[encryption] fix MGF1 digest for Keystore-backed keys

.github/workflows/instrumented-tests.yml

@@ -0,0 +1,79 @@
+name: Instrumented Tests
+
+on:
+  pull_request: { types: [opened, synchronize, ready_for_review] }
+  push: { branches: [master] }
+
+jobs:
+  # Device-paired E2E lives behind Android Keystore, whose RSA-OAEP behaviour is
+  # API-level dependent, so a JVM unit test cannot cover it - build-apk.yml only runs
+  # `./gradlew test`. These levels are the ones that matter: 25 and 30 exercise the
+  # Keystore1 provider, and 35 is the first level on which Keystore2 enforces the
+  # MGF1 digest against the key's authorised set. The pre-M KeyPairGeneratorSpec
+  # branch (API 21-22) is not covered here. Dropping any of these levels silently
+  # re-opens the MGF1 regression that shipped broken in v1.77.0.
+  encryption:
+    strategy:
+      fail-fast: false
+      matrix:
+        api-level: [25, 30, 35]
+    name: Instrumented tests (API ${{ matrix.api-level }})
+    if: github.event_name != 'pull_request' || github.event.pull_request.draft == false
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Setup JAVA 17
+        uses: actions/setup-java@v3
+        with:
+          distribution: "temurin"
+          java-version: 17
+
+      - name: Cache Gradle and wrapper
+        uses: actions/cache@v3
+        with:
+          path: |
+            ~/.gradle/caches
+            ~/.gradle/wrapper
+          key: ${{ runner.os }}-gradle-${{ hashFiles('**/*.gradle*') }}
+
+      - name: Setup Google Services
+        run: echo ${{ secrets.GOOGLE_SERVICES_JSON }} | base64 --decode > ./app/google-services.json
+
+      - name: Grant KVM
+        run: |
+          echo 'KERNEL=="kvm", GROUP="kvm", MODE="0666", OPTIONS+="static_node=kvm"' \
+            | sudo tee /etc/udev/rules.d/99-kvm4all.rules
+          sudo udevadm control --reload-rules
+          sudo udevadm trigger --name-match=kvm
+
+      # Run via `am instrument` rather than `connectedDebugAndroidTest`: the Unified
+      # Test Platform launcher bundled with AGP 8.1.2 throws a protobuf
+      # IllegalAccessError while parsing the device's AppProcessesProto on API 35,
+      # aborting the run with "0 tests" / INSTRUMENTATION_FAILED. Direct
+      # instrumentation is unaffected.
+      - name: Run instrumented tests
+        uses: reactivecircus/android-emulator-runner@v2
+        with:
+          api-level: ${{ matrix.api-level }}
+          arch: x86_64
+          disable-animations: true
+          emulator-options: -no-window -gpu swiftshader_indirect -noaudio -no-boot-anim -camera-back none
+          script: |
+            ./gradlew :app:assembleDebug :app:assembleDebugAndroidTest
+            adb install -r app/build/outputs/apk/debug/app-debug.apk
+            adb install -r app/build/outputs/apk/androidTest/debug/app-debug-androidTest.apk
+            adb shell am instrument -w me.capcom.smsgateway.test/androidx.test.runner.AndroidJUnitRunner | tee instrumented-output.txt
+            if ! grep -qE "OK \([1-9][0-9]* tests?\)" instrumented-output.txt || grep -q "FAILURES!!!" instrumented-output.txt; then adb logcat -d > logcat.txt; exit 1; fi
+
+      - name: Upload test report
+        if: failure()
+        uses: actions/upload-artifact@v4
+        with:
+          name: instrumented-test-report-api-${{ matrix.api-level }}
+          path: |
+            instrumented-output.txt
+            logcat.txt
+          if-no-files-found: ignore
+          retention-days: 7

app/src/androidTest/java/me/capcom/smsgateway/modules/encryption/providers/LegacyPassphraseEncryptionProviderTest.kt

@@ -64,7 +64,7 @@ class LegacyPassphraseEncryptionProviderTest {
             var thrown = false
             try {
                 legacy.decrypt(hardenedOutput)
-            } catch (e: RuntimeException) {
+            } catch (e: Exception) {
                 thrown = true
             }
             assertTrue("legacy provider must reject hardened (4-chunk) output", thrown)

app/src/main/java/me/capcom/smsgateway/modules/encryption/providers/RSAEncryptionProvider.kt

@@ -33,9 +33,9 @@ class RSAEncryptionProvider(
             Cipher.ENCRYPT_MODE,
             publicKey,
             OAEPParameterSpec(
-                "SHA-256",
+                OAEP_DIGEST,
                 "MGF1",
-                MGF1ParameterSpec.SHA256,
+                MGF1_DIGEST,
                 PSource.PSpecified.DEFAULT,
             ),
         )
@@ -89,9 +89,9 @@ class RSAEncryptionProvider(
             Cipher.DECRYPT_MODE,
             privateKey,
             OAEPParameterSpec(
-                "SHA-256",
+                OAEP_DIGEST,
                 "MGF1",
-                MGF1ParameterSpec.SHA256,
+                MGF1_DIGEST,
                 PSource.PSpecified.DEFAULT,
             ),
         )
@@ -116,5 +116,20 @@ class RSAEncryptionProvider(
         private const val AES_ALGORITHM = "AES"
         private const val RSA_OAEP_ALGORITHM = "RSA/ECB/OAEPWithSHA-256AndMGF1Padding"
         private const val AES_GCM_ALGORITHM = "AES/GCM/NoPadding"
+
+        /**
+         * MGF1 is deliberately SHA-1, not SHA-256, on every API level.
+         *
+         * Android Keystore authorizes only SHA-1 for MGF1 unless the key is generated
+         * with [android.security.keystore.KeyGenParameterSpec.Builder.setMgf1Digests],
+         * which is API 35+ only. Requesting MGF1-SHA-256 against a Keystore-backed key
+         * therefore fails on both sides of that boundary: below API 35 the provider
+         * rejects it with `InvalidAlgorithmParameterException: Unsupported MGF1 digest:
+         * SHA-256. Only SHA-1 supported`, and on API 35+ Keystore2 rejects it with
+         * `KeyStoreException: INCOMPATIBLE_MGF_DIGEST`. The OAEP digest itself stays
+         * SHA-256. Any change here must keep encrypt and decrypt on the same constant.
+         */
+        private const val OAEP_DIGEST = "SHA-256"
+        private val MGF1_DIGEST = MGF1ParameterSpec.SHA1
     }
 }