chromeos-base/chromeos-installer/files/installer-support-new-dm-format.patch

From f1f6ccb855ba3ae9b6b970304a28b9380d62367b Mon Sep 17 00:00:00 2001
From: Meena Shanmugam <meenashanmugam@google.com>
Date: Mon, 10 Oct 2022 00:10:18 +0000
Subject: [PATCH] LAKITU:chromeos-installer: Update postinstall programs to use
 new dm format.

COS uses upstream dm format for the upcoming releases. Automatic updates
update the bootloader configurations. Inorder to auto-update work with
the upstream format, these auto-update postinstall programs need to be
modified to support both new and old format. Once these changes are
approved and merged in chromeOS upstream, this patch can be removed.

Change-Id: Icb9af46e0b2bed4aa7c44f658d1b49252fc993bc
---
 installer/chromeos_legacy.cc   | 31 ++++++++++++++++++++++++------
 installer/chromeos_setimage.cc | 35 +++++++++++++++++++++++++++++-----
 2 files changed, 55 insertions(+), 11 deletions(-)

diff --git a/installer/chromeos_legacy.cc b/installer/chromeos_legacy.cc
index 2ebc7e9d51..9bc2cd0813 100644
--- a/installer/chromeos_legacy.cc
+++ b/installer/chromeos_legacy.cc
@@ -43,7 +43,10 @@ std::string EfiGrubCfg::GetKernelCommand(BootSlot slot,
     if (line.find(kernel_pattern) == string::npos)
       continue;
 
-    if (ExtractKernelArg(line, "dm").empty() == want_empty_dm)
+    bool got_empty_dm =
+        ExtractKernelArg(line, "dm").empty() &&
+        ExtractKernelArg(line, "dm-mod.create").empty();
+    if (got_empty_dm == want_empty_dm)
       return line;
   }
   return "";
@@ -59,7 +62,10 @@ bool EfiGrubCfg::ReplaceKernelCommand(BootSlot slot,
     if (line.find(kernel_pattern) == string::npos)
       continue;
 
-    if (ExtractKernelArg(line, "dm").empty() == want_empty_dm) {
+    bool got_empty_dm = 
+        ExtractKernelArg(line, "dm").empty() &&
+        ExtractKernelArg(line, "dm-mod.create").empty();
+    if (got_empty_dm == want_empty_dm) {
       DLOG(INFO) << "Replacing: " << line;
       line = cmd;
       // Continue to replace all matching lines.
@@ -100,15 +106,25 @@ bool EfiGrubCfg::UpdateBootParameters(BootSlot slot,
       continue;
 
     DLOG(INFO) << "Updating command: " << line;
-    if (ExtractKernelArg(line, "dm").empty()) {
+    if (ExtractKernelArg(line, "dm").empty() &&
+        ExtractKernelArg(line, "dm-mod.create").empty()) {
       // If it's an unverified boot line, just set the root partition to boot.
       if (!SetKernelArg("root", "PARTUUID=" + root_uuid, &line)) {
         LOG(ERROR) << "Unable to update unverified root flag in " << line;
         return false;
       }
-    } else if (!SetKernelArg("dm", verity_args, &line)) {
-      LOG(INFO) << "Unable to update verified dm flag.";
-      return false;
+    } else {
+      if (!SetKernelArg("dm", verity_args, &line)) {
+        if (!SetKernelArg("dm-mod.create", verity_args, &line)) {
+          LOG(INFO) << "Unable to update verified dm flag.";
+          return false;
+        }
+      }
+      // Update grub.cfg with the new dm format
+      std::size_t found = line.find("dm=");
+      if (found != std::string::npos) {
+        line.replace(found, 3, "dm-mod.create=");
+      }
     }
   }
   return true;
@@ -149,6 +165,9 @@ bool UpdateLegacyKernel(const InstallConfig& install_config) {
 string ExpandVerityArguments(const string& kernel_config,
                              const string& root_uuid) {
   string kernel_config_dm = ExtractKernelArg(kernel_config, "dm");
+  if ( kernel_config_dm.empty()) {
+    kernel_config_dm = ExtractKernelArg(kernel_config, "dm-mod.create");
+  }
 
   // The verity config from the kernel contains short hand symbols for
   // partition names that we have to expand to specific UUIDs.
diff --git a/installer/chromeos_setimage.cc b/installer/chromeos_setimage.cc
index ff13439430..3af4d6589c 100644
--- a/installer/chromeos_setimage.cc
+++ b/installer/chromeos_setimage.cc
@@ -78,7 +78,12 @@ bool SetImage(const InstallConfig& install_config) {
 
   base::FilePath kernel_config_root =
       base::FilePath(ExtractKernelArg(kernel_config, "root"));
+  int version = 0;
   string dm_config = ExtractKernelArg(kernel_config, "dm");
+  if (dm_config.empty()) {
+    dm_config = ExtractKernelArg(kernel_config, "dm-mod.create");
+    version =1;
+  }
   std::vector<string> dm_parts = base::SplitString(
       dm_config, ",", base::KEEP_WHITESPACE, base::SPLIT_WANT_ALL);
 
@@ -96,11 +101,24 @@ bool SetImage(const InstallConfig& install_config) {
     return false;
   }
 
+  string rootfs_sectors;
+  string verity_algorithm;
+  string expected_hash;
+  string salt;
   // Extract specific verity arguments
-  string rootfs_sectors = ExtractKernelArg(verity_args, "hashstart");
-  string verity_algorithm = ExtractKernelArg(verity_args, "alg");
-  string expected_hash = ExtractKernelArg(verity_args, "root_hexdigest");
-  string salt = ExtractKernelArg(verity_args, "salt");
+  if (version == 1) {
+    std::vector<string> verity_parts = base::SplitString(
+        verity_args, " ", base::KEEP_WHITESPACE, base::SPLIT_WANT_ALL);
+    rootfs_sectors = verity_parts[9];
+    verity_algorithm = verity_parts[10];
+    expected_hash = verity_parts[11];
+    salt = verity_parts[12];
+  } else {
+    rootfs_sectors = ExtractKernelArg(verity_args, "hashstart");
+    verity_algorithm = ExtractKernelArg(verity_args, "alg");
+    expected_hash = ExtractKernelArg(verity_args, "root_hexdigest");
+    salt = ExtractKernelArg(verity_args, "salt");
+  }
 
   bool enable_rootfs_verification = IsReadonly(kernel_config_root);
 
@@ -110,9 +128,16 @@ bool SetImage(const InstallConfig& install_config) {
   LOG(INFO) << "Setting up verity.";
   LoggingTimerStart();
   verity::DmBht bht;
+  uint64_t sectors;
+  if (version == 1) {
+    sectors = (atoi(rootfs_sectors.c_str()) << 3) / 8;
+  } else {
+    sectors = (atoi(rootfs_sectors.c_str())) / 8;
+  }
+
   int result = chromeos_verity(&bht, verity_algorithm,
                                install_config.root.device(), getpagesize(),
-                               (uint64_t)(atoi(rootfs_sectors.c_str()) / 8),
+                               sectors,
                                salt, expected_hash, enable_rootfs_verification);
   LoggingTimerFinish();
 
-- 
2.41.0.390.g38632f3daf-goog