From: Shuhao Fu Date: Wed, 27 Aug 2025 18:24:19 +0000 (+0800) Subject: fs/smb: Fix inconsistent refcnt update X-Git-Tag: v6.17-rc4~9^2 X-Git-Url: https://gentwo.org/gitweb/?a=commitdiff_plain;h=ab529e6ca1f67bcf31f3ea80c72bffde2e9e053e;p=linux%2F.git fs/smb: Fix inconsistent refcnt update A possible inconsistent update of refcount was identified in `smb2_compound_op`. Such inconsistent update could lead to possible resource leaks. Why it is a possible bug: 1. In the comment section of the function, it clearly states that the reference to `cfile` should be dropped after calling this function. 2. Every control flow path would check and drop the reference to `cfile`, except the patched one. 3. Existing callers would not handle refcount update of `cfile` if -ENOMEM is returned. To fix the bug, an extra goto label "out" is added, to make sure that the cleanup logic would always be respected. As the problem is caused by the allocation failure of `vars`, the cleanup logic between label "finished" and "out" can be safely ignored. According to the definition of function `is_replayable_error`, the error code of "-ENOMEM" is not recoverable. Therefore, the replay logic also gets ignored. Signed-off-by: Shuhao Fu Acked-by: Paulo Alcantara (Red Hat) Cc: stable@vger.kernel.org Signed-off-by: Steve French --- diff --git a/fs/smb/client/smb2inode.c b/fs/smb/client/smb2inode.c index 2a0316c514e4..31c13fb5b85b 100644 --- a/fs/smb/client/smb2inode.c +++ b/fs/smb/client/smb2inode.c @@ -207,8 +207,10 @@ static int smb2_compound_op(const unsigned int xid, struct cifs_tcon *tcon, server = cifs_pick_channel(ses); vars = kzalloc(sizeof(*vars), GFP_ATOMIC); - if (vars == NULL) - return -ENOMEM; + if (vars == NULL) { + rc = -ENOMEM; + goto out; + } rqst = &vars->rqst[0]; rsp_iov = &vars->rsp_iov[0]; @@ -864,6 +866,7 @@ static int smb2_compound_op(const unsigned int xid, struct cifs_tcon *tcon, smb2_should_replay(tcon, &retries, &cur_sleep)) goto replay_again; +out: if (cfile) cifsFileInfo_put(cfile);