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>
diff --git a/net/ipv4/ping.c b/net/ipv4/ping.c
index 9afbdb1..aacefa0 100644
--- a/net/ipv4/ping.c
+++ b/net/ipv4/ping.c
@@ -830,8 +830,6 @@
{
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 @@
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 @@
/* 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 @@
} 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);