diff options
| author | Christoph Paasch <cpaasch@apple.com> | 2019-03-11 11:41:05 -0700 |
|---|---|---|
| committer | Jason Liu <jason.hui.liu@nxp.com> | 2019-09-06 15:49:42 +0800 |
| commit | f5e7555bec7c27e19bb57d91ba21da394e25b3c9 (patch) | |
| tree | fcf23da00916f44cfb1ea4743d38d7cd8ad5deac /net/ipv4 | |
| parent | d90110eb9a49c1d877bf5262cbb94fba8e05f6f6 (diff) | |
tcp: Don't access TCP_SKB_CB before initializing it
[ Upstream commit f2feaefdabb0a6253aa020f65e7388f07a9ed47c ]
Since commit eeea10b83a13 ("tcp: add
tcp_v4_fill_cb()/tcp_v4_restore_cb()"), tcp_vX_fill_cb is only called
after tcp_filter(). That means, TCP_SKB_CB(skb)->end_seq still points to
the IP-part of the cb.
We thus should not mock with it, as this can trigger bugs (thanks
syzkaller):
[ 12.349396] ==================================================================
[ 12.350188] BUG: KASAN: slab-out-of-bounds in ip6_datagram_recv_specific_ctl+0x19b3/0x1a20
[ 12.351035] Read of size 1 at addr ffff88006adbc208 by task test_ip6_datagr/1799
Setting end_seq is actually no more necessary in tcp_filter as it gets
initialized later on in tcp_vX_fill_cb.
Cc: Eric Dumazet <edumazet@google.com>
Fixes: eeea10b83a13 ("tcp: add tcp_v4_fill_cb()/tcp_v4_restore_cb()")
Signed-off-by: Christoph Paasch <cpaasch@apple.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry picked from commit d51c4c0c1fbc338d1b756d9d9d1ba438534546cd)
Diffstat (limited to 'net/ipv4')
| -rw-r--r-- | net/ipv4/tcp_ipv4.c | 9 |
1 files changed, 1 insertions, 8 deletions
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index e593301f442f..97a414dbdaf4 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -1578,15 +1578,8 @@ EXPORT_SYMBOL(tcp_add_backlog); 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; + return sk_filter_trim_cap(sk, skb, th->doff * 4); } EXPORT_SYMBOL(tcp_filter); |