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net/sched: fix idr leak in the error path of __tcf_ipt_init()

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__tcf_ipt_init() can fail after the idr has been successfully reserved.
When this happens, subsequent attempts to configure xt/ipt rules using
the same idr value systematically fail with -ENOSPC:

 # tc action add action xt -j LOG --log-prefix test1 index 100
 tablename: mangle hook: NF_IP_POST_ROUTING
         target:  LOG level warning prefix "test1" index 100
 RTNETLINK answers: Cannot allocate memory
 We have an error talking to the kernel
 Command "(null)" is unknown, try "tc actions help".
 # tc action add action xt -j LOG --log-prefix test1 index 100
 tablename: mangle hook: NF_IP_POST_ROUTING
         target:  LOG level warning prefix "test1" index 100
 RTNETLINK answers: No space left on device
 We have an error talking to the kernel
 Command "(null)" is unknown, try "tc actions help".
 # tc action add action xt -j LOG --log-prefix test1 index 100
 tablename: mangle hook: NF_IP_POST_ROUTING
         target:  LOG level warning prefix "test1" index 100
 RTNETLINK answers: No space left on device
 We have an error talking to the kernel
 ...

Fix this in the error path of __tcf_ipt_init(), calling tcf_idr_release()
in place of tcf_idr_cleanup(). Since tcf_ipt_release() can now be called
when tcfi_t is NULL, we also need to protect calls to ipt_destroy_target()
to avoid NULL pointer dereference.

Fixes: 65a206c01e ("net/sched: Change act_api and act_xxx modules to use IDR")
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Davide Caratti 2018-03-19 15:31:26 +01:00 committed by David S. Miller
parent 94fa3f929e
commit 1e46ef1762
1 changed files with 6 additions and 3 deletions
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9
net/sched/act_ipt.c
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@ -80,9 +80,12 @@ static void ipt_destroy_target(struct xt_entry_target *t)
static void tcf_ipt_release(struct tc_action *a)
{
struct tcf_ipt *ipt = to_ipt(a);
ipt_destroy_target(ipt->tcfi_t);
if (ipt->tcfi_t) {
ipt_destroy_target(ipt->tcfi_t);
kfree(ipt->tcfi_t);
}
kfree(ipt->tcfi_tname);
kfree(ipt->tcfi_t);
}
static const struct nla_policy ipt_policy[TCA_IPT_MAX + 1] = {
@ -187,7 +190,7 @@ static int __tcf_ipt_init(struct net *net, unsigned int id, struct nlattr *nla,
kfree(tname);
err1:
if (ret == ACT_P_CREATED)
tcf_idr_cleanup(*a, est);
tcf_idr_release(*a, bind);
return err;
}