Verify wipe package when wiping A/B device in recovery.
To increase the security of wiping A/B devices, let uncrypt write
wipe package in misc partition. Then recovery verifies the wipe
package before wiping the device.
Bug: 29159185
Change-Id: I186691bab1928d3dc036bc5542abd64a81bc2168
diff --git a/uncrypt/bootloader_message_writer.cpp b/uncrypt/bootloader_message_writer.cpp
index 3bb106a..42df31e 100644
--- a/uncrypt/bootloader_message_writer.cpp
+++ b/uncrypt/bootloader_message_writer.cpp
@@ -58,7 +58,7 @@
return record->blk_device;
}
-static bool write_bootloader_message(const bootloader_message& boot, std::string* err) {
+static bool write_misc_partition(const void* p, size_t size, size_t misc_offset, std::string* err) {
std::string misc_blk_device = get_misc_blk_device(err);
if (misc_blk_device.empty()) {
return false;
@@ -69,11 +69,18 @@
strerror(errno));
return false;
}
- if (!android::base::WriteFully(fd.get(), &boot, sizeof(boot))) {
+ if (lseek(fd.get(), static_cast<off_t>(misc_offset), SEEK_SET) !=
+ static_cast<off_t>(misc_offset)) {
+ *err = android::base::StringPrintf("failed to lseek %s: %s", misc_blk_device.c_str(),
+ strerror(errno));
+ return false;
+ }
+ if (!android::base::WriteFully(fd.get(), p, size)) {
*err = android::base::StringPrintf("failed to write %s: %s", misc_blk_device.c_str(),
strerror(errno));
return false;
}
+
// TODO: O_SYNC and fsync duplicates each other?
if (fsync(fd.get()) == -1) {
*err = android::base::StringPrintf("failed to fsync %s: %s", misc_blk_device.c_str(),
@@ -83,6 +90,10 @@
return true;
}
+static bool write_bootloader_message(const bootloader_message& boot, std::string* err) {
+ return write_misc_partition(&boot, sizeof(boot), BOOTLOADER_MESSAGE_OFFSET_IN_MISC, err);
+}
+
bool clear_bootloader_message(std::string* err) {
bootloader_message boot = {};
return write_bootloader_message(boot, err);
@@ -101,6 +112,11 @@
return write_bootloader_message(boot, err);
}
+bool write_wipe_package(const std::string& package_data, std::string* err) {
+ return write_misc_partition(package_data.data(), package_data.size(),
+ WIPE_PACKAGE_OFFSET_IN_MISC, err);
+}
+
extern "C" bool write_bootloader_message(const char* options) {
std::string err;
return write_bootloader_message({options}, &err);
diff --git a/uncrypt/include/bootloader_message_writer.h b/uncrypt/include/bootloader_message_writer.h
index e0ca3f4..1344bc8 100644
--- a/uncrypt/include/bootloader_message_writer.h
+++ b/uncrypt/include/bootloader_message_writer.h
@@ -24,6 +24,7 @@
bool clear_bootloader_message(std::string* err);
bool write_bootloader_message(const std::vector<std::string>& options, std::string* err);
+bool write_wipe_package(const std::string& package_data, std::string* err);
#else
#include <stdbool.h>
diff --git a/uncrypt/uncrypt.cpp b/uncrypt/uncrypt.cpp
index d7105a0..f62d132 100644
--- a/uncrypt/uncrypt.cpp
+++ b/uncrypt/uncrypt.cpp
@@ -503,14 +503,31 @@
return false;
}
ALOGI(" received command: [%s] (%zu)", content.c_str(), content.size());
+ std::vector<std::string> options = android::base::Split(content, "\n");
+ std::string wipe_package;
+ for (auto& option : options) {
+ if (android::base::StartsWith(option, "--wipe_package=")) {
+ std::string path = option.substr(strlen("--wipe_package="));
+ if (!android::base::ReadFileToString(path, &wipe_package)) {
+ ALOGE("failed to read %s: %s", path.c_str(), strerror(errno));
+ return false;
+ }
+ option = android::base::StringPrintf("--wipe_package_size=%zu", wipe_package.size());
+ }
+ }
// c8. setup the bcb command
std::string err;
- if (!write_bootloader_message({content}, &err)) {
+ if (!write_bootloader_message(options, &err)) {
ALOGE("failed to set bootloader message: %s", err.c_str());
write_status_to_socket(-1, socket);
return false;
}
+ if (!wipe_package.empty() && !write_wipe_package(wipe_package, &err)) {
+ ALOGE("failed to set wipe package: %s", err.c_str());
+ write_status_to_socket(-1, socket);
+ return false;
+ }
// c10. send "100" status
write_status_to_socket(100, socket);
return true;