Commit bceaa902 authored by Hannes Frederic Sowa's avatar Hannes Frederic Sowa Committed by David S. Miller
Browse files

inet: prevent leakage of uninitialized memory to user in recv syscalls 



Only update *addr_len when we actually fill in sockaddr, otherwise we
can return uninitialized memory from the stack to the caller in the
recvfrom, recvmmsg and recvmsg syscalls. Drop the the (addr_len == NULL)
checks because we only get called with a valid addr_len pointer either
from sock_common_recvmsg or inet_recvmsg.

If a blocking read waits on a socket which is concurrently shut down we
now return zero and set msg_msgnamelen to 0.

Reported-by: default avatarmpb <mpb.mail@gmail.com>
Suggested-by: default avatarEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: default avatarHannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent bcd081a3

net/ieee802154/dgram.c

+1 −2
Original line number Diff line number Diff line
@@ -315,9 +315,8 @@ static int dgram_recvmsg(struct kiocb *iocb, struct sock *sk, 
	if (saddr) {

		saddr->family = AF_IEEE802154;

		saddr->addr = mac_cb(skb)->sa;

	}

	if (addr_len)

		*addr_len = sizeof(*saddr);

	}



	if (flags & MSG_TRUNC)

		copied = skb->len;

net/ipv4/ping.c

+7 −12
Original line number Diff line number Diff line
@@ -830,8 +830,6 @@ int ping_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, 
{

	struct inet_sock *isk = inet_sk(sk);

	int family = sk->sk_family;

	struct sockaddr_in *sin;

	struct sockaddr_in6 *sin6;

	struct sk_buff *skb;

	int copied, err;
@@ -841,13 +839,6 @@ int ping_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, 
	if (flags & MSG_OOB)

		goto out;



	if (addr_len) {

		if (family == AF_INET)

			*addr_len = sizeof(*sin);

		else if (family == AF_INET6 && addr_len)

			*addr_len = sizeof(*sin6);

	}



	if (flags & MSG_ERRQUEUE) {

		if (family == AF_INET) {

			return ip_recv_error(sk, msg, len);
@@ -877,11 +868,13 @@ int ping_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, 


	/* Copy the address and add cmsg data. */

	if (family == AF_INET) {

		sin = (struct sockaddr_in *) msg->msg_name;

		struct sockaddr_in *sin = (struct sockaddr_in *)msg->msg_name;



		sin->sin_family = AF_INET;

		sin->sin_port = 0 /* skb->h.uh->source */;

		sin->sin_addr.s_addr = ip_hdr(skb)->saddr;

		memset(sin->sin_zero, 0, sizeof(sin->sin_zero));

		*addr_len = sizeof(*sin);



		if (isk->cmsg_flags)

			ip_cmsg_recv(msg, skb);
@@ -890,17 +883,19 @@ int ping_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, 
	} else if (family == AF_INET6) {

		struct ipv6_pinfo *np = inet6_sk(sk);

		struct ipv6hdr *ip6 = ipv6_hdr(skb);

		sin6 = (struct sockaddr_in6 *) msg->msg_name;

		struct sockaddr_in6 *sin6 =

			(struct sockaddr_in6 *)msg->msg_name;



		sin6->sin6_family = AF_INET6;

		sin6->sin6_port = 0;

		sin6->sin6_addr = ip6->saddr;



		sin6->sin6_flowinfo = 0;

		if (np->sndflow)

			sin6->sin6_flowinfo = ip6_flowinfo(ip6);



		sin6->sin6_scope_id = ipv6_iface_scope_id(&sin6->sin6_addr,

							  IP6CB(skb)->iif);

		*addr_len = sizeof(*sin6);



		if (inet6_sk(sk)->rxopt.all)

			pingv6_ops.ip6_datagram_recv_ctl(sk, msg, skb);

net/ipv4/raw.c

+1 −3
Original line number Diff line number Diff line
@@ -696,9 +696,6 @@ static int raw_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, 
	if (flags & MSG_OOB)

		goto out;



	if (addr_len)

		*addr_len = sizeof(*sin);



	if (flags & MSG_ERRQUEUE) {

		err = ip_recv_error(sk, msg, len);

		goto out;
@@ -726,6 +723,7 @@ static int raw_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, 
		sin->sin_addr.s_addr = ip_hdr(skb)->saddr;

		sin->sin_port = 0;

		memset(&sin->sin_zero, 0, sizeof(sin->sin_zero));

		*addr_len = sizeof(*sin);

	}

	if (inet->cmsg_flags)

		ip_cmsg_recv(msg, skb);

net/ipv4/udp.c

+1 −6
Original line number Diff line number Diff line
@@ -1235,12 +1235,6 @@ int udp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, 
	int is_udplite = IS_UDPLITE(sk);

	bool slow;



	/*

	 *	Check any passed addresses

	 */

	if (addr_len)

		*addr_len = sizeof(*sin);



	if (flags & MSG_ERRQUEUE)

		return ip_recv_error(sk, msg, len);
@@ -1302,6 +1296,7 @@ try_again: 
		sin->sin_port = udp_hdr(skb)->source;

		sin->sin_addr.s_addr = ip_hdr(skb)->saddr;

		memset(sin->sin_zero, 0, sizeof(sin->sin_zero));

		*addr_len = sizeof(*sin);

	}

	if (inet->cmsg_flags)

		ip_cmsg_recv(msg, skb);

net/ipv6/raw.c

+1 −3
Original line number Diff line number Diff line
@@ -465,9 +465,6 @@ static int rawv6_recvmsg(struct kiocb *iocb, struct sock *sk, 
	if (flags & MSG_OOB)

		return -EOPNOTSUPP;



	if (addr_len)

		*addr_len=sizeof(*sin6);



	if (flags & MSG_ERRQUEUE)

		return ipv6_recv_error(sk, msg, len);
@@ -506,6 +503,7 @@ static int rawv6_recvmsg(struct kiocb *iocb, struct sock *sk, 
		sin6->sin6_flowinfo = 0;

		sin6->sin6_scope_id = ipv6_iface_scope_id(&sin6->sin6_addr,

							  IP6CB(skb)->iif);

		*addr_len = sizeof(*sin6);

	}



	sock_recv_ts_and_drops(msg, sk, skb);

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