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.

Acked-by: Stefan Reinauer <[EMAIL PROTECTED]>

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.

Signed-off-by: Carl-Daniel Hailfinger <[EMAIL PROTECTED]>

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"

                walk--;
        }

+       /*
+        * 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;

@@ -57,7 +58,18 @@ - if ((*walk) == 0 || ((*walk) & 0x3ff) != 0) {

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