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Commit 8f659a03 authored by Mohamed Ghannam's avatar Mohamed Ghannam Committed by David S. Miller
Browse files

net: ipv4: fix for a race condition in raw_sendmsg 



inet->hdrincl is racy, and could lead to uninitialized stack pointer
usage, so its value should be read only once.

Fixes: c008ba5b ("ipv4: Avoid reading user iov twice after raw_probe_proto_opt")
Signed-off-by: default avatarMohamed Ghannam <simo.ghannam@gmail.com>
Reviewed-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 93c64764

net/ipv4/raw.c

+10 −5
Original line number Diff line number Diff line
@@ -513,11 +513,16 @@ static int raw_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) 
	int err;

	struct ip_options_data opt_copy;

	struct raw_frag_vec rfv;

	int hdrincl;



	err = -EMSGSIZE;

	if (len > 0xFFFF)

		goto out;



	/* hdrincl should be READ_ONCE(inet->hdrincl)

	 * but READ_ONCE() doesn't work with bit fields

	 */

	hdrincl = inet->hdrincl;

	/*

	 *	Check the flags.

	 */
@@ -593,7 +598,7 @@ static int raw_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) 
		/* Linux does not mangle headers on raw sockets,

		 * so that IP options + IP_HDRINCL is non-sense.

		 */

		if (inet->hdrincl)

		if (hdrincl)

			goto done;

		if (ipc.opt->opt.srr) {

			if (!daddr)
@@ -615,12 +620,12 @@ static int raw_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) 


	flowi4_init_output(&fl4, ipc.oif, sk->sk_mark, tos,

			   RT_SCOPE_UNIVERSE,

			   inet->hdrincl ? IPPROTO_RAW : sk->sk_protocol,

			   hdrincl ? IPPROTO_RAW : sk->sk_protocol,

			   inet_sk_flowi_flags(sk) |

			    (inet->hdrincl ? FLOWI_FLAG_KNOWN_NH : 0),

			    (hdrincl ? FLOWI_FLAG_KNOWN_NH : 0),

			   daddr, saddr, 0, 0, sk->sk_uid);



	if (!inet->hdrincl) {

	if (!hdrincl) {

		rfv.msg = msg;

		rfv.hlen = 0;
@@ -645,7 +650,7 @@ static int raw_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) 
		goto do_confirm;

back_from_confirm:



	if (inet->hdrincl)

	if (hdrincl)

		err = raw_send_hdrinc(sk, &fl4, msg, len,

				      &rt, msg->msg_flags, &ipc.sockc);