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use crate::ber::*;
use crate::der::DerObject;
use crate::error::*;
use nom::number::streaming::be_u8;
use nom::*;
use rusticata_macros::custom_check;
use std::convert::TryFrom;
use crate::ber::MAX_RECURSION;
/// Parse DER object recursively
///
/// Return a tuple containing the remaining (unparsed) bytes and the DER Object, or an error.
///
/// *Note: this is the same as calling `parse_der_recursive` with `MAX_RECURSION`.
///
/// ### Example
///
/// ```
/// use der_parser::ber::BerTag;
/// use der_parser::der::parse_der;
///
/// let bytes = &[0x02, 0x03, 0x01, 0x00, 0x01];
/// let (_, obj) = parse_der(bytes).expect("parsing failed");
///
/// assert_eq!(obj.header.tag, BerTag::Integer);
/// ```
#[inline]
pub fn parse_der(i: &[u8]) -> DerResult {
parse_der_recursive(i, MAX_RECURSION)
}
/// Parse DER object recursively, specifying the maximum recursion depth
///
/// Return a tuple containing the remaining (unparsed) bytes and the DER Object, or an error.
///
/// ### Example
///
/// ```
/// use der_parser::ber::BerTag;
/// use der_parser::der::parse_der_recursive;
///
/// let bytes = &[0x02, 0x03, 0x01, 0x00, 0x01];
/// let (_, obj) = parse_der_recursive(bytes, 1).expect("parsing failed");
///
/// assert_eq!(obj.header.tag, BerTag::Integer);
/// ```
pub fn parse_der_recursive(i: &[u8], max_depth: usize) -> DerResult {
do_parse! {
i,
hdr: der_read_element_header >>
// XXX safety check: length cannot be more than 2^32 bytes
custom_check!(hdr.len > u64::from(::std::u32::MAX), BerError::InvalidLength) >>
content: call!(der_read_element_content_recursive, hdr, max_depth) >>
( content )
}
}
#[doc(hidden)]
#[macro_export]
macro_rules! der_constraint_fail_if(
($slice:expr, $cond:expr) => (
{
if $cond {
return Err(::nom::Err::Error(BerError::DerConstraintFailed));
}
}
);
);
/// Parse a DER object, expecting a value with specificed tag
pub fn parse_der_with_tag(i: &[u8], tag: BerTag) -> DerResult {
do_parse! {
i,
hdr: der_read_element_header >>
custom_check!(hdr.tag != tag, BerError::InvalidTag) >>
o: call!(der_read_element_content_as, hdr.tag, hdr.len as usize, hdr.is_constructed(), MAX_RECURSION) >>
( BerObject::from_header_and_content(hdr, o) )
}
}
/// Read end of content marker
#[inline]
pub fn parse_der_endofcontent(i: &[u8]) -> DerResult {
parse_der_with_tag(i, BerTag::EndOfContent)
}
/// Read a boolean value
///
/// The encoding of a boolean value shall be primitive. The contents octets shall consist of a
/// single octet.
///
/// If the boolean value is FALSE, the octet shall be zero.
/// If the boolean value is TRUE, the octet shall be one byte, and have all bits set to one (0xff).
#[inline]
pub fn parse_der_bool(i: &[u8]) -> DerResult {
parse_der_with_tag(i, BerTag::Boolean)
}
/// Read an integer value
///
/// The encoding of a boolean value shall be primitive. The contents octets shall consist of one or
/// more octets.
///
/// To access the content, use the [`as_u64`](struct.BerObject.html#method.as_u64),
/// [`as_u32`](struct.BerObject.html#method.as_u32),
/// [`as_biguint`](struct.BerObject.html#method.as_biguint) or
/// [`as_bigint`](struct.BerObject.html#method.as_bigint) methods.
/// Remember that a BER integer has unlimited size, so these methods return `Result` or `Option`
/// objects.
///
/// # Examples
///
/// ```rust
/// # #[macro_use] extern crate der_parser;
/// # extern crate nom;
/// # use der_parser::der::{parse_der_integer, DerObject};
/// # use der_parser::ber::BerObjectContent;
/// let empty = &b""[..];
/// let bytes = [0x02, 0x03, 0x01, 0x00, 0x01];
/// let expected = DerObject::from_obj(BerObjectContent::Integer(b"\x01\x00\x01"));
/// assert_eq!(
/// parse_der_integer(&bytes),
/// Ok((empty, expected))
/// );
/// ```
#[inline]
pub fn parse_der_integer(i: &[u8]) -> DerResult {
parse_der_with_tag(i, BerTag::Integer)
}
/// Read an bitstring value
pub fn parse_der_bitstring(i: &[u8]) -> DerResult {
do_parse! {
i,
hdr: der_read_element_header >>
custom_check!(hdr.tag != BerTag::BitString, BerError::InvalidTag) >>
custom_check!(hdr.is_constructed(), BerError::DerConstraintFailed) >>
b: call!(der_read_content_bitstring, hdr.len as usize) >>
( DerObject::from_header_and_content(hdr, b) )
}
}
/// Read an octetstring value
#[inline]
pub fn parse_der_octetstring(i: &[u8]) -> DerResult {
parse_der_with_tag(i, BerTag::OctetString)
}
/// Read a null value
#[inline]
pub fn parse_der_null(i: &[u8]) -> DerResult {
parse_der_with_tag(i, BerTag::Null)
}
/// Read an object identifier value
#[inline]
pub fn parse_der_oid(i: &[u8]) -> DerResult {
parse_der_with_tag(i, BerTag::Oid)
}
/// Read an enumerated value
#[inline]
pub fn parse_der_enum(i: &[u8]) -> DerResult {
parse_der_with_tag(i, BerTag::Enumerated)
}
/// Read a UTF-8 string value. The encoding is checked.
#[inline]
pub fn parse_der_utf8string(i: &[u8]) -> DerResult {
parse_der_with_tag(i, BerTag::Utf8String)
}
/// Read a relative object identifier value
#[inline]
pub fn parse_der_relative_oid(i: &[u8]) -> DerResult {
parse_der_with_tag(i, BerTag::RelativeOid)
}
/// Parse a sequence of DER elements
///
/// Read a sequence of DER objects, without any constraint on the types.
/// Sequence is parsed recursively, so if structured elements are found, they are parsed using the
/// same function.
///
/// To read a specific sequence of objects (giving the expected types), use the
/// [`parse_ber_sequence_defined`](macro.parse_ber_sequence_defined.html) macro.
#[inline]
pub fn parse_der_sequence(i: &[u8]) -> DerResult {
parse_der_with_tag(i, BerTag::Sequence)
}
/// Parse a set of DER elements
///
/// Read a set of DER objects, without any constraint on the types.
/// Set is parsed recursively, so if structured elements are found, they are parsed using the
/// same function.
///
/// To read a specific set of objects (giving the expected types), use the
/// [`parse_ber_set_defined`](macro.parse_ber_set_defined.html) macro.
#[inline]
pub fn parse_der_set(i: &[u8]) -> DerResult {
parse_der_with_tag(i, BerTag::Set)
}
/// Read a numeric string value. The content is verified to
/// contain only digits and spaces.
#[inline]
pub fn parse_der_numericstring(i: &[u8]) -> DerResult {
parse_der_with_tag(i, BerTag::NumericString)
}
/// Read a printable string value. The content is verified to
/// contain only the allowed characters.
#[inline]
pub fn parse_der_printablestring(i: &[u8]) -> DerResult {
parse_der_with_tag(i, BerTag::PrintableString)
}
/// Read a T61 string value
#[inline]
pub fn parse_der_t61string(i: &[u8]) -> DerResult {
parse_der_with_tag(i, BerTag::T61String)
}
/// Read an IA5 string value. The content is verified to be ASCII.
#[inline]
pub fn parse_der_ia5string(i: &[u8]) -> DerResult {
parse_der_with_tag(i, BerTag::Ia5String)
}
/// Read an UTC time value
#[inline]
pub fn parse_der_utctime(i: &[u8]) -> DerResult {
parse_der_with_tag(i, BerTag::UtcTime)
}
/// Read a Generalized time value
#[inline]
pub fn parse_der_generalizedtime(i: &[u8]) -> DerResult {
parse_der_with_tag(i, BerTag::GeneralizedTime)
}
/// Read a GeneralString value
#[inline]
pub fn parse_der_generalstring(i: &[u8]) -> DerResult {
parse_der_with_tag(i, BerTag::GeneralString)
}
/// Read a BmpString value
#[inline]
pub fn parse_der_bmpstring(i: &[u8]) -> DerResult {
parse_der_with_tag(i, BerTag::BmpString)
}
/// Parse an optional tagged object, applying function to get content
///
/// This function returns a `DerObject`, trying to read content as generic DER objects.
/// If parsing failed, return an optional object containing `None`.
///
/// This function will never fail: if parsing content failed, the BER value `Optional(None)` is
/// returned.
#[inline]
pub fn parse_der_explicit_optional<F>(i: &[u8], tag: BerTag, f: F) -> DerResult
where
F: Fn(&[u8]) -> DerResult,
{
parse_ber_explicit_optional(i, tag, f)
}
/// Parse an optional tagged object, applying function to get content
///
/// This function is deprecated, use
/// [parse_der_explicit_optional](fn.parse_der_explicit_optional.html) instead.
#[deprecated(
since = "4.1.0",
note = "Please use `parse_der_explicit_optional` instead"
)]
#[inline]
pub fn parse_der_explicit<F>(i: &[u8], tag: BerTag, f: F) -> BerResult
where
F: Fn(&[u8]) -> BerResult,
{
parse_der_explicit_optional(i, tag, f)
}
#[inline]
pub fn parse_der_implicit<F>(i: &[u8], tag: BerTag, f: F) -> DerResult
where
F: Fn(&[u8], BerTag, usize) -> BerResult<BerObjectContent>,
{
parse_ber_implicit(i, tag, f)
}
/// Parse DER object and try to decode it as a 32-bits unsigned integer
pub fn parse_der_u32(i: &[u8]) -> BerResult<u32> {
match parse_ber_integer(i) {
Ok((rem, ref obj)) => match obj.content {
BerObjectContent::Integer(i) => match i.len() {
1 => Ok((rem, u32::from(i[0]))),
2 => Ok((rem, u32::from(i[0]) << 8 | u32::from(i[1]))),
3 => Ok((
rem,
u32::from(i[0]) << 16 | u32::from(i[1]) << 8 | u32::from(i[2]),
)),
4 => Ok((
rem,
u32::from(i[0]) << 24
| u32::from(i[1]) << 16
| u32::from(i[2]) << 8
| u32::from(i[3]),
)),
_ => Err(Err::Error(BerError::IntegerTooLarge)),
},
_ => Err(Err::Error(BerError::InvalidTag)),
},
Err(e) => Err(e),
}
}
/// Parse DER object and try to decode it as a 64-bits unsigned integer
pub fn parse_der_u64(i: &[u8]) -> BerResult<u64> {
match parse_ber_integer(i) {
Ok((rem, ref obj)) => match obj.content {
BerObjectContent::Integer(i) => match bytes_to_u64(i) {
Ok(l) => Ok((rem, l)),
Err(_) => Err(Err::Error(BerError::IntegerTooLarge)),
},
_ => Err(Err::Error(BerError::InvalidTag)),
},
Err(e) => Err(e),
}
}
// --------- end of parse_der_xxx functions ----------
/// Parse the next bytes as the content of a DER object.
///
/// Content type is *not* checked, caller is reponsible of providing the correct tag
pub fn der_read_element_content_as(
i: &[u8],
tag: BerTag,
len: usize,
constructed: bool,
max_depth: usize,
) -> BerResult<BerObjectContent> {
if i.len() < len {
return Err(Err::Incomplete(Needed::Size(len)));
}
match tag {
BerTag::Boolean => {
custom_check!(i, len != 1, BerError::InvalidLength)?;
der_constraint_fail_if!(i, i[0] != 0 && i[0] != 0xff);
}
BerTag::BitString => {
der_constraint_fail_if!(i, constructed);
// exception: read and verify padding bits
return der_read_content_bitstring(i, len);
}
BerTag::NumericString
| BerTag::PrintableString
| BerTag::Ia5String
| BerTag::Utf8String
| BerTag::T61String
| BerTag::BmpString
| BerTag::GeneralString => {
der_constraint_fail_if!(i, constructed);
}
BerTag::UtcTime | BerTag::GeneralizedTime => {
if len == 0 || i.get(len - 1).cloned() != Some(b'Z') {
return Err(Err::Error(BerError::DerConstraintFailed));
}
}
_ => (),
}
ber_read_element_content_as(i, tag, len, constructed, max_depth)
}
/// Parse DER object content recursively
///
/// *Note: an error is raised if recursion depth exceeds `MAX_RECURSION`.
pub fn der_read_element_content<'a>(i: &'a [u8], hdr: BerObjectHeader<'a>) -> DerResult<'a> {
der_read_element_content_recursive(i, hdr, MAX_RECURSION)
}
fn der_read_element_content_recursive<'a>(
i: &'a [u8],
hdr: BerObjectHeader<'a>,
max_depth: usize,
) -> DerResult<'a> {
match hdr.class {
BerClass::Universal | BerClass::Private => (),
_ => {
return map!(i, take!(hdr.len), |b| {
DerObject::from_header_and_content(hdr, BerObjectContent::Unknown(hdr.tag, b))
})
}
}
match der_read_element_content_as(
i,
hdr.tag,
hdr.len as usize,
hdr.is_constructed(),
max_depth,
) {
Ok((rem, content)) => Ok((rem, DerObject::from_header_and_content(hdr, content))),
Err(Err::Error(BerError::UnknownTag)) => map!(i, take!(hdr.len), |b| {
DerObject::from_header_and_content(hdr, BerObjectContent::Unknown(hdr.tag, b))
}),
Err(e) => Err(e),
}
}
fn der_read_content_bitstring(i: &[u8], len: usize) -> BerResult<BerObjectContent> {
do_parse! {
i,
ignored_bits: be_u8 >>
custom_check!(ignored_bits > 7, BerError::DerConstraintFailed) >>
custom_check!(len == 0, BerError::InvalidLength) >>
s: take!(len - 1) >>
call!(|input| {
if len > 1 {
let mut last_byte = s[len-2];
for _ in 0..ignored_bits as usize {
der_constraint_fail_if!(i, last_byte & 1 != 0);
last_byte >>= 1;
}
}
Ok((input,()))
}) >>
( BerObjectContent::BitString(ignored_bits,BitStringObject{ data:s }) )
}
}
/// Read an object header (DER)
pub fn der_read_element_header(i: &[u8]) -> BerResult<BerObjectHeader> {
do_parse! {
i,
el: parse_identifier >>
len: parse_ber_length_byte >>
llen: cond!(len.0 == 1, take!(len.1)) >>
( {
let class = match BerClass::try_from(el.0) {
Ok(c) => c,
Err(_) => unreachable!(), // Cannot fail, we read only 2 bits
};
let len : u64 = match len.0 {
0 => u64::from(len.1),
_ => {
// if len is 0xff -> error (8.1.3.5)
custom_check!(&i[1..], len.1 == 0b0111_1111, BerError::InvalidLength)?;
// if len.1 == 0b0111_1111 {
// return Err(::nom::Err::Error(error_position!(&i[1..], ErrorKind::Custom(BER_INVALID_LENGTH))));
// }
// DER(9.1) if len is 0 (indefinite form), obj must be constructed
der_constraint_fail_if!(&i[1..], len.1 == 0 && el.1 != 1);
// if len.1 == 0 && el.1 != 1 {
// return Err(::nom::Err::Error(error_position!(&i[1..], ErrorKind::Custom(BER_INVALID_LENGTH))));
// }
let llen = llen.unwrap(); // safe because we tested len.0 != 0
match bytes_to_u64(llen) {
Ok(l) => {
// DER: should have been encoded in short form (< 127)
der_constraint_fail_if!(i, l < 127);
l
},
Err(_) => { return Err(::nom::Err::Error(BerError::InvalidTag)); },
}
},
};
BerObjectHeader::new(class, el.1, BerTag(el.2), len).with_raw_tag(Some(el.3))
} )
}
}