Improve coreboot image detection heuristic
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.
Corresponding to flashrom svn r292 and coreboot v2 svn r3408.
Signed-off-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006@gmx.net>
Acked-by: Stefan Reinauer <stepan@coresystems.de>
diff --git a/layout.c b/layout.c
index a738fb2..f41e0ea 100644
--- a/layout.c
+++ b/layout.c
@@ -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;