Commit d625329b authored Apr 26, 2018 by Xin Long Committed by David S. Miller Apr 27, 2018

sctp: handle two v4 addrs comparison in sctp_inet6_cmp_addr



Since sctp ipv6 socket also supports v4 addrs, it's possible to
compare two v4 addrs in pf v6 .cmp_addr, sctp_inet6_cmp_addr.

However after Commit 1071ec9d ("sctp: do not check port in
sctp_inet6_cmp_addr"), it no longer calls af1->cmp_addr, which
in this case is sctp_v4_cmp_addr, but calls __sctp_v6_cmp_addr
where it handles them as two v6 addrs. It would cause a out of
bounds crash.

syzbot found this crash when trying to bind two v4 addrs to a
v6 socket.

This patch fixes it by adding the process for two v4 addrs in
sctp_inet6_cmp_addr.

Fixes: 1071ec9d ("sctp: do not check port in sctp_inet6_cmp_addr")
Reported-by:  <syzbot+cd494c1dd681d4d93ebb@syzkaller.appspotmail.com>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 1f3ccc3c

net/sctp/ipv6.c

+3 −0

Original line number	Diff line number	Diff line
		@@ -895,6 +895,9 @@ static int sctp_inet6_cmp_addr(const union sctp_addr *addr1,
		if (sctp_is_any(sk, addr1) \|\| sctp_is_any(sk, addr2))
		return 1;

		if (addr1->sa.sa_family == AF_INET && addr2->sa.sa_family == AF_INET)
		return addr1->v4.sin_addr.s_addr == addr2->v4.sin_addr.s_addr;

		return __sctp_v6_cmp_addr(addr1, addr2);
		}

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