linux-kernel - Re: [PATCH 2/3] x86/microcode/AMD: Make __verify_patch

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20241114125818.GFZzXz6vdhwPdSa4dk@fat_crate.local>
Date: Thu, 14 Nov 2024 13:58:18 +0100
From: Borislav Petkov <bp@...en8.de>
To: Nikolay Borisov <nik.borisov@...e.com>
Cc: x86@...nel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/3] x86/microcode/AMD: Make __verify_patch_size() return
 bool

On Fri, Oct 18, 2024 at 06:51:50PM +0300, Nikolay Borisov wrote:
> The result of that function is in essence boolean, so simplify to return
> the result of the relevant expression. It also makes it follow the
> convetion used by __verify_patch_section(). No functional changes.

convetion used by __verify_patch_section(). No functional changes.
Unknown word [convetion] in commit message.
Suggestions: ['convection', 'convention', 'conversion', 'confection', 'conviction', 'connection', 'confession']

You need a spellchecker. :)

> Signed-off-by: Nikolay Borisov <nik.borisov@...e.com>
> ---
>  arch/x86/kernel/cpu/microcode/amd.c | 11 +++--------
>  1 file changed, 3 insertions(+), 8 deletions(-)
> 
> diff --git a/arch/x86/kernel/cpu/microcode/amd.c b/arch/x86/kernel/cpu/microcode/amd.c
> index 9986cb85c951..37a428b109a2 100644
> --- a/arch/x86/kernel/cpu/microcode/amd.c
> +++ b/arch/x86/kernel/cpu/microcode/amd.c
> @@ -282,7 +282,7 @@ __verify_patch_section(const u8 *buf, size_t buf_size, u32 *sh_psize)
>   * exceed the per-family maximum). @sh_psize is the size read from the section
>   * header.
>   */
> -static unsigned int __verify_patch_size(u32 sh_psize, size_t buf_size)
> +static bool __verify_patch_size(u32 sh_psize, size_t buf_size)
>  {
>  	u8 family = x86_family(bsp_cpuid_1_eax);
>  	u32 max_size;

You missed a spot here for the >= 0x15 families. And I think this is more
readable and more precise what is supposed to be checked here:

---
diff --git a/arch/x86/kernel/cpu/microcode/amd.c b/arch/x86/kernel/cpu/microcode/amd.c
index 8bd79ad63437..0211c62bc4c4 100644
--- a/arch/x86/kernel/cpu/microcode/amd.c
+++ b/arch/x86/kernel/cpu/microcode/amd.c
@@ -289,7 +289,7 @@ static bool __verify_patch_size(u32 sh_psize, size_t buf_size)
 	u32 max_size;
 
 	if (family >= 0x15)
-		return min_t(u32, sh_psize, buf_size);
+		return sh_psize == min_t(u32, sh_psize, buf_size);
 
 #define F1XH_MPB_MAX_SIZE 2048
 #define F14H_MPB_MAX_SIZE 1824
@@ -306,7 +306,7 @@ static bool __verify_patch_size(u32 sh_psize, size_t buf_size)
 		return 0;
 	}
 
-	return sh_psize <= min_t(u32, buf_size, max_size);
+	return sh_psize == min_t(u32, buf_size, max_size);
 }
 
 /*

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette