net: fix a kernel infoleak in x25 module

commit 79e48650320e6fba48369fccf13fd045315b19b8 upstream.

Stack object "dte_facilities" is allocated in x25_rx_call_request(),
which is supposed to be initialized in x25_negotiate_facilities.
However, 5 fields (8 bytes in total) are not initialized. This
object is then copied to userland via copy_to_user, thus infoleak
occurs.

Signed-off-by: Kangjie Lu <kjlu@gatech.edu>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/net/x25/x25_facilities.c b/net/x25/x25_facilities.c
index 36384a1..887749c 100644 (file)
--- a/net/x25/x25_facilities.c
+++ b/net/x25/x25_facilities.c
@@ -271,6 +271,7 @@ int x25_negotiate_facilities(struct sk_buff *skb, struct sock *sk,
 
        memset(&theirs, 0, sizeof(theirs));
        memcpy(new, ours, sizeof(*new));
 
        memset(&theirs, 0, sizeof(theirs));
        memcpy(new, ours, sizeof(*new));

+       memset(dte, 0, sizeof(*dte));

 
        len = x25_parse_facilities(skb, &theirs, dte, &x25->vc_facil_mask);
        if (len < 0)
 
        len = x25_parse_facilities(skb, &theirs, dte, &x25->vc_facil_mask);
        if (len < 0)