6.6-stable review patch. If anyone has any objections, please let me know.
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From: Shuhao Fu sfual@cse.ust.hk
commit ab529e6ca1f67bcf31f3ea80c72bffde2e9e053e upstream.
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 sfual@cse.ust.hk Acked-by: Paulo Alcantara (Red Hat) pc@manguebit.org Cc: stable@vger.kernel.org Signed-off-by: Steve French stfrench@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/smb/client/smb2inode.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)
--- a/fs/smb/client/smb2inode.c +++ b/fs/smb/client/smb2inode.c @@ -206,8 +206,10 @@ replay_again: 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];
@@ -828,6 +830,7 @@ finished: smb2_should_replay(tcon, &retries, &cur_sleep)) goto replay_again;
+out: if (cfile) cifsFileInfo_put(cfile);