diff options
Diffstat (limited to 'verifier.c')
| -rw-r--r-- | verifier.c | 184 |
1 files changed, 0 insertions, 184 deletions
diff --git a/verifier.c b/verifier.c deleted file mode 100644 index 729e085cf..000000000 --- a/verifier.c +++ /dev/null @@ -1,184 +0,0 @@ -/* - * Copyright (C) 2008 The Android Open Source 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 "common.h" -#include "verifier.h" - -#include "mincrypt/rsa.h" -#include "mincrypt/sha.h" - -#include <string.h> -#include <stdio.h> -#include <errno.h> - -// Look for an RSA signature embedded in the .ZIP file comment given -// the path to the zip. Verify it matches one of the given public -// keys. -// -// Return VERIFY_SUCCESS, VERIFY_FAILURE (if any error is encountered -// or no key matches the signature). - -int verify_file(const char* path, const RSAPublicKey *pKeys, unsigned int numKeys) { - ui_set_progress(0.0); - - FILE* f = fopen(path, "rb"); - if (f == NULL) { - LOGE("failed to open %s (%s)\n", path, strerror(errno)); - return VERIFY_FAILURE; - } - - // An archive with a whole-file signature will end in six bytes: - // - // (2-byte signature start) $ff $ff (2-byte comment size) - // - // (As far as the ZIP format is concerned, these are part of the - // archive comment.) We start by reading this footer, this tells - // us how far back from the end we have to start reading to find - // the whole comment. - -#define FOOTER_SIZE 6 - - if (fseek(f, -FOOTER_SIZE, SEEK_END) != 0) { - LOGE("failed to seek in %s (%s)\n", path, strerror(errno)); - fclose(f); - return VERIFY_FAILURE; - } - - unsigned char footer[FOOTER_SIZE]; - if (fread(footer, 1, FOOTER_SIZE, f) != FOOTER_SIZE) { - LOGE("failed to read footer from %s (%s)\n", path, strerror(errno)); - fclose(f); - return VERIFY_FAILURE; - } - - if (footer[2] != 0xff || footer[3] != 0xff) { - fclose(f); - return VERIFY_FAILURE; - } - - int comment_size = footer[4] + (footer[5] << 8); - int signature_start = footer[0] + (footer[1] << 8); - LOGI("comment is %d bytes; signature %d bytes from end\n", - comment_size, signature_start); - - if (signature_start - FOOTER_SIZE < RSANUMBYTES) { - // "signature" block isn't big enough to contain an RSA block. - LOGE("signature is too short\n"); - fclose(f); - return VERIFY_FAILURE; - } - -#define EOCD_HEADER_SIZE 22 - - // The end-of-central-directory record is 22 bytes plus any - // comment length. - size_t eocd_size = comment_size + EOCD_HEADER_SIZE; - - if (fseek(f, -eocd_size, SEEK_END) != 0) { - LOGE("failed to seek in %s (%s)\n", path, strerror(errno)); - fclose(f); - return VERIFY_FAILURE; - } - - // Determine how much of the file is covered by the signature. - // This is everything except the signature data and length, which - // includes all of the EOCD except for the comment length field (2 - // bytes) and the comment data. - size_t signed_len = ftell(f) + EOCD_HEADER_SIZE - 2; - - unsigned char* eocd = malloc(eocd_size); - if (eocd == NULL) { - LOGE("malloc for EOCD record failed\n"); - fclose(f); - return VERIFY_FAILURE; - } - if (fread(eocd, 1, eocd_size, f) != eocd_size) { - LOGE("failed to read eocd from %s (%s)\n", path, strerror(errno)); - fclose(f); - return VERIFY_FAILURE; - } - - // If this is really is the EOCD record, it will begin with the - // magic number $50 $4b $05 $06. - if (eocd[0] != 0x50 || eocd[1] != 0x4b || - eocd[2] != 0x05 || eocd[3] != 0x06) { - LOGE("signature length doesn't match EOCD marker\n"); - fclose(f); - return VERIFY_FAILURE; - } - - int i; - for (i = 4; i < eocd_size-3; ++i) { - if (eocd[i ] == 0x50 && eocd[i+1] == 0x4b && - eocd[i+2] == 0x05 && eocd[i+3] == 0x06) { - // if the sequence $50 $4b $05 $06 appears anywhere after - // the real one, minzip will find the later (wrong) one, - // which could be exploitable. Fail verification if - // this sequence occurs anywhere after the real one. - LOGE("EOCD marker occurs after start of EOCD\n"); - fclose(f); - return VERIFY_FAILURE; - } - } - -#define BUFFER_SIZE 4096 - - SHA_CTX ctx; - SHA_init(&ctx); - unsigned char* buffer = malloc(BUFFER_SIZE); - if (buffer == NULL) { - LOGE("failed to alloc memory for sha1 buffer\n"); - fclose(f); - return VERIFY_FAILURE; - } - - double frac = -1.0; - size_t so_far = 0; - fseek(f, 0, SEEK_SET); - while (so_far < signed_len) { - int size = BUFFER_SIZE; - if (signed_len - so_far < size) size = signed_len - so_far; - if (fread(buffer, 1, size, f) != size) { - LOGE("failed to read data from %s (%s)\n", path, strerror(errno)); - fclose(f); - return VERIFY_FAILURE; - } - SHA_update(&ctx, buffer, size); - so_far += size; - double f = so_far / (double)signed_len; - if (f > frac + 0.02 || size == so_far) { - ui_set_progress(f); - frac = f; - } - } - fclose(f); - free(buffer); - - const uint8_t* sha1 = SHA_final(&ctx); - for (i = 0; i < numKeys; ++i) { - // The 6 bytes is the "(signature_start) $ff $ff (comment_size)" that - // the signing tool appends after the signature itself. - if (RSA_verify(pKeys+i, eocd + eocd_size - 6 - RSANUMBYTES, - RSANUMBYTES, sha1)) { - LOGI("whole-file signature verified against key %d\n", i); - free(eocd); - return VERIFY_SUCCESS; - } - } - free(eocd); - LOGE("failed to verify whole-file signature\n"); - return VERIFY_FAILURE; -} |