Patch "netfilter: x_tables: do compat validation via translate_table" has been added to the 4.4-stable tree

@@ -1233,19 +1233,17 @@ static inline void compat_release_entry(
 	module_put(t->u.kernel.target->me);
 }
 
-static inline int
+static int
 check_compat_entry_size_and_hooks(struct compat_arpt_entry *e,
 				  struct xt_table_info *newinfo,
 				  unsigned int *size,
 				  const unsigned char *base,
-				  const unsigned char *limit,
-				  const unsigned int *hook_entries,
-				  const unsigned int *underflows)
+				  const unsigned char *limit)
 {
 	struct xt_entry_target *t;
 	struct xt_target *target;
 	unsigned int entry_offset;
-	int ret, off, h;
+	int ret, off;
 
 	duprintf("check_compat_entry_size_and_hooks %p\n", e);
 	if ((unsigned long)e % __alignof__(struct compat_arpt_entry) != 0 ||

@@ -1290,17 +1288,6 @@ check_compat_entry_size_and_hooks(struct
 	if (ret)
 		goto release_target;
 
-	/* Check hooks & underflows */
-	for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
-		if ((unsigned char *)e - base == hook_entries[h])
-			newinfo->hook_entry[h] = hook_entries[h];
-		if ((unsigned char *)e - base == underflows[h])
-			newinfo->underflow[h] = underflows[h];
-	}
-
-	/* Clear counters and comefrom */
-	memset(&e->counters, 0, sizeof(e->counters));
-	e->comefrom = 0;
 	return 0;
 
 release_target:

@@ -1350,7 +1337,7 @@ static int translate_compat_table(struct
 	struct xt_table_info *newinfo, *info;
 	void *pos, *entry0, *entry1;
 	struct compat_arpt_entry *iter0;
-	struct arpt_entry *iter1;
+	struct arpt_replace repl;
 	unsigned int size;
 	int ret = 0;
 

@@ -1359,12 +1346,6 @@ static int translate_compat_table(struct
 	size = compatr->size;
 	info->number = compatr->num_entries;
 
-	/* Init all hooks to impossible value. */
-	for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
-		info->hook_entry[i] = 0xFFFFFFFF;
-		info->underflow[i] = 0xFFFFFFFF;
-	}
-
 	duprintf("translate_compat_table: size %u\n", info->size);
 	j = 0;
 	xt_compat_lock(NFPROTO_ARP);

@@ -1373,9 +1354,7 @@ static int translate_compat_table(struct
 	xt_entry_foreach(iter0, entry0, compatr->size) {
 		ret = check_compat_entry_size_and_hooks(iter0, info, &size,
 							entry0,
-							entry0 + compatr->size,
-							compatr->hook_entry,
-							compatr->underflow);
+							entry0 + compatr->size);
 		if (ret != 0)
 			goto out_unlock;
 		++j;

@@ -1388,23 +1367,6 @@ static int translate_compat_table(struct
 		goto out_unlock;
 	}
 
-	/* Check hooks all assigned */
-	for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
-		/* Only hooks which are valid */
-		if (!(compatr->valid_hooks & (1 << i)))
-			continue;
-		if (info->hook_entry[i] == 0xFFFFFFFF) {
-			duprintf("Invalid hook entry %u %u\n",
-				 i, info->hook_entry[i]);
-			goto out_unlock;
-		}
-		if (info->underflow[i] == 0xFFFFFFFF) {
-			duprintf("Invalid underflow %u %u\n",
-				 i, info->underflow[i]);
-			goto out_unlock;
-		}
-	}
-
 	ret = -ENOMEM;
 	newinfo = xt_alloc_table_info(size);
 	if (!newinfo)

@@ -1421,55 +1383,26 @@ static int translate_compat_table(struct
 	xt_entry_foreach(iter0, entry0, compatr->size)
 		compat_copy_entry_from_user(iter0, &pos, &size,
 					    newinfo, entry1);
+
+	/* all module references in entry0 are now gone */
+
 	xt_compat_flush_offsets(NFPROTO_ARP);
 	xt_compat_unlock(NFPROTO_ARP);
 
-	ret = -ELOOP;
-	if (!mark_source_chains(newinfo, compatr->valid_hooks, entry1))
-		goto free_newinfo;
-
-	i = 0;
-	xt_entry_foreach(iter1, entry1, newinfo->size) {
-		iter1->counters.pcnt = xt_percpu_counter_alloc();
-		if (IS_ERR_VALUE(iter1->counters.pcnt)) {
-			ret = -ENOMEM;
-			break;
-		}
+	memcpy(&repl, compatr, sizeof(*compatr));
 
-		ret = check_target(iter1, compatr->name);
-		if (ret != 0) {
-			xt_percpu_counter_free(iter1->counters.pcnt);
-			break;
-		}
-		++i;
-		if (strcmp(arpt_get_target(iter1)->u.user.name,
-		    XT_ERROR_TARGET) == 0)
-			++newinfo->stacksize;
-	}
-	if (ret) {
-		/*
-		 * The first i matches need cleanup_entry (calls ->destroy)
-		 * because they had called ->check already. The other j-i
-		 * entries need only release.
-		 */
-		int skip = i;
-		j -= i;
-		xt_entry_foreach(iter0, entry0, newinfo->size) {
-			if (skip-- > 0)
-				continue;
-			if (j-- == 0)
-				break;
-			compat_release_entry(iter0);
-		}
-		xt_entry_foreach(iter1, entry1, newinfo->size) {
-			if (i-- == 0)
-				break;
-			cleanup_entry(iter1);
-		}
-		xt_free_table_info(newinfo);
-		return ret;
+	for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
+		repl.hook_entry[i] = newinfo->hook_entry[i];
+		repl.underflow[i] = newinfo->underflow[i];
 	}
 
+	repl.num_counters = 0;
+	repl.counters = NULL;
+	repl.size = newinfo->size;
+	ret = translate_table(newinfo, entry1, &repl);
+	if (ret)
+		goto free_newinfo;
+
 	*pinfo = newinfo;
 	*pentry0 = entry1;
 	xt_free_table_info(info);

@@ -1477,17 +1410,16 @@ static int translate_compat_table(struct
 
 free_newinfo:
 	xt_free_table_info(newinfo);
-out:
+	return ret;
+out_unlock:
+	xt_compat_flush_offsets(NFPROTO_ARP);
+	xt_compat_unlock(NFPROTO_ARP);
 	xt_entry_foreach(iter0, entry0, compatr->size) {
 		if (j-- == 0)
 			break;
 		compat_release_entry(iter0);
 	}
 	return ret;
-out_unlock:
-	xt_compat_flush_offsets(NFPROTO_ARP);
-	xt_compat_unlock(NFPROTO_ARP);
-	goto out;
 }
 
 static int compat_do_replace(struct net *net, void __user *user,

239 lines not on this page · raw message

227 lines not on this page · raw message

@@ -532,6 +532,7 @@ void xt_compat_match_from_user(struct xt
 	struct compat_xt_entry_match *cm = (struct compat_xt_entry_match *)m;
 	int pad, off = xt_compat_match_offset(match);
 	u_int16_t msize = cm->u.user.match_size;
+	char name[sizeof(m->u.user.name)];
 
 	m = *dstptr;
 	memcpy(m, cm, sizeof(*cm));

@@ -545,6 +546,9 @@ void xt_compat_match_from_user(struct xt
 
 	msize += off;
 	m->u.user.match_size = msize;
+	strlcpy(name, match->name, sizeof(name));
+	module_put(match->me);
+	strncpy(m->u.user.name, name, sizeof(m->u.user.name));
 
 	*size += off;
 	*dstptr += msize;

@@ -762,6 +766,7 @@ void xt_compat_target_from_user(struct x
 	struct compat_xt_entry_target *ct = (struct compat_xt_entry_target *)t;
 	int pad, off = xt_compat_target_offset(target);
 	u_int16_t tsize = ct->u.user.target_size;
+	char name[sizeof(t->u.user.name)];
 
 	t = *dstptr;
 	memcpy(t, ct, sizeof(*ct));

@@ -775,6 +780,9 @@ void xt_compat_target_from_user(struct x
 
 	tsize += off;
 	t->u.user.target_size = tsize;
+	strlcpy(name, target->name, sizeof(name));
+	module_put(target->me);
+	strncpy(t->u.user.name, name, sizeof(t->u.user.name));
 
 	*size += off;
 	*dstptr += tsize;