From 3339f41d2692e2e03ece172bedbaea767270500c Mon Sep 17 00:00:00 2001
From: Christian Lamparter <chunkeey@googlemail.com>
Date: Thu, 7 Apr 2016 18:26:51 +0200
Subject: [PATCH] brcm2708: implement sysupgrade image check
Implement a crude but functioning sysupgrade image check for the
Raspberry Pi. The code only checks if the master boot record boot
signature (0x55aa) is present in the first 512-bytes at the correct
location. This can prevent the odd bricking of a system when flashing
the wrong file.
Signed-off-by: Christian Lamparter <chunkeey@googlemail.com>
---
.../brcm2708/base-files/lib/upgrade/platform.sh | 16 +++++++++++++++-
1 file changed, 15 insertions(+), 1 deletion(-)
diff --git a/target/linux/brcm2708/base-files/lib/upgrade/platform.sh b/target/linux/brcm2708/base-files/lib/upgrade/platform.sh
index 1d4b694574c..2f2aeb098e2 100644
--- a/target/linux/brcm2708/base-files/lib/upgrade/platform.sh
+++ b/target/linux/brcm2708/base-files/lib/upgrade/platform.sh
@@ -1,5 +1,19 @@
+get_magic_at() {
+ local file="$1"
+ local pos="$2"
+ get_image "$file" | dd bs=1 count=2 skip="$pos" 2>/dev/null | hexdump -v -n 2 -e '1/1 "%02x"'
+}
+
platform_check_image() {
- # i know no way to verify the image
+ local file="$1"
+ local magic
+
+ magic=$(get_magic_at "$file" 510)
+ [ "$magic" != "55aa" ] && {
+ echo "Failed to verify MBR boot signature."
+ return 1
+ }
+
return 0;
}
--
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