update_verifier should read dm wrapped partition
update_verifier used to read from system_block_device, which bypasses
dm-verity check completely. Switch update_verifier to read the corresponding
'/dev/block/dm-X' instead. U_v gets the verity block device number by
comparing the contents in '/sys/block/dm-X/dm/name'.
Bug: 34391662
Test: update_verifier detects the corrupped blocks and dm-verity trigger the reboot on Sailfish.
Change-Id: Ie5c50c23410bd29fcc6e733ba29cf892e9a07460
diff --git a/update_verifier/update_verifier.cpp b/update_verifier/update_verifier.cpp
index 1c9be2d..a4799cc 100644
--- a/update_verifier/update_verifier.cpp
+++ b/update_verifier/update_verifier.cpp
@@ -30,6 +30,7 @@
* verifier reaches the end after the verification.
*/
+#include <dirent.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
@@ -52,14 +53,71 @@
using android::hardware::boot::V1_0::CommandResult;
constexpr auto CARE_MAP_FILE = "/data/ota_package/care_map.txt";
+constexpr auto DM_PATH_PREFIX = "/sys/block/";
+constexpr auto DM_PATH_SUFFIX = "/dm/name";
+constexpr auto DEV_PATH = "/dev/block/";
constexpr int BLOCKSIZE = 4096;
-static bool read_blocks(const std::string& blk_device_prefix, const std::string& range_str) {
- std::string slot_suffix = android::base::GetProperty("ro.boot.slot_suffix", "");
- std::string blk_device = blk_device_prefix + slot_suffix;
- android::base::unique_fd fd(TEMP_FAILURE_RETRY(open(blk_device.c_str(), O_RDONLY)));
+// Find directories in format of "/sys/block/dm-X".
+static int dm_name_filter(const dirent* de) {
+ if (android::base::StartsWith(de->d_name, "dm-")) {
+ return 1;
+ }
+ return 0;
+}
+
+static bool read_blocks(const std::string& blk_device, const std::string& range_str) {
+ // Parse the partition in the end of the block_device string.
+ // Here is one example: "/dev/block/bootdevice/by-name/system"
+ std::string partition;
+ if (android::base::EndsWith(blk_device, "system")) {
+ partition = "system";
+ } else if (android::base::EndsWith(blk_device, "vendor")) {
+ partition = "vendor";
+ } else {
+ LOG(ERROR) << "Failed to parse partition string in " << blk_device;
+ return false;
+ }
+
+ // Iterate the content of "/sys/block/dm-X/dm/name". If it matches "system"
+ // (or "vendor"), then dm-X is a dm-wrapped system/vendor partition.
+ // Afterwards, update_verifier will read every block on the care_map_file of
+ // "/dev/block/dm-X" to ensure the partition's integrity.
+ dirent** namelist;
+ int n = scandir(DM_PATH_PREFIX, &namelist, dm_name_filter, alphasort);
+ if (n == -1) {
+ PLOG(ERROR) << "Failed to scan dir " << DM_PATH_PREFIX;
+ return false;
+ }
+ if (n == 0) {
+ LOG(ERROR) << "dm block device not found for " << partition;
+ return false;
+ }
+
+ std::string dm_block_device;
+ while (n--) {
+ std::string path = DM_PATH_PREFIX + std::string(namelist[n]->d_name) + DM_PATH_SUFFIX;
+ std::string content;
+ if (!android::base::ReadFileToString(path, &content)) {
+ PLOG(WARNING) << "Failed to read " << path;
+ } else if (android::base::Trim(content) == partition) {
+ dm_block_device = DEV_PATH + std::string(namelist[n]->d_name);
+ while (n--) {
+ free(namelist[n]);
+ }
+ break;
+ }
+ free(namelist[n]);
+ }
+ free(namelist);
+
+ if (dm_block_device.empty()) {
+ LOG(ERROR) << "Failed to find dm block device for " << partition;
+ return false;
+ }
+ android::base::unique_fd fd(TEMP_FAILURE_RETRY(open(dm_block_device.c_str(), O_RDONLY)));
if (fd.get() == -1) {
- PLOG(ERROR) << "Error reading partition " << blk_device;
+ PLOG(ERROR) << "Error reading " << dm_block_device << " for partition " << partition;
return false;
}
@@ -100,7 +158,7 @@
blk_count += (range_end - range_start);
}
- LOG(INFO) << "Finished reading " << blk_count << " blocks on " << blk_device;
+ LOG(INFO) << "Finished reading " << blk_count << " blocks on " << dm_block_device;
return true;
}