[PATCH 3.8 19/91] net: add BUG_ON if kernel advertises msg_namelen > sizeof(struct sockaddr_storage)

From: Kamal Mostafa
Date: Thu Jan 02 2014 - 12:31:56 EST -stable review patch. If anyone has any objections, please let me know.


From: Hannes Frederic Sowa <hannes@xxxxxxxxxxxxxxxxxxx>

[ 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

Suggested-by: Eric Dumazet <eric.dumazet@xxxxxxxxx>
Signed-off-by: Hannes Frederic Sowa <hannes@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Kamal Mostafa <kamal@xxxxxxxxxxxxx>
net/socket.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/socket.c b/net/socket.c
index 5b1b9bd..f7129f3 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -216,12 +216,13 @@ static int move_addr_to_user(struct sockaddr_storage *kaddr, int klen,
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))

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