vncviewer-android-patch.md

vncviewer-android-patch

This script patches VNC Viewer 3.7.1.44443.

Patches

• Fix double-backspace bug on certain keyboards (e.g. recent GBoard versions).
• Write all log messages to logcat (for debugging, since the default file log option doesn't include all log messages, e.g. key/mouse events).

Requirements

• Java 1.8+
• APKTool v2.5.0+
• Android Platform Tools 23+
  • apksigner
  • zipalign
• VNC Viewer 3.7.1.44443

vncviewer-android-patch.sh

#!/bin/bash
set -euo pipefail

JAVA="${JAVA:-java}"
ZIPALIGN="${ZIPALIGN:-zipalign}"
APKTOOL="${APKTOOL:-apktool.jar}"
APKSIGNER="${APKSIGNER:-apksigner.jar}"

if [[ "$#" -ne 2 ]] && [[ "$#" -ne 3 ]]; then
    echo "usage: $0 apk_orig apk_out [keystore]"
    echo
    echo "environment:"
    echo "  JAVA: ${JAVA}"
    echo "  ZIPALIGN: ${ZIPALIGN}"
    echo "  APKTOOL: ${APKTOOL}"
    echo "  APKSIGNER: ${APKSIGNER}"
    echo
    echo "note: developed for VNC Viewer 3.7.1.44443"
    exit 2
fi

APK_ORIG="$1"
APK_OUT="$2"
KEYSTORE="${3:-}"

if ! command -v "${ZIPALIGN}" &>/dev/null; then
    echo "Please install zipalign." 1>&2
    exit 1
fi

if ! command -v "${JAVA}" &>/dev/null; then
    echo "Please install Java." 1>&2
    exit 1
fi

if ! test -f "${APKTOOL}"; then
    echo "Please download APKTool v2.5.0 or newer." 1>&2
    exit 1
fi

if ! test -f "${APKSIGNER}"; then
    echo "Please download apksigner." 1>&2
    exit 1
fi

TMPDIR=".vncviewer-tmp"
rm -rf "${TMPDIR}"
mkdir "${TMPDIR}"

echo
echo '> Decompiling APK'
"${JAVA}" -jar "${APKTOOL}" d --no-res --output "${TMPDIR}/apk" "${APK_ORIG}"

echo
echo '> Patching APK :: Fix double-backspace bug'
patch -p1 -d "${TMPDIR}/apk" <<EOF
diff --git a/smali/com/realvnc/viewer/android/ui/input/f.smali b/smali/com/realvnc/viewer/android/ui/input/f.smali
index d72129f..d670d95 100644
--- a/smali/com/realvnc/viewer/android/ui/input/f.smali
+++ b/smali/com/realvnc/viewer/android/ui/input/f.smali
@@ -473,16 +473,6 @@
 
     if-ne v0, v2, :cond_11
 
-    .line 48
-    invoke-virtual {p1}, Landroid/view/KeyEvent;->getAction()I
-
-    move-result p1
-
-    if-ne p1, v1, :cond_12
-
-    .line 49
-    invoke-virtual {p0}, Lcom/realvnc/viewer/android/ui/input/f;->a()V
-
     goto :goto_7
 
     .line 50
EOF

echo
echo '> Patching APK :: Write all log messages to logcat'
if [[ "${DEBUG:-0}" -ne "1" ]]; then
    echo "disabled (set DEBUG=1 to enable)"
else
patch -p1 -d "${TMPDIR}/apk" <<EOF
diff --git a/smali/com/realvnc/viewer/android/app/w6/p.smali b/smali/com/realvnc/viewer/android/app/w6/p.smali
index 5b8fbbb..1b8d0c1 100644
--- a/smali/com/realvnc/viewer/android/app/w6/p.smali
+++ b/smali/com/realvnc/viewer/android/app/w6/p.smali
@@ -91,47 +91,8 @@
 
 .method public static declared-synchronized a(ILjava/lang/String;Ljava/lang/String;)V
     .locals 2
-
-    const-class v0, Lcom/realvnc/viewer/android/app/w6/p;
-
-    monitor-enter v0
-
-    .line 7
-    :try_start_0
-    new-instance v1, Ljava/lang/StringBuilder;
-
-    invoke-direct {v1}, Ljava/lang/StringBuilder;-><init>()V
-
-    invoke-virtual {v1, p2}, Ljava/lang/StringBuilder;->append(Ljava/lang/String;)Ljava/lang/StringBuilder;
-
-    const-string p2, ""
-
-    invoke-virtual {v1, p2}, Ljava/lang/StringBuilder;->append(Ljava/lang/String;)Ljava/lang/StringBuilder;
-
-    invoke-virtual {v1}, Ljava/lang/StringBuilder;->toString()Ljava/lang/String;
-
-    move-result-object p2
-
-    .line 8
-    new-instance v1, Lcom/realvnc/viewer/android/app/w6/o;
-
-    invoke-direct {v1, p0, p1, p2}, Lcom/realvnc/viewer/android/app/w6/o;-><init>(ILjava/lang/String;Ljava/lang/String;)V
-
-    invoke-static {v1}, Lcom/realvnc/viewer/android/model/e2;->a(Ljava/lang/Runnable;)Z
-    :try_end_0
-    .catchall {:try_start_0 .. :try_end_0} :catchall_0
-
-    .line 9
-    monitor-exit v0
-
+    invoke-static {p1, p2}, Landroid/util/Log;->e(Ljava/lang/String;Ljava/lang/String;)I
     return-void
-
-    :catchall_0
-    move-exception p0
-
-    monitor-exit v0
-
-    throw p0
 .end method
 
 .method public static a(Z)V
EOF
fi

echo
echo '> Building APK'
"${JAVA}" -jar "${APKTOOL}" b --no-res --output "${TMPDIR}/patched.apk" "${TMPDIR}/apk"

echo
echo '> Aligning APK'
"${ZIPALIGN}" -p 4 "${TMPDIR}/patched.apk" "${TMPDIR}/aligned.apk"

echo
echo '> Signing APK'
if [[ -z "${KEYSTORE}" ]]; then
    test -f "default.jks" || keytool -genkeypair -v -keystore "default.jks" -keyalg "RSA" -storepass "default" -alias "default" -dname "CN=VNCViewer-Android-Patch, OU=Unknown, O=Unknown, L=Unknown, ST=Unknown, C=CA"
    "${JAVA}" -jar "${APKSIGNER}" sign --min-sdk-version=23 --ks "default.jks" --ks-pass "pass:default" --pass-encoding utf-8 --out "${TMPDIR}/signed.apk" "${TMPDIR}/aligned.apk"
else
    "${JAVA}" -jar "${APKSIGNER}" sign --min-sdk-version=23 --ks "${KEYSTORE}" --out "${TMPDIR}/signed.apk" "${TMPDIR}/aligned.apk"
fi

echo
echo '> Cleanup'
mv "${TMPDIR}/signed.apk" "${APK_OUT}"
rm -rf "${TMPDIR}"

echo
echo "Successfully patched ${APK_OUT} from ${APK_ORIG}."
exit 0

For VNC Viewer 4.x, see https://github.com/pgaskin/vncpatch.