95 lines
4.3 KiB
Plaintext
95 lines
4.3 KiB
Plaintext
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DOUBLEDOS - Unprotect
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Based on The Lone Victor's
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routine.
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The following instructions show you how to bypass the SoftGuard
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copy protection scheme used on DOUBLEDOS version 1.00. This is the same
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scheme used for FrameWork 1.10 and for Wordstar 2000 1.00. Wordstar
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2000 version 1.10 does not use a copy protection scheme, while versions
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1.00 of dBase III and FrameWork used ProLock. To unprotect Prolock disks
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read the file PROLOCK.UNP.
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First, using your valid, original DOUBLEDOS diskette, install it on
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a fixed disk. Softguard hides three files in your root directory:
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CML0200.HCL, VDF0200.VDW, and DOUBLEDO.EXE. It also copies DOUBLEDO.COM into
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your chosen DOUBLEDOS directory. DOUBLEDO.EXE is the real DOUBLEDOS program,
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encrypted. When you run DOUBLEDOS, the program DOUBLEDO.COM loads CML0200.HCL
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high in memory and runs it. CML decrypts itself and reads VDF0200.VDW.
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The VDF file contains some code and data from the fixed disk FAT at the
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time of installation. By comparing the information in the VDF file with
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the current FAT, CML can tell if the CML, VDF, and DOUBLEDO.EXE files are
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in the same place on the disk where they were installed. If they have
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moved, say from a backup & restore, then DOUBLEDOS will not run.
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Second, un-hide the three files in the root directory. You can do
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this with the programs ALTER.COM or FM.COM found on any BBS.
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Make copies of the three files, and of DOUBLEDO.COM, into some other
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directory.
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Hide the three root files again using ALTER or FM.
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Following the DOUBLEDOS instructions, UNINSTALL DOUBLEDOS. You can now
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put away your original DOUBLEDOS diskette. We are done with it.
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Next we will make some patches to CML0200.HCL to allow us to trace
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through the code in DEBUG. These patches will keep it from killing our
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interrupt vectors.
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debug cml0200.hcl
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e 3F9 <CR> 2A.4A <CR> ; change the 2A to 4A
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e 49D <CR> F6.16 <CR> ; if any of these numbers don't show up
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e 506 <CR> E9.09 <CR> ; it's not working.
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e A79 <CR> 00.20 <CR> ;
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e AE9 <CR> 00.20 <CR> ;
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e 73C 97 FA FA F4 F1 7E <CR> ; this is an encrypted call to 0:300
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w ; write out the new CML file
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q ; quit debug
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Now copy your four saved files back into the root directory and
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hide the CML0200.HCL, VDF0200.VDW, and DOUBLEDOS.EXE files using ALTER or FM.
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We can now run DOUBLEDO.COM using DEBUG, trace just up to the point
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where it has decrypted DOUBLEDO.EXE, then write that file out.
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debug dOUBLEDO.COM
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r <CR> ; write down the value of DS for use below.
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a 0:300 <CR> ; we must assemble some code here
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pop ax
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cs:
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mov [320],ax ; save return address
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pop ax
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cs:
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mov [322],ax
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push es ; set up stack the way we need it
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mov ax,20
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mov es,ax
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mov ax,0
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cs:
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jmp far ptr [320] ; jump to our return address
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<CR>
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g 406 ; now we can trace CML
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t
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g 177 ; this stuff just traces past some
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g 1E9 ; encryption routines.
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t
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g 54E ; wait while reading VDF & FAT
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g=559 569
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g=571 857 ; DOUBLEDO.EXE has been decrypted
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rBX <CR> ; length DOUBLEDO.EXE = 04800 bytes
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:0 ; set BX to 0
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rCX <CR>
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:4800 ; set CX to 4800.
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nDOUBLEDO ; name of file to write to
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w XXXX:100 ; where XXXX is the value of DS that
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; you wrote down at the begining.
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q ; quit debug
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Last, unhide and delete the three root files CML0200.HCL, VDF0200.VDW,
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and DOUBLEDO.EXE. Delete DOUBLEDO.COM and rename DOUBLEDO to DOUBLEDO.EXE. This is the
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real DOUBLEDOS program without any SoftGuard code or encryption. It requires
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only the DOUBLGD2.PGM and DDCONFIG.SYS files to run.
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