From 682d2a5db2a61a6f97c09d7c143e023fe2bd4e14 Mon Sep 17 00:00:00 2001 From: David Anderson Date: Wed, 20 Nov 2019 15:47:07 -0800 Subject: bootloader_message: Add a magic header to the Virtual A/B message block. This adds a sanity check in addition to the version number in case misc contains random bits. Bug: 139156011 Test: manual test Change-Id: Ie4f3731d2b1795340881c88e0c4eec9cd4432653 --- boot_control/libboot_control.cpp | 4 +++- bootloader_message/include/bootloader_message/bootloader_message.h | 6 ++++-- 2 files changed, 7 insertions(+), 3 deletions(-) diff --git a/boot_control/libboot_control.cpp b/boot_control/libboot_control.cpp index 702183979..ab9ce971b 100644 --- a/boot_control/libboot_control.cpp +++ b/boot_control/libboot_control.cpp @@ -365,13 +365,15 @@ bool InitMiscVirtualAbMessageIfNeeded() { return false; } - if (message.version == MISC_VIRTUAL_AB_MESSAGE_VERSION) { + if (message.version == MISC_VIRTUAL_AB_MESSAGE_VERSION && + message.magic == MISC_VIRTUAL_AB_MAGIC_HEADER) { // Already initialized. return true; } message = {}; message.version = MISC_VIRTUAL_AB_MESSAGE_VERSION; + message.magic = MISC_VIRTUAL_AB_MAGIC_HEADER; if (!WriteMiscVirtualAbMessage(message, &err)) { LOG(ERROR) << "Could not write merge status: " << err; return false; diff --git a/bootloader_message/include/bootloader_message/bootloader_message.h b/bootloader_message/include/bootloader_message/bootloader_message.h index a27e80bcc..9a482d423 100644 --- a/bootloader_message/include/bootloader_message/bootloader_message.h +++ b/bootloader_message/include/bootloader_message/bootloader_message.h @@ -189,12 +189,14 @@ static_assert(sizeof(struct bootloader_control) == // must be added to the end. struct misc_virtual_ab_message { uint8_t version; + uint32_t magic; uint8_t merge_status; // IBootControl 1.1, MergeStatus enum. uint8_t source_slot; // Slot number when merge_status was written. - uint8_t reserved[61]; + uint8_t reserved[57]; } __attribute__((packed)); -#define MISC_VIRTUAL_AB_MESSAGE_VERSION 1 +#define MISC_VIRTUAL_AB_MESSAGE_VERSION 2 +#define MISC_VIRTUAL_AB_MAGIC_HEADER 0x56740AB0 #if (__STDC_VERSION__ >= 201112L) || defined(__cplusplus) static_assert(sizeof(struct misc_virtual_ab_message) == 64, -- cgit v1.2.3