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:0e371afb3000c499e0781168ec881a47eab93bad)
Merged-In: Ide65205b83063801971c5778af3154bcf3f0e530
Change-Id: Ide65205b83063801971c5778af3154bcf3f0e530

1 files changed, 23 insertions, 9 deletions

diff --git a/core/java/android/database/DatabaseUtils.java b/core/java/android/database/DatabaseUtils.java
index 6c8a8500e4e3..d41df4f49d48 100644
--- a/core/java/android/database/DatabaseUtils.java
+++ b/core/java/android/database/DatabaseUtils.java
@@ -511,17 +511,31 @@ 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('\'');
     }