futility: Wipe GBB data before writing new values.
The previous version of gbb_utility always zeros data before writing new values
and we should keep this behavior, to simplify firmware hash calculation and
potential security concern.
BRANCH=none
BUG=chromium:413066
TEST=emerge gbb_utility; factory/bin/gooftool get_firmware_hash bios.bin
Originial-Change-Id: Ic97a118cefc9698d52d9370b627670ff103d5e23
Change-Id: If199040909c4719c89dbc52fd7488d69abd981e5
Reviewed-on: https://chromium-review.googlesource.com/217478
Reviewed-by: Hung-Te Lin <hungte@chromium.org>
Commit-Queue: Hung-Te Lin <hungte@chromium.org>
Tested-by: Hung-Te Lin <hungte@chromium.org>
diff --git a/futility/cmd_gbb_utility.c b/futility/cmd_gbb_utility.c
index 9810058..85b4782 100644
--- a/futility/cmd_gbb_utility.c
+++ b/futility/cmd_gbb_utility.c
@@ -342,6 +342,9 @@
goto done_close;
}
+ /* Wipe existing data. */
+ memset(start, 0, size);
+
/* It's okay if we read less than size. That's just the max. */
count = fread(start, 1, size, fp);
if (ferror(fp)) {
@@ -568,6 +571,9 @@
gbb->hwid_size);
errorcnt++;
} else {
+ /* Wipe data before writing new value. */
+ memset(gbb_base + gbb->hwid_offset, 0,
+ gbb->hwid_size);
strcpy((char *)(gbb_base + gbb->hwid_offset),
opt_hwid);
}
