From d7090f3f738642ba443bdb944e9dccfa068fdf66 Mon Sep 17 00:00:00 2001
From: osm0sis <osm0sis@outlook.com>
Date: Mon, 8 Jan 2024 12:21:22 -0400
Subject: [PATCH] Use custom function to hack props without increasing prop
 change counter

- some apps were detecting tampered props from the increased prop_info serial counter using resetprop
- patching doesn't rely on magiskboot hexpatch so should work on KernelSU and APatch as well
- hopefully temporary until all root solutions adopt a patched system_properties repo to fix counters via resetprop
---
 module/common.sh       | 45 ++++++++++++++++++++++++++++++++++++++++++
 module/post-fs-data.sh | 18 +++--------------
 module/service.sh      | 18 +++--------------
 3 files changed, 51 insertions(+), 30 deletions(-)
 create mode 100644 module/common.sh

diff --git a/module/common.sh b/module/common.sh
new file mode 100644
index 0000000..3dd2d1c
--- /dev/null
+++ b/module/common.sh
@@ -0,0 +1,45 @@
+# resetprop_hexpatch [-f|--force] <prop name> <new value>
+resetprop_hexpatch() {
+    case "$1" in
+        -f|--force) local FORCE=1; shift;;
+    esac 
+
+    local NAME="$1"
+    local NEWVALUE="$2"
+    local CURVALUE="$(resetprop "$NAME")"
+
+    [ ! "$NEWVALUE" -o ! "$CURVALUE" ] && return 1
+    [ "$NEWVALUE" = "$CURVALUE" -a ! "$FORCE" ] && return 1
+
+    local NEWLEN=${#NEWVALUE}
+    local PROPFILE="/dev/__properties__/$(resetprop -Z "$NAME")"
+    local NAMEOFFSET=$(echo $(strings -t d "$PROPFILE" | grep "$NAME") | cut -d ' ' -f 1)
+
+    #<hex 2-byte change counter><flags byte><hex length of prop value><prop value + nul padding to 92 bytes><prop name>
+    local NEWHEX="$(printf '%02x' "$NEWLEN")$(printf "$NEWVALUE" | od -A n -t x1 -v | tr -d ' \n')$(printf "%$((92-NEWLEN))s" | sed 's/ /00/g')"
+
+    printf "Patch '$NAME' to '$NEWVALUE' in '$PROPFILE' @ 0x%08x -> \n[0000??$NEWHEX]\n" $((NAMEOFFSET-96))
+
+    echo -ne "\x00\x00" \
+        | dd obs=1 count=2 seek=$((NAMEOFFSET-96)) conv=notrunc of="$PROPFILE"
+    echo -ne "$(printf "$NEWHEX" | sed -e 's/.\{2\}/&\\x/g' -e 's/^/\\x/' -e 's/\\x$//')" \
+        | dd obs=1 count=93 seek=$((NAMEOFFSET-93)) conv=notrunc of="$PROPFILE"
+}
+
+# resetprop_if_diff <prop name> <expected value>
+resetprop_if_diff() {
+    local NAME="$1"
+    local EXPECTED="$2"
+    local CURRENT="$(resetprop "$NAME")"
+
+    [ -z "$CURRENT" ] || [ "$CURRENT" == "$EXPECTED" ] || resetprop_hexpatch "$NAME" "$EXPECTED"
+}
+
+# resetprop_if_match <prop name> <value match string> <new value>
+resetprop_if_match() {
+    local NAME="$1"
+    local CONTAINS="$2"
+    local VALUE="$3"
+
+    [[ "$(resetprop "$NAME")" == *"$CONTAINS"* ]] && resetprop_hexpatch "$NAME" "$VALUE"
+}
diff --git a/module/post-fs-data.sh b/module/post-fs-data.sh
index f19aae2..2129668 100644
--- a/module/post-fs-data.sh
+++ b/module/post-fs-data.sh
@@ -1,3 +1,6 @@
+MODDIR="${0%/*}"
+. "$MODDIR/common.sh"
+
 # Remove Play Services from Magisk Denylist when set to enforcing
 if magisk --denylist status; then
     magisk --denylist rm com.google.android.gms
@@ -10,21 +13,6 @@ fi
 
 # Conditional early sensitive properties
 
-resetprop_if_diff() {
-    local NAME=$1
-    local EXPECTED=$2
-    local CURRENT=$(resetprop $NAME)
-
-    [ -z "$CURRENT" ] || [ "$CURRENT" == "$EXPECTED" ] || resetprop $NAME $EXPECTED
-}
-resetprop_if_match() {
-    local NAME=$1
-    local CONTAINS=$2
-    local VALUE=$3
-
-    [[ "$(resetprop $NAME)" == *"$CONTAINS"* ]] && resetprop $NAME $VALUE
-}
-
 # RootBeer, Microsoft
 resetprop_if_diff ro.build.tags release-keys
 
diff --git a/module/service.sh b/module/service.sh
index 5cf3d4b..6a02e95 100644
--- a/module/service.sh
+++ b/module/service.sh
@@ -1,20 +1,8 @@
+MODDIR="${0%/*}"
+. "$MODDIR/common.sh"
+
 # Conditional sensitive properties
 
-resetprop_if_diff() {
-    local NAME=$1
-    local EXPECTED=$2
-    local CURRENT=$(resetprop $NAME)
-
-    [ -z "$CURRENT" ] || [ "$CURRENT" == "$EXPECTED" ] || resetprop $NAME $EXPECTED
-}
-resetprop_if_match() {
-    local NAME=$1
-    local CONTAINS=$2
-    local VALUE=$3
-
-    [[ "$(resetprop $NAME)" == *"$CONTAINS"* ]] && resetprop $NAME $VALUE
-}
-
 # Magisk recovery mode
 resetprop_if_match ro.bootmode recovery unknown
 resetprop_if_match ro.boot.mode recovery unknown