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_proto| as a protocol buffer containing the Signatures 35 // message and decrypts each signature data using the |pem_public_key|. 36 // |pem_public_key| should be a PEM format RSA public key data. 37 // Pads the 32 bytes |sha256_hash_data| to 256 or 512 bytes according to the 38 // PKCS#1 v1.5 standard; and returns whether *any* of the decrypted hashes 39 // matches the padded hash data. In case of any error parsing the signatures 40 // or the public key, returns false. 41 static bool VerifySignature(const std::string& signature_proto, 42 const std::string& pem_public_key, 43 const brillo::Blob& sha256_hash_data); 44 45 // Decrypts |sig_data| with the given |pem_public_key| and populates 46 // |out_hash_data| with the decoded raw hash. |pem_public_key| should be a PEM 47 // format RSA public key data. Returns true if successful, false otherwise. 48 static bool GetRawHashFromSignature(const brillo::Blob& sig_data, 49 const std::string& pem_public_key, 50 brillo::Blob* out_hash_data); 51 52 // Pads a SHA256 hash so that it may be encrypted/signed with RSA2048 or 53 // RSA4096 using the PKCS#1 v1.5 scheme. 54 // hash should be a pointer to vector of exactly 256 bits. |rsa_size| must be 55 // one of 256 or 512 bytes. The vector will be modified in place and will 56 // result in having a length of 2048 or 4096 bits, depending on the rsa size. 57 // Returns true on success, false otherwise. 58 static bool PadRSASHA256Hash(brillo::Blob* hash, size_t rsa_size); 59 60 private: 61 // This should never be constructed 62 DISALLOW_IMPLICIT_CONSTRUCTORS(PayloadVerifier); 63 }; 64 65 } // namespace chromeos_update_engine 66 67 #endif // UPDATE_ENGINE_PAYLOAD_CONSUMER_PAYLOAD_VERIFIER_H_ 68