=== modified file 'src/com/mysql/jdbc/PreparedStatement.java'
--- src/com/mysql/jdbc/PreparedStatement.java	2009-01-23 18:21:18 +0000
+++ src/com/mysql/jdbc/PreparedStatement.java	2009-02-23 22:02:13 +0000
@@ -36,6 +36,10 @@
 import java.math.BigDecimal;
 import java.math.BigInteger;
 import java.net.URL;
+import java.nio.ByteBuffer;
+import java.nio.CharBuffer;
+import java.nio.charset.Charset;
+import java.nio.charset.CharsetEncoder;
 import java.sql.Array;
 import java.sql.Clob;
 import java.sql.Date;
@@ -54,10 +58,8 @@
 import java.util.Locale;
 import java.util.TimeZone;
 
-import com.mysql.jdbc.exceptions.DeadlockTimeoutRollbackMarker;
 import com.mysql.jdbc.exceptions.MySQLStatementCancelledException;
 import com.mysql.jdbc.exceptions.MySQLTimeoutException;
-import com.mysql.jdbc.exceptions.MySQLTransactionRollbackException;
 import com.mysql.jdbc.profiler.ProfilerEvent;
 
 /**
@@ -528,6 +530,9 @@
 	
 	private boolean compensateForOnDuplicateKeyUpdate = false;
 	
+	/** Charset encoder used to test if escaping is needed, such as Yen sign in SJIS */
+	private CharsetEncoder charsetEncoder;
+	
 	/**
 	 * Creates a prepared statement instance -- We need to provide factory-style
 	 * methods so we can support both JDBC3 (and older) and JDBC4 runtimes,
@@ -638,6 +643,8 @@
 		initializeFromParseInfo();
 		
 		this.compensateForOnDuplicateKeyUpdate = this.connection.getCompensateOnDuplicateKeyUpdateCounts();
+		
+		charsetEncoder = getEscapingCharsetEncoder(conn.getEncoding());
 	}
 
 	/**
@@ -677,6 +684,39 @@
 		initializeFromParseInfo();
 		
 		this.compensateForOnDuplicateKeyUpdate = this.connection.getCompensateOnDuplicateKeyUpdateCounts();
+
+		charsetEncoder = getEscapingCharsetEncoder(conn.getEncoding());
+	}
+	
+	/**
+	 * Get a CharsetEncoder if one is needed for escaping codepoints that are
+	 * transformed to backslash (0x5c) in the given encoding.
+	 * @param encoding The destination encoding
+	 * @return A CharsetEncoder if applicable, null otherwise.
+	 */
+	private CharsetEncoder getEscapingCharsetEncoder(String encoding) {
+		CharsetEncoder enc = Charset.forName(encoding).newEncoder();
+		CharBuffer cbuf = CharBuffer.allocate(1);
+		ByteBuffer bbuf = ByteBuffer.allocate(1);
+		
+		cbuf.put("\u00a5");
+		cbuf.position(0);
+		enc.encode(cbuf, bbuf, true);
+		if(bbuf.get(0) == '\\') {
+			return enc;
+		}
+		
+		cbuf.clear();
+		bbuf.clear();
+		
+		cbuf.put("\u20a9");
+		cbuf.position(0);
+		enc.encode(cbuf, bbuf, true);
+		if(bbuf.get(0) == '\\') {
+			return enc;
+		}
+			
+		return null;
 	}
 
 	/**
@@ -4131,6 +4171,20 @@
 	
 						break;
 	
+					case '\u00a5':
+					case '\u20a9':
+						// escape characters interpreted as backslash by mysql
+						if(charsetEncoder != null) {
+							CharBuffer cbuf = CharBuffer.allocate(1);
+							ByteBuffer bbuf = ByteBuffer.allocate(1); 
+							cbuf.put(c);
+							cbuf.position(0);
+							charsetEncoder.encode(cbuf, bbuf, true);
+							if(bbuf.get(0) == '\\') {
+								buf.append('\\');
+							}
+						}
+						// fall through
 					default:
 						buf.append(c);
 					}

=== modified file 'src/testsuite/regression/StatementRegressionTest.java'
--- src/testsuite/regression/StatementRegressionTest.java	2009-02-02 17:00:13 +0000
+++ src/testsuite/regression/StatementRegressionTest.java	2009-02-22 23:11:19 +0000
@@ -5825,4 +5825,28 @@
 			closeMemberJDBCResources();
 		}
 	}
+
+	/**
+	 * Bug #41730 - SQL Injection when using U+00A5 and SJIS/Windows-31J
+	 */
+	public void testBug41730() throws Exception {
+		Connection conn2 = null;
+		PreparedStatement pstmt2 = null;
+		try {
+			conn2 = getConnectionWithProps("characterEncoding=sjis");
+			pstmt2 = conn2.prepareStatement("select ?");
+			pstmt2.setString(1, "\u00A5'");
+			// this will throw an exception with a syntax error if it fails
+			pstmt2.executeQuery();
+		} finally {
+			try {
+				if(pstmt2 != null)
+					pstmt2.close();
+			} catch(SQLException ex) {}
+			try {
+				if(conn2 != null)
+					conn2.close();
+			} catch(SQLException ex) {}
+		}
+	}
  } 
\ No newline at end of file