diff --git a/kernel/kernel.asm b/kernel/kernel.asm index 77c6f8e..f613168 100644 --- a/kernel/kernel.asm +++ b/kernel/kernel.asm @@ -56,6 +56,7 @@ entry: ;************************************************************ global _LowKernelConfig _LowKernelConfig: +config_signature: db 'CONFIG' ; constant dw configend-configstart; size of config area ; to be checked !!! @@ -76,6 +77,9 @@ Version_Revision dw 41 ; REVISION_SEQ Version_Release dw 1 ; 0=release build, >0=svn# configend: +kernel_config_size: equ configend - config_signature + ; must be below-or-equal the size of struct _KernelConfig + ; in the file kconfig.h ! ;************************************************************ ; KERNEL CONFIGURATION AREA END @@ -94,7 +98,11 @@ configend: cpu 8086 ; (keep initial entry compatible) +global realentry realentry: ; execution continues here + clc ; this is patched to stc by exeflat + adc byte [cs:use_upx_config], 0 + ; ! ZF used later in kernel_start push ax push bx @@ -107,6 +115,9 @@ realentry: ; execution continues here pop ax jmp IGROUP:kernel_start + +use_upx_config: db 0 + beyond_entry: times 256-(beyond_entry-entry) db 0 ; scratch area for data (DOS_PSP) @@ -128,10 +139,51 @@ kernel_start: popf pop bx - mov ax,I_GROUP + +extern _kernel_command_line + + ; preserve unit in bl +init_command_line_buffer: + mov dx, I_GROUP + mov es, dx + mov ax, ss + mov ds, ax + mov ax, sp ; ds:ax = ss:sp + mov si, bp ; si = bp + jz .notupx ; ! ZF still left by adc + + xor ax, ax + mov ds, ax ; => UPX help data + lds si, [5E0h + 1Ch] ; -> original ss:sp - 2 + lea ax, [si + 2] ; ax = original sp + mov si, word [si] ; si = original bp + +.notupx: + cmp si, 114h + jb .none + cmp word [si - 14h], "CL" + jne .none + lea si, [si - 114h] ; -> command line buffer + cmp ax, si + ja .none + mov di, _kernel_command_line ; our buffer + mov cx, 255 + xor ax, ax + push di + rep movsb ; copy up to 255 bytes + stosb ; truncate + pop di + mov ch, 1 ; = 256 + repne scasb ; scan for terminator + rep stosb ; clear remainder of buffer + ; (make sure we do not have 0x00 0xFF + ; even if the command line given is + ; actually the empty string) +.none: + cli - mov ss,ax - mov sp,init_tos + mov ss, dx + mov sp, init_tos int 12h ; move init text+data to higher memory mov cl,6 shl ax,cl ; convert kb to para @@ -212,10 +264,40 @@ cont: ; Now set up call frame cpu XCPU %endif mov [_CPULevel], al - + + push ds + pop es mov ax,ss + +extern _debugger_present + mov bl, 1 + clc + int3 + jc .skip_ints_00_06 + xor bx, bx +.skip_ints_00_06: + mov byte [ss:_debugger_present], bl + +extern _InitKernelConfig + mov si, 60h + mov ds, si + mov si, _LowKernelConfig + cmp byte [use_upx_config], 0 + je .notupx + mov si, 5Eh + mov ds, si + mov si, 2 + mov bl, [0] + mov byte [es:_BootDrive], bl +.notupx: + mov es, ax + mov di, _InitKernelConfig + mov cx, kernel_config_size / 2 + rep movsw +%if kernel_config_size & 1 + movsb +%endif mov ds,ax - mov es,ax jmp _FreeDOSmain %if XCPU != 86 diff --git a/kernel/main.c b/kernel/main.c index f99492c..2b3f3c6 100644 --- a/kernel/main.c +++ b/kernel/main.c @@ -44,8 +44,6 @@ static char copyright[] = "GNU General Public License as published by the Free Software Foundation;\n" "either version 2, or (at your option) any later version.\n"; -struct _KernelConfig InitKernelConfig BSS_INIT({0}); - STATIC VOID InitIO(void); STATIC VOID update_dcb(struct dhdr FAR *); @@ -69,6 +67,11 @@ __segment DosTextSeg = 0; #endif struct lol FAR *LoL = &DATASTART; +struct _KernelConfig InitKernelConfig = { 0xFF }; +UBYTE kernel_command_line[256] = { 0x00, 0xFF }; /* special none value */ +UBYTE debugger_present = 0xFF; /* initialised in kernel.asm + do NOT set 0 here or compiler may + move it into bss that we zero out */ VOID ASMCFUNC FreeDOSmain(void) { @@ -92,17 +95,8 @@ VOID ASMCFUNC FreeDOSmain(void) drv = LoL->BootDrive + 1; p = MK_FP(0, 0x5e0); - if (fmemcmp(p+2,"CONFIG",6) == 0) /* UPX */ { - fmemcpy(&InitKernelConfig, p+2, sizeof(InitKernelConfig)); - - drv = *p + 1; - *(DWORD FAR *)(p+2) = 0; - } - else - { - *p = drv - 1; - fmemcpy(&InitKernelConfig, &LowKernelConfig, sizeof(InitKernelConfig)); + *p = drv - 1; /* compatibility with older kernels */ } if (drv >= 0x80) @@ -112,6 +106,12 @@ VOID ASMCFUNC FreeDOSmain(void) /* install DOS API and other interrupt service routines, basic kernel functionality works */ setup_int_vectors(); + if (kernel_command_line[0] == 0x00 && kernel_command_line[1] == 0xFF) { + printf("KERNEL: Command line is not specified.\n"); + } else { + printf("KERNEL: Command line is \"%s\"\n", kernel_command_line); + } + /* check if booting from floppy/CD */ CheckContinueBootFromHarddisk(); @@ -244,10 +244,10 @@ STATIC void setup_int_vectors(void) } vectors[] = { /* all of these are in the DOS DS */ - { 0x0, FP_OFF(int0_handler) }, /* zero divide */ - { 0x1, FP_OFF(empty_handler) }, /* single step */ - { 0x3, FP_OFF(empty_handler) }, /* debug breakpoint */ - { 0x6, FP_OFF(int6_handler) }, /* invalid opcode */ + { 0x80 | 0x0, FP_OFF(int0_handler) }, /* zero divide */ + { 0x80 | 0x1, FP_OFF(empty_handler) }, /* single step */ + { 0x80 | 0x3, FP_OFF(empty_handler) }, /* debug breakpoint */ + { 0x80 | 0x6, FP_OFF(int6_handler) }, /* invalid opcode */ { 0x19, FP_OFF(int19_handler) }, /* BIOS bootstrap loader, vdisk */ { 0x20, FP_OFF(int20_handler) }, { 0x21, FP_OFF(int21_handler) }, /* primary DOS API */ @@ -270,10 +270,11 @@ STATIC void setup_int_vectors(void) /* install default handlers */ for (i = 0x23; i <= 0x3f; i++) - setvec(i, empty_handler); + setvec(i, empty_handler); /* note: int 31h segment should be DOS DS */ HaltCpuWhileIdle = 0; for (pvec = vectors; pvec < vectors + (sizeof vectors/sizeof *pvec); pvec++) - setvec(pvec->intno, (intvec)MK_FP(FP_SEG(empty_handler), pvec->handleroff)); + if ((pvec->intno & 0x80) == 0 || debugger_present == 0) + setvec(pvec->intno & 0x7F, (intvec)MK_FP(FP_SEG(empty_handler), pvec->handleroff)); pokeb(0, 0x30 * 4, 0xea); pokel(0, 0x30 * 4 + 1, (ULONG)cpm_entry); diff --git a/utils/exeflat.c b/utils/exeflat.c index d055f98..7765d7e 100644 --- a/utils/exeflat.c +++ b/utils/exeflat.c @@ -54,6 +54,11 @@ large portions copied from task.c #define BUFSIZE 32768u #define KERNEL_START 0x16 /* the kernel code really starts here at 60:16 */ +#define KERNEL_CONFIG_LENGTH 32 - 2 - 4 + /* 32 entrypoint structure, + 2 entrypoint short jump, + 4 near jump / ss:sp storage */ +char kernel_config[KERNEL_CONFIG_LENGTH]; typedef struct { UWORD off, seg; @@ -85,7 +90,7 @@ static void usage(void) static int exeflat(const char *srcfile, const char *dstfile, const char *start, short *silentSegments, short silentcount, - int UPX, exe_header *header) + int UPX, int patchsignal, exe_header *header) { int i, j; size_t bufsize; @@ -94,6 +99,7 @@ static int exeflat(const char *srcfile, const char *dstfile, ULONG size, to_xfer; UBYTE **buffers; UBYTE **curbuf; + UBYTE *signal; FILE *src, *dest; short silentdone = 0; int compress_sys_file; @@ -199,6 +205,14 @@ static int exeflat(const char *srcfile, const char *dstfile, printf("\nProcessed %d relocations, %d not shown\n", header->exRelocItems, silentdone); + if (UPX) + { + struct x { + char y[(KERNEL_CONFIG_LENGTH + 2) <= BUFSIZE ? 1 : -1]; + }; + memcpy(kernel_config, &buffers[0][2], KERNEL_CONFIG_LENGTH); + } + realentry = KERNEL_START; if (buffers[0][0] == 0xeb /* jmp short */) { @@ -209,6 +223,31 @@ static int exeflat(const char *srcfile, const char *dstfile, realentry = ((UWORD)(buffers[0][2]) << 8) + buffers[0][1] + 3; } + signal = &buffers[(size_t)(realentry / BUFSIZE)][(size_t)(realentry % BUFSIZE)]; + if (patchsignal && UPX) + { + if (*signal == 0xF8) /* clc */ + { + *signal = 0xF9; /* stc */ + printf("Signal patched to indicate compression\n", dstfile); + } + else if (*signal == 0xF9) + { + printf("Signal is already patched to indicate compression\n", dstfile); + } + } + else if (patchsignal) + { + if (*signal == 0xF8) /* clc */ + { + printf("Signal not patched as no compression used\n", dstfile); + } + else if (*signal == 0xF9) + { + printf("Signal wrongly patched to indicate compression ??\n", dstfile); + } + } + if ((dest = fopen(dstfile, "wb+")) == NULL) { printf("Destination file %s could not be created\n", dstfile); @@ -289,6 +328,18 @@ static void write_header(FILE *dest, size_t size) 0xe9, 0, 0 /* 100: jmp 103 */ }; + if (0 == memcmp(kernel_config, "CONFIG", 6)) { + unsigned int length = kernel_config[6] + kernel_config[7] * 256U + 8; + if (length <= KERNEL_CONFIG_LENGTH) { + memcpy(&JumpBehindCode[2], kernel_config, length); + printf("Copied %u bytes of kernel config block to header\n", length); + } else { + printf("Error: Found %u bytes of kernel config block, too long!\n", length); + } + } else { + printf("Error: Found no kernel config block!\n"); + } + struct x { char y[sizeof(JumpBehindCode) == 0x20 ? 1 : -1]; }; @@ -324,25 +375,28 @@ static void write_trailer(FILE *dest, size_t size, int compress_sys_file, 0xAA, /* 15 stosb (store drive number)*/ 0x8B, 0xF7, /* 16 mov si,di */ 0xF3, 0xA4, /* 18 rep movsb */ - 0x1E, /* 20 push ds */ - 0x58, /* 21 pop ax */ - 0x05, 0x00, 0x00, /* 22 add ax,... */ - 0x8E, 0xD0, /* 25 mov ss,ax */ - 0xBC, 0x00, 0x00, /* 27 mov sp,... */ - 0x31, 0xC0, /* 30 xor ax,ax */ - 0xFF, 0xE0 /* 32 jmp ax */ +0x55, /* 20 push bp */ +0x26, 0x8C, 0x16, 0x1E, 0x00, /* 21 mov word [es:(#32 - 2)], ss */ +0x26, 0x89, 0x26, 0x1C, 0x00, /* 26 mov word [es:(#32 - 4)], sp */ + 0x1E, /* 31 push ds */ + 0x58, /* 32 pop ax */ + 0x05, 0x00, 0x00, /* 33 add 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[23] = header->exInitSS; - *(short *)&trailer[28] = header->exInitSP; + *(short *)&trailer[34] = header->exInitSS; + *(short *)&trailer[39] = header->exInitSP; if (compress_sys_file) { /* replace by jmp word ptr [6]: ff 26 06 00 (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 */ - *(short *)&trailer[23] = 0x1000; - *(short *)&trailer[28] = 0x1000; + *(short *)&trailer[34] = 0x1000; + *(short *)&trailer[39] = 0x1000; } fwrite(trailer, 1, sizeof trailer, dest); } @@ -398,7 +452,7 @@ int main(int argc, char **argv) compress_sys_file = exeflat(argv[1], argv[2], argv[3], silentSegments, silentcount, - UPX, &header); + UPX, 1, &header); if (!UPX) exit(0); @@ -445,7 +499,7 @@ int main(int argc, char **argv) { exeflat(tmpexe, argv[2], argv[3], silentSegments, silentcount, - FALSE, &header); + FALSE, 0, &header); remove(tmpexe); }