net/sched: fix memory leak in act_tunnel_key_init()

net/sched: fix memory leak in act_tunnel_key_init()

If users try to install act_tunnel_key 'set' rules with duplicate values
of 'index', the tunnel metadata are allocated, but never released. Then,
kmemleak complains as follows:

 # tc a a a tunnel_key set src_ip 1.1.1.1 dst_ip 2.2.2.2 id 42 index 111
 # echo clear > /sys/kernel/debug/kmemleak
 # tc a a a tunnel_key set src_ip 1.1.1.1 dst_ip 2.2.2.2 id 42 index 111
 Error: TC IDR already exists.
 We have an error talking to the kernel
 # echo scan > /sys/kernel/debug/kmemleak
 # cat /sys/kernel/debug/kmemleak
 unreferenced object 0xffff8800574e6c80 (size 256):
   comm "tc", pid 5617, jiffies 4298118009 (age 57.990s)
   hex dump (first 32 bytes):
     00 00 00 00 00 00 00 00 00 1c e8 b0 ff ff ff ff  ................
     81 24 c2 ad ff ff ff ff 00 00 00 00 00 00 00 00  .$..............
   backtrace:
     [<00000000b7afbf4e>] tunnel_key_init+0x8a5/0x1800 [act_tunnel_key]
     [<000000007d98fccd>] tcf_action_init_1+0x698/0xac0
     [<0000000099b8f7cc>] tcf_action_init+0x15c/0x590
     [<00000000dc60eebe>] tc_ctl_action+0x336/0x5c2
     [<000000002f5a2f7d>] rtnetlink_rcv_msg+0x357/0x8e0
     [<000000000bfe7575>] netlink_rcv_skb+0x124/0x350
     [<00000000edab656f>] netlink_unicast+0x40f/0x5d0
     [<00000000b322cdcb>] netlink_sendmsg+0x6e8/0xba0
     [<0000000063d9d490>] sock_sendmsg+0xb3/0xf0
     [<00000000f0d3315a>] ___sys_sendmsg+0x654/0x960
     [<00000000c06cbd42>] __sys_sendmsg+0xd3/0x170
     [<00000000ce72e4b0>] do_syscall_64+0xa5/0x470
     [<000000005caa2d97>] entry_SYSCALL_64_after_hwframe+0x49/0xbe
     [<00000000fac1b476>] 0xffffffffffffffff

This problem theoretically happens also in case users attempt to setup a
geneve rule having wrong configuration data, or when the kernel fails to
allocate 'params_new'. Ensure that tunnel_key_init() releases the tunnel
metadata also in the above conditions.

Addresses-Coverity-ID: 1373974 ("Resource leak")
Fixes: 2a0a25bb7e939 ("net/sched: Introduce act_tunnel_key")
Fixes: fa0e9dd4f9a7c ("net/sched: add tunnel option support to act_tunnel_key")
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>