From 8a533666d1591cf4ea596c6bd710e2fe682cb56a Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Thu, 9 Feb 2012 16:13:19 -0500 Subject: net: fix NULL dereferences in check_peer_redir() [ Upstream commit d3aaeb38c40e5a6c08dd31a1b64da65c4352be36, along with dependent backports of commits: 69cce1d1404968f78b177a0314f5822d5afdbbfb 9de79c127cccecb11ae6a21ab1499e87aa222880 218fa90f072e4aeff9003d57e390857f4f35513e 580da35a31f91a594f3090b7a2c39b85cb051a12 f7e57044eeb1841847c24aa06766c8290c202583 e049f28883126c689cf95859480d9ee4ab23b7fa ] Gergely Kalman reported crashes in check_peer_redir(). It appears commit f39925dbde778 (ipv4: Cache learned redirect information in inetpeer.) added a race, leading to possible NULL ptr dereference. Since we can now change dst neighbour, we should make sure a reader can safely use a neighbour. Add RCU protection to dst neighbour, and make sure check_peer_redir() can be called safely by different cpus in parallel. As neighbours are already freed after one RCU grace period, this patch should not add typical RCU penalty (cache cold effects) Many thanks to Gergely for providing a pretty report pointing to the bug. Reported-by: Gergely Kalman Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- drivers/scsi/cxgbi/cxgb3i/cxgb3i.c | 2 +- drivers/scsi/cxgbi/cxgb4i/cxgb4i.c | 2 +- drivers/scsi/cxgbi/libcxgbi.c | 4 ++-- 3 files changed, 4 insertions(+), 4 deletions(-) (limited to 'drivers/scsi') diff --git a/drivers/scsi/cxgbi/cxgb3i/cxgb3i.c b/drivers/scsi/cxgbi/cxgb3i/cxgb3i.c index b2d6611..143f268 100644 --- a/drivers/scsi/cxgbi/cxgb3i/cxgb3i.c +++ b/drivers/scsi/cxgbi/cxgb3i/cxgb3i.c @@ -985,7 +985,7 @@ static int init_act_open(struct cxgbi_sock *csk) csk->saddr.sin_addr.s_addr = chba->ipv4addr; csk->rss_qid = 0; - csk->l2t = t3_l2t_get(t3dev, dst->neighbour, ndev); + csk->l2t = t3_l2t_get(t3dev, dst_get_neighbour(dst), ndev); if (!csk->l2t) { pr_err("NO l2t available.\n"); return -EINVAL; diff --git a/drivers/scsi/cxgbi/cxgb4i/cxgb4i.c b/drivers/scsi/cxgbi/cxgb4i/cxgb4i.c index f3a4cd7..ae13c49 100644 --- a/drivers/scsi/cxgbi/cxgb4i/cxgb4i.c +++ b/drivers/scsi/cxgbi/cxgb4i/cxgb4i.c @@ -1160,7 +1160,7 @@ static int init_act_open(struct cxgbi_sock *csk) cxgbi_sock_set_flag(csk, CTPF_HAS_ATID); cxgbi_sock_get(csk); - csk->l2t = cxgb4_l2t_get(lldi->l2t, csk->dst->neighbour, ndev, 0); + csk->l2t = cxgb4_l2t_get(lldi->l2t, dst_get_neighbour(csk->dst), ndev, 0); if (!csk->l2t) { pr_err("%s, cannot alloc l2t.\n", ndev->name); goto rel_resource; diff --git a/drivers/scsi/cxgbi/libcxgbi.c b/drivers/scsi/cxgbi/libcxgbi.c index a2a9c7c..77ac217 100644 --- a/drivers/scsi/cxgbi/libcxgbi.c +++ b/drivers/scsi/cxgbi/libcxgbi.c @@ -492,7 +492,7 @@ static struct cxgbi_sock *cxgbi_check_route(struct sockaddr *dst_addr) goto err_out; } dst = &rt->dst; - ndev = dst->neighbour->dev; + ndev = dst_get_neighbour(dst)->dev; if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) { pr_info("multi-cast route %pI4, port %u, dev %s.\n", @@ -506,7 +506,7 @@ static struct cxgbi_sock *cxgbi_check_route(struct sockaddr *dst_addr) ndev = ip_dev_find(&init_net, daddr->sin_addr.s_addr); mtu = ndev->mtu; pr_info("rt dev %s, loopback -> %s, mtu %u.\n", - dst->neighbour->dev->name, ndev->name, mtu); + dst_get_neighbour(dst)->dev->name, ndev->name, mtu); } cdev = cxgbi_device_find_by_netdev(ndev, &port); -- cgit v1.1