From b07fdf9c019f187de4ad8f697fe44a43daad4f86 Mon Sep 17 00:00:00 2001
From: Lucas Silva <lusilva@google.com>
Date: Mon, 2 May 2022 21:46:08 +0000
Subject: [PATCH] Revert "Merge "Restore V2+ signature requirement for system
 apps" into tm-dev am: a347b6c2e6 am: 8aa6d20125"

This reverts commit 613c328e138e4ff7445c53d8407475e4ba056f3d.

Bug: 230910314
Bug: 231165527

Change-Id: If4e49842ddcba42f01c629da54d14bc2d78d541e
Merged-In: a199b313075d10076e80b9275bbfc00c7dbad419
(cherry picked from commit a199b313075d10076e80b9275bbfc00c7dbad419)
---
 .../java/android/content/pm/PackageParser.java |  6 ++++--
 .../server/pm/InstallPackageHelper.java        |  4 ++--
 .../android/server/pm/ScanPackageUtils.java    | 18 ++++++++++--------
 .../pm/pkg/parsing/ParsingPackageUtils.java    |  6 ++++--
 4 files changed, 20 insertions(+), 14 deletions(-)

diff --git a/core/java/android/content/pm/PackageParser.java b/core/java/android/content/pm/PackageParser.java
index 44dc28d2b0faf..4d4a57db84bea 100644
--- a/core/java/android/content/pm/PackageParser.java
+++ b/core/java/android/content/pm/PackageParser.java
@@ -1414,9 +1414,11 @@ public class PackageParser {
         final ParseTypeImpl input = ParseTypeImpl.forDefaultParsing();
         final ParseResult<android.content.pm.SigningDetails> result;
         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.
             result = ApkSignatureVerifier.unsafeGetCertsWithoutVerification(
-                    input, apkPath, minSignatureScheme);
+                    input, apkPath, SigningDetails.SignatureSchemeVersion.JAR);
         } else {
             result = ApkSignatureVerifier.verify(input, apkPath, minSignatureScheme);
         }
diff --git a/services/core/java/com/android/server/pm/InstallPackageHelper.java b/services/core/java/com/android/server/pm/InstallPackageHelper.java
index 57a1fe04b6901..2d8d4f5881925 100644
--- a/services/core/java/com/android/server/pm/InstallPackageHelper.java
+++ b/services/core/java/com/android/server/pm/InstallPackageHelper.java
@@ -4187,8 +4187,8 @@ final class InstallPackageHelper {
                 assertOverlayIsValid(pkg, parseFlags, scanFlags);
             }
 
-            // Ensure the package is signed with at least the minimum signature scheme version
-            // required for its target SDK.
+            // 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.
             ScanPackageUtils.assertMinSignatureSchemeIsValid(pkg, parseFlags);
         }
     }
diff --git a/services/core/java/com/android/server/pm/ScanPackageUtils.java b/services/core/java/com/android/server/pm/ScanPackageUtils.java
index 0dc188b75d5e9..4e8313bf1891d 100644
--- a/services/core/java/com/android/server/pm/ScanPackageUtils.java
+++ b/services/core/java/com/android/server/pm/ScanPackageUtils.java
@@ -690,14 +690,16 @@ final class ScanPackageUtils {
 
     public static void assertMinSignatureSchemeIsValid(AndroidPackage pkg,
             @ParsingPackageUtils.ParseFlags int parseFlags) throws PackageManagerException {
-        int minSignatureSchemeVersion =
-                ApkSignatureVerifier.getMinimumSignatureSchemeVersionForTargetSdk(
-                        pkg.getTargetSdkVersion());
-        if (pkg.getSigningDetails().getSignatureSchemeVersion()
-                < minSignatureSchemeVersion) {
-            throw new PackageManagerException(INSTALL_PARSE_FAILED_NO_CERTIFICATES,
-                    "No signature found in package of version " + minSignatureSchemeVersion
-                            + " or newer for package " + pkg.getPackageName());
+        if ((parseFlags & ParsingPackageUtils.PARSE_IS_SYSTEM_DIR) == 0) {
+            int minSignatureSchemeVersion =
+                    ApkSignatureVerifier.getMinimumSignatureSchemeVersionForTargetSdk(
+                            pkg.getTargetSdkVersion());
+            if (pkg.getSigningDetails().getSignatureSchemeVersion()
+                    < minSignatureSchemeVersion) {
+                throw new PackageManagerException(INSTALL_PARSE_FAILED_NO_CERTIFICATES,
+                        "No signature found in package of version " + minSignatureSchemeVersion
+                                + " or newer for package " + pkg.getPackageName());
+            }
         }
     }
 
diff --git a/services/core/java/com/android/server/pm/pkg/parsing/ParsingPackageUtils.java b/services/core/java/com/android/server/pm/pkg/parsing/ParsingPackageUtils.java
index e1ff9ead6740c..9897c42e4cec6 100644
--- a/services/core/java/com/android/server/pm/pkg/parsing/ParsingPackageUtils.java
+++ b/services/core/java/com/android/server/pm/pkg/parsing/ParsingPackageUtils.java
@@ -3105,9 +3105,11 @@ public class ParsingPackageUtils {
         }
         final ParseResult<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(input, baseCodePath,
-                    minSignatureScheme);
+                    SigningDetails.SignatureSchemeVersion.JAR);
         } else {
             verified = ApkSignatureVerifier.verify(input, baseCodePath, minSignatureScheme);
         }