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authorHannes Frederic Sowa <hannes@stressinduktion.org>2013-11-18 04:20:45 +0100
committerDavid S. Miller <davem@davemloft.net>2013-11-18 15:12:03 -0500
commitbceaa90240b6019ed73b49965eac7d167610be69 (patch)
treef68c10948efff147a7b987369f1e720ad76f411b /net/ipv4/udp.c
parentbcd081a3aef1f7f3786067ae8dd26aaa1cf85153 (diff)
downloadlinux-bceaa90240b6019ed73b49965eac7d167610be69.tar.bz2
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 <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>
Diffstat (limited to 'net/ipv4/udp.c')
-rw-r--r--net/ipv4/udp.c7
1 files changed, 1 insertions, 6 deletions
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 89909dd730dd..998431cd471a 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -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);