diff options
Diffstat (limited to 'recovery/recovery_updater.cpp')
| -rw-r--r-- | recovery/recovery_updater.cpp | 184 |
1 files changed, 184 insertions, 0 deletions
diff --git a/recovery/recovery_updater.cpp b/recovery/recovery_updater.cpp new file mode 100644 index 0000000..0b0200f --- /dev/null +++ b/recovery/recovery_updater.cpp @@ -0,0 +1,184 @@ +/* + * 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/platform/7824900.sdhci/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, "%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, "%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_cm() { + RegisterFunction("cm.verify_trustzone", VerifyTrustZoneFn); +} |