diff options
author | lloyd <[email protected]> | 2014-01-10 03:41:59 +0000 |
---|---|---|
committer | lloyd <[email protected]> | 2014-01-10 03:41:59 +0000 |
commit | 6894dca64c04936d07048c0e8cbf7e25858548c3 (patch) | |
tree | 5d572bfde9fe667dab14e3f04b5285a85d8acd95 /src/lib/asn1/der_enc.cpp | |
parent | 9efa3be92442afb3d0b69890a36c7f122df18eda (diff) |
Move lib into src
Diffstat (limited to 'src/lib/asn1/der_enc.cpp')
-rw-r--r-- | src/lib/asn1/der_enc.cpp | 410 |
1 files changed, 410 insertions, 0 deletions
diff --git a/src/lib/asn1/der_enc.cpp b/src/lib/asn1/der_enc.cpp new file mode 100644 index 000000000..c1e5fd45c --- /dev/null +++ b/src/lib/asn1/der_enc.cpp @@ -0,0 +1,410 @@ +/* +* DER Encoder +* (C) 1999-2007 Jack Lloyd +* +* Distributed under the terms of the Botan license +*/ + +#include <botan/der_enc.h> +#include <botan/asn1_obj.h> +#include <botan/bigint.h> +#include <botan/get_byte.h> +#include <botan/parsing.h> +#include <botan/internal/bit_ops.h> +#include <algorithm> + +namespace Botan { + +namespace { + +/* +* DER encode an ASN.1 type tag +*/ +secure_vector<byte> encode_tag(ASN1_Tag type_tag, ASN1_Tag class_tag) + { + if((class_tag | 0xE0) != 0xE0) + throw Encoding_Error("DER_Encoder: Invalid class tag " + + std::to_string(class_tag)); + + secure_vector<byte> encoded_tag; + if(type_tag <= 30) + encoded_tag.push_back(static_cast<byte>(type_tag | class_tag)); + else + { + size_t blocks = high_bit(type_tag) + 6; + blocks = (blocks - (blocks % 7)) / 7; + + encoded_tag.push_back(class_tag | 0x1F); + for(size_t i = 0; i != blocks - 1; ++i) + encoded_tag.push_back(0x80 | ((type_tag >> 7*(blocks-i-1)) & 0x7F)); + encoded_tag.push_back(type_tag & 0x7F); + } + + return encoded_tag; + } + +/* +* DER encode an ASN.1 length field +*/ +secure_vector<byte> encode_length(size_t length) + { + secure_vector<byte> encoded_length; + if(length <= 127) + encoded_length.push_back(static_cast<byte>(length)); + else + { + const size_t top_byte = significant_bytes(length); + + encoded_length.push_back(static_cast<byte>(0x80 | top_byte)); + + for(size_t i = sizeof(length) - top_byte; i != sizeof(length); ++i) + encoded_length.push_back(get_byte(i, length)); + } + return encoded_length; + } + +} + +/* +* Return the encoded SEQUENCE/SET +*/ +secure_vector<byte> DER_Encoder::DER_Sequence::get_contents() + { + const ASN1_Tag real_class_tag = ASN1_Tag(class_tag | CONSTRUCTED); + + if(type_tag == SET) + { + std::sort(set_contents.begin(), set_contents.end()); + for(size_t i = 0; i != set_contents.size(); ++i) + contents += set_contents[i]; + set_contents.clear(); + } + + secure_vector<byte> result; + result += encode_tag(type_tag, real_class_tag); + result += encode_length(contents.size()); + result += contents; + contents.clear(); + + return result; + } + +/* +* Add an encoded value to the SEQUENCE/SET +*/ +void DER_Encoder::DER_Sequence::add_bytes(const byte data[], size_t length) + { + if(type_tag == SET) + set_contents.push_back(secure_vector<byte>(data, data + length)); + else + contents += std::make_pair(data, length); + } + +/* +* Return the type and class taggings +*/ +ASN1_Tag DER_Encoder::DER_Sequence::tag_of() const + { + return ASN1_Tag(type_tag | class_tag); + } + +/* +* DER_Sequence Constructor +*/ +DER_Encoder::DER_Sequence::DER_Sequence(ASN1_Tag t1, ASN1_Tag t2) : + type_tag(t1), class_tag(t2) + { + } + +/* +* Return the encoded contents +*/ +secure_vector<byte> DER_Encoder::get_contents() + { + if(subsequences.size() != 0) + throw Invalid_State("DER_Encoder: Sequence hasn't been marked done"); + + secure_vector<byte> output; + std::swap(output, contents); + return output; + } + +/* +* Start a new ASN.1 SEQUENCE/SET/EXPLICIT +*/ +DER_Encoder& DER_Encoder::start_cons(ASN1_Tag type_tag, + ASN1_Tag class_tag) + { + subsequences.push_back(DER_Sequence(type_tag, class_tag)); + return (*this); + } + +/* +* Finish the current ASN.1 SEQUENCE/SET/EXPLICIT +*/ +DER_Encoder& DER_Encoder::end_cons() + { + if(subsequences.empty()) + throw Invalid_State("DER_Encoder::end_cons: No such sequence"); + + secure_vector<byte> seq = subsequences[subsequences.size()-1].get_contents(); + subsequences.pop_back(); + raw_bytes(seq); + return (*this); + } + +/* +* Start a new ASN.1 EXPLICIT encoding +*/ +DER_Encoder& DER_Encoder::start_explicit(u16bit type_no) + { + ASN1_Tag type_tag = static_cast<ASN1_Tag>(type_no); + + if(type_tag == SET) + throw Internal_Error("DER_Encoder.start_explicit(SET); cannot perform"); + + return start_cons(type_tag, CONTEXT_SPECIFIC); + } + +/* +* Finish the current ASN.1 EXPLICIT encoding +*/ +DER_Encoder& DER_Encoder::end_explicit() + { + return end_cons(); + } + +/* +* Write raw bytes into the stream +*/ +DER_Encoder& DER_Encoder::raw_bytes(const secure_vector<byte>& val) + { + return raw_bytes(&val[0], val.size()); + } + +DER_Encoder& DER_Encoder::raw_bytes(const std::vector<byte>& val) + { + return raw_bytes(&val[0], val.size()); + } + +/* +* Write raw bytes into the stream +*/ +DER_Encoder& DER_Encoder::raw_bytes(const byte bytes[], size_t length) + { + if(subsequences.size()) + subsequences[subsequences.size()-1].add_bytes(bytes, length); + else + contents += std::make_pair(bytes, length); + + return (*this); + } + +/* +* Encode a NULL object +*/ +DER_Encoder& DER_Encoder::encode_null() + { + return add_object(NULL_TAG, UNIVERSAL, nullptr, 0); + } + +/* +* DER encode a BOOLEAN +*/ +DER_Encoder& DER_Encoder::encode(bool is_true) + { + return encode(is_true, BOOLEAN, UNIVERSAL); + } + +/* +* DER encode a small INTEGER +*/ +DER_Encoder& DER_Encoder::encode(size_t n) + { + return encode(BigInt(n), INTEGER, UNIVERSAL); + } + +/* +* DER encode a small INTEGER +*/ +DER_Encoder& DER_Encoder::encode(const BigInt& n) + { + return encode(n, INTEGER, UNIVERSAL); + } + +/* +* DER encode an OCTET STRING or BIT STRING +*/ +DER_Encoder& DER_Encoder::encode(const secure_vector<byte>& bytes, + ASN1_Tag real_type) + { + return encode(&bytes[0], bytes.size(), + real_type, real_type, UNIVERSAL); + } + +/* +* DER encode an OCTET STRING or BIT STRING +*/ +DER_Encoder& DER_Encoder::encode(const std::vector<byte>& bytes, + ASN1_Tag real_type) + { + return encode(&bytes[0], bytes.size(), + real_type, real_type, UNIVERSAL); + } + +/* +* Encode this object +*/ +DER_Encoder& DER_Encoder::encode(const byte bytes[], size_t length, + ASN1_Tag real_type) + { + return encode(bytes, length, real_type, real_type, UNIVERSAL); + } + +/* +* DER encode a BOOLEAN +*/ +DER_Encoder& DER_Encoder::encode(bool is_true, + ASN1_Tag type_tag, ASN1_Tag class_tag) + { + byte val = is_true ? 0xFF : 0x00; + return add_object(type_tag, class_tag, &val, 1); + } + +/* +* DER encode a small INTEGER +*/ +DER_Encoder& DER_Encoder::encode(size_t n, + ASN1_Tag type_tag, ASN1_Tag class_tag) + { + return encode(BigInt(n), type_tag, class_tag); + } + +/* +* DER encode an INTEGER +*/ +DER_Encoder& DER_Encoder::encode(const BigInt& n, + ASN1_Tag type_tag, ASN1_Tag class_tag) + { + if(n == 0) + return add_object(type_tag, class_tag, 0); + + bool extra_zero = (n.bits() % 8 == 0); + secure_vector<byte> contents(extra_zero + n.bytes()); + BigInt::encode(&contents[extra_zero], n); + if(n < 0) + { + for(size_t i = 0; i != contents.size(); ++i) + contents[i] = ~contents[i]; + for(size_t i = contents.size(); i > 0; --i) + if(++contents[i-1]) + break; + } + + return add_object(type_tag, class_tag, contents); + } + +/* +* DER encode an OCTET STRING or BIT STRING +*/ +DER_Encoder& DER_Encoder::encode(const secure_vector<byte>& bytes, + ASN1_Tag real_type, + ASN1_Tag type_tag, ASN1_Tag class_tag) + { + return encode(&bytes[0], bytes.size(), + real_type, type_tag, class_tag); + } + +/* +* DER encode an OCTET STRING or BIT STRING +*/ +DER_Encoder& DER_Encoder::encode(const std::vector<byte>& bytes, + ASN1_Tag real_type, + ASN1_Tag type_tag, ASN1_Tag class_tag) + { + return encode(&bytes[0], bytes.size(), + real_type, type_tag, class_tag); + } + +/* +* DER encode an OCTET STRING or BIT STRING +*/ +DER_Encoder& DER_Encoder::encode(const byte bytes[], size_t length, + ASN1_Tag real_type, + ASN1_Tag type_tag, ASN1_Tag class_tag) + { + if(real_type != OCTET_STRING && real_type != BIT_STRING) + throw Invalid_Argument("DER_Encoder: Invalid tag for byte/bit string"); + + if(real_type == BIT_STRING) + { + secure_vector<byte> encoded; + encoded.push_back(0); + encoded += std::make_pair(bytes, length); + return add_object(type_tag, class_tag, encoded); + } + else + return add_object(type_tag, class_tag, bytes, length); + } + +/* +* Conditionally write some values to the stream +*/ +DER_Encoder& DER_Encoder::encode_if(bool cond, DER_Encoder& codec) + { + if(cond) + return raw_bytes(codec.get_contents()); + return (*this); + } + +DER_Encoder& DER_Encoder::encode_if(bool cond, const ASN1_Object& obj) + { + if(cond) + encode(obj); + return (*this); + } + +/* +* Request for an object to encode itself +*/ +DER_Encoder& DER_Encoder::encode(const ASN1_Object& obj) + { + obj.encode_into(*this); + return (*this); + } + +/* +* Write the encoding of the byte(s) +*/ +DER_Encoder& DER_Encoder::add_object(ASN1_Tag type_tag, ASN1_Tag class_tag, + const byte rep[], size_t length) + { + secure_vector<byte> buffer; + buffer += encode_tag(type_tag, class_tag); + buffer += encode_length(length); + buffer += std::make_pair(rep, length); + + return raw_bytes(buffer); + } + +/* +* Write the encoding of the byte(s) +*/ +DER_Encoder& DER_Encoder::add_object(ASN1_Tag type_tag, ASN1_Tag class_tag, + const std::string& rep_str) + { + const byte* rep = reinterpret_cast<const byte*>(rep_str.data()); + const size_t rep_len = rep_str.size(); + return add_object(type_tag, class_tag, rep, rep_len); + } + +/* +* Write the encoding of the byte +*/ +DER_Encoder& DER_Encoder::add_object(ASN1_Tag type_tag, + ASN1_Tag class_tag, byte rep) + { + return add_object(type_tag, class_tag, &rep, 1); + } + +} |