smb: client: fix parsing of SMB3.1.1 POSIX create context

[ Upstream commit 76025cc2285d9ede3d717fe4305d66f8be2d9346 ]

The data offset for the SMB3.1.1 POSIX create context will always be
8-byte aligned so having the check 'noff + nlen >= doff' in
smb2_parse_contexts() is wrong as it will lead to -EINVAL because noff
+ nlen == doff.

Fix the sanity check to correctly handle aligned create context data.

Fixes: af1689a9b770 ("smb: client: fix potential OOBs in smb2_parse_contexts()")
Signed-off-by: Paulo Alcantara <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/fs/smb/client/smb2pdu.c b/fs/smb/client/smb2pdu.c
index 5276992..888eb59 100644 (file)
--- a/fs/smb/client/smb2pdu.c
+++ b/fs/smb/client/smb2pdu.c
@@ -2185,7 +2185,7 @@ int smb2_parse_contexts(struct TCP_Server_Info *server,
 
                noff = le16_to_cpu(cc->NameOffset);
                nlen = le16_to_cpu(cc->NameLength);
-               if (noff + nlen >= doff)
+               if (noff + nlen > doff)
                        return -EINVAL;
 
                name = (char *)cc + noff;