diff options
| author | Paul Aurich <paul@darkrain42.org> | 2025-05-07 08:28:09 +0300 |
|---|---|---|
| committer | Steve French <stfrench@microsoft.com> | 2025-05-07 23:24:46 +0300 |
| commit | 3ca02e63edccb78ef3659bebc68579c7224a6ca2 (patch) | |
| tree | 91bc586c7988d6550311fe7382f6352b09ea5dd2 | |
| parent | d90b023718a17d308d831fde36b3bb6fa3b511e0 (diff) | |
| download | linux-3ca02e63edccb78ef3659bebc68579c7224a6ca2.tar.xz | |
smb: client: Avoid race in open_cached_dir with lease breaks
A pre-existing valid cfid returned from find_or_create_cached_dir might
race with a lease break, meaning open_cached_dir doesn't consider it
valid, and thinks it's newly-constructed. This leaks a dentry reference
if the allocation occurs before the queued lease break work runs.
Avoid the race by extending holding the cfid_list_lock across
find_or_create_cached_dir and when the result is checked.
Cc: stable@vger.kernel.org
Reviewed-by: Henrique Carvalho <henrique.carvalho@suse.com>
Signed-off-by: Paul Aurich <paul@darkrain42.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
| -rw-r--r-- | fs/smb/client/cached_dir.c | 10 |
1 files changed, 2 insertions, 8 deletions
diff --git a/fs/smb/client/cached_dir.c b/fs/smb/client/cached_dir.c index fe738623cf1b..240d82c6f908 100644 --- a/fs/smb/client/cached_dir.c +++ b/fs/smb/client/cached_dir.c @@ -29,7 +29,6 @@ static struct cached_fid *find_or_create_cached_dir(struct cached_fids *cfids, { struct cached_fid *cfid; - spin_lock(&cfids->cfid_list_lock); list_for_each_entry(cfid, &cfids->entries, entry) { if (!strcmp(cfid->path, path)) { /* @@ -38,25 +37,20 @@ static struct cached_fid *find_or_create_cached_dir(struct cached_fids *cfids, * being deleted due to a lease break. */ if (!cfid->time || !cfid->has_lease) { - spin_unlock(&cfids->cfid_list_lock); return NULL; } kref_get(&cfid->refcount); - spin_unlock(&cfids->cfid_list_lock); return cfid; } } if (lookup_only) { - spin_unlock(&cfids->cfid_list_lock); return NULL; } if (cfids->num_entries >= max_cached_dirs) { - spin_unlock(&cfids->cfid_list_lock); return NULL; } cfid = init_cached_dir(path); if (cfid == NULL) { - spin_unlock(&cfids->cfid_list_lock); return NULL; } cfid->cfids = cfids; @@ -74,7 +68,6 @@ static struct cached_fid *find_or_create_cached_dir(struct cached_fids *cfids, */ cfid->has_lease = true; - spin_unlock(&cfids->cfid_list_lock); return cfid; } @@ -187,8 +180,10 @@ replay_again: if (!utf16_path) return -ENOMEM; + spin_lock(&cfids->cfid_list_lock); cfid = find_or_create_cached_dir(cfids, path, lookup_only, tcon->max_cached_dirs); if (cfid == NULL) { + spin_unlock(&cfids->cfid_list_lock); kfree(utf16_path); return -ENOENT; } @@ -197,7 +192,6 @@ replay_again: * Otherwise, it is either a new entry or laundromat worker removed it * from @cfids->entries. Caller will put last reference if the latter. */ - spin_lock(&cfids->cfid_list_lock); if (cfid->has_lease && cfid->time) { spin_unlock(&cfids->cfid_list_lock); *ret_cfid = cfid; |