Merge tag 'thunderbolt-for-v7.1-rc5' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/westeri/thunderbolt into usb-linus

Mika writes:

thunderbolt: Fixes for v7.1-rc5

This includes three patches that harden the XDomain property parser
against possible malicious hosts.

All these have been in linux-next with no reported issues.

* tag 'thunderbolt-for-v7.1-rc5' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/westeri/thunderbolt:
  thunderbolt: property: Cap recursion depth in __tb_property_parse_dir()
  thunderbolt: property: Reject dir_len < 4 to prevent size_t underflow
  thunderbolt: property: Reject u32 wrap in tb_property_entry_valid()

1 files changed, 23 insertions, 9 deletions

diff --git a/drivers/thunderbolt/property.c b/drivers/thunderbolt/property.c
index 50cbfc92fe65..da2c59a17db5 100644
--- a/drivers/thunderbolt/property.c
+++ b/drivers/thunderbolt/property.c
@@ -8,6 +8,7 @@
  */
 
 #include <linux/err.h>
+#include <linux/overflow.h>
 #include <linux/slab.h>
 #include <linux/string.h>
 #include <linux/uuid.h>
@@ -34,10 +35,11 @@ struct tb_property_dir_entry {
 };
 
 #define TB_PROPERTY_ROOTDIR_MAGIC	0x55584401
+#define TB_PROPERTY_MAX_DEPTH		8
 
 static struct tb_property_dir *__tb_property_parse_dir(const u32 *block,
 	size_t block_len, unsigned int dir_offset, size_t dir_len,
-	bool is_root);
+	bool is_root, unsigned int depth);
 
 static inline void parse_dwdata(void *dst, const void *src, size_t dwords)
 {
@@ -52,13 +54,16 @@ static inline void format_dwdata(void *dst, const void *src, size_t dwords)
 static bool tb_property_entry_valid(const struct tb_property_entry *entry,
 				  size_t block_len)
 {
+	u32 end;
+
 	switch (entry->type) {
 	case TB_PROPERTY_TYPE_DIRECTORY:
 	case TB_PROPERTY_TYPE_DATA:
 	case TB_PROPERTY_TYPE_TEXT:
 		if (entry->length > block_len)
 			return false;
-		if (entry->value + entry->length > block_len)
+		if (check_add_overflow(entry->value, entry->length, &end) ||
+		    end > block_len)
 			return false;
 		break;
 
@@ -93,7 +98,8 @@ tb_property_alloc(const char *key, enum tb_property_type type)
 }
 
 static struct tb_property *tb_property_parse(const u32 *block, size_t block_len,
-					const struct tb_property_entry *entry)
+					const struct tb_property_entry *entry,
+					unsigned int depth)
 {
 	char key[TB_PROPERTY_KEY_SIZE + 1];
 	struct tb_property *property;
@@ -114,7 +120,7 @@ static struct tb_property *tb_property_parse(const u32 *block, size_t block_len,
 	switch (property->type) {
 	case TB_PROPERTY_TYPE_DIRECTORY:
 		dir = __tb_property_parse_dir(block, block_len, entry->value,
-					      entry->length, false);
+					      entry->length, false, depth + 1);
 		if (!dir) {
 			kfree(property);
 			return NULL;
@@ -159,21 +165,31 @@ static struct tb_property *tb_property_parse(const u32 *block, size_t block_len,
 }
 
 static struct tb_property_dir *__tb_property_parse_dir(const u32 *block,
-	size_t block_len, unsigned int dir_offset, size_t dir_len, bool is_root)
+	size_t block_len, unsigned int dir_offset, size_t dir_len, bool is_root,
+	unsigned int depth)
 {
 	const struct tb_property_entry *entries;
 	size_t i, content_len, nentries;
 	unsigned int content_offset;
 	struct tb_property_dir *dir;
 
+	if (depth > TB_PROPERTY_MAX_DEPTH)
+		return NULL;
+
 	dir = kzalloc_obj(*dir);
 	if (!dir)
 		return NULL;
 
+	INIT_LIST_HEAD(&dir->properties);
+
 	if (is_root) {
 		content_offset = dir_offset + 2;
 		content_len = dir_len;
 	} else {
+		if (dir_len < 4) {
+			tb_property_free_dir(dir);
+			return NULL;
+		}
 		dir->uuid = kmemdup(&block[dir_offset], sizeof(*dir->uuid),
 				    GFP_KERNEL);
 		if (!dir->uuid) {
@@ -187,12 +203,10 @@ static struct tb_property_dir *__tb_property_parse_dir(const u32 *block,
 	entries = (const struct tb_property_entry *)&block[content_offset];
 	nentries = content_len / (sizeof(*entries) / 4);
 
-	INIT_LIST_HEAD(&dir->properties);
-
 	for (i = 0; i < nentries; i++) {
 		struct tb_property *property;
 
-		property = tb_property_parse(block, block_len, &entries[i]);
+		property = tb_property_parse(block, block_len, &entries[i], depth);
 		if (!property) {
 			tb_property_free_dir(dir);
 			return NULL;
@@ -231,7 +245,7 @@ struct tb_property_dir *tb_property_parse_dir(const u32 *block,
 		return NULL;
 
 	return __tb_property_parse_dir(block, block_len, 0, rootdir->length,
-				       true);
+				       true, 0);
 }
 
 /**