[jcifs] [Fwd: Your Report (Review ID: 254855) - Low-byte of Long Truncated Incorrectly by Bitwise AND]

[Michael B Allen]

---------------------------- Original Message ----------------------------
Subject: Your Report (Review ID: 254855) - Low-byte of Long Truncated
Incorrectly by Bitwise AND From:    "IncidentDaemon at sun.com"
<IncidentDaemon at sun.com>
Date:    Sun, April 18, 2004 8:58 pm
To:      mba2000 at ioplex.com
--------------------------------------------------------------------------

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dateCreated: Sun Apr 18 18:58:43 MDT 2004
type:        bug
cust_name:   Michael B Allen
cust_email:  mba2000 at ioplex.com
jdcid:       mike_allen3
status:      Waiting
category:    hotspot
subcategory: runtime_system
company:     JCIFS
release:     1.4.2
hardware:    x86
OSversion:   Linux
priority:    4
synopsis:    Low-byte of Long Truncated Incorrectly by Bitwise AND
description: FULL PRODUCT VERSION :
J2SE 1.4.2_04, 1.4.2_01, or 1.5Beta1

FULL OS VERSION :
RedHat 9 2.4.20
RedHat 7.3 2.4.18

A DESCRIPTION OF THE PROBLEM :
After running with -server flag for about a minute the following code
emits a value that has a low-byte of 0x00 regardless of the input:

     offset & 0xFFFFFFFFL

The specific context is found in the jCIFS SMB/CIFS client library
available at http://jcifs.samba.org/ version 0.8.2 or below
jcifs/smb/SmbComWriteAndX.java line ~87.

    writeInt4( offset & 0xFFFFFFFFL, dst, dstIndex );

where offset is a long and writeInt4 is:

    static void writeInt4( long val, byte[] dst, int dstIndex ) {
        dst[dstIndex++] = (byte)((int)(val >>> 0) & 0xFF);
        dst[dstIndex++] = (byte)((int)(val >>> 8) & 0xFF);
        dst[dstIndex++] = (byte)((int)(val >>> 16) & 0xFF);
        dst[dstIndex++] = (byte)((int)(val >>> 24) & 0xFF);
    }

Running without -server or removing the unnecessary mask solves the problem.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Download:

http://jcifs.samba.org/src/jcifs-0.8.21x.jar
http://home.comcast.net/~miallen1/jcifs/testjcifs.jar

And run like:

java -server -cp testjcifs.jar:jcifs-0.8.2x1.jar testjcifs.FullTest
smb://server/share/ dom\;user:pass 500

where server is a SMB/CIFS server. After approxamately 45 seconds the
output will transition as follows:

Thread-0 creating Z1082335691040.tmp
Thread-0 creating Z1082335691150.tmp
Thread-42 reading X1082335675290.tmp
Thread-0 creating Z1082335691440.tmp
clobbered: 0x5800
clobbered: 0x5800
clobbered: 0x5800
clobbered: 0x5800

This means that the offset field encoded into the SMB_COM_WRITE_ANDX
request with an FID of 0x5800 had the low byte "clobbered" to 0x00.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
The expression longValue & 0xFFFFFFFFL should not emit a value with a low
byte of 0x00 if the input longValue does not have a 0x00 low byte. ACTUAL
-
The expression longValue & 0xFFFFFFFFL emits a value with the low 8 byte
set to 0 regardless of whether or not the longValue has a non-0x00 low
byte.

REPRODUCIBILITY :
This bug can be reproduced always.

CUSTOMER SUBMITTED WORKAROUND :
Do not use the HotSpot -server option or do not mask a long value with
0xFFFFFFFFL in this way. workaround:
comments:    (company - JCIFS , email - mba2000 at ioplex.com)