From f57f5878578af19f72344439154234c6d6ba8ccc Mon Sep 17 00:00:00 2001 From: Greg Kurz Date: Thu, 25 May 2017 10:30:14 +0200 Subject: 9pfs: local: resolve special directories in paths When using the mapped-file security mode, the creds of a path /foo/bar are stored in the /foo/.virtfs_metadata/bar file. This is okay for all paths unless they end with '.' or '..', because we cannot create the corresponding file in the metadata directory. This patch ensures that '.' and '..' are resolved in all paths. The core code only passes path elements (no '/') to the backend, with the notable exception of the '/' path, which refers to the virtfs root. This patch preserves the current behavior of converting it to '.' so that it can be passed to "*at()" syscalls ('/' would mean the host root). Signed-off-by: Greg Kurz Reviewed-by: Eric Blake --- hw/9pfs/9p-local.c | 32 +++++++++++++++++++++++++------- 1 file changed, 25 insertions(+), 7 deletions(-) (limited to 'hw/9pfs') diff --git a/hw/9pfs/9p-local.c b/hw/9pfs/9p-local.c index 226234d..68e9265 100644 --- a/hw/9pfs/9p-local.c +++ b/hw/9pfs/9p-local.c @@ -1134,14 +1134,32 @@ static int local_name_to_path(FsContext *ctx, V9fsPath *dir_path, } if (dir_path) { - v9fs_path_sprintf(target, "%s/%s", dir_path->data, name); - } else if (strcmp(name, "/")) { - v9fs_path_sprintf(target, "%s", name); + if (!strcmp(name, ".")) { + /* "." relative to "foo/bar" is "foo/bar" */ + v9fs_path_copy(target, dir_path); + } else if (!strcmp(name, "..")) { + if (!strcmp(dir_path->data, ".")) { + /* ".." relative to the root is "." */ + v9fs_path_sprintf(target, "."); + } else { + char *tmp = g_path_get_dirname(dir_path->data); + /* Symbolic links are resolved by the client. We can assume + * that ".." relative to "foo/bar" is equivalent to "foo" + */ + v9fs_path_sprintf(target, "%s", tmp); + g_free(tmp); + } + } else { + assert(!strchr(name, '/')); + v9fs_path_sprintf(target, "%s/%s", dir_path->data, name); + } + } else if (!strcmp(name, "/") || !strcmp(name, ".") || + !strcmp(name, "..")) { + /* This is the root fid */ + v9fs_path_sprintf(target, "."); } else { - /* We want the path of the export root to be relative, otherwise - * "*at()" syscalls would treat it as "/" in the host. - */ - v9fs_path_sprintf(target, "%s", "."); + assert(!strchr(name, '/')); + v9fs_path_sprintf(target, "./%s", name); } return 0; } -- cgit v1.1