ksmbd: smb2: Allow messages padded to 8byte boundary

commit e7b8b8ed9960bf699bf4029f482d9e869c094ed6 upstream.

clc length is now accepted to <= 8 less than length,
rather than < 8.

Solve issues on some of Axis's smb clients which send
messages where clc length is 8 bytes less than length.

The specific client was running kernel 4.19.217 with
smb dialect 3.0.2 on armv7l.

Cc: stable@vger.kernel.org
Signed-off-by: Gustav Johansson <gustajo@axis.com>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/ksmbd/smb2misc.c b/fs/ksmbd/smb2misc.c
index fbdde426dd01dfe35725bfc40be9ca8e6f81de29..0ffe663b75906a9556d7e4ef55ed754c38fc27ae 100644 (file)
--- a/fs/ksmbd/smb2misc.c
+++ b/fs/ksmbd/smb2misc.c
@@ -416,8 +416,11 @@ int ksmbd_smb2_check_message(struct ksmbd_work *work)
 
                /*
                 * Allow a message that padded to 8byte boundary.
+                * Linux 4.19.217 with smb 3.0.2 are sometimes
+                * sending messages where the cls_len is exactly
+                * 8 bytes less than len.
                 */
-               if (clc_len < len && (len - clc_len) < 8)
+               if (clc_len < len && (len - clc_len) <= 8)
                        goto validate_credit;
 
                pr_err_ratelimited(