[PATCH 5.10 006/122] smb: client: fix parsing of SMB3.1.1 POSIX create context

Greg Kroah-Hartman
2024-02-27T14:27:33Z

From: Paulo Alcantara <pc@manguebit.com>

[ 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>
[Guru:smb2_parse_contexts() is present in file smb2ops.c,
smb2ops.c file location is changed, modified patch accordingly.]
Signed-off-by: Guruswamy Basavaiah <guruswamy.basavaiah@broadcom.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
fs/cifs/smb2pdu.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -2030,7 +2030,7 @@ int smb2_parse_contexts(struct TCP_Serve

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;