[PATCH 5.15.y 3/3] smb: client: close handle after create-context parsing failure

[Sasha Levin <sashal@kernel.org>]

From: Zihan Xi <zihanx@nebusec.ai>

[ Upstream commit 566820af017e81497fb5e9d3ad6e7ffe2828bc8b ]

SMB2_open() accounts a successful CREATE response as a remote open before
parsing its create contexts.  If smb2_parse_contexts() rejects malformed
context data, SMB2_open() returns without closing the handle, leaving the
server-side handle open and num_remote_opens elevated.

Close the handle after a post-CREATE context parsing failure so the error
path releases the remote resource and balances the open count.

Fixes: af1689a9b770 ("smb: client: fix potential OOBs in smb2_parse_contexts()")
Cc: stable@vger.kernel.org
Reported-by: Vega <vega@nebusec.ai>
Assisted-by: LLM
Co-developed-by: Luxing Yin <root@tr0jan.top>
Signed-off-by: Luxing Yin <root@tr0jan.top>
Signed-off-by: Zihan Xi <zihanx@nebusec.ai>
Tested-by: Frank Sorenson <sorenson@redhat.com>
Signed-off-by: Paulo Alcantara <pc@manguebit.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/cifs/smb2pdu.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
index 8c46757d4c838..c154803d6646e 100644
--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -3007,6 +3007,9 @@ SMB2_open(const unsigned int xid, struct cifs_open_parms *oparms, __le16 *path,
 
 	rc = smb2_parse_contexts(server, &rsp_iov, &oparms->fid->epoch,
 				 oparms->fid->lease_key, oplock, file_info, posix);
+	if (rc)
+		SMB2_close(xid, tcon, oparms->fid->persistent_fid,
+			   oparms->fid->volatile_fid);
 
 	trace_smb3_open_done(xid, rsp->PersistentFileId, tcon->tid, ses->Suid,
 			     oparms->create_options, oparms->desired_access);
-- 
2.53.0