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pub fn asn_der_to_r_s(buf: &[u8]) -> Option<(&[u8], &[u8])> {
if buf.len() < 4 || buf[0] != 0x30 {
return None;
}
let buf = &buf[3..];
let r_length = buf[0] as usize;
if buf.len() < r_length + 2 {
return None;
}
let buf = &buf[1..];
let r = &buf[..r_length];
let buf = &buf[r_length..];
if buf[0] != 0x2 {
return None
}
let s_length = buf[1] as usize;
let s = &buf[2..];
if s.len() != s_length {
return None
}
Some((r, s))
}
pub fn signature_convert_asn1_ecdsa_to_ssh(signature: &[u8]) -> Option<Vec<u8>> {
let mut encoded = vec![];
let (r,s) = match asn_der_to_r_s(&signature) {
Some((r,s)) => (r, s),
None => return None,
};
let mut sig_encoding = vec![];
sig_encoding.extend_from_slice(&(r.len() as u32).to_be_bytes());
sig_encoding.extend_from_slice(r);
sig_encoding.extend_from_slice(&(s.len() as u32).to_be_bytes());
sig_encoding.extend_from_slice(s);
encoded.extend_from_slice(&(sig_encoding.len() as u32).to_be_bytes());
encoded.extend(sig_encoding);
Some(encoded)
}