[v2] hfsplus: don't use BUG_ON() in hfsplus_create_attributes_file()

[PATCH v2] hfsplus: don't use BUG_ON() in hfsplus_create_attributes_file()

Posted by Tetsuo Handa 2 months, 3 weeks ago

When the volume header contains erroneous values that do not reflect
the actual state of the filesystem, hfsplus_fill_super() assumes that
the attributes file is not yet created, which later results in hitting
BUG_ON() when hfsplus_create_attributes_file() is called. Replace this
BUG_ON() with -EIO error with a message to suggest running fsck tool.

Reported-by: syzbot <syzbot+1107451c16b9eb9d29e6@syzkaller.appspotmail.com>
Closes: https://syzkaller.appspot.com/bug?extid=1107451c16b9eb9d29e6
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
---
 fs/hfsplus/xattr.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/fs/hfsplus/xattr.c b/fs/hfsplus/xattr.c
index 9a1a93e3888b..18dc3d254d21 100644
--- a/fs/hfsplus/xattr.c
+++ b/fs/hfsplus/xattr.c
@@ -172,7 +172,11 @@ static int hfsplus_create_attributes_file(struct super_block *sb)
 		return PTR_ERR(attr_file);
 	}
 
-	BUG_ON(i_size_read(attr_file) != 0);
+	if (i_size_read(attr_file) != 0) {
+		err = -EIO;
+		pr_err("detected inconsistent attributes file, running fsck.hfsplus is recommended.\n");
+		goto end_attr_file_creation;
+	}
 
 	hip = HFSPLUS_I(attr_file);
 
-- 
2.50.1

Re: [PATCH v2] hfsplus: don't use BUG_ON() in hfsplus_create_attributes_file()

Posted by Viacheslav Dubeyko 2 months, 3 weeks ago

On Tue, 2025-07-15 at 14:17 +0900, Tetsuo Handa wrote:
> When the volume header contains erroneous values that do not reflect
> the actual state of the filesystem, hfsplus_fill_super() assumes that
> the attributes file is not yet created, which later results in hitting
> BUG_ON() when hfsplus_create_attributes_file() is called. Replace this
> BUG_ON() with -EIO error with a message to suggest running fsck tool.
> 
> Reported-by: syzbot <syzbot+1107451c16b9eb9d29e6@syzkaller.appspotmail.com>
> Closes: https://syzkaller.appspot.com/bug?extid=1107451c16b9eb9d29e6  
> Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
> ---
>  fs/hfsplus/xattr.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/hfsplus/xattr.c b/fs/hfsplus/xattr.c
> index 9a1a93e3888b..18dc3d254d21 100644
> --- a/fs/hfsplus/xattr.c
> +++ b/fs/hfsplus/xattr.c
> @@ -172,7 +172,11 @@ static int hfsplus_create_attributes_file(struct super_block *sb)
>  		return PTR_ERR(attr_file);
>  	}
>  
> -	BUG_ON(i_size_read(attr_file) != 0);
> +	if (i_size_read(attr_file) != 0) {
> +		err = -EIO;
> +		pr_err("detected inconsistent attributes file, running fsck.hfsplus is recommended.\n");
> +		goto end_attr_file_creation;
> +	}
>  
>  	hip = HFSPLUS_I(attr_file);
>  

Looks good!

Reviewed-by: Viacheslav Dubeyko <slava@dubeyko.com>

Thanks,
Slava.