Return-Path: From: Glenn Ruben Bakke To: CC: , , Subject: [PATCH stable backport] Bluetooth: 6lowpan: Fix memory corruption of ipv6 destination address Date: Tue, 31 May 2016 12:23:15 +0200 Message-ID: <1464690195-2575-1-git-send-email-glenn.ruben.bakke@nordicsemi.no> MIME-Version: 1.0 Content-Type: text/plain List-ID: Backport for v4.5 and v4.6 of commit 55441070ca1cbd47ce1ad2959bbf4b47aed9b83b upstream. The memcpy of ipv6 header destination address to the skb control block (sbk->cb) in header_create() results in currupted memory when bt_xmit() is issued. The skb->cb is "released" in the return of header_create() making room for lower layer to minipulate the skb->cb. The value retrieved in bt_xmit is not persistent across header creation and sending, and the lower layer will overwrite portions of skb->cb, making the copied destination address wrong. The memory corruption will lead to non-working multicast as the first 4 bytes of the copied destination address is replaced by a value that resolves into a non-multicast prefix. This fix removes the dependency on the skb control block between header creation and send, by moving the destination address memcpy to the send function path (setup_create, which is called from bt_xmit). Signed-off-by: Glenn Ruben Bakke --- net/bluetooth/6lowpan.c | 11 ++++------- 1 file changed, 4 insertions(+), 7 deletions(-) diff --git a/net/bluetooth/6lowpan.c b/net/bluetooth/6lowpan.c index 8a4cc2f..e45cb91 100644 --- a/net/bluetooth/6lowpan.c +++ b/net/bluetooth/6lowpan.c @@ -431,15 +431,18 @@ static int setup_header(struct sk_buff *skb, struct net_device *netdev, bdaddr_t *peer_addr, u8 *peer_addr_type) { struct in6_addr ipv6_daddr; + struct ipv6hdr *hdr; struct lowpan_dev *dev; struct lowpan_peer *peer; bdaddr_t addr, *any = BDADDR_ANY; u8 *daddr = any->b; int err, status = 0; + hdr = ipv6_hdr(skb); + dev = lowpan_dev(netdev); - memcpy(&ipv6_daddr, &lowpan_cb(skb)->addr, sizeof(ipv6_daddr)); + memcpy(&ipv6_daddr, &hdr->daddr, sizeof(ipv6_daddr)); if (ipv6_addr_is_multicast(&ipv6_daddr)) { lowpan_cb(skb)->chan = NULL; @@ -489,15 +492,9 @@ static int header_create(struct sk_buff *skb, struct net_device *netdev, unsigned short type, const void *_daddr, const void *_saddr, unsigned int len) { - struct ipv6hdr *hdr; - if (type != ETH_P_IPV6) return -EINVAL; - hdr = ipv6_hdr(skb); - - memcpy(&lowpan_cb(skb)->addr, &hdr->daddr, sizeof(struct in6_addr)); - return 0; } -- 2.5.0