
+    close(fd);
+    errno = serrno;
+}
+
+static inline int openat_dir(int dirfd, const char *name)
+{
+    return openat(dirfd, name, O_DIRECTORY | O_RDONLY | O_PATH);
+}
+
+static inline int openat_file(int dirfd, const char *name, int flags,
+                              mode_t mode)
+{
+    int fd, serrno, ret;
+
+    fd = openat(dirfd, name, flags | O_NOFOLLOW | O_NOCTTY | O_NONBLOCK,
+                mode);
+    if (fd == -1) {
+        return -1;
+    }
+
+    serrno = errno;
+    /* O_NONBLOCK was only needed to open the file. Let's drop it. */
+    ret = fcntl(fd, F_SETFL, flags);
+    assert(!ret);
+    errno = serrno;
+    return fd;
+}
+
+int relative_openat_nofollow(int dirfd, const char *path, int flags,
+                             mode_t mode);
+
+#endif
diff --git a/hw/9pfs/Makefile.objs b/hw/9pfs/Makefile.objs
index da0ae0c..32197e6 100644
--- a/hw/9pfs/Makefile.objs
+++ b/hw/9pfs/Makefile.objs
@@ -1,4 +1,4 @@
-common-obj-y  = 9p.o
+common-obj-y  = 9p.o 9p-util.o
 common-obj-y += 9p-local.o 9p-xattr.o
 common-obj-y += 9p-xattr-user.o 9p-posix-acl.o
 common-obj-y += coth.o cofs.o codir.o cofile.o
-- 
cgit v1.1


From 0e35a3782948c6154d7fafe9a02a86bc130199c7 Mon Sep 17 00:00:00 2001
From: Greg Kurz <groug@kaod.org>
Date: Sun, 26 Feb 2017 23:42:10 +0100
Subject: 9pfs: local: keep a file descriptor on the shared folder

This patch opens the shared folder and caches the file descriptor, so that
it can be used to do symlink-safe path walk.

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 hw/9pfs/9p-local.c | 30 ++++++++++++++++++++++++++++--
 1 file changed, 28 insertions(+), 2 deletions(-)

(limited to 'hw')

diff --git a/hw/9pfs/9p-local.c b/hw/9pfs/9p-local.c
index 607cd2a..be6be61 100644
--- a/hw/9pfs/9p-local.c
+++ b/hw/9pfs/9p-local.c
@@ -14,6 +14,7 @@
 #include "qemu/osdep.h"
 #include "9p.h"
 #include "9p-xattr.h"
+#include "9p-util.h"
 #include "fsdev/qemu-fsdev.h"   /* local_ops */
 #include <arpa/inet.h>
 #include <pwd.h>
@@ -43,6 +44,10 @@
 #define BTRFS_SUPER_MAGIC 0x9123683E
 #endif
 
+typedef struct {
+    int mountfd;
+} LocalData;
+
 #define VIRTFS_META_DIR ".virtfs_metadata"
 
 static char *local_mapped_attr_path(FsContext *ctx, const char *path)
@@ -1176,13 +1181,20 @@ static int local_ioc_getversion(FsContext *ctx, V9fsPath *path,
 static int local_init(FsContext *ctx)
 {
     struct statfs stbuf;
+    LocalData *data = g_malloc(sizeof(*data));
+
+    data->mountfd = open(ctx->fs_root, O_DIRECTORY | O_RDONLY);
+    if (data->mountfd == -1) {
+        goto err;
+    }
 
 #ifdef FS_IOC_GETVERSION
     /*
      * use ioc_getversion only if the ioctl is definied
      */
-    if (statfs(ctx->fs_root, &stbuf) < 0) {
-        return -1;
+    if (fstatfs(data->mountfd, &stbuf) < 0) {
+        close_preserve_errno(data->mountfd);
+        goto err;
     }
     switch (stbuf.f_type) {
     case EXT2_SUPER_MAGIC:
@@ -1209,7 +1221,20 @@ static int local_init(FsContext *ctx)
     }
     ctx->export_flags |= V9FS_PATHNAME_FSCONTEXT;
 
+    ctx->private = data;
     return 0;
+
+err:
+    g_free(data);
+    return -1;
+}
+
+static void local_cleanup(FsContext *ctx)
+{
+    LocalData *data = ctx->private;
+
+    close(data->mountfd);
+    g_free(data);
 }
 
 static int local_parse_opts(QemuOpts *opts, struct FsDriverEntry *fse)
@@ -1252,6 +1277,7 @@ static int local_parse_opts(QemuOpts *opts, struct FsDriverEntry *fse)
 FileOperations local_ops = {
     .parse_opts = local_parse_opts,
     .init  = local_init,
+    .cleanup = local_cleanup,
     .lstat = local_lstat,
     .readlink = local_readlink,
     .close = local_close,
-- 
cgit v1.1


From 996a0d76d7e756e4023ef79bc37bfe629b9eaca7 Mon Sep 17 00:00:00 2001
From: Greg Kurz <groug@kaod.org>
Date: Sun, 26 Feb 2017 23:42:18 +0100
Subject: 9pfs: local: open/opendir: don't follow symlinks

The local_open() and local_opendir() callbacks are vulnerable to symlink
attacks because they call:

(1) open(O_NOFOLLOW) which follows symbolic links in all path elements but
    the rightmost one
(2) opendir() which follows symbolic links in all path elements

This patch converts both callbacks to use new helpers based on
openat_nofollow() to only open files and directories if they are
below the virtfs shared folder

This partly fixes CVE-2016-9602.

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 hw/9pfs/9p-local.c | 37 +++++++++++++++++++++++++++----------
 hw/9pfs/9p-local.h | 20 ++++++++++++++++++++
 2 files changed, 47 insertions(+), 10 deletions(-)
 create mode 100644 hw/9pfs/9p-local.h

(limited to 'hw')

diff --git a/hw/9pfs/9p-local.c b/hw/9pfs/9p-local.c
index be6be61..2c491af 100644
--- a/hw/9pfs/9p-local.c
+++ b/hw/9pfs/9p-local.c
@@ -13,6 +13,7 @@
 
 #include "qemu/osdep.h"
 #include "9p.h"
+#include "9p-local.h"
 #include "9p-xattr.h"
 #include "9p-util.h"
 #include "fsdev/qemu-fsdev.h"   /* local_ops */
@@ -48,6 +49,24 @@ typedef struct {
     int mountfd;
 } LocalData;
 
+int local_open_nofollow(FsContext *fs_ctx, const char *path, int flags,
+                        mode_t mode)
+{
+    LocalData *data = fs_ctx->private;
+
+    /* All paths are relative to the path data->mountfd points to */
+    while (*path == '/') {
+        path++;
+    }
+
+    return relative_openat_nofollow(data->mountfd, path, flags, mode);
+}
+
+int local_opendir_nofollow(FsContext *fs_ctx, const char *path)
+{
+    return local_open_nofollow(fs_ctx, path, O_DIRECTORY | O_RDONLY, 0);
+}
+
 #define VIRTFS_META_DIR ".virtfs_metadata"
 
 static char *local_mapped_attr_path(FsContext *ctx, const char *path)
@@ -359,13 +378,9 @@ static int local_closedir(FsContext *ctx, V9fsFidOpenState *fs)
 static int local_open(FsContext *ctx, V9fsPath *fs_path,
                       int flags, V9fsFidOpenState *fs)
 {
-    char *buffer;
-    char *path = fs_path->data;
     int fd;
 
-    buffer = rpath(ctx, path);
-    fd = open(buffer, flags | O_NOFOLLOW);
-    g_free(buffer);
+    fd = local_open_nofollow(ctx, fs_path->data, flags, 0);
     if (fd == -1) {
         return -1;
     }
@@ -376,13 +391,15 @@ static int local_open(FsContext *ctx, V9fsPath *fs_path,
 static int local_opendir(FsContext *ctx,
                          V9fsPath *fs_path, V9fsFidOpenState *fs)
 {
-    char *buffer;
-    char *path = fs_path->data;
+    int dirfd;
     DIR *stream;
 
-    buffer = rpath(ctx, path);
-    stream = opendir(buffer);
-    g_free(buffer);
+    dirfd = local_opendir_nofollow(ctx, fs_path->data);
+    if (dirfd == -1) {
+        return -1;
+    }
+
+    stream = fdopendir(dirfd);
     if (!stream) {
         return -1;
     }
diff --git a/hw/9pfs/9p-local.h b/hw/9pfs/9p-local.h
new file mode 100644
index 0000000..32c7274
--- /dev/null
+++ b/hw/9pfs/9p-local.h
@@ -0,0 +1,20 @@
+/*
+ * 9p local backend utilities
+ *
+ * Copyright IBM, Corp. 2017
+ *
+ * Authors:
+ *  Greg Kurz <groug@kaod.org>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+
+#ifndef QEMU_9P_LOCAL_H
+#define QEMU_9P_LOCAL_H
+
+int local_open_nofollow(FsContext *fs_ctx, const char *path, int flags,
+                        mode_t mode);
+int local_opendir_nofollow(FsContext *fs_ctx, const char *path);
+
+#endif
-- 
cgit v1.1


From 56ad3e54dad6cdcee8668d170df161d89581846f Mon Sep 17 00:00:00 2001
From: Greg Kurz <groug@kaod.org>
Date: Sun, 26 Feb 2017 23:42:26 +0100
Subject: 9pfs: local: lgetxattr: don't follow symlinks

The local_lgetxattr() callback is vulnerable to symlink attacks because
it calls lgetxattr() which follows symbolic links in all path elements but
the rightmost one.

This patch introduces a helper to emulate the non-existing fgetxattrat()
function: it is implemented with /proc/self/fd which provides a trusted
path that can be safely passed to lgetxattr().

local_lgetxattr() is converted to use this helper and opendir_nofollow().

This partly fixes CVE-2016-9602.

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 hw/9pfs/9p-posix-acl.c  | 16 ++--------------
 hw/9pfs/9p-util.c       | 12 ++++++++++++
 hw/9pfs/9p-util.h       |  2 ++
 hw/9pfs/9p-xattr-user.c |  8 +-------
 hw/9pfs/9p-xattr.c      | 31 ++++++++++++++++++++++++-------
 hw/9pfs/9p-xattr.h      |  2 ++
 6 files changed, 43 insertions(+), 28 deletions(-)

(limited to 'hw')

diff --git a/hw/9pfs/9p-posix-acl.c b/hw/9pfs/9p-posix-acl.c
index ec00318..9435e27 100644
--- a/hw/9pfs/9p-posix-acl.c
+++ b/hw/9pfs/9p-posix-acl.c
@@ -25,13 +25,7 @@
 static ssize_t mp_pacl_getxattr(FsContext *ctx, const char *path,
                                 const char *name, void *value, size_t size)
 {
-    char *buffer;
-    ssize_t ret;
-
-    buffer = rpath(ctx, path);
-    ret = lgetxattr(buffer, MAP_ACL_ACCESS, value, size);
-    g_free(buffer);
-    return ret;
+    return local_getxattr_nofollow(ctx, path, MAP_ACL_ACCESS, value, size);
 }
 
 static ssize_t mp_pacl_listxattr(FsContext *ctx, const char *path,
@@ -89,13 +83,7 @@ static int mp_pacl_removexattr(FsContext *ctx,
 static ssize_t mp_dacl_getxattr(FsContext *ctx, const char *path,
                                 const char *name, void *value, size_t size)
 {
-    char *buffer;
-    ssize_t ret;
-
-    buffer = rpath(ctx, path);
-    ret = lgetxattr(buffer, MAP_ACL_DEFAULT, value, size);
-    g_free(buffer);
-    return ret;
+    return local_getxattr_nofollow(ctx, path, MAP_ACL_DEFAULT, value, size);
 }
 
 static ssize_t mp_dacl_listxattr(FsContext *ctx, const char *path,
diff --git a/hw/9pfs/9p-util.c b/hw/9pfs/9p-util.c
index 54134b0..fdb4d57 100644
--- a/hw/9pfs/9p-util.c
+++ b/hw/9pfs/9p-util.c
@@ -11,6 +11,7 @@
  */
 
 #include "qemu/osdep.h"
+#include "qemu/xattr.h"
 #include "9p-util.h"
 
 int relative_openat_nofollow(int dirfd, const char *path, int flags,
@@ -55,3 +56,14 @@ int relative_openat_nofollow(int dirfd, const char *path, int flags,
 
     return fd;
 }
+
+ssize_t fgetxattrat_nofollow(int dirfd, const char *filename, const char *name,
+                             void *value, size_t size)
+{
+    char *proc_path = g_strdup_printf("/proc/self/fd/%d/%s", dirfd, filename);
+    int ret;
+
+    ret = lgetxattr(proc_path, name, value, size);
+    g_free(proc_path);
+    return ret;
+}
diff --git a/hw/9pfs/9p-util.h b/hw/9pfs/9p-util.h
index e80b5a5..676641f 100644
--- a/hw/9pfs/9p-util.h
+++ b/hw/9pfs/9p-util.h
@@ -46,5 +46,7 @@ static inline int openat_file(int dirfd, const char *name, int flags,
 
 int relative_openat_nofollow(int dirfd, const char *path, int flags,
                              mode_t mode);
+ssize_t fgetxattrat_nofollow(int dirfd, const char *path, const char *name,
+                             void *value, size_t size);
 
 #endif
diff --git a/hw/9pfs/9p-xattr-user.c b/hw/9pfs/9p-xattr-user.c
index f87530c..4071fbc 100644
--- a/hw/9pfs/9p-xattr-user.c
+++ b/hw/9pfs/9p-xattr-user.c
@@ -20,9 +20,6 @@
 static ssize_t mp_user_getxattr(FsContext *ctx, const char *path,
                                 const char *name, void *value, size_t size)
 {
-    char *buffer;
-    ssize_t ret;
-
     if (strncmp(name, "user.virtfs.", 12) == 0) {
         /*
          * Don't allow fetch of user.virtfs namesapce
@@ -31,10 +28,7 @@ static ssize_t mp_user_getxattr(FsContext *ctx, const char *path,
         errno = ENOATTR;
         return -1;
     }
-    buffer = rpath(ctx, path);
-    ret = lgetxattr(buffer, name, value, size);
-    g_free(buffer);
-    return ret;
+    return local_getxattr_nofollow(ctx, path, name, value, size);
 }
 
 static ssize_t mp_user_listxattr(FsContext *ctx, const char *path,
diff --git a/hw/9pfs/9p-xattr.c b/hw/9pfs/9p-xattr.c
index 19a2daf..aa4391e 100644
--- a/hw/9pfs/9p-xattr.c
+++ b/hw/9pfs/9p-xattr.c
@@ -15,6 +15,8 @@
 #include "9p.h"
 #include "fsdev/file-op-9p.h"
 #include "9p-xattr.h"
+#include "9p-util.h"
+#include "9p-local.h"
 
 
 static XattrOperations *get_xattr_operations(XattrOperations **h,
@@ -143,18 +145,33 @@ int v9fs_remove_xattr(FsContext *ctx,
 
 }
 
-ssize_t pt_getxattr(FsContext *ctx, const char *path, const char *name,
-                    void *value, size_t size)
+ssize_t local_getxattr_nofollow(FsContext *ctx, const char *path,
+                                const char *name, void *value, size_t size)
 {
-    char *buffer;
-    ssize_t ret;
+    char *dirpath = g_path_get_dirname(path);
+    char *filename = g_path_get_basename(path);
+    int dirfd;
+    ssize_t ret = -1;
+
+    dirfd = local_opendir_nofollow(ctx, dirpath);
+    if (dirfd == -1) {
+        goto out;
+    }
 
-    buffer = rpath(ctx, path);
-    ret = lgetxattr(buffer, name, value, size);
-    g_free(buffer);
+    ret = fgetxattrat_nofollow(dirfd, filename, name, value, size);
+    close_preserve_errno(dirfd);
+out:
+    g_free(dirpath);
+    g_free(filename);
     return ret;
 }
 
+ssize_t pt_getxattr(FsContext *ctx, const char *path, const char *name,
+                    void *value, size_t size)
+{
+    return local_getxattr_nofollow(ctx, path, name, value, size);
+}
+
 int pt_setxattr(FsContext *ctx, const char *path, const char *name, void *value,
                 size_t size, int flags)
 {
diff --git a/hw/9pfs/9p-xattr.h b/hw/9pfs/9p-xattr.h
index 3f43f51..69a8b6b 100644
--- a/hw/9pfs/9p-xattr.h
+++ b/hw/9pfs/9p-xattr.h
@@ -29,6 +29,8 @@ typedef struct xattr_operations
                        const char *path, const char *name);
 } XattrOperations;
 
+ssize_t local_getxattr_nofollow(FsContext *ctx, const char *path,
+                                const char *name, void *value, size_t size);
 
 extern XattrOperations mapped_user_xattr;
 extern XattrOperations passthrough_user_xattr;
-- 
cgit v1.1


From 5507904e362df252f6065cb27d1ff98372db6abc Mon Sep 17 00:00:00 2001
From: Greg Kurz <groug@kaod.org>
Date: Sun, 26 Feb 2017 23:42:34 +0100
Subject: 9pfs: local: llistxattr: don't follow symlinks

The local_llistxattr() callback is vulnerable to symlink attacks because
it calls llistxattr() which follows symbolic links in all path elements but
the rightmost one.

This patch introduces a helper to emulate the non-existing flistxattrat()
function: it is implemented with /proc/self/fd which provides a trusted
path that can be safely passed to llistxattr().

local_llistxattr() is converted to use this helper and opendir_nofollow().

This partly fixes CVE-2016-9602.

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 hw/9pfs/9p-xattr.c | 35 +++++++++++++++++++++++++++++------
 1 file changed, 29 insertions(+), 6 deletions(-)

(limited to 'hw')

diff --git a/hw/9pfs/9p-xattr.c b/hw/9pfs/9p-xattr.c
index aa4391e..54193c6 100644
--- a/hw/9pfs/9p-xattr.c
+++ b/hw/9pfs/9p-xattr.c
@@ -60,6 +60,16 @@ ssize_t pt_listxattr(FsContext *ctx, const char *path,
     return name_size;
 }
 
+static ssize_t flistxattrat_nofollow(int dirfd, const char *filename,
+                                     char *list, size_t size)
+{
+    char *proc_path = g_strdup_printf("/proc/self/fd/%d/%s", dirfd, filename);
+    int ret;
+
+    ret = llistxattr(proc_path, list, size);
+    g_free(proc_path);
+    return ret;
+}
 
 /*
  * Get the list and pass to each layer to find out whether
@@ -69,24 +79,37 @@ ssize_t v9fs_list_xattr(FsContext *ctx, const char *path,
                         void *value, size_t vsize)
 {
     ssize_t size = 0;
-    char *buffer;
     void *ovalue = value;
     XattrOperations *xops;
     char *orig_value, *orig_value_start;
     ssize_t xattr_len, parsed_len = 0, attr_len;
+    char *dirpath, *name;
+    int dirfd;
 
     /* Get the actual len */
-    buffer = rpath(ctx, path);
-    xattr_len = llistxattr(buffer, value, 0);
+    dirpath = g_path_get_dirname(path);
+    dirfd = local_opendir_nofollow(ctx, dirpath);
+    g_free(dirpath);
+    if (dirfd == -1) {
+        return -1;
+    }
+
+    name = g_path_get_basename(path);
+    xattr_len = flistxattrat_nofollow(dirfd, name, value, 0);
     if (xattr_len <= 0) {
-        g_free(buffer);
+        g_free(name);
+        close_preserve_errno(dirfd);
         return xattr_len;
     }
 
     /* Now fetch the xattr and find the actual size */
     orig_value = g_malloc(xattr_len);
-    xattr_len = llistxattr(buffer, orig_value, xattr_len);
-    g_free(buffer);
+    xattr_len = flistxattrat_nofollow(dirfd, name, orig_value, xattr_len);
+    g_free(name);
+    close_preserve_errno(dirfd);
+    if (xattr_len < 0) {
+        return -1;
+    }
 
     /* store the orig pointer */
     orig_value_start = orig_value;
-- 
cgit v1.1


From 3e36aba757f76673007a80b3cd56a4062c2e3462 Mon Sep 17 00:00:00 2001
From: Greg Kurz <groug@kaod.org>
Date: Sun, 26 Feb 2017 23:42:43 +0100
Subject: 9pfs: local: lsetxattr: don't follow symlinks

The local_lsetxattr() callback is vulnerable to symlink attacks because
it calls lsetxattr() which follows symbolic links in all path elements but
the rightmost one.

This patch introduces a helper to emulate the non-existing fsetxattrat()
function: it is implemented with /proc/self/fd which provides a trusted
path that can be safely passed to lsetxattr().

local_lsetxattr() is converted to use this helper and opendir_nofollow().

This partly fixes CVE-2016-9602.

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 hw/9pfs/9p-posix-acl.c  | 18 ++++--------------
 hw/9pfs/9p-util.h       |  2 ++
 hw/9pfs/9p-xattr-user.c |  8 +-------
 hw/9pfs/9p-xattr.c      | 39 +++++++++++++++++++++++++++++++++------
 hw/9pfs/9p-xattr.h      |  3 +++
 5 files changed, 43 insertions(+), 27 deletions(-)

(limited to 'hw')

diff --git a/hw/9pfs/9p-posix-acl.c b/hw/9pfs/9p-posix-acl.c
index 9435e27..0154e2a 100644
--- a/hw/9pfs/9p-posix-acl.c
+++ b/hw/9pfs/9p-posix-acl.c
@@ -50,13 +50,8 @@ static ssize_t mp_pacl_listxattr(FsContext *ctx, const char *path,
 static int mp_pacl_setxattr(FsContext *ctx, const char *path, const char *name,
                             void *value, size_t size, int flags)
 {
-    char *buffer;
-    int ret;
-
-    buffer = rpath(ctx, path);
-    ret = lsetxattr(buffer, MAP_ACL_ACCESS, value, size, flags);
-    g_free(buffer);
-    return ret;
+    return local_setxattr_nofollow(ctx, path, MAP_ACL_ACCESS, value, size,
+                                   flags);
 }
 
 static int mp_pacl_removexattr(FsContext *ctx,
@@ -108,13 +103,8 @@ static ssize_t mp_dacl_listxattr(FsContext *ctx, const char *path,
 static int mp_dacl_setxattr(FsContext *ctx, const char *path, const char *name,
                             void *value, size_t size, int flags)
 {
-    char *buffer;
-    int ret;
-
-    buffer = rpath(ctx, path);
-    ret = lsetxattr(buffer, MAP_ACL_DEFAULT, value, size, flags);
-    g_free(buffer);
-    return ret;
+    return local_setxattr_nofollow(ctx, path, MAP_ACL_DEFAULT, value, size,
+                                   flags);
 }
 
 static int mp_dacl_removexattr(FsContext *ctx,
diff --git a/hw/9pfs/9p-util.h b/hw/9pfs/9p-util.h
index 676641f..091f3ce 100644
--- a/hw/9pfs/9p-util.h
+++ b/hw/9pfs/9p-util.h
@@ -48,5 +48,7 @@ int relative_openat_nofollow(int dirfd, const char *path, int flags,
                              mode_t mode);
 ssize_t fgetxattrat_nofollow(int dirfd, const char *path, const char *name,
                              void *value, size_t size);
+int fsetxattrat_nofollow(int dirfd, const char *path, const char *name,
+                         void *value, size_t size, int flags);
 
 #endif
diff --git a/hw/9pfs/9p-xattr-user.c b/hw/9pfs/9p-xattr-user.c
index 4071fbc..1840a5d 100644
--- a/hw/9pfs/9p-xattr-user.c
+++ b/hw/9pfs/9p-xattr-user.c
@@ -67,9 +67,6 @@ static ssize_t mp_user_listxattr(FsContext *ctx, const char *path,
 static int mp_user_setxattr(FsContext *ctx, const char *path, const char *name,
                             void *value, size_t size, int flags)
 {
-    char *buffer;
-    int ret;
-
     if (strncmp(name, "user.virtfs.", 12) == 0) {
         /*
          * Don't allow fetch of user.virtfs namesapce
@@ -78,10 +75,7 @@ static int mp_user_setxattr(FsContext *ctx, const char *path, const char *name,
         errno = EACCES;
         return -1;
     }
-    buffer = rpath(ctx, path);
-    ret = lsetxattr(buffer, name, value, size, flags);
-    g_free(buffer);
-    return ret;
+    return local_setxattr_nofollow(ctx, path, name, value, size, flags);
 }
 
 static int mp_user_removexattr(FsContext *ctx,
diff --git a/hw/9pfs/9p-xattr.c b/hw/9pfs/9p-xattr.c
index 54193c6..a0167dd 100644
--- a/hw/9pfs/9p-xattr.c
+++ b/hw/9pfs/9p-xattr.c
@@ -195,18 +195,45 @@ ssize_t pt_getxattr(FsContext *ctx, const char *path, const char *name,
     return local_getxattr_nofollow(ctx, path, name, value, size);
 }
 
-int pt_setxattr(FsContext *ctx, const char *path, const char *name, void *value,
-                size_t size, int flags)
+int fsetxattrat_nofollow(int dirfd, const char *filename, const char *name,
+                         void *value, size_t size, int flags)
 {
-    char *buffer;
+    char *proc_path = g_strdup_printf("/proc/self/fd/%d/%s", dirfd, filename);
     int ret;
 
-    buffer = rpath(ctx, path);
-    ret = lsetxattr(buffer, name, value, size, flags);
-    g_free(buffer);
+    ret = lsetxattr(proc_path, name, value, size, flags);
+    g_free(proc_path);
+    return ret;
+}
+
+ssize_t local_setxattr_nofollow(FsContext *ctx, const char *path,
+                                const char *name, void *value, size_t size,
+                                int flags)
+{
+    char *dirpath = g_path_get_dirname(path);
+    char *filename = g_path_get_basename(path);
+    int dirfd;
+    ssize_t ret = -1;
+
+    dirfd = local_opendir_nofollow(ctx, dirpath);
+    if (dirfd == -1) {
+        goto out;
+    }
+
+    ret = fsetxattrat_nofollow(dirfd, filename, name, value, size, flags);
+    close_preserve_errno(dirfd);
+out:
+    g_free(dirpath);
+    g_free(filename);
     return ret;
 }
 
+int pt_setxattr(FsContext *ctx, const char *path, const char *name, void *value,
+                size_t size, int flags)
+{
+    return local_setxattr_nofollow(ctx, path, name, value, size, flags);
+}
+
 int pt_removexattr(FsContext *ctx, const char *path, const char *name)
 {
     char *buffer;
diff --git a/hw/9pfs/9p-xattr.h b/hw/9pfs/9p-xattr.h
index 69a8b6b..7558970 100644
--- a/hw/9pfs/9p-xattr.h
+++ b/hw/9pfs/9p-xattr.h
@@ -31,6 +31,9 @@ typedef struct xattr_operations
 
 ssize_t local_getxattr_nofollow(FsContext *ctx, const char *path,
                                 const char *name, void *value, size_t size);
+ssize_t local_setxattr_nofollow(FsContext *ctx, const char *path,
+                                const char *name, void *value, size_t size,
+                                int flags);
 
 extern XattrOperations mapped_user_xattr;
 extern XattrOperations passthrough_user_xattr;
-- 
cgit v1.1


From 72f0d0bf51362011c4d841a89fb8f5cfb16e0bf3 Mon Sep 17 00:00:00 2001
From: Greg Kurz <groug@kaod.org>
Date: Sun, 26 Feb 2017 23:42:51 +0100
Subject: 9pfs: local: lremovexattr: don't follow symlinks

The local_lremovexattr() callback is vulnerable to symlink attacks because
it calls lremovexattr() which follows symbolic links in all path elements
but the rightmost one.

This patch introduces a helper to emulate the non-existing fremovexattrat()
function: it is implemented with /proc/self/fd which provides a trusted
path that can be safely passed to lremovexattr().

local_lremovexattr() is converted to use this helper and opendir_nofollow().

This partly fixes CVE-2016-9602.

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 hw/9pfs/9p-posix-acl.c  | 10 ++--------
 hw/9pfs/9p-xattr-user.c |  8 +-------
 hw/9pfs/9p-xattr.c      | 36 +++++++++++++++++++++++++++++++-----
 hw/9pfs/9p-xattr.h      |  2 ++
 4 files changed, 36 insertions(+), 20 deletions(-)

(limited to 'hw')

diff --git a/hw/9pfs/9p-posix-acl.c b/hw/9pfs/9p-posix-acl.c
index 0154e2a..bbf8906 100644
--- a/hw/9pfs/9p-posix-acl.c
+++ b/hw/9pfs/9p-posix-acl.c
@@ -58,10 +58,8 @@ static int mp_pacl_removexattr(FsContext *ctx,
                                const char *path, const char *name)
 {
     int ret;
-    char *buffer;
 
-    buffer = rpath(ctx, path);
-    ret  = lremovexattr(buffer, MAP_ACL_ACCESS);
+    ret = local_removexattr_nofollow(ctx, path, MAP_ACL_ACCESS);
     if (ret == -1 && errno == ENODATA) {
         /*
          * We don't get ENODATA error when trying to remove a
@@ -71,7 +69,6 @@ static int mp_pacl_removexattr(FsContext *ctx,
         errno = 0;
         ret = 0;
     }
-    g_free(buffer);
     return ret;
 }
 
@@ -111,10 +108,8 @@ static int mp_dacl_removexattr(FsContext *ctx,
                                const char *path, const char *name)
 {
     int ret;
-    char *buffer;
 
-    buffer = rpath(ctx, path);
-    ret  = lremovexattr(buffer, MAP_ACL_DEFAULT);
+    ret = local_removexattr_nofollow(ctx, path, MAP_ACL_DEFAULT);
     if (ret == -1 && errno == ENODATA) {
         /*
          * We don't get ENODATA error when trying to remove a
@@ -124,7 +119,6 @@ static int mp_dacl_removexattr(FsContext *ctx,
         errno = 0;
         ret = 0;
     }
-    g_free(buffer);
     return ret;
 }
 
diff --git a/hw/9pfs/9p-xattr-user.c b/hw/9pfs/9p-xattr-user.c
index 1840a5d..2c90817 100644
--- a/hw/9pfs/9p-xattr-user.c
+++ b/hw/9pfs/9p-xattr-user.c
@@ -81,9 +81,6 @@ static int mp_user_setxattr(FsContext *ctx, const char *path, const char *name,
 static int mp_user_removexattr(FsContext *ctx,
                                const char *path, const char *name)
 {
-    char *buffer;
-    int ret;
-
     if (strncmp(name, "user.virtfs.", 12) == 0) {
         /*
          * Don't allow fetch of user.virtfs namesapce
@@ -92,10 +89,7 @@ static int mp_user_removexattr(FsContext *ctx,
         errno = EACCES;
         return -1;
     }
-    buffer = rpath(ctx, path);
-    ret = lremovexattr(buffer, name);
-    g_free(buffer);
-    return ret;
+    return local_removexattr_nofollow(ctx, path, name);
 }
 
 XattrOperations mapped_user_xattr = {
diff --git a/hw/9pfs/9p-xattr.c b/hw/9pfs/9p-xattr.c
index a0167dd..eec160b 100644
--- a/hw/9pfs/9p-xattr.c
+++ b/hw/9pfs/9p-xattr.c
@@ -234,17 +234,43 @@ int pt_setxattr(FsContext *ctx, const char *path, const char *name, void *value,
     return local_setxattr_nofollow(ctx, path, name, value, size, flags);
 }
 
-int pt_removexattr(FsContext *ctx, const char *path, const char *name)
+static ssize_t fremovexattrat_nofollow(int dirfd, const char *filename,
+                                       const char *name)
 {
-    char *buffer;
+    char *proc_path = g_strdup_printf("/proc/self/fd/%d/%s", dirfd, filename);
     int ret;
 
-    buffer = rpath(ctx, path);
-    ret = lremovexattr(path, name);
-    g_free(buffer);
+    ret = lremovexattr(proc_path, name);
+    g_free(proc_path);
     return ret;
 }
 
+ssize_t local_removexattr_nofollow(FsContext *ctx, const char *path,
+                                   const char *name)
+{
+    char *dirpath = g_path_get_dirname(path);
+    char *filename = g_path_get_basename(path);
+    int dirfd;
+    ssize_t ret = -1;
+
+    dirfd = local_opendir_nofollow(ctx, dirpath);
+    if (dirfd == -1) {
+        goto out;
+    }
+
+    ret = fremovexattrat_nofollow(dirfd, filename, name);
+    close_preserve_errno(dirfd);
+out:
+    g_free(dirpath);
+    g_free(filename);
+    return ret;
+}
+
+int pt_removexattr(FsContext *ctx, const char *path, const char *name)
+{
+    return local_removexattr_nofollow(ctx, path, name);
+}
+
 ssize_t notsup_getxattr(FsContext *ctx, const char *path, const char *name,
                         void *value, size_t size)
 {
diff --git a/hw/9pfs/9p-xattr.h b/hw/9pfs/9p-xattr.h
index 7558970..0d83996 100644
--- a/hw/9pfs/9p-xattr.h
+++ b/hw/9pfs/9p-xattr.h
@@ -34,6 +34,8 @@ ssize_t local_getxattr_nofollow(FsContext *ctx, const char *path,
 ssize_t local_setxattr_nofollow(FsContext *ctx, const char *path,
                                 const char *name, void *value, size_t size,
                                 int flags);
+ssize_t local_removexattr_nofollow(FsContext *ctx, const char *path,
+                                   const char *name);
 
 extern XattrOperations mapped_user_xattr;
 extern XattrOperations passthrough_user_xattr;
-- 
cgit v1.1


From df4938a6651b1f980018f9eaf86af43e6b9d7fed Mon Sep 17 00:00:00 2001
From: Greg Kurz <groug@kaod.org>
Date: Sun, 26 Feb 2017 23:43:00 +0100
Subject: 9pfs: local: unlinkat: don't follow symlinks

The local_unlinkat() callback is vulnerable to symlink attacks because it
calls remove() which follows symbolic links in all path elements but the
rightmost one.

This patch converts local_unlinkat() to rely on opendir_nofollow() and
unlinkat() instead.

Most of the code is moved to a separate local_unlinkat_common() helper
which will be reused in a subsequent patch to fix the same issue in
local_remove().

This partly fixes CVE-2016-9602.

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 hw/9pfs/9p-local.c | 99 ++++++++++++++++++++++++++++++------------------------
 1 file changed, 56 insertions(+), 43 deletions(-)

(limited to 'hw')

diff --git a/hw/9pfs/9p-local.c b/hw/9pfs/9p-local.c
index 2c491af..04de511 100644
--- a/hw/9pfs/9p-local.c
+++ b/hw/9pfs/9p-local.c
@@ -969,6 +969,56 @@ static int local_utimensat(FsContext *s, V9fsPath *fs_path,
     return ret;
 }
 
+static int local_unlinkat_common(FsContext *ctx, int dirfd, const char *name,
+                                 int flags)
+{
+    int ret = -1;
+
+    if (ctx->export_flags & V9FS_SM_MAPPED_FILE) {
+        int map_dirfd;
+
+        if (flags == AT_REMOVEDIR) {
+            int fd;
+
+            fd = openat(dirfd, name, O_RDONLY | O_DIRECTORY | O_PATH);
+            if (fd == -1) {
+                goto err_out;
+            }
+            /*
+             * If directory remove .virtfs_metadata contained in the
+             * directory
+             */
+            ret = unlinkat(fd, VIRTFS_META_DIR, AT_REMOVEDIR);
+            close_preserve_errno(fd);
+            if (ret < 0 && errno != ENOENT) {
+                /*
+                 * We didn't had the .virtfs_metadata file. May be file created
+                 * in non-mapped mode ?. Ignore ENOENT.
+                 */
+                goto err_out;
+            }
+        }
+        /*
+         * Now remove the name from parent directory
+         * .virtfs_metadata directory.
+         */
+        map_dirfd = openat_dir(dirfd, VIRTFS_META_DIR);
+        ret = unlinkat(map_dirfd, name, 0);
+        close_preserve_errno(map_dirfd);
+        if (ret < 0 && errno != ENOENT) {
+            /*
+             * We didn't had the .virtfs_metadata file. May be file created
+             * in non-mapped mode ?. Ignore ENOENT.
+             */
+            goto err_out;
+        }
+    }
+
+    ret = unlinkat(dirfd, name, flags);
+err_out:
+    return ret;
+}
+
 static int local_remove(FsContext *ctx, const char *path)
 {
     int err;
@@ -1118,52 +1168,15 @@ static int local_unlinkat(FsContext *ctx, V9fsPath *dir,
                           const char *name, int flags)
 {
     int ret;
-    V9fsString fullname;
-    char *buffer;
-
-    v9fs_string_init(&fullname);
+    int dirfd;
 
-    v9fs_string_sprintf(&fullname, "%s/%s", dir->data, name);
-    if (ctx->export_flags & V9FS_SM_MAPPED_FILE) {
-        if (flags == AT_REMOVEDIR) {
-            /*
-             * If directory remove .virtfs_metadata contained in the
-             * directory
-             */
-            buffer = g_strdup_printf("%s/%s/%s", ctx->fs_root,
-                                     fullname.data, VIRTFS_META_DIR);
-            ret = remove(buffer);
-            g_free(buffer);
-            if (ret < 0 && errno != ENOENT) {
-                /*
-                 * We didn't had the .virtfs_metadata file. May be file created
-                 * in non-mapped mode ?. Ignore ENOENT.
-                 */
-                goto err_out;
-            }
-        }
-        /*
-         * Now remove the name from parent directory
-         * .virtfs_metadata directory.
-         */
-        buffer = local_mapped_attr_path(ctx, fullname.data);
-        ret = remove(buffer);
-        g_free(buffer);
-        if (ret < 0 && errno != ENOENT) {
-            /*
-             * We didn't had the .virtfs_metadata file. May be file created
-             * in non-mapped mode ?. Ignore ENOENT.
-             */
-            goto err_out;
-        }
+    dirfd = local_opendir_nofollow(ctx, dir->data);
+    if (dirfd == -1) {
+        return -1;
     }
-    /* Remove the name finally */
-    buffer = rpath(ctx, fullname.data);
-    ret = remove(buffer);
-    g_free(buffer);
 
-err_out:
-    v9fs_string_free(&fullname);
+    ret = local_unlinkat_common(ctx, dirfd, name, flags);
+    close_preserve_errno(dirfd);
     return ret;
 }
 
-- 
cgit v1.1


From a0e640a87210b1e986bcd4e7f7de03beb3db0a4a Mon Sep 17 00:00:00 2001
From: Greg Kurz <groug@kaod.org>
Date: Sun, 26 Feb 2017 23:43:08 +0100
Subject: 9pfs: local: remove: don't follow symlinks

The local_remove() callback is vulnerable to symlink attacks because it
calls:

(1) lstat() which follows symbolic links in all path elements but the
    rightmost one
(2) remove() which follows symbolic links in all path elements but the
    rightmost one

This patch converts local_remove() to rely on opendir_nofollow(),
fstatat(AT_SYMLINK_NOFOLLOW) to fix (1) and unlinkat() to fix (2).

This partly fixes CVE-2016-9602.

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 hw/9pfs/9p-local.c | 64 ++++++++++++++++++------------------------------------
 1 file changed, 21 insertions(+), 43 deletions(-)

(limited to 'hw')

diff --git a/hw/9pfs/9p-local.c b/hw/9pfs/9p-local.c
index 04de511..8fb79e4 100644
--- a/hw/9pfs/9p-local.c
+++ b/hw/9pfs/9p-local.c
@@ -1021,54 +1021,32 @@ err_out:
 
 static int local_remove(FsContext *ctx, const char *path)
 {
-    int err;
     struct stat stbuf;
-    char *buffer;
+    char *dirpath = g_path_get_dirname(path);
+    char *name = g_path_get_basename(path);
+    int flags = 0;
+    int dirfd;
+    int err = -1;
 
-    if (ctx->export_flags & V9FS_SM_MAPPED_FILE) {
-        buffer = rpath(ctx, path);
-        err =  lstat(buffer, &stbuf);
-        g_free(buffer);
-        if (err) {
-            goto err_out;
-        }
-        /*
-         * If directory remove .virtfs_metadata contained in the
-         * directory
-         */
-        if (S_ISDIR(stbuf.st_mode)) {
-            buffer = g_strdup_printf("%s/%s/%s", ctx->fs_root,
-                                     path, VIRTFS_META_DIR);
-            err = remove(buffer);
-            g_free(buffer);
-            if (err < 0 && errno != ENOENT) {
-                /*
-                 * We didn't had the .virtfs_metadata file. May be file created
-                 * in non-mapped mode ?. Ignore ENOENT.
-                 */
-                goto err_out;
-            }
-        }
-        /*
-         * Now remove the name from parent directory
-         * .virtfs_metadata directory
-         */
-        buffer = local_mapped_attr_path(ctx, path);
-        err = remove(buffer);
-        g_free(buffer);
-        if (err < 0 && errno != ENOENT) {
-            /*
-             * We didn't had the .virtfs_metadata file. May be file created
-             * in non-mapped mode ?. Ignore ENOENT.
-             */
-            goto err_out;
-        }
+    dirfd = local_opendir_nofollow(ctx, dirpath);
+    if (dirfd) {
+        goto out;
     }
 
-    buffer = rpath(ctx, path);
-    err = remove(buffer);
-    g_free(buffer);
+    if (fstatat(dirfd, path, &stbuf, AT_SYMLINK_NOFOLLOW) < 0) {
+        goto err_out;
+    }
+
+    if (S_ISDIR(stbuf.st_mode)) {
+        flags |= AT_REMOVEDIR;
+    }
+
+    err = local_unlinkat_common(ctx, dirfd, name, flags);
 err_out:
+    close_preserve_errno(dirfd);
+out:
+    g_free(name);
+    g_free(dirpath);
     return err;
 }
 
-- 
cgit v1.1


From a33eda0dd99e00faa3bacae43d19490bb9500e07 Mon Sep 17 00:00:00 2001
From: Greg Kurz <groug@kaod.org>
Date: Sun, 26 Feb 2017 23:43:17 +0100
Subject: 9pfs: local: utimensat: don't follow symlinks

The local_utimensat() callback is vulnerable to symlink attacks because it
calls qemu_utimens()->utimensat(AT_SYMLINK_NOFOLLOW) which follows symbolic
links in all path elements but the rightmost one or qemu_utimens()->utimes()
which follows symbolic links for all path elements.

This patch converts local_utimensat() to rely on opendir_nofollow() and
utimensat(AT_SYMLINK_NOFOLLOW) directly instead of using qemu_utimens().
It is hence assumed that the OS supports utimensat(), i.e. has glibc 2.6
or higher and linux 2.6.22 or higher, which seems reasonable nowadays.

This partly fixes CVE-2016-9602.

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 hw/9pfs/9p-local.c | 19 +++++++++++++------
 1 file changed, 13 insertions(+), 6 deletions(-)

(limited to 'hw')

diff --git a/hw/9pfs/9p-local.c b/hw/9pfs/9p-local.c
index 8fb79e4..a6dd77d 100644
--- a/hw/9pfs/9p-local.c
+++ b/hw/9pfs/9p-local.c
@@ -959,13 +959,20 @@ static int local_chown(FsContext *fs_ctx, V9fsPath *fs_path, FsCred *credp)
 static int local_utimensat(FsContext *s, V9fsPath *fs_path,
                            const struct timespec *buf)
 {
-    char *buffer;
-    int ret;
-    char *path = fs_path->data;
+    char *dirpath = g_path_get_dirname(fs_path->data);
+    char *name = g_path_get_basename(fs_path->data);
+    int dirfd, ret = -1;
 
-    buffer = rpath(s, path);
-    ret = qemu_utimens(buffer, buf);
-    g_free(buffer);
+    dirfd = local_opendir_nofollow(s, dirpath);
+    if (dirfd == -1) {
+        goto out;
+    }
+
+    ret = utimensat(dirfd, name, buf, AT_SYMLINK_NOFOLLOW);
+    close_preserve_errno(dirfd);
+out:
+    g_free(dirpath);
+    g_free(name);
     return ret;
 }
 
-- 
cgit v1.1


From 31e51d1c15b35dc98b88a301812914b70a2b55dc Mon Sep 17 00:00:00 2001
From: Greg Kurz <groug@kaod.org>
Date: Sun, 26 Feb 2017 23:43:25 +0100
Subject: 9pfs: local: statfs: don't follow symlinks

The local_statfs() callback is vulnerable to symlink attacks because it
calls statfs() which follows symbolic links in all path elements.

This patch converts local_statfs() to rely on open_nofollow() and fstatfs()
instead.

This partly fixes CVE-2016-9602.

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 hw/9pfs/9p-local.c | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

(limited to 'hw')

diff --git a/hw/9pfs/9p-local.c b/hw/9pfs/9p-local.c
index a6dd77d..95b2c1c 100644
--- a/hw/9pfs/9p-local.c
+++ b/hw/9pfs/9p-local.c
@@ -1077,13 +1077,11 @@ static int local_fsync(FsContext *ctx, int fid_type,
 
 static int local_statfs(FsContext *s, V9fsPath *fs_path, struct statfs *stbuf)
 {
-    char *buffer;
-    int ret;
-    char *path = fs_path->data;
+    int fd, ret;
 
-    buffer = rpath(s, path);
-    ret = statfs(buffer, stbuf);
-    g_free(buffer);
+    fd = local_open_nofollow(s, fs_path->data, O_RDONLY, 0);
+    ret = fstatfs(fd, stbuf);
+    close_preserve_errno(fd);
     return ret;
 }
 
-- 
cgit v1.1


From ac125d993b461d4dee4d6df4d93ac3f2eb959d1d Mon Sep 17 00:00:00 2001
From: Greg Kurz <groug@kaod.org>
Date: Sun, 26 Feb 2017 23:43:32 +0100
Subject: 9pfs: local: truncate: don't follow symlinks

The local_truncate() callback is vulnerable to symlink attacks because
it calls truncate() which follows symbolic links in all path elements.

This patch converts local_truncate() to rely on open_nofollow() and
ftruncate() instead.

This partly fixes CVE-2016-9602.

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 hw/9pfs/9p-local.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

(limited to 'hw')

diff --git a/hw/9pfs/9p-local.c b/hw/9pfs/9p-local.c
index 95b2c1c..1a3dfd7 100644
--- a/hw/9pfs/9p-local.c
+++ b/hw/9pfs/9p-local.c
@@ -894,13 +894,14 @@ err_out:
 
 static int local_truncate(FsContext *ctx, V9fsPath *fs_path, off_t size)
 {
-    char *buffer;
-    int ret;
-    char *path = fs_path->data;
+    int fd, ret;
 
-    buffer = rpath(ctx, path);
-    ret = truncate(buffer, size);
-    g_free(buffer);
+    fd = local_open_nofollow(ctx, fs_path->data, O_WRONLY, 0);
+    if (fd == -1) {
+        return -1;
+    }
+    ret = ftruncate(fd, size);
+    close_preserve_errno(fd);
     return ret;
 }
 
-- 
cgit v1.1


From bec1e9546e03b9e7f5152cf3e8c95cf8acff5e12 Mon Sep 17 00:00:00 2001
From: Greg Kurz <groug@kaod.org>
Date: Sun, 26 Feb 2017 23:43:40 +0100
Subject: 9pfs: local: readlink: don't follow symlinks

The local_readlink() callback is vulnerable to symlink attacks because it
calls:

(1) open(O_NOFOLLOW) which follows symbolic links for all path elements but
    the rightmost one
(2) readlink() which follows symbolic links for all path elements but the
    rightmost one

This patch converts local_readlink() to rely on open_nofollow() to fix (1)
and opendir_nofollow(), readlinkat() to fix (2).

This partly fixes CVE-2016-9602.

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 hw/9pfs/9p-local.c | 26 +++++++++++++++++---------
 1 file changed, 17 insertions(+), 9 deletions(-)

(limited to 'hw')

diff --git a/hw/9pfs/9p-local.c b/hw/9pfs/9p-local.c
index 1a3dfd7..e373cca 100644
--- a/hw/9pfs/9p-local.c
+++ b/hw/9pfs/9p-local.c
@@ -340,27 +340,35 @@ static ssize_t local_readlink(FsContext *fs_ctx, V9fsPath *fs_path,
                               char *buf, size_t bufsz)
 {
     ssize_t tsize = -1;
-    char *buffer;
-    char *path = fs_path->data;
 
     if ((fs_ctx->export_flags & V9FS_SM_MAPPED) ||
         (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE)) {
         int fd;
-        buffer = rpath(fs_ctx, path);
-        fd = open(buffer, O_RDONLY | O_NOFOLLOW);
-        g_free(buffer);
+
+        fd = local_open_nofollow(fs_ctx, fs_path->data, O_RDONLY, 0);
         if (fd == -1) {
             return -1;
         }
         do {
             tsize = read(fd, (void *)buf, bufsz);
         } while (tsize == -1 && errno == EINTR);
-        close(fd);
+        close_preserve_errno(fd);
     } else if ((fs_ctx->export_flags & V9FS_SM_PASSTHROUGH) ||
                (fs_ctx->export_flags & V9FS_SM_NONE)) {
-        buffer = rpath(fs_ctx, path);
-        tsize = readlink(buffer, buf, bufsz);
-        g_free(buffer);
+        char *dirpath = g_path_get_dirname(fs_path->data);
+        char *name = g_path_get_basename(fs_path->data);
+        int dirfd;
+
+        dirfd = local_opendir_nofollow(fs_ctx, dirpath);
+        if (dirfd == -1) {
+            goto out;
+        }
+
+        tsize = readlinkat(dirfd, name, buf, bufsz);
+        close_preserve_errno(dirfd);
+    out:
+        g_free(name);
+        g_free(dirpath);
     }
     return tsize;
 }
-- 
cgit v1.1


From f9aef99b3e6df88036436b0d3dc3d504b9346c8c Mon Sep 17 00:00:00 2001
From: Greg Kurz <groug@kaod.org>
Date: Sun, 26 Feb 2017 23:43:48 +0100
Subject: 9pfs: local: lstat: don't follow symlinks

The local_lstat() callback is vulnerable to symlink attacks because it
calls:

(1) lstat() which follows symbolic links in all path elements but the
    rightmost one
(2) getxattr() which follows symbolic links in all path elements
(3) local_mapped_file_attr()->local_fopen()->openat(O_NOFOLLOW) which
    follows symbolic links in all path elements but the rightmost
    one

This patch converts local_lstat() to rely on opendir_nofollow() and
fstatat(AT_SYMLINK_NOFOLLOW) to fix (1), fgetxattrat_nofollow() to
fix (2).

A new local_fopenat() helper is introduced as a replacement to
local_fopen() to fix (3). No effort is made to factor out code
because local_fopen() will be dropped when all users have been
converted to call local_fopenat().

This partly fixes CVE-2016-9602.

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 hw/9pfs/9p-local.c | 78 ++++++++++++++++++++++++++++++++++++++++++------------
 1 file changed, 61 insertions(+), 17 deletions(-)

(limited to 'hw')

diff --git a/hw/9pfs/9p-local.c b/hw/9pfs/9p-local.c
index e373cca..b810c64 100644
--- a/hw/9pfs/9p-local.c
+++ b/hw/9pfs/9p-local.c
@@ -111,17 +111,49 @@ static FILE *local_fopen(const char *path, const char *mode)
     return fp;
 }
 
+static FILE *local_fopenat(int dirfd, const char *name, const char *mode)
+{
+    int fd, o_mode = 0;
+    FILE *fp;
+    int flags;
+    /*
+     * only supports two modes
+     */
+    if (mode[0] == 'r') {
+        flags = O_RDONLY;
+    } else if (mode[0] == 'w') {
+        flags = O_WRONLY | O_TRUNC | O_CREAT;
+        o_mode = S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH;
+    } else {
+        return NULL;
+    }
+    fd = openat_file(dirfd, name, flags, o_mode);
+    if (fd == -1) {
+        return NULL;
+    }
+    fp = fdopen(fd, mode);
+    if (!fp) {
+        close(fd);
+    }
+    return fp;
+}
+
 #define ATTR_MAX 100
-static void local_mapped_file_attr(FsContext *ctx, const char *path,
+static void local_mapped_file_attr(int dirfd, const char *name,
                                    struct stat *stbuf)
 {
     FILE *fp;
     char buf[ATTR_MAX];
-    char *attr_path;
+    int map_dirfd;
 
-    attr_path = local_mapped_attr_path(ctx, path);
-    fp = local_fopen(attr_path, "r");
-    g_free(attr_path);
+    map_dirfd = openat(dirfd, VIRTFS_META_DIR,
+                       O_RDONLY | O_DIRECTORY | O_NOFOLLOW);
+    if (map_dirfd == -1) {
+        return;
+    }
+
+    fp = local_fopenat(map_dirfd, name, "r");
+    close_preserve_errno(map_dirfd);
     if (!fp) {
         return;
     }
@@ -143,12 +175,17 @@ static void local_mapped_file_attr(FsContext *ctx, const char *path,
 
 static int local_lstat(FsContext *fs_ctx, V9fsPath *fs_path, struct stat *stbuf)
 {
-    int err;
-    char *buffer;
-    char *path = fs_path->data;
+    int err = -1;
+    char *dirpath = g_path_get_dirname(fs_path->data);
+    char *name = g_path_get_basename(fs_path->data);
+    int dirfd;
 
-    buffer = rpath(fs_ctx, path);
-    err =  lstat(buffer, stbuf);
+    dirfd = local_opendir_nofollow(fs_ctx, dirpath);
+    if (dirfd == -1) {
+        goto out;
+    }
+
+    err = fstatat(dirfd, name, stbuf, AT_SYMLINK_NOFOLLOW);
     if (err) {
         goto err_out;
     }
@@ -158,25 +195,32 @@ static int local_lstat(FsContext *fs_ctx, V9fsPath *fs_path, struct stat *stbuf)
         gid_t tmp_gid;
         mode_t tmp_mode;
         dev_t tmp_dev;
-        if (getxattr(buffer, "user.virtfs.uid", &tmp_uid, sizeof(uid_t)) > 0) {
+
+        if (fgetxattrat_nofollow(dirfd, name, "user.virtfs.uid", &tmp_uid,
+                                 sizeof(uid_t)) > 0) {
             stbuf->st_uid = le32_to_cpu(tmp_uid);
         }
-        if (getxattr(buffer, "user.virtfs.gid", &tmp_gid, sizeof(gid_t)) > 0) {
+        if (fgetxattrat_nofollow(dirfd, name, "user.virtfs.gid", &tmp_gid,
+                                 sizeof(gid_t)) > 0) {
             stbuf->st_gid = le32_to_cpu(tmp_gid);
         }
-        if (getxattr(buffer, "user.virtfs.mode",
-                    &tmp_mode, sizeof(mode_t)) > 0) {
+        if (fgetxattrat_nofollow(dirfd, name, "user.virtfs.mode", &tmp_mode,
+                                 sizeof(mode_t)) > 0) {
             stbuf->st_mode = le32_to_cpu(tmp_mode);
         }
-        if (getxattr(buffer, "user.virtfs.rdev", &tmp_dev, sizeof(dev_t)) > 0) {
+        if (fgetxattrat_nofollow(dirfd, name, "user.virtfs.rdev", &tmp_dev,
+                                 sizeof(dev_t)) > 0) {
             stbuf->st_rdev = le64_to_cpu(tmp_dev);
         }
     } else if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) {
-        local_mapped_file_attr(fs_ctx, path, stbuf);
+        local_mapped_file_attr(dirfd, name, stbuf);
     }
 
 err_out:
-    g_free(buffer);
+    close_preserve_errno(dirfd);
+out:
+    g_free(name);
+    g_free(dirpath);
     return err;
 }
 
-- 
cgit v1.1


From 99f2cf4b2dad7b37c69759deb0d0b19d3ec1a24a Mon Sep 17 00:00:00 2001
From: Greg Kurz <groug@kaod.org>
Date: Sun, 26 Feb 2017 23:43:55 +0100
Subject: 9pfs: local: renameat: don't follow symlinks

The local_renameat() callback is currently a wrapper around local_rename()
which is vulnerable to symlink attacks.

This patch rewrites local_renameat() to have its own implementation, based
on local_opendir_nofollow() and renameat().

This partly fixes CVE-2016-9602.

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 hw/9pfs/9p-local.c | 74 ++++++++++++++++++++++++++++++++++++++++++++++--------
 1 file changed, 64 insertions(+), 10 deletions(-)

(limited to 'hw')

diff --git a/hw/9pfs/9p-local.c b/hw/9pfs/9p-local.c
index b810c64..1136562 100644
--- a/hw/9pfs/9p-local.c
+++ b/hw/9pfs/9p-local.c
@@ -67,6 +67,14 @@ int local_opendir_nofollow(FsContext *fs_ctx, const char *path)
     return local_open_nofollow(fs_ctx, path, O_DIRECTORY | O_RDONLY, 0);
 }
 
+static void renameat_preserve_errno(int odirfd, const char *opath, int ndirfd,
+                                    const char *npath)
+{
+    int serrno = errno;
+    renameat(odirfd, opath, ndirfd, npath);
+    errno = serrno;
+}
+
 #define VIRTFS_META_DIR ".virtfs_metadata"
 
 static char *local_mapped_attr_path(FsContext *ctx, const char *path)
@@ -146,8 +154,7 @@ static void local_mapped_file_attr(int dirfd, const char *name,
     char buf[ATTR_MAX];
     int map_dirfd;
 
-    map_dirfd = openat(dirfd, VIRTFS_META_DIR,
-                       O_RDONLY | O_DIRECTORY | O_NOFOLLOW);
+    map_dirfd = openat_dir(dirfd, VIRTFS_META_DIR);
     if (map_dirfd == -1) {
         return;
     }
@@ -1186,17 +1193,64 @@ static int local_renameat(FsContext *ctx, V9fsPath *olddir,
                           const char *new_name)
 {
     int ret;
-    V9fsString old_full_name, new_full_name;
+    int odirfd, ndirfd;
+
+    odirfd = local_opendir_nofollow(ctx, olddir->data);
+    if (odirfd == -1) {
+        return -1;
+    }
+
+    ndirfd = local_opendir_nofollow(ctx, newdir->data);
+    if (ndirfd == -1) {
+        close_preserve_errno(odirfd);
+        return -1;
+    }
+
+    ret = renameat(odirfd, old_name, ndirfd, new_name);
+    if (ret < 0) {
+        goto out;
+    }
 
-    v9fs_string_init(&old_full_name);
-    v9fs_string_init(&new_full_name);
+    if (ctx->export_flags & V9FS_SM_MAPPED_FILE) {
+        int omap_dirfd, nmap_dirfd;
 
-    v9fs_string_sprintf(&old_full_name, "%s/%s", olddir->data, old_name);
-    v9fs_string_sprintf(&new_full_name, "%s/%s", newdir->data, new_name);
+        ret = mkdirat(ndirfd, VIRTFS_META_DIR, 0700);
+        if (ret < 0 && errno != EEXIST) {
+            goto err_undo_rename;
+        }
 
-    ret = local_rename(ctx, old_full_name.data, new_full_name.data);
-    v9fs_string_free(&old_full_name);
-    v9fs_string_free(&new_full_name);
+        omap_dirfd = openat(odirfd, VIRTFS_META_DIR,
+                            O_RDONLY | O_DIRECTORY | O_NOFOLLOW);
+        if (omap_dirfd == -1) {
+            goto err;
+        }
+
+        nmap_dirfd = openat(ndirfd, VIRTFS_META_DIR,
+                            O_RDONLY | O_DIRECTORY | O_NOFOLLOW);
+        if (nmap_dirfd == -1) {
+            close_preserve_errno(omap_dirfd);
+            goto err;
+        }
+
+        /* rename the .virtfs_metadata files */
+        ret = renameat(omap_dirfd, old_name, nmap_dirfd, new_name);
+        close_preserve_errno(nmap_dirfd);
+        close_preserve_errno(omap_dirfd);
+        if (ret < 0 && errno != ENOENT) {
+            goto err_undo_rename;
+        }
+
+        ret = 0;
+    }
+    goto out;
+
+err:
+    ret = -1;
+err_undo_rename:
+    renameat_preserve_errno(ndirfd, new_name, odirfd, old_name);
+out:
+    close_preserve_errno(ndirfd);
+    close_preserve_errno(odirfd);
     return ret;
 }
 
-- 
cgit v1.1


From d2767edec582558f1e6c52e1dd9370d62e2b30fc Mon Sep 17 00:00:00 2001
From: Greg Kurz <groug@kaod.org>
Date: Sun, 26 Feb 2017 23:44:03 +0100
Subject: 9pfs: local: rename: use renameat

The local_rename() callback is vulnerable to symlink attacks because it
uses rename() which follows symbolic links in all path elements but the
rightmost one.

This patch simply transforms local_rename() into a wrapper around
local_renameat() which is symlink-attack safe.

This partly fixes CVE-2016-9602.

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 hw/9pfs/9p-local.c | 57 ++++++++++++++++++++++++++----------------------------
 1 file changed, 27 insertions(+), 30 deletions(-)

(limited to 'hw')

diff --git a/hw/9pfs/9p-local.c b/hw/9pfs/9p-local.c
index 1136562..77f79b6 100644
--- a/hw/9pfs/9p-local.c
+++ b/hw/9pfs/9p-local.c
@@ -964,36 +964,6 @@ static int local_truncate(FsContext *ctx, V9fsPath *fs_path, off_t size)
     return ret;
 }
 
-static int local_rename(FsContext *ctx, const char *oldpath,
-                        const char *newpath)
-{
-    int err;
-    char *buffer, *buffer1;
-
-    if (ctx->export_flags & V9FS_SM_MAPPED_FILE) {
-        err = local_create_mapped_attr_dir(ctx, newpath);
-        if (err < 0) {
-            return err;
-        }
-        /* rename the .virtfs_metadata files */
-        buffer = local_mapped_attr_path(ctx, oldpath);
-        buffer1 = local_mapped_attr_path(ctx, newpath);
-        err = rename(buffer, buffer1);
-        g_free(buffer);
-        g_free(buffer1);
-        if (err < 0 && errno != ENOENT) {
-            return err;
-        }
-    }
-
-    buffer = rpath(ctx, oldpath);
-    buffer1 = rpath(ctx, newpath);
-    err = rename(buffer, buffer1);
-    g_free(buffer);
-    g_free(buffer1);
-    return err;
-}
-
 static int local_chown(FsContext *fs_ctx, V9fsPath *fs_path, FsCred *credp)
 {
     char *buffer;
@@ -1254,6 +1224,33 @@ out:
     return ret;
 }
 
+static void v9fs_path_init_dirname(V9fsPath *path, const char *str)
+{
+    path->data = g_path_get_dirname(str);
+    path->size = strlen(path->data) + 1;
+}
+
+static int local_rename(FsContext *ctx, const char *oldpath,
+                        const char *newpath)
+{
+    int err;
+    char *oname = g_path_get_basename(oldpath);
+    char *nname = g_path_get_basename(newpath);
+    V9fsPath olddir, newdir;
+
+    v9fs_path_init_dirname(&olddir, oldpath);
+    v9fs_path_init_dirname(&newdir, newpath);
+
+    err = local_renameat(ctx, &olddir, oname, &newdir, nname);
+
+    v9fs_path_free(&newdir);
+    v9fs_path_free(&olddir);
+    g_free(nname);
+    g_free(oname);
+
+    return err;
+}
+
 static int local_unlinkat(FsContext *ctx, V9fsPath *dir,
                           const char *name, int flags)
 {
-- 
cgit v1.1


From 6dd4b1f1d026e478d9177b28169b377e212400f3 Mon Sep 17 00:00:00 2001
From: Greg Kurz <groug@kaod.org>
Date: Sun, 26 Feb 2017 23:44:11 +0100
Subject: 9pfs: local: improve error handling in link op

When using the mapped-file security model, we also have to create a link
for the metadata file if it exists. In case of failure, we should rollback.

That's what this patch does.

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 hw/9pfs/9p-local.c | 32 +++++++++++++++++++++-----------
 1 file changed, 21 insertions(+), 11 deletions(-)

(limited to 'hw')

diff --git a/hw/9pfs/9p-local.c b/hw/9pfs/9p-local.c
index 77f79b6..2538bd3 100644
--- a/hw/9pfs/9p-local.c
+++ b/hw/9pfs/9p-local.c
@@ -920,6 +920,7 @@ static int local_link(FsContext *ctx, V9fsPath *oldpath,
     int ret;
     V9fsString newpath;
     char *buffer, *buffer1;
+    int serrno;
 
     v9fs_string_init(&newpath);
     v9fs_string_sprintf(&newpath, "%s/%s", dirpath->data, name);
@@ -928,25 +929,36 @@ static int local_link(FsContext *ctx, V9fsPath *oldpath,
     buffer1 = rpath(ctx, newpath.data);
     ret = link(buffer, buffer1);
     g_free(buffer);
-    g_free(buffer1);
+    if (ret < 0) {
+        goto out;
+    }
 
     /* now link the virtfs_metadata files */
-    if (!ret && (ctx->export_flags & V9FS_SM_MAPPED_FILE)) {
+    if (ctx->export_flags & V9FS_SM_MAPPED_FILE) {
+        char *vbuffer, *vbuffer1;
+
         /* Link the .virtfs_metadata files. Create the metada directory */
         ret = local_create_mapped_attr_dir(ctx, newpath.data);
         if (ret < 0) {
             goto err_out;
         }
-        buffer = local_mapped_attr_path(ctx, oldpath->data);
-        buffer1 = local_mapped_attr_path(ctx, newpath.data);
-        ret = link(buffer, buffer1);
-        g_free(buffer);
-        g_free(buffer1);
+        vbuffer = local_mapped_attr_path(ctx, oldpath->data);
+        vbuffer1 = local_mapped_attr_path(ctx, newpath.data);
+        ret = link(vbuffer, vbuffer1);
+        g_free(vbuffer);
+        g_free(vbuffer1);
         if (ret < 0 && errno != ENOENT) {
             goto err_out;
         }
     }
+    goto out;
+
 err_out:
+    serrno = errno;
+    remove(buffer1);
+    errno = serrno;
+out:
+    g_free(buffer1);
     v9fs_string_free(&newpath);
     return ret;
 }
@@ -1189,14 +1201,12 @@ static int local_renameat(FsContext *ctx, V9fsPath *olddir,
             goto err_undo_rename;
         }
 
-        omap_dirfd = openat(odirfd, VIRTFS_META_DIR,
-                            O_RDONLY | O_DIRECTORY | O_NOFOLLOW);
+        omap_dirfd = openat_dir(odirfd, VIRTFS_META_DIR);
         if (omap_dirfd == -1) {
             goto err;
         }
 
-        nmap_dirfd = openat(ndirfd, VIRTFS_META_DIR,
-                            O_RDONLY | O_DIRECTORY | O_NOFOLLOW);
+        nmap_dirfd = openat_dir(ndirfd, VIRTFS_META_DIR);
         if (nmap_dirfd == -1) {
             close_preserve_errno(omap_dirfd);
             goto err;
-- 
cgit v1.1


From ad0b46e6ac769b187cb4dcf0065675ef8a198a5e Mon Sep 17 00:00:00 2001
From: Greg Kurz <groug@kaod.org>
Date: Sun, 26 Feb 2017 23:44:20 +0100
Subject: 9pfs: local: link: don't follow symlinks

The local_link() callback is vulnerable to symlink attacks because it calls:

(1) link() which follows symbolic links for all path elements but the
    rightmost one
(2) local_create_mapped_attr_dir()->mkdir() which follows symbolic links
    for all path elements but the rightmost one

This patch converts local_link() to rely on opendir_nofollow() and linkat()
to fix (1), mkdirat() to fix (2).

This partly fixes CVE-2016-9602.

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 hw/9pfs/9p-local.c | 84 +++++++++++++++++++++++++++++++++++-------------------
 1 file changed, 55 insertions(+), 29 deletions(-)

(limited to 'hw')

diff --git a/hw/9pfs/9p-local.c b/hw/9pfs/9p-local.c
index 2538bd3..2c38ea1 100644
--- a/hw/9pfs/9p-local.c
+++ b/hw/9pfs/9p-local.c
@@ -75,6 +75,13 @@ static void renameat_preserve_errno(int odirfd, const char *opath, int ndirfd,
     errno = serrno;
 }
 
+static void unlinkat_preserve_errno(int dirfd, const char *path, int flags)
+{
+    int serrno = errno;
+    unlinkat(dirfd, path, flags);
+    errno = serrno;
+}
+
 #define VIRTFS_META_DIR ".virtfs_metadata"
 
 static char *local_mapped_attr_path(FsContext *ctx, const char *path)
@@ -917,49 +924,68 @@ out:
 static int local_link(FsContext *ctx, V9fsPath *oldpath,
                       V9fsPath *dirpath, const char *name)
 {
-    int ret;
-    V9fsString newpath;
-    char *buffer, *buffer1;
-    int serrno;
+    char *odirpath = g_path_get_dirname(oldpath->data);
+    char *oname = g_path_get_basename(oldpath->data);
+    int ret = -1;
+    int odirfd, ndirfd;
 
-    v9fs_string_init(&newpath);
-    v9fs_string_sprintf(&newpath, "%s/%s", dirpath->data, name);
+    odirfd = local_opendir_nofollow(ctx, odirpath);
+    if (odirfd == -1) {
+        goto out;
+    }
 
-    buffer = rpath(ctx, oldpath->data);
-    buffer1 = rpath(ctx, newpath.data);
-    ret = link(buffer, buffer1);
-    g_free(buffer);
-    if (ret < 0) {
+    ndirfd = local_opendir_nofollow(ctx, dirpath->data);
+    if (ndirfd == -1) {
+        close_preserve_errno(odirfd);
         goto out;
     }
 
+    ret = linkat(odirfd, oname, ndirfd, name, 0);
+    if (ret < 0) {
+        goto out_close;
+    }
+
     /* now link the virtfs_metadata files */
     if (ctx->export_flags & V9FS_SM_MAPPED_FILE) {
-        char *vbuffer, *vbuffer1;
+        int omap_dirfd, nmap_dirfd;
 
-        /* Link the .virtfs_metadata files. Create the metada directory */
-        ret = local_create_mapped_attr_dir(ctx, newpath.data);
-        if (ret < 0) {
-            goto err_out;
+        ret = mkdirat(ndirfd, VIRTFS_META_DIR, 0700);
+        if (ret < 0 && errno != EEXIST) {
+            goto err_undo_link;
         }
-        vbuffer = local_mapped_attr_path(ctx, oldpath->data);
-        vbuffer1 = local_mapped_attr_path(ctx, newpath.data);
-        ret = link(vbuffer, vbuffer1);
-        g_free(vbuffer);
-        g_free(vbuffer1);
+
+        omap_dirfd = openat_dir(odirfd, VIRTFS_META_DIR);
+        if (omap_dirfd == -1) {
+            goto err;
+        }
+
+        nmap_dirfd = openat_dir(ndirfd, VIRTFS_META_DIR);
+        if (nmap_dirfd == -1) {
+            close_preserve_errno(omap_dirfd);
+            goto err;
+        }
+
+        ret = linkat(omap_dirfd, oname, nmap_dirfd, name, 0);
+        close_preserve_errno(nmap_dirfd);
+        close_preserve_errno(omap_dirfd);
         if (ret < 0 && errno != ENOENT) {
-            goto err_out;
+            goto err_undo_link;
         }
+
+        ret = 0;
     }
-    goto out;
+    goto out_close;
 
-err_out:
-    serrno = errno;
-    remove(buffer1);
-    errno = serrno;
+err:
+    ret = -1;
+err_undo_link:
+    unlinkat_preserve_errno(ndirfd, name, 0);
+out_close:
+    close_preserve_errno(ndirfd);
+    close_preserve_errno(odirfd);
 out:
-    g_free(buffer1);
-    v9fs_string_free(&newpath);
+    g_free(oname);
+    g_free(odirpath);
     return ret;
 }
 
-- 
cgit v1.1


From e3187a45dd02a7490f9191c16527dc28a4ba45b9 Mon Sep 17 00:00:00 2001
From: Greg Kurz <groug@kaod.org>
Date: Sun, 26 Feb 2017 23:44:28 +0100
Subject: 9pfs: local: chmod: don't follow symlinks

The local_chmod() callback is vulnerable to symlink attacks because it
calls:

(1) chmod() which follows symbolic links for all path elements
(2) local_set_xattr()->setxattr() which follows symbolic links for all
    path elements
(3) local_set_mapped_file_attr() which calls in turn local_fopen() and
    mkdir(), both functions following symbolic links for all path
    elements but the rightmost one

We would need fchmodat() to implement AT_SYMLINK_NOFOLLOW to fix (1). This
isn't the case on linux unfortunately: the kernel doesn't even have a flags
argument to the syscall :-\ It is impossible to fix it in userspace in
a race-free manner. This patch hence converts local_chmod() to rely on
open_nofollow() and fchmod(). This fixes the vulnerability but introduces
a limitation: the target file must readable and/or writable for the call
to openat() to succeed.

It introduces a local_set_xattrat() replacement to local_set_xattr()
based on fsetxattrat() to fix (2), and a local_set_mapped_file_attrat()
replacement to local_set_mapped_file_attr() based on local_fopenat()
and mkdirat() to fix (3). No effort is made to factor out code because
both local_set_xattr() and local_set_mapped_file_attr() will be dropped
when all users have been converted to use the "at" versions.

This partly fixes CVE-2016-9602.

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 hw/9pfs/9p-local.c | 178 +++++++++++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 167 insertions(+), 11 deletions(-)

(limited to 'hw')

diff --git a/hw/9pfs/9p-local.c b/hw/9pfs/9p-local.c
index 2c38ea1..27ecbf6 100644
--- a/hw/9pfs/9p-local.c
+++ b/hw/9pfs/9p-local.c
@@ -367,6 +367,155 @@ static int local_set_xattr(const char *path, FsCred *credp)
     return 0;
 }
 
+static int local_set_mapped_file_attrat(int dirfd, const char *name,
+                                        FsCred *credp)
+{
+    FILE *fp;
+    int ret;
+    char buf[ATTR_MAX];
+    int uid = -1, gid = -1, mode = -1, rdev = -1;
+    int map_dirfd;
+
+    ret = mkdirat(dirfd, VIRTFS_META_DIR, 0700);
+    if (ret < 0 && errno != EEXIST) {
+        return -1;
+    }
+
+    map_dirfd = openat_dir(dirfd, VIRTFS_META_DIR);
+    if (map_dirfd == -1) {
+        return -1;
+    }
+
+    fp = local_fopenat(map_dirfd, name, "r");
+    if (!fp) {
+        if (errno == ENOENT) {
+            goto update_map_file;
+        } else {
+            close_preserve_errno(map_dirfd);
+            return -1;
+        }
+    }
+    memset(buf, 0, ATTR_MAX);
+    while (fgets(buf, ATTR_MAX, fp)) {
+        if (!strncmp(buf, "virtfs.uid", 10)) {
+            uid = atoi(buf + 11);
+        } else if (!strncmp(buf, "virtfs.gid", 10)) {
+            gid = atoi(buf + 11);
+        } else if (!strncmp(buf, "virtfs.mode", 11)) {
+            mode = atoi(buf + 12);
+        } else if (!strncmp(buf, "virtfs.rdev", 11)) {
+            rdev = atoi(buf + 12);
+        }
+        memset(buf, 0, ATTR_MAX);
+    }
+    fclose(fp);
+
+update_map_file:
+    fp = local_fopenat(map_dirfd, name, "w");
+    close_preserve_errno(map_dirfd);
+    if (!fp) {
+        return -1;
+    }
+
+    if (credp->fc_uid != -1) {
+        uid = credp->fc_uid;
+    }
+    if (credp->fc_gid != -1) {
+        gid = credp->fc_gid;
+    }
+    if (credp->fc_mode != -1) {
+        mode = credp->fc_mode;
+    }
+    if (credp->fc_rdev != -1) {
+        rdev = credp->fc_rdev;
+    }
+
+    if (uid != -1) {
+        fprintf(fp, "virtfs.uid=%d\n", uid);
+    }
+    if (gid != -1) {
+        fprintf(fp, "virtfs.gid=%d\n", gid);
+    }
+    if (mode != -1) {
+        fprintf(fp, "virtfs.mode=%d\n", mode);
+    }
+    if (rdev != -1) {
+        fprintf(fp, "virtfs.rdev=%d\n", rdev);
+    }
+    fclose(fp);
+
+    return 0;
+}
+
+static int fchmodat_nofollow(int dirfd, const char *name, mode_t mode)
+{
+    int fd, ret;
+
+    /* FIXME: this should be handled with fchmodat(AT_SYMLINK_NOFOLLOW).
+     * Unfortunately, the linux kernel doesn't implement it yet. As an
+     * alternative, let's open the file and use fchmod() instead. This
+     * may fail depending on the permissions of the file, but it is the
+     * best we can do to avoid TOCTTOU. We first try to open read-only
+     * in case name points to a directory. If that fails, we try write-only
+     * in case name doesn't point to a directory.
+     */
+    fd = openat_file(dirfd, name, O_RDONLY, 0);
+    if (fd == -1) {
+        /* In case the file is writable-only and isn't a directory. */
+        if (errno == EACCES) {
+            fd = openat_file(dirfd, name, O_WRONLY, 0);
+        }
+        if (fd == -1 && errno == EISDIR) {
+            errno = EACCES;
+        }
+    }
+    if (fd == -1) {
+        return -1;
+    }
+    ret = fchmod(fd, mode);
+    close_preserve_errno(fd);
+    return ret;
+}
+
+static int local_set_xattrat(int dirfd, const char *path, FsCred *credp)
+{
+    int err;
+
+    if (credp->fc_uid != -1) {
+        uint32_t tmp_uid = cpu_to_le32(credp->fc_uid);
+        err = fsetxattrat_nofollow(dirfd, path, "user.virtfs.uid", &tmp_uid,
+                                   sizeof(uid_t), 0);
+        if (err) {
+            return err;
+        }
+    }
+    if (credp->fc_gid != -1) {
+        uint32_t tmp_gid = cpu_to_le32(credp->fc_gid);
+        err = fsetxattrat_nofollow(dirfd, path, "user.virtfs.gid", &tmp_gid,
+                                   sizeof(gid_t), 0);
+        if (err) {
+            return err;
+        }
+    }
+    if (credp->fc_mode != -1) {
+        uint32_t tmp_mode = cpu_to_le32(credp->fc_mode);
+        err = fsetxattrat_nofollow(dirfd, path, "user.virtfs.mode", &tmp_mode,
+                                   sizeof(mode_t), 0);
+        if (err) {
+            return err;
+        }
+    }
+    if (credp->fc_rdev != -1) {
+        uint64_t tmp_rdev = cpu_to_le64(credp->fc_rdev);
+        err = fsetxattrat_nofollow(dirfd, path, "user.virtfs.rdev", &tmp_rdev,
+                                   sizeof(dev_t), 0);
+        if (err) {
+            return err;
+        }
+    }
+    return 0;
+}
+
 static int local_post_create_passthrough(FsContext *fs_ctx, const char *path,
                                          FsCred *credp)
 {
@@ -558,22 +707,29 @@ static ssize_t local_pwritev(FsContext *ctx, V9fsFidOpenState *fs,
 
 static int local_chmod(FsContext *fs_ctx, V9fsPath *fs_path, FsCred *credp)
 {
-    char *buffer;
+    char *dirpath = g_path_get_dirname(fs_path->data);
+    char *name = g_path_get_basename(fs_path->data);
     int ret = -1;
-    char *path = fs_path->data;
+    int dirfd;
+
+    dirfd = local_opendir_nofollow(fs_ctx, dirpath);
+    if (dirfd == -1) {
+        goto out;
+    }
 
     if (fs_ctx->export_flags & V9FS_SM_MAPPED) {
-        buffer = rpath(fs_ctx, path);
-        ret = local_set_xattr(buffer, credp);
-        g_free(buffer);
+        ret = local_set_xattrat(dirfd, name, credp);
     } else if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) {
-        return local_set_mapped_file_attr(fs_ctx, path, credp);
-    } else if ((fs_ctx->export_flags & V9FS_SM_PASSTHROUGH) ||
-               (fs_ctx->export_flags & V9FS_SM_NONE)) {
-        buffer = rpath(fs_ctx, path);
-        ret = chmod(buffer, credp->fc_mode);
-        g_free(buffer);
+        ret = local_set_mapped_file_attrat(dirfd, name, credp);
+    } else if (fs_ctx->export_flags & V9FS_SM_PASSTHROUGH ||
+               fs_ctx->export_flags & V9FS_SM_NONE) {
+        ret = fchmodat_nofollow(dirfd, name, credp->fc_mode);
     }
+    close_preserve_errno(dirfd);
+
+out:
+    g_free(dirpath);
+    g_free(name);
     return ret;
 }
 
-- 
cgit v1.1


From d369f20763a857eac544a5289a046d0285a91df8 Mon Sep 17 00:00:00 2001
From: Greg Kurz <groug@kaod.org>
Date: Sun, 26 Feb 2017 23:44:37 +0100
Subject: 9pfs: local: chown: don't follow symlinks

The local_chown() callback is vulnerable to symlink attacks because it
calls:

(1) lchown() which follows symbolic links for all path elements but the
    rightmost one
(2) local_set_xattr()->setxattr() which follows symbolic links for all
    path elements
(3) local_set_mapped_file_attr() which calls in turn local_fopen() and
    mkdir(), both functions following symbolic links for all path
    elements but the rightmost one

This patch converts local_chown() to rely on open_nofollow() and
fchownat() to fix (1), as well as local_set_xattrat() and
local_set_mapped_file_attrat() to fix (2) and (3) respectively.

This partly fixes CVE-2016-9602.

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 hw/9pfs/9p-local.c | 26 +++++++++++++++++---------
 1 file changed, 17 insertions(+), 9 deletions(-)

(limited to 'hw')

diff --git a/hw/9pfs/9p-local.c b/hw/9pfs/9p-local.c
index 27ecbf6..2cd3962 100644
--- a/hw/9pfs/9p-local.c
+++ b/hw/9pfs/9p-local.c
@@ -1160,23 +1160,31 @@ static int local_truncate(FsContext *ctx, V9fsPath *fs_path, off_t size)
 
 static int local_chown(FsContext *fs_ctx, V9fsPath *fs_path, FsCred *credp)
 {
-    char *buffer;
+    char *dirpath = g_path_get_dirname(fs_path->data);
+    char *name = g_path_get_basename(fs_path->data);
     int ret = -1;
-    char *path = fs_path->data;
+    int dirfd;
+
+    dirfd = local_opendir_nofollow(fs_ctx, dirpath);
+    if (dirfd == -1) {
+        goto out;
+    }
 
     if ((credp->fc_uid == -1 && credp->fc_gid == -1) ||
         (fs_ctx->export_flags & V9FS_SM_PASSTHROUGH) ||
         (fs_ctx->export_flags & V9FS_SM_NONE)) {
-        buffer = rpath(fs_ctx, path);
-        ret = lchown(buffer, credp->fc_uid, credp->fc_gid);
-        g_free(buffer);
+        ret = fchownat(dirfd, name, credp->fc_uid, credp->fc_gid,
+                       AT_SYMLINK_NOFOLLOW);
     } else if (fs_ctx->export_flags & V9FS_SM_MAPPED) {
-        buffer = rpath(fs_ctx, path);
-        ret = local_set_xattr(buffer, credp);
-        g_free(buffer);
+        ret = local_set_xattrat(dirfd, name, credp);
     } else if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) {
-        return local_set_mapped_file_attr(fs_ctx, path, credp);
+        ret = local_set_mapped_file_attrat(dirfd, name, credp);
     }
+
+    close_preserve_errno(dirfd);
+out:
+    g_free(name);
+    g_free(dirpath);
     return ret;
 }
 
-- 
cgit v1.1


From 38771613ea6759f499645afd709aa422161eb27e Mon Sep 17 00:00:00 2001
From: Greg Kurz <groug@kaod.org>
Date: Sun, 26 Feb 2017 23:44:46 +0100
Subject: 9pfs: local: symlink: don't follow symlinks

The local_symlink() callback is vulnerable to symlink attacks because it
calls:

(1) symlink() which follows symbolic links for all path elements but the
    rightmost one
(2) open(O_NOFOLLOW) which follows symbolic links for all path elements but
    the rightmost one
(3) local_set_xattr()->setxattr() which follows symbolic links for all
    path elements
(4) local_set_mapped_file_attr() which calls in turn local_fopen() and
    mkdir(), both functions following symbolic links for all path
    elements but the rightmost one

This patch converts local_symlink() to rely on opendir_nofollow() and
symlinkat() to fix (1), openat(O_NOFOLLOW) to fix (2), as well as
local_set_xattrat() and local_set_mapped_file_attrat() to fix (3) and
(4) respectively.

This partly fixes CVE-2016-9602.

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 hw/9pfs/9p-local.c | 81 +++++++++++++++++-------------------------------------
 1 file changed, 25 insertions(+), 56 deletions(-)

(limited to 'hw')

diff --git a/hw/9pfs/9p-local.c b/hw/9pfs/9p-local.c
index 2cd3962..fab9bee 100644
--- a/hw/9pfs/9p-local.c
+++ b/hw/9pfs/9p-local.c
@@ -978,23 +978,22 @@ static int local_symlink(FsContext *fs_ctx, const char *oldpath,
                          V9fsPath *dir_path, const char *name, FsCred *credp)
 {
     int err = -1;
-    int serrno = 0;
-    char *newpath;
-    V9fsString fullname;
-    char *buffer = NULL;
+    int dirfd;
 
-    v9fs_string_init(&fullname);
-    v9fs_string_sprintf(&fullname, "%s/%s", dir_path->data, name);
-    newpath = fullname.data;
+    dirfd = local_opendir_nofollow(fs_ctx, dir_path->data);
+    if (dirfd == -1) {
+        return -1;
+    }
 
     /* Determine the security model */
-    if (fs_ctx->export_flags & V9FS_SM_MAPPED) {
+    if (fs_ctx->export_flags & V9FS_SM_MAPPED ||
+        fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) {
         int fd;
         ssize_t oldpath_size, write_size;
-        buffer = rpath(fs_ctx, newpath);
-        fd = open(buffer, O_CREAT|O_EXCL|O_RDWR|O_NOFOLLOW, SM_LOCAL_MODE_BITS);
+
+        fd = openat_file(dirfd, name, O_CREAT | O_EXCL | O_RDWR,
+                         SM_LOCAL_MODE_BITS);
         if (fd == -1) {
-            err = fd;
             goto out;
         }
         /* Write the oldpath (target) to the file. */
@@ -1002,78 +1001,48 @@ static int local_symlink(FsContext *fs_ctx, const char *oldpath,
         do {
             write_size = write(fd, (void *)oldpath, oldpath_size);
         } while (write_size == -1 && errno == EINTR);
+        close_preserve_errno(fd);
 
         if (write_size != oldpath_size) {
-            serrno = errno;
-            close(fd);
-            err = -1;
             goto err_end;
         }
-        close(fd);
         /* Set cleint credentials in symlink's xattr */
-        credp->fc_mode = credp->fc_mode|S_IFLNK;
-        err = local_set_xattr(buffer, credp);
-        if (err == -1) {
-            serrno = errno;
-            goto err_end;
-        }
-    } else if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) {
-        int fd;
-        ssize_t oldpath_size, write_size;
-        buffer = rpath(fs_ctx, newpath);
-        fd = open(buffer, O_CREAT|O_EXCL|O_RDWR|O_NOFOLLOW, SM_LOCAL_MODE_BITS);
-        if (fd == -1) {
-            err = fd;
-            goto out;
-        }
-        /* Write the oldpath (target) to the file. */
-        oldpath_size = strlen(oldpath);
-        do {
-            write_size = write(fd, (void *)oldpath, oldpath_size);
-        } while (write_size == -1 && errno == EINTR);
+        credp->fc_mode = credp->fc_mode | S_IFLNK;
 
-        if (write_size != oldpath_size) {
-            serrno = errno;
-            close(fd);
-            err = -1;
-            goto err_end;
+        if (fs_ctx->export_flags & V9FS_SM_MAPPED) {
+            err = local_set_xattrat(dirfd, name, credp);
+        } else {
+            err = local_set_mapped_file_attrat(dirfd, name, credp);
         }
-        close(fd);
-        /* Set cleint credentials in symlink's xattr */
-        credp->fc_mode = credp->fc_mode|S_IFLNK;
-        err = local_set_mapped_file_attr(fs_ctx, newpath, credp);
         if (err == -1) {
-            serrno = errno;
             goto err_end;
         }
-    } else if ((fs_ctx->export_flags & V9FS_SM_PASSTHROUGH) ||
-               (fs_ctx->export_flags & V9FS_SM_NONE)) {
-        buffer = rpath(fs_ctx, newpath);
-        err = symlink(oldpath, buffer);
+    } else if (fs_ctx->export_flags & V9FS_SM_PASSTHROUGH ||
+               fs_ctx->export_flags & V9FS_SM_NONE) {
+        err = symlinkat(oldpath, dirfd, name);
         if (err) {
             goto out;
         }
-        err = lchown(buffer, credp->fc_uid, credp->fc_gid);
+        err = fchownat(dirfd, name, credp->fc_uid, credp->fc_gid,
+                       AT_SYMLINK_NOFOLLOW);
         if (err == -1) {
             /*
              * If we fail to change ownership and if we are
              * using security model none. Ignore the error
              */
             if ((fs_ctx->export_flags & V9FS_SEC_MASK) != V9FS_SM_NONE) {
-                serrno = errno;
                 goto err_end;
-            } else
+            } else {
                 err = 0;
+            }
         }
     }
     goto out;
 
 err_end:
-    remove(buffer);
-    errno = serrno;
+    unlinkat_preserve_errno(dirfd, name, 0);
 out:
-    g_free(buffer);
-    v9fs_string_free(&fullname);
+    close_preserve_errno(dirfd);
     return err;
 }
 
-- 
cgit v1.1


From d815e7219036d6911fce12efe3e59906264c8536 Mon Sep 17 00:00:00 2001
From: Greg Kurz <groug@kaod.org>
Date: Sun, 26 Feb 2017 23:44:54 +0100
Subject: 9pfs: local: mknod: don't follow symlinks

The local_mknod() callback is vulnerable to symlink attacks because it
calls:

(1) mknod() which follows symbolic links for all path elements but the
    rightmost one
(2) local_set_xattr()->setxattr() which follows symbolic links for all
    path elements
(3) local_set_mapped_file_attr() which calls in turn local_fopen() and
    mkdir(), both functions following symbolic links for all path
    elements but the rightmost one
(4) local_post_create_passthrough() which calls in turn lchown() and
    chmod(), both functions also following symbolic links

This patch converts local_mknod() to rely on opendir_nofollow() and
mknodat() to fix (1), as well as local_set_xattrat() and
local_set_mapped_file_attrat() to fix (2) and (3) respectively.

A new local_set_cred_passthrough() helper based on fchownat() and
fchmodat_nofollow() is introduced as a replacement to
local_post_create_passthrough() to fix (4).

The mapped and mapped-file security modes are supposed to be identical,
except for the place where credentials and file modes are stored. While
here, we also make that explicit by sharing the call to mknodat().

This partly fixes CVE-2016-9602.

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 hw/9pfs/9p-local.c | 68 ++++++++++++++++++++++++++++--------------------------
 1 file changed, 35 insertions(+), 33 deletions(-)

(limited to 'hw')

diff --git a/hw/9pfs/9p-local.c b/hw/9pfs/9p-local.c
index fab9bee..db70c2d 100644
--- a/hw/9pfs/9p-local.c
+++ b/hw/9pfs/9p-local.c
@@ -543,6 +543,23 @@ err:
     return -1;
 }
 
+static int local_set_cred_passthrough(FsContext *fs_ctx, int dirfd,
+                                      const char *name, FsCred *credp)
+{
+    if (fchownat(dirfd, name, credp->fc_uid, credp->fc_gid,
+                 AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH) < 0) {
+        /*
+         * If we fail to change ownership and if we are
+         * using security model none. Ignore the error
+         */
+        if ((fs_ctx->export_flags & V9FS_SEC_MASK) != V9FS_SM_NONE) {
+            return -1;
+        }
+    }
+
+    return fchmodat_nofollow(dirfd, name, credp->fc_mode & 07777);
+}
+
 static ssize_t local_readlink(FsContext *fs_ctx, V9fsPath *fs_path,
                               char *buf, size_t bufsz)
 {
@@ -736,61 +753,46 @@ out:
 static int local_mknod(FsContext *fs_ctx, V9fsPath *dir_path,
                        const char *name, FsCred *credp)
 {
-    char *path;
     int err = -1;
-    int serrno = 0;
-    V9fsString fullname;
-    char *buffer = NULL;
+    int dirfd;
 
-    v9fs_string_init(&fullname);
-    v9fs_string_sprintf(&fullname, "%s/%s", dir_path->data, name);
-    path = fullname.data;
+    dirfd = local_opendir_nofollow(fs_ctx, dir_path->data);
+    if (dirfd == -1) {
+        return -1;
+    }
 
-    /* Determine the security model */
-    if (fs_ctx->export_flags & V9FS_SM_MAPPED) {
-        buffer = rpath(fs_ctx, path);
-        err = mknod(buffer, SM_LOCAL_MODE_BITS|S_IFREG, 0);
+    if (fs_ctx->export_flags & V9FS_SM_MAPPED ||
+        fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) {
+        err = mknodat(dirfd, name, SM_LOCAL_MODE_BITS | S_IFREG, 0);
         if (err == -1) {
             goto out;
         }
-        err = local_set_xattr(buffer, credp);
-        if (err == -1) {
-            serrno = errno;
-            goto err_end;
-        }
-    } else if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) {
 
-        buffer = rpath(fs_ctx, path);
-        err = mknod(buffer, SM_LOCAL_MODE_BITS|S_IFREG, 0);
-        if (err == -1) {
-            goto out;
+        if (fs_ctx->export_flags & V9FS_SM_MAPPED) {
+            err = local_set_xattrat(dirfd, name, credp);
+        } else {
+            err = local_set_mapped_file_attrat(dirfd, name, credp);
         }
-        err = local_set_mapped_file_attr(fs_ctx, path, credp);
         if (err == -1) {
-            serrno = errno;
             goto err_end;
         }
-    } else if ((fs_ctx->export_flags & V9FS_SM_PASSTHROUGH) ||
-               (fs_ctx->export_flags & V9FS_SM_NONE)) {
-        buffer = rpath(fs_ctx, path);
-        err = mknod(buffer, credp->fc_mode, credp->fc_rdev);
+    } else if (fs_ctx->export_flags & V9FS_SM_PASSTHROUGH ||
+               fs_ctx->export_flags & V9FS_SM_NONE) {
+        err = mknodat(dirfd, name, credp->fc_mode, credp->fc_rdev);
         if (err == -1) {
             goto out;
         }
-        err = local_post_create_passthrough(fs_ctx, path, credp);
+        err = local_set_cred_passthrough(fs_ctx, dirfd, name, credp);
         if (err == -1) {
-            serrno = errno;
             goto err_end;
         }
     }
     goto out;
 
 err_end:
-    remove(buffer);
-    errno = serrno;
+    unlinkat_preserve_errno(dirfd, name, 0);
 out:
-    g_free(buffer);
-    v9fs_string_free(&fullname);
+    close_preserve_errno(dirfd);
     return err;
 }
 
-- 
cgit v1.1


From 3f3a16990b09e62d787bd2eb2dd51aafbe90019a Mon Sep 17 00:00:00 2001
From: Greg Kurz <groug@kaod.org>
Date: Sun, 26 Feb 2017 23:45:02 +0100
Subject: 9pfs: local: mkdir: don't follow symlinks

The local_mkdir() callback is vulnerable to symlink attacks because it
calls:

(1) mkdir() which follows symbolic links for all path elements but the
    rightmost one
(2) local_set_xattr()->setxattr() which follows symbolic links for all
    path elements
(3) local_set_mapped_file_attr() which calls in turn local_fopen() and
    mkdir(), both functions following symbolic links for all path
    elements but the rightmost one
(4) local_post_create_passthrough() which calls in turn lchown() and
    chmod(), both functions also following symbolic links

This patch converts local_mkdir() to rely on opendir_nofollow() and
mkdirat() to fix (1), as well as local_set_xattrat(),
local_set_mapped_file_attrat() and local_set_cred_passthrough() to
fix (2), (3) and (4) respectively.

The mapped and mapped-file security modes are supposed to be identical,
except for the place where credentials and file modes are stored. While
here, we also make that explicit by sharing the call to mkdirat().

This partly fixes CVE-2016-9602.

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 hw/9pfs/9p-local.c | 55 ++++++++++++++++++++----------------------------------
 1 file changed, 20 insertions(+), 35 deletions(-)

(limited to 'hw')

diff --git a/hw/9pfs/9p-local.c b/hw/9pfs/9p-local.c
index db70c2d..33893d5 100644
--- a/hw/9pfs/9p-local.c
+++ b/hw/9pfs/9p-local.c
@@ -799,62 +799,47 @@ out:
 static int local_mkdir(FsContext *fs_ctx, V9fsPath *dir_path,
                        const char *name, FsCred *credp)
 {
-    char *path;
     int err = -1;
-    int serrno = 0;
-    V9fsString fullname;
-    char *buffer = NULL;
+    int dirfd;
 
-    v9fs_string_init(&fullname);
-    v9fs_string_sprintf(&fullname, "%s/%s", dir_path->data, name);
-    path = fullname.data;
+    dirfd = local_opendir_nofollow(fs_ctx, dir_path->data);
+    if (dirfd == -1) {
+        return -1;
+    }
 
-    /* Determine the security model */
-    if (fs_ctx->export_flags & V9FS_SM_MAPPED) {
-        buffer = rpath(fs_ctx, path);
-        err = mkdir(buffer, SM_LOCAL_DIR_MODE_BITS);
+    if (fs_ctx->export_flags & V9FS_SM_MAPPED ||
+        fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) {
+        err = mkdirat(dirfd, name, SM_LOCAL_DIR_MODE_BITS);
         if (err == -1) {
             goto out;
         }
-        credp->fc_mode = credp->fc_mode|S_IFDIR;
-        err = local_set_xattr(buffer, credp);
-        if (err == -1) {
-            serrno = errno;
-            goto err_end;
-        }
-    } else if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) {
-        buffer = rpath(fs_ctx, path);
-        err = mkdir(buffer, SM_LOCAL_DIR_MODE_BITS);
-        if (err == -1) {
-            goto out;
+        credp->fc_mode = credp->fc_mode | S_IFDIR;
+
+        if (fs_ctx->export_flags & V9FS_SM_MAPPED) {
+            err = local_set_xattrat(dirfd, name, credp);
+        } else {
+            err = local_set_mapped_file_attrat(dirfd, name, credp);
         }
-        credp->fc_mode = credp->fc_mode|S_IFDIR;
-        err = local_set_mapped_file_attr(fs_ctx, path, credp);
         if (err == -1) {
-            serrno = errno;
             goto err_end;
         }
-    } else if ((fs_ctx->export_flags & V9FS_SM_PASSTHROUGH) ||
-               (fs_ctx->export_flags & V9FS_SM_NONE)) {
-        buffer = rpath(fs_ctx, path);
-        err = mkdir(buffer, credp->fc_mode);
+    } else if (fs_ctx->export_flags & V9FS_SM_PASSTHROUGH ||
+               fs_ctx->export_flags & V9FS_SM_NONE) {
+        err = mkdirat(dirfd, name, credp->fc_mode);
         if (err == -1) {
             goto out;
         }
-        err = local_post_create_passthrough(fs_ctx, path, credp);
+        err = local_set_cred_passthrough(fs_ctx, dirfd, name, credp);
         if (err == -1) {
-            serrno = errno;
             goto err_end;
         }
     }
     goto out;
 
 err_end:
-    remove(buffer);
-    errno = serrno;
+    unlinkat_preserve_errno(dirfd, name, AT_REMOVEDIR);
 out:
-    g_free(buffer);
-    v9fs_string_free(&fullname);
+    close_preserve_errno(dirfd);
     return err;
 }
 
-- 
cgit v1.1


From a565fea56546e254b7610305b07711f0a3bda0c7 Mon Sep 17 00:00:00 2001
From: Greg Kurz <groug@kaod.org>
Date: Sun, 26 Feb 2017 23:45:09 +0100
Subject: 9pfs: local: open2: don't follow symlinks

The local_open2() callback is vulnerable to symlink attacks because it
calls:

(1) open() which follows symbolic links for all path elements but the
    rightmost one
(2) local_set_xattr()->setxattr() which follows symbolic links for all
    path elements
(3) local_set_mapped_file_attr() which calls in turn local_fopen() and
    mkdir(), both functions following symbolic links for all path
    elements but the rightmost one
(4) local_post_create_passthrough() which calls in turn lchown() and
    chmod(), both functions also following symbolic links

This patch converts local_open2() to rely on opendir_nofollow() and
mkdirat() to fix (1), as well as local_set_xattrat(),
local_set_mapped_file_attrat() and local_set_cred_passthrough() to
fix (2), (3) and (4) respectively. Since local_open2() already opens
a descriptor to the target file, local_set_cred_passthrough() is
modified to reuse it instead of opening a new one.

The mapped and mapped-file security modes are supposed to be identical,
except for the place where credentials and file modes are stored. While
here, we also make that explicit by sharing the call to openat().

This partly fixes CVE-2016-9602.

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 hw/9pfs/9p-local.c | 56 ++++++++++++++++++------------------------------------
 1 file changed, 19 insertions(+), 37 deletions(-)

(limited to 'hw')

diff --git a/hw/9pfs/9p-local.c b/hw/9pfs/9p-local.c
index 33893d5..b9d4e99 100644
--- a/hw/9pfs/9p-local.c
+++ b/hw/9pfs/9p-local.c
@@ -887,62 +887,45 @@ static int local_fstat(FsContext *fs_ctx, int fid_type,
 static int local_open2(FsContext *fs_ctx, V9fsPath *dir_path, const char *name,
                        int flags, FsCred *credp, V9fsFidOpenState *fs)
 {
-    char *path;
     int fd = -1;
     int err = -1;
-    int serrno = 0;
-    V9fsString fullname;
-    char *buffer = NULL;
+    int dirfd;
 
     /*
      * Mark all the open to not follow symlinks
      */
     flags |= O_NOFOLLOW;
 
-    v9fs_string_init(&fullname);
-    v9fs_string_sprintf(&fullname, "%s/%s", dir_path->data, name);
-    path = fullname.data;
+    dirfd = local_opendir_nofollow(fs_ctx, dir_path->data);
+    if (dirfd == -1) {
+        return -1;
+    }
 
     /* Determine the security model */
-    if (fs_ctx->export_flags & V9FS_SM_MAPPED) {
-        buffer = rpath(fs_ctx, path);
-        fd = open(buffer, flags, SM_LOCAL_MODE_BITS);
+    if (fs_ctx->export_flags & V9FS_SM_MAPPED ||
+        fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) {
+        fd = openat_file(dirfd, name, flags, SM_LOCAL_MODE_BITS);
         if (fd == -1) {
-            err = fd;
             goto out;
         }
         credp->fc_mode = credp->fc_mode|S_IFREG;
-        /* Set cleint credentials in xattr */
-        err = local_set_xattr(buffer, credp);
-        if (err == -1) {
-            serrno = errno;
-            goto err_end;
-        }
-    } else if (fs_ctx->export_flags & V9FS_SM_MAPPED_FILE) {
-        buffer = rpath(fs_ctx, path);
-        fd = open(buffer, flags, SM_LOCAL_MODE_BITS);
-        if (fd == -1) {
-            err = fd;
-            goto out;
+        if (fs_ctx->export_flags & V9FS_SM_MAPPED) {
+            /* Set cleint credentials in xattr */
+            err = local_set_xattrat(dirfd, name, credp);
+        } else {
+            err = local_set_mapped_file_attrat(dirfd, name, credp);
         }
-        credp->fc_mode = credp->fc_mode|S_IFREG;
-        /* Set client credentials in .virtfs_metadata directory files */
-        err = local_set_mapped_file_attr(fs_ctx, path, credp);
         if (err == -1) {
-            serrno = errno;
             goto err_end;
         }
     } else if ((fs_ctx->export_flags & V9FS_SM_PASSTHROUGH) ||
                (fs_ctx->export_flags & V9FS_SM_NONE)) {
-        buffer = rpath(fs_ctx, path);
-        fd = open(buffer, flags, credp->fc_mode);
+        fd = openat_file(dirfd, name, flags, credp->fc_mode);
         if (fd == -1) {
-            err = fd;
             goto out;
         }
-        err = local_post_create_passthrough(fs_ctx, path, credp);
+        err = local_set_cred_passthrough(fs_ctx, dirfd, name, credp);
         if (err == -1) {
-            serrno = errno;
             goto err_end;
         }
     }
@@ -951,12 +934,11 @@ static int local_open2(FsContext *fs_ctx, V9fsPath *dir_path, const char *name,
     goto out;
 
 err_end:
-    close(fd);
-    remove(buffer);
-    errno = serrno;
+    unlinkat_preserve_errno(dirfd, name,
+                            flags & O_DIRECTORY ? AT_REMOVEDIR : 0);
+    close_preserve_errno(fd);
 out:
-    g_free(buffer);
-    v9fs_string_free(&fullname);
+    close_preserve_errno(dirfd);
     return err;
 }
 
-- 
cgit v1.1


From c23d5f1d5bc0e23aeb845b1af8f996f16783ce98 Mon Sep 17 00:00:00 2001
From: Greg Kurz <groug@kaod.org>
Date: Sun, 26 Feb 2017 23:45:17 +0100
Subject: 9pfs: local: drop unused code

Now that the all callbacks have been converted to use "at" syscalls, we
can drop this code.

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 hw/9pfs/9p-local.c | 198 -----------------------------------------------------
 1 file changed, 198 deletions(-)

(limited to 'hw')

diff --git a/hw/9pfs/9p-local.c b/hw/9pfs/9p-local.c
index b9d4e99..432a30c 100644
--- a/hw/9pfs/9p-local.c
+++ b/hw/9pfs/9p-local.c
@@ -84,48 +84,6 @@ static void unlinkat_preserve_errno(int dirfd, const char *path, int flags)
 
 #define VIRTFS_META_DIR ".virtfs_metadata"
 
-static char *local_mapped_attr_path(FsContext *ctx, const char *path)
-{
-    int dirlen;
-    const char *name = strrchr(path, '/');
-    if (name) {
-        dirlen = name - path;
-        ++name;
-    } else {
-        name = path;
-        dirlen = 0;
-    }
-    return g_strdup_printf("%s/%.*s/%s/%s", ctx->fs_root,
-                           dirlen, path, VIRTFS_META_DIR, name);
-}
-
-static FILE *local_fopen(const char *path, const char *mode)
-{
-    int fd, o_mode = 0;
-    FILE *fp;
-    int flags = O_NOFOLLOW;
-    /*
-     * only supports two modes
-     */
-    if (mode[0] == 'r') {
-        flags |= O_RDONLY;
-    } else if (mode[0] == 'w') {
-        flags |= O_WRONLY | O_TRUNC | O_CREAT;
-        o_mode = S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH;
-    } else {
-        return NULL;
-    }
-    fd = open(path, flags, o_mode);
-    if (fd == -1) {
-        return NULL;
-    }
-    fp = fdopen(fd, mode);
-    if (!fp) {
-        close(fd);
-    }
-    return fp;
-}
-
 static FILE *local_fopenat(int dirfd, const char *name, const char *mode)
 {
     int fd, o_mode = 0;
@@ -238,135 +196,6 @@ out:
     return err;
 }
 
-static int local_create_mapped_attr_dir(FsContext *ctx, const char *path)
-{
-    int err;
-    char *attr_dir;
-    char *tmp_path = g_strdup(path);
-
-    attr_dir = g_strdup_printf("%s/%s/%s",
-             ctx->fs_root, dirname(tmp_path), VIRTFS_META_DIR);
-
-    err = mkdir(attr_dir, 0700);
-    if (err < 0 && errno == EEXIST) {
-        err = 0;
-    }
-    g_free(attr_dir);
-    g_free(tmp_path);
-    return err;
-}
-
-static int local_set_mapped_file_attr(FsContext *ctx,
-                                      const char *path, FsCred *credp)
-{
-    FILE *fp;
-    int ret = 0;
-    char buf[ATTR_MAX];
-    char *attr_path;
-    int uid = -1, gid = -1, mode = -1, rdev = -1;
-
-    attr_path = local_mapped_attr_path(ctx, path);
-    fp = local_fopen(attr_path, "r");
-    if (!fp) {
-        goto create_map_file;
-    }
-    memset(buf, 0, ATTR_MAX);
-    while (fgets(buf, ATTR_MAX, fp)) {
-        if (!strncmp(buf, "virtfs.uid", 10)) {
-            uid = atoi(buf+11);
-        } else if (!strncmp(buf, "virtfs.gid", 10)) {
-            gid = atoi(buf+11);
-        } else if (!strncmp(buf, "virtfs.mode", 11)) {
-            mode = atoi(buf+12);
-        } else if (!strncmp(buf, "virtfs.rdev", 11)) {
-            rdev = atoi(buf+12);
-        }
-        memset(buf, 0, ATTR_MAX);
-    }
-    fclose(fp);
-    goto update_map_file;
-
-create_map_file:
-    ret = local_create_mapped_attr_dir(ctx, path);
-    if (ret < 0) {
-        goto err_out;
-    }
-
-update_map_file:
-    fp = local_fopen(attr_path, "w");
-    if (!fp) {
-        ret = -1;
-        goto err_out;
-    }
-
-    if (credp->fc_uid != -1) {
-        uid = credp->fc_uid;
-    }
-    if (credp->fc_gid != -1) {
-        gid = credp->fc_gid;
-    }
-    if (credp->fc_mode != -1) {
-        mode = credp->fc_mode;
-    }
-    if (credp->fc_rdev != -1) {
-        rdev = credp->fc_rdev;
-    }
-
-
-    if (uid != -1) {
-        fprintf(fp, "virtfs.uid=%d\n", uid);
-    }
-    if (gid != -1) {
-        fprintf(fp, "virtfs.gid=%d\n", gid);
-    }
-    if (mode != -1) {
-        fprintf(fp, "virtfs.mode=%d\n", mode);
-    }
-    if (rdev != -1) {
-        fprintf(fp, "virtfs.rdev=%d\n", rdev);
-    }
-    fclose(fp);
-
-err_out:
-    g_free(attr_path);
-    return ret;
-}
-
-static int local_set_xattr(const char *path, FsCred *credp)
-{
-    int err;
-
-    if (credp->fc_uid != -1) {
-        uint32_t tmp_uid = cpu_to_le32(credp->fc_uid);
-        err = setxattr(path, "user.virtfs.uid", &tmp_uid, sizeof(uid_t), 0);
-        if (err) {
-            return err;
-        }
-    }
-    if (credp->fc_gid != -1) {
-        uint32_t tmp_gid = cpu_to_le32(credp->fc_gid);
-        err = setxattr(path, "user.virtfs.gid", &tmp_gid, sizeof(gid_t), 0);
-        if (err) {
-            return err;
-        }
-    }
-    if (credp->fc_mode != -1) {
-        uint32_t tmp_mode = cpu_to_le32(credp->fc_mode);
-        err = setxattr(path, "user.virtfs.mode", &tmp_mode, sizeof(mode_t), 0);
-        if (err) {
-            return err;
-        }
-    }
-    if (credp->fc_rdev != -1) {
-        uint64_t tmp_rdev = cpu_to_le64(credp->fc_rdev);
-        err = setxattr(path, "user.virtfs.rdev", &tmp_rdev, sizeof(dev_t), 0);
-        if (err) {
-            return err;
-        }
-    }
-    return 0;
-}
-
 static int local_set_mapped_file_attrat(int dirfd, const char *name,
                                         FsCred *credp)
 {
@@ -516,33 +345,6 @@ static int local_set_xattrat(int dirfd, const char *path, FsCred *credp)
     return 0;
 }
 
-static int local_post_create_passthrough(FsContext *fs_ctx, const char *path,
-                                         FsCred *credp)
-{
-    char *buffer;
-
-    buffer = rpath(fs_ctx, path);
-    if (lchown(buffer, credp->fc_uid, credp->fc_gid) < 0) {
-        /*
-         * If we fail to change ownership and if we are
-         * using security model none. Ignore the error
-         */
-        if ((fs_ctx->export_flags & V9FS_SEC_MASK) != V9FS_SM_NONE) {
-            goto err;
-        }
-    }
-
-    if (chmod(buffer, credp->fc_mode & 07777) < 0) {
-        goto err;
-    }
-
-    g_free(buffer);
-    return 0;
-err:
-    g_free(buffer);
-    return -1;
-}
-
 static int local_set_cred_passthrough(FsContext *fs_ctx, int dirfd,
                                       const char *name, FsCred *credp)
 {
-- 
cgit v1.1