changeset 6543:e202f43a8b8a

8006295: Base64.Decoder.wrap(java.io.InputStream) returns InputStream which throws unspecified IOException on attempt to decode invalid Base64 byte stream 8006315: Base64.Decoder decoding methods are not consistent in treating non-padded data 8006530: Base64.getMimeDecoder().decode() throws exception for non-base64 character after adding = Summary: updated the spec to describe the expected behave explicitly and the implementation to follow Reviewed-by: alanb, chegar, lancea
author sherman
date Mon, 04 Feb 2013 11:58:43 -0800
parents 5bf1c9e6be60
children e04467fa13af 41654275896d
files src/share/classes/java/util/Base64.java test/java/util/Base64/TestBase64.java
diffstat 2 files changed, 161 insertions(+), 43 deletions(-) [+]
line wrap: on
line diff
--- a/src/share/classes/java/util/Base64.java	Mon Feb 04 17:20:26 2013 +0000
+++ b/src/share/classes/java/util/Base64.java	Mon Feb 04 11:58:43 2013 -0800
@@ -64,7 +64,8 @@
  *     RFC 2045 for encoding and decoding operation. The encoded output
  *     must be represented in lines of no more than 76 characters each
  *     and uses a carriage return {@code '\r'} followed immediately by
- *     a linefeed {@code '\n'} as the line separator. All line separators
+ *     a linefeed {@code '\n'} as the line separator. No line separator
+ *     is added to the end of the encoded output. All line separators
  *     or other characters not found in the base64 alphabet table are
  *     ignored in decoding operation.</p></li>
  * </ul>
@@ -614,6 +615,13 @@
      * This class implements a decoder for decoding byte data using the
      * Base64 encoding scheme as specified in RFC 4648 and RFC 2045.
      *
+     * <p> The Base64 padding character {@code '='} is accepted and
+     * interpreted as the end of the encoded byte data, but is not
+     * required. So if the final unit of the encoded byte data only has
+     * two or three Base64 characters (without the corresponding padding
+     * character(s) padded), they are decoded as if followed by padding
+     * character(s).
+     *
      * <p> Instances of {@link Decoder} class are safe for use by
      * multiple concurrent threads.
      *
@@ -857,6 +865,9 @@
         /**
          * Returns an input stream for decoding {@link Base64} encoded byte stream.
          *
+         * <p> The {@code read}  methods of the returned {@code InputStream} will
+         * throw {@code IOException} when reading bytes that cannot be decoded.
+         *
          * <p> Closing the returned input stream will close the underlying
          * input stream.
          *
@@ -883,13 +894,16 @@
             int    dl = dst.arrayOffset() + dst.limit();
             int    dp0 = dp;
             int    mark = sp;
-            boolean padding = false;
             try {
                 while (sp < sl) {
                     int b = sa[sp++] & 0xff;
                     if ((b = base64[b]) < 0) {
                         if (b == -2) {   // padding byte
-                            padding = true;
+                            if (shiftto == 6 && (sp == sl || sa[sp++] != '=') ||
+                                shiftto == 18) {
+                                throw new IllegalArgumentException(
+                                     "Input byte array has wrong 4-byte ending unit");
+                            }
                             break;
                         }
                         if (isMIME)     // skip if for rfc2045
@@ -915,24 +929,23 @@
                 if (shiftto == 6) {
                     if (dl - dp < 1)
                         return dp - dp0;
-                    if (padding && (sp + 1 != sl || sa[sp++] != '='))
-                        throw new IllegalArgumentException(
-                            "Input buffer has wrong 4-byte ending unit");
                     da[dp++] = (byte)(bits >> 16);
-                    mark = sp;
                 } else if (shiftto == 0) {
                     if (dl - dp < 2)
                         return dp - dp0;
-                    if (padding && sp != sl)
-                        throw new IllegalArgumentException(
-                            "Input buffer has wrong 4-byte ending unit");
                     da[dp++] = (byte)(bits >> 16);
                     da[dp++] = (byte)(bits >>  8);
-                    mark = sp;
-                } else if (padding || shiftto != 18) {
+                } else if (shiftto == 12) {
                     throw new IllegalArgumentException(
                         "Last unit does not have enough valid bits");
                 }
+                while (sp < sl) {
+                    if (isMIME && base64[sa[sp++]] < 0)
+                        continue;
+                    throw new IllegalArgumentException(
+                        "Input byte array has incorrect ending byte at " + sp);
+                }
+                mark = sp;
                 return dp - dp0;
             } finally {
                 src.position(mark);
@@ -950,14 +963,16 @@
             int    dl = dst.limit();
             int    dp0 = dp;
             int    mark = sp;
-            boolean padding = false;
-
             try {
                 while (sp < sl) {
                     int b = src.get(sp++) & 0xff;
                     if ((b = base64[b]) < 0) {
                         if (b == -2) {  // padding byte
-                            padding = true;
+                            if (shiftto == 6 && (sp == sl || src.get(sp++) != '=') ||
+                                shiftto == 18) {
+                                throw new IllegalArgumentException(
+                                     "Input byte array has wrong 4-byte ending unit");
+                            }
                             break;
                         }
                         if (isMIME)     // skip if for rfc2045
@@ -983,24 +998,23 @@
                 if (shiftto == 6) {
                     if (dl - dp < 1)
                         return dp - dp0;
-                    if (padding && (sp + 1 != sl || src.get(sp++) != '='))
-                        throw new IllegalArgumentException(
-                            "Input buffer has wrong 4-byte ending unit");
                      dst.put(dp++, (byte)(bits >> 16));
-                     mark = sp;
                 } else if (shiftto == 0) {
                     if (dl - dp < 2)
                         return dp - dp0;
-                    if (padding && sp != sl)
-                        throw new IllegalArgumentException(
-                            "Input buffer has wrong 4-byte ending unit");
                     dst.put(dp++, (byte)(bits >> 16));
                     dst.put(dp++, (byte)(bits >>  8));
-                    mark = sp;
-                } else if (padding || shiftto != 18) {
+                } else if (shiftto == 12) {
                     throw new IllegalArgumentException(
                         "Last unit does not have enough valid bits");
                 }
+                while (sp < sl) {
+                    if (isMIME && base64[src.get(sp++)] < 0)
+                        continue;
+                    throw new IllegalArgumentException(
+                        "Input byte array has incorrect ending byte at " + sp);
+                }
+                mark = sp;
                 return dp - dp0;
             } finally {
                 src.position(mark);
@@ -1048,12 +1062,20 @@
             int dp = 0;
             int bits = 0;
             int shiftto = 18;       // pos of first byte of 4-byte atom
-            boolean padding = false;
             while (sp < sl) {
                 int b = src[sp++] & 0xff;
                 if ((b = base64[b]) < 0) {
-                    if (b == -2) {     // padding byte
-                        padding = true;
+                    if (b == -2) {     // padding byte '='
+                        // xx=   shiftto==6&&sp==sl missing last =
+                        // xx=y  shiftto==6 last is not =
+                        // =     shiftto==18 unnecessary padding
+                        // x=    shiftto==12 be taken care later
+                        //       together with single x, invalid anyway
+                        if (shiftto == 6 && (sp == sl || src[sp++] != '=') ||
+                            shiftto == 18) {
+                            throw new IllegalArgumentException(
+                                "Input byte array has wrong 4-byte ending unit");
+                        }
                         break;
                     }
                     if (isMIME)    // skip if for rfc2045
@@ -1073,22 +1095,23 @@
                     bits = 0;
                 }
             }
-            // reach end of byte arry or hit padding '=' characters.
-            // if '=' presents, they must be the last one or two.
-            if (shiftto == 6) {           // xx==
-                if (padding && (sp + 1 != sl || src[sp] != '='))
-                    throw new IllegalArgumentException(
-                        "Input byte array has wrong 4-byte ending unit");
+            // reached end of byte array or hit padding '=' characters.
+            if (shiftto == 6) {
                 dst[dp++] = (byte)(bits >> 16);
-            } else if (shiftto == 0) {    // xxx=
-                if (padding && sp != sl)
-                    throw new IllegalArgumentException(
-                        "Input byte array has wrong 4-byte ending unit");
+            } else if (shiftto == 0) {
                 dst[dp++] = (byte)(bits >> 16);
                 dst[dp++] = (byte)(bits >>  8);
-            } else if (padding || shiftto != 18) {
-                    throw new IllegalArgumentException(
-                        "last unit does not have enough bytes");
+            } else if (shiftto == 12) {
+                throw new IllegalArgumentException(
+                    "Last unit does not have enough valid bits");
+            }
+            // anything left is invalid, if is not MIME.
+            // if MIME, ignore all non-base64 character
+            while (sp < sl) {
+                if (isMIME && base64[src[sp++]] < 0)
+                    continue;
+                throw new IllegalArgumentException(
+                    "Input byte array has incorrect ending byte at " + sp);
             }
             return dp;
         }
@@ -1252,8 +1275,22 @@
                 int v = is.read();
                 if (v == -1) {
                     eof = true;
-                    if (nextin != 18)
-                        throw new IOException("Base64 stream has un-decoded dangling byte(s).");
+                    if (nextin != 18) {
+                        if (nextin == 12)
+                            throw new IOException("Base64 stream has one un-decoded dangling byte.");
+                        // treat ending xx/xxx without padding character legal.
+                        // same logic as v == 'v' below
+                        b[off++] = (byte)(bits >> (16));
+                        len--;
+                        if (nextin == 0) {           // only one padding byte
+                            if (len == 0) {          // no enough output space
+                                bits >>= 8;          // shift to lowest byte
+                                nextout = 0;
+                            } else {
+                                b[off++] = (byte) (bits >>  8);
+                            }
+                        }
+                    }
                     if (off == oldOff)
                         return -1;
                     else
--- a/test/java/util/Base64/TestBase64.java	Mon Feb 04 17:20:26 2013 +0000
+++ b/test/java/util/Base64/TestBase64.java	Mon Feb 04 11:58:43 2013 -0800
@@ -22,7 +22,7 @@
  */
 
 /**
- * @test 4235519 8004212 8005394 8007298
+ * @test 4235519 8004212 8005394 8007298 8006295 8006315 8006530
  * @summary tests java.util.Base64
  */
 
@@ -112,6 +112,12 @@
 
         // test single-non-base64 character for mime decoding
         testSingleNonBase64MimeDec();
+
+        // test decoding of unpadded data
+        testDecodeUnpadded();
+
+        // test mime decoding with ignored character after padding
+        testDecodeIgnoredAfterPadding();
     }
 
     private static sun.misc.BASE64Encoder sunmisc = new sun.misc.BASE64Encoder();
@@ -359,6 +365,81 @@
         } catch (IllegalArgumentException iae) {}
     }
 
+    private static void testDecodeIgnoredAfterPadding() throws Throwable {
+        for (byte nonBase64 : new byte[] {'#', '(', '!', '\\', '-', '_', '\n', '\r'}) {
+            byte[][] src = new byte[][] {
+                "A".getBytes("ascii"),
+                "AB".getBytes("ascii"),
+                "ABC".getBytes("ascii"),
+                "ABCD".getBytes("ascii"),
+                "ABCDE".getBytes("ascii")
+            };
+            Base64.Encoder encM = Base64.getMimeEncoder();
+            Base64.Decoder decM = Base64.getMimeDecoder();
+            Base64.Encoder enc = Base64.getEncoder();
+            Base64.Decoder dec = Base64.getDecoder();
+            for (int i = 0; i < src.length; i++) {
+                // decode(byte[])
+                byte[] encoded = encM.encode(src[i]);
+                encoded = Arrays.copyOf(encoded, encoded.length + 1);
+                encoded[encoded.length - 1] = nonBase64;
+                checkEqual(decM.decode(encoded), src[i], "Non-base64 char is not ignored");
+                try {
+                    dec.decode(encoded);
+                    throw new RuntimeException("No IAE for non-base64 char");
+                } catch (IllegalArgumentException iae) {}
+
+                // decode(ByteBuffer[], ByteBuffer[])
+                ByteBuffer encodedBB = ByteBuffer.wrap(encoded);
+                ByteBuffer decodedBB = ByteBuffer.allocate(100);
+                int ret = decM.decode(encodedBB, decodedBB);
+                byte[] buf = new byte[ret];
+                decodedBB.flip();
+                decodedBB.get(buf);
+                checkEqual(buf, src[i], "Non-base64 char is not ignored");
+                try {
+                    encodedBB.rewind();
+                    decodedBB.clear();
+                    dec.decode(encodedBB, decodedBB);
+                    throw new RuntimeException("No IAE for non-base64 char");
+                } catch (IllegalArgumentException iae) {}
+                // direct
+                encodedBB.rewind();
+                decodedBB = ByteBuffer.allocateDirect(100);
+                ret = decM.decode(encodedBB, decodedBB);
+                buf = new byte[ret];
+                decodedBB.flip();
+                decodedBB.get(buf);
+                checkEqual(buf, src[i], "Non-base64 char is not ignored");
+                try {
+                    encodedBB.rewind();
+                    decodedBB.clear();
+                    dec.decode(encodedBB, decodedBB);
+                    throw new RuntimeException("No IAE for non-base64 char");
+                } catch (IllegalArgumentException iae) {}
+            }
+        }
+    }
+
+    private static void  testDecodeUnpadded() throws Throwable {
+        byte[] srcA = new byte[] { 'Q', 'Q' };
+        byte[] srcAA = new byte[] { 'Q', 'Q', 'E'};
+        Base64.Decoder dec = Base64.getDecoder();
+        byte[] ret = dec.decode(srcA);
+        if (ret[0] != 'A')
+            throw new RuntimeException("Decoding unpadding input A failed");
+        ret = dec.decode(srcAA);
+        if (ret[0] != 'A' && ret[1] != 'A')
+            throw new RuntimeException("Decoding unpadding input AA failed");
+        ret = new byte[10];
+        if (dec.wrap(new ByteArrayInputStream(srcA)).read(ret) != 1 &&
+            ret[0] != 'A')
+            throw new RuntimeException("Decoding unpadding input A from stream failed");
+        if (dec.wrap(new ByteArrayInputStream(srcA)).read(ret) != 2 &&
+            ret[0] != 'A' && ret[1] != 'A')
+            throw new RuntimeException("Decoding unpadding input AA from stream failed");
+    }
+
     // single-non-base64-char should be ignored for mime decoding, but
     // iae for basic decoding
     private static void testSingleNonBase64MimeDec() throws Throwable {