[coreboot] [PATCH] flashrom: Improve coreboot image detection heuristic
Carl-Daniel Hailfinger
c-d.hailfinger.devel.2006 at gmx.net
Fri Jul 4 21:00:06 CEST 2008
On 04.07.2008 19:17, Stefan Reinauer wrote:
> Carl-Daniel Hailfinger wrote:
>
>
>> Sorry. I had a correct version, but it seems I pressed undo before saving.
>>
>> Fix coreboot image detection heuristic.
>>
>> Signed-off-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006 at gmx.net>
>>
>>
>
> I wonder whether it makes sense to explicitly say !=0 for the
> non-isprint parts to express that those are not booleans but checks
> whether a char is 0
>
I came to the conclusion that matching a possibly empty string in the
ROM does not make sense.
Cleaned up patch follows. It compiles for me, is a LOT more readable and
even removes hard-to-follow code from layout.c.
Signed-off-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006 at gmx.net>
Index: layout.c
===================================================================
--- layout.c (Revision 3412)
+++ layout.c (Arbeitskopie)
@@ -45,7 +45,12 @@
int show_id(uint8_t *bios, int size, int force)
{
unsigned int *walk;
+ unsigned int mb_part_offset, mb_vendor_offset;
+ char *mb_part, *mb_vendor;
+ mainboard_vendor = def_name;
+ mainboard_part = def_name;
+
walk = (unsigned int *)(bios + size - 0x10);
walk--;
@@ -63,25 +68,27 @@
* 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))))) {
+ mb_part_offset = *(walk - 1);
+ mb_vendor_offset = *(walk - 2);
+ if ((*walk) == 0 || ((*walk) & 0x3ff) != 0 || (*walk) > size ||
+ mb_part_offset > size || mb_vendor_offset > size) {
printf("Flash image seems to be a legacy BIOS. Disabling checks.\n");
- mainboard_vendor = def_name;
- mainboard_part = def_name;
return 0;
}
+
+ mb_part = (char *)(bios + size - mb_part_offset);
+ mb_vendor = (char *)(bios + size - mb_vendor_offset);
+ if (!isprint(*mb_part) || !isprint(*mb_vendor)) {
+ printf("Flash image seems to have garbage in the ID location."
+ " Disabling checks.\n");
+ return 0;
+ }
printf_debug("coreboot last image size "
"(not ROM size) is %d bytes.\n", *walk);
- walk--;
- mainboard_part = strdup((const char *)(bios + size - *walk));
- walk--;
- mainboard_vendor = strdup((const char *)(bios + size - *walk));
+ mainboard_part = strdup(mb_part);
+ mainboard_vendor = strdup(mb_vendor);
printf_debug("Manufacturer: %s\n", mainboard_vendor);
printf_debug("Mainboard ID: %s\n", mainboard_part);
--
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