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https://issues.apache.org/jira/browse/COMPRESS-244?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Nico Kruber updated COMPRESS-244:
---------------------------------
Attachment: fix-readUint64-for-large-values.diff
this is the promised patch as a file
> 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!
> 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}
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