[NETFILTER]: Fix iptables compat hook validation

In compat mode, matches and targets valid hooks checks always successful due
to not initialized e->comefrom field yet. This patch separates this checks from
translation code and moves them after mark_source_chains() call, where these
marks are initialized.

Signed-off-by: Dmitry Mishin <dim@openvz.org>
Signed-off-by; Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 51 insertions, 27 deletions

diff --git a/net/ipv4/netfilter/ip_tables.c b/net/ipv4/netfilter/ip_tables.c
index 2bddf8491982..0ff2956d35e5 100644
--- a/net/ipv4/netfilter/ip_tables.c
+++ b/net/ipv4/netfilter/ip_tables.c
@@ -1516,25 +1516,8 @@ 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)
 {
-        struct ipt_entry_match *dm;
-        struct ipt_match *match;
-        int ret;
-
-        dm = (struct ipt_entry_match *)*dstptr;
-        match = m->u.kernel.match;
         xt_compat_match_from_user(m, dstptr, size);
-
-        ret = xt_check_match(match, AF_INET, dm->u.match_size - sizeof(*dm),
-                             name, hookmask, ip->proto,
-                             ip->invflags & IPT_INV_PROTO);
-        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;
-        }
-        return ret;
+        return 0;
 }
 
 static int compat_copy_entry_from_user(struct ipt_entry *e, void **dstptr,
@@ -1556,7 +1539,7 @@ static int compat_copy_entry_from_user(struct ipt_entry *e, void **dstptr,
         ret = IPT_MATCH_ITERATE(e, compat_copy_match_from_user, dstptr, size,
                         name, &de->ip, de->comefrom);
         if (ret)
-                goto err;
+                return ret;
         de->target_offset = e->target_offset - (origsize - *size);
         t = ipt_get_target(e);
         target = t->u.kernel.target;
@@ -1569,26 +1552,62 @@ static int compat_copy_entry_from_user(struct ipt_entry *e, void **dstptr,
                 if ((unsigned char *)de - base < newinfo->underflow[h])
                         newinfo->underflow[h] -= origsize - *size;
         }
+        return ret;
+}
+
+static inline int compat_check_match(struct ipt_entry_match *m, const char *name,
+                                const struct ipt_ip *ip, unsigned int hookmask)
+{
+        struct ipt_match *match;
+        int ret;
+
+        match = m->u.kernel.match;
+        ret = xt_check_match(match, AF_INET, m->u.match_size - sizeof(*m),
+                             name, hookmask, ip->proto,
+                             ip->invflags & IPT_INV_PROTO);
+        if (!ret && m->u.kernel.match->checkentry
+            && !m->u.kernel.match->checkentry(name, ip, match, m->data,
+                                              hookmask)) {
+                duprintf("ip_tables: compat: check failed for `%s'.\n",
+                         m->u.kernel.match->name);
+                ret = -EINVAL;
+        }
+        return ret;
+}
+
+static inline int compat_check_target(struct ipt_entry *e, const char *name)
+{
+        struct ipt_entry_target *t;
+        struct ipt_target *target;
+        int ret;
 
-        t = ipt_get_target(de);
+        t = ipt_get_target(e);
         target = t->u.kernel.target;
         ret = xt_check_target(target, AF_INET, t->u.target_size - sizeof(*t),
                               name, e->comefrom, e->ip.proto,
                               e->ip.invflags & IPT_INV_PROTO);
-        if (ret)
-                goto err;
-
-        if (t->u.kernel.target->checkentry
-                   && !t->u.kernel.target->checkentry(name, de, target,
-                                                      t->data, de->comefrom)) {
+        if (!ret && t->u.kernel.target->checkentry
+                   && !t->u.kernel.target->checkentry(name, e, target,
+                                                      t->data, e->comefrom)) {
                 duprintf("ip_tables: compat: check failed for `%s'.\n",
                          t->u.kernel.target->name);
                 ret = -EINVAL;
         }
-err:
         return ret;
 }
 
+static inline int compat_check_entry(struct ipt_entry *e, const char *name)
+{
+        int ret;
+
+        ret = IPT_MATCH_ITERATE(e, compat_check_match, name, &e->ip,
+                                                                e->comefrom);
+        if (ret)
+                return ret;
+
+        return compat_check_target(e, name);
+}
+
 static int
 translate_compat_table(const char *name,
                 unsigned int valid_hooks,
@@ -1677,6 +1696,11 @@ translate_compat_table(const char *name,
         if (!mark_source_chains(newinfo, valid_hooks, entry1))
                 goto free_newinfo;
 
+        ret = IPT_ENTRY_ITERATE(entry1, newinfo->size, compat_check_entry,
+                                                                        name);
+        if (ret)
+                goto free_newinfo;
+
         /* And one copy for every other CPU */
         for_each_possible_cpu(i)
                 if (newinfo->entries[i] && newinfo->entries[i] != entry1)