Re: [PATCH] fat: Read buffer overflow

[OGAWA Hirofumi]

Roel Kluin <roel.kluin@xxxxxxxxx> writes:

> If len is less or equal to 0, this results in a read of s[-1].
>
> Signed-off-by: Roel Kluin <roel.kluin@xxxxxxxxx>
> ---
> diff --git a/fs/fat/namei_vfat.c b/fs/fat/namei_vfat.c
> index 6f27853..114ff6d 100644
> --- a/fs/fat/namei_vfat.c
> +++ b/fs/fat/namei_vfat.c
> @@ -202,6 +202,9 @@ static inline int vfat_is_used_badchars(const wchar_t *s, int len)
>  {
>  	int i;
>  
> +	if (len <= 0)
> +		return -EINVAL;
> +
>  	for (i = 0; i < len; i++)
>  		if (vfat_bad_char(s[i]))
>  			return -EINVAL;

Um..., what case is this possible? vfat_add_entry() checks (len == 0).
And if xlate_to_uni() couldn't convert name, it should return the error.

Thanks.
-- 
OGAWA Hirofumi <hirofumi@xxxxxxxxxxxxxxxxxx>
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