[PATCH V2] efi_loader: loosen buffer parameter check in efi_file_read_int

[Heinrich Schuchardt]

On 28.04.21 15:54, Peng Fan (OSS) wrote:
> From: Peng Fan <peng.fan at nxp.com>
>
> This is same issue as https://bugzilla.redhat.com/show_bug.cgi?id=1733817,
> but that fix was wrongly partial reverted.
>
> When reading a directory, EFI_BUFFER_TOO_SMALL should be returned when
> the supplied buffer is too small, so a use-case is to call
> EFI_FILE_PROTOCOL.Read() with *buffer_size=0 and buffer=NULL to
> obtain the needed size before doing the actual read.
>
> So remove the check only for directory reading, file reading already
> do the check by itself.
>
> Fixes: db12f518edb0("efi_loader: implement non-blocking file services")
> Cc: Heinrich Schuchardt <xypron.glpk at gmx.de>
> Cc: Stefan Sørensen <stefan.sorensen at spectralink.com>
> Tested-by: Peter Robinson <pbrobinson at gmail.com>
> Signed-off-by: Peng Fan <peng.fan at nxp.com>

Reviewed-by: Heinrich Schuchardt <xypron.glpk at gmx.de>

> ---
>
> V2:
>  Update commit log Per Heinrich's comments.
>  Add T-b tag
>
>  lib/efi_loader/efi_file.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/lib/efi_loader/efi_file.c b/lib/efi_loader/efi_file.c
> index 204105e25a..6b3f5962be 100644
> --- a/lib/efi_loader/efi_file.c
> +++ b/lib/efi_loader/efi_file.c
> @@ -554,7 +554,7 @@ static efi_status_t efi_file_read_int(struct efi_file_handle *this,
>  	efi_status_t ret = EFI_SUCCESS;
>  	u64 bs;
>
> -	if (!this || !buffer_size || !buffer)
> +	if (!this || !buffer_size)
>  		return EFI_INVALID_PARAMETER;
>
>  	bs = *buffer_size;
>