connector: use nlmsg_len() to check message length

[ 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.

Cc: stable@vger.kernel.org  # v2.6.14+
Signed-off-by: Mathias Krause <minipli@googlemail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/drivers/connector/connector.c b/drivers/connector/connector.c
index dde6a0f..ea6efe8 100644 (file)
--- a/drivers/connector/connector.c
+++ b/drivers/connector/connector.c
@@ -157,17 +157,18 @@ static int cn_call_callback(struct sk_buff *skb)
 static void cn_rx_skb(struct sk_buff *__skb)
 {
        struct nlmsghdr *nlh;
 static void cn_rx_skb(struct sk_buff *__skb)
 {
        struct nlmsghdr *nlh;

-       int err;

        struct sk_buff *skb;
        struct sk_buff *skb;

+       int len, err;

 
        skb = skb_get(__skb);
 
        if (skb->len >= NLMSG_SPACE(0)) {
                nlh = nlmsg_hdr(skb);
 
        skb = skb_get(__skb);
 
        if (skb->len >= NLMSG_SPACE(0)) {
                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 ||
                    skb->len < nlh->nlmsg_len ||

-                   nlh->nlmsg_len > CONNECTOR_MAX_MSG_SIZE) {
+                   len > CONNECTOR_MAX_MSG_SIZE) {

                        kfree_skb(skb);
                        return;
                }
                        kfree_skb(skb);
                        return;
                }