smb3: minor debugging clarifications in rfc1001 len processing (25f25735) · Commits · 戴 / test

I ran into some cases where server was returning the wrong length on frames but I couldn't easily match them to the command in the network trace (or server logs) since I need the command and/or multiplex id to find the offending SMB2/SMB3 command. Add these two fields to the log message. In the case of padding too much it may not be a problem in all cases but might have correlated to a network disconnect case in some problems we have been looking at. In the case of frame too short is even more important. Signed-off-by:

Steve French <stfrench@microsoft.com> Reviewed-by:

Ronnie Sahlberg <lsahlber@redhat.com>

fs/cifs/smb2misc.c

+9 −5

Original line number	Diff line number	Diff line
		@@ -248,16 +248,20 @@ smb2_check_message(char buf, unsigned int len, struct TCP_Server_Info srvr)
		* MacOS server pads after SMB2.1 write response with 3 bytes
		* of junk. Other servers match RFC1001 len to actual
		* SMB2/SMB3 frame length (header + smb2 response specific data)
		* Some windows servers do too when compounding is used.
		* Log the server error (once), but allow it and continue
		* 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) {
		printk_once(KERN_WARNING
		"SMB2 server sent bad RFC1001 len %d not %d\n",
		len, clc_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);
		return 0;
		}
		pr_warn_once(
		"srv rsp too short, len %d not %d. cmd:%d mid:%llu\n",
		len, clc_len, command, mid);

		return 1;
		}

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