1 /*
2  * Copyright (C) 2008 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 #pragma once
18 
19 #include <stdint.h>
20 
21 #include <functional>
22 #include <memory>
23 #include <vector>
24 
25 #include <openssl/ec_key.h>
26 #include <openssl/rsa.h>
27 #include <openssl/sha.h>
28 
29 constexpr size_t MiB = 1024 * 1024;
30 
31 using HasherUpdateCallback = std::function<void(const uint8_t* addr, uint64_t size)>;
32 
33 struct RSADeleter {
operatorRSADeleter34   void operator()(RSA* rsa) const {
35     RSA_free(rsa);
36   }
37 };
38 
39 struct ECKEYDeleter {
operatorECKEYDeleter40   void operator()(EC_KEY* ec_key) const {
41     EC_KEY_free(ec_key);
42   }
43 };
44 
45 struct Certificate {
46   typedef enum {
47     KEY_TYPE_RSA,
48     KEY_TYPE_EC,
49   } KeyType;
50 
CertificateCertificate51   Certificate(int hash_len_, KeyType key_type_, std::unique_ptr<RSA, RSADeleter>&& rsa_,
52               std::unique_ptr<EC_KEY, ECKEYDeleter>&& ec_)
53       : hash_len(hash_len_), key_type(key_type_), rsa(std::move(rsa_)), ec(std::move(ec_)) {}
54 
55   // SHA_DIGEST_LENGTH (SHA-1) or SHA256_DIGEST_LENGTH (SHA-256)
56   int hash_len;
57   KeyType key_type;
58   std::unique_ptr<RSA, RSADeleter> rsa;
59   std::unique_ptr<EC_KEY, ECKEYDeleter> ec;
60 };
61 
62 class VerifierInterface {
63  public:
64   virtual ~VerifierInterface() = default;
65 
66   // Returns the package size in bytes.
67   virtual uint64_t GetPackageSize() const = 0;
68 
69   // Reads |byte_count| data starting from |offset|, and puts the result in |buffer|.
70   virtual bool ReadFullyAtOffset(uint8_t* buffer, uint64_t byte_count, uint64_t offset) = 0;
71 
72   // Updates the hash contexts for |length| bytes data starting from |start|.
73   virtual bool UpdateHashAtOffset(const std::vector<HasherUpdateCallback>& hashers, uint64_t start,
74                                   uint64_t length) = 0;
75 
76   // Updates the progress in fraction during package verification.
77   virtual void SetProgress(float progress) = 0;
78 };
79 
80 //  Looks for an RSA signature embedded in the .ZIP file comment given the path to the zip.
81 //  Verifies that it matches one of the given public keys. Returns VERIFY_SUCCESS or
82 //  VERIFY_FAILURE (if any error is encountered or no key matches the signature).
83 int verify_file(VerifierInterface* package, const std::vector<Certificate>& keys);
84 
85 // Checks that the RSA key has a modulus of 2048 or 4096 bits long, and public exponent is 3 or
86 // 65537.
87 bool CheckRSAKey(const std::unique_ptr<RSA, RSADeleter>& rsa);
88 
89 // Checks that the field size of the curve for the EC key is 256 bits.
90 bool CheckECKey(const std::unique_ptr<EC_KEY, ECKEYDeleter>& ec_key);
91 
92 // Parses a PEM-encoded x509 certificate from the given buffer and saves it into |cert|. Returns
93 // false if there is a parsing failure or the signature's encryption algorithm is not supported.
94 bool LoadCertificateFromBuffer(const std::vector<uint8_t>& pem_content, Certificate* cert);
95 
96 // Iterates over the zip entries with the suffix "x509.pem" and returns a list of recognized
97 // certificates. Returns an empty list if we fail to parse any of the entries.
98 std::vector<Certificate> LoadKeysFromZipfile(const std::string& zip_name);
99 
100 #define VERIFY_SUCCESS 0
101 #define VERIFY_FAILURE 1
102