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#define READ_INCREMENT 4096
#define REG_NONE 0UL /* No value type */
#define REG_SZ 1UL /* Unicode nul terminated string */
#define REG_EXPAND_SZ 2UL /* Unicode nul terminated string */
#define REG_BINARY 3UL /* Free form binary */
#define REG_DWORD 4UL /* 32-bit number */
#define REG_DWORD_LITTLE_ENDIAN 4UL /* 32-bit number (same as REG_DWORD) */
#define REG_DWORD_BIG_ENDIAN 5UL /* 32-bit number */
#define REG_LINK 6UL /* Symbolic Link (unicode) */
#define REG_MULTI_SZ 7UL /* Multiple Unicode strings */
#define REG_RESOURCE_LIST 8UL /* Resource list in the resource map */
#define REG_FULL_RESOURCE_DESCRIPTOR 9UL /* Resource list in the hardware description */
#define REG_RESOURCE_REQUIREMENTS_LIST 10UL
#define REG_QWORD 11UL /* 64-bit number */
#define REG_QWORD_LITTLE_ENDIAN 11UL /* 64-bit number (same as REG_QWORD) */
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <stdint.h>
#include <stdbool.h>
#include <string.h>
static size_t buf_len = 0;
static size_t pol_len = 0;
static size_t pol_index = 0;
static char *buf = NULL;
static void cleanup(void) {
if (buf) {
free(buf);
}
}
static const char *typestr(uint32_t type) {
static char unknown_name[7];
switch (type) {
case REG_NONE: return "REG_NONE";
case REG_SZ: return "REG_SZ";
case REG_EXPAND_SZ: return "REG_EXPAND_SZ";
case REG_BINARY: return "REG_BINARY";
case REG_DWORD: return "REG_DWORD";
case REG_DWORD_BIG_ENDIAN: return "REG_DWORD_BIG_ENDIAN";
case REG_LINK: return "REG_LINK";
case REG_MULTI_SZ: return "REG_MULTI_SZ";
case REG_RESOURCE_LIST: return "REG_RESOURCE_LIST";
case REG_FULL_RESOURCE_DESCRIPTOR: return "REG_FULL_RESOURCE_DESCRIPTOR";
case REG_RESOURCE_REQUIREMENTS_LIST: return "REG_RESOURCE_REQUIREMENTS_LIST";
case REG_QWORD: return "REG_QWORD";
default: {
snprintf(unknown_name, sizeof(unknown_name), "0x%x", type);
return unknown_name;
}
}
}
static char *bufget(size_t len, bool force, size_t *len_out) {
char *buf_pre = buf + pol_index;
if (len_out != NULL) {
*len_out = len;
}
/* pol_index + len = the index to read in the NEXT call
* This call reads buf[pol_index_pre, pol_index_pre + len - 1] */
if ((pol_index += len) >= (pol_len + 1)) {
printf("NPI %u\n", pol_index);
if (force) {
fprintf(stderr, "Invalid registry policy file: Unexpected EOF at %u, require %u more bytes.\n", pol_index - len, len);
exit(1);
} else {
pol_index = pol_len - 1;
if (len_out != NULL) {
*len_out = pol_index - (buf_pre - buf) /* pol_index pre */ + 1;
}
}
}
return buf_pre;
}
static void bufret(size_t len) {
pol_index -= len;
}
static char *bufgetf(size_t len) {
return bufget(len, true, NULL);
}
static char *bufgett(size_t len, size_t *len_out) {
return bufget(len, false, len_out);
}
static char bufgetchr(void) {
char *b = bufgetf(2);
if (b[1] != 0) {
fprintf(stderr, "Illegal char at %u\n", pol_index);
exit(1);
}
return b[0];
}
static void bufprintnstr(uint32_t len) {
for (len - 1; len >= 0; len --) {
char c = bufgetchr();
if (c == 0) {
return;
}
printf("%c", c);
}
}
static void bufprintstr(void) {
bufprintnstr(UINT32_MAX);
}
static void bufasschr(char c) {
const char a = bufgetchr();
if (a != c) {
fprintf(stderr, "Expected a '%c' at %u, but got a '%c'\n", c, pol_index, a);
exit(4);
}
}
static uint32_t bufgetdword(void) {
return (uint32_t) *bufgetf(4);
}
int main(int argc, char **argv) {
atexit(cleanup);
char *path;
if (argc == 2) {
path = argv[1];
} else if (argc == 1) {
path = "Registry.pol";
} else {
fprintf(stderr, "Usage: %s /path/to/Registry.pol\n", argv[0]);
return 64;
}
FILE *pol = fopen(path, "r");
if (!pol) {
fprintf(stderr, "Cannot open %s: %s\n", path, strerror(errno));
return errno;
}
for (; !feof(pol) && !ferror(pol); ) {
void *b = realloc(buf, buf_len += READ_INCREMENT);
if (!b) {
fprintf(stderr, "Cannot allocate memory: %s\n", strerror(errno));
return errno;
}
buf = b;
pol_len += fread((void *)(buf + pol_len), 1, READ_INCREMENT, pol);
}
if (ferror(pol)) {
fprintf(strerror, "Cannot read the file: %s\n", strerror(ferror(pol)));
return ferror(pol);
}
fclose(pol);
pol = NULL;
if (memcmp(bufgetf(4), "PReg", 4) != 0) {
fprintf(stderr, "Not a valid registry policy file.\n");
return 1;
}
const uint32_t ver = bufgetdword();
if (ver != 1) {
fprintf(stderr, "Unsupported format version: %u. Only supported version 1 at this time.\n", ver);
return 1;
}
while (pol_index < pol_len) {
bufasschr('[');
/* key */
bufprintstr();
bufasschr(';');
printf(", Value = ");
/* value */
bufprintstr();
bufasschr(';');
printf(" (");
/* type */
const uint32_t type = bufgetdword();
bufasschr(';');
printf("%s) ", typestr(type));
/* size */
const uint32_t size = bufgetdword();
bufasschr(';');
/* data */
const uint32_t endi = pol_index + size;
switch (type) {
case REG_SZ:
case REG_EXPAND_SZ: {
bufprintnstr(size);
break;
}
case REG_DWORD: {
if (size != 4) {
fprintf(stderr, "Incorrect size of REG_DWORD at %d\n", pol_index);
return 1;
}
printf("%d", bufgetdword());
break;
}
case REG_DWORD_BIG_ENDIAN:
case REG_NONE:
case REG_BINARY:
case REG_LINK:
case REG_MULTI_SZ:
case REG_RESOURCE_LIST:
case REG_FULL_RESOURCE_DESCRIPTOR:
case REG_RESOURCE_REQUIREMENTS_LIST:
case REG_QWORD:
default: {
/* seek */
bufgetf(size);
break;
}
}
bufasschr(']');
printf("\n");
}
}
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