[
https://issues.apache.org/jira/browse/COMPRESS-244?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Nico Kruber updated COMPRESS-244:
---------------------------------
Description:
h2. Brief description
large values with a first byte indicating at least 4 additional bytes shift an
integer by at least 32bits thus leading to an overflow and an incorrect value -
the value needs to be casted to long before the bitshift!
(see the attached patch)
h2. Details from the 7z documentation
{quote}
{noformat}
UINT64 means real UINT64 encoded with the following scheme:
Size of encoding sequence depends from first byte:
First_Byte Extra_Bytes Value
(binary)
0xxxxxxx : ( xxxxxxx )
10xxxxxx BYTE y[1] : ( xxxxxx << (8 * 1)) + y
110xxxxx BYTE y[2] : ( xxxxx << (8 * 2)) + y
...
1111110x BYTE y[6] : ( x << (8 * 6)) + y
11111110 BYTE y[7] : y
11111111 BYTE y[8] : y
{noformat}
{quote}
was:
h2. Brief description
large values with a first byte indicating at least 4 additional bytes shift an
integer by at least 32bits thus leading to an overflow and an incorrect value -
the value needs to be casted to long before the bitshift!
h2. Patch
let me see whether I can attach the patch as a file, otherwise this is it,
inline:
{noformat}
diff -U 3 -H -d -r -N -x .git -x .svn --
commons-compress-1.6-src.orig/src/main/java/org/apache/commons/compress/archivers/sevenz/SevenZFile.java
commons-compress-1.6-src/src/main/java/org/apache/commons/compress/archivers/sevenz/SevenZFile.java
---
commons-compress-1.6-src.orig/src/main/java/org/apache/commons/compress/archivers/sevenz/SevenZFile.java
2013-11-25 12:32:22.051085223 +0100
+++
commons-compress-1.6-src/src/main/java/org/apache/commons/compress/archivers/sevenz/SevenZFile.java
2013-10-23 05:59:56.000000000 +0200
@@ -900,7 +900,7 @@
long value = 0;
for (int i = 0; i < 8; i++) {
if ((firstByte & mask) == 0) {
- return value | ((firstByte & (mask - 1)) << (8 * i));
+ return value | (((long) (firstByte & (mask - 1))) << (8 * i));
}
long nextByte = in.readUnsignedByte();
value |= (nextByte << (8 * i));
{noformat}
h2. Details from the 7z documentation
{quote}
{noformat}
UINT64 means real UINT64 encoded with the following scheme:
Size of encoding sequence depends from first byte:
First_Byte Extra_Bytes Value
(binary)
0xxxxxxx : ( xxxxxxx )
10xxxxxx BYTE y[1] : ( xxxxxx << (8 * 1)) + y
110xxxxx BYTE y[2] : ( xxxxx << (8 * 2)) + y
...
1111110x BYTE y[6] : ( x << (8 * 6)) + y
11111110 BYTE y[7] : y
11111111 BYTE y[8] : y
{noformat}
{quote}
> 7z reading of UINT64 data type is wrong for big values
> ------------------------------------------------------
>
> Key: COMPRESS-244
> URL: https://issues.apache.org/jira/browse/COMPRESS-244
> Project: Commons Compress
> Issue Type: Bug
> Components: Archivers
> Affects Versions: 1.6
> Reporter: Nico Kruber
> Labels: easyfix, patch
> Attachments: fix-readUint64-for-large-values.diff
>
>
> h2. Brief description
> large values with a first byte indicating at least 4 additional bytes shift
> an integer by at least 32bits thus leading to an overflow and an incorrect
> value - the value needs to be casted to long before the bitshift!
> (see the attached patch)
> h2. Details from the 7z documentation
> {quote}
> {noformat}
> UINT64 means real UINT64 encoded with the following scheme:
> Size of encoding sequence depends from first byte:
> First_Byte Extra_Bytes Value
> (binary)
> 0xxxxxxx : ( xxxxxxx )
> 10xxxxxx BYTE y[1] : ( xxxxxx << (8 * 1)) + y
> 110xxxxx BYTE y[2] : ( xxxxx << (8 * 2)) + y
> ...
> 1111110x BYTE y[6] : ( x << (8 * 6)) + y
> 11111110 BYTE y[7] : y
> 11111111 BYTE y[8] : y
> {noformat}
> {quote}
--
This message was sent by Atlassian JIRA
(v6.1#6144)
