From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Kunal Malhotra <malhk@google.com>
Date: Fri, 2 Jun 2023 23:32:02 +0000
Subject: [PATCH] Fixing DatabaseUtils to detect malformed UTF-16 strings

Test: tested with POC in bug, also using atest
Bug: 224771621
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:fb4a72e3943d166088407e61aa4439ac349f3f12)
Merged-In: Ide65205b83063801971c5778af3154bcf3f0e530
Change-Id: Ide65205b83063801971c5778af3154bcf3f0e530
---
 core/java/android/database/DatabaseUtils.java | 32 +++++++++++++------
 1 file changed, 23 insertions(+), 9 deletions(-)

diff --git a/core/java/android/database/DatabaseUtils.java b/core/java/android/database/DatabaseUtils.java
index 992da312201d..53431a7414c4 100644
--- a/core/java/android/database/DatabaseUtils.java
+++ b/core/java/android/database/DatabaseUtils.java
@@ -429,17 +429,31 @@ public class DatabaseUtils {
      */
     public static void appendEscapedSQLString(StringBuilder sb, String sqlString) {
         sb.append('\'');
-        if (sqlString.indexOf('\'') != -1) {
-            int length = sqlString.length();
-            for (int i = 0; i < length; i++) {
-                char c = sqlString.charAt(i);
-                if (c == '\'') {
-                    sb.append('\'');
+        int length = sqlString.length();
+        for (int i = 0; i < length; i++) {
+            char c = sqlString.charAt(i);
+            if (Character.isHighSurrogate(c)) {
+                if (i == length - 1) {
+                    continue;
+                }
+                if (Character.isLowSurrogate(sqlString.charAt(i + 1))) {
+                    // add them both
+                    sb.append(c);
+                    sb.append(sqlString.charAt(i + 1));
+                    continue;
+                } else {
+                    // this is a lone surrogate, skip it
+                    continue;
                 }
-                sb.append(c);
             }
-        } else
-            sb.append(sqlString);
+            if (Character.isLowSurrogate(c)) {
+                continue;
+            }
+            if (c == '\'') {
+                sb.append('\'');
+            }
+            sb.append(c);
+        }
         sb.append('\'');
     }
 
