pve-kernel-lowlatency-qoup/CVE-2017-9242-ipv6-fix-out-of-bound-writes-in-__ip6_append_data.patch
Fabian Grünbichler 0f831b3cf2 add CVE fixes
CVE-2017-8890: dccp/tcp: do not inherit mc_list from parent
CVE-2017-9074: ipv6: Prevent overrun when parsing v6 header options
CVE-2017-9075: sctp: do not inherit ipv6_{mc|ac|fl}_list from parent
CVE-2017-9076/CVE-2017-9077: ipv6/dccp: do not inherit ipv6_mc_list from parent
CVE-2017-9242: ipv6: fix out of bound writes in __ip6_append_data()
2017-06-08 14:22:03 +02:00

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2.6 KiB
Diff

From 2bb2c56a2089211713a7b1fb379cce741f65ea9e Mon Sep 17 00:00:00 2001
From: Eric Dumazet <edumazet@google.com>
Date: Fri, 19 May 2017 14:17:48 -0700
Subject: [PATCH] ipv6: fix out of bound writes in __ip6_append_data()
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Andrey Konovalov and idaifish@gmail.com reported crashes caused by
one skb shared_info being overwritten from __ip6_append_data()
Andrey program lead to following state :
copy -4200 datalen 2000 fraglen 2040
maxfraglen 2040 alloclen 2048 transhdrlen 0 offset 0 fraggap 6200
The skb_copy_and_csum_bits(skb_prev, maxfraglen, data + transhdrlen,
fraggap, 0); is overwriting skb->head and skb_shared_info
Since we apparently detect this rare condition too late, move the
code earlier to even avoid allocating skb and risking crashes.
Once again, many thanks to Andrey and syzkaller team.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Andrey Konovalov <andreyknvl@google.com>
Tested-by: Andrey Konovalov <andreyknvl@google.com>
Reported-by: <idaifish@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
CVE-2017-9242
(cherry-picked from 232cd35d0804cc241eb887bb8d4d9b3b9881c64a)
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
Acked-by: Colin King <colin.king@canonical.com>
Acked-by: Andy Whitcroft <andy.whitcroft@canonical.com>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>
---
net/ipv6/ip6_output.c | 15 ++++++++-------
1 file changed, 8 insertions(+), 7 deletions(-)
diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index 8f0814d301aa..135ee573eaef 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -1463,6 +1463,11 @@ static int __ip6_append_data(struct sock *sk,
*/
alloclen += sizeof(struct frag_hdr);
+ copy = datalen - transhdrlen - fraggap;
+ if (copy < 0) {
+ err = -EINVAL;
+ goto error;
+ }
if (transhdrlen) {
skb = sock_alloc_send_skb(sk,
alloclen + hh_len,
@@ -1512,13 +1517,9 @@ static int __ip6_append_data(struct sock *sk,
data += fraggap;
pskb_trim_unique(skb_prev, maxfraglen);
}
- copy = datalen - transhdrlen - fraggap;
-
- if (copy < 0) {
- err = -EINVAL;
- kfree_skb(skb);
- goto error;
- } else if (copy > 0 && getfrag(from, data + transhdrlen, offset, copy, fraggap, skb) < 0) {
+ if (copy > 0 &&
+ getfrag(from, data + transhdrlen, offset,
+ copy, fraggap, skb) < 0) {
err = -EFAULT;
kfree_skb(skb);
goto error;
--
2.11.0