net: sched: act_ctinfo: fix memory leak

BugLink: https://bugs.launchpad.net/bugs/1862429
[ 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>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

diff --git a/net/sched/act_ctinfo.c b/net/sched/act_ctinfo.c
index 0dbcfd1dca7bf354a51892adeed5a5fc3b4889fd..f45995a6237a6fcb95ba90553b16939c20c1902c 100644 (file)
--- a/net/sched/act_ctinfo.c
+++ b/net/sched/act_ctinfo.c
@@ -360,6 +360,16 @@ static int tcf_ctinfo_search(struct net *net, struct tc_action **a, u32 index)
        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_ops = {
        .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),