net/sched: fix idr leak on the error path of tcf_bpf_init()

when the following command sequence is entered

 # tc action add action bpf bytecode '4,40 0 0 12,31 0 1 2048,6 0 0 262144,6 0 0 0' index 100
 RTNETLINK answers: Invalid argument
 We have an error talking to the kernel
 # tc action add action bpf bytecode '4,40 0 0 12,21 0 1 2048,6 0 0 262144,6 0 0 0' index 100
 RTNETLINK answers: No space left on device
 We have an error talking to the kernel

act_bpf correctly refuses to install the first TC rule, because 31 is not
a valid instruction. However, it refuses to install the second TC rule,
even if the BPF code is correct. Furthermore, it's no more possible to
install any other rule having the same value of 'index' until act_bpf
module is unloaded/inserted again. After the idr has been reserved, call
tcf_idr_release() instead of tcf_idr_cleanup(), to fix this issue.

Fixes: 65a206c ("net/sched: Change act_api and act_xxx modules to use IDR")
Acked-by: Jamal Hadi Salim <[email protected]>
Signed-off-by: Davide Caratti <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

Author: dcaratti

net/sched/act_bpf.c

@@ -352,7 +352,7 @@ static int tcf_bpf_init(struct net *net, struct nlattr *nla,
 	return res;
 out:
 	if (res == ACT_P_CREATED)
-		tcf_idr_cleanup(*act, est);
+		tcf_idr_release(*act, bind);
 
 	return ret;
 }