vboot/vboot_kernel: rewrite kernel version checking code
This CL is part of a series to merge vboot1 and vboot2.0
kernel verification code; see b/181739551.
BUG=b:181739551
TEST=make clean && make runtests
BRANCH=none
Signed-off-by: Joel Kitching <kitching@google.com>
Change-Id: I18790fefe7c4bf2126978c7a9bf1d412dfc8ac78
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/vboot_reference/+/2785809
Tested-by: Joel Kitching <kitching@chromium.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>
Commit-Queue: Joel Kitching <kitching@chromium.org>
diff --git a/firmware/lib/vboot_kernel.c b/firmware/lib/vboot_kernel.c
index 5ba8614..781868b 100644
--- a/firmware/lib/vboot_kernel.c
+++ b/firmware/lib/vboot_kernel.c
@@ -281,23 +281,23 @@
}
/*
- * If the keyblock is valid and we're not in recovery mode, check for
- * rollback of the kernel version.
+ * Kernel preamble version is the lower 16 bits of the composite
+ * kernel version.
*/
- uint32_t combined_version = (key_version << 16) |
- (preamble->kernel_version & 0xFFFF);
- shpart->combined_version = combined_version;
- if (keyblock_valid && boot_mode != VB2_BOOT_MODE_RECOVERY) {
- if (combined_version < sd->kernel_version_secdata) {
- VB2_DEBUG("Kernel version too low.\n");
- shpart->check_result = VBSD_LKP_CHECK_KERNEL_ROLLBACK;
- /*
- * If not in developer mode, kernel version
- * must be valid.
- */
- if (boot_mode != VB2_BOOT_MODE_DEVELOPER)
- return VB2_ERROR_UNKNOWN;
- }
+ if (preamble->kernel_version > VB2_MAX_PREAMBLE_VERSION)
+ return VB2_ERROR_KERNEL_PREAMBLE_VERSION_RANGE;
+
+ /* Combine with the key version. */
+ sd->kernel_version = key_version << 16 | preamble->kernel_version;
+ shpart->combined_version = sd->kernel_version;
+
+ /* If not in recovery mode, check for rollback of the kernel version. */
+ if (need_keyblock_valid &&
+ boot_mode != VB2_BOOT_MODE_RECOVERY &&
+ sd->kernel_version < sd->kernel_version_secdata) {
+ VB2_DEBUG("Kernel version too low.\n");
+ shpart->check_result = VBSD_LKP_CHECK_KERNEL_ROLLBACK;
+ return VB2_ERROR_KERNEL_PREAMBLE_VERSION_ROLLBACK;
}
VB2_DEBUG("Kernel preamble is good.\n");
@@ -577,11 +577,11 @@
if (keyblock_valid) {
sd->flags |= VB2_SD_FLAG_KERNEL_SIGNED;
/* Track lowest version from a valid header. */
- if (lowest_version > shpart->combined_version)
- lowest_version = shpart->combined_version;
+ if (lowest_version > sd->kernel_version)
+ lowest_version = sd->kernel_version;
}
VB2_DEBUG("Keyblock valid: %d\n", keyblock_valid);
- VB2_DEBUG("Combined version: %u\n", shpart->combined_version);
+ VB2_DEBUG("Combined version: %u\n", sd->kernel_version);
/*
* If we're only looking at headers, we're done with this
@@ -630,7 +630,7 @@
* Otherwise, we'll check all the other headers to see if they
* contain a newer key.
*/
- if (shpart->combined_version == sd->kernel_version_secdata) {
+ if (sd->kernel_version == sd->kernel_version_secdata) {
VB2_DEBUG("Same kernel version\n");
break;
}
