From: Jiri Denemark <jdenemar@redhat.com> Switch virFileIsSharedFSOverride to use virFileCheckParents to avoid a race which could result in virFileCanonicalizePath to be called on a path that does not exist anymore. Signed-off-by: Jiri Denemark <jdenemar@redhat.com> --- src/util/virfile.c | 59 +++++++++++++++++----------------------------- 1 file changed, 22 insertions(+), 37 deletions(-) diff --git a/src/util/virfile.c b/src/util/virfile.c index b0f4041df4..ea68215655 100644 --- a/src/util/virfile.c +++ b/src/util/virfile.c @@ -3502,33 +3502,6 @@ virFileCheckParents(const char *path, } -static char * -virFileGetExistingParent(const char *path) -{ - g_autofree char *dirpath = g_strdup(path); - char *p = NULL; - - /* Try less and less of the path until we get to a directory we can access. - * Even if we don't have 'x' permission on any directory in the path on the - * NFS server (assuming it's NFS), we will be able to stat the mount point. - */ - while (!virFileExists(dirpath) && p != dirpath) { - if (!(p = strrchr(dirpath, '/'))) { - virReportSystemError(EINVAL, - _("Invalid relative path '%1$s'"), path); - return NULL; - } - - if (p == dirpath) - *(p + 1) = '\0'; - else - *p = '\0'; - } - - return g_steal_pointer(&dirpath); -} - - #ifdef __linux__ # ifndef NFS_SUPER_MAGIC @@ -3875,6 +3848,17 @@ virFileGetDefaultHugepage(virHugeTLBFS *fs, } +static bool +virFileCheckParentsCanonicalize(const char *path, + void *opaque) +{ + char **canonical = opaque; + + *canonical = virFileCanonicalizePath(path); + return !!*canonical; +} + + /** * virFileIsSharedFSOverride: * @path: Path to check @@ -3888,24 +3872,25 @@ virFileIsSharedFSOverride(const char *path, char *const *overrides) { g_autofree char *dirpath = NULL; - g_autofree char *existing = NULL; char *p = NULL; + int rc; if (!path || path[0] != '/' || !overrides) return false; /* We only care about the longest existing sub-path. Further components - * may will later be created by libvirt will not magically become a shared - * filesystem. */ - if (!(existing = virFileGetExistingParent(path))) + * that may later be created by libvirt will not magically become a shared + * filesystem. Overrides have been canonicalized ahead of time, so we need + * to do the same for the provided path or we'll never be able to find a + * match if symlinks are involved. + */ + rc = virFileCheckParents(path, NULL, + virFileCheckParentsCanonicalize, &dirpath); + if (rc == -1) return false; - /* Overrides have been canonicalized ahead of time, so we need to - * do the same for the provided path or we'll never be able to - * find a match if symlinks are involved */ - if (!(dirpath = virFileCanonicalizePath(existing))) { - VIR_DEBUG("Cannot canonicalize parent '%s' of path '%s'", - existing, path); + if (rc != 0) { + VIR_DEBUG("Cannot canonicalize path '%s'", path); return false; } -- 2.52.0