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// bson_validate.cpp
/* Copyright 2012 10gen Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "mongo/bson/bson_validate.h"
#include "mongo/bson/oid.h"
namespace mongo {
namespace {
class Buffer {
public:
Buffer( const char* buffer, uint64_t maxLength )
: _buffer( buffer ), _position( 0 ), _maxLength( maxLength ) {
}
template<typename N>
bool readNumber( N* out ) {
if ( ( _position + sizeof(N) ) > _maxLength )
return false;
if ( out ) {
const N* temp = reinterpret_cast<const N*>(_buffer + _position);
*out = *temp;
}
_position += sizeof(N);
return true;
}
Status readCString( StringData* out ) {
const void* x = memchr( _buffer + _position, 0, _maxLength - _position );
if ( !x )
return Status( ErrorCodes::InvalidBSON, "no end of c-string" );
uint64_t len = static_cast<uint64_t>( static_cast<const char*>(x) - ( _buffer + _position ) );
StringData data( _buffer + _position, len );
_position += len + 1;
if ( out ) {
*out = data;
}
return Status::OK();
}
Status readUTF8String( StringData* out ) {
int sz;
if ( !readNumber<int>( &sz ) )
return Status( ErrorCodes::InvalidBSON, "invalid bson" );
if ( out ) {
*out = StringData( _buffer + _position, sz );
}
if ( !skip( sz - 1 ) )
return Status( ErrorCodes::InvalidBSON, "invalid bson" );
char c;
if ( !readNumber<char>( &c ) )
return Status( ErrorCodes::InvalidBSON, "invalid bson" );
if ( c != 0 )
return Status( ErrorCodes::InvalidBSON, "not null terminate string" );
return Status::OK();
}
bool skip( uint64_t sz ) {
_position += sz;
return _position < _maxLength;
}
uint64_t position() const {
return _position;
}
private:
const char* _buffer;
uint64_t _position;
uint64_t _maxLength;
};
Status validateBSONInternal( Buffer* buffer, int* bsonLength ) {
const int start = buffer->position();
int supposedSize;
if ( !buffer->readNumber<int>(&supposedSize) )
return Status( ErrorCodes::InvalidBSON, "bson size is larger than buffer size" );
Status status = Status::OK();
while ( true ) {
char type;
if ( !buffer->readNumber<char>(&type) )
return Status( ErrorCodes::InvalidBSON, "invalid bson" );
if ( type == EOO )
break;
StringData name;
status = buffer->readCString( &name );
if ( !status.isOK() )
return status;
switch ( type ) {
case MinKey:
case MaxKey:
case jstNULL:
case Undefined:
break;
case jstOID:
if ( !buffer->skip( sizeof(OID) ) )
return Status( ErrorCodes::InvalidBSON, "invalid bson" );
break;
case NumberInt:
if ( !buffer->skip( sizeof(int32_t) ) )
return Status( ErrorCodes::InvalidBSON, "invalid bson" );
break;
case Bool:
if ( !buffer->skip( sizeof(int8_t) ) )
return Status( ErrorCodes::InvalidBSON, "invalid bson" );
break;
case NumberDouble:
case NumberLong:
case Timestamp:
case Date:
if ( !buffer->skip( sizeof(int64_t) ) )
return Status( ErrorCodes::InvalidBSON, "invalid bson" );
break;
case DBRef:
status = buffer->readUTF8String( NULL );
if ( !status.isOK() )
return status;
buffer->skip( sizeof(OID) );
break;
case CodeWScope: {
int myStart = buffer->position();
int sz;
if ( !buffer->readNumber<int>( &sz ) )
return Status( ErrorCodes::InvalidBSON, "invalid bson" );
status = buffer->readUTF8String( NULL );
if ( !status.isOK() )
return status;
status = validateBSONInternal( buffer, NULL );
if ( !status.isOK() )
return status;
if ( sz != static_cast<int>(buffer->position() - myStart) )
return Status( ErrorCodes::InvalidBSON, "CodeWScope len is wrong" );
break;
}
case RegEx:
status = buffer->readCString( NULL );
if ( !status.isOK() )
return status;
status = buffer->readCString( NULL );
if ( !status.isOK() )
return status;
break;
case Code:
case Symbol:
case String:
status = buffer->readUTF8String( NULL );
if ( !status.isOK() )
return status;
break;
case BinData: {
int sz;
if ( !buffer->readNumber<int>( &sz ) )
return Status( ErrorCodes::InvalidBSON, "invalid bson" );
if ( !buffer->skip( 1 + sz ) )
return Status( ErrorCodes::InvalidBSON, "invalid bson" );
break;
}
case Object:
case Array:
status = validateBSONInternal( buffer, NULL );
if ( !status.isOK() )
return status;
break;
default:
return Status( ErrorCodes::InvalidBSON, "invalid bson type" );
}
}
const int end = buffer->position();
if ( end - start != supposedSize )
return Status( ErrorCodes::InvalidBSON, "bson length doesn't match what we found" );
if ( bsonLength )
*bsonLength = supposedSize;
return Status::OK();
}
}
Status validateBSON( const char* originalBuffer, uint64_t maxLength, int* bsonLength ) {
if ( maxLength < 5 ) {
return Status( ErrorCodes::InvalidBSON, "bson data has to be at least 5 bytes" );
}
Buffer buf( originalBuffer, maxLength );
return validateBSONInternal( &buf, bsonLength );
}
}
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