From 01c3d11b83bfca88d3fd382b1f51b41a8ffb1506 Mon Sep 17 00:00:00 2001
From: Michael Groover <mpgroover@google.com>
Date: Mon, 7 Mar 2022 22:15:46 +0000
Subject: [PATCH] Revert "[DO NOT MERGE]Revert "Relax minimum signature scheme
 ver..."

Revert submission 16943318-presubmit-am-bc566b73c1674298b82a1153c03313a1

Reason for revert: This change breaks Better Bug.
Reverted Changes:
I32a2db8c7:[automerge] [DO NOT MERGE]Revert "Relax minimum si...
Ic53d2a361:[DO NOT MERGE]Revert "Relax minimum signature sche...

Bug: 223079119

Change-Id: I987bda9df92543f082700936c20aad06f992bdb0
---
 .../android/content/pm/PackageParser.java     |  6 ++++--
 .../pm/parsing/ParsingPackageUtils.java       |  6 ++++--
 .../server/pm/PackageManagerService.java      | 20 ++++++++++---------
 3 files changed, 19 insertions(+), 13 deletions(-)

diff --git a/core/java/android/content/pm/PackageParser.java b/core/java/android/content/pm/PackageParser.java
index f54d9a76d02dc..4ff26242dab2b 100644
--- a/core/java/android/content/pm/PackageParser.java
+++ b/core/java/android/content/pm/PackageParser.java
@@ -1401,9 +1401,11 @@ public class PackageParser {
         }
         SigningDetails verified;
         if (skipVerify) {
-            // systemDir APKs are already trusted, save time by not verifying
+            // systemDir APKs are already trusted, save time by not verifying; since the signature
+            // is not verified and some system apps can have their V2+ signatures stripped allow
+            // pulling the certs from the jar signature.
             verified = ApkSignatureVerifier.unsafeGetCertsWithoutVerification(
-                        apkPath, minSignatureScheme);
+                        apkPath, SigningDetails.SignatureSchemeVersion.JAR);
         } else {
             verified = ApkSignatureVerifier.verify(apkPath, minSignatureScheme);
         }
diff --git a/core/java/android/content/pm/parsing/ParsingPackageUtils.java b/core/java/android/content/pm/parsing/ParsingPackageUtils.java
index e1d34dc3f622b..dce242c9d87c5 100644
--- a/core/java/android/content/pm/parsing/ParsingPackageUtils.java
+++ b/core/java/android/content/pm/parsing/ParsingPackageUtils.java
@@ -3038,9 +3038,11 @@ public class ParsingPackageUtils {
         SigningDetails verified;
         try {
             if (skipVerify) {
-                // systemDir APKs are already trusted, save time by not verifying
+                // systemDir APKs are already trusted, save time by not verifying; since the
+                // signature is not verified and some system apps can have their V2+ signatures
+                // stripped allow pulling the certs from the jar signature.
                 verified = ApkSignatureVerifier.unsafeGetCertsWithoutVerification(
-                        baseCodePath, minSignatureScheme);
+                        baseCodePath, SigningDetails.SignatureSchemeVersion.JAR);
             } else {
                 verified = ApkSignatureVerifier.verify(baseCodePath, minSignatureScheme);
             }
diff --git a/services/core/java/com/android/server/pm/PackageManagerService.java b/services/core/java/com/android/server/pm/PackageManagerService.java
index b5957052d5a85..c0486443b97ec 100644
--- a/services/core/java/com/android/server/pm/PackageManagerService.java
+++ b/services/core/java/com/android/server/pm/PackageManagerService.java
@@ -15193,15 +15193,17 @@ public class PackageManagerService extends IPackageManager.Stub
                 }
             }
 
-            // Ensure the package is signed with at least the minimum signature scheme version
-            // required for its target SDK.
-            int minSignatureSchemeVersion =
-                    ApkSignatureVerifier.getMinimumSignatureSchemeVersionForTargetSdk(
-                            pkg.getTargetSdkVersion());
-            if (pkg.getSigningDetails().signatureSchemeVersion < minSignatureSchemeVersion) {
-                throw new PackageManagerException(INSTALL_PARSE_FAILED_NO_CERTIFICATES,
-                        "No signature found in package of version " + minSignatureSchemeVersion
-                                + " or newer for package " + pkg.getPackageName());
+            // If the package is not on a system partition ensure it is signed with at least the
+            // minimum signature scheme version required for its target SDK.
+            if ((parseFlags & ParsingPackageUtils.PARSE_IS_SYSTEM_DIR) == 0) {
+                int minSignatureSchemeVersion =
+                        ApkSignatureVerifier.getMinimumSignatureSchemeVersionForTargetSdk(
+                                pkg.getTargetSdkVersion());
+                if (pkg.getSigningDetails().signatureSchemeVersion < minSignatureSchemeVersion) {
+                    throw new PackageManagerException(INSTALL_PARSE_FAILED_NO_CERTIFICATES,
+                            "No signature found in package of version " + minSignatureSchemeVersion
+                                    + " or newer for package " + pkg.getPackageName());
+                }
             }
         }
     }