barebones_x509/
das.rs

1//! Data-algorithm-signature ASN.1 structures
2
3use super::Error;
4use ring::io::der;
5
6/// A data-algorithm-signature structure
7#[derive(Debug, Copy, Clone)]
8pub struct DataAlgorithmSignature<'a> {
9    data: &'a [u8],
10    inner: &'a [u8],
11    algorithm: &'a [u8],
12    signature: &'a [u8],
13}
14
15impl<'a> DataAlgorithmSignature<'a> {
16    /// The data over which the signature is computed.  An X.509 SEQUENCE.
17    pub fn data(&self) -> &'a [u8] { self.data }
18    /// The data with the outer SEQUENCE stripped.
19    pub fn inner(&self) -> &'a [u8] { self.inner }
20    /// The algorithm identifier, with the outer SEQUENCE stripped.
21    pub fn algorithm(&self) -> &'a [u8] { self.algorithm }
22    /// The raw bytes of the signature.
23    pub fn signature(&self) -> &'a [u8] { self.signature }
24}
25
26pub(crate) fn read_sequence<'a>(
27    input: &mut untrusted::Reader<'a>,
28) -> Result<untrusted::Input<'a>, Error> {
29    der::expect_tag_and_get_value(input, der::Tag::Sequence).map_err(|_| Error::BadDER)
30}
31
32impl<'a> core::convert::TryFrom<&'a [u8]> for DataAlgorithmSignature<'a> {
33    type Error = Error;
34    fn try_from(value: &'a [u8]) -> Result<Self, Self::Error> {
35        untrusted::Input::from(value).read_all(Error::BadDER, |input| {
36            der::nested(input, der::Tag::Sequence, Error::BadDER, |input| {
37                // tbsCertificate
38                let (data, inner) = input.read_partial(read_sequence)?;
39                // signatureAlgorithm
40                let algorithm = read_sequence(input)?.as_slice_less_safe();
41                // signatureValue
42                let signature = der::bit_string_with_no_unused_bits(input)
43                    .map_err(|_| Error::BadDER)?
44                    .as_slice_less_safe();
45                Ok(Self {
46                    data: data.as_slice_less_safe(),
47                    inner: inner.as_slice_less_safe(),
48                    algorithm,
49                    signature,
50                })
51            })
52        })
53    }
54}
barebones_x509/das.rs

barebones_x509/
das.rs
