diff options
Diffstat (limited to 'verifier.cpp')
| -rw-r--r-- | verifier.cpp | 456 |
1 files changed, 220 insertions, 236 deletions
diff --git a/verifier.cpp b/verifier.cpp index 229cc9dfe..2ef9c4c37 100644 --- a/verifier.cpp +++ b/verifier.cpp @@ -14,26 +14,25 @@ * limitations under the License. */ +#include "verifier.h" + #include <errno.h> -#include <malloc.h> #include <stdio.h> +#include <stdlib.h> #include <string.h> #include <algorithm> +#include <functional> #include <memory> +#include <vector> +#include <android-base/logging.h> +#include <openssl/bn.h> #include <openssl/ecdsa.h> #include <openssl/obj_mac.h> #include "asn1_decoder.h" -#include "common.h" #include "print_sha1.h" -#include "ui.h" -#include "verifier.h" - -//extern RecoveryUI* ui; - -#define PUBLIC_KEYS_FILE "/res/keys" static constexpr size_t MiB = 1024 * 1024; @@ -62,261 +61,246 @@ static constexpr size_t MiB = 1024 * 1024; * SEQUENCE (SignatureAlgorithmIdentifier) * OCTET STRING (SignatureValue) */ -static bool read_pkcs7(uint8_t* pkcs7_der, size_t pkcs7_der_len, uint8_t** sig_der, - size_t* sig_der_length) { - asn1_context_t* ctx = asn1_context_new(pkcs7_der, pkcs7_der_len); - if (ctx == NULL) { - return false; - } +static bool read_pkcs7(const uint8_t* pkcs7_der, size_t pkcs7_der_len, + std::vector<uint8_t>* sig_der) { + CHECK(sig_der != nullptr); + sig_der->clear(); - asn1_context_t* pkcs7_seq = asn1_sequence_get(ctx); - if (pkcs7_seq != NULL && asn1_sequence_next(pkcs7_seq)) { - asn1_context_t *signed_data_app = asn1_constructed_get(pkcs7_seq); - if (signed_data_app != NULL) { - asn1_context_t* signed_data_seq = asn1_sequence_get(signed_data_app); - if (signed_data_seq != NULL - && asn1_sequence_next(signed_data_seq) - && asn1_sequence_next(signed_data_seq) - && asn1_sequence_next(signed_data_seq) - && asn1_constructed_skip_all(signed_data_seq)) { - asn1_context_t *sig_set = asn1_set_get(signed_data_seq); - if (sig_set != NULL) { - asn1_context_t* sig_seq = asn1_sequence_get(sig_set); - if (sig_seq != NULL - && asn1_sequence_next(sig_seq) - && asn1_sequence_next(sig_seq) - && asn1_sequence_next(sig_seq) - && asn1_sequence_next(sig_seq)) { - uint8_t* sig_der_ptr; - if (asn1_octet_string_get(sig_seq, &sig_der_ptr, sig_der_length)) { - *sig_der = (uint8_t*) malloc(*sig_der_length); - if (*sig_der != NULL) { - memcpy(*sig_der, sig_der_ptr, *sig_der_length); - } - } - asn1_context_free(sig_seq); - } - asn1_context_free(sig_set); - } - asn1_context_free(signed_data_seq); - } - asn1_context_free(signed_data_app); - } - asn1_context_free(pkcs7_seq); - } - asn1_context_free(ctx); + asn1_context ctx(pkcs7_der, pkcs7_der_len); - return *sig_der != NULL; -} + std::unique_ptr<asn1_context> pkcs7_seq(ctx.asn1_sequence_get()); + if (pkcs7_seq == nullptr || !pkcs7_seq->asn1_sequence_next()) { + return false; + } -// 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). + std::unique_ptr<asn1_context> signed_data_app(pkcs7_seq->asn1_constructed_get()); + if (signed_data_app == nullptr) { + return false; + } -int verify_file(unsigned char* addr, size_t length) { - //ui->SetProgress(0.0); + std::unique_ptr<asn1_context> signed_data_seq(signed_data_app->asn1_sequence_get()); + if (signed_data_seq == nullptr || + !signed_data_seq->asn1_sequence_next() || + !signed_data_seq->asn1_sequence_next() || + !signed_data_seq->asn1_sequence_next() || + !signed_data_seq->asn1_constructed_skip_all()) { + return false; + } - std::vector<Certificate> keys; - if (!load_keys(PUBLIC_KEYS_FILE, keys)) { - LOGE("Failed to load keys\n"); - return INSTALL_CORRUPT; - } - LOGI("%d key(s) loaded from %s\n", keys.size(), PUBLIC_KEYS_FILE); + std::unique_ptr<asn1_context> sig_set(signed_data_seq->asn1_set_get()); + if (sig_set == nullptr) { + return false; + } + + std::unique_ptr<asn1_context> sig_seq(sig_set->asn1_sequence_get()); + if (sig_seq == nullptr || + !sig_seq->asn1_sequence_next() || + !sig_seq->asn1_sequence_next() || + !sig_seq->asn1_sequence_next() || + !sig_seq->asn1_sequence_next()) { + return false; + } + + const uint8_t* sig_der_ptr; + size_t sig_der_length; + if (!sig_seq->asn1_octet_string_get(&sig_der_ptr, &sig_der_length)) { + return false; + } + + sig_der->resize(sig_der_length); + std::copy(sig_der_ptr, sig_der_ptr + sig_der_length, sig_der->begin()); + return true; +} + +/* + * Looks for an RSA signature embedded in the .ZIP file comment given the path to the zip. Verifies + * that it matches one of the given public keys. A callback function can be optionally provided for + * posting the progress. + * + * Returns VERIFY_SUCCESS or VERIFY_FAILURE (if any error is encountered or no key matches the + * signature). + */ +int verify_file(const unsigned char* addr, size_t length, const std::vector<Certificate>& keys, + const std::function<void(float)>& set_progress) { + if (set_progress) { + set_progress(0.0); + } - // 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. + // 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 (length < FOOTER_SIZE) { - LOGE("not big enough to contain footer\n"); - return VERIFY_FAILURE; - } + if (length < FOOTER_SIZE) { + LOG(ERROR) << "not big enough to contain footer"; + return VERIFY_FAILURE; + } - unsigned char* footer = addr + length - FOOTER_SIZE; + const unsigned char* footer = addr + length - FOOTER_SIZE; - if (footer[2] != 0xff || footer[3] != 0xff) { - LOGE("footer is wrong\n"); - return VERIFY_FAILURE; - } + if (footer[2] != 0xff || footer[3] != 0xff) { + LOG(ERROR) << "footer is wrong"; + return VERIFY_FAILURE; + } - size_t comment_size = footer[4] + (footer[5] << 8); - size_t signature_start = footer[0] + (footer[1] << 8); - LOGI("comment is %zu bytes; signature %zu bytes from end\n", - comment_size, signature_start); + size_t comment_size = footer[4] + (footer[5] << 8); + size_t signature_start = footer[0] + (footer[1] << 8); + LOG(INFO) << "comment is " << comment_size << " bytes; signature is " << signature_start + << " bytes from end"; - if (signature_start > comment_size) { - LOGE("signature start: %zu is larger than comment size: %zu\n", signature_start, - comment_size); - return VERIFY_FAILURE; - } + if (signature_start > comment_size) { + LOG(ERROR) << "signature start: " << signature_start << " is larger than comment size: " + << comment_size; + return VERIFY_FAILURE; + } - if (signature_start <= FOOTER_SIZE) { - LOGE("Signature start is in the footer"); - return VERIFY_FAILURE; - } + if (signature_start <= FOOTER_SIZE) { + LOG(ERROR) << "Signature start is in the footer"; + 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; + // The end-of-central-directory record is 22 bytes plus any comment length. + size_t eocd_size = comment_size + EOCD_HEADER_SIZE; - if (length < eocd_size) { - LOGE("not big enough to contain EOCD\n"); - return VERIFY_FAILURE; - } + if (length < eocd_size) { + LOG(ERROR) << "not big enough to contain EOCD"; + 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 = length - eocd_size + EOCD_HEADER_SIZE - 2; + // 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 = length - eocd_size + EOCD_HEADER_SIZE - 2; - unsigned char* eocd = addr + length - eocd_size; + const unsigned char* eocd = addr + length - eocd_size; - // 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"); - 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) { + LOG(ERROR) << "signature length doesn't match EOCD marker"; + return VERIFY_FAILURE; + } - for (size_t 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"); - return VERIFY_FAILURE; - } + for (size_t 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, libziparchive will + // find the later (wrong) one, which could be exploitable. Fail the verification if this + // sequence occurs anywhere after the real one. + LOG(ERROR) << "EOCD marker occurs after start of EOCD"; + return VERIFY_FAILURE; } + } - bool need_sha1 = false; - bool need_sha256 = false; - for (const auto& key : keys) { - switch (key.hash_len) { - case SHA_DIGEST_LENGTH: need_sha1 = true; break; - case SHA256_DIGEST_LENGTH: need_sha256 = true; break; - } + bool need_sha1 = false; + bool need_sha256 = false; + for (const auto& key : keys) { + switch (key.hash_len) { + case SHA_DIGEST_LENGTH: need_sha1 = true; break; + case SHA256_DIGEST_LENGTH: need_sha256 = true; break; } + } - SHA_CTX sha1_ctx; - SHA256_CTX sha256_ctx; - SHA1_Init(&sha1_ctx); - SHA256_Init(&sha256_ctx); - - double frac = -1.0; - size_t so_far = 0; - while (so_far < signed_len) { - // On a Nexus 5X, experiment showed 16MiB beat 1MiB by 6% faster for a - // 1196MiB full OTA and 60% for an 89MiB incremental OTA. - // http://b/28135231. - size_t size = std::min(signed_len - so_far, 16 * MiB); - - if (need_sha1) SHA1_Update(&sha1_ctx, addr + so_far, size); - if (need_sha256) SHA256_Update(&sha256_ctx, addr + so_far, size); - so_far += size; - - double f = so_far / (double)signed_len; - if (f > frac + 0.02 || size == so_far) { - //ui->SetProgress(f); - frac = f; - } + SHA_CTX sha1_ctx; + SHA256_CTX sha256_ctx; + SHA1_Init(&sha1_ctx); + SHA256_Init(&sha256_ctx); + + double frac = -1.0; + size_t so_far = 0; + while (so_far < signed_len) { + // On a Nexus 5X, experiment showed 16MiB beat 1MiB by 6% faster for a + // 1196MiB full OTA and 60% for an 89MiB incremental OTA. + // http://b/28135231. + size_t size = std::min(signed_len - so_far, 16 * MiB); + + if (need_sha1) SHA1_Update(&sha1_ctx, addr + so_far, size); + if (need_sha256) SHA256_Update(&sha256_ctx, addr + so_far, size); + so_far += size; + + if (set_progress) { + double f = so_far / (double)signed_len; + if (f > frac + 0.02 || size == so_far) { + set_progress(f); + frac = f; + } } + } - uint8_t sha1[SHA_DIGEST_LENGTH]; - SHA1_Final(sha1, &sha1_ctx); - uint8_t sha256[SHA256_DIGEST_LENGTH]; - SHA256_Final(sha256, &sha256_ctx); - - uint8_t* sig_der = nullptr; - size_t sig_der_length = 0; - - uint8_t* signature = eocd + eocd_size - signature_start; - size_t signature_size = signature_start - FOOTER_SIZE; - - LOGI("signature (offset: 0x%zx, length: %zu): %s\n", - length - signature_start, signature_size, - print_hex(signature, signature_size).c_str()); + uint8_t sha1[SHA_DIGEST_LENGTH]; + SHA1_Final(sha1, &sha1_ctx); + uint8_t sha256[SHA256_DIGEST_LENGTH]; + SHA256_Final(sha256, &sha256_ctx); - if (!read_pkcs7(signature, signature_size, &sig_der, &sig_der_length)) { - LOGE("Could not find signature DER block\n"); - return VERIFY_FAILURE; - } + const uint8_t* signature = eocd + eocd_size - signature_start; + size_t signature_size = signature_start - FOOTER_SIZE; - /* - * Check to make sure at least one of the keys matches the signature. Since - * any key can match, we need to try each before determining a verification - * failure has happened. - */ - size_t i = 0; - for (const auto& key : keys) { - const uint8_t* hash; - int hash_nid; - switch (key.hash_len) { - case SHA_DIGEST_LENGTH: - hash = sha1; - hash_nid = NID_sha1; - break; - case SHA256_DIGEST_LENGTH: - hash = sha256; - hash_nid = NID_sha256; - break; - default: - continue; - } - - // The 6 bytes is the "(signature_start) $ff $ff (comment_size)" that - // the signing tool appends after the signature itself. - if (key.key_type == Certificate::KEY_TYPE_RSA) { - if (!RSA_verify(hash_nid, hash, key.hash_len, sig_der, - sig_der_length, key.rsa.get())) { - LOGI("failed to verify against RSA key %zu\n", i); - continue; - } + LOG(INFO) << "signature (offset: " << std::hex << (length - signature_start) << ", length: " + << signature_size << "): " << print_hex(signature, signature_size); - LOGI("whole-file signature verified against RSA key %zu\n", i); - free(sig_der); - return VERIFY_SUCCESS; - } else if (key.key_type == Certificate::KEY_TYPE_EC - && key.hash_len == SHA256_DIGEST_LENGTH) { - if (!ECDSA_verify(0, hash, key.hash_len, sig_der, - sig_der_length, key.ec.get())) { - LOGI("failed to verify against EC key %zu\n", i); - continue; - } + std::vector<uint8_t> sig_der; + if (!read_pkcs7(signature, signature_size, &sig_der)) { + LOG(ERROR) << "Could not find signature DER block"; + return VERIFY_FAILURE; + } - LOGI("whole-file signature verified against EC key %zu\n", i); - free(sig_der); - return VERIFY_SUCCESS; - } else { - LOGI("Unknown key type %d\n", key.key_type); - } - i++; - } + // Check to make sure at least one of the keys matches the signature. Since any key can match, + // we need to try each before determining a verification failure has happened. + size_t i = 0; + for (const auto& key : keys) { + const uint8_t* hash; + int hash_nid; + switch (key.hash_len) { + case SHA_DIGEST_LENGTH: + hash = sha1; + hash_nid = NID_sha1; + break; + case SHA256_DIGEST_LENGTH: + hash = sha256; + hash_nid = NID_sha256; + break; + default: + continue; + } + + // The 6 bytes is the "(signature_start) $ff $ff (comment_size)" that the signing tool appends + // after the signature itself. + if (key.key_type == Certificate::KEY_TYPE_RSA) { + if (!RSA_verify(hash_nid, hash, key.hash_len, sig_der.data(), sig_der.size(), + key.rsa.get())) { + LOG(INFO) << "failed to verify against RSA key " << i; + continue; + } + + LOG(INFO) << "whole-file signature verified against RSA key " << i; + return VERIFY_SUCCESS; + } else if (key.key_type == Certificate::KEY_TYPE_EC && key.hash_len == SHA256_DIGEST_LENGTH) { + if (!ECDSA_verify(0, hash, key.hash_len, sig_der.data(), sig_der.size(), key.ec.get())) { + LOG(INFO) << "failed to verify against EC key " << i; + continue; + } + + LOG(INFO) << "whole-file signature verified against EC key " << i; + return VERIFY_SUCCESS; + } else { + LOG(INFO) << "Unknown key type " << key.key_type; + } + i++; + } - if (need_sha1) { - LOGI("SHA-1 digest: %s\n", print_hex(sha1, SHA_DIGEST_LENGTH).c_str()); - } - if (need_sha256) { - LOGI("SHA-256 digest: %s\n", print_hex(sha256, SHA256_DIGEST_LENGTH).c_str()); - } - free(sig_der); - LOGE("failed to verify whole-file signature\n"); - return VERIFY_FAILURE; + if (need_sha1) { + LOG(INFO) << "SHA-1 digest: " << print_hex(sha1, SHA_DIGEST_LENGTH); + } + if (need_sha256) { + LOG(INFO) << "SHA-256 digest: " << print_hex(sha256, SHA256_DIGEST_LENGTH); + } + LOG(ERROR) << "failed to verify whole-file signature"; + return VERIFY_FAILURE; } std::unique_ptr<RSA, RSADeleter> parse_rsa_key(FILE* file, uint32_t exponent) { @@ -336,7 +320,7 @@ std::unique_ptr<RSA, RSADeleter> parse_rsa_key(FILE* file, uint32_t exponent) { } if (key_len_words > 8192 / 32) { - LOGE("key length (%d) too large\n", key_len_words); + LOG(ERROR) << "key length (" << key_len_words << ") too large"; return nullptr; } @@ -392,7 +376,7 @@ std::unique_ptr<RSA, RSADeleter> parse_rsa_key(FILE* file, uint32_t exponent) { } struct BNDeleter { - void operator()(BIGNUM* bn) { + void operator()(BIGNUM* bn) const { BN_free(bn); } }; @@ -492,7 +476,7 @@ std::unique_ptr<EC_KEY, ECKEYDeleter> parse_ec_key(FILE* file) { bool load_keys(const char* filename, std::vector<Certificate>& certs) { std::unique_ptr<FILE, decltype(&fclose)> f(fopen(filename, "r"), fclose); if (!f) { - LOGE("opening %s: %s\n", filename, strerror(errno)); + PLOG(ERROR) << "error opening " << filename; return false; } @@ -542,14 +526,14 @@ bool load_keys(const char* filename, std::vector<Certificate>& certs) { return false; } - LOGI("read key e=%d hash=%d\n", exponent, cert.hash_len); + LOG(INFO) << "read key e=" << exponent << " hash=" << cert.hash_len; } else if (cert.key_type == Certificate::KEY_TYPE_EC) { cert.ec = parse_ec_key(f.get()); if (!cert.ec) { return false; } } else { - LOGE("Unknown key type %d\n", cert.key_type); + LOG(ERROR) << "Unknown key type " << cert.key_type; return false; } @@ -561,7 +545,7 @@ bool load_keys(const char* filename, std::vector<Certificate>& certs) { } else if (ch == EOF) { break; } else { - LOGE("unexpected character between keys\n"); + LOG(ERROR) << "unexpected character between keys"; return false; } } |