diff options
| author | Neil Horman | 2018-03-12 14:15:25 -0400 |
|---|---|---|
| committer | David S. Miller | 2018-03-15 14:32:04 -0400 |
| commit | 0aee4c259849099cb07ead6cd7fff74e561d5225 (patch) | |
| tree | 0b761fc60e6c92238be5bdcae3cc129e68178f93 /net/sctp/socket.c | |
| parent | 0c3d5a96d5e5e6d5662d335a3bdfb76f35433f18 (diff) | |
sctp: Fix double free in sctp_sendmsg_to_asoc
syzbot/kasan detected a double free in sctp_sendmsg_to_asoc:
BUG: KASAN: use-after-free in sctp_association_free+0x7b7/0x930
net/sctp/associola.c:332
Read of size 8 at addr ffff8801d8006ae0 by task syzkaller914861/4202
CPU: 1 PID: 4202 Comm: syzkaller914861 Not tainted 4.16.0-rc4+ #258
Hardware name: Google Google Compute Engine/Google Compute Engine
01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:17 [inline]
dump_stack+0x194/0x24d lib/dump_stack.c:53
print_address_description+0x73/0x250 mm/kasan/report.c:256
kasan_report_error mm/kasan/report.c:354 [inline]
kasan_report+0x23c/0x360 mm/kasan/report.c:412
__asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433
sctp_association_free+0x7b7/0x930 net/sctp/associola.c:332
sctp_sendmsg+0xc67/0x1a80 net/sctp/socket.c:2075
inet_sendmsg+0x11f/0x5e0 net/ipv4/af_inet.c:763
sock_sendmsg_nosec net/socket.c:629 [inline]
sock_sendmsg+0xca/0x110 net/socket.c:639
SYSC_sendto+0x361/0x5c0 net/socket.c:1748
SyS_sendto+0x40/0x50 net/socket.c:1716
do_syscall_64+0x281/0x940 arch/x86/entry/common.c:287
entry_SYSCALL_64_after_hwframe+0x42/0xb7
This was introduced by commit:
f84af33 sctp: factor out sctp_sendmsg_to_asoc from sctp_sendmsg
As the newly refactored function moved the wait_for_sndbuf call to a
point after the association was connected, allowing for peeloff events
to occur, which in turn caused wait_for_sndbuf to return -EPIPE which
was not caught by the logic that determines if an association should be
freed or not.
Fix it the easy way by returning the ordering of
sctp_primitive_ASSOCIATE and sctp_wait_for_sndbuf to the old order, to
ensure that EPIPE will not happen.
Tested by myself using the syzbot reproducers with positive results
Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
CC: davem@davemloft.net
CC: Xin Long <lucien.xin@gmail.com>
Reported-by: syzbot+a4e4112c3aff00c8cfd8@syzkaller.appspotmail.com
Reviewed-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/sctp/socket.c')
| -rw-r--r-- | net/sctp/socket.c | 26 |
1 files changed, 13 insertions, 13 deletions
diff --git a/net/sctp/socket.c b/net/sctp/socket.c index aeecdd620c45..7a10ae3c3d82 100644 --- a/net/sctp/socket.c +++ b/net/sctp/socket.c @@ -1883,6 +1883,19 @@ static int sctp_sendmsg_to_asoc(struct sctp_association *asoc, goto err; } + if (asoc->pmtu_pending) + sctp_assoc_pending_pmtu(asoc); + + if (sctp_wspace(asoc) < msg_len) + sctp_prsctp_prune(asoc, sinfo, msg_len - sctp_wspace(asoc)); + + if (!sctp_wspace(asoc)) { + timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT); + err = sctp_wait_for_sndbuf(asoc, &timeo, msg_len); + if (err) + goto err; + } + if (sctp_state(asoc, CLOSED)) { err = sctp_primitive_ASSOCIATE(net, asoc, NULL); if (err) @@ -1900,19 +1913,6 @@ static int sctp_sendmsg_to_asoc(struct sctp_association *asoc, pr_debug("%s: we associated primitively\n", __func__); } - if (asoc->pmtu_pending) - sctp_assoc_pending_pmtu(asoc); - - if (sctp_wspace(asoc) < msg_len) - sctp_prsctp_prune(asoc, sinfo, msg_len - sctp_wspace(asoc)); - - if (!sctp_wspace(asoc)) { - timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT); - err = sctp_wait_for_sndbuf(asoc, &timeo, msg_len); - if (err) - goto err; - } - datamsg = sctp_datamsg_from_user(asoc, sinfo, &msg->msg_iter); if (IS_ERR(datamsg)) { err = PTR_ERR(datamsg); |