diff options
| author | Nirmoy Das <nirmoyd@nvidia.com> | 2026-05-14 07:42:57 -0700 |
|---|---|---|
| committer | Christian Brauner <brauner@kernel.org> | 2026-05-18 14:56:15 +0200 |
| commit | 1711b6ed6953cee5940ca4c3a6e77f1b3798cee2 (patch) | |
| tree | 934680b1890d5648d32f66ac04a3afbde4d1f050 /fs/overlayfs | |
| parent | 8a220d1c312c66194f4a33dd52d1fba42bc2b341 (diff) | |
ovl: keep err zero after successful ovl_cache_get()
ovl_iterate_merged() stores PTR_ERR(cache) in err before checking
IS_ERR(cache). On success err holds the truncated cache pointer and
can be returned as a bogus non-zero error.
The syzbot reproducer reaches this through overlay-on-overlay readdir:
getdents64
iterate_dir(outer overlay file)
ovl_iterate_merged()
ovl_cache_get()
ovl_dir_read_merged()
ovl_dir_read()
iterate_dir(inner overlay file)
ovl_iterate_merged()
Only compute PTR_ERR(cache) on the error path.
Fixes: d25e4b739f83 ("ovl: refactor ovl_iterate() and port to cred guard")
Reported-by: syzbot+a16fb0cce329a320661c@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=a16fb0cce329a320661c
Cc: stable@vger.kernel.org
Signed-off-by: Nirmoy Das <nirmoyd@nvidia.com>
Link: https://patch.msgid.link/20260514144258.3068715-1-nirmoyd@nvidia.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
Diffstat (limited to 'fs/overlayfs')
| -rw-r--r-- | fs/overlayfs/readdir.c | 7 |
1 files changed, 3 insertions, 4 deletions
diff --git a/fs/overlayfs/readdir.c b/fs/overlayfs/readdir.c index 1dcc75b3a90f..e7fe29cb6028 100644 --- a/fs/overlayfs/readdir.c +++ b/fs/overlayfs/readdir.c @@ -838,15 +838,14 @@ static int ovl_iterate_merged(struct file *file, struct dir_context *ctx) struct ovl_dir_file *od = file->private_data; struct dentry *dentry = file->f_path.dentry; struct ovl_cache_entry *p; - int err = 0; + int err; if (!od->cache) { struct ovl_dir_cache *cache; cache = ovl_cache_get(dentry); - err = PTR_ERR(cache); if (IS_ERR(cache)) - return err; + return PTR_ERR(cache); od->cache = cache; ovl_seek_cursor(od, ctx->pos); @@ -869,7 +868,7 @@ static int ovl_iterate_merged(struct file *file, struct dir_context *ctx) od->cursor = p->l_node.next; ctx->pos++; } - return err; + return 0; } static bool ovl_need_adjust_d_ino(struct file *file) |