net_sched: fix an OOB access in cls_tcindex

Browse source

As Eric noticed, tcindex_alloc_perfect_hash() uses cp->hash
to compute the size of memory allocation, but cp->hash is
set again after the allocation, this caused an out-of-bound
access.

So we have to move all cp->hash initialization and computation
before the memory allocation. Move cp->mask and cp->shift together
as cp->hash may need them for computation too.

Reported-and-tested-by: syzbot+35d4dea36c387813ed31@syzkaller.appspotmail.com
Fixes: 331b72922c ("net: sched: RCU cls_tcindex")
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: Jiri Pirko <jiri@resnulli.us>
Cc: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

...

This commit is contained in:

Cong Wang 2020-02-02 21:14:35 -08:00 • committed by David S. Miller

parent 83b4304530

commit 599be01ee5

1 changed files with 20 additions and 20 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

40

net/sched/cls_tcindex.c

View file