cls_flower: call nla_ok() before nla_next()
authorCong Wang <cong.wang@bytedance.com>
Fri, 15 Jan 2021 18:50:24 +0000 (10:50 -0800)
committerJakub Kicinski <kuba@kernel.org>
Fri, 15 Jan 2021 23:48:53 +0000 (15:48 -0800)
commitc96adff95619178e2118925578343ad54857c80c
tree33cee1a4b529d142551ac9a95ef517c3882df21f
parentb7ba6cfabc42fc846eb96e33f1edcd3ea6290a27
cls_flower: call nla_ok() before nla_next()

fl_set_enc_opt() simply checks if there are still bytes left to parse,
but this is not sufficent as syzbot seems to be able to generate
malformatted netlink messages. nla_ok() is more strict so should be
used to validate the next nlattr here.

And nla_validate_nested_deprecated() has less strict check too, it is
probably too late to switch to the strict version, but we can just
call nla_ok() too after it.

Reported-and-tested-by: syzbot+2624e3778b18fc497c92@syzkaller.appspotmail.com
Fixes: 0a6e77784f49 ("net/sched: allow flower to match tunnel options")
Fixes: 79b1011cb33d ("net: sched: allow flower to match erspan options")
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: Xin Long <lucien.xin@gmail.com>
Cc: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: Cong Wang <cong.wang@bytedance.com>
Link: https://lore.kernel.org/r/20210115185024.72298-1-xiyou.wangcong@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
net/sched/cls_flower.c