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: mpb <[email protected]>
Suggested-by: Eric Dumazet <[email protected]>
Signed-off-by: Hannes Frederic Sowa <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
This commit is contained in:
Hannes Frederic Sowa 2013-11-18 04:20:45 +01:00 • committed by David S. Miller
commit bceaa90240
8 changed files with 17 additions and 38 deletions

View file

@ -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);

View file

@ -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);

View file

@ -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);