From: Christoph Hellwig <hch@infradead.org>
To: Nikolai Merinov <n.merinov@inango-systems.com>
Cc: hch@infradead.org, Davidlohr Bueso <dave@stgolabs.net>,
Jens Axboe <axboe@kernel.dk>, Ard Biesheuvel <ardb@kernel.org>,
linux-efi@vger.kernel.org, linux-block@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3] partitions/efi: Fix partition name parsing in GUID partition entry
Date: Tue, 18 Feb 2020 10:53:36 -0800 [thread overview]
Message-ID: <20200218185336.GA14242@infradead.org> (raw)
In-Reply-To: <26f7bd89f212f68b03a4b207e96d8702c9049015.1578910723.git.n.merinov@inango-systems.com>
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@inango-systems.com>
> ---
> 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.
next prev parent reply other threads:[~2020-02-18 18:53 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-24 16:21 [PATCH] partitions/efi: Fix partition name parsing in GUID partition entry Nikolai Merinov
2018-11-25 21:16 ` kbuild test robot
2019-12-24 9:21 ` [PATCH v2] " Nikolai Merinov
2019-12-24 9:51 ` Ard Biesheuvel
2020-01-08 13:39 ` Christoph Hellwig
2020-01-13 10:27 ` [PATCH v3] " Nikolai Merinov
2020-02-18 13:34 ` Nikolai Merinov
2020-02-18 18:53 ` Christoph Hellwig [this message]
2020-02-24 11:38 ` Nikolai Merinov
2020-02-24 17:08 ` hch
2020-03-06 8:43 ` Nikolai Merinov
2020-03-06 9:25 ` Ard Biesheuvel
2020-03-06 10:14 ` Ard Biesheuvel
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