Re: [coreboot] [PATCH] flashrom: Improve coreboot image detection heuristic

[Stefan Reinauer]

Carl-Daniel Hailfinger wrote:
> Improve coreboot image detection heuristic in flashrom. It's not
> absolutely perfect, but the likelihood of this check to fail is
> 0.000000000000000000000000013 (1.3*10^-26) which is good enough for me.

I think at some point we should go to a better concept of doing things,  
but it seems what you are saying is that your code will probably not 
fail on any bios that has been developed to date, as I doubt it is more 
than 10^26 bioses.

Acked-by: Stefan Reinauer
> Signed-off-by: Carl-Daniel Hailfinger
> Index: flashrom-tmp1/layout.c
>
> --- flashrom-tmp1/layout.c	(Revision 3407)
> +++ flashrom-tmp1/layout.c	(Arbeitskopie)
> @@ -21,6 +21,7 @@
>  #include <stdio.h>
>  #include <stdlib.h>
>  #include <string.h>
> +#include <ctype.h>
>  #include <stdint.h>
>  #include "flash.h"
>
> @@ -57,7 +58,18 @@
>    	walk--;
>    }
> if ((*walk) == 0 || ((*walk) & 0x3ff) != 0) {
> /*
> * Check if coreboot last image size is 0 or not a multiple of 1k or
> * bigger than the chip or if the pointers to vendor ID or mainboard ID
> * are outside the image of if the start of ID strings are nonsensical
> * (nonprintable and not \0).
> */
> if ((*walk) == 0 || ((*walk) & 0x3ff) != 0 || *walk > size ||
> *(walk - 1) > size || *(walk - 2) > size ||
> (!isprint((const char *)(bios + size - *(walk - 1))) &&
> ((const char *)(bios + size - *(walk - 1)))) ||
> (!isprint((const char *)(bios + size - *(walk - 2))) &&
> ((const char *)(bios + size - *(walk - 2))))) {
> printf("Flash image seems to be a legacy BIOS. Disabling checks.\n");
> mainboard_vendor = def_name;
> mainboard_part = def_name;