From fa9d7782e837848a1aeb0e95295fa48ac23f7a26 Mon Sep 17 00:00:00 2001 From: Bill Richardson Date: Wed, 9 Nov 2011 09:11:34 -0800 Subject: Dev-mode only boots official kernels by default Although we're now using a single unified BIOS, it is pretty nice to be able to get a shell in developer mode while still using verified boot for the kernel and filesystem. Alex & ZGB implemented this by requiring the dev-mode user to install a special dev-mode BIOS. We don't do that, but we DO require setting a special flag with "crossystem" to accomplish the same thing. In order to allow booting a self-signed kernel, you must boot in developer mode, open a shell, and run this: crossystem dev_boot_custom=1 Special note to internal developers: If you're in the habit (as I am) of booting directly from a USB stick in dev-mode, you'll have to run this: crossystem dev_boot_custom=1 dev_boot_usb=1 Just using dev_boot_usb=1 is no longer enough, because the USB kernel is signed using the recovery key and by pressing Ctrl-U, we validate it with the kernel data key. That worked before this change because any self-signed kernel was fine, and that's how the USB key was treated. Now it actually requires a verified signature until you enable dev_boot_custom=1 also. BUG=chrome-os-partner:5954 TEST=manual Boot once in normal mode, which clears the special flags. Then switch to developer mode. You should be able to boot and get a root shell. Run crossystem dev_boot_usb=1 Obtain a USB recovery image that's keyed differently. For example, if you're testing with dev-keys, use a PVT-signed image or vice-versa. Reboot into dev-mode with the USB recovery stick inserted. At the dev-mode screen, press Ctrl-U. You should hear a single beep, but it should not boot. Press Ctrl-D to boot from the hard drive, log in to a shell and run crossystem dev_boot_custom=1 Repeat the previous test. This time when you press Ctrl-U, it should boot the recovery image. Turn the system off before it does anything. That's it. Change-Id: I1811ee9a188974b3f94c83c52b00b60028b86c69 Reviewed-on: https://gerrit.chromium.org/gerrit/11442 Tested-by: Bill Richardson Reviewed-by: Randall Spangler --- firmware/include/vboot_struct.h | 1 + 1 file changed, 1 insertion(+) (limited to 'firmware/include/vboot_struct.h') diff --git a/firmware/include/vboot_struct.h b/firmware/include/vboot_struct.h index 795523ed..3374d4cc 100644 --- a/firmware/include/vboot_struct.h +++ b/firmware/include/vboot_struct.h @@ -234,6 +234,7 @@ typedef struct VbKernelPreambleHeader { #define VBSD_LKP_CHECK_PREAMBLE_VALID 11 #define VBSD_LKP_CHECK_BODY_ADDRESS 12 #define VBSD_LKP_CHECK_BODY_OFFSET 13 +#define VBSD_LKP_CHECK_SELF_SIGNED 14 #define VBSD_LKP_CHECK_BODY_EXCEEDS_MEM 15 #define VBSD_LKP_CHECK_BODY_EXCEEDS_PART 16 #define VBSD_LKP_CHECK_READ_DATA 17 -- cgit v1.2.1