diff options
| -rw-r--r-- | NEWS | 5 | ||||
| -rw-r--r-- | htl/Makefile | 2 | ||||
| -rw-r--r-- | htl/Versions | 1 | ||||
| -rw-r--r-- | include/shm-directory.h (renamed from sysdeps/nptl/shm-directory.h) | 30 | ||||
| -rw-r--r-- | nptl/Makefile | 1 | ||||
| -rw-r--r-- | nptl/Versions | 1 | ||||
| -rw-r--r-- | nptl/nptlfreeres.c | 1 | ||||
| -rw-r--r-- | nptl/pthreadP.h | 1 | ||||
| -rw-r--r-- | posix/Makefile | 3 | ||||
| -rw-r--r-- | posix/Versions | 1 | ||||
| -rw-r--r-- | posix/shm-directory.c (renamed from sysdeps/posix/shm-directory.c) | 30 | ||||
| -rw-r--r-- | sysdeps/htl/shm-directory.h | 30 | ||||
| -rw-r--r-- | sysdeps/posix/Makefile | 6 | ||||
| -rw-r--r-- | sysdeps/posix/shm-directory.h | 66 | ||||
| -rw-r--r-- | sysdeps/posix/shm_open.c | 10 | ||||
| -rw-r--r-- | sysdeps/posix/shm_unlink.c | 13 | ||||
| -rw-r--r-- | sysdeps/pthread/sem_open.c | 34 | ||||
| -rw-r--r-- | sysdeps/pthread/sem_unlink.c | 10 | ||||
| -rw-r--r-- | sysdeps/unix/sysv/linux/shm-directory.c | 147 |
19 files changed, 89 insertions, 303 deletions
@@ -20,7 +20,10 @@ Deprecated and removed features, and other changes affecting compatibility: Changes to build and runtime requirements: - [Add changes to build and runtime requirements here] +* On Linux, the shm_open, sem_open, and related functions now expect the + file shared memory file system to be mounted at /dev/shm. These functions + no longer search among the system's mount points for a suitable + replacement if /dev/shm is not available. Security related changes: diff --git a/htl/Makefile b/htl/Makefile index 38d9f8c..9adc95e 100644 --- a/htl/Makefile +++ b/htl/Makefile @@ -132,8 +132,6 @@ libpthread-routines := pt-attr pt-attr-destroy pt-attr-getdetachstate \ sem-post sem-timedwait sem-trywait sem_unlink \ sem-wait sem-waitfast \ \ - shm-directory \ - \ cancellation \ cthreads-compat \ herrno \ diff --git a/htl/Versions b/htl/Versions index 9549629..9506043 100644 --- a/htl/Versions +++ b/htl/Versions @@ -168,7 +168,6 @@ libpthread { GLIBC_PRIVATE { __pthread_initialize_minimal; - __shm_directory; __pthread_threads; __cthread_detach; diff --git a/sysdeps/nptl/shm-directory.h b/include/shm-directory.h index 995f598..1d3ffb6 100644 --- a/sysdeps/nptl/shm-directory.h +++ b/include/shm-directory.h @@ -1,4 +1,4 @@ -/* Header for directory for shm/sem files. NPTL version. +/* Header for directory for shm/sem files. Copyright (C) 2014-2021 Free Software Foundation, Inc. This file is part of the GNU C Library. @@ -18,14 +18,24 @@ #ifndef _SHM_DIRECTORY_H -#include <sysdeps/posix/shm-directory.h> - -/* For NPTL the __shm_directory function lives in libpthread. - We don't want PLT calls from there. But it's also used from - librt, so it cannot just be declared hidden. */ - -#if IS_IN (libpthread) -hidden_proto (__shm_directory) -#endif +#include <limits.h> +#include <paths.h> +#include <stdbool.h> + +/* The directory that contains shared POSIX objects. */ +#define SHMDIR _PATH_DEV "shm/" + +struct shmdir_name +{ + /* The combined prefix/name. The sizeof includes the terminating + NUL byte. 4 bytes are needed for the optional "sem." prefix. */ + char name[sizeof (SHMDIR) + 4 + NAME_MAX]; +}; + +/* Sets RESULT->name to the constructed name and returns 0 on success, + or -1 on failure. Includes the "sem." prefix in the name if + SEM_PREFIX is true. */ +int __shm_get_name (struct shmdir_name *result, const char *name, + bool sem_prefix); #endif /* shm-directory.h */ diff --git a/nptl/Makefile b/nptl/Makefile index 0282e07..c49134b 100644 --- a/nptl/Makefile +++ b/nptl/Makefile @@ -137,7 +137,6 @@ libpthread-routines = nptl-init nptlfreeres vars events version pt-interp \ pthread_once \ old_pthread_atfork \ pthread_getcpuclockid \ - shm-directory \ sem_init sem_destroy \ sem_open sem_close sem_unlink \ sem_getvalue \ diff --git a/nptl/Versions b/nptl/Versions index 02650fe..5db713d 100644 --- a/nptl/Versions +++ b/nptl/Versions @@ -303,7 +303,6 @@ libpthread { __pthread_unwind; __pthread_get_minstack; __pthread_barrier_init; __pthread_barrier_wait; __futex_abstimed_wait64; __futex_abstimed_wait_cancelable64; - __shm_directory; __libpthread_freeres; } } diff --git a/nptl/nptlfreeres.c b/nptl/nptlfreeres.c index 77ad5b5..d295bcb 100644 --- a/nptl/nptlfreeres.c +++ b/nptl/nptlfreeres.c @@ -27,6 +27,5 @@ __libpthread_freeres (void) { call_function_static_weak (__default_pthread_attr_freeres); call_function_static_weak (__nptl_stacks_freeres); - call_function_static_weak (__shm_directory_freeres); call_function_static_weak (__nptl_unwind_freeres); } diff --git a/nptl/pthreadP.h b/nptl/pthreadP.h index e5efa2e..d078128 100644 --- a/nptl/pthreadP.h +++ b/nptl/pthreadP.h @@ -629,7 +629,6 @@ extern void __nptl_set_robust (struct pthread *self); #endif extern void __nptl_stacks_freeres (void) attribute_hidden; -extern void __shm_directory_freeres (void) attribute_hidden; extern void __wait_lookup_done (void) attribute_hidden; diff --git a/posix/Makefile b/posix/Makefile index 956ef7d..f54015b 100644 --- a/posix/Makefile +++ b/posix/Makefile @@ -65,7 +65,8 @@ routines := \ spawnattr_setsigmask spawnattr_setschedpolicy spawnattr_setschedparam \ posix_madvise \ get_child_max sched_cpucount sched_cpualloc sched_cpufree \ - streams-compat + streams-compat \ + shm-directory aux := init-posix environ tests := test-errno tstgetopt testfnm runtests runptests \ diff --git a/posix/Versions b/posix/Versions index 7d06a6d..cfd3819 100644 --- a/posix/Versions +++ b/posix/Versions @@ -150,5 +150,6 @@ libc { GLIBC_PRIVATE { __libc_fork; __libc_pread; __libc_pwrite; __nanosleep_nocancel; __pause_nocancel; + __shm_get_name; } } diff --git a/sysdeps/posix/shm-directory.c b/posix/shm-directory.c index a0510c1..c06bf96 100644 --- a/sysdeps/posix/shm-directory.c +++ b/posix/shm-directory.c @@ -16,23 +16,31 @@ License along with the GNU C Library; if not, see <https://www.gnu.org/licenses/>. */ -#include <shm-directory.h> #include <unistd.h> #if _POSIX_MAPPED_FILES -# include <paths.h> - -# define SHMDIR (_PATH_DEV "shm/") +#include <alloc_buffer.h> +#include <shm-directory.h> +#include <string.h> -const char * -__shm_directory (size_t *len) +int +__shm_get_name (struct shmdir_name *result, const char *name, bool sem_prefix) { - *len = sizeof SHMDIR - 1; - return SHMDIR; + while (name[0] == '/') + ++name; + size_t namelen = strlen (name); + + struct alloc_buffer buffer + = alloc_buffer_create (result->name, sizeof (result->name)); + alloc_buffer_copy_bytes (&buffer, SHMDIR, strlen (SHMDIR)); + if (sem_prefix) + alloc_buffer_copy_bytes (&buffer, "sem.", strlen ("sem.")); + alloc_buffer_copy_bytes (&buffer, name, namelen + 1); + if (namelen == 0 || memchr (name, '/', namelen) != NULL + || alloc_buffer_has_failed (&buffer)) + return -1; + return 0; } -# if IS_IN (libpthread) -hidden_def (__shm_directory) -# endif #endif diff --git a/sysdeps/htl/shm-directory.h b/sysdeps/htl/shm-directory.h deleted file mode 100644 index 8bfd728..0000000 --- a/sysdeps/htl/shm-directory.h +++ /dev/null @@ -1,30 +0,0 @@ -/* Header for directory for shm/sem files. libpthread version. - Copyright (C) 2014-2021 Free Software Foundation, Inc. - This file is part of the GNU C Library. - - The GNU C Library is free software; you can redistribute it and/or - modify it under the terms of the GNU Lesser General Public - License as published by the Free Software Foundation; either - version 2.1 of the License, or (at your option) any later version. - - The GNU C Library is distributed in the hope that it will be useful, - but WITHOUT ANY WARRANTY; without even the implied warranty of - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - Lesser General Public License for more details. - - You should have received a copy of the GNU Lesser General Public - License along with the GNU C Library; if not, see - <https://www.gnu.org/licenses/>. */ - -#ifndef _SHM_DIRECTORY_H - -#include <sysdeps/posix/shm-directory.h> - -/* For libpthread the __shm_directory function lives in libpthread. - We don't want PLT calls from there. But it's also used from - librt, so it cannot just be declared hidden. */ - -#if IS_IN (libpthread) -hidden_proto (__shm_directory) -#endif -#endif /* shm-directory.h */ diff --git a/sysdeps/posix/Makefile b/sysdeps/posix/Makefile index 52f20f5..b58aa6a 100644 --- a/sysdeps/posix/Makefile +++ b/sysdeps/posix/Makefile @@ -3,9 +3,3 @@ L_tmpnam = 20 TMP_MAX = 238328 L_ctermid = 9 L_cuserid = 9 - -ifeq ($(subdir)|$(have-thread-library),rt|no) -# With NPTL, this lives in libpthread so it can be used for sem_open too. -# Without NPTL, it's just private in librt. -librt-routines += shm-directory -endif diff --git a/sysdeps/posix/shm-directory.h b/sysdeps/posix/shm-directory.h deleted file mode 100644 index 7254bda..0000000 --- a/sysdeps/posix/shm-directory.h +++ /dev/null @@ -1,66 +0,0 @@ -/* Header for directory for shm/sem files. - Copyright (C) 2014-2021 Free Software Foundation, Inc. - This file is part of the GNU C Library. - - The GNU C Library is free software; you can redistribute it and/or - modify it under the terms of the GNU Lesser General Public - License as published by the Free Software Foundation; either - version 2.1 of the License, or (at your option) any later version. - - The GNU C Library is distributed in the hope that it will be useful, - but WITHOUT ANY WARRANTY; without even the implied warranty of - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - Lesser General Public License for more details. - - You should have received a copy of the GNU Lesser General Public - License along with the GNU C Library; if not, see - <https://www.gnu.org/licenses/>. */ - -#ifndef _SHM_DIRECTORY_H - -#include <errno.h> -#include <limits.h> -#include <stdbool.h> -#include <stdlib.h> -#include <string.h> - -extern const char *__shm_directory (size_t *len); - -/* This defines local variables SHM_DIR and SHM_DIRLEN, giving the - directory prefix (with trailing slash) and length (not including '\0' - terminator) of the directory used for shm files. If that cannot be - determined, it sets errno to ENOSYS and returns RETVAL_FOR_INVALID. - - This uses the local variable NAME as an lvalue, and increments it past - any leading slashes. It then defines the local variable NAMELEN, giving - strlen (NAME) + 1. If NAME is invalid, it sets errno to - ERRNO_FOR_INVALID and returns RETVAL_FOR_INVALID. Finally, it defines - the local variable SHM_NAME, giving the absolute file name of the shm - file corresponding to NAME. PREFIX is a string constant used as a - prefix on NAME. */ - -#define SHM_GET_NAME(errno_for_invalid, retval_for_invalid, prefix) \ - size_t shm_dirlen; \ - const char *shm_dir = __shm_directory (&shm_dirlen); \ - /* If we don't know what directory to use, there is nothing we can do. */ \ - if (__glibc_unlikely (shm_dir == NULL)) \ - { \ - __set_errno (ENOSYS); \ - return retval_for_invalid; \ - } \ - /* Construct the filename. */ \ - while (name[0] == '/') \ - ++name; \ - size_t namelen = strlen (name) + 1; \ - /* Validate the filename. */ \ - if (namelen == 1 || namelen >= NAME_MAX || strchr (name, '/') != NULL) \ - { \ - __set_errno (errno_for_invalid); \ - return retval_for_invalid; \ - } \ - char *shm_name = __alloca (shm_dirlen + sizeof prefix - 1 + namelen); \ - __mempcpy (__mempcpy (__mempcpy (shm_name, shm_dir, shm_dirlen), \ - prefix, sizeof prefix - 1), \ - name, namelen) - -#endif /* shm-directory.h */ diff --git a/sysdeps/posix/shm_open.c b/sysdeps/posix/shm_open.c index aabc724..1817c52 100644 --- a/sysdeps/posix/shm_open.c +++ b/sysdeps/posix/shm_open.c @@ -24,6 +24,7 @@ #else +# include <errno.h> # include <fcntl.h> # include <pthread.h> # include <shm-directory.h> @@ -33,7 +34,12 @@ int shm_open (const char *name, int oflag, mode_t mode) { - SHM_GET_NAME (EINVAL, -1, ""); + struct shmdir_name dirname; + if (__shm_get_name (&dirname, name, false) != 0) + { + __set_errno (EINVAL); + return -1; + } oflag |= O_NOFOLLOW | O_CLOEXEC; @@ -41,7 +47,7 @@ shm_open (const char *name, int oflag, mode_t mode) int state; pthread_setcancelstate (PTHREAD_CANCEL_DISABLE, &state); - int fd = open (shm_name, oflag, mode); + int fd = open (dirname.name, oflag, mode); if (fd == -1 && __glibc_unlikely (errno == EISDIR)) /* It might be better to fold this error with EINVAL since directory names are just another example for unsuitable shared diff --git a/sysdeps/posix/shm_unlink.c b/sysdeps/posix/shm_unlink.c index f3258a0..c90b854 100644 --- a/sysdeps/posix/shm_unlink.c +++ b/sysdeps/posix/shm_unlink.c @@ -25,16 +25,21 @@ #include <errno.h> #include <string.h> -#include "shm-directory.h" +#include <shm-directory.h> /* Remove shared memory object. */ int shm_unlink (const char *name) { - SHM_GET_NAME (ENOENT, -1, ""); - - int result = unlink (shm_name); + struct shmdir_name dirname; + if (__shm_get_name (&dirname, name, false) != 0) + { + __set_errno (ENOENT); + return -1; + } + + int result = unlink (dirname.name); if (result < 0 && errno == EPERM) __set_errno (EACCES); return result; diff --git a/sysdeps/pthread/sem_open.c b/sysdeps/pthread/sem_open.c index b0b7221..d666414 100644 --- a/sysdeps/pthread/sem_open.c +++ b/sysdeps/pthread/sem_open.c @@ -62,8 +62,9 @@ int __sem_mappings_lock attribute_hidden = LLL_LOCK_INITIALIZER; /* Search for existing mapping and if possible add the one provided. */ static sem_t * -check_add_mapping (const char *name, size_t namelen, int fd, sem_t *existing) +check_add_mapping (const char *name, int fd, sem_t *existing) { + size_t namelen = strlen (name); sem_t *result = SEM_FAILED; /* Get the information about the file. */ @@ -150,8 +151,12 @@ sem_open (const char *name, int oflag, ...) return SEM_FAILED; } - /* Create the name of the final file in local variable SHM_NAME. */ - SHM_GET_NAME (EINVAL, SEM_FAILED, SEM_SHM_PREFIX); + struct shmdir_name dirname; + if (__shm_get_name (&dirname, name, true) != 0) + { + __set_errno (EINVAL); + return SEM_FAILED; + } /* Disable asynchronous cancellation. */ #ifdef __libc_ptf_call @@ -164,7 +169,7 @@ sem_open (const char *name, int oflag, ...) if ((oflag & O_CREAT) == 0 || (oflag & O_EXCL) == 0) { try_again: - fd = __libc_open (shm_name, + fd = __libc_open (dirname.name, (oflag & ~(O_CREAT|O_ACCMODE)) | O_NOFOLLOW | O_RDWR); if (fd == -1) @@ -178,13 +183,12 @@ sem_open (const char *name, int oflag, ...) else /* Check whether we already have this semaphore mapped and create one if necessary. */ - result = check_add_mapping (name, namelen, fd, SEM_FAILED); + result = check_add_mapping (name, fd, SEM_FAILED); } else { /* We have to open a temporary file first since it must have the correct form before we can start using it. */ - char *tmpfname; mode_t mode; unsigned int value; va_list ap; @@ -217,16 +221,11 @@ sem_open (const char *name, int oflag, ...) memset ((char *) &sem.initsem + sizeof (struct new_sem), '\0', sizeof (sem_t) - sizeof (struct new_sem)); - tmpfname = __alloca (shm_dirlen + sizeof SEM_SHM_PREFIX + 6); - char *xxxxxx = __mempcpy (tmpfname, shm_dir, shm_dirlen); - + char tmpfname[] = SHMDIR "sem.XXXXXX"; int retries = 0; #define NRETRIES 50 while (1) { - /* Add the suffix for mktemp. */ - strcpy (xxxxxx, "XXXXXX"); - /* We really want to use mktemp here. We cannot use mkstemp since the file must be opened with a specific mode. The mode cannot later be set since then we cannot apply the @@ -244,7 +243,12 @@ sem_open (const char *name, int oflag, ...) if (errno == EEXIST) { if (++retries < NRETRIES) - continue; + { + /* Restore the six placeholder bytes before the + null terminator before the next attempt. */ + memcpy (tmpfname + sizeof (tmpfname) - 7, "XXXXXX", 6); + continue; + } __set_errno (EAGAIN); } @@ -265,7 +269,7 @@ sem_open (const char *name, int oflag, ...) fd, 0)) != MAP_FAILED) { /* Create the file. Don't overwrite an existing file. */ - if (link (tmpfname, shm_name) != 0) + if (link (tmpfname, dirname.name) != 0) { /* Undo the mapping. */ (void) munmap (result, sizeof (sem_t)); @@ -290,7 +294,7 @@ sem_open (const char *name, int oflag, ...) /* Insert the mapping into the search tree. This also determines whether another thread sneaked by and already added such a mapping despite the fact that we created it. */ - result = check_add_mapping (name, namelen, fd, result); + result = check_add_mapping (name, fd, result); } /* Now remove the temporary name. This should never fail. If diff --git a/sysdeps/pthread/sem_unlink.c b/sysdeps/pthread/sem_unlink.c index faafbe4..1f06a55 100644 --- a/sysdeps/pthread/sem_unlink.c +++ b/sysdeps/pthread/sem_unlink.c @@ -27,11 +27,15 @@ int sem_unlink (const char *name) { - /* Construct the filename. */ - SHM_GET_NAME (ENOENT, -1, SEM_SHM_PREFIX); + struct shmdir_name dirname; + if (__shm_get_name (&dirname, name, true) != 0) + { + __set_errno (ENOENT); + return -1; + } /* Now try removing it. */ - int ret = unlink (shm_name); + int ret = unlink (dirname.name); if (ret < 0 && errno == EPERM) __set_errno (EACCES); return ret; diff --git a/sysdeps/unix/sysv/linux/shm-directory.c b/sysdeps/unix/sysv/linux/shm-directory.c deleted file mode 100644 index ea6d2a4..0000000 --- a/sysdeps/unix/sysv/linux/shm-directory.c +++ /dev/null @@ -1,147 +0,0 @@ -/* Determine directory for shm/sem files. Linux version. - Copyright (C) 2000-2021 Free Software Foundation, Inc. - This file is part of the GNU C Library. - - The GNU C Library is free software; you can redistribute it and/or - modify it under the terms of the GNU Lesser General Public - License as published by the Free Software Foundation; either - version 2.1 of the License, or (at your option) any later version. - - The GNU C Library is distributed in the hope that it will be useful, - but WITHOUT ANY WARRANTY; without even the implied warranty of - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - Lesser General Public License for more details. - - You should have received a copy of the GNU Lesser General Public - License along with the GNU C Library; if not, see - <https://www.gnu.org/licenses/>. */ - -#include "shm-directory.h" - -#include <errno.h> -#include <mntent.h> -#include <paths.h> -#include <stdio.h> -#include <string.h> -#include <sys/statfs.h> -#include <libc-lock.h> -#include "linux_fsinfo.h" - - -/* Mount point of the shared memory filesystem. */ -static struct -{ - char *dir; - size_t dirlen; -} mountpoint; - -/* This is the default directory. */ -static const char defaultdir[] = "/dev/shm/"; - -/* Protect the `mountpoint' variable above. */ -__libc_once_define (static, once); - - -/* Determine where the shmfs is mounted (if at all). */ -static void -where_is_shmfs (void) -{ - char buf[512]; - struct statfs f; - struct mntent resmem; - struct mntent *mp; - FILE *fp; - - /* The canonical place is /dev/shm. This is at least what the - documentation tells everybody to do. */ - if (__statfs (defaultdir, &f) == 0 && (f.f_type == SHMFS_SUPER_MAGIC - || f.f_type == RAMFS_MAGIC)) - { - /* It is in the normal place. */ - mountpoint.dir = (char *) defaultdir; - mountpoint.dirlen = sizeof (defaultdir) - 1; - - return; - } - - /* OK, do it the hard way. Look through the /proc/mounts file and if - this does not exist through /etc/fstab to find the mount point. */ - fp = __setmntent ("/proc/mounts", "r"); - if (__glibc_unlikely (fp == NULL)) - { - fp = __setmntent (_PATH_MNTTAB, "r"); - if (__glibc_unlikely (fp == NULL)) - /* There is nothing we can do. Blind guesses are not helpful. */ - return; - } - - /* Now read the entries. */ - while ((mp = __getmntent_r (fp, &resmem, buf, sizeof buf)) != NULL) - /* The original name is "shm" but this got changed in early Linux - 2.4.x to "tmpfs". */ - if (strcmp (mp->mnt_type, "tmpfs") == 0 - || strcmp (mp->mnt_type, "shm") == 0) - { - /* Found it. There might be more than one place where the - filesystem is mounted but one is enough for us. */ - size_t namelen; - - /* First make sure this really is the correct entry. At least - some versions of the kernel give wrong information because - of the implicit mount of the shmfs for SysV IPC. */ - if (__statfs (mp->mnt_dir, &f) != 0 || (f.f_type != SHMFS_SUPER_MAGIC - && f.f_type != RAMFS_MAGIC)) - continue; - - namelen = strlen (mp->mnt_dir); - - if (namelen == 0) - /* Hum, maybe some crippled entry. Keep on searching. */ - continue; - - mountpoint.dir = (char *) malloc (namelen + 2); - if (mountpoint.dir != NULL) - { - char *cp = __mempcpy (mountpoint.dir, mp->mnt_dir, namelen); - if (cp[-1] != '/') - *cp++ = '/'; - *cp = '\0'; - mountpoint.dirlen = cp - mountpoint.dir; - } - - break; - } - - /* Close the stream. */ - __endmntent (fp); -} - - -const char * -__shm_directory (size_t *len) -{ - /* Determine where the shmfs is mounted. */ - __libc_once (once, where_is_shmfs); - - /* If we don't know the mount points there is nothing we can do. Ever. */ - if (__glibc_unlikely (mountpoint.dir == NULL)) - { - __set_errno (ENOSYS); - return NULL; - } - - *len = mountpoint.dirlen; - return mountpoint.dir; -} -#if IS_IN (libpthread) -hidden_def (__shm_directory) - -/* Make sure the table is freed if we want to free everything before - exiting. */ -void -__shm_directory_freeres (void) -{ - if (mountpoint.dir != defaultdir) - free (mountpoint.dir); -} -#endif |