[PATCH 3.11 30/66] connector: use nlmsg_len() to check message length

Greg Kroah-Hartman
2013-11-01T22:22:29Z

From: Mathias Krause <minipli@googlemail.com>

[ Upstream commit 162b2bedc084d2d908a04c93383ba02348b648b0 ]

The current code tests the length of the whole netlink message to be
at least as long to fit a cn_msg. This is wrong as nlmsg_len includes
the length of the netlink message header. Use nlmsg_len() instead to
fix this "off-by-NLMSG_HDRLEN" size check.

Signed-off-by: Mathias Krause <minipli@googlemail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/connector/connector.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)

--- a/drivers/connector/connector.c
+++ b/drivers/connector/connector.c
@@ -157,17 +157,18 @@ static int cn_call_callback(struct sk_bu
static void cn_rx_skb(struct sk_buff *__skb)
{
struct nlmsghdr *nlh;
- int err;
struct sk_buff *skb;
+ int len, err;

skb = skb_get(__skb);

if (skb->len >= NLMSG_HDRLEN) {
nlh = nlmsg_hdr(skb);
+ len = nlmsg_len(nlh);

- if (nlh->nlmsg_len < sizeof(struct cn_msg) ||
+ if (len < (int)sizeof(struct cn_msg) ||
skb->len < nlh->nlmsg_len ||
- nlh->nlmsg_len > CONNECTOR_MAX_MSG_SIZE) {
+ len > CONNECTOR_MAX_MSG_SIZE) {
kfree_skb(skb);
return;
}