On Mon, Jan 13, 2020 at 03:27:23PM +0500, Nikolai Merinov wrote:
> GUID partition entry defined to have a partition name as 36 UTF-16LE
> code units. This means that on big-endian platforms ASCII symbols
> would be read with 0xXX00 efi_char16_t character code. In order to
> correctly extract ASCII characters from a partition name field we
> should be converted from 16LE to CPU architecture.
>
> The problem exists on all big endian platforms.
>
> Signed-off-by: Nikolai Merinov <n.merinov@xxxxxxxxxxxxxxxxxx>
> ---
> block/partitions/efi.c | 3 ++-
> block/partitions/efi.h | 2 +-
> include/linux/efi.h | 5 +++++
> 3 files changed, 8 insertions(+), 2 deletions(-)
>
> diff --git a/block/partitions/efi.c b/block/partitions/efi.c
> index db2fef7dfc47..f1d0820de844 100644
> --- a/block/partitions/efi.c
> +++ b/block/partitions/efi.c
> @@ -715,7 +715,8 @@ int efi_partition(struct parsed_partitions *state)
> ARRAY_SIZE(ptes[i].partition_name));
> info->volname[label_max] = 0;
> while (label_count < label_max) {
> - u8 c = ptes[i].partition_name[label_count] & 0xff;
> + u8 c = 0xff & efi_char16le_to_cpu(
> + ptes[i].partition_name[label_count]);
Why are you swapping the order of the comparism to an unusual one here?
> - efi_char16_t partition_name[72 / sizeof (efi_char16_t)];
> + efi_char16le_t partition_name[72 / sizeof(efi_char16le_t)];
> } __packed gpt_entry;
>
> typedef struct _gpt_mbr_record {
> diff --git a/include/linux/efi.h b/include/linux/efi.h
> index aa54586db7a5..47882f2d45db 100644
> --- a/include/linux/efi.h
> +++ b/include/linux/efi.h
> @@ -45,9 +45,14 @@
> typedef unsigned long efi_status_t;
> typedef u8 efi_bool_t;
> typedef u16 efi_char16_t; /* UNICODE character */
> +typedef __le16 efi_char16le_t; /* UTF16-LE */
> +typedef __be16 efi_char16be_t; /* UTF16-BE */
> typedef u64 efi_physical_addr_t;
> typedef void *efi_handle_t;
>
> +#define efi_char16le_to_cpu le16_to_cpu
> +#define efi_char16be_to_cpu be16_to_cpu
I'd rather use plain __le16 and le16_to_cpu here. Also the be
variants seems to be entirely unused.
