RFR: JDK-8222187: java.util.Base64.Decoder stream adds unexpected null bytes at the end

Raffaello Giulietti raffaello.giulietti at gmail.com
Thu Jul 23 14:44:53 UTC 2020


Thanks for pushing changeset 865b5ca81009.
Raffaello



On 2020-07-21 19:18, Lance Andersen wrote:
> Hi Roger,
> 
> I will plan to push tomorrow morning pending any last minute reviews
> 
> Best
> Lance
> 
>> On Jul 21, 2020, at 9:57 AM, Roger Riggs <Roger.Riggs at oracle.com 
>> <mailto:Roger.Riggs at oracle.com>> wrote:
>>
>> Hi Rafaello, Lance,
>>
>> That looks good to me.
>>
>> Thanks, Roger
>>
>> On 7/19/20 2:31 PM, Lance Andersen wrote:
>>> Hi Raffaello,
>>>
>>> I think the changes look reasonable.
>>>
>>> I have created a webrev, 
>>> http://cr.openjdk.java.net/~lancea/8222187/webrev.00/, for others to 
>>> review as it is a bit easier than the patch.
>>>
>>> I have also run the JCK tests in this area as well as mach5 tiers1-3 
>>> (which I believe Roger has also)
>>>
>>> Best
>>> Lance
>>>
>>>> On Jul 15, 2020, at 5:44 PM, Raffaello Giulietti 
>>>> <raffaello.giulietti at gmail.com 
>>>> <mailto:raffaello.giulietti at gmail.com>> wrote:
>>>>
>>>> Hi Roger,
>>>>
>>>> On 2020-07-15 22:21, Roger Riggs wrote:
>>>>> Hi Raffaello,
>>>>> Base64.java:
>>>>> 2: Please update 2nd copyright year to 2020
>>>>
>>>> I was unsure what to do here, thanks for guidance.
>>>> I also removed the seemingly useless import at former L33.
>>>>
>>>>
>>>>
>>>>> leftovers():
>>>>> 996: "&" the shortcutting && is more typical in a condition.
>>>>> 997: the -= is buried in an expression and a reader might miss it.
>>>>
>>>> Corrected, as well as the analogous -= usage for wpos now at L1106-7
>>>>
>>>>
>>>>> 1053:  "can be reallocated to other vars":  not a useful comment, 
>>>>> reflecting on only one possible implementation that is out of the 
>>>>> control of the developer.
>>>>> I'd almost rather see 'len' than 'limit - off'; it might be 
>>>>> informative to the reader if 'limit' was declared final. (1056:)
>>>>
>>>> Done, as well as declaring i and v final in the loop.
>>>>
>>>>
>>>>
>>>>> TestBase54.java:
>>>>> 2: Update 2nd copyright year to 2020
>>>>> 27:  Please add the bug number to the @bug line.
>>>>> Style-wise, I would remove the blank lines at the beginning of 
>>>>> blocks. (1095, 1115)
>>>>
>>>> Done.
>>>>
>>>>
>>>>> Thanks, Roger
>>>>> On 7/14/20 11:47 AM, Raffaello Giulietti wrote:
>>>>>> Hi Roger,
>>>>>>
>>>>>> here's the latest version of the patch.
>>>>>>
>>>>>> I did:
>>>>>> * Withdraw the simplification in encodedOutLength(), as it is 
>>>>>> indeed out of scope for this bug fix.
>>>>>> * Restore field names in DecInputStream except for nextin (now 
>>>>>> wpos) and nextout (now rpos) because they have slightly different 
>>>>>> semantics. That's just for clarity. I would have nothing against 
>>>>>> reusing the old names for the proposed purpose.
>>>>>> * Switch back to the original no-arg read() implementation.
>>>>>> * Adjust comment continuation lines.
>>>>>> * Preserve the proposed logic of read(byte[], int, int) and the 
>>>>>> supporting methods.
>>>>>>
>>>>>> Others needed changes are:
>>>>>> * Correct the copyright years: that's something better left to Oracle.
>>>>>> * Remove the apparently useless import at L33. I could build and 
>>>>>> run without it.
>>>>>>
>>>>>>
>>>>>> Greetings
>>>>>> Raffaello
>>>>>>
>>>>
>>>>
>>>> ----
>>>>
>>>> # HG changeset patch
>>>> # User lello
>>>> # Date 1594848775 -7200
>>>> #      Wed Jul 15 23:32:55 2020 +0200
>>>> # Node ID f7407f35e83ab508f0e6deab4f776bb1a1c85e68
>>>> # Parent  a5649ebf94193770ca763391dd63807059d333b4
>>>> 8222187: java.util.Base64.Decoder stream adds unexpected null bytes 
>>>> at the end
>>>> Reviewed-by: TBD
>>>> Contributed-by: Raffaello Giulietti <raffaello.giulietti at gmail.com 
>>>> <mailto:raffaello.giulietti at gmail.com>>
>>>>
>>>> diff --git a/src/java.base/share/classes/java/util/Base64.java 
>>>> b/src/java.base/share/classes/java/util/Base64.java
>>>> --- a/src/java.base/share/classes/java/util/Base64.java
>>>> +++ b/src/java.base/share/classes/java/util/Base64.java
>>>> @@ -1,5 +1,5 @@
>>>> /*
>>>> - * Copyright (c) 2012, 2019, Oracle and/or its affiliates. All 
>>>> rights reserved.
>>>> + * Copyright (c) 2012, 2020, Oracle and/or its affiliates. All 
>>>> rights reserved.
>>>>  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
>>>>  *
>>>>  * This code is free software; you can redistribute it and/or modify it
>>>> @@ -30,7 +30,6 @@
>>>> import java.io.IOException;
>>>> import java.io.OutputStream;
>>>> import java.nio.ByteBuffer;
>>>> -import java.nio.charset.StandardCharsets;
>>>>
>>>> import sun.nio.cs.ISO_8859_1;
>>>>
>>>> @@ -961,12 +960,15 @@
>>>>
>>>>         private final InputStream is;
>>>>         private final boolean isMIME;
>>>> -        private final int[] base64;      // base64 -> byte mapping
>>>> -        private int bits = 0;            // 24-bit buffer for decoding
>>>> -        private int nextin = 18;         // next available "off" in 
>>>> "bits" for input;
>>>> -                                         // -> 18, 12, 6, 0
>>>> -        private int nextout = -8;        // next available "off" in 
>>>> "bits" for output;
>>>> -                                         // -> 8, 0, -8 (no byte 
>>>> for output)
>>>> +        private final int[] base64;     // base64 -> byte mapping
>>>> +        private int bits = 0;           // 24-bit buffer for decoding
>>>> +
>>>> +        /* writing bit pos inside bits; one of 24 (left, msb), 18, 
>>>> 12, 6, 0 */
>>>> +        private int wpos = 0;
>>>> +
>>>> +        /* reading bit pos inside bits: one of 24 (left, msb), 16, 
>>>> 8, 0 */
>>>> +        private int rpos = 0;
>>>> +
>>>>         private boolean eof = false;
>>>>         private boolean closed = false;
>>>>
>>>> @@ -983,107 +985,153 @@
>>>>             return read(sbBuf, 0, 1) == -1 ? -1 : sbBuf[0] & 0xff;
>>>>         }
>>>>
>>>> -        private int eof(byte[] b, int off, int len, int oldOff)
>>>> -            throws IOException
>>>> -        {
>>>> +        private int leftovers(byte[] b, int off, int pos, int limit) {
>>>>             eof = true;
>>>> -            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 == '=' below
>>>> -                b[off++] = (byte)(bits >> (16));
>>>> -                if (nextin == 0) {           // only one padding byte
>>>> -                    if (len == 1) {          // no enough output space
>>>> -                        bits >>= 8;          // shift to lowest byte
>>>> -                        nextout = 0;
>>>> -                    } else {
>>>> -                        b[off++] = (byte) (bits >>  8);
>>>> -                    }
>>>> -                }
>>>> +
>>>> +            /*
>>>> +             * We use a loop here, as this method is executed only 
>>>> a few times.
>>>> +             * Unrolling the loop would probably not contribute 
>>>> much here.
>>>> +             */
>>>> +            while (rpos - 8 >= wpos && pos != limit) {
>>>> +                rpos -= 8;
>>>> +                b[pos++] = (byte) (bits >> rpos);
>>>>             }
>>>> -            return off == oldOff ? -1 : off - oldOff;
>>>> +            return pos - off != 0 || rpos - 8 >= wpos ? pos - off : -1;
>>>>         }
>>>>
>>>> -        private int padding(byte[] b, int off, int len, int oldOff)
>>>> -            throws IOException
>>>> -        {
>>>> -            // =     shiftto==18 unnecessary padding
>>>> -            // x=    shiftto==12 dangling x, invalid unit
>>>> -            // xx=   shiftto==6 && missing last '='
>>>> -            // xx=y  or last is not '='
>>>> -            if (nextin == 18 || nextin == 12 ||
>>>> -                nextin == 6 && is.read() != '=') {
>>>> -                throw new IOException("Illegal base64 ending 
>>>> sequence:" + nextin);
>>>> +        private int eof(byte[] b, int off, int pos, int limit) 
>>>> throws IOException {
>>>> +            /*
>>>> +             * pos != limit
>>>> +             *
>>>> +             * wpos == 18: x     dangling single x, invalid unit
>>>> +             * accept ending xx or xxx without padding characters
>>>> +             */
>>>> +            if (wpos == 18) {
>>>> +                throw new IOException("Base64 stream has one 
>>>> un-decoded dangling byte.");
>>>>             }
>>>> -            b[off++] = (byte)(bits >> (16));
>>>> -            if (nextin == 0) {           // only one padding byte
>>>> -                if (len == 1) {          // no enough output space
>>>> -                    bits >>= 8;          // shift to lowest byte
>>>> -                    nextout = 0;
>>>> -                } else {
>>>> -                    b[off++] = (byte) (bits >>  8);
>>>> -                }
>>>> +            rpos = 24;
>>>> +            return leftovers(b, off, pos, limit);
>>>> +        }
>>>> +
>>>> +        private int padding(byte[] b, int off, int pos, int limit) 
>>>> throws IOException {
>>>> +            /*
>>>> +             * pos != limit
>>>> +             *
>>>> +             * wpos == 24: =    (unnecessary padding)
>>>> +             * wpos == 18: x=   (dangling single x, invalid unit)
>>>> +             * wpos == 12 and missing last '=': xx=  (invalid padding)
>>>> +             * wpos == 12 and last is not '=': xx=x (invalid padding)
>>>> +             */
>>>> +            if (wpos >= 18 || wpos == 12 && is.read() != '=') {
>>>> +                throw new IOException("Illegal base64 ending 
>>>> sequence:" + wpos);
>>>>             }
>>>> -            eof = true;
>>>> -            return off - oldOff;
>>>> +            rpos = 24;
>>>> +            return leftovers(b, off, pos, limit);
>>>>         }
>>>>
>>>>         @Override
>>>>         public int read(byte[] b, int off, int len) throws IOException {
>>>> -            if (closed)
>>>> +            if (closed) {
>>>>                 throw new IOException("Stream is closed");
>>>> -            if (eof && nextout < 0)    // eof and no leftover
>>>> -                return -1;
>>>> -            if (off < 0 || len < 0 || len > b.length - off)
>>>> -                throw new IndexOutOfBoundsException();
>>>> -            int oldOff = off;
>>>> -            while (nextout >= 0) {       // leftover output byte(s) 
>>>> in bits buf
>>>> -                if (len == 0)
>>>> -                    return off - oldOff;
>>>> -                b[off++] = (byte)(bits >> nextout);
>>>> -                len--;
>>>> -                nextout -= 8;
>>>> +            }
>>>> +            Objects.checkFromIndexSize(off, len, b.length);
>>>> +            if (len == 0) {
>>>> +                return 0;
>>>>             }
>>>> -            bits = 0;
>>>> -            while (len > 0) {
>>>> -                int v = is.read();
>>>> -                if (v == -1) {
>>>> -                    return eof(b, off, len, oldOff);
>>>> +
>>>> +            /*
>>>> +             * Rather than keeping 2 running vars (e.g., off and len),
>>>> +             * we only keep one (pos), while definitely fixing the 
>>>> boundaries
>>>> +             * of the range [off, limit).
>>>> +             * More specifically, each use of pos as an index in b 
>>>> meets
>>>> +             *      pos - off >= 0 & limit - pos > 0
>>>> +             *
>>>> +             * Note that limit can overflow to Integer.MIN_VALUE. 
>>>> However,
>>>> +             * as long as comparisons with pos are as coded, 
>>>> there's no harm.
>>>> +             */
>>>> +            int pos = off;
>>>> +            final int limit = off + len;
>>>> +            if (eof) {
>>>> +                return leftovers(b, off, pos, limit);
>>>> +            }
>>>> +
>>>> +            /*
>>>> +             * Leftovers from previous invocation; here, wpos = 0.
>>>> +             * There can be at most 2 leftover bytes (rpos <= 16).
>>>> +             * Further, b has at least one free place.
>>>> +             *
>>>> +             * The logic could be coded as a loop, (as in method 
>>>> leftovers())
>>>> +             * but the explicit "unrolling" makes it possible to 
>>>> generate
>>>> +             * better byte extraction code.
>>>> +             */
>>>> +            if (rpos == 16) {
>>>> +                b[pos++] = (byte) (bits >> 8);
>>>> +                rpos = 8;
>>>> +                if (pos == limit) {
>>>> +                    return len;
>>>>                 }
>>>> -                if ((v = base64[v]) < 0) {
>>>> -                    if (v == -2) {       // padding byte(s)
>>>> -                        return padding(b, off, len, oldOff);
>>>> -                    }
>>>> -                    if (v == -1) {
>>>> -                        if (!isMIME)
>>>> -                            throw new IOException("Illegal base64 
>>>> character " +
>>>> -                                Integer.toString(v, 16));
>>>> -                        continue;        // skip if for rfc2045
>>>> -                    }
>>>> -                    // neve be here
>>>> -                }
>>>> -                bits |= (v << nextin);
>>>> -                if (nextin == 0) {
>>>> -                    nextin = 18;         // clear for next in
>>>> -                    b[off++] = (byte)(bits >> 16);
>>>> -                    if (len == 1) {
>>>> -                        nextout = 8;    // 2 bytes left in bits
>>>> -                        break;
>>>> -                    }
>>>> -                    b[off++] = (byte)(bits >> 8);
>>>> -                    if (len == 2) {
>>>> -                        nextout = 0;    // 1 byte left in bits
>>>> -                        break;
>>>> -                    }
>>>> -                    b[off++] = (byte)bits;
>>>> -                    len -= 3;
>>>> -                    bits = 0;
>>>> -                } else {
>>>> -                    nextin -= 6;
>>>> +            }
>>>> +            if (rpos == 8) {
>>>> +                b[pos++] = (byte) bits;
>>>> +                rpos = 0;
>>>> +                if (pos == limit) {
>>>> +                    return len;
>>>>                 }
>>>>             }
>>>> -            return off - oldOff;
>>>> +
>>>> +            bits = 0;
>>>> +            wpos = 24;
>>>> +            for (;;) {
>>>> +                /* pos != limit & rpos == 0 */
>>>> +                final int i = is.read();
>>>> +                if (i < 0) {
>>>> +                    return eof(b, off, pos, limit);
>>>> +                }
>>>> +                final int v = base64[i];
>>>> +                if (v < 0) {
>>>> +                    /*
>>>> +                     * i not in alphabet, thus
>>>> +                     *      v == -2: i is '=', the padding
>>>> +                     *      v == -1: i is something else, typically 
>>>> CR or LF
>>>> +                     */
>>>> +                    if (v == -1) {
>>>> +                        if (isMIME) {
>>>> +                            continue;
>>>> +                        }
>>>> +                        throw new IOException("Illegal base64 
>>>> character 0x" +
>>>> +                                Integer.toHexString(i));
>>>> +                    }
>>>> +                    return padding(b, off, pos, limit);
>>>> +                }
>>>> +                wpos -= 6;
>>>> +                bits |= v << wpos;
>>>> +                if (wpos != 0) {
>>>> +                    continue;
>>>> +                }
>>>> +                if (limit - pos >= 3) {
>>>> +                    /* frequently taken fast path, no need to track 
>>>> rpos */
>>>> +                    b[pos++] = (byte) (bits >> 16);
>>>> +                    b[pos++] = (byte) (bits >> 8);
>>>> +                    b[pos++] = (byte) bits;
>>>> +                    bits = 0;
>>>> +                    wpos = 24;
>>>> +                    if (pos == limit) {
>>>> +                        return len;
>>>> +                    }
>>>> +                    continue;
>>>> +                }
>>>> +
>>>> +                /* b has either 1 or 2 free places */
>>>> +                b[pos++] = (byte) (bits >> 16);
>>>> +                if (pos == limit) {
>>>> +                    rpos = 16;
>>>> +                    return len;
>>>> +                }
>>>> +                b[pos++] = (byte) (bits >> 8);
>>>> +                /* pos == limit, no need for an if */
>>>> +                rpos = 8;
>>>> +                return len;
>>>> +            }
>>>>         }
>>>>
>>>>         @Override
>>>> diff --git a/test/jdk/java/util/Base64/TestBase64.java 
>>>> b/test/jdk/java/util/Base64/TestBase64.java
>>>> --- a/test/jdk/java/util/Base64/TestBase64.java
>>>> +++ b/test/jdk/java/util/Base64/TestBase64.java
>>>> @@ -1,5 +1,5 @@
>>>> /*
>>>> - * Copyright (c) 2012, 2017, Oracle and/or its affiliates. All 
>>>> rights reserved.
>>>> + * Copyright (c) 2012, 2020, Oracle and/or its affiliates. All 
>>>> rights reserved.
>>>>  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
>>>>  *
>>>>  * This code is free software; you can redistribute it and/or modify it
>>>> @@ -24,7 +24,7 @@
>>>> /**
>>>>  * @test
>>>>  * @bug 4235519 8004212 8005394 8007298 8006295 8006315 8006530 
>>>> 8007379 8008925
>>>> - *      8014217 8025003 8026330 8028397 8129544 8165243 8176379
>>>> + *      8014217 8025003 8026330 8028397 8129544 8165243 8176379 8222187
>>>>  * @summary tests java.util.Base64
>>>>  * @library /test/lib
>>>>  * @build jdk.test.lib.RandomFactory
>>>> @@ -144,6 +144,10 @@
>>>>         testDecoderKeepsAbstinence(Base64.getDecoder());
>>>>         testDecoderKeepsAbstinence(Base64.getUrlDecoder());
>>>>         testDecoderKeepsAbstinence(Base64.getMimeDecoder());
>>>> +
>>>> +        // tests patch addressing JDK-8222187
>>>> +        // https://bugs.openjdk.java.net/browse/JDK-8222187
>>>> +        testJDK_8222187();
>>>>     }
>>>>
>>>>     private static void test(Base64.Encoder enc, Base64.Decoder dec,
>>>> @@ -607,4 +611,26 @@
>>>>             }
>>>>         }
>>>>     }
>>>> +
>>>> +    private static void testJDK_8222187() throws Throwable {
>>>> +        byte[] orig = "12345678".getBytes("US-ASCII");
>>>> +        byte[] encoded = Base64.getEncoder().encode(orig);
>>>> +        // decode using different buffer sizes, up to a longer one 
>>>> than needed
>>>> +        for (int bufferSize = 1; bufferSize <= encoded.length + 1; 
>>>> bufferSize++) {
>>>> +            try (
>>>> +                    InputStream in = Base64.getDecoder().wrap(
>>>> +                            new ByteArrayInputStream(encoded));
>>>> +                    ByteArrayOutputStream baos = new 
>>>> ByteArrayOutputStream();
>>>> +            ) {
>>>> +                byte[] buffer = new byte[bufferSize];
>>>> +                int read;
>>>> +                while ((read = in.read(buffer, 0, bufferSize)) >= 0) {
>>>> +                    baos.write(buffer, 0, read);
>>>> +                }
>>>> +                // compare result, output info if lengths do not match
>>>> +                byte[] decoded = baos.toByteArray();
>>>> +                checkEqual(decoded, orig, "Base64 stream decoding 
>>>> failed!");
>>>> +            }
>>>> +        }
>>>> +    }
>>>> }
>>>> <JDK-8222187.patch>
>>>
>>> <oracle_sig_logo.gif> 
>>> <http://oracle.com/us/design/oracle-email-sig-198324.gif>
>>> <http://oracle.com/us/design/oracle-email-sig-198324.gif><http://oracle.com/us/design/oracle-email-sig-198324.gif>
>>> <http://oracle.com/us/design/oracle-email-sig-198324.gif>Lance 
>>> Andersen| Principal Member of Technical Staff | +1.781.442.2037
>>> Oracle Java Engineering
>>> 1 Network Drive
>>> Burlington, MA 01803
>>> Lance.Andersen at oracle.com <mailto:Lance.Andersen at oracle.com>
>>>
>>>
>>>
>>
> 
> 
> Best
> Lance
> ------------------
> 
> 
> 
> Lance Andersen| Principal Member of Technical Staff | +1.781.442.2037
> Oracle Java Engineering
> 1 Network Drive
> Burlington, MA 01803
> Lance.Andersen at oracle.com <mailto:Lance.Andersen at oracle.com>
> 
> 
> 
> 


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