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| author | Davide Caratti <dcaratti@redhat.com> | 2017-09-16 14:02:21 +0200 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2017-09-18 16:37:36 -0700 |
| commit | 3ff4cbec87da48b0ec1f7b6196607b034de0c680 (patch) | |
| tree | cbddf4c0e857f8eb0077062bdfe235077c78abf9 /net | |
| parent | 8c22dab03ad072e45060c299c70d02a4f6fc4aab (diff) | |
| download | linux-3ff4cbec87da48b0ec1f7b6196607b034de0c680.tar.bz2 | |
net/sched: cls_matchall: fix crash when used with classful qdisc
this script, edited from Linux Advanced Routing and Traffic Control guide
tc q a dev en0 root handle 1: htb default a
tc c a dev en0 parent 1: classid 1:1 htb rate 6mbit burst 15k
tc c a dev en0 parent 1:1 classid 1:a htb rate 5mbit ceil 6mbit burst 15k
tc c a dev en0 parent 1:1 classid 1:b htb rate 1mbit ceil 6mbit burst 15k
tc f a dev en0 parent 1:0 prio 1 $clsname $clsargs classid 1:b
ping $address -c1
tc -s c s dev en0
classifies traffic to 1:b or 1:a, depending on whether the packet matches
or not the pattern $clsargs of filter $clsname. However, when $clsname is
'matchall', a systematic crash can be observed in htb_classify(). HTB and
classful qdiscs don't assign initial value to struct tcf_result, but then
they expect it to contain valid values after filters have been run. Thus,
current 'matchall' ignores the TCA_MATCHALL_CLASSID attribute, configured
by user, and makes HTB (and classful qdiscs) dereference random pointers.
By assigning head->res to *res in mall_classify(), before the actions are
invoked, we fix this crash and enable TCA_MATCHALL_CLASSID functionality,
that had no effect on 'matchall' classifier since its first introduction.
BugLink: https://bugzilla.redhat.com/show_bug.cgi?id=1460213
Reported-by: Jiri Benc <jbenc@redhat.com>
Fixes: b87f7936a932 ("net/sched: introduce Match-all classifier")
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Acked-by: Yotam Gigi <yotamg@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
| -rw-r--r-- | net/sched/cls_matchall.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/net/sched/cls_matchall.c b/net/sched/cls_matchall.c index 21cc45caf842..eeac606c95ab 100644 --- a/net/sched/cls_matchall.c +++ b/net/sched/cls_matchall.c @@ -32,6 +32,7 @@ static int mall_classify(struct sk_buff *skb, const struct tcf_proto *tp, if (tc_skip_sw(head->flags)) return -1; + *res = head->res; return tcf_exts_exec(skb, &head->exts, res); } |