[PATCH] firmware: dmi_scan: Only honor end-of-table for 64-bit tables

[PATCH] firmware: dmi_scan: Only honor end-of-table for 64-bit tables

[Jean Delvare]

From: Jean Delvare <jdelvare@suse.de>
Subject: firmware: dmi_scan: Only honor end-of-table for 64-bit tables

A 32-bit entry point to a DMI table says how many structures the table
contains. The SMBIOS specification explicitly says that end-of-table
markers should be ignored if they are not actually at the end of the
DMI table. So only honor the end-of-table marker for tables accessed
through 64-bit entry points, as they do not specify a structure count.

Fixes: fc43026278 ("dmi: add support for SMBIOS 3.0 64-bit entry point")
Signed-off-by: Jean Delvare <jdelvare@suse.de>
Cc: Leif Lindholm <leif.lindholm@linaro.org>
Cc: Matt Fleming <matt.fleming@intel.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 drivers/firmware/dmi_scan.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- linux-4.1-rc1.orig/drivers/firmware/dmi_scan.c	2015-04-28 16:39:00.845282262 +0200
+++ linux-4.1-rc1/drivers/firmware/dmi_scan.c	2015-04-28 16:47:35.092644748 +0200
@@ -111,7 +111,7 @@ static void dmi_table(u8 *buf,
 		/*
 		 * 7.45 End-of-Table (Type 127) [SMBIOS reference spec v3.0.0]
 		 */
-		if (dm->type == DMI_ENTRY_END_OF_TABLE)
+		if (!dmi_num && dm->type == DMI_ENTRY_END_OF_TABLE)
 			break;
 
 		data += 2;


-- 
Jean Delvare
SUSE L3 Support

Re: [PATCH] firmware: dmi_scan: Only honor end-of-table for 64-bit tables

[Ard Biesheuvel]

On 28 April 2015 at 20:41, Jean Delvare <jdelvare@suse.de> wrote:
> From: Jean Delvare <jdelvare@suse.de>
> Subject: firmware: dmi_scan: Only honor end-of-table for 64-bit tables
>
> A 32-bit entry point to a DMI table says how many structures the table
> contains. The SMBIOS specification explicitly says that end-of-table
> markers should be ignored if they are not actually at the end of the
> DMI table. So only honor the end-of-table marker for tables accessed
> through 64-bit entry points, as they do not specify a structure count.
>
> Fixes: fc43026278 ("dmi: add support for SMBIOS 3.0 64-bit entry point")
> Signed-off-by: Jean Delvare <jdelvare@suse.de>
> Cc: Leif Lindholm <leif.lindholm@linaro.org>
> Cc: Matt Fleming <matt.fleming@intel.com>
> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> ---
>  drivers/firmware/dmi_scan.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> --- linux-4.1-rc1.orig/drivers/firmware/dmi_scan.c      2015-04-28 16:39:00.845282262 +0200
> +++ linux-4.1-rc1/drivers/firmware/dmi_scan.c   2015-04-28 16:47:35.092644748 +0200
> @@ -111,7 +111,7 @@ static void dmi_table(u8 *buf,
>                 /*
>                  * 7.45 End-of-Table (Type 127) [SMBIOS reference spec v3.0.0]

I wrote this comment under the assumption that type #127 was new in
v3, but apparently it is not.
Since you are changing the test below into something non-trivial,
could we perhaps update the comment to explain better what goes on
here?

>                  */
> -               if (dm->type == DMI_ENTRY_END_OF_TABLE)
> +               if (!dmi_num && dm->type == DMI_ENTRY_END_OF_TABLE)
>                         break;
>
>                 data += 2;
>

Re: [PATCH] firmware: dmi_scan: Only honor end-of-table for 64-bit tables

[Jean Delvare]

Hi Ard,

Le Thursday 30 April 2015 à 12:37 +0200, Ard Biesheuvel a écrit :
> On 28 April 2015 at 20:41, Jean Delvare <jdelvare@suse.de> wrote:
> > From: Jean Delvare <jdelvare@suse.de>
> > Subject: firmware: dmi_scan: Only honor end-of-table for 64-bit tables
> >
> > A 32-bit entry point to a DMI table says how many structures the table
> > contains. The SMBIOS specification explicitly says that end-of-table
> > markers should be ignored if they are not actually at the end of the
> > DMI table. So only honor the end-of-table marker for tables accessed
> > through 64-bit entry points, as they do not specify a structure count.
> >
> > Fixes: fc43026278 ("dmi: add support for SMBIOS 3.0 64-bit entry point")
> > Signed-off-by: Jean Delvare <jdelvare@suse.de>
> > Cc: Leif Lindholm <leif.lindholm@linaro.org>
> > Cc: Matt Fleming <matt.fleming@intel.com>
> > Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> > ---
> >  drivers/firmware/dmi_scan.c |    2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > --- linux-4.1-rc1.orig/drivers/firmware/dmi_scan.c      2015-04-28 16:39:00.845282262 +0200
> > +++ linux-4.1-rc1/drivers/firmware/dmi_scan.c   2015-04-28 16:47:35.092644748 +0200
> > @@ -111,7 +111,7 @@ static void dmi_table(u8 *buf,
> >                 /*
> >                  * 7.45 End-of-Table (Type 127) [SMBIOS reference spec v3.0.0]
> 
> I wrote this comment under the assumption that type #127 was new in
> v3, but apparently it is not.
> Since you are changing the test below into something non-trivial,
> could we perhaps update the comment to explain better what goes on
> here?

Good idea, thanks for suggesting. Version 2 of the patch is coming.

> >                  */
> > -               if (dm->type == DMI_ENTRY_END_OF_TABLE)
> > +               if (!dmi_num && dm->type == DMI_ENTRY_END_OF_TABLE)
> >                         break;
> >
> >                 data += 2;
> >


-- 
Jean Delvare
SUSE L3 Support