[PATCH] fwts:dmicheck: replace memcpy with byte copy for SMBIOS 3.0 table

[wufan]

This is a real issue. Without the patch the dmicheck test will fail with
segfault:

ubuntu at ubuntu:~/fwts/src$ sudo ./fwts dmicheck -
Results generated by fwts: Version V16.11.00 (2016-11-10 08:39:49).

Some of this work - Copyright (c) 1999 - 2016, Intel Corp. All rights
reserved.
Some of this work - Copyright (c) 2010 - 2016, Canonical.
Some of this work - Copyright (c) 2016 IBM.

This test run on 28/11/16 at 18:56:40 on host Linux ubuntu 4.7.0 #2 SMP Sun
Oct 16 14:57:06 MDT 2016 aarch64.

Command: "fwts dmicheck -".
Running tests: dmicheck.

dmicheck: DMI/SMBIOS table tests.
----------------------------------------------------------------------------
----------------------------------------------------
Test 1 of 3: Find and test SMBIOS Table Entry Points.
This test tries to find and sanity check the SMBIOS data structures.
PASSED: Test 1, Found SMBIOS30 Table Entry Point at 0x43fffb0000
SMBIOS30 Entry Point Structure:
  Anchor String          : _SM3_
  Checksum               : 0x9b
  Entry Point Length     : 0x18
  Major Version          : 0x03
  Minor Version          : 0x00
  Docrev                 : 0x00
  Entry Point Revision   : 0x01
  Reserved               : 0x00
  Table maximum size     : 0x0000263d
  Table address          : 0x00000043f9190000

PASSED: Test 1, SMBIOS30 Table Entry Point Checksum is valid.
PASSED: Test 1, SMBIOS30 Table Entry Point Length is valid.

Caught SIGNAL 11 (Segmentation fault), aborting.
Backtrace:
0x0000ffffac10ff84 /home/ubuntu/fwts/src/lib/src/.libs/libfwts.so.1(+0xff84)


Fan


-----Original Message-----
From: Colin Ian King [mailto:colin.king at canonical.com] 
Sent: Monday, November 28, 2016 1:08 PM
To: wufan <wufan at codeaurora.org>; fwts-devel at lists.ubuntu.com
Subject: Re: [PATCH] fwts:dmicheck: replace memcpy with byte copy for SMBIOS
3.0 table

On 28/11/16 18:26, wufan wrote:
> From 00cae446405d4d856fbd56222f835c207d18d8e8 Mon Sep 17 00:00:00 2001
> 
> From: Fan Wu <wufan at codeaurora.org>
> 
> Date: Thu, 3 Nov 2016 14:03:40 -0600
> 
> Subject: [PATCH] fwts:dmicheck: replace memcpy with byte copy for 
> SMBIOS 3.0
> 
> table
> 
>  
> 
> Mapping of SMBIOS 3.0 table in AARCH64 platforms through /dev/mem
> 
> has the memory tagged as device memory, and memcpy could trigger
> 
> alignment fault if the SMBIOS table is of odd size. The fix is to
> 
> replace memcpy with byte copy.
> 
>  
> 
> Change-Id: I52a5be2fedcd057fdd5e510ff090e4129f128221
> 
> ---
> 
> src/dmi/dmicheck/dmicheck.c | 7 +++++--
> 
> 1 file changed, 5 insertions(+), 2 deletions(-)
> 
>  
> 
> diff --git a/src/dmi/dmicheck/dmicheck.c b/src/dmi/dmicheck/dmicheck.c
> 
> index 1934ebe..98db76b 100644
> 
> --- a/src/dmi/dmicheck/dmicheck.c
> 
> +++ b/src/dmi/dmicheck/dmicheck.c
> 
> @@ -370,8 +370,11 @@ static void* dmi_table_smbios30(fwts_framework 
> *fw, fwts_smbios30_entry *entry)
> 
>         mem = fwts_mmap(addr, length);
> 
>         if (mem != FWTS_MAP_FAILED) {
> 
>                 table = malloc(length);
> 
> -               if (table)
> 
> -                       memcpy(table, mem, length);
> 
> +               if (table) {
> 
> +                       size_t i = length;
> 
> +                       while (i--)
> 
> +                               ((uint8_t*)table)[i] = 
> + ((uint8_t*)mem)[i];
> 
> +               }
> 
>                 (void)fwts_munmap(mem, length);
> 
>                 return table;
> 
>         }
> 
> --
> 
> 1.8.2.1
> 
Is this a hypothetical issue or does it fix an observed issue with
non-aligned SMBIOS tables?

Colin