* Patch "tcp: take care of truncations done by sk_filter()" has been added to the 4.8-stable tree
@ 2016-11-18 10:37 gregkh
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From: gregkh @ 2016-11-18 10:37 UTC (permalink / raw)
To: edumazet, davem, gregkh, marco.gra, vdronov; +Cc: stable, stable-commits
This is a note to let you know that I've just added the patch titled
tcp: take care of truncations done by sk_filter()
to the 4.8-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:
tcp-take-care-of-truncations-done-by-sk_filter.patch
and it can be found in the queue-4.8 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 foo@baz Fri Nov 18 11:35:46 CET 2016
From: Eric Dumazet <edumazet@google.com>
Date: Thu, 10 Nov 2016 13:12:35 -0800
Subject: tcp: take care of truncations done by sk_filter()
From: Eric Dumazet <edumazet@google.com>
[ Upstream commit ac6e780070e30e4c35bd395acfe9191e6268bdd3 ]
With syzkaller help, Marco Grassi found a bug in TCP stack,
crashing in tcp_collapse()
Root cause is that sk_filter() can truncate the incoming skb,
but TCP stack was not really expecting this to happen.
It probably was expecting a simple DROP or ACCEPT behavior.
We first need to make sure no part of TCP header could be removed.
Then we need to adjust TCP_SKB_CB(skb)->end_seq
Many thanks to syzkaller team and Marco for giving us a reproducer.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Marco Grassi <marco.gra@gmail.com>
Reported-by: Vladis Dronov <vdronov@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
include/net/tcp.h | 1 +
net/ipv4/tcp_ipv4.c | 19 ++++++++++++++++++-
net/ipv6/tcp_ipv6.c | 6 ++++--
3 files changed, 23 insertions(+), 3 deletions(-)
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -1164,6 +1164,7 @@ static inline void tcp_prequeue_init(str
}
bool tcp_prequeue(struct sock *sk, struct sk_buff *skb);
+int tcp_filter(struct sock *sk, struct sk_buff *skb);
#undef STATE_TRACE
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -1537,6 +1537,21 @@ bool tcp_prequeue(struct sock *sk, struc
}
EXPORT_SYMBOL(tcp_prequeue);
+int tcp_filter(struct sock *sk, struct sk_buff *skb)
+{
+ struct tcphdr *th = (struct tcphdr *)skb->data;
+ unsigned int eaten = skb->len;
+ int err;
+
+ err = sk_filter_trim_cap(sk, skb, th->doff * 4);
+ if (!err) {
+ eaten -= skb->len;
+ TCP_SKB_CB(skb)->end_seq -= eaten;
+ }
+ return err;
+}
+EXPORT_SYMBOL(tcp_filter);
+
/*
* From tcp_input.c
*/
@@ -1648,8 +1663,10 @@ process:
nf_reset(skb);
- if (sk_filter(sk, skb))
+ if (tcp_filter(sk, skb))
goto discard_and_relse;
+ th = (const struct tcphdr *)skb->data;
+ iph = ip_hdr(skb);
skb->dev = NULL;
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -1228,7 +1228,7 @@ static int tcp_v6_do_rcv(struct sock *sk
if (skb->protocol == htons(ETH_P_IP))
return tcp_v4_do_rcv(sk, skb);
- if (sk_filter(sk, skb))
+ if (tcp_filter(sk, skb))
goto discard;
/*
@@ -1455,8 +1455,10 @@ process:
if (tcp_v6_inbound_md5_hash(sk, skb))
goto discard_and_relse;
- if (sk_filter(sk, skb))
+ if (tcp_filter(sk, skb))
goto discard_and_relse;
+ th = (const struct tcphdr *)skb->data;
+ hdr = ipv6_hdr(skb);
skb->dev = NULL;
Patches currently in stable-queue which might be from edumazet@google.com are
queue-4.8/net-__skb_flow_dissect-must-cap-its-return-value.patch
queue-4.8/tcp-take-care-of-truncations-done-by-sk_filter.patch
queue-4.8/net-clear-sk_err_soft-in-sk_clone_lock.patch
queue-4.8/dccp-do-not-release-listeners-too-soon.patch
queue-4.8/net-mangle-zero-checksum-in-skb_checksum_help.patch
queue-4.8/tcp-fix-return-value-for-partial-writes.patch
queue-4.8/ipv6-dccp-fix-out-of-bound-access-in-dccp_v6_err.patch
queue-4.8/ipv6-dccp-add-missing-bind_conflict-to-dccp_ipv6_mapped.patch
queue-4.8/tcp-fix-potential-memory-corruption.patch
queue-4.8/dccp-do-not-send-reset-to-already-closed-sockets.patch
queue-4.8/dccp-fix-out-of-bound-access-in-dccp_v4_err.patch
queue-4.8/sock-fix-sendmmsg-for-partial-sendmsg.patch
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2016-11-18 10:37 Patch "tcp: take care of truncations done by sk_filter()" has been added to the 4.8-stable tree gregkh
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