[PATCH net] ipv6: addrlabel: fix possible memory leak in ip6addrlbl_net_init

From: Wang Hai
Date: Sat Nov 21 2020 - 21:32:42 EST


kmemleak report a memory leak as follows:

unreferenced object 0xffff8880059c6a00 (size 64):
comm "ip", pid 23696, jiffies 4296590183 (age 1755.384s)
hex dump (first 32 bytes):
20 01 00 10 00 00 00 00 00 00 00 00 00 00 00 00 ...............
1c 00 00 00 00 00 00 00 00 00 00 00 07 00 00 00 ................
backtrace:
[<00000000aa4e7a87>] ip6addrlbl_add+0x90/0xbb0
[<0000000070b8d7f1>] ip6addrlbl_net_init+0x109/0x170
[<000000006a9ca9d4>] ops_init+0xa8/0x3c0
[<000000002da57bf2>] setup_net+0x2de/0x7e0
[<000000004e52d573>] copy_net_ns+0x27d/0x530
[<00000000b07ae2b4>] create_new_namespaces+0x382/0xa30
[<000000003b76d36f>] unshare_nsproxy_namespaces+0xa1/0x1d0
[<0000000030653721>] ksys_unshare+0x3a4/0x780
[<0000000007e82e40>] __x64_sys_unshare+0x2d/0x40
[<0000000031a10c08>] do_syscall_64+0x33/0x40
[<0000000099df30e7>] entry_SYSCALL_64_after_hwframe+0x44/0xa9

We should free all rules when we catch an error in ip6addrlbl_net_init().
otherwise a memory leak will occur.

Fixes: 2a8cc6c89039 ("[IPV6] ADDRCONF: Support RFC3484 configurable address selection policy table.")
Reported-by: Hulk Robot <hulkci@xxxxxxxxxx>
Signed-off-by: Wang Hai <wanghai38@xxxxxxxxxx>
---
net/ipv6/addrlabel.c | 14 ++++++++++++--
1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/net/ipv6/addrlabel.c b/net/ipv6/addrlabel.c
index 642fc6ac13d2..637e323a0224 100644
--- a/net/ipv6/addrlabel.c
+++ b/net/ipv6/addrlabel.c
@@ -306,6 +306,8 @@ static int ip6addrlbl_del(struct net *net,
/* add default label */
static int __net_init ip6addrlbl_net_init(struct net *net)
{
+ struct ip6addrlbl_entry *p = NULL;
+ struct hlist_node *n;
int err = 0;
int i;

@@ -320,9 +322,17 @@ static int __net_init ip6addrlbl_net_init(struct net *net)
ip6addrlbl_init_table[i].prefixlen,
0,
ip6addrlbl_init_table[i].label, 0);
- /* XXX: should we free all rules when we catch an error? */
- if (ret && (!err || err != -ENOMEM))
+ if (ret && (!err || err != -ENOMEM)) {
err = ret;
+ goto err_ip6addrlbl_add;
+ }
+ }
+ return err;
+
+err_ip6addrlbl_add:
+ hlist_for_each_entry_safe(p, n, &net->ipv6.ip6addrlbl_table.head, list) {
+ hlist_del_rcu(&p->list);
+ kfree_rcu(p, rcu);
}
return err;
}
--
2.17.1