Crate der_parser [−] [src]
DER Parser
A DER (X.690) parser, implemented with the nom parser combinator framework.
The code is available on Github and is part of the Rusticata project.
DER parser design
There are two different approaches for parsing DER objects: reading the objects recursively as long as the tags are known, or specifying a description of the expected objects (generally from the ASN.1 description).
The first parsing method can be done using the parse_der
method.
However, it cannot fully parse all objects, especially those containing IMPLICIT, OPTIONAL, or
DEFINED BY items.
use der_parser::parse_der; let bytes = [ 0x30, 0x0a, 0x02, 0x03, 0x01, 0x00, 0x01, 0x02, 0x03, 0x01, 0x00, 0x00, ]; let parsed = parse_der(&bytes);
To specify the expected objects, the parsing methods must be specified for every object recursively.
For example, to read a sequence containing two integers:
use der_parser::*; use nom::{IResult,Err,ErrorKind}; fn localparse_seq(i:&[u8]) -> IResult<&[u8],DerObject> { parse_der_sequence_defined!(i, parse_der_integer, parse_der_integer ) } let bytes = [ 0x30, 0x0a, 0x02, 0x03, 0x01, 0x00, 0x01, 0x02, 0x03, 0x01, 0x00, 0x00, ]; let parsed = localparse_seq(&bytes);
All functions return an IResult
object from nom
: the parsed
DerObject
, an Incomplete
value, or an error.
Notes
- The DER constraints are not enforced or verified. Because of that, this parser is mostly compatible with BER.
- DER integers can be of any size, so it is not possible to store them as simple integers (they
are stored as raw bytes). To get a simple value, use
DerObject::as_u32
(knowning that this method will return an error if the integer is too large), or use thebigint
feature of this crate and useDerObject::as_bigint
.
References
Modules
oid |
Object ID (OID) representation |
Macros
parse_der_optional |
Parse an optional DER element |
parse_der_sequence_defined |
Parse a sequence of DER elements (folding version) |
parse_der_sequence_defined_m |
Parse a sequence of DER elements (macro version) |
parse_der_sequence_of |
Parse a sequence of identical DER elements |
parse_der_set_defined |
Parse a set of DER elements (folding version) |
parse_der_set_defined_m |
Parse a set of DER elements (macro version) |
parse_der_set_of |
Parse a set of identical DER elements |
parse_der_struct |
Parse a constructed DER element |
Structs
DerObject |
Representation of a DER-encoded (X.690) object |
DerObjectHeader | |
DerObjectIntoIterator | |
DerObjectRefIterator | |
PrettyDer |
Enums
DerError | |
DerObjectContent | |
DerTag |
Defined in X.680 section 8.4 |
PrettyPrinterFlag |
Constants
DER_CLASS_ERROR |
Unexpected DER class |
DER_INVALID_LENGTH |
Invalid length for DER object |
DER_OBJ_TOOSHORT |
Items contained in a structured object do not fill the entire container object |
DER_STRUCT_ERROR |
Unexpected DER structured flag |
DER_TAG_ERROR |
Unexpected DER tag |
DER_TAG_UNKNOWN |
Unknown or unsupported DER tag |
Functions
der_read_element_content | |
der_read_element_content_as |
Parse the next bytes as the content of a DER object. |
der_read_element_header | |
parse_der | |
parse_der_bitstring | |
parse_der_bmpstring | |
parse_der_bool |
Read a boolean value |
parse_der_enum | |
parse_der_explicit | |
parse_der_explicit_failed | |
parse_der_generalizedtime | |
parse_der_generalstring | |
parse_der_ia5string | |
parse_der_implicit |
call der content parsing function |
parse_der_integer | |
parse_der_null | |
parse_der_numericstring | |
parse_der_octetstring | |
parse_der_oid | |
parse_der_printablestring | |
parse_der_sequence |
Parse a sequence of DER elements |
parse_der_set |
Parse a set of DER elements |
parse_der_t61string | |
parse_der_utctime | |
parse_der_utf8string |