diff options
author | lloyd <[email protected]> | 2006-05-18 18:33:19 +0000 |
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committer | lloyd <[email protected]> | 2006-05-18 18:33:19 +0000 |
commit | a2c99d3270eb73ef2db5704fc54356c6b75096f8 (patch) | |
tree | ad3d6c4fcc8dd0f403f8105598943616246fe172 /src/der_enc.cpp |
Initial checkin1.5.6
Diffstat (limited to 'src/der_enc.cpp')
-rw-r--r-- | src/der_enc.cpp | 479 |
1 files changed, 479 insertions, 0 deletions
diff --git a/src/der_enc.cpp b/src/der_enc.cpp new file mode 100644 index 000000000..c4a7245ff --- /dev/null +++ b/src/der_enc.cpp @@ -0,0 +1,479 @@ +/************************************************* +* DER Encoder Source File * +* (C) 1999-2006 The Botan Project * +*************************************************/ + +#include <botan/der_enc.h> +#include <botan/asn1_int.h> +#include <botan/bigint.h> +#include <botan/bit_ops.h> +#include <botan/parsing.h> +#include <algorithm> + +namespace Botan { + +namespace { + +/************************************************* +* DER encode an ASN.1 type tag * +*************************************************/ +SecureVector<byte> encode_tag(ASN1_Tag type_tag, ASN1_Tag class_tag) + { + if((class_tag | 0xE0) != 0xE0) + throw Encoding_Error("DER_Encoder: Invalid class tag " + + to_string(class_tag)); + + SecureVector<byte> encoded_tag; + if(type_tag <= 30) + encoded_tag.append((byte)(type_tag | class_tag)); + else + { + u32bit blocks = high_bit(type_tag) + 6; + blocks = (blocks - (blocks % 7)) / 7; + + encoded_tag.append(class_tag | 0x1F); + for(u32bit k = 0; k != blocks - 1; ++k) + encoded_tag.append(0x80 | ((type_tag >> 7*(blocks-k-1)) & 0x7F)); + encoded_tag.append(type_tag & 0x7F); + } + + return encoded_tag; + } + +/************************************************* +* DER encode an ASN.1 length field * +*************************************************/ +SecureVector<byte> encode_length(u32bit length) + { + SecureVector<byte> encoded_length; + if(length <= 127) + encoded_length.append((byte)length); + else + { + const u32bit top_byte = significant_bytes(length); + encoded_length.append((byte)(0x80 | top_byte)); + for(u32bit j = 4-top_byte; j != 4; ++j) + encoded_length.append(get_byte(j, length)); + } + return encoded_length; + } + +/************************************************* +* A comparison functor for sorting SET objects * +*************************************************/ +class DER_Cmp + { + public: + bool operator()(const MemoryRegion<byte>&, + const MemoryRegion<byte>&) const; + }; + +/************************************************* +* Compare two encodings, as specified by X.690 * +*************************************************/ +bool DER_Cmp::operator()(const MemoryRegion<byte>& a, + const MemoryRegion<byte>& b) const + { + if(a.size() < b.size()) return true; + if(a.size() > b.size()) return false; + + for(u32bit j = 0; j != a.size(); ++j) + { + if(a[j] < b[j]) return true; + if(a[j] > b[j]) return false; + } + return false; + } + +} + +/************************************************* +* Return the encoded SEQUENCE/SET * +*************************************************/ +SecureVector<byte> DER_Encoder::DER_Sequence::get_contents() + { + const ASN1_Tag real_class_tag = ASN1_Tag(class_tag | CONSTRUCTED); + + SecureVector<byte> encoded_tag = encode_tag(type_tag, real_class_tag); + + if(is_a_set) + { + std::sort(set_contents.begin(), set_contents.end(), DER_Cmp()); + for(u32bit j = 0; j != set_contents.size(); ++j) + contents.append(set_contents[j]); + set_contents.clear(); + } + + SecureVector<byte> encoded_length = encode_length(contents.size()); + + SecureVector<byte> retval; + retval.append(encoded_tag); + retval.append(encoded_length); + retval.append(contents); + contents.destroy(); + return retval; + } + +/************************************************* +* Add an encoded value to the SEQUENCE/SET * +*************************************************/ +void DER_Encoder::DER_Sequence::add_bytes(const byte data[], u32bit length) + { + if(is_a_set) + { + set_contents.push_back(SecureVector<byte>(data, length)); + } + else + contents.append(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, bool b) : + type_tag(t1), class_tag(t2), is_a_set(b) + { + } + +/************************************************* +* Return the encoded contents * +*************************************************/ +SecureVector<byte> DER_Encoder::get_contents() + { + if(sequence_level != 0) + throw Invalid_State("DER_Encoder: Sequence hasn't been marked done"); + + SecureVector<byte> retval; + retval = contents; + contents.destroy(); + return retval; + } + +/************************************************* +* Start a new ASN.1 SEQUENCE/SET/EXPLICIT * +*************************************************/ +DER_Encoder& DER_Encoder::start_cons(ASN1_Tag type_tag, ASN1_Tag class_tag, + bool is_a_set) + { + ++sequence_level; + subsequences.push_back(DER_Sequence(type_tag, class_tag, is_a_set)); + return (*this); + } + +/************************************************* +* Finish the current ASN.1 SEQUENCE/SET/EXPLICIT * +*************************************************/ +DER_Encoder& DER_Encoder::end_cons(ASN1_Tag type_tag, ASN1_Tag class_tag) + { + if(sequence_level == 0) + throw Invalid_State("DER_Encoder::end_cons: No such sequence"); + sequence_level--; + if(subsequences[sequence_level].tag_of() != ASN1_Tag(type_tag | class_tag)) + throw Invalid_Argument("DER_Encoder::end_cons: Tag mismatch"); + + SecureVector<byte> seq = subsequences[sequence_level].get_contents(); + subsequences.pop_back(); + add_raw_octets(seq); + return (*this); + } + +/************************************************* +* Start a new ASN.1 SEQUENCE * +*************************************************/ +DER_Encoder& DER_Encoder::start_sequence(ASN1_Tag type_tag, ASN1_Tag class_tag) + { + return start_cons(type_tag, class_tag, false); + } + +/************************************************* +* Finish the current ASN.1 SEQUENCE * +*************************************************/ +DER_Encoder& DER_Encoder::end_sequence(ASN1_Tag type_tag, ASN1_Tag class_tag) + { + return end_cons(type_tag, class_tag); + } + +/************************************************* +* Start a new ASN.1 SET * +*************************************************/ +DER_Encoder& DER_Encoder::start_set(ASN1_Tag type_tag, ASN1_Tag class_tag) + { + return start_cons(type_tag, class_tag, true); + } + +/************************************************* +* Finish the current ASN.1 SET * +*************************************************/ +DER_Encoder& DER_Encoder::end_set(ASN1_Tag type_tag, ASN1_Tag class_tag) + { + return end_cons(type_tag, class_tag); + } + +/************************************************* +* Start a new ASN.1 SEQUENCE * +*************************************************/ +DER_Encoder& DER_Encoder::start_sequence() + { + return start_sequence(SEQUENCE, UNIVERSAL); + } + +/************************************************* +* Finish the current ASN.1 SEQUENCE * +*************************************************/ +DER_Encoder& DER_Encoder::end_sequence() + { + return end_sequence(SEQUENCE, UNIVERSAL); + } + +/************************************************* +* Start a new ASN.1 SET * +*************************************************/ +DER_Encoder& DER_Encoder::start_set() + { + return start_set(SET, UNIVERSAL); + } + +/************************************************* +* Finish the current ASN.1 SET * +*************************************************/ +DER_Encoder& DER_Encoder::end_set() + { + return end_set(SET, UNIVERSAL); + } + +/************************************************* +* Start a new ASN.1 EXPLICIT encoding * +*************************************************/ +DER_Encoder& DER_Encoder::start_explicit(ASN1_Tag type_tag, ASN1_Tag class_tag) + { + return start_cons(type_tag, class_tag, false); + } + +/************************************************* +* Finish the current ASN.1 EXPLICIT encoding * +*************************************************/ +DER_Encoder& DER_Encoder::end_explicit(ASN1_Tag type_tag, ASN1_Tag class_tag) + { + return end_cons(type_tag, class_tag); + } + +/************************************************* +* Write raw octets into the stream * +*************************************************/ +DER_Encoder& DER_Encoder::add_raw_octets(const MemoryRegion<byte>& octets) + { + return add_raw_octets(octets.begin(), octets.size()); + } + +/************************************************* +* Write raw octets into the stream * +*************************************************/ +DER_Encoder& DER_Encoder::add_raw_octets(const byte octets[], u32bit length) + { + if(sequence_level == 0) + contents.append(octets, length); + else + subsequences[sequence_level-1].add_bytes(octets, length); + return (*this); + } + +/************************************************* +* Encode a NULL object * +*************************************************/ +DER_Encoder& DER_Encoder::encode_null() + { + return add_object(NULL_TAG, UNIVERSAL, 0, 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(u32bit 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 MemoryRegion<byte>& octets, + ASN1_Tag real_type) + { + return encode(octets.begin(), octets.size(), + real_type, real_type, UNIVERSAL); + } + +/************************************************* +* Encode this object * +*************************************************/ +DER_Encoder& DER_Encoder::encode(const byte octets[], u32bit length, + ASN1_Tag real_type) + { + return encode(octets, 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(u32bit 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); + SecureVector<byte> contents(extra_zero + n.bytes()); + BigInt::encode(contents.begin() + extra_zero, n); + if(n < 0) + { + for(u32bit j = 0; j != contents.size(); ++j) + contents[j] = ~contents[j]; + for(u32bit j = contents.size(); j > 0; --j) + if(++contents[j-1]) + break; + } + + return add_object(type_tag, class_tag, contents); + } + +/************************************************* +* DER encode an OCTET STRING or BIT STRING * +*************************************************/ +DER_Encoder& DER_Encoder::encode(const MemoryRegion<byte>& octets, + ASN1_Tag real_type, + ASN1_Tag type_tag, ASN1_Tag class_tag) + { + return encode(octets.begin(), octets.size(), + real_type, type_tag, class_tag); + } + +/************************************************* +* DER encode an OCTET STRING or BIT STRING * +*************************************************/ +DER_Encoder& DER_Encoder::encode(const byte octets[], u32bit 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) + { + SecureVector<byte> encoded; + encoded.append(0); + encoded.append(octets, length); + return add_object(type_tag, class_tag, encoded); + } + else + return add_object(type_tag, class_tag, octets, length); + } + +/************************************************* +* 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 octet(s) * +*************************************************/ +DER_Encoder& DER_Encoder::add_object(ASN1_Tag type_tag, ASN1_Tag class_tag, + const byte rep[], u32bit length) + { + SecureVector<byte> encoded_tag = encode_tag(type_tag, class_tag); + SecureVector<byte> encoded_length = encode_length(length); + + SecureVector<byte> buffer; + buffer.append(encoded_tag); + buffer.append(encoded_length); + buffer.append(rep, length); + + return add_raw_octets(buffer); + } + +/************************************************* +* Write the encoding of the octet(s) * +*************************************************/ +DER_Encoder& DER_Encoder::add_object(ASN1_Tag type_tag, ASN1_Tag class_tag, + const MemoryRegion<byte>& rep_buf) + { + const byte* rep = rep_buf.begin(); + const u32bit rep_len = rep_buf.size(); + return add_object(type_tag, class_tag, rep, rep_len); + } + +/************************************************* +* Write the encoding of the octet(s) * +*************************************************/ +DER_Encoder& DER_Encoder::add_object(ASN1_Tag type_tag, ASN1_Tag class_tag, + const std::string& rep_str) + { + const byte* rep = (const byte*)rep_str.c_str(); + const u32bit rep_len = rep_str.size(); + return add_object(type_tag, class_tag, rep, rep_len); + } + +/************************************************* +* Write the encoding of the octet * +*************************************************/ +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); + } + +/************************************************* +* DER_Encoder Constructor * +*************************************************/ +DER_Encoder::DER_Encoder() + { + sequence_level = 0; + } + +} |