1 //
2 // Copyright (C) 2014 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 #ifndef UPDATE_ENGINE_PAYLOAD_CONSUMER_PAYLOAD_VERIFIER_H_
18 #define UPDATE_ENGINE_PAYLOAD_CONSUMER_PAYLOAD_VERIFIER_H_
19 
20 #include <string>
21 
22 #include <base/macros.h>
23 #include <brillo/secure_blob.h>
24 
25 #include "update_engine/update_metadata.pb.h"
26 
27 // This class encapsulates methods used for payload signature verification.
28 // See payload_generator/payload_signer.h for payload signing.
29 
30 namespace chromeos_update_engine {
31 
32 class PayloadVerifier {
33  public:
34   // Interprets |signature_blob| as a protocol buffer containing the Signatures
35   // message and decrypts each signature data using the |public_key_path|.
36   // Returns whether *any* of the decrypted hashes matches the |hash_data|.
37   // In case of any error parsing the signatures or the public key, returns
38   // false.
39   static bool VerifySignature(const brillo::Blob& signature_blob,
40                               const std::string& public_key_path,
41                               const brillo::Blob& hash_data);
42 
43   // Decrypts sig_data with the given public_key_path and populates
44   // out_hash_data with the decoded raw hash. Returns true if successful,
45   // false otherwise.
46   static bool GetRawHashFromSignature(const brillo::Blob& sig_data,
47                                       const std::string& public_key_path,
48                                       brillo::Blob* out_hash_data);
49 
50   // Pads a SHA256 hash so that it may be encrypted/signed with RSA2048
51   // using the PKCS#1 v1.5 scheme.
52   // hash should be a pointer to vector of exactly 256 bits. The vector
53   // will be modified in place and will result in having a length of
54   // 2048 bits. Returns true on success, false otherwise.
55   static bool PadRSA2048SHA256Hash(brillo::Blob* hash);
56 
57  private:
58   // This should never be constructed
59   DISALLOW_IMPLICIT_CONSTRUCTORS(PayloadVerifier);
60 };
61 
62 }  // namespace chromeos_update_engine
63 
64 #endif  // UPDATE_ENGINE_PAYLOAD_CONSUMER_PAYLOAD_VERIFIER_H_
65