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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>
This commit is contained in:
Willem de Bruijn 2015-01-15 13:18:40 -05:00 committed by David S. Miller
parent 4315ef8d8b
commit f812116b17
2 changed files with 5 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
net/ipv4/ip_sockglue.c
View File

@ -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);
}

10
net/ipv6/datagram.c
View File

@ -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);
}
}