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use std::collections::HashMap;
use super::pubkey::{PublicKey, PublicKeyKind};
/// A `Writer` is used for encoding a key in OpenSSH compatible format.
#[derive(Debug)]
pub struct Writer {
inner: Vec<u8>,
}
impl Writer {
/// Creates a new `Writer` instance.
///
/// # Example
/// ```rust
/// # use sshcerts::ssh::Writer;
/// let writer = Writer::new();
/// ```
pub fn new() -> Writer {
Writer { inner: Vec::new() }
}
/// Write a cstring to the underlying vector
///
/// # Example
/// ```rust
/// # use sshcerts::ssh::Writer;
/// let mut writer = Writer::new();
/// writer.write_cstring("AAAA");
/// let bytes = writer.into_bytes();
/// assert_eq!(bytes, vec![65, 65, 65, 65, 00]);
/// ```
pub fn write_cstring(&mut self, s: &str) {
let bytes = s.as_bytes();
self.inner.extend_from_slice(bytes);
self.inner.push(0x0);
}
/// Writes a byte sequence to the underlying vector.
/// The value is represented as a the byte sequence length,
/// followed by the actual byte sequence.
///
/// # Example
/// ```rust
/// # use sshcerts::ssh::Writer;
/// let mut writer = Writer::new();
/// writer.write_bytes(&[0, 0, 0, 42]);
/// let bytes = writer.into_bytes();
/// assert_eq!(bytes, vec![0, 0, 0, 4, 0, 0, 0, 42]);
/// ```
pub fn write_bytes(&mut self, val: &[u8]) {
let size = val.len() as u32;
let mut buf = size.to_be_bytes().to_vec();
self.inner.append(&mut buf);
self.inner.extend_from_slice(val);
}
/// Writes a raw byte sequence to the underlying vector.e.
///
/// # Example
/// ```rust
/// # use sshcerts::ssh::Writer;
/// let mut writer = Writer::new();
/// writer.write_raw_bytes(&[0, 0, 0, 42]);
/// let bytes = writer.into_bytes();
/// assert_eq!(bytes, vec![0, 0, 0, 42]);
/// ```
pub fn write_raw_bytes(&mut self, val: &[u8]) {
self.inner.extend_from_slice(val);
}
/// Writes a `string` value to the underlying byte sequence.
///
/// # Example
/// ```rust
/// # use sshcerts::ssh::Writer;
/// let mut writer = Writer::new();
/// writer.write_string("a test string");
/// let bytes = writer.into_bytes();
/// assert_eq!(bytes, [0, 0, 0, 13, 97, 32, 116, 101, 115, 116, 32, 115, 116, 114, 105, 110, 103]);
/// ```
pub fn write_string(&mut self, val: &str) {
self.write_bytes(val.as_bytes());
}
/// Writes a `u64` value to the underlying byte sequence.
///
/// # Example
/// ```rust
/// # use sshcerts::ssh::Writer;
/// let mut writer = Writer::new();
/// writer.write_u64(0xFFFFFFFFFFFFFFFF);
/// let bytes = writer.into_bytes();
/// assert_eq!(bytes, [255, 255, 255, 255, 255, 255, 255, 255]);
/// ```
pub fn write_u64(&mut self, val: u64) {
let bytes = val.to_be_bytes();
self.inner.extend_from_slice(&bytes);
}
/// Writes a `u32` value to the underlying byte sequence.
///
/// # Example
/// ```rust
/// # use sshcerts::ssh::Writer;
/// let mut writer = Writer::new();
/// writer.write_u32(0xFFFFFFFF);
/// let bytes = writer.into_bytes();
/// assert_eq!(bytes, [255, 255, 255, 255]);
/// ```
pub fn write_u32(&mut self, val: u32) {
let bytes = val.to_be_bytes();
self.inner.extend_from_slice(&bytes);
}
/// Writes an `mpint` value to the underlying byte sequence.
/// If the MSB bit of the first byte is set then the number is
/// negative, otherwise it is positive.
/// Positive numbers must be preceeded by a leading zero byte according to RFC 4251, section 5.
///
/// We also make a reasonable effort to fix encoding errors and only write valid, positive, mpints
///
/// # Example
/// ```rust
/// # use sshcerts::ssh::Writer;
/// let mut writer = Writer::new();
/// writer.write_mpint(&[1, 0, 1]);
/// let bytes = writer.into_bytes();
/// assert_eq!(bytes, [0, 0, 0, 3, 1, 0, 1]);
/// ```
pub fn write_mpint(&mut self, val: &[u8]) {
let mut leading_zeros = 0;
// Remove leading 0s
for item in val {
if *item == 0 {
leading_zeros += 1
} else {
break;
}
}
let val = &val[leading_zeros..];
let mut bytes = val.to_vec();
// If most significant bit is set then prepend a zero byte to
// avoid interpretation as a negative number.
if val.first().unwrap_or(&0) & 0x80 != 0 {
bytes.insert(0, 0);
}
self.write_bytes(&bytes);
}
/// Writes a `Vec<String>` to the underlying byte sequence.
///
/// # Example
/// ```rust
/// # use sshcerts::ssh::Writer;
/// let mut writer = Writer::new();
///
/// writer.write_string_vec(&vec![String::from("Test"), String::from("Test")]);
/// let bytes = writer.into_bytes();
/// assert_eq!(bytes, [0, 0, 0, 16, 0, 0, 0, 4, 84, 101, 115, 116, 0, 0, 0, 4, 84, 101, 115, 116]);
/// ```
pub fn write_string_vec(&mut self, vec: &[String]) {
let total_length = vec
.iter()
.map(|x| x.len())
.fold(vec.len() * 4, |x, y| x + y) as u32;
self.write_u32(total_length);
for item in vec {
self.write_string(item);
}
}
/// Writes a `HashMap<String, String>` to the underlying byte sequence.
///
/// # Example
/// ```rust
/// # use sshcerts::ssh::Writer;
/// # use std::collections::HashMap;
///
/// let mut writer = Writer::new();
/// let mut example_map = HashMap::new();
/// example_map.insert(String::from("Test"), String::from(""));
/// writer.write_string_map(&example_map);
/// let bytes = writer.into_bytes();
/// assert_eq!(bytes, [0, 0, 0, 12, 0, 0, 0, 4, 84, 101, 115, 116, 0, 0, 0, 0]);
/// ```
pub fn write_string_map(&mut self, map: &HashMap<String, String>) {
let total_length = map
.iter()
.map(|x| x.0.len() + x.1.len() + if !x.1.is_empty() { 4 } else { 0 })
.fold(map.len() * 8, |x, y| x + y) as u32;
self.write_u32(total_length);
for (k, v) in map {
self.write_string(k);
if v.is_empty() {
self.write_u32(0x0);
} else {
self.write_u32(v.len() as u32 + 4);
self.write_string(v);
}
}
}
/// Writes a `PublicKey` to the underlying byte sequence.
///
/// # Example
/// ```
/// ```
pub fn write_pub_key(&mut self, key: &PublicKey) {
let mut inner_writer = Writer::new();
inner_writer.write_string(key.key_type.name);
inner_writer.write_pub_key_data(key);
let pubkey_bytes = inner_writer.as_bytes();
self.write_bytes(pubkey_bytes);
}
/// Writes `PublicKey` data to the underlying byte sequence.
///
/// # Example
/// ```
/// ```
pub fn write_pub_key_data(&mut self, key: &PublicKey) {
// Write the public key
match &key.kind {
PublicKeyKind::Rsa(ref k) => {
self.write_mpint(&k.e);
self.write_mpint(&k.n);
}
PublicKeyKind::Ecdsa(ref k) => {
self.write_string(k.curve.identifier);
self.write_bytes(&k.key);
if key.key_type.is_sk {
self.write_string(k.sk_application.as_ref().unwrap());
}
}
PublicKeyKind::Ed25519(ref k) => {
self.write_bytes(&k.key);
if key.key_type.is_sk {
self.write_string(k.sk_application.as_ref().unwrap());
}
}
}
}
/// Converts the `Writer` into a byte sequence.
/// This consumes the underlying byte sequence used by the `Writer`.
///
/// # Example
/// ```rust
/// # use sshcerts::ssh::Writer;
///
/// let mut writer = Writer::new();
/// writer.write_string("some data");
/// let bytes = writer.into_bytes();
/// assert_eq!(bytes, [0, 0, 0, 9, 115, 111, 109, 101, 32, 100, 97, 116, 97]);
/// ```
pub fn into_bytes(self) -> Vec<u8> {
self.inner
}
/// Converts the `Writer` into a byte sequence.
/// This consumes the underlying byte sequence used by the `Writer`.
///
/// # Example
/// ```rust
/// # use sshcerts::ssh::Writer;
///
/// let mut writer = Writer::new();
/// writer.write_string("some data");
/// let bytes = writer.into_bytes();
/// assert_eq!(bytes, [0, 0, 0, 9, 115, 111, 109, 101, 32, 100, 97, 116, 97]);
/// ```
pub fn as_bytes(&self) -> &[u8] {
self.inner.as_slice()
}
}
impl Default for Writer {
fn default() -> Self {
Writer::new()
}
}