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authorEric Dumazet <edumazet@google.com>2018-07-07 23:00:01 -0700
committerDavid S. Miller <davem@davemloft.net>2018-07-08 16:56:33 +0900
commit6508b6781be076f889e3077a1a5fadf1930a569d (patch)
treedf0f6458ae9cad9b90fe0abe4dbda3dafa58ee42 /net/ipv4
parent7f93d1295131c9a8b6ff5eec13eef094f0d42921 (diff)
downloadlinux-6508b6781be076f889e3077a1a5fadf1930a569d.tar.bz2
tcp: cleanup copied_seq and urg_data in tcp_disconnect
tcp_zerocopy_receive() relies on tcp_inq() to limit number of bytes requested by user. syzbot found that after tcp_disconnect(), tcp_inq() was returning a stale value (number of bytes in queue before the disconnect). Note that after this patch, ioctl(fd, SIOCINQ, &val) is also fixed and returns 0, so this might be a candidate for all known linux kernels. While we are at this, we probably also should clear urg_data to avoid other syzkaller reports after it discovers how to deal with urgent data. syzkaller repro : socket(PF_INET, SOCK_STREAM, IPPROTO_IP) = 3 bind(3, {sa_family=AF_INET, sin_port=htons(20000), sin_addr=inet_addr("224.0.0.1")}, 16) = 0 connect(3, {sa_family=AF_INET, sin_port=htons(20000), sin_addr=inet_addr("127.0.0.1")}, 16) = 0 send(3, ..., 4096, 0) = 4096 connect(3, {sa_family=AF_UNSPEC, sa_data="\0\0\0\0\0\0\0\0\0\0\0\0\0\0"}, 128) = 0 getsockopt(3, SOL_TCP, TCP_ZEROCOPY_RECEIVE, ..., [16]) = 0 // CRASH Fixes: 05255b823a61 ("tcp: add TCP_ZEROCOPY_RECEIVE support for zerocopy receive") 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/ipv4')
-rw-r--r--net/ipv4/tcp.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index c959bb6ea4ed..0d43705dd001 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -2562,6 +2562,8 @@ int tcp_disconnect(struct sock *sk, int flags)
tcp_clear_xmit_timers(sk);
__skb_queue_purge(&sk->sk_receive_queue);
+ tp->copied_seq = tp->rcv_nxt;
+ tp->urg_data = 0;
tcp_write_queue_purge(sk);
tcp_fastopen_active_disable_ofo_check(sk);
skb_rbtree_purge(&tp->out_of_order_queue);