On Thu, Apr 26, 2018 at 02:13:57PM +0800, Xin Long wrote:
> 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
>
>
Acked-by: Neil Horman <nhorman@xxxxxxxxxxxxx>
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