[PATCH 3.2 62/77] net: ipmr: fix static mfc/dev leaks on table destruction

[Ben Hutchings]

3.2.75-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Nikolay Aleksandrov <nikolay@xxxxxxxxxxxxxxxxxxx>

[ Upstream commit 0e615e9601a15efeeb8942cf7cd4dadba0c8c5a7 ]

When destroying an mrt table the static mfc entries and the static
devices are kept, which leads to devices that can never be destroyed
(because of refcnt taken) and leaked memory, for example:
unreferenced object 0xffff880034c144c0 (size 192):
  comm "mfc-broken", pid 4777, jiffies 4320349055 (age 46001.964s)
  hex dump (first 32 bytes):
    98 53 f0 34 00 88 ff ff 98 53 f0 34 00 88 ff ff  .S.4.....S.4....
    ef 0a 0a 14 01 02 03 04 00 00 00 00 01 00 00 00  ................
  backtrace:
    [<ffffffff815c1b9e>] kmemleak_alloc+0x4e/0xb0
    [<ffffffff811ea6e0>] kmem_cache_alloc+0x190/0x300
    [<ffffffff815931cb>] ip_mroute_setsockopt+0x5cb/0x910
    [<ffffffff8153d575>] do_ip_setsockopt.isra.11+0x105/0xff0
    [<ffffffff8153e490>] ip_setsockopt+0x30/0xa0
    [<ffffffff81564e13>] raw_setsockopt+0x33/0x90
    [<ffffffff814d1e14>] sock_common_setsockopt+0x14/0x20
    [<ffffffff814d0b51>] SyS_setsockopt+0x71/0xc0
    [<ffffffff815cdbf6>] entry_SYSCALL_64_fastpath+0x16/0x7a
    [<ffffffffffffffff>] 0xffffffffffffffff

Make sure that everything is cleaned on netns destruction.

Signed-off-by: Nikolay Aleksandrov <nikolay@xxxxxxxxxxxxxxxxxxx>
Reviewed-by: Cong Wang <cwang@xxxxxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
 net/ipv4/ipmr.c | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

--- a/net/ipv4/ipmr.c
+++ b/net/ipv4/ipmr.c
@@ -134,7 +134,7 @@ static int ipmr_cache_report(struct mr_t
 			     struct sk_buff *pkt, vifi_t vifi, int assert);
 static int __ipmr_fill_mroute(struct mr_table *mrt, struct sk_buff *skb,
 			      struct mfc_cache *c, struct rtmsg *rtm);
-static void mroute_clean_tables(struct mr_table *mrt);
+static void mroute_clean_tables(struct mr_table *mrt, bool all);
 static void ipmr_expire_process(unsigned long arg);
 
 #ifdef CONFIG_IP_MROUTE_MULTIPLE_TABLES
@@ -346,7 +346,7 @@ static struct mr_table *ipmr_new_table(s
 static void ipmr_free_table(struct mr_table *mrt)
 {
 	del_timer_sync(&mrt->ipmr_expire_timer);
-	mroute_clean_tables(mrt);
+	mroute_clean_tables(mrt, true);
 	kfree(mrt);
 }
 
@@ -1143,7 +1143,7 @@ static int ipmr_mfc_add(struct net *net,
  *	Close the multicast socket, and clear the vif tables etc
  */
 
-static void mroute_clean_tables(struct mr_table *mrt)
+static void mroute_clean_tables(struct mr_table *mrt, bool all)
 {
 	int i;
 	LIST_HEAD(list);
@@ -1152,8 +1152,9 @@ static void mroute_clean_tables(struct m
 	/* Shut down all active vif entries */
 
 	for (i = 0; i < mrt->maxvif; i++) {
-		if (!(mrt->vif_table[i].flags & VIFF_STATIC))
-			vif_delete(mrt, i, 0, &list);
+		if (!all && (mrt->vif_table[i].flags & VIFF_STATIC))
+			continue;
+		vif_delete(mrt, i, 0, &list);
 	}
 	unregister_netdevice_many(&list);
 
@@ -1161,7 +1162,7 @@ static void mroute_clean_tables(struct m
 
 	for (i = 0; i < MFC_LINES; i++) {
 		list_for_each_entry_safe(c, next, &mrt->mfc_cache_array[i], list) {
-			if (c->mfc_flags & MFC_STATIC)
+			if (!all && (c->mfc_flags & MFC_STATIC))
 				continue;
 			list_del_rcu(&c->list);
 			ipmr_cache_free(c);
@@ -1191,7 +1192,7 @@ static void mrtsock_destruct(struct sock
 		if (sk == rtnl_dereference(mrt->mroute_sk)) {
 			IPV4_DEVCONF_ALL(net, MC_FORWARDING)--;
 			RCU_INIT_POINTER(mrt->mroute_sk, NULL);
-			mroute_clean_tables(mrt);
+			mroute_clean_tables(mrt, false);
 		}
 	}
 	rtnl_unlock();

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