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-rw-r--r--verifier.cpp107
1 files changed, 53 insertions, 54 deletions
diff --git a/verifier.cpp b/verifier.cpp
index 3beaa6e02..fa344d746 100644
--- a/verifier.cpp
+++ b/verifier.cpp
@@ -24,6 +24,7 @@
#include <algorithm>
#include <functional>
#include <memory>
+#include <vector>
#include <android-base/logging.h>
#include <openssl/bn.h>
@@ -60,51 +61,53 @@ 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* ctx = asn1_context_new(pkcs7_der, pkcs7_der_len);
+ if (ctx == NULL) {
+ return false;
+ }
- 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_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)) {
+ const uint8_t* sig_der_ptr;
+ size_t sig_der_length;
+ if (asn1_octet_string_get(sig_seq, &sig_der_ptr, &sig_der_length)) {
+ sig_der->resize(sig_der_length);
+ std::copy(sig_der_ptr, sig_der_ptr + sig_der_length, sig_der->begin());
}
- asn1_context_free(signed_data_app);
+ asn1_context_free(sig_seq);
+ }
+ asn1_context_free(sig_set);
}
- asn1_context_free(pkcs7_seq);
+ asn1_context_free(signed_data_seq);
+ }
+ asn1_context_free(signed_data_app);
}
- asn1_context_free(ctx);
+ asn1_context_free(pkcs7_seq);
+ }
+ asn1_context_free(ctx);
- return *sig_der != NULL;
+ return !sig_der->empty();
}
/*
@@ -115,7 +118,7 @@ static bool read_pkcs7(uint8_t* pkcs7_der, size_t pkcs7_der_len, uint8_t** sig_d
* Returns VERIFY_SUCCESS or VERIFY_FAILURE (if any error is encountered or no key matches the
* signature).
*/
-int verify_file(unsigned char* addr, size_t length, const std::vector<Certificate>& keys,
+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);
@@ -136,7 +139,7 @@ int verify_file(unsigned char* addr, size_t length, const std::vector<Certificat
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) {
LOG(ERROR) << "footer is wrong";
@@ -168,7 +171,7 @@ int verify_file(unsigned char* addr, size_t length, const std::vector<Certificat
// (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) {
@@ -177,7 +180,7 @@ int verify_file(unsigned char* addr, size_t length, const std::vector<Certificat
}
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 (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.
@@ -226,16 +229,14 @@ int verify_file(unsigned char* addr, size_t length, const std::vector<Certificat
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;
+ const uint8_t* signature = eocd + eocd_size - signature_start;
size_t signature_size = signature_start - FOOTER_SIZE;
LOG(INFO) << "signature (offset: " << std::hex << (length - signature_start) << ", length: "
<< signature_size << "): " << print_hex(signature, signature_size);
- if (!read_pkcs7(signature, signature_size, &sig_der, &sig_der_length)) {
+ 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;
}
@@ -262,22 +263,21 @@ int verify_file(unsigned char* addr, size_t length, const std::vector<Certificat
// 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())) {
+ 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;
- 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())) {
+ 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;
- free(sig_der);
return VERIFY_SUCCESS;
} else {
LOG(INFO) << "Unknown key type " << key.key_type;
@@ -291,7 +291,6 @@ int verify_file(unsigned char* addr, size_t length, const std::vector<Certificat
if (need_sha256) {
LOG(INFO) << "SHA-256 digest: " << print_hex(sha256, SHA256_DIGEST_LENGTH);
}
- free(sig_der);
LOG(ERROR) << "failed to verify whole-file signature";
return VERIFY_FAILURE;
}
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-17 15:11:43 +0100