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/*
* Copyright (C) 2015, The CyanogenMod Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <sys/mman.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <errno.h>
#include <fcntl.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "edify/expr.h"
#include "updater/install.h"
#define MAX(a, b) (((a) > (b)) ? (a) : (b))
#define ALPHABET_LEN 256
#define KB 1024
#define TZ_PART_PATH "/dev/block/bootdevice/by-name/tz"
#define TZ_VER_STR "QC_IMAGE_VERSION_STRING="
#define TZ_VER_STR_LEN 24
#define TZ_VER_BUF_LEN 255
#define TZ_SZ 500 * KB /* MMAP 500K of TZ, TZ partition is 500K */
/* Boyer-Moore string search implementation from Wikipedia */
/* Return longest suffix length of suffix ending at str[p] */
static int max_suffix_len(const char *str, size_t str_len, size_t p) {
uint32_t i;
for (i = 0; (str[p - i] == str[str_len - 1 - i]) && (i < p); ) {
i++;
}
return i;
}
/* Generate table of distance between last character of pat and rightmost
* occurrence of character c in pat
*/
static void bm_make_delta1(int *delta1, const char *pat, size_t pat_len) {
uint32_t i;
for (i = 0; i < ALPHABET_LEN; i++) {
delta1[i] = pat_len;
}
for (i = 0; i < pat_len - 1; i++) {
uint8_t idx = (uint8_t) pat[i];
delta1[idx] = pat_len - 1 - i;
}
}
/* Generate table of next possible full match from mismatch at pat[p] */
static void bm_make_delta2(int *delta2, const char *pat, size_t pat_len) {
int p;
uint32_t last_prefix = pat_len - 1;
for (p = pat_len - 1; p >= 0; p--) {
/* Compare whether pat[p-pat_len] is suffix of pat */
if (strncmp(pat + p, pat, pat_len - p) == 0) {
last_prefix = p + 1;
}
delta2[p] = last_prefix + (pat_len - 1 - p);
}
for (p = 0; p < (int) pat_len - 1; p++) {
/* Get longest suffix of pattern ending on character pat[p] */
int suf_len = max_suffix_len(pat, pat_len, p);
if (pat[p - suf_len] != pat[pat_len - 1 - suf_len]) {
delta2[pat_len - 1 - suf_len] = pat_len - 1 - p + suf_len;
}
}
}
static char * bm_search(const char *str, size_t str_len, const char *pat,
size_t pat_len) {
int delta1[ALPHABET_LEN];
int delta2[pat_len];
int i;
bm_make_delta1(delta1, pat, pat_len);
bm_make_delta2(delta2, pat, pat_len);
if (pat_len == 0) {
return (char *) str;
}
i = pat_len - 1;
while (i < (int) str_len) {
int j = pat_len - 1;
while (j >= 0 && (str[i] == pat[j])) {
i--;
j--;
}
if (j < 0) {
return (char *) (str + i + 1);
}
i += MAX(delta1[(uint8_t) str[i]], delta2[j]);
}
return NULL;
}
static int get_tz_version(char *ver_str, size_t len) {
int ret = 0;
int fd;
char *tz_data = NULL;
char *offset = NULL;
fd = open(TZ_PART_PATH, O_RDONLY);
if (fd < 0) {
ret = errno;
goto err_ret;
}
tz_data = (char *) mmap(NULL, TZ_SZ, PROT_READ, MAP_PRIVATE, fd, 0);
if (tz_data == (char *)-1) {
ret = errno;
goto err_fd_close;
}
/* Do Boyer-Moore search across TZ data */
offset = bm_search(tz_data, TZ_SZ, TZ_VER_STR, TZ_VER_STR_LEN);
if (offset != NULL) {
strncpy(ver_str, offset + TZ_VER_STR_LEN, len);
} else {
ret = -ENOENT;
}
munmap(tz_data, TZ_SZ);
err_fd_close:
close(fd);
err_ret:
return ret;
}
/* verify_trustzone("TZ_VERSION", "TZ_VERSION", ...) */
Value * VerifyTrustZoneFn(const char *name, State *state, int argc, Expr *argv[]) {
char current_tz_version[TZ_VER_BUF_LEN];
char *tz_version;
int i, ret;
ret = get_tz_version(current_tz_version, TZ_VER_BUF_LEN);
if (ret) {
return ErrorAbort(state, kVendorFailure, "%s() failed to read current TZ version: %d",
name, ret);
}
for (i = 1; i <= argc; i++) {
ret = ReadArgs(state, argv, i, &tz_version);
if (ret < 0) {
return ErrorAbort(state, kArgsParsingFailure, "%s() error parsing arguments: %d",
name, ret);
}
uiPrintf(state, "Comparing TZ version %s to %s",
tz_version, current_tz_version);
if (strncmp(tz_version, current_tz_version, strlen(tz_version)) == 0) {
return StringValue(strdup("1"));
}
}
return StringValue(strdup("0"));
}
void Register_librecovery_updater_asus() {
RegisterFunction("asus.verify_trustzone", VerifyTrustZoneFn);
}
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