netdev - [PATCH] skbuff: don't corrupt mac

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <20090617151734.5ce02459@nehalam>
Date:	Wed, 17 Jun 2009 15:17:34 -0700
From:	Stephen Hemminger <shemminger@...tta.com>
To:	Arnaldo Carvalho de Melo <acme@...stprotocols.net>,
	David Miller <davem@...emloft.net>
Cc:	netdev@...r.kernel.org
Subject: [PATCH] skbuff:  don't corrupt mac_header on skb expansion

The skb mac_header field is sometimes NULL (or ~0u) as a sentinel
value. The places where skb is expanded add an offset which would
change this flag into an invalid pointer (or offset).

Signed-off-by: Stephen Hemminger <shemminger@...tta.com>

--- a/net/core/skbuff.c	2009-06-17 15:02:19.208725168 -0700
+++ b/net/core/skbuff.c	2009-06-17 15:04:50.139435754 -0700
@@ -657,7 +657,8 @@ static void copy_skb_header(struct sk_bu
 	/* {transport,network,mac}_header are relative to skb->head */
 	new->transport_header += offset;
 	new->network_header   += offset;
-	new->mac_header	      += offset;
+	if (skb_mac_header_was_set(new))
+		new->mac_header	      += offset;
 #endif
 	skb_shinfo(new)->gso_size = skb_shinfo(old)->gso_size;
 	skb_shinfo(new)->gso_segs = skb_shinfo(old)->gso_segs;
@@ -839,7 +840,8 @@ int pskb_expand_head(struct sk_buff *skb
 	skb->tail	      += off;
 	skb->transport_header += off;
 	skb->network_header   += off;
-	skb->mac_header	      += off;
+	if (skb_mac_header_was_set(skb))
+		skb->mac_header += off;
 	skb->csum_start       += nhead;
 	skb->cloned   = 0;
 	skb->hdr_len  = 0;
@@ -931,7 +933,8 @@ struct sk_buff *skb_copy_expand(const st
 #ifdef NET_SKBUFF_DATA_USES_OFFSET
 	n->transport_header += off;
 	n->network_header   += off;
-	n->mac_header	    += off;
+	if (skb_mac_header_was_set(skb))
+		n->mac_header += off;
 #endif
 
 	return n;
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html