mac_len uninitialized in ipt_ULOG.c

["Anders K. Pedersen"@harrier.cohaesio.com, mailnews+linux-netfilter-devel@news.cohaesio.com]

[-- Attachment #1: Type: text/plain, Size: 1526 bytes --]

Hello,

I recently startet using the ulogd daemon to log traffic from a PPPoE
interface (have used it on regular ethernet interfaces for long). In the
resulting logs, the MAC address was filled with (what seemed to be)
garbage like the following entry:

Oct 13 21:15:09 gw INPUT: IN=ppp0 OUT=
MAC=6b:21:c0:00:00:00:00:11:00:00:00:00:00:00:00:00:00:00:00:01:00:00:00:00:00:00:00:63:26:00:00:00:00:00:00:02:26:00:00:7d:26:00:00:00:00:00:00:00:80:8e:c6:00:80:8e:c6:00:00:00:00:00:00:00:00:00:00:00:00:a8:60:76:c1:a8:60:76:c1:00:00:00:00:0c:45:00:00:4e:75:63:00:00:72:11:5e:4f:c1:f9:05:05:50:3f:5d:af:04:01:00:89:00:3a:46:ba:01:00:00:10:00:01:00:00:00:00:00:00:20:43:4b:41:41:41:41:41:41:41:41:41:41:41:41:41:41:41:41:41:41:41:41:41:41:41:41:41:41:41:41:41:41:00:00:21:00:01:00:2c:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00 
SRC=vvv.xxx.yyy.zzz 249.5.5 DST=aaa.bbb.ccc.ddd LEN=78 TOS=00 PREC=0x00
TTL=114 ID=30051 PROTO=UDP SPT=1025 DPT=137 LEN=58

When using the regular LOG target, the MAC field was empty. I traced
this back to the ipt_ulog_target function in
net/ipv4/netfilter/ipt_ULOG.c in the kernel, where pm->mac_len in the
ulog_packet_msg_t struct is left uninitialized, when there is no MAC
address.

The attached patch fixes this. It is made against 2.4.19, and I have
verified, that it applies to 2.4.20-pre11 as well as the latest
patch-o-matic patches from CVS.

Regards,
Anders K. Pedersen

[-- Attachment #2: ulog-maclen.patch --]
[-- Type: text/plain, Size: 421 bytes --]

--- linux-2.4.19/net/ipv4/netfilter/ipt_ULOG.c.orig	Sun Oct 13 22:01:55 2002
+++ linux-2.4.19/net/ipv4/netfilter/ipt_ULOG.c	Sun Oct 13 22:01:55 2002
@@ -223,7 +223,8 @@
 	    && in->hard_header_len <= ULOG_MAC_LEN) {
 		memcpy(pm->mac, (*pskb)->mac.raw, in->hard_header_len);
 		pm->mac_len = in->hard_header_len;
-	}
+	} else
+		pm->mac_len = 0;
 
 	if (in)
 		strncpy(pm->indev_name, in->name, sizeof(pm->indev_name));