From: Eugene Syromiatnikov esyr@redhat.com
commit 1e4b50f06d970d8da3474d2a0354450416710bda upstream.
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: 5a20dd46b8b84593 ("mctp: Be explicit about struct sockaddr_mctp padding") Signed-off-by: Eugene Syromiatnikov esyr@redhat.com Acked-by: Jeremy Kerr jk@codeconstruct.com.au Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/mctp/af_mctp.c | 13 +++++++++++++ 1 file changed, 13 insertions(+)
--- a/net/mctp/af_mctp.c +++ b/net/mctp/af_mctp.c @@ -30,6 +30,12 @@ static int mctp_release(struct socket *s 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; @@ -49,6 +55,9 @@ static int mctp_bind(struct socket *sock /* 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 */ @@ -83,6 +92,8 @@ static int mctp_sendmsg(struct socket *s 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;
@@ -172,11 +183,13 @@ static int mctp_recvmsg(struct socket *s
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); }