Commit 1e4b50f0 authored by Eugene Syromiatnikov's avatar Eugene Syromiatnikov Committed by Jakub Kicinski
Browse files

mctp: handle the struct sockaddr_mctp padding fields 



In order to have the padding fields actually usable in the future,
there have to be checks that user space doesn't supply non-zero garbage
there.  It is also worth setting these padding fields to zero, unless
it is known that they have been already zeroed.

Cc: stable@vger.kernel.org # v5.15
Fixes: 5a20dd46 ("mctp: Be explicit about struct sockaddr_mctp padding")
Signed-off-by: default avatarEugene Syromiatnikov <esyr@redhat.com>
Acked-by: default avatarJeremy Kerr <jk@codeconstruct.com.au>
Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent a5bda908

net/mctp/af_mctp.c

+13 −0
Original line number Diff line number Diff line
@@ -33,6 +33,12 @@ static int mctp_release(struct socket *sock) 
	return 0;

}



/* Generic sockaddr checks, padding checks only so far */

static bool mctp_sockaddr_is_ok(const struct sockaddr_mctp *addr)

{

	return !addr->__smctp_pad0 && !addr->__smctp_pad1;

}



static int mctp_bind(struct socket *sock, struct sockaddr *addr, int addrlen)

{

	struct sock *sk = sock->sk;
@@ -52,6 +58,9 @@ static int mctp_bind(struct socket *sock, struct sockaddr *addr, int addrlen) 
	/* it's a valid sockaddr for MCTP, cast and do protocol checks */

	smctp = (struct sockaddr_mctp *)addr;



	if (!mctp_sockaddr_is_ok(smctp))

		return -EINVAL;



	lock_sock(sk);



	/* TODO: allow rebind */
@@ -87,6 +96,8 @@ static int mctp_sendmsg(struct socket *sock, struct msghdr *msg, size_t len) 
			return -EINVAL;

		if (addr->smctp_family != AF_MCTP)

			return -EINVAL;

		if (!mctp_sockaddr_is_ok(addr))

			return -EINVAL;

		if (addr->smctp_tag & ~(MCTP_TAG_MASK | MCTP_TAG_OWNER))

			return -EINVAL;
@@ -198,11 +209,13 @@ static int mctp_recvmsg(struct socket *sock, struct msghdr *msg, size_t len, 


		addr = msg->msg_name;

		addr->smctp_family = AF_MCTP;

		addr->__smctp_pad0 = 0;

		addr->smctp_network = cb->net;

		addr->smctp_addr.s_addr = hdr->src;

		addr->smctp_type = type;

		addr->smctp_tag = hdr->flags_seq_tag &

					(MCTP_HDR_TAG_MASK | MCTP_HDR_FLAG_TO);

		addr->__smctp_pad1 = 0;

		msg->msg_namelen = sizeof(*addr);



		if (msk->addr_ext) {