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#unl... Fixes: 125d9f3306ea ("bootstd: Add a bootmeth for Android") Signed-off-by: Mattijs Korpershoek mkorpershoek@baylibre.com --- boot/bootmeth_android.c | 37 ++++++++++++++++++++++++------------- 1 file changed, 24 insertions(+), 13 deletions(-)
diff --git a/boot/bootmeth_android.c b/boot/bootmeth_android.c index 2cd167f80280801618a317a65e93a10e70a0d9ee..dc9aad1633bb7a6d577013bfa0f939343f2e066b 100644 --- a/boot/bootmeth_android.c +++ b/boot/bootmeth_android.c @@ -407,17 +407,26 @@ static int run_avb_verification(struct bootflow *bflow) AVB_HASHTREE_ERROR_MODE_RESTART_AND_INVALIDATE, &out_data);
- if (result != AVB_SLOT_VERIFY_RESULT_OK) { - 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); - } - - if (unlocked) - boot_state = AVB_ORANGE; - else + if (!unlocked) { + /* When device is locked, we only accept AVB_SLOT_VERIFY_RESULT_OK */ + if (result != AVB_SLOT_VERIFY_RESULT_OK) { + 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); + } boot_state = AVB_GREEN; + } else { + /* When device is unlocked, we also accept verification errors */ + if (result != AVB_SLOT_VERIFY_RESULT_OK && + result != AVB_SLOT_VERIFY_RESULT_ERROR_VERIFICATION) { + 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); + } + boot_state = AVB_ORANGE; + }
extra_args = avb_set_state(avb_ops, boot_state); if (extra_args) { @@ -427,9 +436,11 @@ 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;