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

@ -139,9 +139,6 @@ static int pn_recvmsg(struct kiocb *iocb, struct sock *sk,
MSG_CMSG_COMPAT))
goto out_nofree;
if (addr_len)
*addr_len = sizeof(sa);
skb = skb_recv_datagram(sk, flags, noblock, &rval);
if (skb == NULL)
goto out_nofree;
@ -162,8 +159,10 @@ static int pn_recvmsg(struct kiocb *iocb, struct sock *sk,
rval = (flags & MSG_TRUNC) ? skb->len : copylen;
if (msg->msg_name != NULL)
memcpy(msg->msg_name, &sa, sizeof(struct sockaddr_pn));
if (msg->msg_name != NULL) {
memcpy(msg->msg_name, &sa, sizeof(sa));
*addr_len = sizeof(sa);
}
out:
skb_free_datagram(sk, skb);