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minizip: Fix being unable to open empty zip file #778

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merged 1 commit into from
Jul 30, 2023
Merged

minizip: Fix being unable to open empty zip file #778

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48 changes: 26 additions & 22 deletions contrib/minizip/unzip.c
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Original file line number Diff line number Diff line change
Expand Up @@ -405,6 +405,10 @@ extern int ZEXPORT unzStringFileNameCompare (const char* fileName1,
#define BUFREADCOMMENT (0x400)
#endif

#ifndef CENTRALDIRINVALID
#define CENTRALDIRINVALID ((ZPOS64_T)(-1))
#endif

/*
Locate the Central directory of a zipfile (at the end, just before
the global comment)
Expand All @@ -416,10 +420,10 @@ local ZPOS64_T unz64local_SearchCentralDir(const zlib_filefunc64_32_def* pzlib_f
ZPOS64_T uSizeFile;
ZPOS64_T uBackRead;
ZPOS64_T uMaxBack=0xffff; /* maximum size of global comment */
ZPOS64_T uPosFound=0;
ZPOS64_T uPosFound=CENTRALDIRINVALID;

if (ZSEEK64(*pzlib_filefunc_def,filestream,0,ZLIB_FILEFUNC_SEEK_END) != 0)
return 0;
return CENTRALDIRINVALID;


uSizeFile = ZTELL64(*pzlib_filefunc_def,filestream);
Expand All @@ -429,7 +433,7 @@ local ZPOS64_T unz64local_SearchCentralDir(const zlib_filefunc64_32_def* pzlib_f

buf = (unsigned char*)ALLOC(BUFREADCOMMENT+4);
if (buf==NULL)
return 0;
return CENTRALDIRINVALID;

uBackRead = 4;
while (uBackRead<uMaxBack)
Expand Down Expand Up @@ -459,7 +463,7 @@ local ZPOS64_T unz64local_SearchCentralDir(const zlib_filefunc64_32_def* pzlib_f
break;
}

if (uPosFound!=0)
if (uPosFound!=CENTRALDIRINVALID)
break;
}
TRYFREE(buf);
Expand All @@ -482,12 +486,12 @@ local ZPOS64_T unz64local_SearchCentralDir64(const zlib_filefunc64_32_def* pzlib
ZPOS64_T uSizeFile;
ZPOS64_T uBackRead;
ZPOS64_T uMaxBack=0xffff; /* maximum size of global comment */
ZPOS64_T uPosFound=0;
ZPOS64_T uPosFound=CENTRALDIRINVALID;
uLong uL;
ZPOS64_T relativeOffset;

if (ZSEEK64(*pzlib_filefunc_def,filestream,0,ZLIB_FILEFUNC_SEEK_END) != 0)
return 0;
return CENTRALDIRINVALID;


uSizeFile = ZTELL64(*pzlib_filefunc_def,filestream);
Expand All @@ -497,7 +501,7 @@ local ZPOS64_T unz64local_SearchCentralDir64(const zlib_filefunc64_32_def* pzlib

buf = (unsigned char*)ALLOC(BUFREADCOMMENT+4);
if (buf==NULL)
return 0;
return CENTRALDIRINVALID;

uBackRead = 4;
while (uBackRead<uMaxBack)
Expand Down Expand Up @@ -527,47 +531,47 @@ local ZPOS64_T unz64local_SearchCentralDir64(const zlib_filefunc64_32_def* pzlib
break;
}

if (uPosFound!=0)
if (uPosFound!=CENTRALDIRINVALID)
break;
}
TRYFREE(buf);
if (uPosFound == 0)
return 0;
if (uPosFound == CENTRALDIRINVALID)
return CENTRALDIRINVALID;

/* Zip64 end of central directory locator */
if (ZSEEK64(*pzlib_filefunc_def,filestream, uPosFound,ZLIB_FILEFUNC_SEEK_SET)!=0)
return 0;
return CENTRALDIRINVALID;

/* the signature, already checked */
if (unz64local_getLong(pzlib_filefunc_def,filestream,&uL)!=UNZ_OK)
return 0;
return CENTRALDIRINVALID;

/* number of the disk with the start of the zip64 end of central directory */
if (unz64local_getLong(pzlib_filefunc_def,filestream,&uL)!=UNZ_OK)
return 0;
return CENTRALDIRINVALID;
if (uL != 0)
return 0;
return CENTRALDIRINVALID;

/* relative offset of the zip64 end of central directory record */
if (unz64local_getLong64(pzlib_filefunc_def,filestream,&relativeOffset)!=UNZ_OK)
return 0;
return CENTRALDIRINVALID;

/* total number of disks */
if (unz64local_getLong(pzlib_filefunc_def,filestream,&uL)!=UNZ_OK)
return 0;
return CENTRALDIRINVALID;
if (uL != 1)
return 0;
return CENTRALDIRINVALID;

/* Goto end of central directory record */
if (ZSEEK64(*pzlib_filefunc_def,filestream, relativeOffset,ZLIB_FILEFUNC_SEEK_SET)!=0)
return 0;
return CENTRALDIRINVALID;

/* the signature */
if (unz64local_getLong(pzlib_filefunc_def,filestream,&uL)!=UNZ_OK)
return 0;
return CENTRALDIRINVALID;

if (uL != 0x06064b50)
return 0;
return CENTRALDIRINVALID;

return relativeOffset;
}
Expand Down Expand Up @@ -621,7 +625,7 @@ local unzFile unzOpenInternal (const void *path,
return NULL;

central_pos = unz64local_SearchCentralDir64(&us.z_filefunc,us.filestream);
if (central_pos)
if (central_pos!=CENTRALDIRINVALID)
{
uLong uS;
ZPOS64_T uL64;
Expand Down Expand Up @@ -683,7 +687,7 @@ local unzFile unzOpenInternal (const void *path,
else
{
central_pos = unz64local_SearchCentralDir(&us.z_filefunc,us.filestream);
if (central_pos==0)
if (central_pos==CENTRALDIRINVALID)
err=UNZ_ERRNO;

us.isZip64 = 0;
Expand Down