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/*
* BER Decoder
* (C) 1999-2010 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/
#ifndef BOTAN_BER_DECODER_H_
#define BOTAN_BER_DECODER_H_
#include <botan/asn1_obj.h>
#include <botan/data_src.h>
namespace Botan {
/**
* BER Decoding Object
*/
class BOTAN_PUBLIC_API(2,0) BER_Decoder final
{
public:
BER_Object get_next_object();
std::vector<uint8_t> get_next_octet_string();
void push_back(const BER_Object& obj);
bool more_items() const;
BER_Decoder& verify_end();
BER_Decoder& discard_remaining();
BER_Decoder start_cons(ASN1_Tag type_tag, ASN1_Tag class_tag = UNIVERSAL);
BER_Decoder& end_cons();
BER_Decoder& get_next(BER_Object& ber);
/**
* Get next object and copy value to POD type
* Asserts value length is equal to POD type sizeof.
* Asserts Type tag and optional Class tag according to parameters.
* Copy value to POD type (struct, union, C-style array, std::array, etc.).
* @param out POD type reference where to copy object value
* @param type_tag ASN1_Tag enum to assert type on object read
* @param class_tag ASN1_Tag enum to assert class on object read (default: CONTEXT_SPECIFIC)
* @return this reference
*/
template <typename T>
BER_Decoder& get_next_value(T &out,
ASN1_Tag type_tag,
ASN1_Tag class_tag = CONTEXT_SPECIFIC)
{
static_assert(std::is_pod<T>::value, "Type must be POD");
BER_Object obj = get_next_object();
obj.assert_is_a(type_tag, class_tag);
if (obj.value.size() != sizeof(T))
throw BER_Decoding_Error(
"Size mismatch. Object value size is " +
std::to_string(obj.value.size()) +
"; Output type size is " +
std::to_string(sizeof(T)));
copy_mem(reinterpret_cast<uint8_t*>(&out), obj.value.data(), obj.value.size());
return (*this);
}
/*
* Save all the bytes remaining in the source
*/
template<typename Alloc>
BER_Decoder& raw_bytes(std::vector<uint8_t, Alloc>& out)
{
out.clear();
uint8_t buf;
while(m_source->read_byte(buf))
out.push_back(buf);
return (*this);
}
BER_Decoder& decode_null();
BER_Decoder& decode(bool& v);
BER_Decoder& decode(size_t& v);
BER_Decoder& decode(class BigInt& v);
/*
* BER decode a BIT STRING or OCTET STRING
*/
template<typename Alloc>
BER_Decoder& decode(std::vector<uint8_t, Alloc>& out, ASN1_Tag real_type)
{
return decode(out, real_type, real_type, UNIVERSAL);
}
BER_Decoder& decode(bool& v,
ASN1_Tag type_tag,
ASN1_Tag class_tag = CONTEXT_SPECIFIC);
BER_Decoder& decode(size_t& v,
ASN1_Tag type_tag,
ASN1_Tag class_tag = CONTEXT_SPECIFIC);
BER_Decoder& decode(class BigInt& v,
ASN1_Tag type_tag,
ASN1_Tag class_tag = CONTEXT_SPECIFIC);
BER_Decoder& decode(std::vector<uint8_t>& v,
ASN1_Tag real_type,
ASN1_Tag type_tag,
ASN1_Tag class_tag = CONTEXT_SPECIFIC);
BER_Decoder& decode(secure_vector<uint8_t>& v,
ASN1_Tag real_type,
ASN1_Tag type_tag,
ASN1_Tag class_tag = CONTEXT_SPECIFIC);
BER_Decoder& decode(class ASN1_Object& obj,
ASN1_Tag type_tag = NO_OBJECT,
ASN1_Tag class_tag = NO_OBJECT);
BER_Decoder& decode_octet_string_bigint(class BigInt& b);
uint64_t decode_constrained_integer(ASN1_Tag type_tag,
ASN1_Tag class_tag,
size_t T_bytes);
template<typename T> BER_Decoder& decode_integer_type(T& out)
{
return decode_integer_type<T>(out, INTEGER, UNIVERSAL);
}
template<typename T>
BER_Decoder& decode_integer_type(T& out,
ASN1_Tag type_tag,
ASN1_Tag class_tag = CONTEXT_SPECIFIC)
{
out = static_cast<T>(decode_constrained_integer(type_tag, class_tag, sizeof(out)));
return (*this);
}
template<typename T>
BER_Decoder& decode_optional(T& out,
ASN1_Tag type_tag,
ASN1_Tag class_tag,
const T& default_value = T());
template<typename T>
BER_Decoder& decode_optional_implicit(
T& out,
ASN1_Tag type_tag,
ASN1_Tag class_tag,
ASN1_Tag real_type,
ASN1_Tag real_class,
const T& default_value = T());
template<typename T>
BER_Decoder& decode_list(std::vector<T>& out,
ASN1_Tag type_tag = SEQUENCE,
ASN1_Tag class_tag = UNIVERSAL);
template<typename T>
BER_Decoder& decode_and_check(const T& expected,
const std::string& error_msg)
{
T actual;
decode(actual);
if(actual != expected)
throw Decoding_Error(error_msg);
return (*this);
}
/*
* Decode an OPTIONAL string type
*/
template<typename Alloc>
BER_Decoder& decode_optional_string(std::vector<uint8_t, Alloc>& out,
ASN1_Tag real_type,
uint16_t type_no,
ASN1_Tag class_tag = CONTEXT_SPECIFIC)
{
BER_Object obj = get_next_object();
ASN1_Tag type_tag = static_cast<ASN1_Tag>(type_no);
if(obj.type_tag == type_tag && obj.class_tag == class_tag)
{
if((class_tag & CONSTRUCTED) && (class_tag & CONTEXT_SPECIFIC))
BER_Decoder(obj.value).decode(out, real_type).verify_end();
else
{
push_back(obj);
decode(out, real_type, type_tag, class_tag);
}
}
else
{
out.clear();
push_back(obj);
}
return (*this);
}
BER_Decoder& operator=(const BER_Decoder&) = delete;
explicit BER_Decoder(DataSource&);
BER_Decoder(const uint8_t[], size_t);
explicit BER_Decoder(const secure_vector<uint8_t>&);
explicit BER_Decoder(const std::vector<uint8_t>& vec);
BER_Decoder(const BER_Decoder&);
private:
BER_Decoder* m_parent;
BER_Object m_pushed;
// either m_data_src.get() or an unowned pointer
DataSource* m_source;
mutable std::unique_ptr<DataSource> m_data_src;
};
/*
* Decode an OPTIONAL or DEFAULT element
*/
template<typename T>
BER_Decoder& BER_Decoder::decode_optional(T& out,
ASN1_Tag type_tag,
ASN1_Tag class_tag,
const T& default_value)
{
BER_Object obj = get_next_object();
if(obj.type_tag == type_tag && obj.class_tag == class_tag)
{
if((class_tag & CONSTRUCTED) && (class_tag & CONTEXT_SPECIFIC))
BER_Decoder(obj.value).decode(out).verify_end();
else
{
push_back(obj);
decode(out, type_tag, class_tag);
}
}
else
{
out = default_value;
push_back(obj);
}
return (*this);
}
/*
* Decode an OPTIONAL or DEFAULT element
*/
template<typename T>
BER_Decoder& BER_Decoder::decode_optional_implicit(
T& out,
ASN1_Tag type_tag,
ASN1_Tag class_tag,
ASN1_Tag real_type,
ASN1_Tag real_class,
const T& default_value)
{
BER_Object obj = get_next_object();
if(obj.type_tag == type_tag && obj.class_tag == class_tag)
{
obj.type_tag = real_type;
obj.class_tag = real_class;
push_back(obj);
decode(out, real_type, real_class);
}
else
{
out = default_value;
push_back(obj);
}
return (*this);
}
/*
* Decode a list of homogenously typed values
*/
template<typename T>
BER_Decoder& BER_Decoder::decode_list(std::vector<T>& vec,
ASN1_Tag type_tag,
ASN1_Tag class_tag)
{
BER_Decoder list = start_cons(type_tag, class_tag);
while(list.more_items())
{
T value;
list.decode(value);
vec.push_back(value);
}
list.end_cons();
return (*this);
}
}
#endif
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