[66/82] Phonet: Correct header retrieval after pskb_may_pull

[66/82] Phonet: Correct header retrieval after pskb_may_pull

[Greg KH]

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2.6.35-stable review patch.  If anyone has any objections, please let us know.

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From: Kumar Sanghvi <kumar.sanghvi@stericsson.com>

[ Upstream commit a91e7d471e2e384035b9746ea707ccdcd353f5dd ]

Retrieve the header after doing pskb_may_pull since, pskb_may_pull
could change the buffer structure.

This is based on the comment given by Eric Dumazet on Phonet
Pipe controller patch for a similar problem.

Signed-off-by: Kumar Sanghvi <kumar.sanghvi@stericsson.com>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: Rémi Denis-Courmont <remi.denis-courmont@nokia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
 net/phonet/pep.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/net/phonet/pep.c
+++ b/net/phonet/pep.c
@@ -225,12 +225,13 @@ static void pipe_grant_credits(struct so
 static int pipe_rcv_status(struct sock *sk, struct sk_buff *skb)
 {
 	struct pep_sock *pn = pep_sk(sk);
-	struct pnpipehdr *hdr = pnp_hdr(skb);
+	struct pnpipehdr *hdr;
 	int wake = 0;
 
 	if (!pskb_may_pull(skb, sizeof(*hdr) + 4))
 		return -EINVAL;
 
+	hdr = pnp_hdr(skb);
 	if (hdr->data[0] != PN_PEP_TYPE_COMMON) {
 		LIMIT_NETDEBUG(KERN_DEBUG"Phonet unknown PEP type: %u\n",
 				(unsigned)hdr->data[0]);