RfidResearchGroup/proxmark3
1
1
Fork 0
mirror of https://github.com/RfidResearchGroup/proxmark3.git synced 2024-11-14 13:44:49 +08:00
Code Issues Projects Releases Packages Wiki Activity
proxmark3/client/deps/tinycbor/cborparser.c
Bjoern Kerler 81bc0bc2b9 Reorder client src directories
2020-04-16 10:53:24 +02:00

1395 lines
51 KiB
C
Raw Blame History

/****************************************************************************
**
** Copyright (C) 2017 Intel Corporation
**
** Permission is hereby granted, free of charge, to any person obtaining a copy
** of this software and associated documentation files (the "Software"), to deal
** in the Software without restriction, including without limitation the rights
** to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
** copies of the Software, and to permit persons to whom the Software is
** furnished to do so, subject to the following conditions:
**
** The above copyright notice and this permission notice shall be included in
** all copies or substantial portions of the Software.
**
** THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
** IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
** FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
** AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
** LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
** OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
** THE SOFTWARE.
**
****************************************************************************/
#ifndef _BSD_SOURCE
#define _BSD_SOURCE 1
#endif
#ifndef _DEFAULT_SOURCE
#define _DEFAULT_SOURCE 1
#endif
#ifndef __STDC_LIMIT_MACROS
# define __STDC_LIMIT_MACROS 1
#endif
#include "cbor.h"
#include "cborinternal_p.h"
#include "compilersupport_p.h"
#include <string.h>
/**
* \defgroup CborParsing Parsing CBOR streams
* \brief Group of functions used to parse CBOR streams.
*
* TinyCBOR provides functions for pull-based stream parsing of a CBOR-encoded
* payload. The main data type for the parsing is a CborValue, which behaves
* like an iterator and can be used to extract the encoded data. It is first
* initialized with a call to cbor_parser_init() and is usually used to extract
* exactly one item, most often an array or map.
*
* Nested CborValue objects can be parsed using cbor_value_enter_container().
* Each call to cbor_value_enter_container() must be matched by a call to
* cbor_value_leave_container(), with the exact same parameters.
*
* The example below initializes a CborParser object, begins the parsing with a
* CborValue and decodes a single integer:
*
* \code
* int extract_int(const uint8_t *buffer, size_t len)
* {
* CborParser parser;
* CborValue value;
* int result;
* cbor_parser_init(buffer, len, 0, &parser, &value);
* cbor_value_get_int(&value, &result);
* return result;
* }
* \endcode
*
* The code above does no error checking, which means it assumes the data comes
* from a source trusted to send one properly-encoded integer. The following
* example does the exact same operation, but includes error checking and
* returns 0 on parsing failure:
*
* \code
* int extract_int(const uint8_t *buffer, size_t len)
* {
* CborParser parser;
* CborValue value;
* int result;
* if (cbor_parser_init(buffer, len, 0, &parser, &value) != CborNoError)
* return 0;
* if (!cbor_value_is_integer(&value) ||
* cbor_value_get_int(&value, &result) != CborNoError)
* return 0;
* return result;
* }
* \endcode
*
* Note, in the example above, that one can't distinguish a parsing failure
* from an encoded value of zero. Reporting a parsing error is left as an
* exercise to the reader.
*
* The code above does not execute a range-check either: it is possible that
* the value decoded from the CBOR stream encodes a number larger than what can
* be represented in a variable of type \c{int}. If detecting that case is
* important, the code should call cbor_value_get_int_checked() instead.
*
* <h3 class="groupheader">Memory and parsing constraints</h3>
*
* TinyCBOR is designed to run with little memory and with minimal overhead.
* Except where otherwise noted, the parser functions always run on constant
* time (O(1)), do not recurse and never allocate memory (thus, stack usage is
* bounded and is O(1)).
*
* <h3 class="groupheader">Error handling and preconditions</h3>
*
* All functions operating on a CborValue return a CborError condition, with
* CborNoError standing for the normal situation in which no parsing error
* occurred. All functions may return parsing errors in case the stream cannot
* be decoded properly, be it due to corrupted data or due to reaching the end
* of the input buffer.
*
* Error conditions must not be ignored. All decoder functions have undefined
* behavior if called after an error has been reported, and may crash.
*
* Some functions are also documented to have preconditions, like
* cbor_value_get_int() requiring that the input be an integral value.
* Violation of preconditions also results in undefined behavior and the
* program may crash.
*/
/**
* \addtogroup CborParsing
* @{
*/
/**
* \struct CborValue
*
* This type contains one value parsed from the CBOR stream. Each CborValue
* behaves as an iterator in a StAX-style parser.
*
* \if privatedocs
* Implementation details: the CborValue contains these fields:
* \list
* \li ptr: pointer to the actual data
* \li flags: flags from the decoder
* \li extra: partially decoded integer value (0, 1 or 2 bytes)
* \li remaining: remaining items in this collection after this item or UINT32_MAX if length is unknown
* \endlist
* \endif
*/
static inline uint16_t get16(const uint8_t *ptr) {
uint16_t result;
memcpy(&result, ptr, sizeof(result));
return cbor_ntohs(result);
}
static inline uint32_t get32(const uint8_t *ptr) {
uint32_t result;
memcpy(&result, ptr, sizeof(result));
return cbor_ntohl(result);
}
static inline uint64_t get64(const uint8_t *ptr) {
uint64_t result;
memcpy(&result, ptr, sizeof(result));
return cbor_ntohll(result);
}
CborError CBOR_INTERNAL_API_CC _cbor_value_extract_number(const uint8_t **ptr, const uint8_t *end, uint64_t *len) {
size_t bytesNeeded;
uint8_t additional_information = **ptr & SmallValueMask;
++*ptr;
if (additional_information < Value8Bit) {
*len = additional_information;
return CborNoError;
}
if (unlikely(additional_information > Value64Bit))
return CborErrorIllegalNumber;
bytesNeeded = (size_t)(1 << (additional_information - Value8Bit));
if (unlikely(bytesNeeded > (size_t)(end - *ptr))) {
return CborErrorUnexpectedEOF;
} else if (bytesNeeded == 1) {
*len = (uint8_t)(*ptr)[0];
} else if (bytesNeeded == 2) {
*len = get16(*ptr);
} else if (bytesNeeded == 4) {
*len = get32(*ptr);
} else {
*len = get64(*ptr);
}
*ptr += bytesNeeded;
return CborNoError;
}
static CborError extract_length(const CborParser *parser, const uint8_t **ptr, size_t *len) {
uint64_t v;
CborError err = _cbor_value_extract_number(ptr, parser->end, &v);
if (err) {
*len = 0;
return err;
}
*len = (size_t)v;
if (v != *len)
return CborErrorDataTooLarge;
return CborNoError;
}
static bool is_fixed_type(uint8_t type) {
return type != CborTextStringType && type != CborByteStringType && type != CborArrayType &&
type != CborMapType;
}
static CborError preparse_value(CborValue *it) {
const CborParser *parser = it->parser;
/* are we at the end? */
if (it->ptr == parser->end)
return CborErrorUnexpectedEOF;
uint8_t descriptor = *it->ptr;
uint8_t type = descriptor & MajorTypeMask;
it->type = type;
it->flags = 0;
it->extra = (descriptor &= SmallValueMask);
if (descriptor > Value64Bit) {
if (unlikely(descriptor != IndefiniteLength))
return type == CborSimpleType ? CborErrorUnknownType : CborErrorIllegalNumber;
if (likely(!is_fixed_type(type))) {
/* special case */
it->flags |= CborIteratorFlag_UnknownLength;
it->type = type;
return CborNoError;
}
return type == CborSimpleType ? CborErrorUnexpectedBreak : CborErrorIllegalNumber;
}
size_t bytesNeeded = descriptor < Value8Bit ? 0 : (1 << (descriptor - Value8Bit));
if (bytesNeeded + 1 > (size_t)(parser->end - it->ptr))
return CborErrorUnexpectedEOF;
uint8_t majortype = type >> MajorTypeShift;
if (majortype == NegativeIntegerType) {
it->flags |= CborIteratorFlag_NegativeInteger;
it->type = CborIntegerType;
} else if (majortype == SimpleTypesType) {
switch (descriptor) {
case FalseValue:
it->extra = false;
it->type = CborBooleanType;
break;
case SinglePrecisionFloat:
case DoublePrecisionFloat:
it->flags |= CborIteratorFlag_IntegerValueTooLarge;
/* fall through */
case TrueValue:
case NullValue:
case UndefinedValue:
case HalfPrecisionFloat:
it->type = *it->ptr;
break;
case SimpleTypeInNextByte:
it->extra = (uint8_t)it->ptr[1];
#ifndef CBOR_PARSER_NO_STRICT_CHECKS
if (unlikely(it->extra < 32)) {
it->type = CborInvalidType;
return CborErrorIllegalSimpleType;
}
#endif
break;
case 28:
case 29:
case 30:
case Break:
cbor_assert(false); /* these conditions can't be reached */
return CborErrorUnexpectedBreak;
}
return CborNoError;
}
/* try to decode up to 16 bits */
if (descriptor < Value8Bit)
return CborNoError;
if (descriptor == Value8Bit)
it->extra = (uint8_t)it->ptr[1];
else if (descriptor == Value16Bit)
it->extra = get16(it->ptr + 1);
else
it->flags |= CborIteratorFlag_IntegerValueTooLarge; /* Value32Bit or Value64Bit */
return CborNoError;
}
static CborError preparse_next_value_nodecrement(CborValue *it) {
if (it->remaining == UINT32_MAX && it->ptr != it->parser->end && *it->ptr == (uint8_t)BreakByte) {
/* end of map or array */
++it->ptr;
it->type = CborInvalidType;
it->remaining = 0;
return CborNoError;
}
return preparse_value(it);
}
static CborError preparse_next_value(CborValue *it) {
if (it->remaining != UINT32_MAX) {
/* don't decrement the item count if the current item is tag: they don't count */
if (it->type != CborTagType && --it->remaining == 0) {
it->type = CborInvalidType;
return CborNoError;
}
}
return preparse_next_value_nodecrement(it);
}
static CborError advance_internal(CborValue *it) {
uint64_t length;
CborError err = _cbor_value_extract_number(&it->ptr, it->parser->end, &length);
cbor_assert(err == CborNoError);
if (it->type == CborByteStringType || it->type == CborTextStringType) {
cbor_assert(length == (size_t)length);
cbor_assert((it->flags & CborIteratorFlag_UnknownLength) == 0);
it->ptr += length;
}
return preparse_next_value(it);
}
/** \internal
*
* Decodes the CBOR integer value when it is larger than the 16 bits available
* in value->extra. This function requires that value->flags have the
* CborIteratorFlag_IntegerValueTooLarge flag set.
*
* This function is also used to extract single- and double-precision floating
* point values (SinglePrecisionFloat == Value32Bit and DoublePrecisionFloat ==
* Value64Bit).
*/
uint64_t _cbor_value_decode_int64_internal(const CborValue *value) {
cbor_assert(value->flags & CborIteratorFlag_IntegerValueTooLarge ||
value->type == CborFloatType || value->type == CborDoubleType);
/* since the additional information can only be Value32Bit or Value64Bit,
* we just need to test for the one bit those two options differ */
cbor_assert((*value->ptr & SmallValueMask) == Value32Bit || (*value->ptr & SmallValueMask) == Value64Bit);
if ((*value->ptr & 1) == (Value32Bit & 1))
return get32(value->ptr + 1);
cbor_assert((*value->ptr & SmallValueMask) == Value64Bit);
return get64(value->ptr + 1);
}
/**
* Initializes the CBOR parser for parsing \a size bytes beginning at \a
* buffer. Parsing will use flags set in \a flags. The iterator to the first
* element is returned in \a it.
*
* The \a parser structure needs to remain valid throughout the decoding
* process. It is not thread-safe to share one CborParser among multiple
* threads iterating at the same time, but the object can be copied so multiple
* threads can iterate.
*/
CborError cbor_parser_init(const uint8_t *buffer, size_t size, uint32_t flags, CborParser *parser, CborValue *it) {
memset(parser, 0, sizeof(*parser));
parser->end = buffer + size;
parser->flags = flags;
it->parser = parser;
it->ptr = buffer;
it->remaining = 1; /* there's one type altogether, usually an array or map */
return preparse_value(it);
}
/**
* \fn bool cbor_value_at_end(const CborValue *it)
*
* Returns true if \a it has reached the end of the iteration, usually when
* advancing after the last item in an array or map.
*
* In the case of the outermost CborValue object, this function returns true
* after decoding a single element. A pointer to the first byte of the
* remaining data (if any) can be obtained with cbor_value_get_next_byte().
*
* \sa cbor_value_advance(), cbor_value_is_valid(), cbor_value_get_next_byte()
*/
/**
* \fn const uint8_t *cbor_value_get_next_byte(const CborValue *it)
*
* Returns a pointer to the next byte that would be decoded if this CborValue
* object were advanced.
*
* This function is useful if cbor_value_at_end() returns true for the
* outermost CborValue: the pointer returned is the first byte of the data
* remaining in the buffer, if any. Code can decide whether to begin decoding a
* new CBOR data stream from this point, or parse some other data appended to
* the same buffer.
*
* This function may be used even after a parsing error. If that occurred,
* then this function returns a pointer to where the parsing error occurred.
* Note that the error recovery is not precise and the pointer may not indicate
* the exact byte containing bad data.
*
* \sa cbor_value_at_end()
*/
/**
* \fn bool cbor_value_is_valid(const CborValue *it)
*
* Returns true if the iterator \a it contains a valid value. Invalid iterators
* happen when iteration reaches the end of a container (see \ref
* cbor_value_at_end()) or when a search function resulted in no matches.
*
* \sa cbor_value_advance(), cbor_value_at_end(), cbor_value_get_type()
*/
/**
* Performs a basic validation of the CBOR stream pointed by \a it and returns
* the error it found. If no error was found, it returns CborNoError and the
* application can iterate over the items with certainty that no other errors
* will appear during parsing.
*
* A basic validation checks for:
* \list
* \li absence of undefined additional information bytes;
* \li well-formedness of all numbers, lengths, and simple values;
* \li string contents match reported sizes;
* \li arrays and maps contain the number of elements they are reported to have;
* \endlist
*
* For further checks, see cbor_value_validate().
*
* This function has the same timing and memory requirements as
* cbor_value_advance().
*
* \sa cbor_value_validate(), cbor_value_advance()
*/
CborError cbor_value_validate_basic(const CborValue *it) {
CborValue value = *it;
return cbor_value_advance(&value);
}
/**
* Advances the CBOR value \a it by one fixed-size position. Fixed-size types
* are: integers, tags, simple types (including boolean, null and undefined
* values) and floating point types.
*
* If the type is not of fixed size, this function has undefined behavior. Code
* must be sure that the current type is one of the fixed-size types before
* calling this function. This function is provided because it can guarantee
* that it runs in constant time (O(1)).
*
* If the caller is not able to determine whether the type is fixed or not, code
* can use the cbor_value_advance() function instead.
*
* \sa cbor_value_at_end(), cbor_value_advance(), cbor_value_enter_container(), cbor_value_leave_container()
*/
CborError cbor_value_advance_fixed(CborValue *it) {
cbor_assert(it->type != CborInvalidType);
cbor_assert(is_fixed_type(it->type));
if (!it->remaining)
return CborErrorAdvancePastEOF;
return advance_internal(it);
}
static CborError advance_recursive(CborValue *it, int nestingLevel) {
CborError err;
CborValue recursed;
if (is_fixed_type(it->type))
return advance_internal(it);
if (!cbor_value_is_container(it)) {
size_t len = SIZE_MAX;
return _cbor_value_copy_string(it, NULL, &len, it);
}
/* map or array */
if (nestingLevel == 0)
return CborErrorNestingTooDeep;
err = cbor_value_enter_container(it, &recursed);
if (err)
return err;
while (!cbor_value_at_end(&recursed)) {
err = advance_recursive(&recursed, nestingLevel - 1);
if (err)
return err;
}
return cbor_value_leave_container(it, &recursed);
}
/**
* Advances the CBOR value \a it by one element, skipping over containers.
* Unlike cbor_value_advance_fixed(), this function can be called on a CBOR
* value of any type. However, if the type is a container (map or array) or a
* string with a chunked payload, this function will not run in constant time
* and will recurse into itself (it will run on O(n) time for the number of
* elements or chunks and will use O(n) memory for the number of nested
* containers).
*
* The number of recursions can be limited at compile time to avoid stack
* exhaustion in constrained systems.
*
* \sa cbor_value_at_end(), cbor_value_advance_fixed(), cbor_value_enter_container(), cbor_value_leave_container()
*/
CborError cbor_value_advance(CborValue *it) {
cbor_assert(it->type != CborInvalidType);
if (!it->remaining)
return CborErrorAdvancePastEOF;
return advance_recursive(it, CBOR_PARSER_MAX_RECURSIONS);
}
/**
* \fn bool cbor_value_is_tag(const CborValue *value)
*
* Returns true if the iterator \a value is valid and points to a CBOR tag.
*
* \sa cbor_value_get_tag(), cbor_value_skip_tag()
*/
/**
* \fn CborError cbor_value_get_tag(const CborValue *value, CborTag *result)
*
* Retrieves the CBOR tag value that \a value points to and stores it in \a
* result. If the iterator \a value does not point to a CBOR tag value, the
* behavior is undefined, so checking with \ref cbor_value_get_type or with
* \ref cbor_value_is_tag is recommended.
*
* \sa cbor_value_get_type(), cbor_value_is_valid(), cbor_value_is_tag()
*/
/**
* Advances the CBOR value \a it until it no longer points to a tag. If \a it is
* already not pointing to a tag, then this function returns it unchanged.
*
* This function does not run in constant time: it will run on O(n) for n being
* the number of tags. It does use constant memory (O(1) memory requirements).
*
* \sa cbor_value_advance_fixed(), cbor_value_advance()
*/
CborError cbor_value_skip_tag(CborValue *it) {
while (cbor_value_is_tag(it)) {
CborError err = cbor_value_advance_fixed(it);
if (err)
return err;
}
return CborNoError;
}
/**
* \fn bool cbor_value_is_container(const CborValue *it)
*
* Returns true if the \a it value is a container and requires recursion in
* order to decode (maps and arrays), false otherwise.
*/
/**
* Creates a CborValue iterator pointing to the first element of the container
* represented by \a it and saves it in \a recursed. The \a it container object
* needs to be kept and passed again to cbor_value_leave_container() in order
* to continue iterating past this container.
*
* The \a it CborValue iterator must point to a container.
*
* \sa cbor_value_is_container(), cbor_value_leave_container(), cbor_value_advance()
*/
CborError cbor_value_enter_container(const CborValue *it, CborValue *recursed) {
cbor_assert(cbor_value_is_container(it));
*recursed = *it;
if (it->flags & CborIteratorFlag_UnknownLength) {
recursed->remaining = UINT32_MAX;
++recursed->ptr;
} else {
uint64_t len;
CborError err = _cbor_value_extract_number(&recursed->ptr, recursed->parser->end, &len);
cbor_assert(err == CborNoError);
recursed->remaining = (uint32_t)len;
if (recursed->remaining != len || len == UINT32_MAX) {
/* back track the pointer to indicate where the error occurred */
recursed->ptr = it->ptr;
return CborErrorDataTooLarge;
}
if (recursed->type == CborMapType) {
/* maps have keys and values, so we need to multiply by 2 */
if (recursed->remaining > UINT32_MAX / 2) {
/* back track the pointer to indicate where the error occurred */
recursed->ptr = it->ptr;
return CborErrorDataTooLarge;
}
recursed->remaining *= 2;
}
if (len == 0) {
/* the case of the empty container */
recursed->type = CborInvalidType;
return CborNoError;
}
}
return preparse_next_value_nodecrement(recursed);
}
/**
* Updates \a it to point to the next element after the container. The \a
* recursed object needs to point to the element obtained either by advancing
* the last element of the container (via cbor_value_advance(),
* cbor_value_advance_fixed(), a nested cbor_value_leave_container(), or the \c
* next pointer from cbor_value_copy_string() or cbor_value_dup_string()).
*
* The \a it and \a recursed parameters must be the exact same as passed to
* cbor_value_enter_container().
*
* \sa cbor_value_enter_container(), cbor_value_at_end()
*/
CborError cbor_value_leave_container(CborValue *it, const CborValue *recursed) {
cbor_assert(cbor_value_is_container(it));
cbor_assert(recursed->type == CborInvalidType);
it->ptr = recursed->ptr;
return preparse_next_value(it);
}
/**
* \fn CborType cbor_value_get_type(const CborValue *value)
*
* Returns the type of the CBOR value that the iterator \a value points to. If
* \a value does not point to a valid value, this function returns \ref
* CborInvalidType.
*
* TinyCBOR also provides functions to test directly if a given CborValue object
* is of a given type, like cbor_value_is_text_string() and cbor_value_is_null().
*
* \sa cbor_value_is_valid()
*/
/**
* \fn bool cbor_value_is_null(const CborValue *value)
*
* Returns true if the iterator \a value is valid and points to a CBOR null type.
*
* \sa cbor_value_is_valid(), cbor_value_is_undefined()
*/
/**
* \fn bool cbor_value_is_undefined(const CborValue *value)
*
* Returns true if the iterator \a value is valid and points to a CBOR undefined type.
*
* \sa cbor_value_is_valid(), cbor_value_is_null()
*/
/**
* \fn bool cbor_value_is_boolean(const CborValue *value)
*
* Returns true if the iterator \a value is valid and points to a CBOR boolean
* type (true or false).
*
* \sa cbor_value_is_valid(), cbor_value_get_boolean()
*/
/**
* \fn CborError cbor_value_get_boolean(const CborValue *value, bool *result)
*
* Retrieves the boolean value that \a value points to and stores it in \a
* result. If the iterator \a value does not point to a boolean value, the
* behavior is undefined, so checking with \ref cbor_value_get_type or with
* \ref cbor_value_is_boolean is recommended.
*
* \sa cbor_value_get_type(), cbor_value_is_valid(), cbor_value_is_boolean()
*/
/**
* \fn bool cbor_value_is_simple_type(const CborValue *value)
*
* Returns true if the iterator \a value is valid and points to a CBOR Simple Type
* type (other than true, false, null and undefined).
*
* \sa cbor_value_is_valid(), cbor_value_get_simple_type()
*/
/**
* \fn CborError cbor_value_get_simple_type(const CborValue *value, uint8_t *result)
*
* Retrieves the CBOR Simple Type value that \a value points to and stores it
* in \a result. If the iterator \a value does not point to a simple_type
* value, the behavior is undefined, so checking with \ref cbor_value_get_type
* or with \ref cbor_value_is_simple_type is recommended.
*
* \sa cbor_value_get_type(), cbor_value_is_valid(), cbor_value_is_simple_type()
*/
/**
* \fn bool cbor_value_is_integer(const CborValue *value)
*
* Returns true if the iterator \a value is valid and points to a CBOR integer
* type.
*
* \sa cbor_value_is_valid(), cbor_value_get_int, cbor_value_get_int64, cbor_value_get_uint64, cbor_value_get_raw_integer
*/
/**
* \fn bool cbor_value_is_unsigned_integer(const CborValue *value)
*
* Returns true if the iterator \a value is valid and points to a CBOR unsigned
* integer type (positive values or zero).
*
* \sa cbor_value_is_valid(), cbor_value_get_uint64()
*/
/**
* \fn bool cbor_value_is_negative_integer(const CborValue *value)
*
* Returns true if the iterator \a value is valid and points to a CBOR negative
* integer type.
*
* \sa cbor_value_is_valid(), cbor_value_get_int, cbor_value_get_int64, cbor_value_get_raw_integer
*/
/**
* \fn CborError cbor_value_get_int(const CborValue *value, int *result)
*
* Retrieves the CBOR integer value that \a value points to and stores it in \a
* result. If the iterator \a value does not point to an integer value, the
* behavior is undefined, so checking with \ref cbor_value_get_type or with
* \ref cbor_value_is_integer is recommended.
*
* Note that this function does not do range-checking: integral values that do
* not fit in a variable of type \c{int} are silently truncated to fit. Use
* cbor_value_get_int_checked() if that is not acceptable.
*
* \sa cbor_value_get_type(), cbor_value_is_valid(), cbor_value_is_integer()
*/
/**
* \fn CborError cbor_value_get_int64(const CborValue *value, int64_t *result)
*
* Retrieves the CBOR integer value that \a value points to and stores it in \a
* result. If the iterator \a value does not point to an integer value, the
* behavior is undefined, so checking with \ref cbor_value_get_type or with
* \ref cbor_value_is_integer is recommended.
*
* Note that this function does not do range-checking: integral values that do
* not fit in a variable of type \c{int64_t} are silently truncated to fit. Use
* cbor_value_get_int64_checked() that is not acceptable.
*
* \sa cbor_value_get_type(), cbor_value_is_valid(), cbor_value_is_integer()
*/
/**
* \fn CborError cbor_value_get_uint64(const CborValue *value, uint64_t *result)
*
* Retrieves the CBOR integer value that \a value points to and stores it in \a
* result. If the iterator \a value does not point to an unsigned integer
* value, the behavior is undefined, so checking with \ref cbor_value_get_type
* or with \ref cbor_value_is_unsigned_integer is recommended.
*
* \sa cbor_value_get_type(), cbor_value_is_valid(), cbor_value_is_unsigned_integer()
*/
/**
* \fn CborError cbor_value_get_raw_integer(const CborValue *value, uint64_t *result)
*
* Retrieves the CBOR integer value that \a value points to and stores it in \a
* result. If the iterator \a value does not point to an integer value, the
* behavior is undefined, so checking with \ref cbor_value_get_type or with
* \ref cbor_value_is_integer is recommended.
*
* This function is provided because CBOR negative integers can assume values
* that cannot be represented with normal 64-bit integer variables.
*
* If the integer is unsigned (that is, if cbor_value_is_unsigned_integer()
* returns true), then \a result will contain the actual value. If the integer
* is negative, then \a result will contain the absolute value of that integer,
* minus one. That is, \c {actual = -result - 1}. On architectures using two's
* complement for representation of negative integers, it is equivalent to say
* that \a result will contain the bitwise negation of the actual value.
*
* \sa cbor_value_get_type(), cbor_value_is_valid(), cbor_value_is_integer()
*/
/**
* Retrieves the CBOR integer value that \a value points to and stores it in \a
* result. If the iterator \a value does not point to an integer value, the
* behavior is undefined, so checking with \ref cbor_value_get_type or with
* \ref cbor_value_is_integer is recommended.
*
* Unlike \ref cbor_value_get_int64(), this function performs a check to see if the
* stored integer fits in \a result without data loss. If the number is outside
* the valid range for the data type, this function returns the recoverable
* error CborErrorDataTooLarge. In that case, use either
* cbor_value_get_uint64() (if the number is positive) or
* cbor_value_get_raw_integer().
*
* \sa cbor_value_get_type(), cbor_value_is_valid(), cbor_value_is_integer(), cbor_value_get_int64()
*/
CborError cbor_value_get_int64_checked(const CborValue *value, int64_t *result) {
uint64_t v;
cbor_assert(cbor_value_is_integer(value));
v = _cbor_value_extract_int64_helper(value);
/* Check before converting, as the standard says (C11 6.3.1.3 paragraph 3):
* "[if] the new type is signed and the value cannot be represented in it; either the
* result is implementation-defined or an implementation-defined signal is raised."
*
* The range for int64_t is -2^63 to 2^63-1 (int64_t is required to be
* two's complement, C11 7.20.1.1 paragraph 3), which in CBOR is
* represented the same way, differing only on the "sign bit" (the major
* type).
*/
if (unlikely(v > (uint64_t)INT64_MAX))
return CborErrorDataTooLarge;
*result = v;
if (value->flags & CborIteratorFlag_NegativeInteger)
*result = -*result - 1;
return CborNoError;
}
/**
* Retrieves the CBOR integer value that \a value points to and stores it in \a
* result. If the iterator \a value does not point to an integer value, the
* behavior is undefined, so checking with \ref cbor_value_get_type or with
* \ref cbor_value_is_integer is recommended.
*
* Unlike \ref cbor_value_get_int(), this function performs a check to see if the
* stored integer fits in \a result without data loss. If the number is outside
* the valid range for the data type, this function returns the recoverable
* error CborErrorDataTooLarge. In that case, use one of the other integer
* functions to obtain the value.
*
* \sa cbor_value_get_type(), cbor_value_is_valid(), cbor_value_is_integer(), cbor_value_get_int64(),
* cbor_value_get_uint64(), cbor_value_get_int64_checked(), cbor_value_get_raw_integer()
*/
CborError cbor_value_get_int_checked(const CborValue *value, int *result) {
uint64_t v;
cbor_assert(cbor_value_is_integer(value));
v = _cbor_value_extract_int64_helper(value);
/* Check before converting, as the standard says (C11 6.3.1.3 paragraph 3):
* "[if] the new type is signed and the value cannot be represented in it; either the
* result is implementation-defined or an implementation-defined signal is raised."
*
* But we can convert from signed to unsigned without fault (paragraph 2).
*
* The range for int is implementation-defined and int is not guaranteed to use
* two's complement representation (although int32_t is).
*/
if (value->flags & CborIteratorFlag_NegativeInteger) {
if (unlikely(v > (unsigned) - (INT_MIN + 1)))
return CborErrorDataTooLarge;
*result = (int)v;
*result = -*result - 1;
} else {
if (unlikely(v > (uint64_t)INT_MAX))
return CborErrorDataTooLarge;
*result = (int)v;
}
return CborNoError;
}
/**
* \fn bool cbor_value_is_length_known(const CborValue *value)
*
* Returns true if the length of this type is known without calculation. That
* is, if the length of this CBOR string, map or array is encoded in the data
* stream, this function returns true. If the length is not encoded, it returns
* false.
*
* If the length is known, code can call cbor_value_get_string_length(),
* cbor_value_get_array_length() or cbor_value_get_map_length() to obtain the
* length. If the length is not known but is necessary, code can use the
* cbor_value_calculate_string_length() function (no equivalent function is
* provided for maps and arrays).
*/
/**
* \fn bool cbor_value_is_text_string(const CborValue *value)
*
* Returns true if the iterator \a value is valid and points to a CBOR text
* string. CBOR text strings are UTF-8 encoded and usually contain
* human-readable text.
*
* \sa cbor_value_is_valid(), cbor_value_get_string_length(), cbor_value_calculate_string_length(),
* cbor_value_copy_text_string(), cbor_value_dup_text_string()
*/
/**
* \fn bool cbor_value_is_byte_string(const CborValue *value)
*
* Returns true if the iterator \a value is valid and points to a CBOR text
* string. CBOR byte strings are binary data with no specified encoding or
* format.
*
* \sa cbor_value_is_valid(), cbor_value_get_string_length(), cbor_value_calculate_string_length(),
* cbor_value_copy_byte_string(), cbor_value_dup_byte_string()
*/
/**
* \fn CborError cbor_value_get_string_length(const CborValue *value, size_t *length)
*
* Extracts the length of the byte or text string that \a value points to and
* stores it in \a result. If the iterator \a value does not point to a text
* string or a byte string, the behaviour is undefined, so checking with \ref
* cbor_value_get_type, with \ref cbor_value_is_text_string or \ref
* cbor_value_is_byte_string is recommended.
*
* If the length of this string is not encoded in the CBOR data stream, this
* function will return the recoverable error CborErrorUnknownLength. You may
* also check whether that is the case by using cbor_value_is_length_known().
*
* If the length of the string is required but the length was not encoded, use
* cbor_value_calculate_string_length(), but note that that function does not
* run in constant time.
*
* \note On 32-bit platforms, this function will return error condition of \ref
* CborErrorDataTooLarge if the stream indicates a length that is too big to
* fit in 32-bit.
*
* \sa cbor_value_is_valid(), cbor_value_is_length_known(), cbor_value_calculate_string_length()
*/
/**
* Calculates the length of the byte or text string that \a value points to and
* stores it in \a len. If the iterator \a value does not point to a text
* string or a byte string, the behaviour is undefined, so checking with \ref
* cbor_value_get_type, with \ref cbor_value_is_text_string or \ref
* cbor_value_is_byte_string is recommended.
*
* This function is different from cbor_value_get_string_length() in that it
* calculates the length even for strings sent in chunks. For that reason, this
* function may not run in constant time (it will run in O(n) time on the
* number of chunks). It does use constant memory (O(1)).
*
* \note On 32-bit platforms, this function will return error condition of \ref
* CborErrorDataTooLarge if the stream indicates a length that is too big to
* fit in 32-bit.
*
* \sa cbor_value_get_string_length(), cbor_value_copy_text_string(), cbor_value_copy_byte_string(), cbor_value_is_length_known()
*/
CborError cbor_value_calculate_string_length(const CborValue *value, size_t *len) {
*len = SIZE_MAX;
return _cbor_value_copy_string(value, NULL, len, NULL);
}
static inline void prepare_string_iteration(CborValue *it) {
if (!cbor_value_is_length_known(it)) {
/* chunked string: we're before the first chunk;
* advance to the first chunk */
++it->ptr;
it->flags |= CborIteratorFlag_IteratingStringChunks;
}
}
CborError CBOR_INTERNAL_API_CC _cbor_value_prepare_string_iteration(CborValue *it) {
cbor_assert((it->flags & CborIteratorFlag_IteratingStringChunks) == 0);
prepare_string_iteration(it);
/* are we at the end? */
if (it->ptr == it->parser->end)
return CborErrorUnexpectedEOF;
return CborNoError;
}
static CborError get_string_chunk(CborValue *it, const void **bufferptr, size_t *len) {
CborError err;
/* Possible states:
* length known | iterating | meaning
* no | no | before the first chunk of a chunked string
* yes | no | at a non-chunked string
* no | yes | second or later chunk
* yes | yes | after a non-chunked string
*/
if (it->flags & CborIteratorFlag_IteratingStringChunks) {
/* already iterating */
if (cbor_value_is_length_known(it)) {
/* if the length was known, it wasn't chunked, so finish iteration */
goto last_chunk;
}
} else {
prepare_string_iteration(it);
}
/* are we at the end? */
if (it->ptr == it->parser->end)
return CborErrorUnexpectedEOF;
if (*it->ptr == BreakByte) {
/* last chunk */
++it->ptr;
last_chunk:
*bufferptr = NULL;
*len = 0;
return preparse_next_value(it);
} else if ((uint8_t)(*it->ptr & MajorTypeMask) == it->type) {
err = extract_length(it->parser, &it->ptr, len);
if (err)
return err;
if (*len > (size_t)(it->parser->end - it->ptr))
return CborErrorUnexpectedEOF;
*bufferptr = it->ptr;
it->ptr += *len;
} else {
return CborErrorIllegalType;
}
it->flags |= CborIteratorFlag_IteratingStringChunks;
return CborNoError;
}
CborError CBOR_INTERNAL_API_CC
_cbor_value_get_string_chunk(const CborValue *value, const void **bufferptr,
size_t *len, CborValue *next) {
CborValue tmp;
if (!next)
next = &tmp;
*next = *value;
return get_string_chunk(next, bufferptr, len);
}
/* We return uintptr_t so that we can pass memcpy directly as the iteration
* function. The choice is to optimize for memcpy, which is used in the base
* parser API (cbor_value_copy_string), while memcmp is used in convenience API
* only. */
typedef uintptr_t (*IterateFunction)(char *, const uint8_t *, size_t);
static uintptr_t iterate_noop(char *dest, const uint8_t *src, size_t len) {
(void)dest;
(void)src;
(void)len;
return true;
}
static uintptr_t iterate_memcmp(char *s1, const uint8_t *s2, size_t len) {
return memcmp(s1, (const char *)s2, len) == 0;
}
static uintptr_t iterate_memcpy(char *dest, const uint8_t *src, size_t len) {
return (uintptr_t)memcpy(dest, src, len);
}
static CborError iterate_string_chunks(const CborValue *value, char *buffer, size_t *buflen,
bool *result, CborValue *next, IterateFunction func) {
CborError err;
CborValue tmp;
size_t total = 0;
const void *ptr;
cbor_assert(cbor_value_is_byte_string(value) || cbor_value_is_text_string(value));
if (!next)
next = &tmp;
*next = *value;
*result = true;
while (1) {
size_t newTotal;
size_t chunkLen;
err = get_string_chunk(next, &ptr, &chunkLen);
if (err)
return err;
if (!ptr)
break;
if (unlikely(add_check_overflow(total, chunkLen, &newTotal)))
return CborErrorDataTooLarge;
if (*result && *buflen >= newTotal)
*result = !!func(buffer + total, (const uint8_t *)ptr, chunkLen);
else
*result = false;
total = newTotal;
}
/* is there enough room for the ending NUL byte? */
if (*result && *buflen > total) {
uint8_t nul[] = { 0 };
*result = !!func(buffer + total, nul, 1);
}
*buflen = total;
return CborNoError;
}
/**
* \fn CborError cbor_value_copy_text_string(const CborValue *value, char *buffer, size_t *buflen, CborValue *next)
*
* Copies the string pointed to by \a value into the buffer provided at \a buffer
* of \a buflen bytes. If \a buffer is a NULL pointer, this function will not
* copy anything and will only update the \a next value.
*
* If the iterator \a value does not point to a text string, the behaviour is
* undefined, so checking with \ref cbor_value_get_type or \ref
* cbor_value_is_text_string is recommended.
*
* If the provided buffer length was too small, this function returns an error
* condition of \ref CborErrorOutOfMemory. If you need to calculate the length
* of the string in order to preallocate a buffer, use
* cbor_value_calculate_string_length().
*
* On success, this function sets the number of bytes copied to \c{*buflen}. If
* the buffer is large enough, this function will insert a null byte after the
* last copied byte, to facilitate manipulation of text strings. That byte is
* not included in the returned value of \c{*buflen}. If there was no space for
* the terminating null, no error is returned, so callers must check the value
* of *buflen after the call, before relying on the '\0'; if it has not been
* changed by the call, there is no '\0'-termination on the buffer's contents.
*
* The \a next pointer, if not null, will be updated to point to the next item
* after this string. If \a value points to the last item, then \a next will be
* invalid.
*
* This function may not run in constant time (it will run in O(n) time on the
* number of chunks). It requires constant memory (O(1)).
*
* \note This function does not perform UTF-8 validation on the incoming text
* string.
*
* \sa cbor_value_get_text_string_chunk() cbor_value_dup_text_string(), cbor_value_copy_byte_string(), cbor_value_get_string_length(), cbor_value_calculate_string_length()
*/
/**
* \fn CborError cbor_value_copy_byte_string(const CborValue *value, uint8_t *buffer, size_t *buflen, CborValue *next)
*
* Copies the string pointed by \a value into the buffer provided at \a buffer
* of \a buflen bytes. If \a buffer is a NULL pointer, this function will not
* copy anything and will only update the \a next value.
*
* If the iterator \a value does not point to a byte string, the behaviour is
* undefined, so checking with \ref cbor_value_get_type or \ref
* cbor_value_is_byte_string is recommended.
*
* If the provided buffer length was too small, this function returns an error
* condition of \ref CborErrorOutOfMemory. If you need to calculate the length
* of the string in order to preallocate a buffer, use
* cbor_value_calculate_string_length().
*
* On success, this function sets the number of bytes copied to \c{*buflen}. If
* the buffer is large enough, this function will insert a null byte after the
* last copied byte, to facilitate manipulation of null-terminated strings.
* That byte is not included in the returned value of \c{*buflen}.
*
* The \a next pointer, if not null, will be updated to point to the next item
* after this string. If \a value points to the last item, then \a next will be
* invalid.
*
* This function may not run in constant time (it will run in O(n) time on the
* number of chunks). It requires constant memory (O(1)).
*
* \sa cbor_value_get_byte_string_chunk(), cbor_value_dup_text_string(), cbor_value_copy_text_string(), cbor_value_get_string_length(), cbor_value_calculate_string_length()
*/
CborError _cbor_value_copy_string(const CborValue *value, void *buffer,
size_t *buflen, CborValue *next) {
bool copied_all;
CborError err = iterate_string_chunks(value, (char *)buffer, buflen, &copied_all, next,
buffer ? iterate_memcpy : iterate_noop);
return err ? err :
copied_all ? CborNoError : CborErrorOutOfMemory;
}
/**
* Compares the entry \a value with the string \a string and stores the result
* in \a result. If the value is different from \a string \a result will
* contain \c false.
*
* The entry at \a value may be a tagged string. If \a value is not a string or
* a tagged string, the comparison result will be false.
*
* CBOR requires text strings to be encoded in UTF-8, but this function does
* not validate either the strings in the stream or the string \a string to be
* matched. Moreover, comparison is done on strict codepoint comparison,
* without any Unicode normalization.
*
* This function may not run in constant time (it will run in O(n) time on the
* number of chunks). It requires constant memory (O(1)).
*
* \sa cbor_value_skip_tag(), cbor_value_copy_text_string()
*/
CborError cbor_value_text_string_equals(const CborValue *value, const char *string, bool *result) {
size_t len;
CborValue copy = *value;
CborError err = cbor_value_skip_tag(&copy);
if (err)
return err;
if (!cbor_value_is_text_string(&copy)) {
*result = false;
return CborNoError;
}
len = strlen(string);
return iterate_string_chunks(&copy, CONST_CAST(char *, string), &len, result, NULL, iterate_memcmp);
}
/**
* \fn bool cbor_value_is_array(const CborValue *value)
*
* Returns true if the iterator \a value is valid and points to a CBOR array.
*
* \sa cbor_value_is_valid(), cbor_value_is_map()
*/
/**
* \fn CborError cbor_value_get_array_length(const CborValue *value, size_t *length)
*
* Extracts the length of the CBOR array that \a value points to and stores it
* in \a result. If the iterator \a value does not point to a CBOR array, the
* behaviour is undefined, so checking with \ref cbor_value_get_type or \ref
* cbor_value_is_array is recommended.
*
* If the length of this array is not encoded in the CBOR data stream, this
* function will return the recoverable error CborErrorUnknownLength. You may
* also check whether that is the case by using cbor_value_is_length_known().
*
* \note On 32-bit platforms, this function will return error condition of \ref
* CborErrorDataTooLarge if the stream indicates a length that is too big to
* fit in 32-bit.
*
* \sa cbor_value_is_valid(), cbor_value_is_length_known()
*/
/**
* \fn bool cbor_value_is_map(const CborValue *value)
*
* Returns true if the iterator \a value is valid and points to a CBOR map.
*
* \sa cbor_value_is_valid(), cbor_value_is_array()
*/
/**
* \fn CborError cbor_value_get_map_length(const CborValue *value, size_t *length)
*
* Extracts the length of the CBOR map that \a value points to and stores it in
* \a result. If the iterator \a value does not point to a CBOR map, the
* behaviour is undefined, so checking with \ref cbor_value_get_type or \ref
* cbor_value_is_map is recommended.
*
* If the length of this map is not encoded in the CBOR data stream, this
* function will return the recoverable error CborErrorUnknownLength. You may
* also check whether that is the case by using cbor_value_is_length_known().
*
* \note On 32-bit platforms, this function will return error condition of \ref
* CborErrorDataTooLarge if the stream indicates a length that is too big to
* fit in 32-bit.
*
* \sa cbor_value_is_valid(), cbor_value_is_length_known()
*/
/**
* Attempts to find the value in map \a map that corresponds to the text string
* entry \a string. If the iterator \a value does not point to a CBOR map, the
* behaviour is undefined, so checking with \ref cbor_value_get_type or \ref
* cbor_value_is_map is recommended.
*
* If the item is found, it is stored in \a result. If no item is found
* matching the key, then \a result will contain an element of type \ref
* CborInvalidType. Matching is performed using
* cbor_value_text_string_equals(), so tagged strings will also match.
*
* This function has a time complexity of O(n) where n is the number of
* elements in the map to be searched. In addition, this function is has O(n)
* memory requirement based on the number of nested containers (maps or arrays)
* found as elements of this map.
*
* \sa cbor_value_is_valid(), cbor_value_text_string_equals(), cbor_value_advance()
*/
CborError cbor_value_map_find_value(const CborValue *map, const char *string, CborValue *element) {
CborError err;
size_t len = strlen(string);
cbor_assert(cbor_value_is_map(map));
err = cbor_value_enter_container(map, element);
if (err)
goto error;
while (!cbor_value_at_end(element)) {
/* find the non-tag so we can compare */
err = cbor_value_skip_tag(element);
if (err)
goto error;
if (cbor_value_is_text_string(element)) {
bool equals;
size_t dummyLen = len;
err = iterate_string_chunks(element, CONST_CAST(char *, string), &dummyLen,
&equals, element, iterate_memcmp);
if (err)
goto error;
if (equals)
return preparse_value(element);
} else {
/* skip this key */
err = cbor_value_advance(element);
if (err)
goto error;
}
/* skip this value */
err = cbor_value_skip_tag(element);
if (err)
goto error;
err = cbor_value_advance(element);
if (err)
goto error;
}
/* not found */
element->type = CborInvalidType;
return CborNoError;
error:
element->type = CborInvalidType;
return err;
}
/**
* \fn bool cbor_value_is_float(const CborValue *value)
*
* Returns true if the iterator \a value is valid and points to a CBOR
* single-precision floating point (32-bit).
*
* \sa cbor_value_is_valid(), cbor_value_is_double(), cbor_value_is_half_float()
*/
/**
* \fn CborError cbor_value_get_float(const CborValue *value, float *result)
*
* Retrieves the CBOR single-precision floating point (32-bit) value that \a
* value points to and stores it in \a result. If the iterator \a value does
* not point to a single-precision floating point value, the behavior is
* undefined, so checking with \ref cbor_value_get_type or with \ref
* cbor_value_is_float is recommended.
*
* \sa cbor_value_get_type(), cbor_value_is_valid(), cbor_value_is_float(), cbor_value_get_double()
*/
/**
* \fn bool cbor_value_is_double(const CborValue *value)
*
* Returns true if the iterator \a value is valid and points to a CBOR
* double-precision floating point (64-bit).
*
* \sa cbor_value_is_valid(), cbor_value_is_float(), cbor_value_is_half_float()
*/
/**
* \fn CborError cbor_value_get_double(const CborValue *value, float *result)
*
* Retrieves the CBOR double-precision floating point (64-bit) value that \a
* value points to and stores it in \a result. If the iterator \a value does
* not point to a double-precision floating point value, the behavior is
* undefined, so checking with \ref cbor_value_get_type or with \ref
* cbor_value_is_double is recommended.
*
* \sa cbor_value_get_type(), cbor_value_is_valid(), cbor_value_is_double(), cbor_value_get_float()
*/
/**
* \fn bool cbor_value_is_half_float(const CborValue *value)
*
* Returns true if the iterator \a value is valid and points to a CBOR
* single-precision floating point (16-bit).
*
* \sa cbor_value_is_valid(), cbor_value_is_double(), cbor_value_is_float()
*/
/**
* Retrieves the CBOR half-precision floating point (16-bit) value that \a
* value points to and stores it in \a result. If the iterator \a value does
* not point to a half-precision floating point value, the behavior is
* undefined, so checking with \ref cbor_value_get_type or with \ref
* cbor_value_is_half_float is recommended.
*
* Note: since the C language does not have a standard type for half-precision
* floating point, this function takes a \c{void *} as a parameter for the
* storage area, which must be at least 16 bits wide.
*
* \sa cbor_value_get_type(), cbor_value_is_valid(), cbor_value_is_half_float(), cbor_value_get_float()
*/
CborError cbor_value_get_half_float(const CborValue *value, void *result) {
uint16_t v;
cbor_assert(cbor_value_is_half_float(value));
/* size has been computed already */
v = get16(value->ptr + 1);
memcpy(result, &v, sizeof(v));
return CborNoError;
}
/** @} */
Reference in a new issue View git blame Copy permalink