sspi 0.20.0

A Rust implementation of the Security Support Provider Interface (SSPI) API
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261

#[cfg(test)]
mod test;

use std::io::{self, Read, Write};
use std::sync::LazyLock;

use byteorder::{LittleEndian, ReadBytesExt, WriteBytesExt};
use rand::rngs::{StdRng, SysRng};
use rand::{RngCore, SeedableRng};
use time::OffsetDateTime;

use crate::channel_bindings::ChannelBindings;
use crate::crypto::{HASH_SIZE, compute_hmac_md5, compute_md4, compute_md5, compute_md5_channel_bindings_hash};
use crate::ntlm::messages::av_pair::*;
use crate::ntlm::{
    AuthIdentityBuffers, CHALLENGE_SIZE, LM_CHALLENGE_RESPONSE_BUFFER_SIZE, MESSAGE_INTEGRITY_CHECK_SIZE,
};
use crate::{NtlmHash, NtlmHashError, Secret, Utf16StringExt};

pub(super) const SINGLE_HOST_DATA_SIZE: usize = 48;

const NT_V2_RESPONSE_BASE_SIZE: usize = 28;

// The Single_Host_Data structure allows a client to send machine-specific information
// within an authentication exchange to services on the same machine. The client can
// produce additional information to be processed in an implementation-specific way when
// the client and server are on the same host. If the server and client platforms are
// different or if they are on different hosts, then the information MUST be ignored.
// Any fields after the MachineID field MUST be ignored on receipt.
pub(super) static SINGLE_HOST_DATA: LazyLock<[u8; SINGLE_HOST_DATA_SIZE]> = LazyLock::new(|| {
    let mut result = [0x00; SINGLE_HOST_DATA_SIZE];
    let mut buffer = io::Cursor::new(result.as_mut());

    buffer.write_u32::<LittleEndian>(SINGLE_HOST_DATA_SIZE as u32).unwrap(); //size
    buffer.write_u32::<LittleEndian>(0).unwrap(); //z4
    buffer.write_u32::<LittleEndian>(1).unwrap(); //data present
    buffer.write_u32::<LittleEndian>(0x2000).unwrap(); //custom_data
    buffer.write_all([0xaa; 32].as_ref()).unwrap(); //machine_id

    result
});

fn convert_to_file_time(end_date: OffsetDateTime) -> crate::Result<u64> {
    let start_date = time::Date::from_calendar_date(1601, time::Month::January, 1)
        .expect("hardcoded")
        .with_hms(0, 1, 1)
        .expect("hardcoded")
        .assume_utc();

    if start_date > end_date {
        Err(crate::Error::new(
            crate::ErrorKind::InternalError,
            format!(
                "Failed to convert system time to file time, where the start date: {start_date:?}, end date: {end_date:?}"
            ),
        ))
    } else {
        let duration = end_date - start_date;
        let whole_microseconds = duration.whole_microseconds();
        let file_time = u64::try_from(whole_microseconds).expect("whole_microseconds to u64 conversion") * 10;
        Ok(file_time)
    }
}

pub(super) fn get_challenge_target_info(timestamp: u64) -> crate::Result<Vec<u8>> {
    // Windows requires _DomainName, _ComputerName fields, but does not care what they are contain
    let av_pairs = vec![
        AvPair::NbDomainName(Vec::new()),
        AvPair::NbComputerName(Vec::new()),
        AvPair::DnsDomainName(Vec::new()),
        AvPair::DnsComputerName(Vec::new()),
        AvPair::Timestamp(timestamp),
        AvPair::EOL,
    ];

    Ok(AvPair::list_to_buffer(&av_pairs)?)
}

pub(super) fn get_authenticate_target_info(
    target_info: &[u8],
    channel_bindings: Option<&ChannelBindings>,
    send_single_host_data: bool,
) -> crate::Result<Vec<u8>> {
    let mut av_pairs = AvPair::buffer_to_av_pairs(target_info)?;

    av_pairs.retain(|av_pair| av_pair.as_u16() != AV_PAIR_EOL);

    // use_mic always true, when ntlm_v2 is true
    let flags_av_pair = AvPair::Flags(MsvAvFlags::MESSAGE_INTEGRITY_CHECK.bits());
    av_pairs.push(flags_av_pair);

    if send_single_host_data {
        let single_host_av_pair = AvPair::SingleHost(*SINGLE_HOST_DATA);
        av_pairs.push(single_host_av_pair);
    }

    // will not check suppress_extended_protection and
    // will not add channel bindings and service principal name
    // because it is not used anywhere

    if let Some(channel_bindings) = channel_bindings {
        av_pairs.push(AvPair::ChannelBindings(compute_md5_channel_bindings_hash(
            channel_bindings,
        )));
    }

    let mut authenticate_target_info = AvPair::list_to_buffer(&av_pairs)?;

    // NTLMv2
    // unknown 8-byte padding: AvEOL ([0x00; 4]) + reserved ([0x00; 4])
    authenticate_target_info.write_u64::<LittleEndian>(0x00)?;

    Ok(authenticate_target_info)
}

pub(super) fn generate_challenge() -> crate::Result<[u8; CHALLENGE_SIZE]> {
    let mut challenge = [0; CHALLENGE_SIZE];
    let mut rand = StdRng::try_from_rng(&mut SysRng)?;
    rand.fill_bytes(challenge.as_mut());
    Ok(challenge)
}

pub(super) fn now_file_time_timestamp() -> crate::Result<u64> {
    convert_to_file_time(OffsetDateTime::now_utc())
}

pub(crate) fn generate_signing_key(exported_session_key: &[u8], sign_magic: &[u8]) -> Secret<[u8; HASH_SIZE]> {
    let mut value = exported_session_key.to_vec();
    value.extend_from_slice(sign_magic);
    Secret::new(compute_md5(value.as_ref()))
}

pub(super) fn compute_message_integrity_check(
    negotiate_message: &[u8],
    challenge_message: &[u8],
    authenticate_message: &[u8],
    exported_session_key: &[u8],
) -> io::Result<[u8; MESSAGE_INTEGRITY_CHECK_SIZE]> {
    let mut message_integrity_check = negotiate_message.to_vec();
    message_integrity_check.extend_from_slice(challenge_message);
    message_integrity_check.extend_from_slice(authenticate_message);

    compute_hmac_md5(exported_session_key, message_integrity_check.as_ref())
}

pub(super) fn compute_ntlm_v2_hash(identity: &AuthIdentityBuffers) -> crate::Result<[u8; HASH_SIZE]> {
    if !identity.is_empty() {
        let password_bytes = identity.password.as_ref().0.as_bytes_le();
        let password_str = identity.password.as_ref().0.to_string();

        // Check if the password field contains an NT hash with the prefix.
        let hmac_key = if let Some(hash_hex) = password_str.strip_prefix(crate::ntlm::hash::NTLM_HASH_PREFIX) {
            let nt_hash: NtlmHash = hash_hex.parse().map_err(|e| match e {
                NtlmHashError::StringLength => crate::Error::new(
                    crate::ErrorKind::InvalidToken,
                    "NT hash must be exactly 32 hex characters",
                ),
                NtlmHashError::Hex => {
                    crate::Error::new(crate::ErrorKind::InvalidToken, "Invalid hex character in NT hash")
                }
                NtlmHashError::ByteLength => unreachable!(),
            })?;

            *nt_hash.as_bytes()
        } else {
            compute_md4(password_bytes)
        };

        let mut user_uppercase_with_domain = identity.user.to_uppercase().to_bytes_le();
        user_uppercase_with_domain.extend(identity.domain.as_bytes_le());

        Ok(compute_hmac_md5(&hmac_key, &user_uppercase_with_domain)?)
    } else {
        Err(crate::Error::new(
            crate::ErrorKind::InvalidToken,
            String::from("Got empty identity"),
        ))
    }
    // hash by the callback is not implemented because the callback never sets
}

pub(super) fn compute_lm_v2_response(
    client_challenge: &[u8],
    server_challenge: &[u8],
    ntlm_v2_hash: &[u8],
) -> crate::Result<[u8; LM_CHALLENGE_RESPONSE_BUFFER_SIZE]> {
    let mut lm_challenge_data = [0x00; CHALLENGE_SIZE * 2];
    lm_challenge_data[0..CHALLENGE_SIZE].clone_from_slice(server_challenge);
    lm_challenge_data[CHALLENGE_SIZE..].clone_from_slice(client_challenge);

    let mut lm_challenge_response = [0x00; LM_CHALLENGE_RESPONSE_BUFFER_SIZE];
    lm_challenge_response[0..HASH_SIZE].clone_from_slice(compute_hmac_md5(ntlm_v2_hash, &lm_challenge_data)?.as_ref());
    lm_challenge_response[HASH_SIZE..].clone_from_slice(client_challenge);
    Ok(lm_challenge_response)
}

pub(super) fn compute_ntlm_v2_response(
    client_challenge: &[u8],
    server_challenge: &[u8],
    target_info: &[u8],
    ntlm_v2_hash: &[u8],
    timestamp: u64,
) -> crate::Result<(Vec<u8>, [u8; HASH_SIZE])> {
    let mut ntlm_v2_temp = Vec::with_capacity(NT_V2_RESPONSE_BASE_SIZE);
    ntlm_v2_temp.write_u8(1)?; // RespType 1 byte
    ntlm_v2_temp.write_u8(1)?; // HighRespType 1 byte
    ntlm_v2_temp.write_u16::<LittleEndian>(0)?; // Reserved1 2 bytes
    ntlm_v2_temp.write_u32::<LittleEndian>(0)?; // Reserved2 4 bytes
    ntlm_v2_temp.write_u64::<LittleEndian>(timestamp)?; // Timestamp 8 bytes
    ntlm_v2_temp.extend(client_challenge); // ClientChallenge 8 bytes
    ntlm_v2_temp.write_u32::<LittleEndian>(0)?; // Reserved3 4 bytes
    ntlm_v2_temp.extend(target_info); // TargetInfo

    let mut nt_proof_input = server_challenge.to_vec();
    nt_proof_input.extend(ntlm_v2_temp.as_slice());
    let nt_proof = compute_hmac_md5(ntlm_v2_hash, nt_proof_input.as_ref())?;

    let mut nt_challenge_response = nt_proof.to_vec();
    nt_challenge_response.append(ntlm_v2_temp.as_mut());

    let key_exchange_key = compute_hmac_md5(ntlm_v2_hash, nt_proof.as_ref())?;

    Ok((nt_challenge_response, key_exchange_key))
}

pub(super) fn read_ntlm_v2_response(mut challenge_response: &[u8]) -> io::Result<(Vec<u8>, [u8; CHALLENGE_SIZE])> {
    let mut response = [0x00; HASH_SIZE];
    challenge_response.read_exact(response.as_mut())?;
    let _resp_type = challenge_response.read_u8()?;
    let _hi_resp_type = challenge_response.read_u8()?;
    let _reserved1 = challenge_response.read_u16::<LittleEndian>()?;
    let _reserved2 = challenge_response.read_u32::<LittleEndian>()?;
    let _timestamp = challenge_response.read_u64::<LittleEndian>()?;

    let mut client_challenge = [0x00; CHALLENGE_SIZE];
    challenge_response.read_exact(client_challenge.as_mut())?;
    let _reserved3 = challenge_response.read_u32::<LittleEndian>()?;

    let mut av_pairs = Vec::with_capacity(challenge_response.len());
    challenge_response.read_to_end(&mut av_pairs)?;

    Ok((av_pairs, client_challenge))
}

pub(super) fn get_av_flags_from_response(av_pairs: &[AvPair]) -> io::Result<MsvAvFlags> {
    if let Some(AvPair::Flags(value)) = av_pairs.iter().find(|&av_pair| av_pair.as_u16() == AV_PAIR_FLAGS) {
        Ok(MsvAvFlags::from_bits(*value).unwrap_or_else(MsvAvFlags::empty))
    } else {
        Ok(MsvAvFlags::empty())
    }
}

pub(super) fn get_challenge_timestamp_from_response(target_info: &[u8]) -> crate::Result<u64> {
    let av_pairs = AvPair::buffer_to_av_pairs(target_info)?;

    if let Some(AvPair::Timestamp(value)) = av_pairs.iter().find(|&av_pair| av_pair.as_u16() == AV_PAIR_TIMESTAMP) {
        Ok(*value)
    } else {
        now_file_time_timestamp()
    }
}