[PATCH 2/2] bootstd: android: Allow boot with AVB failures when unlocked

[Mattijs Korpershoek]

Hi,

Please ignore this patch, I've send this a bit too fast and did not test
all the cases.

Sorry for the noise.

Mattijs

On mer., janv. 08, 2025 at 14:43, Mattijs Korpershoek <mkorpershoek at baylibre.com> wrote:

> When the bootloader is UNLOCKED, it should be possible to boot Android
> even if AVB reports verification errors [1].
>
> This allows developers to flash modified partitions on
> userdebug/engineering builds.
>
> Developers can do so on unlocked devices with:
> $ fastboot flash --disable-verity --disable-verification vbmeta vbmeta.img
>
> In such case, bootmeth_android refuses to boot.
>
> Allow the boot to continue when the device is UNLOCKED and AVB reports
> verification errors.
>
> [1] https://source.android.com/docs/security/features/verifiedboot/boot-flow#unlocked-devices
> Fixes: 125d9f3306ea ("bootstd: Add a bootmeth for Android")
> Signed-off-by: Mattijs Korpershoek <mkorpershoek at baylibre.com>
> ---
>  boot/bootmeth_android.c | 15 +++++++++++----
>  1 file changed, 11 insertions(+), 4 deletions(-)
>
> diff --git a/boot/bootmeth_android.c b/boot/bootmeth_android.c
> index 2cd167f80280801618a317a65e93a10e70a0d9ee..564d21784feb0667bf9bed2a59be0a232601a7dd 100644
> --- a/boot/bootmeth_android.c
> +++ b/boot/bootmeth_android.c
> @@ -407,11 +407,16 @@ static int run_avb_verification(struct bootflow *bflow)
>  				 AVB_HASHTREE_ERROR_MODE_RESTART_AND_INVALIDATE,
>  				 &out_data);
>  
> -	if (result != AVB_SLOT_VERIFY_RESULT_OK) {
> +	if (result != AVB_SLOT_VERIFY_RESULT_OK && !unlocked) {
>  		printf("Verification failed, reason: %s\n",
>  		       str_avb_slot_error(result));
>  		avb_slot_verify_data_free(out_data);
>  		return log_msg_ret("avb verify", -EIO);
> +	} else if (result != AVB_SLOT_VERIFY_RESULT_ERROR_VERIFICATION && unlocked) {
> +		printf("Unlocked verification failed, reason: %s\n",
> +		       str_avb_slot_error(result));
> +		avb_slot_verify_data_free(out_data);
> +		return log_msg_ret("avb verify unlocked", -EIO);
>  	}
>  
>  	if (unlocked)
> @@ -427,9 +432,11 @@ static int run_avb_verification(struct bootflow *bflow)
>  			goto free_out_data;
>  	}
>  
> -	ret = avb_append_commandline(bflow, out_data->cmdline);
> -	if (ret < 0)
> -		goto free_out_data;
> +	if (result == AVB_SLOT_VERIFY_RESULT_OK) {
> +		ret = avb_append_commandline(bflow, out_data->cmdline);
> +		if (ret < 0)
> +			goto free_out_data;
> +	}
>  
>  	return 0;
>  
>
> -- 
> 2.47.1