sctp: Free cookie before we memdup a new one

Based on comments from Xin, even after fixes for our recent syzbot
report of cookie memory leaks, its possible to get a resend of an INIT
chunk which would lead to us leaking cookie memory.

To ensure that we don't leak cookie memory, free any previously
allocated cookie first.

Change notes
v1->v2
update subsystem tag in subject (davem)
repeat kfree check for peer_random and peer_hmacs (xin)

v2->v3
net->sctp
also free peer_chunks

v3->v4
fix subject tags

v4->v5
remove cut line

Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
Reported-by: syzbot+f7e9153b037eac9b1df8@syzkaller.appspotmail.com
CC: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
CC: Xin Long <lucien.xin@gmail.com>
CC: "David S. Miller" <davem@davemloft.net>
CC: netdev@vger.kernel.org
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Neil Horman 2019-06-13 06:35:59 -04:00 committed by David S. Miller
parent 6bb9e376c2
commit ce950f1050

View File

@ -2583,6 +2583,8 @@ do_addr_param:
case SCTP_PARAM_STATE_COOKIE:
asoc->peer.cookie_len =
ntohs(param.p->length) - sizeof(struct sctp_paramhdr);
if (asoc->peer.cookie)
kfree(asoc->peer.cookie);
asoc->peer.cookie = kmemdup(param.cookie->body, asoc->peer.cookie_len, gfp);
if (!asoc->peer.cookie)
retval = 0;
@ -2647,6 +2649,8 @@ do_addr_param:
goto fall_through;
/* Save peer's random parameter */
if (asoc->peer.peer_random)
kfree(asoc->peer.peer_random);
asoc->peer.peer_random = kmemdup(param.p,
ntohs(param.p->length), gfp);
if (!asoc->peer.peer_random) {
@ -2660,6 +2664,8 @@ do_addr_param:
goto fall_through;
/* Save peer's HMAC list */
if (asoc->peer.peer_hmacs)
kfree(asoc->peer.peer_hmacs);
asoc->peer.peer_hmacs = kmemdup(param.p,
ntohs(param.p->length), gfp);
if (!asoc->peer.peer_hmacs) {
@ -2675,6 +2681,8 @@ do_addr_param:
if (!ep->auth_enable)
goto fall_through;
if (asoc->peer.peer_chunks)
kfree(asoc->peer.peer_chunks);
asoc->peer.peer_chunks = kmemdup(param.p,
ntohs(param.p->length), gfp);
if (!asoc->peer.peer_chunks)