| 52,14 → 52,14 |
|---|
| |
| /* sets guard values at a few places in memory for later detection of |
| * overflows via memguard_check() */ |
| static void memguard_set(void) { |
| static void memguard_set(char *cmdlinebuf) { |
| BUFFER[sizeof(BUFFER) - 1] = 0xC7; |
| BUFFER[sizeof(BUFFER) - (CMDLINE_MAXLEN + 3)] = 0xC7; |
| cmdlinebuf[CMDLINE_MAXLEN] = 0xC7; |
| } |
| |
| |
| /* checks for valguards at specific memory locations, returns 0 on success */ |
| static int memguard_check(unsigned short rmodseg) { |
| static int memguard_check(unsigned short rmodseg, char *cmdlinebuf) { |
| /* check RMOD signature (would be overwritten in case of stack overflow */ |
| static char msg[] = "!! MEMORY CORRUPTION ## DETECTED !!"; |
| unsigned short far *rmodsig = MK_FP(rmodseg, 0x100 + 6); |
| 69,14 → 69,14 |
|---|
| printf("rmodseg = %04X ; *rmodsig = %04X\r\n", rmodseg, *rmodsig); |
| return(1); |
| } |
| /* check last BUFFER byte (could be overwritten by cmdline) */ |
| /* check last BUFFER byte */ |
| if (BUFFER[sizeof(BUFFER) - 1] != 0xC7) { |
| msg[22] = '2'; |
| outputnl(msg); |
| return(2); |
| } |
| /* check that cmdline BUFFER's end hasn't been touched by something else */ |
| if (BUFFER[sizeof(BUFFER) - (CMDLINE_MAXLEN + 3)] != 0xC7) { |
| /* check last cmdlinebuf byte */ |
| if (cmdlinebuf[CMDLINE_MAXLEN] != 0xC7) { |
| msg[22] = '3'; |
| outputnl(msg); |
| return(3); |
| 614,6 → 614,7 |
|---|
| static unsigned short far *rmod_envseg; |
| static unsigned short far *lastexitcode; |
| static struct rmod_props far *rmod; |
| static char cmdlinebuf[CMDLINE_MAXLEN + 2]; /* 1 extra byte for 0-terminator and another for memguard */ |
| static char *cmdline; |
| |
| rmod = rmod_find(BUFFER_len); |
| 637,7 → 638,7 |
|---|
| } |
| |
| /* install a few guardvals in memory to detect some cases of overflows */ |
| memguard_set(); |
| memguard_set(cmdlinebuf); |
| |
| rmod_envseg = MK_FP(rmod->rmodseg, RMOD_OFFSET_ENVSEG); |
| lastexitcode = MK_FP(rmod->rmodseg, RMOD_OFFSET_LEXITCODE); |
| 669,11 → 670,10 |
|---|
| redir_revert(); |
| |
| /* memory check */ |
| memguard_check(rmod->rmodseg); |
| memguard_check(rmod->rmodseg, cmdlinebuf); |
| |
| /* preset cmdline to point at the end of my general-purpose buffer (with |
| * one extra byte for the NULL terminator and another for memguard val) */ |
| cmdline = BUFFER + sizeof(BUFFER) - (CMDLINE_MAXLEN + 2); |
| /* preset cmdline to point at the dedicated buffer */ |
| cmdline = cmdlinebuf; |
| |
| /* (re)load translation strings if needed */ |
| nls_langreload(BUFFER, *rmod_envseg); |
| 733,7 → 733,7 |
|---|
| } |
| |
| /* try matching (and executing) an internal command */ |
| if (cmd_process(rmod, *rmod_envseg, cmdline, BUFFER) >= -1) { |
| if (cmd_process(rmod, *rmod_envseg, cmdline, BUFFER, sizeof(BUFFER)) >= -1) { |
| /* internal command executed */ |
| redir_revert(); /* revert stdout (in case it was redirected) */ |
| continue; |