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exeflat: store original ss:sp in UPX help data

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C. Masloch 2022-05-21 14:55:46 +02:00 committed by Kenneth J Davis
parent ad368a4420
commit 3b6d8362b3
1 changed files with 15 additions and 12 deletions
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27
utils/exeflat.c
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@ -375,25 +375,28 @@ static void write_trailer(FILE *dest, size_t size, int compress_sys_file,
0xAA, /* 15 stosb (store drive number)*/ 0xAA, /* 15 stosb (store drive number)*/
0x8B, 0xF7, /* 16 mov si,di */ 0x8B, 0xF7, /* 16 mov si,di */
0xF3, 0xA4, /* 18 rep movsb */ 0xF3, 0xA4, /* 18 rep movsb */
0x1E, /* 20 push ds */ 0x55, /* 20 push bp */
0x58, /* 21 pop ax */ 0x26, 0x8C, 0x16, 0x1E, 0x00, /* 21 mov word [es:(#32 - 2)], ss */
0x05, 0x00, 0x00, /* 22 add ax,... */ 0x26, 0x89, 0x26, 0x1C, 0x00, /* 26 mov word [es:(#32 - 4)], sp */
0x8E, 0xD0, /* 25 mov ss,ax */ 0x1E, /* 31 push ds */
0xBC, 0x00, 0x00, /* 27 mov sp,... */ 0x58, /* 32 pop ax */
0x31, 0xC0, /* 30 xor ax,ax */ 0x05, 0x00, 0x00, /* 33 add ax,... */
0xFF, 0xE0 /* 32 jmp ax */ 0x8E, 0xD0, /* 36 mov ss,ax */
0xBC, 0x00, 0x00, /* 38 mov sp,... */
0x31, 0xC0, /* 41 xor ax,ax */
0xFF, 0xE0 /* 43 jmp ax */
}; };
*(short *)&trailer[1] = (short)size + 0x20; *(short *)&trailer[1] = (short)size + 0x20;
*(short *)&trailer[23] = header->exInitSS; *(short *)&trailer[34] = header->exInitSS;
*(short *)&trailer[28] = header->exInitSP; *(short *)&trailer[39] = header->exInitSP;
if (compress_sys_file) { if (compress_sys_file) {
/* replace by jmp word ptr [6]: ff 26 06 00 /* replace by jmp word ptr [6]: ff 26 06 00
(the .SYS strategy handler which will unpack) */ (the .SYS strategy handler which will unpack) */
*(long *)&trailer[30] = 0x000626ffL; *(long *)&trailer[41] = 0x000626ffL;
/* set up a 4K stack for the UPX decompressor to work with */ /* set up a 4K stack for the UPX decompressor to work with */
*(short *)&trailer[23] = 0x1000; *(short *)&trailer[34] = 0x1000;
*(short *)&trailer[28] = 0x1000; *(short *)&trailer[39] = 0x1000;
} }
fwrite(trailer, 1, sizeof trailer, dest); fwrite(trailer, 1, sizeof trailer, dest);
} }