This is a note to let you know that I've just added the patch titled
ipv4: ip_check_defrag must not modify skb before unsharing
to the 3.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
ipv4-ip_check_defrag-must-not-modify-skb-before-unsharing.patch
and it can be found in the queue-3.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.
>From 62c30ed6c731bf4a9961856dffee55b2c8f89119 Mon Sep 17 00:00:00 2001
From: Johannes Berg <johannes.b...@intel.com>
Date: Sun, 9 Dec 2012 23:41:06 +0000
Subject: ipv4: ip_check_defrag must not modify skb before unsharing
From: Johannes Berg <johannes.b...@intel.com>
[ Upstream commit 1bf3751ec90cc3174e01f0d701e8449ce163d113 ]
ip_check_defrag() might be called from af_packet within the
RX path where shared SKBs are used, so it must not modify
the input SKB before it has unshared it for defragmentation.
Use skb_copy_bits() to get the IP header and only pull in
everything later.
The same is true for the other caller in macvlan as it is
called from dev->rx_handler which can also get a shared SKB.
Reported-by: Eric Leblond <e...@regit.org>
Cc: stable@vger.kernel.org
Signed-off-by: Johannes Berg <johannes.b...@intel.com>
Signed-off-by: David S. Miller <da...@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
net/ipv4/ip_fragment.c | 19 +++++++++----------
1 file changed, 9 insertions(+), 10 deletions(-)
--- a/net/ipv4/ip_fragment.c
+++ b/net/ipv4/ip_fragment.c
@@ -685,28 +685,27 @@ EXPORT_SYMBOL(ip_defrag);
struct sk_buff *ip_check_defrag(struct sk_buff *skb, u32 user)
{
- const struct iphdr *iph;
+ struct iphdr iph;
u32 len;
if (skb->protocol != htons(ETH_P_IP))
return skb;
- if (!pskb_may_pull(skb, sizeof(struct iphdr)))
+ if (!skb_copy_bits(skb, 0, &iph, sizeof(iph)))
return skb;
- iph = ip_hdr(skb);
- if (iph->ihl < 5 || iph->version != 4)
+ if (iph.ihl < 5 || iph.version != 4)
return skb;
- if (!pskb_may_pull(skb, iph->ihl*4))
- return skb;
- iph = ip_hdr(skb);
- len = ntohs(iph->tot_len);
- if (skb->len < len || len < (iph->ihl * 4))
+
+ len = ntohs(iph.tot_len);
+ if (skb->len < len || len < (iph.ihl * 4))
return skb;
- if (ip_is_fragment(ip_hdr(skb))) {
+ if (ip_is_fragment(&iph)) {
skb = skb_share_check(skb, GFP_ATOMIC);
if (skb) {
+ if (!pskb_may_pull(skb, iph.ihl*4))
+ return skb;
if (pskb_trim_rcsum(skb, len))
return skb;
memset(IPCB(skb), 0, sizeof(struct inet_skb_parm));
Patches currently in stable-queue which might be from johannes.b...@intel.com
are
queue-3.4/ipv4-ip_check_defrag-must-not-modify-skb-before-unsharing.patch
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