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Bug ID: 6740544 mismatch of signed, unsigned values causes mmap failure
6740544 : mismatch of signed, unsigned values causes mmap failure

Details
Type:
Bug
Submit Date:
2008-08-22
Status:
Closed
Updated Date:
2010-04-02
Project Name:
JDK
Resolved Date:
2009-05-13
Component:
core-libs
OS:
generic
Sub-Component:
java.util.jar
CPU:
generic
Priority:
P3
Resolution:
Duplicate
Affected Versions:
6
Fixed Versions:

Related Reports
Duplicate:
JDK-4681995 - Add support for large (> 4GB) zip/jar files

Sub Tasks

Description
In zip_util.h, macros are defined to access header fields, e.g.
#define LG(b, n) (SH(b, n) | (SH(b, n+2) << 16))
...
#define ENDSIZ(b) LG(b, 12)	    /* central directory size */

These are used in zip_util.c, e.g.
    cenlen = ENDSIZ(endbuf);
    if (cenlen > endpos)
	ZIP_FORMAT_ERROR("invalid END header (bad central directory size)");

cenlen is declared as a jlong, which is signed.  If the value returned from ENDSIZ has the high order bit set, cenlen is negative, and definitely less than endpos.  The value of cenlen is used (indirectly) in a call to mmap, which results in

mmap failed for CEN and END part of zip file

Comments
EVALUATION

The LG micro has already been patched as

#define LG(b, n) ((SH(b, n) | (SH(b, n+2) << 16)) &0xffffffffUL)

in the work for #4681995(the > 4G zipfile support) to guarantee its "unsighen 32 -bit".

Tests show the latestest zip/jar works pretty well with 2G-4G zipfile (which fall in the range of this 32-bit signed and unsigned gap.

The fix for #6599383 ( > 2G zipfle) is also related, which has already been in 6ux and 7.

Closed as the "dup" of #4681995. (backport the LG micro part of the fix).
2009-05-13 
SUGGESTED FIX

Use unsigned values instead of signed where appropriate.
2008-08-22 
EVALUATION

Signed values are used in a few places where unsigned should be used.
2008-08-22


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