Merge branch 'fixes' of git://ftp.arm.linux.org.uk/~rmk/linux-arm

[firefly-linux-kernel-4.4.55.git] / net / netfilter / x_tables.c

diff --git a/net/netfilter/x_tables.c b/net/netfilter/x_tables.c
index d324fe71260c9f24b02507e4f429c0ba1e328d98..9b42b5ea6dcd68c8398c501aa5af81b6dfa83ae8 100644 (file)
--- a/net/netfilter/x_tables.c
+++ b/net/netfilter/x_tables.c
@@ -67,9 +67,6 @@ static const char *const xt_prefix[NFPROTO_NUMPROTO] = {
        [NFPROTO_IPV6]   = "ip6",
 };
 
-/* Allow this many total (re)entries. */
-static const unsigned int xt_jumpstack_multiplier = 2;
-
 /* Registration hooks for targets. */
 int xt_register_target(struct xt_target *target)
 {
@@ -688,8 +685,6 @@ void xt_free_table_info(struct xt_table_info *info)
                kvfree(info->jumpstack);
        }
 
-       free_percpu(info->stackptr);
-
        kvfree(info);
 }
 EXPORT_SYMBOL(xt_free_table_info);
@@ -732,15 +727,14 @@ EXPORT_SYMBOL_GPL(xt_compat_unlock);
 DEFINE_PER_CPU(seqcount_t, xt_recseq);
 EXPORT_PER_CPU_SYMBOL_GPL(xt_recseq);
 
+struct static_key xt_tee_enabled __read_mostly;
+EXPORT_SYMBOL_GPL(xt_tee_enabled);
+
 static int xt_jumpstack_alloc(struct xt_table_info *i)
 {
        unsigned int size;
        int cpu;
 
-       i->stackptr = alloc_percpu(unsigned int);
-       if (i->stackptr == NULL)
-               return -ENOMEM;
-
        size = sizeof(void **) * nr_cpu_ids;
        if (size > PAGE_SIZE)
                i->jumpstack = vzalloc(size);
@@ -749,8 +743,21 @@ static int xt_jumpstack_alloc(struct xt_table_info *i)
        if (i->jumpstack == NULL)
                return -ENOMEM;
 
-       i->stacksize *= xt_jumpstack_multiplier;
-       size = sizeof(void *) * i->stacksize;
+       /* ruleset without jumps -- no stack needed */
+       if (i->stacksize == 0)
+               return 0;
+
+       /* Jumpstack needs to be able to record two full callchains, one
+        * from the first rule set traversal, plus one table reentrancy
+        * via -j TEE without clobbering the callchain that brought us to
+        * TEE target.
+        *
+        * This is done by allocating two jumpstacks per cpu, on reentry
+        * the upper half of the stack is used.
+        *
+        * see the jumpstack setup in ipt_do_table() for more details.
+        */
+       size = sizeof(void *) * i->stacksize * 2u;
        for_each_possible_cpu(cpu) {
                if (size > PAGE_SIZE)
                        i->jumpstack[cpu] = vmalloc_node(size,