ip: zero sockaddr returned on error queue

The sockaddr is returned in IP(V6)_RECVERR as part of errhdr. That
structure is defined and allocated on the stack as

    struct {
            struct sock_extended_err ee;
            struct sockaddr_in(6)    offender;
    } errhdr;

The second part is only initialized for certain SO_EE_ORIGIN values.
Always initialize it completely.

An MTU exceeded error on a SOCK_RAW/IPPROTO_RAW is one example that
would return uninitialized bytes.

Signed-off-by: Willem de Bruijn <willemb@google.com>
----

Also verified that there is no padding between errhdr.ee and
errhdr.offender that could leak additional kernel data.
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index 8a89c73..6b85adb 100644 (file)
--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -461,17 +461,13 @@ int ip_recv_error(struct sock *sk, struct msghdr *msg, int len, int *addr_len)
 
        memcpy(&errhdr.ee, &serr->ee, sizeof(struct sock_extended_err));
        sin = &errhdr.offender;
-       sin->sin_family = AF_UNSPEC;
+       memset(sin, 0, sizeof(*sin));
 
        if (serr->ee.ee_origin == SO_EE_ORIGIN_ICMP ||
            ipv4_pktinfo_prepare_errqueue(sk, skb, serr->ee.ee_origin)) {
-               struct inet_sock *inet = inet_sk(sk);
-
                sin->sin_family = AF_INET;
                sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
-               sin->sin_port = 0;
-               memset(&sin->sin_zero, 0, sizeof(sin->sin_zero));
-               if (inet->cmsg_flags)
+               if (inet_sk(sk)->cmsg_flags)
                        ip_cmsg_recv(msg, skb);
        }
 

diff --git a/net/ipv6/datagram.c b/net/ipv6/datagram.c
index 100c589..49f5e73 100644 (file)
--- a/net/ipv6/datagram.c
+++ b/net/ipv6/datagram.c
@@ -393,11 +393,10 @@ int ipv6_recv_error(struct sock *sk, struct msghdr *msg, int len, int *addr_len)
 
        memcpy(&errhdr.ee, &serr->ee, sizeof(struct sock_extended_err));
        sin = &errhdr.offender;
-       sin->sin6_family = AF_UNSPEC;
+       memset(sin, 0, sizeof(*sin));
+
        if (serr->ee.ee_origin != SO_EE_ORIGIN_LOCAL) {
                sin->sin6_family = AF_INET6;
-               sin->sin6_flowinfo = 0;
-               sin->sin6_port = 0;
                if (np->rxopt.all) {
                        if (serr->ee.ee_origin != SO_EE_ORIGIN_ICMP &&
                            serr->ee.ee_origin != SO_EE_ORIGIN_ICMP6)
@@ -412,12 +411,9 @@ int ipv6_recv_error(struct sock *sk, struct msghdr *msg, int len, int *addr_len)
                                ipv6_iface_scope_id(&sin->sin6_addr,
                                                    IP6CB(skb)->iif);
                } else {
-                       struct inet_sock *inet = inet_sk(sk);
-
                        ipv6_addr_set_v4mapped(ip_hdr(skb)->saddr,
                                               &sin->sin6_addr);
-                       sin->sin6_scope_id = 0;
-                       if (inet->cmsg_flags)
+                       if (inet_sk(sk)->cmsg_flags)
                                ip_cmsg_recv(msg, skb);
                }
        }