From f6bfc46da6292b630ba389592123f0dd02066172 Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Fri, 17 Jul 2015 22:38:43 +0200 Subject: [PATCH 1/3] sched: cls_bpf: fix panic on filter replace The following test case causes a NULL pointer dereference in cls_bpf: FOO="1,6 0 0 4294967295," tc filter add dev foo parent 1: bpf bytecode "$FOO" flowid 1:1 action ok tc filter replace dev foo parent 1: pref 49152 handle 0x1 \ bpf bytecode "$FOO" flowid 1:1 action drop The problem is that commit 1f947bf151e9 ("net: sched: rcu'ify cls_bpf") accidentally swapped the arguments of list_replace_rcu(), the old element needs to be the first argument and the new element the second. Fixes: 1f947bf151e9 ("net: sched: rcu'ify cls_bpf") Signed-off-by: Daniel Borkmann Acked-by: John Fastabend Acked-by: Alexei Starovoitov Signed-off-by: David S. Miller --- net/sched/cls_bpf.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/sched/cls_bpf.c b/net/sched/cls_bpf.c index c79ecfd36e0f02..e5168f8b964096 100644 --- a/net/sched/cls_bpf.c +++ b/net/sched/cls_bpf.c @@ -378,7 +378,7 @@ static int cls_bpf_change(struct net *net, struct sk_buff *in_skb, goto errout; if (oldprog) { - list_replace_rcu(&prog->link, &oldprog->link); + list_replace_rcu(&oldprog->link, &prog->link); tcf_unbind_filter(tp, &oldprog->res); call_rcu(&oldprog->rcu, __cls_bpf_delete_prog); } else { From ff3532f2655b79058fec035ca54fced69a483084 Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Fri, 17 Jul 2015 22:38:44 +0200 Subject: [PATCH 2/3] sched: cls_flower: fix panic on filter replace The following test case causes a NULL pointer dereference in cls_flower: tc filter add dev foo parent 1: flower eth_type ipv4 action ok flowid 1:1 tc filter replace dev foo parent 1: pref 49152 handle 0x1 \ flower eth_type ipv6 action ok flowid 1:1 The problem is that commit 77b9900ef53a ("tc: introduce Flower classifier") accidentally swapped the arguments of list_replace_rcu(), the old element needs to be the first argument and the new element the second. Fixes: 77b9900ef53a ("tc: introduce Flower classifier") Signed-off-by: Daniel Borkmann Acked-by: Jiri Pirko Signed-off-by: David S. Miller --- net/sched/cls_flower.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/sched/cls_flower.c b/net/sched/cls_flower.c index 9d37ccd95062a6..2f3d03f99487ed 100644 --- a/net/sched/cls_flower.c +++ b/net/sched/cls_flower.c @@ -499,7 +499,7 @@ static int fl_change(struct net *net, struct sk_buff *in_skb, *arg = (unsigned long) fnew; if (fold) { - list_replace_rcu(&fnew->list, &fold->list); + list_replace_rcu(&fold->list, &fnew->list); tcf_unbind_filter(tp, &fold->res); call_rcu(&fold->rcu, fl_destroy_filter); } else { From 32b2f4b196b37695fdb42b31afcbc15399d6ef91 Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Fri, 17 Jul 2015 22:38:45 +0200 Subject: [PATCH 3/3] sched: cls_flow: fix panic on filter replace The following test case causes a NULL pointer dereference in cls_flow: tc filter add dev foo parent 1: handle 0x1 flow hash keys dst action ok tc filter replace dev foo parent 1: pref 49152 handle 0x1 \ flow hash keys mark action drop To be more precise, actually two different panics are fixed, the first occurs because tcf_exts_init() is not called on the newly allocated filter when we do a replace. And the second panic uncovered after that happens since the arguments of list_replace_rcu() are swapped, the old element needs to be the first argument and the new element the second. Fixes: 70da9f0bf999 ("net: sched: cls_flow use RCU") Signed-off-by: Daniel Borkmann Acked-by: John Fastabend Signed-off-by: David S. Miller --- net/sched/cls_flow.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/net/sched/cls_flow.c b/net/sched/cls_flow.c index 76bc3a20ffdb31..bb2a0f529c1f51 100644 --- a/net/sched/cls_flow.c +++ b/net/sched/cls_flow.c @@ -425,6 +425,8 @@ static int flow_change(struct net *net, struct sk_buff *in_skb, if (!fnew) goto err2; + tcf_exts_init(&fnew->exts, TCA_FLOW_ACT, TCA_FLOW_POLICE); + fold = (struct flow_filter *)*arg; if (fold) { err = -EINVAL; @@ -486,7 +488,6 @@ static int flow_change(struct net *net, struct sk_buff *in_skb, fnew->mask = ~0U; fnew->tp = tp; get_random_bytes(&fnew->hashrnd, 4); - tcf_exts_init(&fnew->exts, TCA_FLOW_ACT, TCA_FLOW_POLICE); } fnew->perturb_timer.function = flow_perturbation; @@ -526,7 +527,7 @@ static int flow_change(struct net *net, struct sk_buff *in_skb, if (*arg == 0) list_add_tail_rcu(&fnew->list, &head->filters); else - list_replace_rcu(&fnew->list, &fold->list); + list_replace_rcu(&fold->list, &fnew->list); *arg = (unsigned long)fnew;