Bernhard Schmidt wrote:
> I've hit another kernel oops with 2.6.20-rc3 on i386 platform. It is
> reproducible, as soon as I load nf_conntrack_ipv6 and try to send
> something large (scp or so) inside an OpenVPN tunnel on my client
> (patched with UDPv6 transport) the router (another box) OOPSes.
>
> tcpdump suggests the problem appears as soon as my client sends
> fragmented UDPv6 packets towards the destination. It does not happen
> when nf_conntrack_ipv6 is not loaded. This is the OOPS as dumped from
> the serial console:
>
> heimdall login: Oops: 0000 [#1]
> Modules linked in: sit sch_red sch_htb pppoe pppox ppp_generic slhc
> xt_CLASSIFY ipt_TOS xt_length ipt_tos ipt_TCPMSS xt_tcpudp
> ipt_MASQUERADE xt_state iptable_mangle iptable_filter
> iptable_nat nf_nat nf_conntrack_ipv4 ip_tables x_tables
> nf_conntrack_ipv6 nf_conntrack nfnetlink
> CPU: 0
> EIP: 0060:[<00000001>] Not tainted VLI
> EFLAGS: 00010246 (2.6.20-rc3 #2)
> EIP is at 0x1
> eax: cd215bc0 ebx: cd1f3160 ecx: cc59002a edx: cd215bc0
> esi: cd215bc0 edi: cd215bc0 ebp: 00000000 esp: c030bd3c
> ds: 007b es: 007b ss: 0068
> Process swapper (pid: 0, ti=c030a000 task=c02e93a0 task.ti=c030a000)
> Stack: c0212cc4 00000004 cc83f160 cd2130c0 cd215bc0 cd2130c0 cd215bc0
> c021734b
> c030bdb4 c0307a60 0000000a cceee800 cceee800 cd215bc0 cd1f3160
> 00000000
> c021896b c0307a60 cd215bc0 cd215bc0 cceee800 cd1f3160 c025f1c6
> 00000000
> Call Trace:
> [<c0212cc4>] __kfree_skb+0x84/0xe0
> [<c021734b>] dev_hard_start_xmit+0x1bb/0x1d0
> [<c021896b>] dev_queue_xmit+0x11b/0x1b0
> [<c025f1c6>] ip6_output2+0x276/0x2b0
> [<c025ed30>] ip6_output_finish+0x0/0xf0
> [<c025fc0a>] ip6_output+0x90a/0x940
> [<c013e9e5>] cache_alloc_refill+0x2c5/0x3f0
> [<c0212eed>] pskb_expand_head+0xdd/0x130
> [<c02608d5>] ip6_forward+0x465/0x4b0
> [<c02618c6>] ip6_rcv_finish+0x16/0x30
> [<ce81a056>] nf_ct_frag6_output+0x86/0xb0 [nf_conntrack_ipv6]
Does this patch help?
[NETFILTER]: nf_conntrack_ipv6: fix crash when handling fragments
When IPv6 connection tracking splits up a defragmented packet into
its original fragments, the packets are taken from a list and are
passed to the network stack with skb->next still set. This causes
dev_hard_start_xmit to treat them as GSO fragments, resulting in
a use after free when connection tracking handles the next fragment.
Signed-off-by: Patrick McHardy <[email protected]>
---
commit f7c932bb23afe7873586fb9bad82718e3f16a3af
tree c2e18743b831f43fa7859d29ea9b2a622c58da99
parent fe6df90eb909a84593b6902e6e4f802687bc4564
author Patrick McHardy <[email protected]> Tue, 09 Jan 2007 10:35:28 +0100
committer Patrick McHardy <[email protected]> Tue, 09 Jan 2007 10:35:28 +0100
net/ipv6/netfilter/nf_conntrack_reasm.c | 2 ++
1 files changed, 2 insertions(+), 0 deletions(-)
diff --git a/net/ipv6/netfilter/nf_conntrack_reasm.c b/net/ipv6/netfilter/nf_conntrack_reasm.c
index 37e5fca..d9c1540 100644
--- a/net/ipv6/netfilter/nf_conntrack_reasm.c
+++ b/net/ipv6/netfilter/nf_conntrack_reasm.c
@@ -835,6 +835,8 @@ void nf_ct_frag6_output(unsigned int hoo
s->nfct_reasm = skb;
s2 = s->next;
+ s->next = NULL;
+
NF_HOOK_THRESH(PF_INET6, hooknum, s, in, out, okfn,
NF_IP6_PRI_CONNTRACK_DEFRAG + 1);
s = s2;
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