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>

diff --git a/net/sched/cls_tcindex.c b/net/sched/cls_tcindex.c
index 3e1695b66e3157f06dec4b4d66fe47646e3175de..ab66e2b38e66243941f206bf0797d233047a63c9 100644 (file)
--- a/net/sched/cls_tcindex.c
+++ b/net/sched/cls_tcindex.c
@@ -325,6 +325,7 @@ tcindex_set_parms(struct net *net, struct tcf_proto *tp, unsigned long base,
 
                if (tcindex_alloc_perfect_hash(cp) < 0)
                        goto errout;
+               cp->alloc_hash = cp->hash;
                for (i = 0; i < min(cp->hash, p->hash); i++)
                        cp->perfect[i].res = p->perfect[i].res;
                balloc = 1;