Re: [PATCH][SMB3] remove confusing dmesg when mounting with encryption

[Steve French <smfrench@gmail.com>]

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Here is updated patch which following Pavel's suggestion simply
removes the sometimes confusing warning rather than make a more
complex change which checks for whether the packet was decrypted
earlier or not


On Tue, Nov 5, 2019 at 4:47 PM Steve French <smfrench@gmail.com> wrote:
>
> The smb2/smb3 message checking code was logging to dmesg when mounting
> with encryption ("seal") for compounded SMB3 requests.  When encrypted
> the whole frame (including potentially multiple compounds) is read
> so the length field is longer than in the case of non-encrypted
> case (where length field will match the the calculated length for
> the particular SMB3 request in the compound being validated).
>
> Avoids the warning on mount (with "seal"):
>
>    "srv rsp padded more than expected. Length 384 not ..."
>
> --
> Thanks,
>
> Steve



-- 
Thanks,

Steve

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From 0ad92ed9bf9cd9e4bc9412d3f6e9ccbfcc27fb43 Mon Sep 17 00:00:00 2001
From: Steve French <stfrench@microsoft.com>
Date: Fri, 8 Nov 2019 01:01:35 -0600
Subject: [PATCH 1/2] smb3: remove confusing dmesg when mounting with
 encryption ("seal")

The smb2/smb3 message checking code was logging to dmesg when mounting
with encryption ("seal") for compounded SMB3 requests.  When encrypted
the whole frame (including potentially multiple compounds) is read
so the length field is longer than in the case of non-encrypted
case (where length field will match the the calculated length for
the particular SMB3 request in the compound being validated).

Avoids the warning on mount (with "seal"):

   "srv rsp padded more than expected. Length 384 not ..."

Signed-off-by: Steve French <stfrench@microsoft.com>
---
 fs/cifs/smb2misc.c | 10 ++--------
 1 file changed, 2 insertions(+), 8 deletions(-)

diff --git a/fs/cifs/smb2misc.c b/fs/cifs/smb2misc.c
index 4b7ff3d1e830..a524fc1fad84 100644
--- a/fs/cifs/smb2misc.c
+++ b/fs/cifs/smb2misc.c
@@ -250,16 +250,10 @@ smb2_check_message(char *buf, unsigned int len, struct TCP_Server_Info *srvr)
 		 * of junk. Other servers match RFC1001 len to actual
 		 * SMB2/SMB3 frame length (header + smb2 response specific data)
 		 * Some windows servers also pad up to 8 bytes when compounding.
-		 * If pad is longer than eight bytes, log the server behavior
-		 * (once), since may indicate a problem but allow it and continue
-		 * since the frame is parseable.
 		 */
-		if (clc_len < len) {
-			pr_warn_once(
-			     "srv rsp padded more than expected. Length %d not %d for cmd:%d mid:%llu\n",
-			     len, clc_len, command, mid);
+		if (clc_len < len)
 			return 0;
-		}
+
 		pr_warn_once(
 			"srv rsp too short, len %d not %d. cmd:%d mid:%llu\n",
 			len, clc_len, command, mid);
-- 
2.23.0