Commit d6cdc5bb authored Mar 11, 2020 by Cong Wang Committed by Greg Kroah-Hartman Apr 02, 2020

net_sched: keep alloc_hash updated after hash allocation



[ Upstream commit 0d1c3530e1bd38382edef72591b78e877e0edcd3 ]

In commit 599be01ee567 ("net_sched: fix an OOB access in cls_tcindex")
I moved cp->hash calculation before the first
tcindex_alloc_perfect_hash(), but cp->alloc_hash is left untouched.
This difference could lead to another out of bound access.

cp->alloc_hash should always be the size allocated, we should
update it after this tcindex_alloc_perfect_hash().

Reported-and-tested-by:  <syzbot+dcc34d54d68ef7d2d53d@syzkaller.appspotmail.com>
Reported-and-tested-by:  <syzbot+c72da7b9ed57cde6fca2@syzkaller.appspotmail.com>
Fixes: 599be01ee567 ("net_sched: fix an OOB access in cls_tcindex")
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: Jiri Pirko <jiri@resnulli.us>
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>

parent 7518af64

net/sched/cls_tcindex.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -293,6 +293,7 @@ tcindex_set_parms(struct net net, struct tcf_proto tp, unsigned long base,
		sizeof(r) cp->hash, GFP_KERNEL);
		if (!cp->perfect)
		goto errout;
		cp->alloc_hash = cp->hash;
		for (i = 0; i < min(cp->hash, p->hash); i++)
		tcf_exts_init(&cp->perfect[i].exts,
		TCA_TCINDEX_ACT, TCA_TCINDEX_POLICE);