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From: Matt Fleming <matt-mF/unelCI9GS6iBeEJttW/XRex20P6io@public.gmane.org>
To: Ard Biesheuvel <ard.biesheuvel-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
Cc: "linux-efi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org"
	<linux-efi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
	"linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org"
	<linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org>,
	Mark Rutland <mark.rutland-5wv7dgnIgG8@public.gmane.org>,
	Russell King - ARM Linux
	<linux-lFZ/pmaqli7XmaaqVzeoHQ@public.gmane.org>,
	Catalin Marinas <catalin.marinas-5wv7dgnIgG8@public.gmane.org>,
	Will Deacon <will.deacon-5wv7dgnIgG8@public.gmane.org>,
	Leif Lindholm
	<leif.lindholm-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>,
	Peter Jones <pjones-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
	"Prakhya,
	Sai Praneeth"
	<sai.praneeth.prakhya-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
Subject: Re: [PATCH v2 4/5] efi: implement generic support for the Memory Attributes table
Date: Tue, 12 Apr 2016 20:57:27 +0100	[thread overview]
Message-ID: <20160412195727.GG2829@codeblueprint.co.uk> (raw)
In-Reply-To: <CAKv+Gu-TMb0MTnzXXjczvxaWvZphu7M1-MMdjCrZ7A2CvCc2WQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>

On Mon, 11 Apr, at 04:09:11PM, Ard Biesheuvel wrote:
> 
> The spec does not actually mandate that, and I do know that the
> Tianocore code deliberately uses a larger value for desc_size in
> GetMemoryMap() to catch inadvertent uses of sizeof(). I am not sure if
> the memory attribute table code does the same, and it seems dangerous
> to assume that to be the case in general.
 
The spec may not mandate that, but this code will explode horribly if
efi_memory_desc_t does not accurately describe the entries in either
the EFI Memory Attributes table or the EFI memory map.

How do we ensure that doing,

static bool entry_is_valid(...)
{
	*out = *in;
	...

keeps working? Are we using the table version to guarantee that?

WARNING: multiple messages have this Message-ID (diff)
From: matt@codeblueprint.co.uk (Matt Fleming)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2 4/5] efi: implement generic support for the Memory Attributes table
Date: Tue, 12 Apr 2016 20:57:27 +0100	[thread overview]
Message-ID: <20160412195727.GG2829@codeblueprint.co.uk> (raw)
In-Reply-To: <CAKv+Gu-TMb0MTnzXXjczvxaWvZphu7M1-MMdjCrZ7A2CvCc2WQ@mail.gmail.com>

On Mon, 11 Apr, at 04:09:11PM, Ard Biesheuvel wrote:
> 
> The spec does not actually mandate that, and I do know that the
> Tianocore code deliberately uses a larger value for desc_size in
> GetMemoryMap() to catch inadvertent uses of sizeof(). I am not sure if
> the memory attribute table code does the same, and it seems dangerous
> to assume that to be the case in general.
 
The spec may not mandate that, but this code will explode horribly if
efi_memory_desc_t does not accurately describe the entries in either
the EFI Memory Attributes table or the EFI memory map.

How do we ensure that doing,

static bool entry_is_valid(...)
{
	*out = *in;
	...

keeps working? Are we using the table version to guarantee that?

  parent reply	other threads:[~2016-04-12 19:57 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-03-30 16:38 [PATCH v2 0/5] UEFI: memory attribute table support Ard Biesheuvel
2016-03-30 16:38 ` Ard Biesheuvel
     [not found] ` <1459355933-13529-1-git-send-email-ard.biesheuvel-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
2016-03-30 16:38   ` [PATCH v2 1/5] ARM: efi: apply strict permissons for UEFI Runtime Services regions Ard Biesheuvel
2016-03-30 16:38     ` Ard Biesheuvel
2016-03-30 16:38   ` [PATCH v2 2/5] arm64: " Ard Biesheuvel
2016-03-30 16:38     ` Ard Biesheuvel
     [not found]     ` <1459355933-13529-3-git-send-email-ard.biesheuvel-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
2016-05-18  0:40       ` Shanker Donthineni
2016-05-18  0:40         ` Shanker Donthineni
     [not found]         ` <573BB9FE.7050008-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>
2016-05-18  6:18           ` Ard Biesheuvel
2016-05-18  6:18             ` Ard Biesheuvel
     [not found]             ` <CAKv+Gu-Tam+QiXc_f0e+x8hNc4rxP_-59NdaCHkF9h=4Rd+XeA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2016-05-18 13:06               ` Shanker Donthineni
2016-05-18 13:06                 ` Shanker Donthineni
     [not found]                 ` <573C68DA.8080009-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>
2016-05-18 13:08                   ` Ard Biesheuvel
2016-05-18 13:08                     ` Ard Biesheuvel
2016-03-30 16:38   ` [PATCH v2 3/5] efi: add support for the EFI_MEMORY_ATTRIBUTES_TABLE config table Ard Biesheuvel
2016-03-30 16:38     ` Ard Biesheuvel
2016-03-30 16:38   ` [PATCH v2 4/5] efi: implement generic support for the Memory Attributes table Ard Biesheuvel
2016-03-30 16:38     ` Ard Biesheuvel
     [not found]     ` <1459355933-13529-5-git-send-email-ard.biesheuvel-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
2016-04-01 12:36       ` Ard Biesheuvel
2016-04-01 12:36         ` Ard Biesheuvel
2016-04-08 15:56       ` Matt Fleming
2016-04-08 15:56         ` Matt Fleming
     [not found]         ` <20160408155608.GQ2701-mF/unelCI9GS6iBeEJttW/XRex20P6io@public.gmane.org>
2016-04-11 14:09           ` Ard Biesheuvel
2016-04-11 14:09             ` Ard Biesheuvel
     [not found]             ` <CAKv+Gu-TMb0MTnzXXjczvxaWvZphu7M1-MMdjCrZ7A2CvCc2WQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2016-04-12 19:57               ` Matt Fleming [this message]
2016-04-12 19:57                 ` Matt Fleming
     [not found]                 ` <20160412195727.GG2829-mF/unelCI9GS6iBeEJttW/XRex20P6io@public.gmane.org>
2016-04-13  8:29                   ` Ard Biesheuvel
2016-04-13  8:29                     ` Ard Biesheuvel
     [not found]                     ` <CAKv+Gu-bLN16YKei3togReQBNo+ScQVf7ek2NJEZAEyii2JEcw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2016-04-13 10:24                       ` Matt Fleming
2016-04-13 10:24                         ` Matt Fleming
     [not found]                         ` <20160413102408.GL2829-mF/unelCI9GS6iBeEJttW/XRex20P6io@public.gmane.org>
2016-04-13 10:24                           ` Ard Biesheuvel
2016-04-13 10:24                             ` Ard Biesheuvel
2016-03-30 16:38   ` [PATCH v2 5/5] arm*: efi: take the Memory Attributes table into account Ard Biesheuvel
2016-03-30 16:38     ` Ard Biesheuvel

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