diff options
Diffstat (limited to 'src/ber_dec.cpp')
| -rw-r--r-- | src/ber_dec.cpp | 211 |
1 files changed, 204 insertions, 7 deletions
diff --git a/src/ber_dec.cpp b/src/ber_dec.cpp index f9550fc83..51bc8f989 100644 --- a/src/ber_dec.cpp +++ b/src/ber_dec.cpp @@ -4,7 +4,7 @@ *************************************************/ #include <botan/ber_dec.h> -#include <botan/asn1_int.h> +#include <botan/bigint.h> #include <botan/bit_ops.h> namespace Botan { @@ -133,6 +133,15 @@ u32bit find_eoc(DataSource* ber) } /************************************************* +* 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 @@ -145,32 +154,34 @@ bool BER_Decoder::more_items() const /************************************************* * Verify that no bytes remain in the source * *************************************************/ -void BER_Decoder::verify_end() const +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); } /************************************************* -* Return all the bytes remaining in the source * +* Save all the bytes remaining in the source * *************************************************/ -SecureVector<byte> BER_Decoder::get_remaining() +BER_Decoder& BER_Decoder::raw_bytes(MemoryRegion<byte>& out) { - SecureVector<byte> out; + out.destroy(); byte buf; while(source->read_byte(buf)) out.append(buf); - return out; + return (*this); } /************************************************* * Discard all the bytes remaining in the source * *************************************************/ -void BER_Decoder::discard_remaining() +BER_Decoder& BER_Decoder::discard_remaining() { byte buf; while(source->read_byte(buf)) ; + return (*this); } /************************************************* @@ -213,6 +224,30 @@ void BER_Decoder::push_back(const BER_Object& obj) } /************************************************* +* Begin decoding a CONSTRUCTED type * +*************************************************/ +BER_Decoder BER_Decoder::start_cons(ASN1_Tag type_tag) + { + BER_Object obj = get_next_object(); + obj.assert_is_a(type_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) @@ -220,6 +255,7 @@ BER_Decoder::BER_Decoder(DataSource& src) source = &src; owns = false; pushed.type_tag = pushed.class_tag = NO_OBJECT; + parent = 0; } /************************************************* @@ -230,6 +266,7 @@ 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; } /************************************************* @@ -240,6 +277,7 @@ 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; } /************************************************* @@ -255,6 +293,7 @@ BER_Decoder::BER_Decoder(const BER_Decoder& other) owns = true; } pushed.type_tag = pushed.class_tag = NO_OBJECT; + parent = 0; } /************************************************* @@ -267,4 +306,162 @@ BER_Decoder::~BER_Decoder() 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 = (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); + } + } |