[PATCH 5.4 156/222] net: sched: act_ctinfo: fix memory leak

Greg Kroah-Hartman
2020-01-22T13:26:48Z

From: Eric Dumazet <edumazet@google.com>

[ Upstream commit 09d4f10a5e78d76a53e3e584f1e6a701b6d24108 ]

Implement a cleanup method to properly free ci->params

BUG: memory leak
unreferenced object 0xffff88811746e2c0 (size 64):
comm "syz-executor617", pid 7106, jiffies 4294943055 (age 14.250s)
hex dump (first 32 bytes):
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
c0 34 60 84 ff ff ff ff 00 00 00 00 00 00 00 00 .4`.............
backtrace:
[<0000000015aa236f>] kmemleak_alloc_recursive include/linux/kmemleak.h:43 [inline]
[<0000000015aa236f>] slab_post_alloc_hook mm/slab.h:586 [inline]
[<0000000015aa236f>] slab_alloc mm/slab.c:3320 [inline]
[<0000000015aa236f>] kmem_cache_alloc_trace+0x145/0x2c0 mm/slab.c:3549
[<000000002c946bd1>] kmalloc include/linux/slab.h:556 [inline]
[<000000002c946bd1>] kzalloc include/linux/slab.h:670 [inline]
[<000000002c946bd1>] tcf_ctinfo_init+0x21a/0x530 net/sched/act_ctinfo.c:236
[<0000000086952cca>] tcf_action_init_1+0x400/0x5b0 net/sched/act_api.c:944
[<000000005ab29bf8>] tcf_action_init+0x135/0x1c0 net/sched/act_api.c:1000
[<00000000392f56f9>] tcf_action_add+0x9a/0x200 net/sched/act_api.c:1410
[<0000000088f3c5dd>] tc_ctl_action+0x14d/0x1bb net/sched/act_api.c:1465
[<000000006b39d986>] rtnetlink_rcv_msg+0x178/0x4b0 net/core/rtnetlink.c:5424
[<00000000fd6ecace>] netlink_rcv_skb+0x61/0x170 net/netlink/af_netlink.c:2477
[<0000000047493d02>] rtnetlink_rcv+0x1d/0x30 net/core/rtnetlink.c:5442
[<00000000bdcf8286>] netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline]
[<00000000bdcf8286>] netlink_unicast+0x223/0x310 net/netlink/af_netlink.c:1328
[<00000000fc5b92d9>] netlink_sendmsg+0x2c0/0x570 net/netlink/af_netlink.c:1917
[<00000000da84d076>] sock_sendmsg_nosec net/socket.c:639 [inline]
[<00000000da84d076>] sock_sendmsg+0x54/0x70 net/socket.c:659
[<0000000042fb2eee>] ____sys_sendmsg+0x2d0/0x300 net/socket.c:2330
[<000000008f23f67e>] ___sys_sendmsg+0x8a/0xd0 net/socket.c:2384
[<00000000d838e4f6>] __sys_sendmsg+0x80/0xf0 net/socket.c:2417
[<00000000289a9cb1>] __do_sys_sendmsg net/socket.c:2426 [inline]
[<00000000289a9cb1>] __se_sys_sendmsg net/socket.c:2424 [inline]
[<00000000289a9cb1>] __x64_sys_sendmsg+0x23/0x30 net/socket.c:2424

Fixes: 24ec483cec98 ("net: sched: Introduce act_ctinfo action")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Cc: Kevin 'ldir' Darbyshire-Bryant <ldir@darbyshire-bryant.me.uk>
Cc: Cong Wang <xiyou.wangcong@gmail.com>
Cc: Toke Høiland-Jørgensen <toke@redhat.com>
Acked-by: Kevin 'ldir' Darbyshire-Bryant <ldir@darbyshire-bryant.me.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/sched/act_ctinfo.c | 11 +++++++++++
1 file changed, 11 insertions(+)

--- a/net/sched/act_ctinfo.c
+++ b/net/sched/act_ctinfo.c
@@ -360,6 +360,16 @@ static int tcf_ctinfo_search(struct net
return tcf_idr_search(tn, a, index);
}

+static void tcf_ctinfo_cleanup(struct tc_action *a)
+{
+ struct tcf_ctinfo *ci = to_ctinfo(a);
+ struct tcf_ctinfo_params *cp;
+
+ cp = rcu_dereference_protected(ci->params, 1);
+ if (cp)
+ kfree_rcu(cp, rcu);
+}
+
static struct tc_action_ops act_ctinfo_ops = {
.kind = "ctinfo",
.id = TCA_ID_CTINFO,
@@ -367,6 +377,7 @@ static struct tc_action_ops act_ctinfo_o
.act = tcf_ctinfo_act,
.dump = tcf_ctinfo_dump,
.init = tcf_ctinfo_init,
+ .cleanup= tcf_ctinfo_cleanup,
.walk = tcf_ctinfo_walker,
.lookup = tcf_ctinfo_search,
.size = sizeof(struct tcf_ctinfo),