diff mbox series

[v3] partitions/efi: Fix partition name parsing in GUID partition entry

Message ID 26f7bd89f212f68b03a4b207e96d8702c9049015.1578910723.git.n.merinov@inango-systems.com
State New, archived
Headers show
Series [v3] partitions/efi: Fix partition name parsing in GUID partition entry | expand

Commit Message

Nikolai Merinov Jan. 13, 2020, 10:27 a.m. UTC
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(-)

Comments

Nikolai Merinov Feb. 18, 2020, 1:34 p.m. UTC | #1
Hello,

Did you have a time to look at this patch? Should I make any modification? 

Regards,
Nikolai

----- Original Message -----
> From: "n merinov" <n.merinov@inango-systems.com>
> To: 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"
> <linux-kernel@vger.kernel.org>
> Cc: "n merinov" <n.merinov@inango-systems.com>
> Sent: Monday, January 13, 2020 3:27:23 PM
> Subject: [PATCH v3] partitions/efi: Fix partition name parsing in GUID partition entry

> 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]);
> 			if (c && !isprint(c))
> 				c = '!';
> 			info->volname[label_count] = c;
> diff --git a/block/partitions/efi.h b/block/partitions/efi.h
> index 3e8576157575..4d4cae0bb79e 100644
> --- a/block/partitions/efi.h
> +++ b/block/partitions/efi.h
> @@ -88,7 +88,7 @@ typedef struct _gpt_entry {
> 	__le64 starting_lba;
> 	__le64 ending_lba;
> 	gpt_entry_attributes attributes;
> -	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
> +
> /*
>  * The UEFI spec and EDK2 reference implementation both define EFI_GUID as
>  * struct { u32 a; u16; b; u16 c; u8 d[8]; }; and so the implied alignment
> --
> 2.17.1
Christoph Hellwig Feb. 18, 2020, 6:53 p.m. UTC | #2
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.
Nikolai Merinov Feb. 24, 2020, 11:38 a.m. UTC | #3
Hi Christoph, 

> I'd rather use plain __le16 and le16_to_cpu here. Also the be 
> variants seems to be entirely unused. 

Looks like I misunderstood your comment from https://patchwork.kernel.org/patch/11309223/: 

> Please add a an efi_char_from_cpu or similarly named helper 
> to encapsulate this logic. 

The "le16_to_cpu(ptes[i].partition_name[label_count])" call is the 
full implementation of the "efi_char_from_cpu" logic. Do you want 
to encapsulate "utf16_le_to_7bit_string" logic entirely like in
the attached version?

Regards,
Nikolai
Christoph Hellwig Feb. 24, 2020, 5:08 p.m. UTC | #4
On Mon, Feb 24, 2020 at 01:38:39PM +0200, Nikolai Merinov wrote:
> Hi Christoph, 
> 
> > I'd rather use plain __le16 and le16_to_cpu here. Also the be 
> > variants seems to be entirely unused. 
> 
> Looks like I misunderstood your comment from https://patchwork.kernel.org/patch/11309223/: 
> 
> > Please add a an efi_char_from_cpu or similarly named helper 
> > to encapsulate this logic. 
> 
> The "le16_to_cpu(ptes[i].partition_name[label_count])" call is the 
> full implementation of the "efi_char_from_cpu" logic. Do you want 
> to encapsulate "utf16_le_to_7bit_string" logic entirely like in
> the attached version?

I think I though of just the inner loop, but your new version looks even
better, so:

Reviewed-by: Christoph Hellwig <hch@lst.de>
Nikolai Merinov March 6, 2020, 8:43 a.m. UTC | #5
Hi Christoph,

Should I perform any other steps in order to get this change in the master?

Regards,
Nikolai

----- Original Message -----
> From: "hch" <hch@infradead.org>
> To: "n merinov" <n.merinov@inango-systems.com>
> Cc: "hch" <hch@infradead.org>, "Davidlohr Bueso" <dave@stgolabs.net>, "Jens Axboe" <axboe@kernel.dk>, "Ard Biesheuvel"
> <ardb@kernel.org>, "linux-efi" <linux-efi@vger.kernel.org>, "linux-block" <linux-block@vger.kernel.org>, "linux-kernel"
> <linux-kernel@vger.kernel.org>
> Sent: Monday, February 24, 2020 10:08:13 PM
> Subject: Re: [PATCH v3] partitions/efi: Fix partition name parsing in GUID partition entry

> On Mon, Feb 24, 2020 at 01:38:39PM +0200, Nikolai Merinov wrote:
>> Hi Christoph,
>> 
>> > I'd rather use plain __le16 and le16_to_cpu here. Also the be
>> > variants seems to be entirely unused.
>> 
>> Looks like I misunderstood your comment from
>> https://patchwork.kernel.org/patch/11309223/:
>> 
>> > Please add a an efi_char_from_cpu or similarly named helper
>> > to encapsulate this logic.
>> 
>> The "le16_to_cpu(ptes[i].partition_name[label_count])" call is the
>> full implementation of the "efi_char_from_cpu" logic. Do you want
>> to encapsulate "utf16_le_to_7bit_string" logic entirely like in
>> the attached version?
> 
> I think I though of just the inner loop, but your new version looks even
> better, so:
> 
> Reviewed-by: Christoph Hellwig <hch@lst.de>
Ard Biesheuvel March 6, 2020, 9:25 a.m. UTC | #6
On Fri, 6 Mar 2020 at 09:43, Nikolai Merinov
<n.merinov@inango-systems.com> wrote:
>
> Hi Christoph,
>
> Should I perform any other steps in order to get this change in the master?
>

I can take it via the EFI tree with an ack from Dave.


>
> ----- Original Message -----
> > From: "hch" <hch@infradead.org>
> > To: "n merinov" <n.merinov@inango-systems.com>
> > Cc: "hch" <hch@infradead.org>, "Davidlohr Bueso" <dave@stgolabs.net>, "Jens Axboe" <axboe@kernel.dk>, "Ard Biesheuvel"
> > <ardb@kernel.org>, "linux-efi" <linux-efi@vger.kernel.org>, "linux-block" <linux-block@vger.kernel.org>, "linux-kernel"
> > <linux-kernel@vger.kernel.org>
> > Sent: Monday, February 24, 2020 10:08:13 PM
> > Subject: Re: [PATCH v3] partitions/efi: Fix partition name parsing in GUID partition entry
>
> > On Mon, Feb 24, 2020 at 01:38:39PM +0200, Nikolai Merinov wrote:
> >> Hi Christoph,
> >>
> >> > I'd rather use plain __le16 and le16_to_cpu here. Also the be
> >> > variants seems to be entirely unused.
> >>
> >> Looks like I misunderstood your comment from
> >> https://patchwork.kernel.org/patch/11309223/:
> >>
> >> > Please add a an efi_char_from_cpu or similarly named helper
> >> > to encapsulate this logic.
> >>
> >> The "le16_to_cpu(ptes[i].partition_name[label_count])" call is the
> >> full implementation of the "efi_char_from_cpu" logic. Do you want
> >> to encapsulate "utf16_le_to_7bit_string" logic entirely like in
> >> the attached version?
> >
> > I think I though of just the inner loop, but your new version looks even
> > better, so:
> >
> > Reviewed-by: Christoph Hellwig <hch@lst.de>
Ard Biesheuvel March 6, 2020, 10:14 a.m. UTC | #7
On Fri, 6 Mar 2020 at 10:25, Ard Biesheuvel <ardb@kernel.org> wrote:
>
> On Fri, 6 Mar 2020 at 09:43, Nikolai Merinov
> <n.merinov@inango-systems.com> wrote:
> >
> > Hi Christoph,
> >
> > Should I perform any other steps in order to get this change in the master?
> >
>
> I can take it via the EFI tree with an ack from Dave.
>

... or actually, I'm sure Dave is fine with it, so I'll just queue it
in efi/next directly (with Christoph's ack)

>
> >
> > ----- Original Message -----
> > > From: "hch" <hch@infradead.org>
> > > To: "n merinov" <n.merinov@inango-systems.com>
> > > Cc: "hch" <hch@infradead.org>, "Davidlohr Bueso" <dave@stgolabs.net>, "Jens Axboe" <axboe@kernel.dk>, "Ard Biesheuvel"
> > > <ardb@kernel.org>, "linux-efi" <linux-efi@vger.kernel.org>, "linux-block" <linux-block@vger.kernel.org>, "linux-kernel"
> > > <linux-kernel@vger.kernel.org>
> > > Sent: Monday, February 24, 2020 10:08:13 PM
> > > Subject: Re: [PATCH v3] partitions/efi: Fix partition name parsing in GUID partition entry
> >
> > > On Mon, Feb 24, 2020 at 01:38:39PM +0200, Nikolai Merinov wrote:
> > >> Hi Christoph,
> > >>
> > >> > I'd rather use plain __le16 and le16_to_cpu here. Also the be
> > >> > variants seems to be entirely unused.
> > >>
> > >> Looks like I misunderstood your comment from
> > >> https://patchwork.kernel.org/patch/11309223/:
> > >>
> > >> > Please add a an efi_char_from_cpu or similarly named helper
> > >> > to encapsulate this logic.
> > >>
> > >> The "le16_to_cpu(ptes[i].partition_name[label_count])" call is the
> > >> full implementation of the "efi_char_from_cpu" logic. Do you want
> > >> to encapsulate "utf16_le_to_7bit_string" logic entirely like in
> > >> the attached version?
> > >
> > > I think I though of just the inner loop, but your new version looks even
> > > better, so:
> > >
> > > Reviewed-by: Christoph Hellwig <hch@lst.de>
diff mbox series

Patch

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]);
 			if (c && !isprint(c))
 				c = '!';
 			info->volname[label_count] = c;
diff --git a/block/partitions/efi.h b/block/partitions/efi.h
index 3e8576157575..4d4cae0bb79e 100644
--- a/block/partitions/efi.h
+++ b/block/partitions/efi.h
@@ -88,7 +88,7 @@  typedef struct _gpt_entry {
 	__le64 starting_lba;
 	__le64 ending_lba;
 	gpt_entry_attributes attributes;
-	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
+
 /*
  * The UEFI spec and EDK2 reference implementation both define EFI_GUID as
  * struct { u32 a; u16; b; u16 c; u8 d[8]; }; and so the implied alignment