From e65fcfd63a9a62baa5708484ff8edbe56eb3e7ec Mon Sep 17 00:00:00 2001 From: Paul Menage Date: Tue, 26 May 2009 20:47:02 -0700 Subject: cls_cgroup: read classid atomically in classifier Avoid reading the unsynchronized value cs->classid multiple times, since it could change concurrently from non-zero to zero; this would result in the classifier returning a positive result with a bogus (zero) classid. Signed-off-by: Paul Menage Reviewed-by: Li Zefan Signed-off-by: David S. Miller --- net/sched/cls_cgroup.c | 22 +++++++++++----------- 1 file changed, 11 insertions(+), 11 deletions(-) (limited to 'net/sched') diff --git a/net/sched/cls_cgroup.c b/net/sched/cls_cgroup.c index 91a3db4a76f8..cc29b44b1500 100644 --- a/net/sched/cls_cgroup.c +++ b/net/sched/cls_cgroup.c @@ -104,8 +104,7 @@ static int cls_cgroup_classify(struct sk_buff *skb, struct tcf_proto *tp, struct tcf_result *res) { struct cls_cgroup_head *head = tp->root; - struct cgroup_cls_state *cs; - int ret = 0; + u32 classid; /* * Due to the nature of the classifier it is required to ignore all @@ -121,17 +120,18 @@ static int cls_cgroup_classify(struct sk_buff *skb, struct tcf_proto *tp, return -1; rcu_read_lock(); - cs = task_cls_state(current); - if (cs->classid && tcf_em_tree_match(skb, &head->ematches, NULL)) { - res->classid = cs->classid; - res->class = 0; - ret = tcf_exts_exec(skb, &head->exts, res); - } else - ret = -1; - + classid = task_cls_state(current)->classid; rcu_read_unlock(); - return ret; + if (!classid) + return -1; + + if (!tcf_em_tree_match(skb, &head->ematches, NULL)) + return -1; + + res->classid = classid; + res->class = 0; + return tcf_exts_exec(skb, &head->exts, res); } static unsigned long cls_cgroup_get(struct tcf_proto *tp, u32 handle) -- cgit v1.2.3 From 12186be7d2e1106cede1cc728526e3d7998cbe94 Mon Sep 17 00:00:00 2001 From: Minoru Usui Date: Tue, 2 Jun 2009 02:17:34 -0700 Subject: net_cls: fix unconfigured struct tcf_proto keeps chaining and avoid kernel panic when we use cls_cgroup This patch fixes a bug which unconfigured struct tcf_proto keeps chaining in tc_ctl_tfilter(), and avoids kernel panic in cls_cgroup_classify() when we use cls_cgroup. When we execute 'tc filter add', tcf_proto is allocated, initialized by classifier's init(), and chained. After it's chained, tc_ctl_tfilter() calls classifier's change(). When classifier's change() fails, tc_ctl_tfilter() does not free and keeps tcf_proto. In addition, cls_cgroup is initialized in change() not in init(). It accesses unconfigured struct tcf_proto which is chained before change(), then hits Oops. Signed-off-by: Minoru Usui Signed-off-by: Jarek Poplawski Signed-off-by: Jamal Hadi Salim Tested-by: Minoru Usui Signed-off-by: David S. Miller --- net/sched/cls_api.c | 23 +++++++++++++++++------ 1 file changed, 17 insertions(+), 6 deletions(-) (limited to 'net/sched') diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c index 0759f32e9dca..09cdcdfe7e91 100644 --- a/net/sched/cls_api.c +++ b/net/sched/cls_api.c @@ -135,6 +135,7 @@ static int tc_ctl_tfilter(struct sk_buff *skb, struct nlmsghdr *n, void *arg) unsigned long cl; unsigned long fh; int err; + int tp_created = 0; if (net != &init_net) return -EINVAL; @@ -266,10 +267,7 @@ replay: goto errout; } - spin_lock_bh(root_lock); - tp->next = *back; - *back = tp; - spin_unlock_bh(root_lock); + tp_created = 1; } else if (tca[TCA_KIND] && nla_strcmp(tca[TCA_KIND], tp->ops->kind)) goto errout; @@ -296,8 +294,11 @@ replay: switch (n->nlmsg_type) { case RTM_NEWTFILTER: err = -EEXIST; - if (n->nlmsg_flags & NLM_F_EXCL) + if (n->nlmsg_flags & NLM_F_EXCL) { + if (tp_created) + tcf_destroy(tp); goto errout; + } break; case RTM_DELTFILTER: err = tp->ops->delete(tp, fh); @@ -314,8 +315,18 @@ replay: } err = tp->ops->change(tp, cl, t->tcm_handle, tca, &fh); - if (err == 0) + if (err == 0) { + if (tp_created) { + spin_lock_bh(root_lock); + tp->next = *back; + *back = tp; + spin_unlock_bh(root_lock); + } tfilter_notify(skb, n, tp, fh, RTM_NEWTFILTER); + } else { + if (tp_created) + tcf_destroy(tp); + } errout: if (cl) -- cgit v1.2.3