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authorDaniel Borkmann <daniel@iogearbox.net>2015-07-17 23:38:45 +0300
committerDavid S. Miller <davem@davemloft.net>2015-07-21 10:25:03 +0300
commit32b2f4b196b37695fdb42b31afcbc15399d6ef91 (patch)
treedb51c8acd5f1049be5ceea4d9bc5f0b889e460ec /net/sched/cls_flow.c
parentff3532f2655b79058fec035ca54fced69a483084 (diff)
downloadlinux-32b2f4b196b37695fdb42b31afcbc15399d6ef91.tar.xz
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 <daniel@iogearbox.net> Acked-by: John Fastabend <john.r.fastabend@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/sched/cls_flow.c')
-rw-r--r--net/sched/cls_flow.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/net/sched/cls_flow.c b/net/sched/cls_flow.c
index 76bc3a20ffdb..bb2a0f529c1f 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;