[PATCH v2 1/2] efi_loader: correct reported length in GetNextVariable()

[Punit Agrawal]

Heinrich Schuchardt <xypron.glpk at gmx.de> writes:

> The runtime service GetNextVariable() returns the length of the next
> variable including the closing 0x0000. This length should be in bytes.
>
> Comparing the output of EDK2 and U-Boot shows that this is currently not
> correctly implemented:
>
> EDK2:
> OsIndicationsSupported: 46
> PlatformLang: 26
> PlatformLangCodes: 36
>
> U-Boot:
> OsIndicationsSupported: 23
> PlatformLang: 13
> PlatformLangCodes: 18
>
> Provide correct length in GetNextVariable().
>
> Fixes: d99a87f84b75 ("efi_loader: implement GetNextVariableName()")
> Signed-off-by: Heinrich Schuchardt <xypron.glpk at gmx.de>
> ---
> v2:
> 	correct return value of the initial call too
> ---
>  lib/efi_loader/efi_variable.c | 11 ++++++-----
>  1 file changed, 6 insertions(+), 5 deletions(-)
>
> diff --git a/lib/efi_loader/efi_variable.c b/lib/efi_loader/efi_variable.c
> index 99d2f01f57..3bec2d0d17 100644
> --- a/lib/efi_loader/efi_variable.c
> +++ b/lib/efi_loader/efi_variable.c
> @@ -273,7 +273,8 @@ static efi_status_t parse_uboot_variable(char *variable,
>  					 u32 *attributes)
>  {
>  	char *guid, *name, *end, c;
> -	unsigned long name_len;
> +	size_t name_len;
> +	efi_uintn_t old_variable_name_size;
>  	u16 *p;
>
>  	guid = strchr(variable, '_');
> @@ -289,17 +290,17 @@ static efi_status_t parse_uboot_variable(char *variable,
>  		return EFI_INVALID_PARAMETER;
>
>  	name_len = end - name;
> -	if (*variable_name_size < (name_len + 1)) {
> -		*variable_name_size = name_len + 1;
> +	old_variable_name_size = *variable_name_size;
> +	*variable_name_size = sizeof(u16) * (name_len + 1);
> +	if (old_variable_name_size < *variable_name_size)
>  		return EFI_BUFFER_TOO_SMALL;
> -	}
> +

Ah I see it's fixed in this version. Please ignore my comment on the
previous version.

Thanks,
Punit

>  	end++; /* point to value */
>
>  	/* variable name */
>  	p = variable_name;
>  	utf8_utf16_strncpy(&p, name, name_len);
>  	variable_name[name_len] = 0;
> -	*variable_name_size = name_len + 1;
>
>  	/* guid */
>  	c = *(name - 1);
> --
> 2.25.1