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| 1 | +/* |
| 2 | + * Copyright (C) 2025 wolfSSL Inc. |
| 3 | + * |
| 4 | + * This file is part of wolfSSL. |
| 5 | + * |
| 6 | + * wolfSSL is free software; you can redistribute it and/or modify |
| 7 | + * it under the terms of the GNU General Public License as published by |
| 8 | + * the Free Software Foundation; either version 3 of the License, or |
| 9 | + * (at your option) any later version. |
| 10 | + * |
| 11 | + * wolfSSL is distributed in the hope that it will be useful, |
| 12 | + * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 13 | + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 14 | + * GNU General Public License for more details. |
| 15 | + * |
| 16 | + * You should have received a copy of the GNU General Public License |
| 17 | + * along with this program; if not, write to the Free Software |
| 18 | + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1335, USA |
| 19 | + */ |
| 20 | + |
| 21 | +/*! |
| 22 | +This module provides a Rust wrapper for the wolfCrypt library's Key Derivation |
| 23 | +Function (KDF) functionality. |
| 24 | +
|
| 25 | +It leverages the `wolfssl-sys` crate for low-level FFI bindings, encapsulating |
| 26 | +the raw C functions in a memory-safe and easy-to-use Rust API. |
| 27 | +*/ |
| 28 | + |
| 29 | +use crate::wolfcrypt::hmac::HMAC; |
| 30 | +use wolfssl_sys as ws; |
| 31 | + |
| 32 | +/// Perform RFC 5869 HKDF-Extract operation for TLS v1.3 key derivation. |
| 33 | +/// |
| 34 | +/// # Parameters |
| 35 | +/// |
| 36 | +/// * `typ`: Hash type, one of `HMAC::TYPE_*`. |
| 37 | +/// * `salt`: Optional Salt value. |
| 38 | +/// * `key`: Optional Initial Key Material (IKM). |
| 39 | +/// * `out`: Output buffer to store TLS1.3 HKDF-Extract result (generated |
| 40 | +/// Pseudo-Random Key (PRK)). The size of this buffer must match |
| 41 | +/// `HMAC::get_hmac_size_by_type(typ)`. |
| 42 | +/// |
| 43 | +/// # Returns |
| 44 | +/// |
| 45 | +/// Returns either Ok(()) on success or Err(e) containing the wolfSSL |
| 46 | +/// library error code value. |
| 47 | +/// |
| 48 | +/// # Example |
| 49 | +/// |
| 50 | +/// ```rust |
| 51 | +/// use wolfssl::wolfcrypt::hmac::HMAC; |
| 52 | +/// use wolfssl::wolfcrypt::kdf::*; |
| 53 | +/// use wolfssl_sys as ws; |
| 54 | +/// let mut secret = [0u8; ws::WC_SHA256_DIGEST_SIZE as usize]; |
| 55 | +/// tls13_hkdf_extract(HMAC::TYPE_SHA256, None, None, &mut secret).expect("Error with tls13_hkdf_extract()"); |
| 56 | +/// ``` |
| 57 | +pub fn tls13_hkdf_extract(typ: i32, salt: Option<&[u8]>, key: Option<&mut [u8]>, out: &mut [u8]) -> Result<(), i32> { |
| 58 | + let mut salt_ptr = core::ptr::null(); |
| 59 | + let mut salt_size = 0u32; |
| 60 | + if let Some(salt) = salt { |
| 61 | + salt_ptr = salt.as_ptr(); |
| 62 | + salt_size = salt.len() as u32; |
| 63 | + } |
| 64 | + let mut ikm_buf = [0u8; ws::WC_MAX_DIGEST_SIZE as usize]; |
| 65 | + let mut ikm_ptr = ikm_buf.as_mut_ptr(); |
| 66 | + let mut ikm_size = 0u32; |
| 67 | + if let Some(key) = key { |
| 68 | + if key.len() > 0 { |
| 69 | + ikm_ptr = key.as_mut_ptr(); |
| 70 | + ikm_size = key.len() as u32; |
| 71 | + } |
| 72 | + } |
| 73 | + if out.len() != HMAC::get_hmac_size_by_type(typ)? { |
| 74 | + return Err(ws::wolfCrypt_ErrorCodes_BUFFER_E); |
| 75 | + } |
| 76 | + let rc = unsafe { |
| 77 | + ws::wc_Tls13_HKDF_Extract(out.as_mut_ptr(), salt_ptr, salt_size, |
| 78 | + ikm_ptr, ikm_size, typ) |
| 79 | + }; |
| 80 | + if rc != 0 { |
| 81 | + return Err(rc); |
| 82 | + } |
| 83 | + Ok(()) |
| 84 | +} |
| 85 | + |
| 86 | +/// Perform RFC 5869 HKDF-Extract operation for TLS v1.3 key derivation. |
| 87 | +/// |
| 88 | +/// This utilizes HMAC to convert `key`, `label`, and `info` into a |
| 89 | +/// derived key which is written to `out`. |
| 90 | +/// |
| 91 | +/// # Parameters |
| 92 | +/// |
| 93 | +/// * `typ`: Hash type, one of `HMAC::TYPE_*`. |
| 94 | +/// * `key`: Key to use for KDF (typically output of `tls13_hkdf_extract()`). |
| 95 | +/// * `protocol`: Buffer containing TLS protocol. |
| 96 | +/// * `label`: Buffer containing label. |
| 97 | +/// * `info`: Buffer containing additional info. |
| 98 | +/// * `out`: Output buffer to store TLS1.3 HKDF-Expand result. The buffer can be |
| 99 | +/// any size. |
| 100 | +/// |
| 101 | +/// # Returns |
| 102 | +/// |
| 103 | +/// Returns either Ok(()) on success or Err(e) containing the wolfSSL |
| 104 | +/// library error code value. |
| 105 | +/// |
| 106 | +/// # Example |
| 107 | +/// |
| 108 | +/// ```rust |
| 109 | +/// use wolfssl::wolfcrypt::hmac::HMAC; |
| 110 | +/// use wolfssl::wolfcrypt::kdf::*; |
| 111 | +/// use wolfssl_sys as ws; |
| 112 | +/// let hash_hello1 = [ |
| 113 | +/// 0x63u8, 0x83, 0x58, 0xab, 0x36, 0xcd, 0x0c, 0xf3, |
| 114 | +/// 0x26, 0x07, 0xb5, 0x5f, 0x0b, 0x8b, 0x45, 0xd6, |
| 115 | +/// 0x7d, 0x5b, 0x42, 0xdc, 0xa8, 0xaa, 0x06, 0xfb, |
| 116 | +/// 0x20, 0xa5, 0xbb, 0x85, 0xdb, 0x54, 0xd8, 0x8b |
| 117 | +/// ]; |
| 118 | +/// let client_early_traffic_secret = [ |
| 119 | +/// 0x20u8, 0x18, 0x72, 0x7c, 0xde, 0x3a, 0x85, 0x17, 0x72, 0xdc, 0xd7, 0x72, |
| 120 | +/// 0xb0, 0xfc, 0x45, 0xd0, 0x62, 0xb9, 0xbb, 0x38, 0x69, 0x05, 0x7b, 0xb4, |
| 121 | +/// 0x5e, 0x58, 0x5d, 0xed, 0xcd, 0x0b, 0x96, 0xd3 |
| 122 | +/// ]; |
| 123 | +/// let mut secret = [0u8; ws::WC_SHA256_DIGEST_SIZE as usize]; |
| 124 | +/// tls13_hkdf_extract(HMAC::TYPE_SHA256, None, None, &mut secret).expect("Error with tls13_hkdf_extract()"); |
| 125 | +/// let protocol_label = b"tls13 "; |
| 126 | +/// let ce_traffic_label = b"c e traffic"; |
| 127 | +/// let mut expand_out = [0u8; ws::WC_SHA256_DIGEST_SIZE as usize]; |
| 128 | +/// tls13_hkdf_expand_label(HMAC::TYPE_SHA256, &secret, |
| 129 | +/// protocol_label, ce_traffic_label, |
| 130 | +/// &hash_hello1, &mut expand_out).expect("Error with tls13_hkdf_expand_label()"); |
| 131 | +/// ``` |
| 132 | +pub fn tls13_hkdf_expand_label(typ: i32, key: &[u8], protocol: &[u8], label: &[u8], info: &[u8], out: &mut [u8]) -> Result<(), i32> { |
| 133 | + let key_size = key.len() as u32; |
| 134 | + let protocol_size = protocol.len() as u32; |
| 135 | + let label_size = label.len() as u32; |
| 136 | + let info_size = info.len() as u32; |
| 137 | + let out_size = out.len() as u32; |
| 138 | + let rc = unsafe { |
| 139 | + ws::wc_Tls13_HKDF_Expand_Label(out.as_mut_ptr(), out_size, |
| 140 | + key.as_ptr(), key_size, protocol.as_ptr(), protocol_size, |
| 141 | + label.as_ptr(), label_size, info.as_ptr(), info_size, typ) |
| 142 | + }; |
| 143 | + if rc != 0 { |
| 144 | + return Err(rc); |
| 145 | + } |
| 146 | + Ok(()) |
| 147 | +} |
| 148 | + |
| 149 | +/// Perform SSH KDF operation. |
| 150 | +/// |
| 151 | +/// # Parameters |
| 152 | +/// |
| 153 | +/// * `typ`: Hash type, one of `HMAC::TYPE_*`. |
| 154 | +/// * `key_id`: Key ID, typically 'A' through 'F'. |
| 155 | +/// * `k`: Initial key. |
| 156 | +/// * `h`: Exchange hash. |
| 157 | +/// * `session_id`: Unique identifier for the SSH session. |
| 158 | +/// * `key`: Output buffer. |
| 159 | +/// |
| 160 | +/// # Returns |
| 161 | +/// |
| 162 | +/// Returns either Ok(()) on success or Err(e) containing the wolfSSL |
| 163 | +/// library error code value. |
| 164 | +/// |
| 165 | +/// # Example |
| 166 | +/// |
| 167 | +/// ```rust |
| 168 | +/// use wolfssl::wolfcrypt::hmac::HMAC; |
| 169 | +/// use wolfssl::wolfcrypt::kdf::*; |
| 170 | +/// let k = [0x42u8; 256]; |
| 171 | +/// let h = [0x43u8; 32]; |
| 172 | +/// let sid = [0x44u8; 32]; |
| 173 | +/// let mut out = [0u8; 16]; |
| 174 | +/// ssh_kdf(HMAC::TYPE_SHA256, b'A', &k, &h, &sid, &mut out).expect("Error with ssh_kdf()"); |
| 175 | +/// ``` |
| 176 | +pub fn ssh_kdf(typ: i32, key_id: u8, k: &[u8], h: &[u8], session_id: &[u8], key: &mut [u8]) -> Result<(), i32> { |
| 177 | + let key_size = key.len() as u32; |
| 178 | + let k_size = k.len() as u32; |
| 179 | + let h_size = h.len() as u32; |
| 180 | + let session_size = session_id.len() as u32; |
| 181 | + let rc = unsafe { |
| 182 | + ws::wc_SSH_KDF(typ as u8, key_id, |
| 183 | + key.as_mut_ptr(), key_size, |
| 184 | + k.as_ptr(), k_size, h.as_ptr(), h_size, |
| 185 | + session_id.as_ptr(), session_size) |
| 186 | + }; |
| 187 | + if rc != 0 { |
| 188 | + return Err(rc); |
| 189 | + } |
| 190 | + Ok(()) |
| 191 | +} |
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