[INET]: Small possible memory leak in FIB rules

This patch fixes a small memory leak. Default fib rules can be deleted by
the user if the rule does not carry FIB_RULE_PERMANENT flag, f.e. by
	ip rule flush

Such a rule will not be freed as the ref-counter has 2 on start and becomes
clearly unreachable after removal.

Signed-off-by: Denis V. Lunev <den@openvz.org>
Acked-by: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
Signed-off-by: David S. Miller <davem@davemloft.net>

5 files changed, 62 insertions, 64 deletions

diff --git a/include/net/fib_rules.h b/include/net/fib_rules.h
index 017aebd90683..41a301e38643 100644
--- a/include/net/fib_rules.h
+++ b/include/net/fib_rules.h
@@ -107,4 +107,7 @@ extern int			fib_rules_unregister(struct fib_rules_ops *);
 extern int                      fib_rules_lookup(struct fib_rules_ops *,
                                                  struct flowi *, int flags,
                                                  struct fib_lookup_arg *);
+extern int                      fib_default_rule_add(struct fib_rules_ops *,
+                                                     u32 pref, u32 table,
+                                                     u32 flags);
 #endif
diff --git a/net/core/fib_rules.c b/net/core/fib_rules.c
index 13de6f53f098..848132b6cb73 100644
--- a/net/core/fib_rules.c
+++ b/net/core/fib_rules.c
@@ -18,6 +18,28 @@
 static LIST_HEAD(rules_ops);
 static DEFINE_SPINLOCK(rules_mod_lock);
 
+int fib_default_rule_add(struct fib_rules_ops *ops,
+                         u32 pref, u32 table, u32 flags)
+{
+        struct fib_rule *r;
+
+        r = kzalloc(ops->rule_size, GFP_KERNEL);
+        if (r == NULL)
+                return -ENOMEM;
+
+        atomic_set(&r->refcnt, 1);
+        r->action = FR_ACT_TO_TBL;
+        r->pref = pref;
+        r->table = table;
+        r->flags = flags;
+
+        /* The lock is not required here, the list in unreacheable
+         * at the moment this function is called */
+        list_add_tail(&r->list, &ops->rules_list);
+        return 0;
+}
+EXPORT_SYMBOL(fib_default_rule_add);
+
 static void notify_rule_change(int event, struct fib_rule *rule,
                                struct fib_rules_ops *ops, struct nlmsghdr *nlh,
                                u32 pid);
diff --git a/net/decnet/dn_rules.c b/net/decnet/dn_rules.c
index ddd3f04f0919..ffebea04cc99 100644
--- a/net/decnet/dn_rules.c
+++ b/net/decnet/dn_rules.c
@@ -48,15 +48,6 @@ struct dn_fib_rule
         u8                      flags;
 };
 
-static struct dn_fib_rule default_rule = {
-        .common = {
-                .refcnt =               ATOMIC_INIT(2),
-                .pref =                 0x7fff,
-                .table =                RT_TABLE_MAIN,
-                .action =               FR_ACT_TO_TBL,
-        },
-};
-
 
 int dn_fib_lookup(struct flowi *flp, struct dn_fib_res *res)
 {
@@ -262,8 +253,8 @@ static struct fib_rules_ops dn_fib_rules_ops = {
 
 void __init dn_fib_rules_init(void)
 {
-        list_add_tail(&default_rule.common.list,
-                        &dn_fib_rules_ops.rules_list);
+        BUG_ON(fib_default_rule_add(&dn_fib_rules_ops, 0x7fff,
+                                    RT_TABLE_MAIN, 0));
         fib_rules_register(&dn_fib_rules_ops);
 }
 
diff --git a/net/ipv4/fib_rules.c b/net/ipv4/fib_rules.c
index f16839c6a721..a0ada3a8d8dd 100644
--- a/net/ipv4/fib_rules.c
+++ b/net/ipv4/fib_rules.c
@@ -49,33 +49,6 @@ struct fib4_rule
 #endif
 };
 
-static struct fib4_rule default_rule = {
-        .common = {
-                .refcnt =       ATOMIC_INIT(2),
-                .pref =         0x7FFF,
-                .table =        RT_TABLE_DEFAULT,
-                .action =       FR_ACT_TO_TBL,
-        },
-};
-
-static struct fib4_rule main_rule = {
-        .common = {
-                .refcnt =       ATOMIC_INIT(2),
-                .pref =         0x7FFE,
-                .table =        RT_TABLE_MAIN,
-                .action =       FR_ACT_TO_TBL,
-        },
-};
-
-static struct fib4_rule local_rule = {
-        .common = {
-                .refcnt =       ATOMIC_INIT(2),
-                .table =        RT_TABLE_LOCAL,
-                .action =       FR_ACT_TO_TBL,
-                .flags =        FIB_RULE_PERMANENT,
-        },
-};
-
 #ifdef CONFIG_NET_CLS_ROUTE
 u32 fib_rules_tclass(struct fib_result *res)
 {
@@ -319,11 +292,27 @@ static struct fib_rules_ops fib4_rules_ops = {
         .owner          = THIS_MODULE,
 };
 
-void __init fib4_rules_init(void)
+static int __init fib_default_rules_init(void)
 {
-        list_add_tail(&local_rule.common.list, &fib4_rules_ops.rules_list);
-        list_add_tail(&main_rule.common.list, &fib4_rules_ops.rules_list);
-        list_add_tail(&default_rule.common.list, &fib4_rules_ops.rules_list);
+        int err;
+
+        err = fib_default_rule_add(&fib4_rules_ops, 0,
+                                   RT_TABLE_LOCAL, FIB_RULE_PERMANENT);
+        if (err < 0)
+                return err;
+        err = fib_default_rule_add(&fib4_rules_ops, 0x7FFE,
+                                   RT_TABLE_MAIN, 0);
+        if (err < 0)
+                return err;
+        err = fib_default_rule_add(&fib4_rules_ops, 0x7FFF,
+                                   RT_TABLE_DEFAULT, 0);
+        if (err < 0)
+                return err;
+        return 0;
+}
 
+void __init fib4_rules_init(void)
+{
+        BUG_ON(fib_default_rules_init());
         fib_rules_register(&fib4_rules_ops);
 }
diff --git a/net/ipv6/fib6_rules.c b/net/ipv6/fib6_rules.c
index 706622af206f..428c6b0e26d8 100644
--- a/net/ipv6/fib6_rules.c
+++ b/net/ipv6/fib6_rules.c
@@ -31,25 +31,6 @@ struct fib6_rule
 
 static struct fib_rules_ops fib6_rules_ops;
 
-static struct fib6_rule main_rule = {
-        .common = {
-                .refcnt =       ATOMIC_INIT(2),
-                .pref =         0x7FFE,
-                .action =       FR_ACT_TO_TBL,
-                .table =        RT6_TABLE_MAIN,
-        },
-};
-
-static struct fib6_rule local_rule = {
-        .common = {
-                .refcnt =       ATOMIC_INIT(2),
-                .pref =         0,
-                .action =       FR_ACT_TO_TBL,
-                .table =        RT6_TABLE_LOCAL,
-                .flags =        FIB_RULE_PERMANENT,
-        },
-};
-
 struct dst_entry *fib6_rule_lookup(struct flowi *fl, int flags,
                                    pol_lookup_t lookup)
 {
@@ -270,11 +251,23 @@ static struct fib_rules_ops fib6_rules_ops = {
         .owner                  = THIS_MODULE,
 };
 
-void __init fib6_rules_init(void)
+static int __init fib6_default_rules_init(void)
 {
-        list_add_tail(&local_rule.common.list, &fib6_rules_ops.rules_list);
-        list_add_tail(&main_rule.common.list, &fib6_rules_ops.rules_list);
+        int err;
+
+        err = fib_default_rule_add(&fib6_rules_ops, 0,
+                                   RT6_TABLE_LOCAL, FIB_RULE_PERMANENT);
+        if (err < 0)
+                return err;
+        err = fib_default_rule_add(&fib6_rules_ops, 0x7FFE, RT6_TABLE_MAIN, 0);
+        if (err < 0)
+                return err;
+        return 0;
+}
 
+void __init fib6_rules_init(void)
+{
+        BUG_ON(fib6_default_rules_init());
         fib_rules_register(&fib6_rules_ops);
 }