[PATCH 3.12 31/83] net: add BUG_ON if kernel advertises msg_namelen > sizeof(struct sockaddr_storage)

Greg Kroah-Hartman
2013-12-06T22:37:39Z

From: Hannes Frederic Sowa <hannes@stressinduktion.org>

[ Upstream commit 68c6beb373955da0886d8f4f5995b3922ceda4be ]

In that case it is probable that kernel code overwrote part of the
stack. So we should bail out loudly here.

The BUG_ON may be removed in future if we are sure all protocols are
conformant.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/socket.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

--- a/net/socket.c
+++ b/net/socket.c
@@ -221,12 +221,13 @@ static int move_addr_to_user(struct sock
int err;
int len;

+ BUG_ON(klen > sizeof(struct sockaddr_storage));
err = get_user(len, ulen);
if (err)
return err;
if (len > klen)
len = klen;
- if (len < 0 || len > sizeof(struct sockaddr_storage))
+ if (len < 0)
return -EINVAL;
if (len) {
if (audit_sockaddr(klen, kaddr))