[NETFILTER]: ip_tables: compat code module refcounting fix

This patch fixes bug in iptables modules refcounting on compat error way.

As we are getting modules in check_compat_entry_size_and_hooks(), in case of
later error, we should put them all in translate_compat_table(), not  in the
compat_copy_entry_from_user() or compat_copy_match_from_user(), as it is now.

Signed-off-by: Dmitry Mishin <dim@openvz.org>
Acked-by: Vasily Averin <vvs@openvz.org>
Acked-by: Kirill Korotaev <dev@openvz.org>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 11 insertions, 25 deletions

diff --git a/net/ipv4/netfilter/ip_tables.c b/net/ipv4/netfilter/ip_tables.c
index 0f4835cf0e4d..8a455439b128 100644
--- a/net/ipv4/netfilter/ip_tables.c
+++ b/net/ipv4/netfilter/ip_tables.c
@@ -1527,7 +1527,7 @@ cleanup_matches:
 
 static inline int compat_copy_match_from_user(struct ipt_entry_match *m,
         void **dstptr, compat_uint_t *size, const char *name,
-        const struct ipt_ip *ip, unsigned int hookmask, int *i)
+        const struct ipt_ip *ip, unsigned int hookmask)
 {
         struct ipt_entry_match *dm;
         struct ipt_match *match;
@@ -1540,22 +1540,13 @@ static inline int compat_copy_match_from_user(struct ipt_entry_match *m,
         ret = xt_check_match(match, AF_INET, dm->u.match_size - sizeof(*dm),
                              name, hookmask, ip->proto,
                              ip->invflags & IPT_INV_PROTO);
-        if (ret)
-                goto err;
-
-        if (m->u.kernel.match->checkentry
+        if (!ret && m->u.kernel.match->checkentry
             && !m->u.kernel.match->checkentry(name, ip, match, dm->data,
                                               hookmask)) {
                 duprintf("ip_tables: check failed for `%s'.\n",
                          m->u.kernel.match->name);
                 ret = -EINVAL;
-                goto err;
         }
-        (*i)++;
-        return 0;
-
-err:
-        module_put(m->u.kernel.match->me);
         return ret;
 }
 
@@ -1567,19 +1558,18 @@ static int compat_copy_entry_from_user(struct ipt_entry *e, void **dstptr,
         struct ipt_target *target;
         struct ipt_entry *de;
         unsigned int origsize;
-        int ret, h, j;
+        int ret, h;
 
         ret = 0;
         origsize = *size;
         de = (struct ipt_entry *)*dstptr;
         memcpy(de, e, sizeof(struct ipt_entry));
 
-        j = 0;
         *dstptr += sizeof(struct compat_ipt_entry);
         ret = IPT_MATCH_ITERATE(e, compat_copy_match_from_user, dstptr, size,
-                        name, &de->ip, de->comefrom, &j);
+                        name, &de->ip, de->comefrom);
         if (ret)
-                goto cleanup_matches;
+                goto err;
         de->target_offset = e->target_offset - (origsize - *size);
         t = ipt_get_target(e);
         target = t->u.kernel.target;
@@ -1613,12 +1603,7 @@ static int compat_copy_entry_from_user(struct ipt_entry *e, void **dstptr,
                 goto err;
         }
         ret = 0;
-        return ret;
-
 err:
-        module_put(t->u.kernel.target->me);
-cleanup_matches:
-        IPT_MATCH_ITERATE(e, cleanup_match, &j);
         return ret;
 }
 
@@ -1632,7 +1617,7 @@ translate_compat_table(const char *name,
                 unsigned int *hook_entries,
                 unsigned int *underflows)
 {
-        unsigned int i;
+        unsigned int i, j;
         struct xt_table_info *newinfo, *info;
         void *pos, *entry0, *entry1;
         unsigned int size;
@@ -1650,21 +1635,21 @@ translate_compat_table(const char *name,
         }
 
         duprintf("translate_compat_table: size %u\n", info->size);
-        i = 0;
+        j = 0;
         xt_compat_lock(AF_INET);
         /* Walk through entries, checking offsets. */
         ret = IPT_ENTRY_ITERATE(entry0, total_size,
                                 check_compat_entry_size_and_hooks,
                                 info, &size, entry0,
                                 entry0 + total_size,
-                                hook_entries, underflows, &i, name);
+                                hook_entries, underflows, &j, name);
         if (ret != 0)
                 goto out_unlock;
 
         ret = -EINVAL;
-        if (i != number) {
+        if (j != number) {
                 duprintf("translate_compat_table: %u not %u entries\n",
-                         i, number);
+                         j, number);
                 goto out_unlock;
         }
 
@@ -1723,6 +1708,7 @@ translate_compat_table(const char *name,
 free_newinfo:
         xt_free_table_info(newinfo);
 out:
+        IPT_ENTRY_ITERATE(entry0, total_size, cleanup_entry, &j);
         return ret;
 out_unlock:
         compat_flush_offsets();