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 1071ec9d453a ("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: 1071ec9d453a ("sctp: do not check port in sctp_inet6_cmp_addr")
Reported-by: syzbot+cd494c1dd681d4d93ebb@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Xin Long <lucien.xin@xxxxxxxxx>
---
net/sctp/ipv6.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/net/sctp/ipv6.c b/net/sctp/ipv6.c
index 2e3f7b7..4224711 100644
--- a/net/sctp/ipv6.c
+++ b/net/sctp/ipv6.c
@@ -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);
}
--
2.1.0
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