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| author | Eric Dumazet <edumazet@google.com> | 2018-09-14 12:02:31 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2018-09-17 07:56:02 -0700 |
| commit | bbd6528d28c1b8e80832b3b018ec402b6f5c3215 (patch) | |
| tree | 4c7e9f26af82fd34dcbc6520091f046982388a10 /net | |
| parent | a7f38002fb69b44f8fc622ecb838665d0b8666af (diff) | |
| download | linux-bbd6528d28c1b8e80832b3b018ec402b6f5c3215.tar.gz linux-bbd6528d28c1b8e80832b3b018ec402b6f5c3215.tar.bz2 linux-bbd6528d28c1b8e80832b3b018ec402b6f5c3215.zip | |
ipv6: fix possible use-after-free in ip6_xmit()
In the unlikely case ip6_xmit() has to call skb_realloc_headroom(),
we need to call skb_set_owner_w() before consuming original skb,
otherwise we risk a use-after-free.
Bring IPv6 in line with what we do in IPv4 to fix this.
Fixes: 1da177e4c3f41 ("Linux-2.6.12-rc2")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
| -rw-r--r-- | net/ipv6/ip6_output.c | 6 |
1 files changed, 2 insertions, 4 deletions
diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c index 16f200f06500..f9f8f554d141 100644 --- a/net/ipv6/ip6_output.c +++ b/net/ipv6/ip6_output.c @@ -219,12 +219,10 @@ int ip6_xmit(const struct sock *sk, struct sk_buff *skb, struct flowi6 *fl6, kfree_skb(skb); return -ENOBUFS; } + if (skb->sk) + skb_set_owner_w(skb2, skb->sk); consume_skb(skb); skb = skb2; - /* skb_set_owner_w() changes sk->sk_wmem_alloc atomically, - * it is safe to call in our context (socket lock not held) - */ - skb_set_owner_w(skb, (struct sock *)sk); } if (opt->opt_flen) ipv6_push_frag_opts(skb, opt, &proto); |