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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: 5a20dd46b8 ("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>
This commit is contained in:
Eugene Syromiatnikov 2021-11-03 20:09:42 +01:00 committed by Jakub Kicinski
parent a5bda90884
commit 1e4b50f06d
1 changed files with 13 additions and 0 deletions
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13
net/mctp/af_mctp.c
View File

@ -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) {