net: ipv4: Fix memory leak in network namespace dismantle
[ Upstream commit f97f4dd8b3bb9d0993d2491e0f22024c68109184 ]
IPv4 routing tables are flushed in two cases:
1. In response to events in the netdev and inetaddr notification chains
2. When a network namespace is being dismantled
In both cases only routes associated with a dead nexthop group are
flushed. However, a nexthop group will only be marked as dead in case it
is populated with actual nexthops using a nexthop device. This is not
the case when the route in question is an error route (e.g.,
'blackhole', 'unreachable').
Therefore, when a network namespace is being dismantled such routes are
not flushed and leaked [1].
To reproduce:
# ip netns add blue
# ip -n blue route add unreachable 192.0.2.0/24
# ip netns del blue
Fix this by not skipping error routes that are not marked with
RTNH_F_DEAD when flushing the routing tables.
To prevent the flushing of such routes in case #1, add a parameter to
fib_table_flush() that indicates if the table is flushed as part of
namespace dismantle or not.
Note that this problem does not exist in IPv6 since error routes are
associated with the loopback device.
[1]
unreferenced object 0xffff888066650338 (size 56):
comm "ip", pid 1206, jiffies 4294786063 (age 26.235s)
hex dump (first 32 bytes):
00 00 00 00 00 00 00 00 b0 1c 62 61 80 88 ff ff ..........ba....
e8 8b a1 64 80 88 ff ff 00 07 00 08 fe 00 00 00 ...d............
backtrace:
[<00000000856ed27d>] inet_rtm_newroute+0x129/0x220
[<00000000fcdfc00a>] rtnetlink_rcv_msg+0x397/0xa20
[<00000000cb85801a>] netlink_rcv_skb+0x132/0x380
[<00000000ebc991d2>] netlink_unicast+0x4c0/0x690
[<0000000014f62875>] netlink_sendmsg+0x929/0xe10
[<00000000bac9d967>] sock_sendmsg+0xc8/0x110
[<00000000223e6485>] ___sys_sendmsg+0x77a/0x8f0
[<000000002e94f880>] __sys_sendmsg+0xf7/0x250
[<00000000ccb1fa72>] do_syscall_64+0x14d/0x610
[<00000000ffbe3dae>] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[<000000003a8b605b>] 0xffffffffffffffff
unreferenced object 0xffff888061621c88 (size 48):
comm "ip", pid 1206, jiffies 4294786063 (age 26.235s)
hex dump (first 32 bytes):
6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk
6b 6b 6b 6b 6b 6b 6b 6b d8 8e 26 5f 80 88 ff ff kkkkkkkk..&_....
backtrace:
[<00000000733609e3>] fib_table_insert+0x978/0x1500
[<00000000856ed27d>] inet_rtm_newroute+0x129/0x220
[<00000000fcdfc00a>] rtnetlink_rcv_msg+0x397/0xa20
[<00000000cb85801a>] netlink_rcv_skb+0x132/0x380
[<00000000ebc991d2>] netlink_unicast+0x4c0/0x690
[<0000000014f62875>] netlink_sendmsg+0x929/0xe10
[<00000000bac9d967>] sock_sendmsg+0xc8/0x110
[<00000000223e6485>] ___sys_sendmsg+0x77a/0x8f0
[<000000002e94f880>] __sys_sendmsg+0xf7/0x250
[<00000000ccb1fa72>] do_syscall_64+0x14d/0x610
[<00000000ffbe3dae>] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[<000000003a8b605b>] 0xffffffffffffffff
Fixes: 8cced9eff1d4 ("[NETNS]: Enable routing configuration in non-initial namespace.")
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Reviewed-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c
index 9364c39..cbe3fdb 100644
--- a/net/ipv4/fib_frontend.c
+++ b/net/ipv4/fib_frontend.c
@@ -193,7 +193,7 @@
struct fib_table *tb;
hlist_for_each_entry_safe(tb, tmp, head, tb_hlist)
- flushed += fib_table_flush(net, tb);
+ flushed += fib_table_flush(net, tb, false);
}
if (flushed)
@@ -1277,7 +1277,7 @@
hlist_for_each_entry_safe(tb, tmp, head, tb_hlist) {
hlist_del(&tb->tb_hlist);
- fib_table_flush(net, tb);
+ fib_table_flush(net, tb, true);
fib_free_table(tb);
}
}
diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c
index ef40bb6..36f0a8c 100644
--- a/net/ipv4/fib_trie.c
+++ b/net/ipv4/fib_trie.c
@@ -1826,7 +1826,7 @@
}
/* Caller must hold RTNL. */
-int fib_table_flush(struct net *net, struct fib_table *tb)
+int fib_table_flush(struct net *net, struct fib_table *tb, bool flush_all)
{
struct trie *t = (struct trie *)tb->tb_data;
struct key_vector *pn = t->kv;
@@ -1874,7 +1874,17 @@
hlist_for_each_entry_safe(fa, tmp, &n->leaf, fa_list) {
struct fib_info *fi = fa->fa_info;
- if (!fi || !(fi->fib_flags & RTNH_F_DEAD)) {
+ if (!fi ||
+ (!(fi->fib_flags & RTNH_F_DEAD) &&
+ !fib_props[fa->fa_type].error)) {
+ slen = fa->fa_slen;
+ continue;
+ }
+
+ /* Do not flush error routes if network namespace is
+ * not being dismantled
+ */
+ if (!flush_all && fib_props[fa->fa_type].error) {
slen = fa->fa_slen;
continue;
}