diff options
Diffstat (limited to 'botan/src/asn1/ber_dec.cpp')
| -rw-r--r-- | botan/src/asn1/ber_dec.cpp | 471 |
1 files changed, 0 insertions, 471 deletions
diff --git a/botan/src/asn1/ber_dec.cpp b/botan/src/asn1/ber_dec.cpp deleted file mode 100644 index ce60466..0000000 --- a/botan/src/asn1/ber_dec.cpp +++ /dev/null @@ -1,471 +0,0 @@ -/* -* BER Decoder -* (C) 1999-2008 Jack Lloyd -* -* Distributed under the terms of the Botan license -*/ - -#include <botan/ber_dec.h> -#include <botan/bigint.h> -#include <botan/loadstor.h> - -namespace Botan { - -namespace { - -/* -* BER decode an ASN.1 type tag -*/ -u32bit decode_tag(DataSource* ber, ASN1_Tag& type_tag, ASN1_Tag& class_tag) - { - byte b; - if(!ber->read_byte(b)) - { - class_tag = type_tag = NO_OBJECT; - return 0; - } - - if((b & 0x1F) != 0x1F) - { - type_tag = ASN1_Tag(b & 0x1F); - class_tag = ASN1_Tag(b & 0xE0); - return 1; - } - - u32bit tag_bytes = 1; - class_tag = ASN1_Tag(b & 0xE0); - - u32bit tag_buf = 0; - while(true) - { - if(!ber->read_byte(b)) - throw BER_Decoding_Error("Long-form tag truncated"); - if(tag_buf & 0xFF000000) - throw BER_Decoding_Error("Long-form tag overflowed 32 bits"); - ++tag_bytes; - tag_buf = (tag_buf << 7) | (b & 0x7F); - if((b & 0x80) == 0) break; - } - type_tag = ASN1_Tag(tag_buf); - return tag_bytes; - } - -/* -* Find the EOC marker -*/ -u32bit find_eoc(DataSource*); - -/* -* BER decode an ASN.1 length field -*/ -u32bit decode_length(DataSource* ber, u32bit& field_size) - { - byte b; - if(!ber->read_byte(b)) - throw BER_Decoding_Error("Length field not found"); - field_size = 1; - if((b & 0x80) == 0) - return b; - - field_size += (b & 0x7F); - if(field_size == 1) return find_eoc(ber); - if(field_size > 5) - throw BER_Decoding_Error("Length field is too large"); - - u32bit length = 0; - - for(u32bit j = 0; j != field_size - 1; ++j) - { - if(get_byte(0, length) != 0) - throw BER_Decoding_Error("Field length overflow"); - if(!ber->read_byte(b)) - throw BER_Decoding_Error("Corrupted length field"); - length = (length << 8) | b; - } - return length; - } - -/* -* BER decode an ASN.1 length field -*/ -u32bit decode_length(DataSource* ber) - { - u32bit dummy; - return decode_length(ber, dummy); - } - -/* -* Find the EOC marker -*/ -u32bit find_eoc(DataSource* ber) - { - SecureVector<byte> buffer(DEFAULT_BUFFERSIZE), data; - - while(true) - { - const u32bit got = ber->peek(buffer, buffer.size(), data.size()); - if(got == 0) - break; - data.append(buffer, got); - } - - DataSource_Memory source(data); - data.destroy(); - - u32bit length = 0; - while(true) - { - ASN1_Tag type_tag, class_tag; - u32bit tag_size = decode_tag(&source, type_tag, class_tag); - if(type_tag == NO_OBJECT) - break; - - u32bit length_size = 0; - u32bit item_size = decode_length(&source, length_size); - source.discard_next(item_size); - - length += item_size + length_size + tag_size; - - if(type_tag == EOC) - break; - } - return length; - } - -} - -/* -* Check a type invariant on BER data -*/ -void BER_Object::assert_is_a(ASN1_Tag type_tag, ASN1_Tag class_tag) - { - if(this->type_tag != type_tag || this->class_tag != class_tag) - throw BER_Decoding_Error("Tag mismatch when decoding"); - } - -/* -* Check if more objects are there -*/ -bool BER_Decoder::more_items() const - { - if(source->end_of_data() && (pushed.type_tag == NO_OBJECT)) - return false; - return true; - } - -/* -* Verify that no bytes remain in the source -*/ -BER_Decoder& BER_Decoder::verify_end() - { - if(!source->end_of_data() || (pushed.type_tag != NO_OBJECT)) - throw Invalid_State("BER_Decoder::verify_end called, but data remains"); - return (*this); - } - -/* -* Save all the bytes remaining in the source -*/ -BER_Decoder& BER_Decoder::raw_bytes(MemoryRegion<byte>& out) - { - out.destroy(); - byte buf; - while(source->read_byte(buf)) - out.append(buf); - return (*this); - } - -/* -* Discard all the bytes remaining in the source -*/ -BER_Decoder& BER_Decoder::discard_remaining() - { - byte buf; - while(source->read_byte(buf)) - ; - return (*this); - } - -/* -* Return the BER encoding of the next object -*/ -BER_Object BER_Decoder::get_next_object() - { - BER_Object next; - - if(pushed.type_tag != NO_OBJECT) - { - next = pushed; - pushed.class_tag = pushed.type_tag = NO_OBJECT; - return next; - } - - decode_tag(source, next.type_tag, next.class_tag); - if(next.type_tag == NO_OBJECT) - return next; - - u32bit length = decode_length(source); - next.value.create(length); - if(source->read(next.value, length) != length) - throw BER_Decoding_Error("Value truncated"); - - if(next.type_tag == EOC && next.class_tag == UNIVERSAL) - return get_next_object(); - - return next; - } - -/* -* Push a object back into the stream -*/ -void BER_Decoder::push_back(const BER_Object& obj) - { - if(pushed.type_tag != NO_OBJECT) - throw Invalid_State("BER_Decoder: Only one push back is allowed"); - pushed = obj; - } - -/* -* Begin decoding a CONSTRUCTED type -*/ -BER_Decoder BER_Decoder::start_cons(ASN1_Tag type_tag, - ASN1_Tag class_tag) - { - BER_Object obj = get_next_object(); - obj.assert_is_a(type_tag, ASN1_Tag(class_tag | CONSTRUCTED)); - - BER_Decoder result(obj.value, obj.value.size()); - result.parent = this; - return result; - } - -/* -* Finish decoding a CONSTRUCTED type -*/ -BER_Decoder& BER_Decoder::end_cons() - { - if(!parent) - throw Invalid_State("BER_Decoder::end_cons called with NULL parent"); - if(!source->end_of_data()) - throw Decoding_Error("BER_Decoder::end_cons called with data left"); - return (*parent); - } - -/* -* BER_Decoder Constructor -*/ -BER_Decoder::BER_Decoder(DataSource& src) - { - source = &src; - owns = false; - pushed.type_tag = pushed.class_tag = NO_OBJECT; - parent = 0; - } - -/* -* BER_Decoder Constructor - */ -BER_Decoder::BER_Decoder(const byte data[], u32bit length) - { - source = new DataSource_Memory(data, length); - owns = true; - pushed.type_tag = pushed.class_tag = NO_OBJECT; - parent = 0; - } - -/* -* BER_Decoder Constructor -*/ -BER_Decoder::BER_Decoder(const MemoryRegion<byte>& data) - { - source = new DataSource_Memory(data); - owns = true; - pushed.type_tag = pushed.class_tag = NO_OBJECT; - parent = 0; - } - -/* -* BER_Decoder Copy Constructor -*/ -BER_Decoder::BER_Decoder(const BER_Decoder& other) - { - source = other.source; - owns = false; - if(other.owns) - { - other.owns = false; - owns = true; - } - pushed.type_tag = pushed.class_tag = NO_OBJECT; - parent = other.parent; - } - -/* -* BER_Decoder Destructor -*/ -BER_Decoder::~BER_Decoder() - { - if(owns) - delete source; - source = 0; - } - -/* -* Request for an object to decode itself -*/ -BER_Decoder& BER_Decoder::decode(ASN1_Object& obj) - { - obj.decode_from(*this); - return (*this); - } - -/* -* Decode a BER encoded NULL -*/ -BER_Decoder& BER_Decoder::decode_null() - { - BER_Object obj = get_next_object(); - obj.assert_is_a(NULL_TAG, UNIVERSAL); - if(obj.value.size()) - throw BER_Decoding_Error("NULL object had nonzero size"); - return (*this); - } - -/* -* Decode a BER encoded BOOLEAN -*/ -BER_Decoder& BER_Decoder::decode(bool& out) - { - return decode(out, BOOLEAN, UNIVERSAL); - } - -/* -* Decode a small BER encoded INTEGER -*/ -BER_Decoder& BER_Decoder::decode(u32bit& out) - { - return decode(out, INTEGER, UNIVERSAL); - } - -/* -* Decode a BER encoded INTEGER -*/ -BER_Decoder& BER_Decoder::decode(BigInt& out) - { - return decode(out, INTEGER, UNIVERSAL); - } - -/* -* Decode a BER encoded BOOLEAN -*/ -BER_Decoder& BER_Decoder::decode(bool& out, - ASN1_Tag type_tag, ASN1_Tag class_tag) - { - BER_Object obj = get_next_object(); - obj.assert_is_a(type_tag, class_tag); - - if(obj.value.size() != 1) - throw BER_Decoding_Error("BER boolean value had invalid size"); - - out = (obj.value[0]) ? true : false; - return (*this); - } - -/* -* Decode a small BER encoded INTEGER -*/ -BER_Decoder& BER_Decoder::decode(u32bit& out, - ASN1_Tag type_tag, ASN1_Tag class_tag) - { - BigInt integer; - decode(integer, type_tag, class_tag); - out = integer.to_u32bit(); - return (*this); - } - -/* -* Decode a BER encoded INTEGER -*/ -BER_Decoder& BER_Decoder::decode(BigInt& out, - ASN1_Tag type_tag, ASN1_Tag class_tag) - { - BER_Object obj = get_next_object(); - obj.assert_is_a(type_tag, class_tag); - - if(obj.value.is_empty()) - out = 0; - else - { - const bool negative = (obj.value[0] & 0x80) ? true : false; - - if(negative) - { - for(u32bit j = obj.value.size(); j > 0; --j) - if(obj.value[j-1]--) - break; - for(u32bit j = 0; j != obj.value.size(); ++j) - obj.value[j] = ~obj.value[j]; - } - - out = BigInt(obj.value, obj.value.size()); - - if(negative) - out.flip_sign(); - } - - return (*this); - } - -/* -* BER decode a BIT STRING or OCTET STRING -*/ -BER_Decoder& BER_Decoder::decode(MemoryRegion<byte>& out, ASN1_Tag real_type) - { - return decode(out, real_type, real_type, UNIVERSAL); - } - -/* -* BER decode a BIT STRING or OCTET STRING -*/ -BER_Decoder& BER_Decoder::decode(MemoryRegion<byte>& buffer, - ASN1_Tag real_type, - ASN1_Tag type_tag, ASN1_Tag class_tag) - { - if(real_type != OCTET_STRING && real_type != BIT_STRING) - throw BER_Bad_Tag("Bad tag for {BIT,OCTET} STRING", real_type); - - BER_Object obj = get_next_object(); - obj.assert_is_a(type_tag, class_tag); - - if(real_type == OCTET_STRING) - buffer = obj.value; - else - { - if(obj.value[0] >= 8) - throw BER_Decoding_Error("Bad number of unused bits in BIT STRING"); - buffer.set(obj.value + 1, obj.value.size() - 1); - } - return (*this); - } - -/* -* Decode an OPTIONAL string type -*/ -BER_Decoder& BER_Decoder::decode_optional_string(MemoryRegion<byte>& out, - ASN1_Tag real_type, - u16bit type_no) - { - BER_Object obj = get_next_object(); - - ASN1_Tag type_tag = static_cast<ASN1_Tag>(type_no); - - out.clear(); - push_back(obj); - - if(obj.type_tag == type_tag && obj.class_tag == CONTEXT_SPECIFIC) - decode(out, real_type, type_tag, CONTEXT_SPECIFIC); - - return (*this); - } - -} |
