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-rw-r--r--verifier.cpp466
1 files changed, 280 insertions, 186 deletions
diff --git a/verifier.cpp b/verifier.cpp
index bf7071d13..2d1b0e74f 100644
--- a/verifier.cpp
+++ b/verifier.cpp
@@ -14,25 +14,27 @@
* limitations under the License.
*/
-#include "asn1_decoder.h"
-#include "common.h"
-#include "ui.h"
-#include "verifier.h"
-
-#include "mincrypt/dsa_sig.h"
-#include "mincrypt/p256.h"
-#include "mincrypt/p256_ecdsa.h"
-#include "mincrypt/rsa.h"
-#include "mincrypt/sha.h"
-#include "mincrypt/sha256.h"
-
#include <errno.h>
#include <malloc.h>
#include <stdio.h>
#include <string.h>
+#include <algorithm>
+#include <memory>
+
+#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;
+static constexpr size_t MiB = 1024 * 1024;
+
/*
* Simple version of PKCS#7 SignedData extraction. This extracts the
* signature OCTET STRING to be used for signature verification.
@@ -113,7 +115,7 @@ static bool read_pkcs7(uint8_t* pkcs7_der, size_t pkcs7_der_len, uint8_t** sig_d
// or no key matches the signature).
int verify_file(unsigned char* addr, size_t length,
- const Certificate* pKeys, unsigned int numKeys) {
+ const std::vector<Certificate>& keys) {
ui->SetProgress(0.0);
// An archive with a whole-file signature will end in six bytes:
@@ -182,8 +184,7 @@ int verify_file(unsigned char* addr, size_t length,
return VERIFY_FAILURE;
}
- size_t i;
- for (i = 4; i < eocd_size-3; ++i) {
+ 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
@@ -195,30 +196,30 @@ int verify_file(unsigned char* addr, size_t length,
}
}
-#define BUFFER_SIZE 4096
-
bool need_sha1 = false;
bool need_sha256 = false;
- for (i = 0; i < numKeys; ++i) {
- switch (pKeys[i].hash_len) {
- case SHA_DIGEST_SIZE: need_sha1 = true; break;
- case SHA256_DIGEST_SIZE: need_sha256 = true; break;
+ 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;
- SHA_init(&sha1_ctx);
- SHA256_init(&sha256_ctx);
+ SHA1_Init(&sha1_ctx);
+ SHA256_Init(&sha256_ctx);
double frac = -1.0;
size_t so_far = 0;
while (so_far < signed_len) {
- size_t size = signed_len - so_far;
- if (size > BUFFER_SIZE) size = BUFFER_SIZE;
+ // 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) SHA_update(&sha1_ctx, addr + so_far, size);
- if (need_sha256) SHA256_update(&sha256_ctx, addr + so_far, size);
+ 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;
@@ -228,15 +229,22 @@ int verify_file(unsigned char* addr, size_t length,
}
}
- const uint8_t* sha1 = SHA_final(&sha1_ctx);
- const uint8_t* sha256 = SHA256_final(&sha256_ctx);
+ 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 = NULL;
+ 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;
- if (!read_pkcs7(eocd + eocd_size - signature_start, signature_size, &sig_der,
- &sig_der_length)) {
+
+ LOGI("signature (offset: 0x%zx, length: %zu): %s\n",
+ length - signature_start, signature_size,
+ print_hex(signature, signature_size).c_str());
+
+ if (!read_pkcs7(signature, signature_size, &sig_der, &sig_der_length)) {
LOGE("Could not find signature DER block\n");
return VERIFY_FAILURE;
}
@@ -246,25 +254,28 @@ int verify_file(unsigned char* addr, size_t length,
* any key can match, we need to try each before determining a verification
* failure has happened.
*/
- for (i = 0; i < numKeys; ++i) {
+ size_t i = 0;
+ for (const auto& key : keys) {
const uint8_t* hash;
- switch (pKeys[i].hash_len) {
- case SHA_DIGEST_SIZE: hash = sha1; break;
- case SHA256_DIGEST_SIZE: hash = sha256; break;
- default: continue;
+ 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 (pKeys[i].key_type == Certificate::RSA) {
- if (sig_der_length < RSANUMBYTES) {
- // "signature" block isn't big enough to contain an RSA block.
- LOGI("signature is too short for RSA key %zu\n", i);
- continue;
- }
-
- if (!RSA_verify(pKeys[i].rsa, sig_der, RSANUMBYTES,
- hash, pKeys[i].hash_len)) {
+ 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;
}
@@ -272,18 +283,10 @@ int verify_file(unsigned char* addr, size_t length,
LOGI("whole-file signature verified against RSA key %zu\n", i);
free(sig_der);
return VERIFY_SUCCESS;
- } else if (pKeys[i].key_type == Certificate::EC
- && pKeys[i].hash_len == SHA256_DIGEST_SIZE) {
- p256_int r, s;
- if (!dsa_sig_unpack(sig_der, sig_der_length, &r, &s)) {
- LOGI("Not a DSA signature block for EC key %zu\n", i);
- continue;
- }
-
- p256_int p256_hash;
- p256_from_bin(hash, &p256_hash);
- if (!p256_ecdsa_verify(&(pKeys[i].ec->x), &(pKeys[i].ec->y),
- &p256_hash, &r, &s)) {
+ } 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;
}
@@ -292,14 +295,160 @@ int verify_file(unsigned char* addr, size_t length,
free(sig_der);
return VERIFY_SUCCESS;
} else {
- LOGI("Unknown key type %d\n", pKeys[i].key_type);
+ LOGI("Unknown key type %d\n", 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;
}
+std::unique_ptr<RSA, RSADeleter> parse_rsa_key(FILE* file, uint32_t exponent) {
+ // Read key length in words and n0inv. n0inv is a precomputed montgomery
+ // parameter derived from the modulus and can be used to speed up
+ // verification. n0inv is 32 bits wide here, assuming the verification logic
+ // uses 32 bit arithmetic. However, BoringSSL may use a word size of 64 bits
+ // internally, in which case we don't have a valid n0inv. Thus, we just
+ // ignore the montgomery parameters and have BoringSSL recompute them
+ // internally. If/When the speedup from using the montgomery parameters
+ // becomes relevant, we can add more sophisticated code here to obtain a
+ // 64-bit n0inv and initialize the montgomery parameters in the key object.
+ uint32_t key_len_words = 0;
+ uint32_t n0inv = 0;
+ if (fscanf(file, " %i , 0x%x", &key_len_words, &n0inv) != 2) {
+ return nullptr;
+ }
+
+ if (key_len_words > 8192 / 32) {
+ LOGE("key length (%d) too large\n", key_len_words);
+ return nullptr;
+ }
+
+ // Read the modulus.
+ std::unique_ptr<uint32_t[]> modulus(new uint32_t[key_len_words]);
+ if (fscanf(file, " , { %u", &modulus[0]) != 1) {
+ return nullptr;
+ }
+ for (uint32_t i = 1; i < key_len_words; ++i) {
+ if (fscanf(file, " , %u", &modulus[i]) != 1) {
+ return nullptr;
+ }
+ }
+
+ // Cconvert from little-endian array of little-endian words to big-endian
+ // byte array suitable as input for BN_bin2bn.
+ std::reverse((uint8_t*)modulus.get(),
+ (uint8_t*)(modulus.get() + key_len_words));
+
+ // The next sequence of values is the montgomery parameter R^2. Since we
+ // generally don't have a valid |n0inv|, we ignore this (see comment above).
+ uint32_t rr_value;
+ if (fscanf(file, " } , { %u", &rr_value) != 1) {
+ return nullptr;
+ }
+ for (uint32_t i = 1; i < key_len_words; ++i) {
+ if (fscanf(file, " , %u", &rr_value) != 1) {
+ return nullptr;
+ }
+ }
+ if (fscanf(file, " } } ") != 0) {
+ return nullptr;
+ }
+
+ // Initialize the key.
+ std::unique_ptr<RSA, RSADeleter> key(RSA_new());
+ if (!key) {
+ return nullptr;
+ }
+
+ key->n = BN_bin2bn((uint8_t*)modulus.get(),
+ key_len_words * sizeof(uint32_t), NULL);
+ if (!key->n) {
+ return nullptr;
+ }
+
+ key->e = BN_new();
+ if (!key->e || !BN_set_word(key->e, exponent)) {
+ return nullptr;
+ }
+
+ return key;
+}
+
+struct BNDeleter {
+ void operator()(BIGNUM* bn) {
+ BN_free(bn);
+ }
+};
+
+std::unique_ptr<EC_KEY, ECKEYDeleter> parse_ec_key(FILE* file) {
+ uint32_t key_len_bytes = 0;
+ if (fscanf(file, " %i", &key_len_bytes) != 1) {
+ return nullptr;
+ }
+
+ std::unique_ptr<EC_GROUP, void (*)(EC_GROUP*)> group(
+ EC_GROUP_new_by_curve_name(NID_X9_62_prime256v1), EC_GROUP_free);
+ if (!group) {
+ return nullptr;
+ }
+
+ // Verify that |key_len| matches the group order.
+ if (key_len_bytes != BN_num_bytes(EC_GROUP_get0_order(group.get()))) {
+ return nullptr;
+ }
+
+ // Read the public key coordinates. Note that the byte order in the file is
+ // little-endian, so we convert to big-endian here.
+ std::unique_ptr<uint8_t[]> bytes(new uint8_t[key_len_bytes]);
+ std::unique_ptr<BIGNUM, BNDeleter> point[2];
+ for (int i = 0; i < 2; ++i) {
+ unsigned int byte = 0;
+ if (fscanf(file, " , { %u", &byte) != 1) {
+ return nullptr;
+ }
+ bytes[key_len_bytes - 1] = byte;
+
+ for (size_t i = 1; i < key_len_bytes; ++i) {
+ if (fscanf(file, " , %u", &byte) != 1) {
+ return nullptr;
+ }
+ bytes[key_len_bytes - i - 1] = byte;
+ }
+
+ point[i].reset(BN_bin2bn(bytes.get(), key_len_bytes, nullptr));
+ if (!point[i]) {
+ return nullptr;
+ }
+
+ if (fscanf(file, " }") != 0) {
+ return nullptr;
+ }
+ }
+
+ if (fscanf(file, " } ") != 0) {
+ return nullptr;
+ }
+
+ // Create and initialize the key.
+ std::unique_ptr<EC_KEY, ECKEYDeleter> key(EC_KEY_new());
+ if (!key || !EC_KEY_set_group(key.get(), group.get()) ||
+ !EC_KEY_set_public_key_affine_coordinates(key.get(), point[0].get(),
+ point[1].get())) {
+ return nullptr;
+ }
+
+ return key;
+}
+
// Reads a file containing one or more public keys as produced by
// DumpPublicKey: this is an RSAPublicKey struct as it would appear
// as a C source literal, eg:
@@ -329,140 +478,85 @@ int verify_file(unsigned char* addr, size_t length,
// 4: 2048-bit RSA key with e=65537 and SHA-256 hash
// 5: 256-bit EC key using the NIST P-256 curve parameters and SHA-256 hash
//
-// Returns NULL if the file failed to parse, or if it contain zero keys.
-Certificate*
-load_keys(const char* filename, int* numKeys) {
- Certificate* out = NULL;
- *numKeys = 0;
-
- FILE* f = fopen(filename, "r");
- if (f == NULL) {
+// Returns true on success, and appends the found keys (at least one) to certs.
+// Otherwise returns false if the file failed to parse, or if it contains zero
+// keys. The contents in certs would be unspecified on failure.
+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));
- goto exit;
- }
-
- {
- int i;
- bool done = false;
- while (!done) {
- ++*numKeys;
- out = (Certificate*)realloc(out, *numKeys * sizeof(Certificate));
- Certificate* cert = out + (*numKeys - 1);
- memset(cert, '\0', sizeof(Certificate));
-
- char start_char;
- if (fscanf(f, " %c", &start_char) != 1) goto exit;
- if (start_char == '{') {
- // a version 1 key has no version specifier.
- cert->key_type = Certificate::RSA;
- cert->rsa = (RSAPublicKey*)malloc(sizeof(RSAPublicKey));
- cert->rsa->exponent = 3;
- cert->hash_len = SHA_DIGEST_SIZE;
- } else if (start_char == 'v') {
- int version;
- if (fscanf(f, "%d {", &version) != 1) goto exit;
- switch (version) {
- case 2:
- cert->key_type = Certificate::RSA;
- cert->rsa = (RSAPublicKey*)malloc(sizeof(RSAPublicKey));
- cert->rsa->exponent = 65537;
- cert->hash_len = SHA_DIGEST_SIZE;
- break;
- case 3:
- cert->key_type = Certificate::RSA;
- cert->rsa = (RSAPublicKey*)malloc(sizeof(RSAPublicKey));
- cert->rsa->exponent = 3;
- cert->hash_len = SHA256_DIGEST_SIZE;
- break;
- case 4:
- cert->key_type = Certificate::RSA;
- cert->rsa = (RSAPublicKey*)malloc(sizeof(RSAPublicKey));
- cert->rsa->exponent = 65537;
- cert->hash_len = SHA256_DIGEST_SIZE;
- break;
- case 5:
- cert->key_type = Certificate::EC;
- cert->ec = (ECPublicKey*)calloc(1, sizeof(ECPublicKey));
- cert->hash_len = SHA256_DIGEST_SIZE;
- break;
- default:
- goto exit;
- }
- }
+ return false;
+ }
- if (cert->key_type == Certificate::RSA) {
- RSAPublicKey* key = cert->rsa;
- if (fscanf(f, " %i , 0x%x , { %u",
- &(key->len), &(key->n0inv), &(key->n[0])) != 3) {
- goto exit;
- }
- if (key->len != RSANUMWORDS) {
- LOGE("key length (%d) does not match expected size\n", key->len);
- goto exit;
- }
- for (i = 1; i < key->len; ++i) {
- if (fscanf(f, " , %u", &(key->n[i])) != 1) goto exit;
- }
- if (fscanf(f, " } , { %u", &(key->rr[0])) != 1) goto exit;
- for (i = 1; i < key->len; ++i) {
- if (fscanf(f, " , %u", &(key->rr[i])) != 1) goto exit;
- }
- fscanf(f, " } } ");
-
- LOGI("read key e=%d hash=%d\n", key->exponent, cert->hash_len);
- } else if (cert->key_type == Certificate::EC) {
- ECPublicKey* key = cert->ec;
- int key_len;
- unsigned int byte;
- uint8_t x_bytes[P256_NBYTES];
- uint8_t y_bytes[P256_NBYTES];
- if (fscanf(f, " %i , { %u", &key_len, &byte) != 2) goto exit;
- if (key_len != P256_NBYTES) {
- LOGE("Key length (%d) does not match expected size %d\n", key_len, P256_NBYTES);
- goto exit;
- }
- x_bytes[P256_NBYTES - 1] = byte;
- for (i = P256_NBYTES - 2; i >= 0; --i) {
- if (fscanf(f, " , %u", &byte) != 1) goto exit;
- x_bytes[i] = byte;
- }
- if (fscanf(f, " } , { %u", &byte) != 1) goto exit;
- y_bytes[P256_NBYTES - 1] = byte;
- for (i = P256_NBYTES - 2; i >= 0; --i) {
- if (fscanf(f, " , %u", &byte) != 1) goto exit;
- y_bytes[i] = byte;
- }
- fscanf(f, " } } ");
- p256_from_bin(x_bytes, &key->x);
- p256_from_bin(y_bytes, &key->y);
- } else {
- LOGE("Unknown key type %d\n", cert->key_type);
- goto exit;
+ while (true) {
+ certs.emplace_back(0, Certificate::KEY_TYPE_RSA, nullptr, nullptr);
+ Certificate& cert = certs.back();
+ uint32_t exponent = 0;
+
+ char start_char;
+ if (fscanf(f.get(), " %c", &start_char) != 1) return false;
+ if (start_char == '{') {
+ // a version 1 key has no version specifier.
+ cert.key_type = Certificate::KEY_TYPE_RSA;
+ exponent = 3;
+ cert.hash_len = SHA_DIGEST_LENGTH;
+ } else if (start_char == 'v') {
+ int version;
+ if (fscanf(f.get(), "%d {", &version) != 1) return false;
+ switch (version) {
+ case 2:
+ cert.key_type = Certificate::KEY_TYPE_RSA;
+ exponent = 65537;
+ cert.hash_len = SHA_DIGEST_LENGTH;
+ break;
+ case 3:
+ cert.key_type = Certificate::KEY_TYPE_RSA;
+ exponent = 3;
+ cert.hash_len = SHA256_DIGEST_LENGTH;
+ break;
+ case 4:
+ cert.key_type = Certificate::KEY_TYPE_RSA;
+ exponent = 65537;
+ cert.hash_len = SHA256_DIGEST_LENGTH;
+ break;
+ case 5:
+ cert.key_type = Certificate::KEY_TYPE_EC;
+ cert.hash_len = SHA256_DIGEST_LENGTH;
+ break;
+ default:
+ return false;
}
+ }
- // if the line ends in a comma, this file has more keys.
- switch (fgetc(f)) {
- case ',':
- // more keys to come.
- break;
-
- case EOF:
- done = true;
- break;
+ if (cert.key_type == Certificate::KEY_TYPE_RSA) {
+ cert.rsa = parse_rsa_key(f.get(), exponent);
+ if (!cert.rsa) {
+ return false;
+ }
- default:
- LOGE("unexpected character between keys\n");
- goto exit;
+ LOGI("read key e=%d hash=%d\n", exponent, 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);
+ return false;
}
- }
- fclose(f);
- return out;
+ // if the line ends in a comma, this file has more keys.
+ int ch = fgetc(f.get());
+ if (ch == ',') {
+ // more keys to come.
+ continue;
+ } else if (ch == EOF) {
+ break;
+ } else {
+ LOGE("unexpected character between keys\n");
+ return false;
+ }
+ }
-exit:
- if (f) fclose(f);
- free(out);
- *numKeys = 0;
- return NULL;
+ return true;
}
generated by cgit v1.2.3 (git 2.25.1) at 2024-07-02 21:30:25 +0200