inet: prevent leakage of uninitialized memory to user in recv syscalls
[ Upstream commit bceaa90240b6019ed73b49965eac7d167610be69 ]
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 <mpb.mail@gmail.com>
Suggested-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index f79bfdb..3215075 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -348,9 +348,6 @@
int is_udp4;
bool slow;
- if (addr_len)
- *addr_len=sizeof(struct sockaddr_in6);
-
if (flags & MSG_ERRQUEUE)
return ipv6_recv_error(sk, msg, len);
@@ -423,7 +420,7 @@
if (ipv6_addr_type(&sin6->sin6_addr) & IPV6_ADDR_LINKLOCAL)
sin6->sin6_scope_id = IP6CB(skb)->iif;
}
-
+ *addr_len = sizeof(*sin6);
}
if (is_udp4) {
if (inet->cmsg_flags)