[NETFILTER]: ip_tables: ipt and ipt_compat checks unification

Matches and targets verification is duplicated in normal and compat processing
ways. This patch refactors code in order to remove this.
Signed-off-by: NDmitry Mishin <dim@openvz.org>
Signed-off-by: NPatrick McHardy <kaber@trash.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/ipv4/netfilter/ip_tables.c

@@ -484,7 +484,47 @@ cleanup_match(struct ipt_entry_match *m, unsigned int *i)
 }
 
 static inline int
-check_match(struct ipt_entry_match *m,
+check_entry(struct ipt_entry *e, const char *name)
+{
+	struct ipt_entry_target *t;
+
+	if (!ip_checkentry(&e->ip)) {
+		duprintf("ip_tables: ip check failed %p %s.\n", e, name);
+		return -EINVAL;
+	}
+
+	if (e->target_offset + sizeof(struct ipt_entry_target) > e->next_offset)
+		return -EINVAL;
+
+	t = ipt_get_target(e);
+	if (e->target_offset + t->u.target_size > e->next_offset)
+		return -EINVAL;
+
+	return 0;
+}
+
+static inline int 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: check failed for `%s'.\n",
+			 m->u.kernel.match->name);
+		ret = -EINVAL;
+	}
+	return ret;
+}
+
+static inline int
+find_check_match(struct ipt_entry_match *m,
 	    const char *name,
 	    const struct ipt_ip *ip,
 	    unsigned int hookmask,
@@ -497,26 +537,15 @@ check_match(struct ipt_entry_match *m,
 						   m->u.user.revision),
 					"ipt_%s", m->u.user.name);
 	if (IS_ERR(match) || !match) {
-		duprintf("check_match: `%s' not found\n", m->u.user.name);
+		duprintf("find_check_match: `%s' not found\n", m->u.user.name);
 		return match ? PTR_ERR(match) : -ENOENT;
 	}
 	m->u.kernel.match = match;
 
-	ret = xt_check_match(match, AF_INET, m->u.match_size - sizeof(*m),
-			     name, hookmask, ip->proto,
-			     ip->invflags & IPT_INV_PROTO);
+	ret = check_match(m, name, ip, hookmask);
 	if (ret)
 		goto err;
 
-	if (m->u.kernel.match->checkentry
-	    && !m->u.kernel.match->checkentry(name, ip, match, m->data,
-					      hookmask)) {
-		duprintf("ip_tables: check failed for `%s'.\n",
-			 m->u.kernel.match->name);
-		ret = -EINVAL;
-		goto err;
-	}
-
 	(*i)++;
 	return 0;
 err:
@@ -524,10 +553,29 @@ check_match(struct ipt_entry_match *m,
 	return ret;
 }
 
-static struct ipt_target ipt_standard_target;
+static inline int check_target(struct ipt_entry *e, const char *name)
+{
+ 	struct ipt_entry_target *t;
+ 	struct ipt_target *target;
+ 	int ret;
+
+	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 && t->u.kernel.target->checkentry
+		   && !t->u.kernel.target->checkentry(name, e, target,
+						      t->data, e->comefrom)) {
+		duprintf("ip_tables: check failed for `%s'.\n",
+			 t->u.kernel.target->name);
+		ret = -EINVAL;
+	}
+	return ret;
+}
 
 static inline int
-check_entry(struct ipt_entry *e, const char *name, unsigned int size,
+find_check_entry(struct ipt_entry *e, const char *name, unsigned int size,
 	    unsigned int *i)
 {
 	struct ipt_entry_target *t;
@@ -535,49 +583,32 @@ check_entry(struct ipt_entry *e, const char *name, unsigned int size,
 	int ret;
 	unsigned int j;
 
-	if (!ip_checkentry(&e->ip)) {
-		duprintf("ip_tables: ip check failed %p %s.\n", e, name);
-		return -EINVAL;
-	}
-
-	if (e->target_offset + sizeof(struct ipt_entry_target) > e->next_offset)
-		return -EINVAL;
+	ret = check_entry(e, name);
+	if (ret)
+		return ret;
 
 	j = 0;
-	ret = IPT_MATCH_ITERATE(e, check_match, name, &e->ip, e->comefrom, &j);
+	ret = IPT_MATCH_ITERATE(e, find_check_match, name, &e->ip,
+							e->comefrom, &j);
 	if (ret != 0)
 		goto cleanup_matches;
 
 	t = ipt_get_target(e);
-	ret = -EINVAL;
-	if (e->target_offset + t->u.target_size > e->next_offset)
-			goto cleanup_matches;
 	target = try_then_request_module(xt_find_target(AF_INET,
 						     t->u.user.name,
 						     t->u.user.revision),
 					 "ipt_%s", t->u.user.name);
 	if (IS_ERR(target) || !target) {
-		duprintf("check_entry: `%s' not found\n", t->u.user.name);
+		duprintf("find_check_entry: `%s' not found\n", t->u.user.name);
 		ret = target ? PTR_ERR(target) : -ENOENT;
 		goto cleanup_matches;
 	}
 	t->u.kernel.target = 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);
+	ret = check_target(e, name);
 	if (ret)
 		goto err;
 
-	if (t->u.kernel.target->checkentry
-		   && !t->u.kernel.target->checkentry(name, e, target, t->data,
-						      e->comefrom)) {
-		duprintf("ip_tables: check failed for `%s'.\n",
-			 t->u.kernel.target->name);
-		ret = -EINVAL;
-		goto err;
-	}
-
 	(*i)++;
 	return 0;
  err:
@@ -712,7 +743,7 @@ translate_table(const char *name,
 	/* Finally, each sanity check must pass */
 	i = 0;
 	ret = IPT_ENTRY_ITERATE(entry0, newinfo->size,
-				check_entry, name, size, &i);
+				find_check_entry, name, size, &i);
 
 	if (ret != 0) {
 		IPT_ENTRY_ITERATE(entry0, newinfo->size,
@@ -1452,14 +1483,9 @@ check_compat_entry_size_and_hooks(struct ipt_entry *e,
 		return -EINVAL;
 	}
 
-	if (!ip_checkentry(&e->ip)) {
-		duprintf("ip_tables: ip check failed %p %s.\n", e, name);
-		return -EINVAL;
-	}
-
-	if (e->target_offset + sizeof(struct compat_xt_entry_target) >
-								e->next_offset)
-		return -EINVAL;
+	ret = check_entry(e, name);
+	if (ret)
+		return ret;
 
 	off = 0;
 	entry_offset = (void *)e - (void *)base;
@@ -1470,15 +1496,13 @@ check_compat_entry_size_and_hooks(struct ipt_entry *e,
 		goto cleanup_matches;
 
 	t = ipt_get_target(e);
-	ret = -EINVAL;
-	if (e->target_offset + t->u.target_size > e->next_offset)
-			goto cleanup_matches;
 	target = try_then_request_module(xt_find_target(AF_INET,
 						     t->u.user.name,
 						     t->u.user.revision),
 					 "ipt_%s", t->u.user.name);
 	if (IS_ERR(target) || !target) {
-		duprintf("check_entry: `%s' not found\n", t->u.user.name);
+		duprintf("check_compat_entry_size_and_hooks: `%s' not found\n",
+							t->u.user.name);
 		ret = target ? PTR_ERR(target) : -ENOENT;
 		goto cleanup_matches;
 	}
@@ -1555,57 +1579,15 @@ static int compat_copy_entry_from_user(struct ipt_entry *e, void **dstptr,
 	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(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 && 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;
-	}
-	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);
+	ret = IPT_MATCH_ITERATE(e, check_match, name, &e->ip, e->comefrom);
 	if (ret)
 		return ret;
 
-	return compat_check_target(e, name);
+	return check_target(e, name);
 }
 
 static int