Merge tag 'exfat-for-6.5-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/linkinjeon/exfat

Pull exfat fixes from Namjae Jeon:

 - Fix page allocation failure from allocation bitmap by using
   kvmalloc_array/kvfree

 - Add the check to validate if filename entries exceeds max filename
   length

 - Fix potential deadlock condition from dir_emit*()

* tag 'exfat-for-6.5-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/linkinjeon/exfat:
  exfat: release s_lock before calling dir_emit()
  exfat: check if filename entries exceeds max filename length
  exfat: use kvmalloc_array/kvfree instead of kmalloc_array/kfree

fs/exfat/balloc.c

@@ -69,7 +69,7 @@ static int exfat_allocate_bitmap(struct super_block *sb,
 	}
 	sbi->map_sectors = ((need_map_size - 1) >>
 			(sb->s_blocksize_bits)) + 1;
-	sbi->vol_amap = kmalloc_array(sbi->map_sectors,
+	sbi->vol_amap = kvmalloc_array(sbi->map_sectors,
 				sizeof(struct buffer_head *), GFP_KERNEL);
 	if (!sbi->vol_amap)
 		return -ENOMEM;
@@ -84,7 +84,7 @@ static int exfat_allocate_bitmap(struct super_block *sb,
 			while (j < i)
 				brelse(sbi->vol_amap[j++]);
 
-			kfree(sbi->vol_amap);
+			kvfree(sbi->vol_amap);
 			sbi->vol_amap = NULL;
 			return -EIO;
 		}
@@ -138,7 +138,7 @@ void exfat_free_bitmap(struct exfat_sb_info *sbi)
 	for (i = 0; i < sbi->map_sectors; i++)
 		__brelse(sbi->vol_amap[i]);
 
-	kfree(sbi->vol_amap);
+	kvfree(sbi->vol_amap);
 }
 
 int exfat_set_bitmap(struct inode *inode, unsigned int clu, bool sync)

fs/exfat/dir.c

@@ -34,6 +34,7 @@ static int exfat_get_uniname_from_ext_entry(struct super_block *sb,
 {
 	int i, err;
 	struct exfat_entry_set_cache es;
+	unsigned int uni_len = 0, len;
 
 	err = exfat_get_dentry_set(&es, sb, p_dir, entry, ES_ALL_ENTRIES);
 	if (err)
@@ -52,7 +53,10 @@ static int exfat_get_uniname_from_ext_entry(struct super_block *sb,
 		if (exfat_get_entry_type(ep) != TYPE_EXTEND)
 			break;
 
-		exfat_extract_uni_name(ep, uniname);
+		len = exfat_extract_uni_name(ep, uniname);
+		uni_len += len;
+		if (len != EXFAT_FILE_NAME_LEN || uni_len >= MAX_NAME_LENGTH)
+			break;
 		uniname += EXFAT_FILE_NAME_LEN;
 	}
 
@@ -214,7 +218,10 @@ static void exfat_free_namebuf(struct exfat_dentry_namebuf *nb)
 	exfat_init_namebuf(nb);
 }
 
-/* skip iterating emit_dots when dir is empty */
+/*
+ * Before calling dir_emit*(), sbi->s_lock should be released
+ * because page fault can occur in dir_emit*().
+ */
 #define ITER_POS_FILLED_DOTS    (2)
 static int exfat_iterate(struct file *file, struct dir_context *ctx)
 {
@@ -229,11 +236,10 @@ static int exfat_iterate(struct file *file, struct dir_context *ctx)
 	int err = 0, fake_offset = 0;
 
 	exfat_init_namebuf(nb);
-	mutex_lock(&EXFAT_SB(sb)->s_lock);
 
 	cpos = ctx->pos;
 	if (!dir_emit_dots(file, ctx))
-		goto unlock;
+		goto out;
 
 	if (ctx->pos == ITER_POS_FILLED_DOTS) {
 		cpos = 0;
@@ -245,16 +251,18 @@ static int exfat_iterate(struct file *file, struct dir_context *ctx)
 	/* name buffer should be allocated before use */
 	err = exfat_alloc_namebuf(nb);
 	if (err)
-		goto unlock;
+		goto out;
 get_new:
+	mutex_lock(&EXFAT_SB(sb)->s_lock);
+
 	if (ei->flags == ALLOC_NO_FAT_CHAIN && cpos >= i_size_read(inode))
 		goto end_of_dir;
 
 	err = exfat_readdir(inode, &cpos, &de);
 	if (err) {
 		/*
-		 * At least we tried to read a sector.  Move cpos to next sector
-		 * position (should be aligned).
+		 * At least we tried to read a sector.
+		 * Move cpos to next sector position (should be aligned).
 		 */
 		if (err == -EIO) {
 			cpos += 1 << (sb->s_blocksize_bits);
@@ -277,16 +285,10 @@ static int exfat_iterate(struct file *file, struct dir_context *ctx)
 		inum = iunique(sb, EXFAT_ROOT_INO);
 	}
 
-	/*
-	 * Before calling dir_emit(), sb_lock should be released.
-	 * Because page fault can occur in dir_emit() when the size
-	 * of buffer given from user is larger than one page size.
-	 */
 	mutex_unlock(&EXFAT_SB(sb)->s_lock);
 	if (!dir_emit(ctx, nb->lfn, strlen(nb->lfn), inum,
 			(de.attr & ATTR_SUBDIR) ? DT_DIR : DT_REG))
-		goto out_unlocked;
-	mutex_lock(&EXFAT_SB(sb)->s_lock);
+		goto out;
 	ctx->pos = cpos;
 	goto get_new;
 
@@ -294,9 +296,8 @@ static int exfat_iterate(struct file *file, struct dir_context *ctx)
 	if (!cpos && fake_offset)
 		cpos = ITER_POS_FILLED_DOTS;
 	ctx->pos = cpos;
-unlock:
 	mutex_unlock(&EXFAT_SB(sb)->s_lock);
-out_unlocked:
+out:
 	/*
 	 * To improve performance, free namebuf after unlock sb_lock.
 	 * If namebuf is not allocated, this function do nothing
@@ -1079,7 +1080,8 @@ int exfat_find_dir_entry(struct super_block *sb, struct exfat_inode_info *ei,
 			if (entry_type == TYPE_EXTEND) {
 				unsigned short entry_uniname[16], unichar;
 
-				if (step != DIRENT_STEP_NAME) {
+				if (step != DIRENT_STEP_NAME ||
+				    name_len >= MAX_NAME_LENGTH) {
 					step = DIRENT_STEP_FILE;
 					continue;
 				}