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From: Borislav Petkov <bp@alien8.de>
To: "Maciej S. Szmigiero" <mail@maciej.szmigiero.name>
Cc: Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
	x86@kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v5 6/6] x86/microcode/AMD: Check the equivalence table size when scanning it
Date: Mon, 30 Apr 2018 11:05:42 +0200	[thread overview]
Message-ID: <20180430090542.GD6509@pd.tnic> (raw)
In-Reply-To: <68fade9fda9e63c0722052abecaf4ed0c360beeb.1524515406.git.mail@maciej.szmigiero.name>

On Mon, Apr 23, 2018 at 11:34:11PM +0200, Maciej S. Szmigiero wrote:
> Currently, the code scanning the CPU equivalence table read from a
> microcode container file assumes that it actually contains a terminating
> zero entry.
> Let's check also the size of this table to make sure that we don't read
> past it in case it actually doesn't.

...

> @@ -697,6 +706,7 @@ static unsigned int install_equiv_cpu_table(const u8 *buf, size_t buf_size)
>  	}
>  
>  	memcpy(equiv_cpu_table, buf + CONTAINER_HDR_SZ, equiv_tbl_len);
> +	equiv_cpu_table_entries = equiv_tbl_len / sizeof(struct equiv_cpu_entry);
>  
>  	return equiv_tbl_len;

Instead of adding yet another global var which needs handling too,
and touching so many places, just do all checks and preparations in
install_equiv_cpu_table() so that the rest of the code can get what it
expects: terminating zero entry and proper size.

Thx.

-- 
Regards/Gruss,
    Boris.

Good mailing practices for 400: avoid top-posting and trim the reply.

      reply	other threads:[~2018-04-30  9:06 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-23 21:34 [PATCH v5 0/6] x86/microcode/AMD: Check microcode file sanity before loading it Maciej S. Szmigiero
2018-04-23 21:34 ` [PATCH v5 1/6] x86/microcode/AMD: Subtract SECTION_HDR_SIZE from file leftover length Maciej S. Szmigiero
2018-04-23 21:34 ` [PATCH v5 2/6] x86/microcode/AMD: Add microcode container data checking functions Maciej S. Szmigiero
2018-04-30  9:04   ` Borislav Petkov
2018-04-30 22:27     ` Maciej S. Szmigiero
2018-05-01  8:18       ` Borislav Petkov
2018-05-01 16:19         ` Maciej S. Szmigiero
2018-04-23 21:34 ` [PATCH v5 3/6] x86/microcode/AMD: Check microcode container data in the early loader Maciej S. Szmigiero
2018-04-30  9:05   ` Borislav Petkov
2018-04-30 22:27     ` Maciej S. Szmigiero
2018-05-01  8:44       ` Borislav Petkov
2018-04-23 21:34 ` [PATCH v5 4/6] x86/microcode/AMD: Check microcode container data in the late loader Maciej S. Szmigiero
2018-04-30  9:05   ` Borislav Petkov
2018-04-30 22:27     ` Maciej S. Szmigiero
2018-05-01  8:43       ` Borislav Petkov
2018-05-01 16:19         ` Maciej S. Szmigiero
2018-05-01 20:03           ` Borislav Petkov
2018-05-02  0:47             ` Maciej S. Szmigiero
2018-05-03 10:01               ` Borislav Petkov
2018-05-03 23:26                 ` Maciej S. Szmigiero
2018-05-07 16:35                   ` Borislav Petkov
2018-04-23 21:34 ` [PATCH v5 5/6] x86/microcode/AMD: Add a reminder about PATCH_MAX_SIZE macro Maciej S. Szmigiero
2018-04-23 21:34 ` [PATCH v5 6/6] x86/microcode/AMD: Check the equivalence table size when scanning it Maciej S. Szmigiero
2018-04-30  9:05   ` Borislav Petkov [this message]

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