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| author | Cong Wang <xiyou.wangcong@gmail.com> | 2017-10-28 08:08:56 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-11-18 13:30:39 +0300 |
| commit | 912a2fe3b2e70b110e25566e53b4d79caf10d8f3 (patch) | |
| tree | dfdbaf71c9192b4b9f3658fe8f7d1ccca669eae4 | |
| parent | a796901e58ee4d6fc5e0f4c87845bf4b6c353680 (diff) | |
| download | linux-912a2fe3b2e70b110e25566e53b4d79caf10d8f3.tar.xz | |
net_sched: avoid matching qdisc with zero handle
[ Upstream commit 50317fce2cc70a2bbbc4b42c31bbad510382a53c ]
Davide found the following script triggers a NULL pointer
dereference:
ip l a name eth0 type dummy
tc q a dev eth0 parent :1 handle 1: htb
This is because for a freshly created netdevice noop_qdisc
is attached and when passing 'parent :1', kernel actually
tries to match the major handle which is 0 and noop_qdisc
has handle 0 so is matched by mistake. Commit 69012ae425d7
tries to fix a similar bug but still misses this case.
Handle 0 is not a valid one, should be just skipped. In
fact, kernel uses it as TC_H_UNSPEC.
Fixes: 69012ae425d7 ("net: sched: fix handling of singleton qdiscs with qdisc_hash")
Fixes: 59cc1f61f09c ("net: sched:convert qdisc linked list to hashtable")
Reported-by: Davide Caratti <dcaratti@redhat.com>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | net/sched/sch_api.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c index 4fb5a3222d0d..7935db0d787c 100644 --- a/net/sched/sch_api.c +++ b/net/sched/sch_api.c @@ -307,6 +307,8 @@ struct Qdisc *qdisc_lookup(struct net_device *dev, u32 handle) { struct Qdisc *q; + if (!handle) + return NULL; q = qdisc_match_from_root(dev->qdisc, handle); if (q) goto out; |