net/sched: act_police: fix memory leak in case of invalid control action

when users set an invalid control action, kmemleak complains as follows:

 # echo clear >/sys/kernel/debug/kmemleak
 # ./tdc.py -e b48b
 Test b48b: Add police action with exceed goto chain control action
 All test results:

 1..1
 ok 1 - b48b # Add police action with exceed goto chain control action
 about to flush the tap output if tests need to be skipped
 done flushing skipped test tap output
 # echo scan >/sys/kernel/debug/kmemleak
 # cat /sys/kernel/debug/kmemleak
 unreferenced object 0xffffa0fafbc3dde0 (size 96):
  comm "tc", pid 2358, jiffies 4294922738 (age 17.022s)
  hex dump (first 32 bytes):
    2a 00 00 20 00 00 00 00 00 00 7d 00 00 00 00 00  *.. ......}.....
    f8 07 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace:
    [<00000000648803d2>] tcf_action_init_1+0x384/0x4c0
    [<00000000cb69382e>] tcf_action_init+0x12b/0x1a0
    [<00000000847ef0d4>] tcf_action_add+0x73/0x170
    [<0000000093656e14>] tc_ctl_action+0x122/0x160
    [<0000000023c98e32>] rtnetlink_rcv_msg+0x263/0x2d0
    [<000000003493ae9c>] netlink_rcv_skb+0x4d/0x130
    [<00000000de63f8ba>] netlink_unicast+0x209/0x2d0
    [<00000000c3da0ebe>] netlink_sendmsg+0x2c1/0x3c0
    [<000000007a9e0753>] sock_sendmsg+0x33/0x40
    [<00000000457c6d2e>] ___sys_sendmsg+0x2a0/0x2f0
    [<00000000c5c6a086>] __sys_sendmsg+0x5e/0xa0
    [<00000000446eafce>] do_syscall_64+0x5b/0x180
    [<000000004aa871f2>] entry_SYSCALL_64_after_hwframe+0x44/0xa9
    [<00000000450c38ef>] 0xffffffffffffffff

change tcf_police_init() to avoid leaking 'new' in case TCA_POLICE_RESULT
contains TC_ACT_GOTO_CHAIN extended action.

Fixes: c08f5ed5d625 ("net/sched: act_police: disallow 'goto chain' on fallback control action")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Acked-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/sched/act_police.c b/net/sched/act_police.c
index 37c9b8f..ec8ec55 100644 (file)
--- a/net/sched/act_police.c
+++ b/net/sched/act_police.c
@@ -85,7 +85,7 @@ static int tcf_police_init(struct net *net, struct nlattr *nla,
                               int ovr, int bind, bool rtnl_held,
                               struct netlink_ext_ack *extack)
 {
-       int ret = 0, err;
+       int ret = 0, tcfp_result = TC_ACT_OK, err, size;
        struct nlattr *tb[TCA_POLICE_MAX + 1];
        struct tc_police *parm;
        struct tcf_police *police;
@@ -93,7 +93,6 @@ static int tcf_police_init(struct net *net, struct nlattr *nla,
        struct tc_action_net *tn = net_generic(net, police_net_id);
        struct tcf_police_params *new;
        bool exists = false;
-       int size;
 
        if (nla == NULL)
                return -EINVAL;
@@ -160,6 +159,16 @@ static int tcf_police_init(struct net *net, struct nlattr *nla,
                goto failure;
        }
 
+       if (tb[TCA_POLICE_RESULT]) {
+               tcfp_result = nla_get_u32(tb[TCA_POLICE_RESULT]);
+               if (TC_ACT_EXT_CMP(tcfp_result, TC_ACT_GOTO_CHAIN)) {
+                       NL_SET_ERR_MSG(extack,
+                                      "goto chain not allowed on fallback");
+                       err = -EINVAL;
+                       goto failure;
+               }
+       }
+
        new = kzalloc(sizeof(*new), GFP_KERNEL);
        if (unlikely(!new)) {
                err = -ENOMEM;
@@ -167,6 +176,7 @@ static int tcf_police_init(struct net *net, struct nlattr *nla,
        }
 
        /* No failure allowed after this point */
+       new->tcfp_result = tcfp_result;
        new->tcfp_mtu = parm->mtu;
        if (!new->tcfp_mtu) {
                new->tcfp_mtu = ~0;
@@ -196,16 +206,6 @@ static int tcf_police_init(struct net *net, struct nlattr *nla,
        if (tb[TCA_POLICE_AVRATE])
                new->tcfp_ewma_rate = nla_get_u32(tb[TCA_POLICE_AVRATE]);
 
-       if (tb[TCA_POLICE_RESULT]) {
-               new->tcfp_result = nla_get_u32(tb[TCA_POLICE_RESULT]);
-               if (TC_ACT_EXT_CMP(new->tcfp_result, TC_ACT_GOTO_CHAIN)) {
-                       NL_SET_ERR_MSG(extack,
-                                      "goto chain not allowed on fallback");
-                       err = -EINVAL;
-                       goto failure;
-               }
-       }
-
        spin_lock_bh(&police->tcf_lock);
        spin_lock_bh(&police->tcfp_lock);
        police->tcfp_t_c = ktime_get_ns();