Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932087AbXKOGos (ORCPT ); Thu, 15 Nov 2007 01:44:48 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1761428AbXKOGmt (ORCPT ); Thu, 15 Nov 2007 01:42:49 -0500 Received: from pentafluge.infradead.org ([213.146.154.40]:55094 "EHLO pentafluge.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760859AbXKOGmq (ORCPT ); Thu, 15 Nov 2007 01:42:46 -0500 Date: Wed, 14 Nov 2007 22:40:22 -0800 From: Greg KH To: linux-kernel@vger.kernel.org, stable@kernel.org Cc: Justin Forbes , Zwane Mwaikambo , "Theodore Ts'o" , Randy Dunlap , Dave Jones , Chuck Wolber , Chris Wedgwood , Michael Krufky , Chuck Ebbert , Domenico Andreoli , torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, bunk@kernel.org, James Chapman , "David S. Miller" Subject: [patch 07/16] Fix L2TP oopses. Message-ID: <20071115064022.GG18951@kroah.com> References: <20071115060353.071060513@mini.kroah.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline; filename="fix-l2tp-oopses.patch" In-Reply-To: <20071115063921.GA18827@kroah.com> User-Agent: Mutt/1.5.16 (2007-06-09) X-Bad-Reply: References and In-Reply-To but no 'Re:' in Subject. Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3439 Lines: 116 -stable review patch. If anyone has any objections, please let us know. ------------------ From: James Chapman changeset 91781004b9c029ee55b7aa9ef950a373ba865dc6 in mainline. [PPP]: L2TP: Fix oops in transmit and receive paths Changes made on 18-sep to fix skb handling in the pppol2tp driver broke the transmit and receive paths. Users are only running into this now because distros are now using 2.6.23 and I must have messed up when I tested the change. For receive, we now do our own calculation of how much to pull from the skb (variable length L2TP header) rather than using skb_transport_offset(). Also, if the skb isn't a data packet, it must be passed back to UDP with skb->data pointing to the UDP header. For transmit, make sure skb->sk is set up because ip_queue_xmit() needs it. Signed-off-by: James Chapman Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- drivers/net/pppol2tp.c | 25 ++++++++++++++++++------- 1 file changed, 18 insertions(+), 7 deletions(-) --- a/drivers/net/pppol2tp.c +++ b/drivers/net/pppol2tp.c @@ -487,7 +487,7 @@ static int pppol2tp_recv_core(struct soc { struct pppol2tp_session *session = NULL; struct pppol2tp_tunnel *tunnel; - unsigned char *ptr; + unsigned char *ptr, *optr; u16 hdrflags; u16 tunnel_id, session_id; int length; @@ -495,7 +495,7 @@ static int pppol2tp_recv_core(struct soc tunnel = pppol2tp_sock_to_tunnel(sock); if (tunnel == NULL) - goto error; + goto no_tunnel; /* UDP always verifies the packet length. */ __skb_pull(skb, sizeof(struct udphdr)); @@ -508,7 +508,7 @@ static int pppol2tp_recv_core(struct soc } /* Point to L2TP header */ - ptr = skb->data; + optr = ptr = skb->data; /* Get L2TP header flags */ hdrflags = ntohs(*(__be16*)ptr); @@ -636,12 +636,14 @@ static int pppol2tp_recv_core(struct soc /* If offset bit set, skip it. */ if (hdrflags & L2TP_HDRFLAG_O) { offset = ntohs(*(__be16 *)ptr); - skb->transport_header += 2 + offset; - if (!pskb_may_pull(skb, skb_transport_offset(skb) + 2)) - goto discard; + ptr += 2 + offset; } - __skb_pull(skb, skb_transport_offset(skb)); + offset = ptr - optr; + if (!pskb_may_pull(skb, offset)) + goto discard; + + __skb_pull(skb, offset); /* Skip PPP header, if present. In testing, Microsoft L2TP clients * don't send the PPP header (PPP header compression enabled), but @@ -651,6 +653,9 @@ static int pppol2tp_recv_core(struct soc * Note that skb->data[] isn't dereferenced from a u16 ptr here since * the field may be unaligned. */ + if (!pskb_may_pull(skb, 2)) + goto discard; + if ((skb->data[0] == 0xff) && (skb->data[1] == 0x03)) skb_pull(skb, 2); @@ -708,6 +713,10 @@ discard: return 0; error: + /* Put UDP header back */ + __skb_push(skb, sizeof(struct udphdr)); + +no_tunnel: return 1; } @@ -1049,6 +1058,8 @@ static int pppol2tp_xmit(struct ppp_chan /* Get routing info from the tunnel socket */ dst_release(skb->dst); skb->dst = sk_dst_get(sk_tun); + skb_orphan(skb); + skb->sk = sk_tun; /* Queue the packet to IP for output */ len = skb->len; -- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/