[38/66] Phonet: Correct header retrieval after pskb_may_pull

[Greg KH]

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

------------------


From: Kumar Sanghvi <kumar.sanghvi@xxxxxxxxxxxxxx>

[ 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@xxxxxxxxxxxxxx>
Acked-by: Linus Walleij <linus.walleij@xxxxxxxxxxxxxx>
Acked-by: Eric Dumazet <eric.dumazet@xxxxxxxxx>
Acked-by: Rémi Denis-Courmont <remi.denis-courmont@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>
---
 net/phonet/pep.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/net/phonet/pep.c
+++ b/net/phonet/pep.c
@@ -224,12 +224,13 @@ 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]);


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