diff options
Diffstat (limited to 'src/lib/x509/x509_obj.cpp')
| -rw-r--r-- | src/lib/x509/x509_obj.cpp | 93 |
1 files changed, 87 insertions, 6 deletions
diff --git a/src/lib/x509/x509_obj.cpp b/src/lib/x509/x509_obj.cpp index 3f2aa5518..f566be00e 100644 --- a/src/lib/x509/x509_obj.cpp +++ b/src/lib/x509/x509_obj.cpp @@ -16,6 +16,36 @@ namespace Botan { +namespace { +struct Pss_params + { + AlgorithmIdentifier hash_algo; + AlgorithmIdentifier mask_gen_algo; + AlgorithmIdentifier mask_gen_hash; // redundant: decoded mask_gen_algo.parameters + size_t salt_len; + size_t trailer_field; + }; + +Pss_params decode_pss_params(const std::vector<uint8_t>& encoded_pss_params) + { + Pss_params pss_parameter; + BER_Decoder(encoded_pss_params) + .start_cons(SEQUENCE) + .decode_optional(pss_parameter.hash_algo, ASN1_Tag(0), PRIVATE, AlgorithmIdentifier("SHA-160", + AlgorithmIdentifier::USE_NULL_PARAM)) + .decode_optional(pss_parameter.mask_gen_algo, ASN1_Tag(1), PRIVATE, + AlgorithmIdentifier("MGF1", DER_Encoder().encode(AlgorithmIdentifier("SHA-160", + AlgorithmIdentifier::USE_NULL_PARAM)).get_contents_unlocked())) + .decode_optional(pss_parameter.salt_len, ASN1_Tag(2), PRIVATE, size_t(20)) + .decode_optional(pss_parameter.trailer_field, ASN1_Tag(3), PRIVATE, size_t(1)) + .end_cons(); + + BER_Decoder(pss_parameter.mask_gen_algo.parameters).decode(pss_parameter.mask_gen_hash); + + return pss_parameter; + } +} + /* * Create a generic X.509 object */ @@ -145,13 +175,22 @@ std::string X509_Object::hash_used_for_signature() const throw Internal_Error("Invalid name format found for " + oid.as_string()); - std::vector<std::string> pad_and_hash = - parse_algorithm_name(sig_info[1]); + if(sig_info[1] == "EMSA4") + { + return OIDS::lookup(decode_pss_params(signature_algorithm().parameters).hash_algo.oid); + } + else + { + std::vector<std::string> pad_and_hash = + parse_algorithm_name(sig_info[1]); - if(pad_and_hash.size() != 2) - throw Internal_Error("Invalid name format " + sig_info[1]); + if(pad_and_hash.size() != 2) + { + throw Internal_Error("Invalid name format " + sig_info[1]); + } - return pad_and_hash[1]; + return pad_and_hash[1]; + } } /* @@ -163,7 +202,7 @@ bool X509_Object::check_signature(const Public_Key* pub_key) const throw Exception("No key provided for " + m_PEM_label_pref + " signature check"); std::unique_ptr<const Public_Key> key(pub_key); return check_signature(*key); -} + } /* * Check the signature on an object @@ -181,6 +220,48 @@ bool X509_Object::check_signature(const Public_Key& pub_key) const Signature_Format format = (pub_key.message_parts() >= 2) ? DER_SEQUENCE : IEEE_1363; + if(padding == "EMSA4") + { + // "MUST contain RSASSA-PSS-params" + if(signature_algorithm().parameters.empty()) + { + return false; + } + + Pss_params pss_parameter = decode_pss_params(signature_algorithm().parameters); + + // hash_algo must be SHA1, SHA2-224, SHA2-256, SHA2-384 or SHA2-512 + std::string hash_algo = OIDS::lookup(pss_parameter.hash_algo.oid); + if(hash_algo != "SHA-160" && hash_algo != "SHA-224" && hash_algo != "SHA-256" && hash_algo != "SHA-384" + && hash_algo != "SHA-512") + { + return false; + } + + std::string mgf_algo = OIDS::lookup(pss_parameter.mask_gen_algo.oid); + if(mgf_algo != "MGF1") + { + return false; + } + + // For MGF1, it is strongly RECOMMENDED that the underlying hash function be the same as the one identified by hashAlgorithm + // Must be SHA1, SHA2-224, SHA2-256, SHA2-384 or SHA2-512 + if(pss_parameter.mask_gen_hash.oid != pss_parameter.hash_algo.oid) + { + return false; + } + + if(pss_parameter.trailer_field != 1) + { + return false; + } + + padding += "(" + hash_algo; + padding += "," + mgf_algo; + padding += "," + std::to_string(pss_parameter.salt_len) + + ")"; // salt_len is actually not used for verification. Length is inferred from the signature + } + PK_Verifier verifier(pub_key, padding, format); return verifier.verify_message(tbs_data(), signature()); |