File
Blob: firmware/vendor/str0m/src/rtp/srtp.rs
| 1 | use std::fmt; |
| 2 | use std::panic::{RefUnwindSafe, UnwindSafe}; |
| 3 | |
| 4 | use crate::crypto::Aes128CmSha1_80Cipher; |
| 5 | use crate::crypto::dtls::{KeyingMaterial, SrtpProfile}; |
| 6 | use crate::crypto::{AeadAes128Gcm, AeadAes256Gcm, Aes128CmSha1_80}; |
| 7 | use crate::crypto::{AeadAes128GcmCipher, AeadAes256GcmCipher}; |
| 8 | use crate::crypto::{CryptoProvider, Sha1HmacProvider, SrtpProvider}; |
| 9 | use crate::io::DATAGRAM_MAX_PACKET_SIZE; |
| 10 | |
| 11 | use super::header::RtpHeader; |
| 12 | |
| 13 | // Common among various profiles(defined in RFC3711 Section 4.3) |
| 14 | const LABEL_RTP_AES: u8 = 0; |
| 15 | const LABEL_RTP_AUTHENTICATION_KEY: u8 = 1; |
| 16 | const LABEL_RTP_SALT: u8 = 2; |
| 17 | |
| 18 | const LABEL_RTCP_AES: u8 = 3; |
| 19 | const LABEL_RTCP_AUTHENTICATION_KEY: u8 = 4; |
| 20 | const LABEL_RTCP_SALT: u8 = 5; |
| 21 | |
| 22 | // header = 4 bytes |
| 23 | // ssrc = 4 bytes |
| 24 | // ssrtcp_index = 4 bytes |
| 25 | // tag = <T> bytes |
| 26 | // TOTAL overhead for SRTCP = 12 + T bytes. |
| 27 | // However, each RTCP packet must be on a 4 byte boundary since length is |
| 28 | // given in number of 4 bytes - 1 (making 0 valid). |
| 29 | |
| 30 | pub const SRTP_BLOCK_SIZE: usize = 16; |
| 31 | const SRTCP_INDEX_LEN: usize = 4; |
| 32 | const SRTCP_HEADER_LEN: usize = 8; |
| 33 | const MAX_TAG_LEN: usize = AeadAes256Gcm::TAG_LEN; |
| 34 | pub const SRTCP_OVERHEAD: usize = MAX_TAG_LEN + SRTCP_INDEX_LEN; |
| 35 | pub const SRTP_OVERHEAD: usize = MAX_TAG_LEN; |
| 36 | |
| 37 | // aws-lc-rs CTR mode requires output buffer to be input.len() + block_len - 1 |
| 38 | // This adds 15 bytes of padding that we truncate after encryption |
| 39 | const CTR_BUFFER_PADDING: usize = SRTP_BLOCK_SIZE - 1; |
| 40 | |
| 41 | /// Initial capacity for the RTP decryption scratch buffer. Sized to fit the |
| 42 | /// largest possible received datagram plus the CTR padding the AES-CM cipher |
| 43 | /// needs, so `unprotect_rtp` never has to grow the buffer in practice. |
| 44 | const RX_SCRATCH_CAPACITY: usize = DATAGRAM_MAX_PACKET_SIZE + CTR_BUFFER_PADDING; |
| 45 | |
| 46 | impl SrtpContext { |
| 47 | /// Create an SRTP context for the relevant profile using the provided keying material. |
| 48 | pub fn new( |
| 49 | crypto: &CryptoProvider, |
| 50 | profile: SrtpProfile, |
| 51 | mat: &KeyingMaterial, |
| 52 | left: bool, |
| 53 | ) -> Self { |
| 54 | let sha1_hmac_provider = crypto.sha1_hmac_provider; |
| 55 | |
| 56 | match profile { |
| 57 | SrtpProfile::AES128_CM_SHA1_80 => { |
| 58 | let key = |
| 59 | SrtpKey::<{ Aes128CmSha1_80::KEY_LEN }, { Aes128CmSha1_80::SALT_LEN }>::new( |
| 60 | mat, left, |
| 61 | ); |
| 62 | |
| 63 | let (rtp, rtcp) = Derived::aes_128_cm_sha1_80(crypto.srtp_provider, &key); |
| 64 | |
| 65 | SrtpContext { |
| 66 | rtp, |
| 67 | rtcp, |
| 68 | srtcp_index: 0, |
| 69 | sha1_hmac_provider, |
| 70 | rx_scratch: Vec::with_capacity(RX_SCRATCH_CAPACITY), |
| 71 | } |
| 72 | } |
| 73 | SrtpProfile::AEAD_AES_128_GCM => { |
| 74 | let key = SrtpKey::<{ AeadAes128Gcm::KEY_LEN }, { AeadAes128Gcm::SALT_LEN }>::new( |
| 75 | mat, left, |
| 76 | ); |
| 77 | |
| 78 | let (rtp, rtcp) = Derived::aead_aes_128_gcm(crypto.srtp_provider, &key); |
| 79 | |
| 80 | SrtpContext { |
| 81 | rtp, |
| 82 | rtcp, |
| 83 | srtcp_index: 0, |
| 84 | sha1_hmac_provider, |
| 85 | rx_scratch: Vec::with_capacity(RX_SCRATCH_CAPACITY), |
| 86 | } |
| 87 | } |
| 88 | SrtpProfile::AEAD_AES_256_GCM => { |
| 89 | let key = SrtpKey::<{ AeadAes256Gcm::KEY_LEN }, { AeadAes256Gcm::SALT_LEN }>::new( |
| 90 | mat, left, |
| 91 | ); |
| 92 | |
| 93 | let (rtp, rtcp) = Derived::aead_aes_256_gcm(crypto.srtp_provider, &key); |
| 94 | |
| 95 | SrtpContext { |
| 96 | rtp, |
| 97 | rtcp, |
| 98 | srtcp_index: 0, |
| 99 | sha1_hmac_provider, |
| 100 | rx_scratch: Vec::with_capacity(RX_SCRATCH_CAPACITY), |
| 101 | } |
| 102 | } |
| 103 | _ => panic!("Unexpected SRTP profile: {profile:?}"), |
| 104 | } |
| 105 | } |
| 106 | |
| 107 | #[cfg(test)] |
| 108 | fn new_aead_aes_128_gcm( |
| 109 | rtp_key: [u8; AeadAes128Gcm::KEY_LEN], |
| 110 | rtp_salt: [u8; AeadAes128Gcm::SALT_LEN], |
| 111 | rtcp_key: [u8; AeadAes128Gcm::KEY_LEN], |
| 112 | rtcp_salt: [u8; AeadAes128Gcm::SALT_LEN], |
| 113 | srtcp_index: u32, |
| 114 | ) -> Self { |
| 115 | let provider = crate::crypto::test_default_provider(); |
| 116 | |
| 117 | Self { |
| 118 | rtp: Derived::AeadAes128Gcm { |
| 119 | salt: rtp_salt, |
| 120 | enc: provider |
| 121 | .srtp_provider |
| 122 | .aead_aes_128_gcm() |
| 123 | .create_cipher(rtp_key, true), |
| 124 | dec: provider |
| 125 | .srtp_provider |
| 126 | .aead_aes_128_gcm() |
| 127 | .create_cipher(rtp_key, false), |
| 128 | }, |
| 129 | rtcp: Derived::AeadAes128Gcm { |
| 130 | salt: rtcp_salt, |
| 131 | enc: provider |
| 132 | .srtp_provider |
| 133 | .aead_aes_128_gcm() |
| 134 | .create_cipher(rtcp_key, true), |
| 135 | dec: provider |
| 136 | .srtp_provider |
| 137 | .aead_aes_128_gcm() |
| 138 | .create_cipher(rtcp_key, false), |
| 139 | }, |
| 140 | srtcp_index, |
| 141 | sha1_hmac_provider: provider.sha1_hmac_provider, |
| 142 | rx_scratch: Vec::with_capacity(RX_SCRATCH_CAPACITY), |
| 143 | } |
| 144 | } |
| 145 | |
| 146 | #[cfg(test)] |
| 147 | fn new_aead_aes_256_gcm( |
| 148 | rtp_key: [u8; AeadAes256Gcm::KEY_LEN], |
| 149 | rtp_salt: [u8; AeadAes256Gcm::SALT_LEN], |
| 150 | rtcp_key: [u8; AeadAes256Gcm::KEY_LEN], |
| 151 | rtcp_salt: [u8; AeadAes256Gcm::SALT_LEN], |
| 152 | srtcp_index: u32, |
| 153 | ) -> Self { |
| 154 | let provider = crate::crypto::test_default_provider(); |
| 155 | |
| 156 | Self { |
| 157 | rtp: Derived::AeadAes256Gcm { |
| 158 | salt: rtp_salt, |
| 159 | enc: provider |
| 160 | .srtp_provider |
| 161 | .aead_aes_256_gcm() |
| 162 | .create_cipher(rtp_key, true), |
| 163 | dec: provider |
| 164 | .srtp_provider |
| 165 | .aead_aes_256_gcm() |
| 166 | .create_cipher(rtp_key, false), |
| 167 | }, |
| 168 | rtcp: Derived::AeadAes256Gcm { |
| 169 | salt: rtcp_salt, |
| 170 | enc: provider |
| 171 | .srtp_provider |
| 172 | .aead_aes_256_gcm() |
| 173 | .create_cipher(rtcp_key, true), |
| 174 | dec: provider |
| 175 | .srtp_provider |
| 176 | .aead_aes_256_gcm() |
| 177 | .create_cipher(rtcp_key, false), |
| 178 | }, |
| 179 | srtcp_index, |
| 180 | sha1_hmac_provider: provider.sha1_hmac_provider, |
| 181 | rx_scratch: Vec::with_capacity(RX_SCRATCH_CAPACITY), |
| 182 | } |
| 183 | } |
| 184 | } |
| 185 | |
| 186 | #[derive(Debug)] |
| 187 | pub struct SrtpContext { |
| 188 | /// Encryption/decryption derived from srtp_key for RTP. |
| 189 | rtp: Derived, |
| 190 | /// Encryption/decryption derived from srtp_key for RTCP. |
| 191 | rtcp: Derived, |
| 192 | /// Counter for outgoing SRTCP packets. |
| 193 | srtcp_index: u32, |
| 194 | /// SHA1-HMAC provider for AES_128_CM_SHA1_80 profile. |
| 195 | sha1_hmac_provider: &'static dyn Sha1HmacProvider, |
| 196 | /// Reusable scratch buffer for RTP decryption output. Reused across calls |
| 197 | /// to `unprotect_rtp` so we don't allocate a fresh `Vec` per packet. |
| 198 | rx_scratch: Vec<u8>, |
| 199 | } |
| 200 | |
| 201 | /// SrtpContext contains cipher contexts that can't observe broken invariants after a panic. |
| 202 | impl UnwindSafe for SrtpContext {} |
| 203 | impl RefUnwindSafe for SrtpContext {} |
| 204 | |
| 205 | impl SrtpContext { |
| 206 | pub fn protect_rtp( |
| 207 | &mut self, |
| 208 | buf: &[u8], |
| 209 | header: &RtpHeader, |
| 210 | srtp_index: u64, // same as ext_seq |
| 211 | ) -> Vec<u8> { |
| 212 | // SRTP layout |
| 213 | // [header, [rtp, (padding + pad_count)], tag] |
| 214 | |
| 215 | // 0 1 2 3 |
| 216 | // 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 |
| 217 | // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+<+ |
| 218 | // |V=2|P|X| CC |M| PT | sequence number | | |
| 219 | // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |
| 220 | // | timestamp | | |
| 221 | // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |
| 222 | // | synchronization source (SSRC) identifier | | |
| 223 | // +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+ | |
| 224 | // | contributing source (CSRC) identifiers | | |
| 225 | // | .... | | |
| 226 | // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |
| 227 | // | RTP extension (OPTIONAL) | | |
| 228 | // +>+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |
| 229 | // | | payload ... | | |
| 230 | // | | +-------------------------------+ | |
| 231 | // | | | RTP padding | RTP pad count | | |
| 232 | // +>+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+<+ |
| 233 | // | ~ SRTP MKI (OPTIONAL) ~ | |
| 234 | // | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |
| 235 | // | : authentication tag (RECOMMENDED) : | |
| 236 | // | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | |
| 237 | // | | |
| 238 | // +- Encrypted Portion* Authenticated Portion ---+ |
| 239 | let hlen = header.header_len; |
| 240 | let input = &buf[hlen..]; |
| 241 | |
| 242 | match &mut self.rtp { |
| 243 | Derived::Aes128CmSha1_80 { key, salt, enc, .. } => { |
| 244 | // arbitrary body lengths are fine: the output buffer below is |
| 245 | // allocated with the CTR scratch the ciphers need and truncated |
| 246 | // after encryption, so no 16-byte alignment is required. |
| 247 | let iv = Aes128CmSha1_80::rtp_iv(*salt, *header.ssrc, srtp_index); |
| 248 | |
| 249 | // Allocate buffer with CTR padding (aws-lc-rs requirement) |
| 250 | // HMAC_TAG_LEN is 10, CTR_BUFFER_PADDING is 15, so we need 5 extra bytes |
| 251 | let padding_needed = |
| 252 | CTR_BUFFER_PADDING.saturating_sub(Aes128CmSha1_80::HMAC_TAG_LEN); |
| 253 | let mut output = |
| 254 | vec![0_u8; buf.len() + Aes128CmSha1_80::HMAC_TAG_LEN + padding_needed]; |
| 255 | |
| 256 | enc.encrypt(&iv, input, &mut output[hlen..]) |
| 257 | .expect("rtp encrypt"); |
| 258 | |
| 259 | output[..hlen].copy_from_slice(&buf[..hlen]); |
| 260 | |
| 261 | let hmac_start = buf.len(); |
| 262 | let sha1_hmac = |k: &[u8], p: &[&[u8]]| self.sha1_hmac_provider.sha1_hmac(k, p); |
| 263 | Aes128CmSha1_80::rtp_hmac(sha1_hmac, key, &mut output, srtp_index, hmac_start); |
| 264 | |
| 265 | output.truncate(buf.len() + Aes128CmSha1_80::HMAC_TAG_LEN); |
| 266 | output |
| 267 | } |
| 268 | Derived::AeadAes128Gcm { salt, enc, .. } => { |
| 269 | let roc = (srtp_index >> 16) as u32; |
| 270 | |
| 271 | let iv = AeadAes128Gcm::rtp_iv(*salt, *header.ssrc, roc, header.sequence_number); |
| 272 | let aad = &buf[..hlen]; |
| 273 | |
| 274 | // Input and output lengths for encryption: |
| 275 | // https://www.rfc-editor.org/rfc/rfc7714#section-5.2.1 |
| 276 | let mut output = vec![0_u8; buf.len() + AeadAes128Gcm::TAG_LEN]; |
| 277 | enc.encrypt(&iv, aad, input, &mut output[hlen..]) |
| 278 | .expect("rtp encrypt"); |
| 279 | |
| 280 | output[..hlen].copy_from_slice(aad); |
| 281 | |
| 282 | output |
| 283 | } |
| 284 | Derived::AeadAes256Gcm { salt, enc, .. } => { |
| 285 | let roc = (srtp_index >> 16) as u32; |
| 286 | |
| 287 | let iv = AeadAes256Gcm::rtp_iv(*salt, *header.ssrc, roc, header.sequence_number); |
| 288 | let aad = &buf[..hlen]; |
| 289 | |
| 290 | // Input and output lengths for encryption: |
| 291 | // https://www.rfc-editor.org/rfc/rfc7714#section-5.2.1 |
| 292 | let mut output = vec![0_u8; buf.len() + AeadAes256Gcm::TAG_LEN]; |
| 293 | enc.encrypt(&iv, aad, input, &mut output[hlen..]) |
| 294 | .expect("rtp encrypt"); |
| 295 | |
| 296 | output[..hlen].copy_from_slice(aad); |
| 297 | |
| 298 | output |
| 299 | } |
| 300 | } |
| 301 | } |
| 302 | |
| 303 | /// Decrypts an SRTP packet into the internal reusable scratch buffer and |
| 304 | /// returns a slice of the plaintext bytes. The returned slice borrows from |
| 305 | /// `self` until the next mutable use; the scratch buffer is reused across |
| 306 | /// calls to avoid per-packet allocation. |
| 307 | pub fn unprotect_rtp( |
| 308 | &mut self, |
| 309 | buf: &[u8], |
| 310 | header: &RtpHeader, |
| 311 | srtp_index: u64, // same as ext_seq |
| 312 | ) -> Option<&[u8]> { |
| 313 | match &mut self.rtp { |
| 314 | Derived::Aes128CmSha1_80 { key, salt, dec, .. } => { |
| 315 | if buf.len() < header.header_len + Aes128CmSha1_80::HMAC_TAG_LEN { |
| 316 | return None; |
| 317 | } |
| 318 | |
| 319 | let hmac_start = buf.len() - Aes128CmSha1_80::HMAC_TAG_LEN; |
| 320 | |
| 321 | let sha1_hmac = |k: &[u8], p: &[&[u8]]| self.sha1_hmac_provider.sha1_hmac(k, p); |
| 322 | if !Aes128CmSha1_80::rtp_verify( |
| 323 | sha1_hmac, |
| 324 | key, |
| 325 | &buf[..hmac_start], |
| 326 | srtp_index, |
| 327 | &buf[hmac_start..], |
| 328 | ) { |
| 329 | trace!("unprotect_rtp hmac verify fail"); |
| 330 | return None; |
| 331 | } |
| 332 | |
| 333 | let iv = Aes128CmSha1_80::rtp_iv(*salt, *header.ssrc, srtp_index); |
| 334 | |
| 335 | let input = &buf[header.header_len..hmac_start]; |
| 336 | // Sized with CTR padding (aws-lc-rs requirement). |
| 337 | self.rx_scratch.resize(input.len() + CTR_BUFFER_PADDING, 0); |
| 338 | |
| 339 | if let Err(e) = dec.decrypt(&iv, input, &mut self.rx_scratch) { |
| 340 | warn!( |
| 341 | "Failed to decrypt SRTP {} ({}): {}", |
| 342 | self.rtp.profile(), |
| 343 | error_details(header, srtp_index), |
| 344 | e |
| 345 | ); |
| 346 | return None; |
| 347 | }; |
| 348 | |
| 349 | Some(&self.rx_scratch[..input.len()]) |
| 350 | } |
| 351 | Derived::AeadAes128Gcm { salt, dec, .. } => { |
| 352 | if buf.len() < header.header_len + AeadAes128Gcm::TAG_LEN { |
| 353 | return None; |
| 354 | } |
| 355 | |
| 356 | let roc: u32 = (srtp_index >> 16) as u32; |
| 357 | let seq = header.sequence_number; |
| 358 | |
| 359 | let iv = AeadAes128Gcm::rtp_iv(*salt, *header.ssrc, roc, seq); |
| 360 | |
| 361 | let (aad, input) = buf.split_at(header.header_len); |
| 362 | // Input and output lengths for decryption: |
| 363 | // https://www.rfc-editor.org/rfc/rfc7714#section-5.2.2 |
| 364 | let out_len = input.len() - AeadAes128Gcm::TAG_LEN; |
| 365 | self.rx_scratch.resize(out_len, 0); |
| 366 | |
| 367 | match dec.decrypt(&iv, &[aad], input, &mut self.rx_scratch) { |
| 368 | Ok(v) => v, |
| 369 | Err(e) => { |
| 370 | warn!( |
| 371 | "Failed to decrypt SRTP {} ({}): {}", |
| 372 | self.rtp.profile(), |
| 373 | error_details(header, srtp_index), |
| 374 | e |
| 375 | ); |
| 376 | return None; |
| 377 | } |
| 378 | }; |
| 379 | |
| 380 | Some(&self.rx_scratch[..out_len]) |
| 381 | } |
| 382 | Derived::AeadAes256Gcm { salt, dec, .. } => { |
| 383 | if buf.len() < header.header_len + AeadAes256Gcm::TAG_LEN { |
| 384 | return None; |
| 385 | } |
| 386 | |
| 387 | let roc: u32 = (srtp_index >> 16) as u32; |
| 388 | let seq = header.sequence_number; |
| 389 | |
| 390 | let iv = AeadAes256Gcm::rtp_iv(*salt, *header.ssrc, roc, seq); |
| 391 | |
| 392 | let (aad, input) = buf.split_at(header.header_len); |
| 393 | // Input and output lengths for decryption: |
| 394 | // https://www.rfc-editor.org/rfc/rfc7714#section-5.2.2 |
| 395 | let out_len = input.len() - AeadAes256Gcm::TAG_LEN; |
| 396 | self.rx_scratch.resize(out_len, 0); |
| 397 | |
| 398 | match dec.decrypt(&iv, &[aad], input, &mut self.rx_scratch) { |
| 399 | Ok(v) => v, |
| 400 | Err(e) => { |
| 401 | warn!( |
| 402 | "Failed to decrypt SRTP {} ({}): {}", |
| 403 | self.rtp.profile(), |
| 404 | error_details(header, srtp_index), |
| 405 | e |
| 406 | ); |
| 407 | return None; |
| 408 | } |
| 409 | }; |
| 410 | |
| 411 | Some(&self.rx_scratch[..out_len]) |
| 412 | } |
| 413 | } |
| 414 | } |
| 415 | |
| 416 | pub fn protect_rtcp(&mut self, buf: &[u8]) -> Vec<u8> { |
| 417 | let srtcp_index = self.srtcp_index; |
| 418 | |
| 419 | // https://tools.ietf.org/html/rfc3711#page-15 |
| 420 | // The SRTCP index MUST be set to zero before the first SRTCP |
| 421 | // packet is sent, and MUST be incremented by one, |
| 422 | // modulo 2^31, after each SRTCP packet is sent. |
| 423 | self.srtcp_index = (self.srtcp_index + 1) % 2_u32.pow(31); |
| 424 | |
| 425 | // e is always encrypted, rest is 31 byte index. |
| 426 | let e_and_si = 0x8000_0000 | srtcp_index; |
| 427 | let ssrc = u32::from_be_bytes([buf[4], buf[5], buf[6], buf[7]]); |
| 428 | |
| 429 | if ssrc == 0 { |
| 430 | warn!("SSRC 0 does not make a good SRTCP IV"); |
| 431 | } |
| 432 | |
| 433 | match &mut self.rtcp { |
| 434 | Derived::Aes128CmSha1_80 { key, salt, enc, .. } => { |
| 435 | let iv = Aes128CmSha1_80::rtp_iv(*salt, ssrc, srtcp_index as u64); |
| 436 | |
| 437 | let final_size = buf.len() + SRTCP_INDEX_LEN + Aes128CmSha1_80::HMAC_TAG_LEN; |
| 438 | // Allocate buffer with CTR padding (aws-lc-rs requirement) |
| 439 | // SRTCP_INDEX_LEN + HMAC_TAG_LEN is 14, CTR_BUFFER_PADDING is 15, so we need 1 extra byte |
| 440 | let padding_needed = CTR_BUFFER_PADDING |
| 441 | .saturating_sub(SRTCP_INDEX_LEN + Aes128CmSha1_80::HMAC_TAG_LEN); |
| 442 | let mut output = vec![0_u8; final_size + padding_needed]; |
| 443 | |
| 444 | output[0..8].copy_from_slice(&buf[0..8]); |
| 445 | let input = &buf[8..]; |
| 446 | enc.encrypt(&iv, input, &mut output[8..]) |
| 447 | .expect("rtcp encrypt"); |
| 448 | |
| 449 | let to = &mut output[buf.len()..]; |
| 450 | to[0..4].copy_from_slice(&e_and_si.to_be_bytes()); |
| 451 | |
| 452 | let hmac_index = final_size - Aes128CmSha1_80::HMAC_TAG_LEN; |
| 453 | let sha1_hmac = |k: &[u8], p: &[&[u8]]| self.sha1_hmac_provider.sha1_hmac(k, p); |
| 454 | Aes128CmSha1_80::rtcp_hmac(sha1_hmac, key, &mut output, hmac_index); |
| 455 | |
| 456 | output.truncate(final_size); |
| 457 | output |
| 458 | } |
| 459 | Derived::AeadAes128Gcm { salt, enc, .. } => { |
| 460 | let iv = AeadAes128Gcm::rtcp_iv(*salt, ssrc, srtcp_index); |
| 461 | |
| 462 | let mut aad = [0; AeadAes128Gcm::RTCP_AAD_LEN]; |
| 463 | aad[..8].copy_from_slice(&buf[..8]); |
| 464 | aad[8..12].copy_from_slice(&e_and_si.to_be_bytes()); |
| 465 | |
| 466 | let mut output = vec![0_u8; buf.len() + SRTCP_INDEX_LEN + AeadAes128Gcm::TAG_LEN]; |
| 467 | output[0..8].copy_from_slice(&buf[0..8]); |
| 468 | let input = &buf[8..]; |
| 469 | |
| 470 | let enc_start = 8; |
| 471 | let enc_end = input.len() + 8 + AeadAes128Gcm::TAG_LEN; |
| 472 | let encout = &mut output[enc_start..enc_end]; |
| 473 | |
| 474 | enc.encrypt(&iv, &aad, input, encout).expect("rtcp encrypt"); |
| 475 | |
| 476 | let to = &mut output[enc_end..]; |
| 477 | to[0..4].copy_from_slice(&e_and_si.to_be_bytes()); |
| 478 | |
| 479 | output |
| 480 | } |
| 481 | Derived::AeadAes256Gcm { salt, enc, .. } => { |
| 482 | let iv = AeadAes256Gcm::rtcp_iv(*salt, ssrc, srtcp_index); |
| 483 | |
| 484 | let mut aad = [0; AeadAes256Gcm::RTCP_AAD_LEN]; |
| 485 | aad[..8].copy_from_slice(&buf[..8]); |
| 486 | aad[8..12].copy_from_slice(&e_and_si.to_be_bytes()); |
| 487 | |
| 488 | let mut output = vec![0_u8; buf.len() + SRTCP_INDEX_LEN + AeadAes256Gcm::TAG_LEN]; |
| 489 | output[0..8].copy_from_slice(&buf[0..8]); |
| 490 | let input = &buf[8..]; |
| 491 | |
| 492 | let enc_start = 8; |
| 493 | let enc_end = input.len() + 8 + AeadAes256Gcm::TAG_LEN; |
| 494 | let encout = &mut output[enc_start..enc_end]; |
| 495 | |
| 496 | enc.encrypt(&iv, &aad, input, encout).expect("rtcp encrypt"); |
| 497 | |
| 498 | let to = &mut output[enc_end..]; |
| 499 | to[0..4].copy_from_slice(&e_and_si.to_be_bytes()); |
| 500 | |
| 501 | output |
| 502 | } |
| 503 | } |
| 504 | } |
| 505 | |
| 506 | // SRTCP layout |
| 507 | // ["header", ssrc, payload, ["header", ssrc, payload], ...], ssrtcp_index, tag] |
| 508 | // |
| 509 | // |----------------------------------------------------------------------| |
| 510 | // authenticated |
| 511 | // |
| 512 | // |--------------------------------------| |
| 513 | // encrypted (aes) |
| 514 | pub fn unprotect_rtcp(&mut self, buf: &[u8]) -> Option<Vec<u8>> { |
| 515 | match &mut self.rtcp { |
| 516 | Derived::Aes128CmSha1_80 { key, salt, dec, .. } => { |
| 517 | if buf.len() < SRTCP_HEADER_LEN + SRTCP_INDEX_LEN + Aes128CmSha1_80::HMAC_TAG_LEN { |
| 518 | return None; |
| 519 | } |
| 520 | |
| 521 | let hmac_start = buf.len() - Aes128CmSha1_80::HMAC_TAG_LEN; |
| 522 | |
| 523 | let sha1_hmac = |k: &[u8], p: &[&[u8]]| self.sha1_hmac_provider.sha1_hmac(k, p); |
| 524 | if !Aes128CmSha1_80::rtcp_verify( |
| 525 | sha1_hmac, |
| 526 | key, |
| 527 | &buf[..hmac_start], |
| 528 | &buf[hmac_start..], |
| 529 | ) { |
| 530 | trace!("unprotect_rtcp hmac verify fail"); |
| 531 | return None; |
| 532 | } |
| 533 | |
| 534 | let idx_start = hmac_start - SRTCP_INDEX_LEN; |
| 535 | |
| 536 | let srtcp_index_be = [ |
| 537 | buf[idx_start], |
| 538 | buf[idx_start + 1], |
| 539 | buf[idx_start + 2], |
| 540 | buf[idx_start + 3], |
| 541 | ]; |
| 542 | |
| 543 | // E-flag and SRTCP index. |
| 544 | let e_and_si = u32::from_be_bytes(srtcp_index_be); |
| 545 | |
| 546 | let is_encrypted = e_and_si & 0x8000_0000 > 0; |
| 547 | |
| 548 | if !is_encrypted { |
| 549 | // Non-encrypted we can just return |
| 550 | return Some(buf[0..idx_start].to_vec()); |
| 551 | } |
| 552 | |
| 553 | // The SRTCP index is a 31-bit counter for the SRTCP packet. |
| 554 | let srtcp_index = e_and_si & 0x7fff_ffff; |
| 555 | let ssrc = u32::from_be_bytes([buf[4], buf[5], buf[6], buf[7]]); |
| 556 | |
| 557 | let iv = Aes128CmSha1_80::rtp_iv(*salt, ssrc, srtcp_index as u64); |
| 558 | |
| 559 | // The Encrypted Portion of an SRTCP packet consists of the encryption |
| 560 | // of the RTCP payload of the equivalent compound RTCP packet, from the |
| 561 | // first RTCP packet, i.e., from the ninth (9) octet to the end of the |
| 562 | // compound packet. |
| 563 | let input = &buf[8..idx_start]; |
| 564 | // Allocate buffer with CTR padding (aws-lc-rs requirement) |
| 565 | let mut output = vec![0_u8; input.len() + 8 + CTR_BUFFER_PADDING]; |
| 566 | output[0..8].copy_from_slice(&buf[0..8]); |
| 567 | |
| 568 | if let Err(e) = dec.decrypt(&iv, input, &mut output[8..]) { |
| 569 | warn!("Failed to decrypt SRTCP {}: {}", self.rtcp.profile(), e); |
| 570 | return None; |
| 571 | } |
| 572 | |
| 573 | output.truncate(input.len() + 8); |
| 574 | Some(output) |
| 575 | } |
| 576 | Derived::AeadAes128Gcm { salt, dec, .. } => { |
| 577 | if buf.len() < SRTCP_HEADER_LEN + SRTCP_INDEX_LEN + AeadAes128Gcm::TAG_LEN { |
| 578 | // Too short |
| 579 | return None; |
| 580 | } |
| 581 | |
| 582 | let idx_start = buf.len() - SRTCP_INDEX_LEN; |
| 583 | |
| 584 | // Assume no MKI |
| 585 | let e_and_si = u32::from_be_bytes( |
| 586 | buf[idx_start..buf.len()] |
| 587 | .try_into() |
| 588 | // This is ok because SRTCP_INDEX_LEN is 4 bytes and the buffer is at least |
| 589 | // that long. |
| 590 | .expect("SRTCP_INDEX_LEN to be 4"), |
| 591 | ); |
| 592 | let is_encrypted = e_and_si & 0x8000_0000 > 0; |
| 593 | |
| 594 | // The Encrypted Portion of an SRTCP packet consists of the encryption |
| 595 | // of the RTCP payload of the equivalent compound RTCP packet, from the |
| 596 | // first RTCP packet, i.e., from the ninth (9) octet to the end of the |
| 597 | // compound packet. |
| 598 | let input = if is_encrypted { |
| 599 | &buf[8..idx_start] |
| 600 | } else { |
| 601 | // No, encryption but we still pass the tag down to decrypt so it can verify |
| 602 | // it. |
| 603 | &buf[idx_start - AeadAes128Gcm::TAG_LEN..idx_start] |
| 604 | }; |
| 605 | |
| 606 | // The SRTCP index is a 31-bit counter for the SRTCP packet. |
| 607 | let srtcp_index = e_and_si & 0x7fff_ffff; |
| 608 | let ssrc = u32::from_be_bytes([buf[4], buf[5], buf[6], buf[7]]); |
| 609 | |
| 610 | let iv = AeadAes128Gcm::rtcp_iv(*salt, ssrc, srtcp_index); |
| 611 | // Declared out here for lifetime purposes, only used in the first branch of the if. |
| 612 | let mut encrypted_aad = [0; AeadAes128Gcm::RTCP_AAD_LEN]; |
| 613 | let mut aads: [&[u8]; 2] = [&[], &[]]; |
| 614 | |
| 615 | if is_encrypted { |
| 616 | encrypted_aad[0..8].copy_from_slice(&buf[0..8]); |
| 617 | encrypted_aad[8..12].copy_from_slice(&e_and_si.to_be_bytes()); |
| 618 | |
| 619 | aads[0] = encrypted_aad.as_slice(); |
| 620 | } else { |
| 621 | // The whole packet is AAD |
| 622 | aads[0] = &buf[0..idx_start - AeadAes128Gcm::TAG_LEN]; |
| 623 | aads[1] = &buf[idx_start..]; |
| 624 | }; |
| 625 | |
| 626 | let mut output = vec![0_u8; buf.len() - AeadAes128Gcm::TAG_LEN - SRTCP_INDEX_LEN]; |
| 627 | output[0..8].copy_from_slice(&buf[0..8]); |
| 628 | |
| 629 | let count = match dec.decrypt(&iv, &aads, input, &mut output[8..]) { |
| 630 | Ok(c) => c, |
| 631 | Err(e) => { |
| 632 | warn!("Failed to decrypt SRTCP {}: {}", self.rtcp.profile(), e); |
| 633 | return None; |
| 634 | } |
| 635 | }; |
| 636 | |
| 637 | if is_encrypted { |
| 638 | output.truncate(8 + count); |
| 639 | } else { |
| 640 | // decrypt didn't error, the data is authenticated. |
| 641 | output.copy_from_slice( |
| 642 | &buf[0..buf.len() - SRTCP_INDEX_LEN - AeadAes128Gcm::TAG_LEN], |
| 643 | ) |
| 644 | } |
| 645 | |
| 646 | Some(output) |
| 647 | } |
| 648 | Derived::AeadAes256Gcm { salt, dec, .. } => { |
| 649 | if buf.len() < SRTCP_HEADER_LEN + SRTCP_INDEX_LEN + AeadAes256Gcm::TAG_LEN { |
| 650 | // Too short |
| 651 | return None; |
| 652 | } |
| 653 | |
| 654 | let idx_start = buf.len() - SRTCP_INDEX_LEN; |
| 655 | |
| 656 | // Assume no MKI |
| 657 | let e_and_si = u32::from_be_bytes( |
| 658 | buf[idx_start..buf.len()] |
| 659 | .try_into() |
| 660 | // This is ok because SRTCP_INDEX_LEN is 4 bytes and the buffer is at least |
| 661 | // that long. |
| 662 | .expect("SRTCP_INDEX_LEN to be 4"), |
| 663 | ); |
| 664 | let is_encrypted = e_and_si & 0x8000_0000 > 0; |
| 665 | |
| 666 | // The Encrypted Portion of an SRTCP packet consists of the encryption |
| 667 | // of the RTCP payload of the equivalent compound RTCP packet, from the |
| 668 | // first RTCP packet, i.e., from the ninth (9) octet to the end of the |
| 669 | // compound packet. |
| 670 | let input = if is_encrypted { |
| 671 | &buf[8..idx_start] |
| 672 | } else { |
| 673 | // No, encryption but we still pass the tag down to decrypt so it can verify |
| 674 | // it. |
| 675 | &buf[idx_start - AeadAes256Gcm::TAG_LEN..idx_start] |
| 676 | }; |
| 677 | |
| 678 | // The SRTCP index is a 31-bit counter for the SRTCP packet. |
| 679 | let srtcp_index = e_and_si & 0x7fff_ffff; |
| 680 | let ssrc = u32::from_be_bytes([buf[4], buf[5], buf[6], buf[7]]); |
| 681 | |
| 682 | let iv = AeadAes256Gcm::rtcp_iv(*salt, ssrc, srtcp_index); |
| 683 | // Declared out here for lifetime purposes, only used in the first branch of the if. |
| 684 | let mut encrypted_aad = [0; AeadAes256Gcm::RTCP_AAD_LEN]; |
| 685 | let mut aads: [&[u8]; 2] = [&[], &[]]; |
| 686 | |
| 687 | if is_encrypted { |
| 688 | encrypted_aad[0..8].copy_from_slice(&buf[0..8]); |
| 689 | encrypted_aad[8..12].copy_from_slice(&e_and_si.to_be_bytes()); |
| 690 | |
| 691 | aads[0] = encrypted_aad.as_slice(); |
| 692 | } else { |
| 693 | // The whole packet is AAD |
| 694 | aads[0] = &buf[0..idx_start - AeadAes256Gcm::TAG_LEN]; |
| 695 | aads[1] = &buf[idx_start..]; |
| 696 | }; |
| 697 | |
| 698 | let mut output = vec![0_u8; buf.len() - AeadAes256Gcm::TAG_LEN - SRTCP_INDEX_LEN]; |
| 699 | output[0..8].copy_from_slice(&buf[0..8]); |
| 700 | |
| 701 | let count = match dec.decrypt(&iv, &aads, input, &mut output[8..]) { |
| 702 | Ok(c) => c, |
| 703 | Err(e) => { |
| 704 | warn!("Failed to decrypt SRTCP {}: {}", self.rtcp.profile(), e); |
| 705 | return None; |
| 706 | } |
| 707 | }; |
| 708 | |
| 709 | if is_encrypted { |
| 710 | output.truncate(8 + count); |
| 711 | } else { |
| 712 | // decrypt didn't error, the data is authenticated. |
| 713 | output.copy_from_slice( |
| 714 | &buf[0..buf.len() - SRTCP_INDEX_LEN - AeadAes256Gcm::TAG_LEN], |
| 715 | ) |
| 716 | } |
| 717 | |
| 718 | Some(output) |
| 719 | } |
| 720 | } |
| 721 | } |
| 722 | } |
| 723 | |
| 724 | /// SrtpKeys created from DTLS SrtpKeyMaterial. |
| 725 | #[derive(Debug)] |
| 726 | struct SrtpKey<const ML: usize, const SL: usize> { |
| 727 | master: [u8; ML], |
| 728 | salt: [u8; SL], |
| 729 | } |
| 730 | |
| 731 | impl<const ML: usize, const SL: usize> SrtpKey<ML, SL> { |
| 732 | pub fn new(mat: &KeyingMaterial, left: bool) -> Self { |
| 733 | // layout in SrtpKeyMaterial is [key_input, key_output, salt_input, salt_output] |
| 734 | |
| 735 | // Invariant |
| 736 | assert!( |
| 737 | mat.len() == ML * 2 + SL * 2, |
| 738 | "The KeyingMaterial provided to SrtpKey::new must be ML * 2 + SL * 2 in length" |
| 739 | ); |
| 740 | |
| 741 | // offset 0, offset 1 |
| 742 | let (o0, o1) = if left { (0, 0) } else { (ML, SL) }; |
| 743 | |
| 744 | let mut master = [0; ML]; |
| 745 | let mut salt = [0; SL]; |
| 746 | |
| 747 | master[0..ML].copy_from_slice(&mat[o0..(o0 + ML)]); |
| 748 | salt[0..SL].copy_from_slice(&mat[(ML + ML + o1)..(ML + ML + o1 + SL)]); |
| 749 | |
| 750 | SrtpKey { master, salt } |
| 751 | } |
| 752 | |
| 753 | fn derive(&self, crypto: &dyn SrtpProvider, label: u8, out: &mut [u8]) { |
| 754 | // AES-CM (128 or 256 bits) defined in RFC3711 |
| 755 | assert!(ML == 16 || ML == 32, "Only valid for 128 bit master keys"); |
| 756 | assert!(SL <= 14, "Only valid for 128 bit master keys"); |
| 757 | let mut i = 0; // index in out |
| 758 | |
| 759 | // input layout: [salt[SL] || label, round[2]] (|| is xor 7th byte) |
| 760 | let mut input = [0; 16]; |
| 761 | |
| 762 | input[0..SL].copy_from_slice(&self.salt[..]); |
| 763 | input[7] ^= label; |
| 764 | |
| 765 | let mut buf = [0; 16 + 16]; // output from each AES |
| 766 | let mut round: u16 = 0; // counter for each AES round |
| 767 | |
| 768 | // loop each AES round |
| 769 | loop { |
| 770 | if i == out.len() { |
| 771 | break; |
| 772 | } |
| 773 | |
| 774 | // splice in round at bottom of input |
| 775 | input[14..].copy_from_slice(&round.to_be_bytes()[..]); |
| 776 | |
| 777 | // default key derivation function, which uses AES-128 in Counter Mode |
| 778 | match ML { |
| 779 | 16 => crypto.srtp_aes_128_ecb_round(&self.master, &input[..], &mut buf[..]), |
| 780 | 32 => crypto.srtp_aes_256_ecb_round(&self.master, &input[..], &mut buf[..]), |
| 781 | _ => panic!("Only valid for 128 or 256 bit master keys"), |
| 782 | } |
| 783 | |
| 784 | // Copy to output. Even if we get 32 bytes of output with AES 128 ECB, we |
| 785 | // only use the first 16. That matches the tests in the RFC. |
| 786 | for j in buf.iter().take(16) { |
| 787 | if i == out.len() { |
| 788 | break; |
| 789 | } |
| 790 | out[i] = *j; |
| 791 | i += 1; |
| 792 | } |
| 793 | |
| 794 | round += 1; |
| 795 | } |
| 796 | } |
| 797 | } |
| 798 | |
| 799 | /// Encryption/decryption derived from the SrtpKey. |
| 800 | enum Derived { |
| 801 | Aes128CmSha1_80 { |
| 802 | key: [u8; 20], |
| 803 | salt: [u8; 14], |
| 804 | enc: Box<dyn Aes128CmSha1_80Cipher>, |
| 805 | dec: Box<dyn Aes128CmSha1_80Cipher>, |
| 806 | }, |
| 807 | AeadAes128Gcm { |
| 808 | salt: [u8; 12], |
| 809 | enc: Box<dyn AeadAes128GcmCipher>, |
| 810 | dec: Box<dyn AeadAes128GcmCipher>, |
| 811 | }, |
| 812 | AeadAes256Gcm { |
| 813 | salt: [u8; 12], |
| 814 | enc: Box<dyn AeadAes256GcmCipher>, |
| 815 | dec: Box<dyn AeadAes256GcmCipher>, |
| 816 | }, |
| 817 | } |
| 818 | |
| 819 | impl Derived { |
| 820 | fn aes_128_cm_sha1_80( |
| 821 | crypto: &dyn SrtpProvider, |
| 822 | srtp_key: &SrtpKey<{ Aes128CmSha1_80::KEY_LEN }, { Aes128CmSha1_80::SALT_LEN }>, |
| 823 | ) -> (Self, Self) { |
| 824 | // RTP AES Counter |
| 825 | let mut rtp_aes = [0; Aes128CmSha1_80::KEY_LEN]; |
| 826 | srtp_key.derive(crypto, LABEL_RTP_AES, &mut rtp_aes[..]); |
| 827 | |
| 828 | // RTP SHA1 HMAC |
| 829 | let rtp_hmac = { |
| 830 | let mut hmac = [0; Aes128CmSha1_80::HMAC_KEY_LEN]; |
| 831 | srtp_key.derive(crypto, LABEL_RTP_AUTHENTICATION_KEY, &mut hmac[..]); |
| 832 | hmac |
| 833 | }; |
| 834 | |
| 835 | // RTP IV SALT |
| 836 | let mut rtp_salt = [0; Aes128CmSha1_80::SALT_LEN]; |
| 837 | srtp_key.derive(crypto, LABEL_RTP_SALT, &mut rtp_salt[..]); |
| 838 | |
| 839 | // RTCP AES Counter |
| 840 | let mut rtcp_aes = [0; Aes128CmSha1_80::KEY_LEN]; |
| 841 | srtp_key.derive(crypto, LABEL_RTCP_AES, &mut rtcp_aes[..]); |
| 842 | |
| 843 | // RTCP SHA1 HMAC |
| 844 | let rtcp_hmac = { |
| 845 | let mut hmac = [0; Aes128CmSha1_80::HMAC_KEY_LEN]; |
| 846 | srtp_key.derive(crypto, LABEL_RTCP_AUTHENTICATION_KEY, &mut hmac[..]); |
| 847 | hmac |
| 848 | }; |
| 849 | |
| 850 | // RTCP IV SALT |
| 851 | let mut rtcp_salt = [0; Aes128CmSha1_80::SALT_LEN]; |
| 852 | srtp_key.derive(crypto, LABEL_RTCP_SALT, &mut rtcp_salt[..]); |
| 853 | |
| 854 | let rtp = Derived::Aes128CmSha1_80 { |
| 855 | key: rtp_hmac, |
| 856 | salt: rtp_salt, |
| 857 | enc: crypto.aes_128_cm_sha1_80().create_cipher(rtp_aes, true), |
| 858 | dec: crypto.aes_128_cm_sha1_80().create_cipher(rtp_aes, false), |
| 859 | }; |
| 860 | |
| 861 | let rtcp = Derived::Aes128CmSha1_80 { |
| 862 | key: rtcp_hmac, |
| 863 | salt: rtcp_salt, |
| 864 | enc: crypto.aes_128_cm_sha1_80().create_cipher(rtcp_aes, true), |
| 865 | dec: crypto.aes_128_cm_sha1_80().create_cipher(rtcp_aes, false), |
| 866 | }; |
| 867 | |
| 868 | (rtp, rtcp) |
| 869 | } |
| 870 | |
| 871 | fn aead_aes_128_gcm( |
| 872 | crypto: &dyn SrtpProvider, |
| 873 | srtp_key: &SrtpKey<{ AeadAes128Gcm::KEY_LEN }, { AeadAes128Gcm::SALT_LEN }>, |
| 874 | ) -> (Derived, Derived) { |
| 875 | // RTP session key |
| 876 | let mut rtp_aes = [0; AeadAes128Gcm::KEY_LEN]; |
| 877 | srtp_key.derive(crypto, LABEL_RTP_AES, &mut rtp_aes[..]); |
| 878 | |
| 879 | // RTP session salt |
| 880 | let mut rtp_salt = [0; AeadAes128Gcm::SALT_LEN]; |
| 881 | srtp_key.derive(crypto, LABEL_RTP_SALT, &mut rtp_salt[..]); |
| 882 | |
| 883 | // RTCP session key |
| 884 | let mut rtcp_aes = [0; AeadAes128Gcm::KEY_LEN]; |
| 885 | srtp_key.derive(crypto, LABEL_RTCP_AES, &mut rtcp_aes[..]); |
| 886 | |
| 887 | // RTCP session salt |
| 888 | let mut rtcp_salt = [0; AeadAes128Gcm::SALT_LEN]; |
| 889 | srtp_key.derive(crypto, LABEL_RTCP_SALT, &mut rtcp_salt[..]); |
| 890 | |
| 891 | let rtp = Derived::AeadAes128Gcm { |
| 892 | salt: rtp_salt, |
| 893 | enc: crypto.aead_aes_128_gcm().create_cipher(rtp_aes, true), |
| 894 | dec: crypto.aead_aes_128_gcm().create_cipher(rtp_aes, false), |
| 895 | }; |
| 896 | |
| 897 | let rtcp = Derived::AeadAes128Gcm { |
| 898 | salt: rtcp_salt, |
| 899 | enc: crypto.aead_aes_128_gcm().create_cipher(rtcp_aes, true), |
| 900 | dec: crypto.aead_aes_128_gcm().create_cipher(rtcp_aes, false), |
| 901 | }; |
| 902 | |
| 903 | (rtp, rtcp) |
| 904 | } |
| 905 | |
| 906 | fn aead_aes_256_gcm( |
| 907 | crypto: &dyn SrtpProvider, |
| 908 | srtp_key: &SrtpKey<{ AeadAes256Gcm::KEY_LEN }, { AeadAes256Gcm::SALT_LEN }>, |
| 909 | ) -> (Derived, Derived) { |
| 910 | // RTP session key |
| 911 | let mut rtp_aes = [0; AeadAes256Gcm::KEY_LEN]; |
| 912 | srtp_key.derive(crypto, LABEL_RTP_AES, &mut rtp_aes[..]); |
| 913 | |
| 914 | // RTP session salt |
| 915 | let mut rtp_salt = [0; AeadAes256Gcm::SALT_LEN]; |
| 916 | srtp_key.derive(crypto, LABEL_RTP_SALT, &mut rtp_salt[..]); |
| 917 | |
| 918 | // RTCP session key |
| 919 | let mut rtcp_aes = [0; AeadAes256Gcm::KEY_LEN]; |
| 920 | srtp_key.derive(crypto, LABEL_RTCP_AES, &mut rtcp_aes[..]); |
| 921 | |
| 922 | // RTCP session salt |
| 923 | let mut rtcp_salt = [0; AeadAes256Gcm::SALT_LEN]; |
| 924 | srtp_key.derive(crypto, LABEL_RTCP_SALT, &mut rtcp_salt[..]); |
| 925 | |
| 926 | let rtp = Derived::AeadAes256Gcm { |
| 927 | salt: rtp_salt, |
| 928 | enc: crypto.aead_aes_256_gcm().create_cipher(rtp_aes, true), |
| 929 | dec: crypto.aead_aes_256_gcm().create_cipher(rtp_aes, false), |
| 930 | }; |
| 931 | |
| 932 | let rtcp = Derived::AeadAes256Gcm { |
| 933 | salt: rtcp_salt, |
| 934 | enc: crypto.aead_aes_256_gcm().create_cipher(rtcp_aes, true), |
| 935 | dec: crypto.aead_aes_256_gcm().create_cipher(rtcp_aes, false), |
| 936 | }; |
| 937 | |
| 938 | (rtp, rtcp) |
| 939 | } |
| 940 | |
| 941 | fn profile(&self) -> SrtpProfile { |
| 942 | match self { |
| 943 | Derived::Aes128CmSha1_80 { .. } => SrtpProfile::AES128_CM_SHA1_80, |
| 944 | Derived::AeadAes128Gcm { .. } => SrtpProfile::AEAD_AES_128_GCM, |
| 945 | Derived::AeadAes256Gcm { .. } => SrtpProfile::AEAD_AES_256_GCM, |
| 946 | } |
| 947 | } |
| 948 | } |
| 949 | |
| 950 | impl fmt::Debug for Derived { |
| 951 | fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { |
| 952 | write!(f, "Derived") |
| 953 | } |
| 954 | } |
| 955 | |
| 956 | fn error_details(header: &RtpHeader, srtp_index: u64) -> String { |
| 957 | format!( |
| 958 | "SSRC: {} seq_no: {} pt: {} mid: {:?} rid: {:?} rid_repair: {:?} srtp_index: {}", |
| 959 | header.ssrc, |
| 960 | header.sequence_number, |
| 961 | header.payload_type, |
| 962 | header.ext_vals.mid, |
| 963 | header.ext_vals.rid, |
| 964 | header.ext_vals.rid_repair, |
| 965 | srtp_index |
| 966 | ) |
| 967 | } |
| 968 | |
| 969 | #[cfg(test)] |
| 970 | mod test { |
| 971 | use super::*; |
| 972 | |
| 973 | #[test] |
| 974 | fn derive_key() { |
| 975 | crate::init_crypto_default(); |
| 976 | let provider = crate::crypto::from_feature_flags(); |
| 977 | let crypto = provider.srtp_provider; |
| 978 | |
| 979 | // https://tools.ietf.org/html/rfc3711#appendix-B.3 |
| 980 | // |
| 981 | // Key Derivation Test Vectors. |
| 982 | |
| 983 | let master = [ |
| 984 | 0xE1, 0xF9, 0x7A, 0x0D, 0x3E, 0x01, 0x8B, 0xE0, // |
| 985 | 0xD6, 0x4F, 0xA3, 0x2C, 0x06, 0xDE, 0x41, 0x39, |
| 986 | ]; |
| 987 | |
| 988 | let salt = [ |
| 989 | 0x0E, 0xC6, 0x75, 0xAD, 0x49, 0x8A, 0xFE, // |
| 990 | 0xEB, 0xB6, 0x96, 0x0B, 0x3A, 0xAB, 0xE6, |
| 991 | ]; |
| 992 | |
| 993 | let sk = SrtpKey { master, salt }; |
| 994 | |
| 995 | // aes crypto key |
| 996 | let mut out = [0_u8; 16]; |
| 997 | sk.derive(crypto, 0, &mut out[..]); |
| 998 | |
| 999 | assert_eq!( |
| 1000 | out, |
| 1001 | [ |
| 1002 | 0xC6, 0x1E, 0x7A, 0x93, 0x74, 0x4F, 0x39, 0xEE, // |
| 1003 | 0x10, 0x73, 0x4A, 0xFE, 0x3F, 0xF7, 0xA0, 0x87 |
| 1004 | ] |
| 1005 | ); |
| 1006 | |
| 1007 | // hmac |
| 1008 | let mut out = [0_u8; 20]; |
| 1009 | sk.derive(crypto, 1, &mut out[..]); |
| 1010 | |
| 1011 | assert_eq!( |
| 1012 | out, |
| 1013 | [ |
| 1014 | 0xCE, 0xBE, 0x32, 0x1F, 0x6F, 0xF7, 0x71, 0x6B, // |
| 1015 | 0x6F, 0xD4, 0xAB, 0x49, 0xAF, 0x25, 0x6A, 0x15, // |
| 1016 | 0x6D, 0x38, 0xBA, 0xA4 |
| 1017 | ] |
| 1018 | ); |
| 1019 | |
| 1020 | // salt |
| 1021 | let mut out = [0_u8; 14]; |
| 1022 | sk.derive(crypto, 2, &mut out[..]); |
| 1023 | |
| 1024 | assert_eq!( |
| 1025 | out, |
| 1026 | [ |
| 1027 | 0x30, 0xCB, 0xBC, 0x08, 0x86, 0x3D, 0x8C, // |
| 1028 | 0x85, 0xD4, 0x9D, 0xB3, 0x4A, 0x9A, 0xE1 |
| 1029 | ] |
| 1030 | ); |
| 1031 | } |
| 1032 | |
| 1033 | mod test_aes128_cm_sha1_80 { |
| 1034 | use super::*; |
| 1035 | |
| 1036 | const MAT: [u8; 60] = [ |
| 1037 | 0x2C, 0xB0, 0x23, 0x46, 0xB4, 0x22, 0x76, 0xA6, 0x72, 0xCF, 0xD1, 0x43, 0xAE, 0xC2, |
| 1038 | 0xD5, 0xEE, 0xDD, 0xDE, 0x55, 0xF0, 0xAD, 0x7B, 0xCA, 0xC2, 0x26, 0x66, 0xF1, 0xC6, |
| 1039 | 0x38, 0x61, 0x73, 0xED, 0x6E, 0xB2, 0x5C, 0xB7, 0xD2, 0x6A, 0x61, 0xA1, 0xEE, 0x2C, |
| 1040 | 0x21, 0x0A, 0xDA, 0xE7, 0x60, 0xAA, 0xA2, 0xFD, 0x67, 0xB6, 0x72, 0xC4, 0x1A, 0xED, |
| 1041 | 0x10, 0x5F, 0x9D, 0x36, |
| 1042 | ]; |
| 1043 | |
| 1044 | const SRTCP: &[u8] = &[ |
| 1045 | // header |
| 1046 | 0x80, 0xC8, 0x00, 0x06, // |
| 1047 | // ssrc |
| 1048 | 0x3C, 0xD7, 0xCC, 0x13, // |
| 1049 | // encrypted payload |
| 1050 | 0xB7, 0xC8, 0x31, 0xDC, 0xB7, 0x76, 0xCD, 0x8D, 0xC2, 0x6F, 0xDA, 0x1D, 0x9B, 0xFC, |
| 1051 | 0x8E, 0xE6, 0x58, 0x9A, 0x1A, 0x8A, 0x49, 0x28, 0x9C, 0xAE, 0xB2, 0x64, 0x20, 0x0C, |
| 1052 | 0x37, 0xD2, 0xD0, 0xA4, 0xAF, 0xAC, 0x63, 0x85, 0xFF, 0xC6, 0x0D, 0xEC, 0x7D, 0x06, |
| 1053 | 0xD4, 0x87, 0x3D, 0xD3, 0xA8, 0xCC, // |
| 1054 | // E flag and srtcp index (1) |
| 1055 | 0x80, 0x00, 0x00, 0x01, // |
| 1056 | // hmac |
| 1057 | 0xB7, 0xBB, 0x52, 0x65, 0x21, 0xD1, 0xE7, 0x3C, 0x0F, 0xC0, |
| 1058 | ]; |
| 1059 | |
| 1060 | const DECRYPTED_PAYLOAD: &[u8] = &[ |
| 1061 | 0x80, 0xc8, 0x00, 0x06, 0x3c, 0xd7, 0xcc, 0x13, 0xe2, 0xee, 0x35, 0xc8, 0x60, 0x4e, |
| 1062 | 0x61, 0x8c, 0x26, 0xf3, 0x27, 0x34, 0x00, 0x00, 0x00, 0x43, 0x00, 0x00, 0x14, 0x07, |
| 1063 | 0x81, 0xca, 0x00, 0x06, 0x3c, 0xd7, 0xcc, 0x13, 0x01, 0x10, 0x38, 0x6e, 0x46, 0x75, |
| 1064 | 0x32, 0x68, 0x57, 0x66, 0x72, 0x4d, 0x44, 0x72, 0x47, 0x66, 0x34, 0x6f, 0x00, 0x00, |
| 1065 | ]; |
| 1066 | |
| 1067 | #[test] |
| 1068 | fn unprotect_rtcp() { |
| 1069 | let key_mat = KeyingMaterial::new(&MAT); |
| 1070 | let crypto = crate::crypto::test_default_provider(); |
| 1071 | let mut ctx_rx = |
| 1072 | SrtpContext::new(crypto, SrtpProfile::AES128_CM_SHA1_80, &key_mat, true); |
| 1073 | ctx_rx.srtcp_index = 1; |
| 1074 | |
| 1075 | let decrypted = ctx_rx.unprotect_rtcp(SRTCP).unwrap(); |
| 1076 | |
| 1077 | assert_eq!(ctx_rx.srtcp_index, 1); |
| 1078 | // check srtcp_index in incoming was indeed 1 |
| 1079 | let srtcp_index = SRTCP.len() - Aes128CmSha1_80::HMAC_TAG_LEN - SRTCP_INDEX_LEN; |
| 1080 | let e_and_i = &SRTCP[srtcp_index..(srtcp_index + 4)]; |
| 1081 | assert_eq!(e_and_i, &0x8000_0001_u32.to_be_bytes()); |
| 1082 | assert_eq!(decrypted, DECRYPTED_PAYLOAD); |
| 1083 | |
| 1084 | // Take us back to where we started. |
| 1085 | let encrypted = ctx_rx.protect_rtcp(&decrypted); |
| 1086 | assert_eq!(encrypted, SRTCP); |
| 1087 | } |
| 1088 | } |
| 1089 | |
| 1090 | mod test_aead_aes_128_gcm { |
| 1091 | use crate::crypto::AeadAes128Gcm; |
| 1092 | use crate::rtp_::ExtensionMap; |
| 1093 | |
| 1094 | use super::*; |
| 1095 | |
| 1096 | const TAG_LEN: usize = AeadAes128Gcm::TAG_LEN; |
| 1097 | |
| 1098 | mod rfc7714 { |
| 1099 | // Test vectors from RFC7714 |
| 1100 | |
| 1101 | // Session Key (RTP and RTCP) |
| 1102 | pub(super) const KEY: [u8; 16] = [ |
| 1103 | 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, // |
| 1104 | 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, |
| 1105 | ]; |
| 1106 | |
| 1107 | // Session Salt (RTP and RTCP) |
| 1108 | pub(super) const SALT: [u8; 12] = [ |
| 1109 | 0x51, 0x75, 0x69, 0x64, 0x20, 0x70, 0x72, 0x6f, 0x20, 0x71, 0x75, 0x6f, |
| 1110 | ]; |
| 1111 | |
| 1112 | /// Full plaintext RTP packet. First 12 octets is the header |
| 1113 | pub(super) const PLAINTEXT_RTP_PACKET: &[u8] = &[ |
| 1114 | 0x80, 0x40, 0xf1, 0x7b, 0x80, 0x41, 0xf8, 0xd3, 0x55, 0x01, 0xa0, 0xb2, 0x47, 0x61, |
| 1115 | 0x6c, 0x6c, 0x69, 0x61, 0x20, 0x65, 0x73, 0x74, 0x20, 0x6f, 0x6d, 0x6e, 0x69, 0x73, |
| 1116 | 0x20, 0x64, 0x69, 0x76, 0x69, 0x73, 0x61, 0x20, 0x69, 0x6e, 0x20, 0x70, 0x61, 0x72, |
| 1117 | 0x74, 0x65, 0x73, 0x20, 0x74, 0x72, 0x65, 0x73, |
| 1118 | ]; |
| 1119 | |
| 1120 | /// Full encrypted RTP packet. First 12 octets is the header. |
| 1121 | pub(super) const PROTECTED_RTP_PACKET: &[u8] = &[ |
| 1122 | 0x80, 0x40, 0xf1, 0x7b, 0x80, 0x41, 0xf8, 0xd3, 0x55, 0x01, 0xa0, 0xb2, 0xf2, 0x4d, |
| 1123 | 0xe3, 0xa3, 0xfb, 0x34, 0xde, 0x6c, 0xac, 0xba, 0x86, 0x1c, 0x9d, 0x7e, 0x4b, 0xca, |
| 1124 | 0xbe, 0x63, 0x3b, 0xd5, 0x0d, 0x29, 0x4e, 0x6f, 0x42, 0xa5, 0xf4, 0x7a, 0x51, 0xc7, |
| 1125 | 0xd1, 0x9b, 0x36, 0xde, 0x3a, 0xdf, 0x88, 0x33, 0x89, 0x9d, 0x7f, 0x27, 0xbe, 0xb1, |
| 1126 | 0x6a, 0x91, 0x52, 0xcf, 0x76, 0x5e, 0xe4, 0x39, 0x0c, 0xce, |
| 1127 | ]; |
| 1128 | |
| 1129 | // Full plaintext RTCP packet |
| 1130 | pub(super) const PLAINTEXT_RTCP_PACKET: &[u8] = &[ |
| 1131 | 0x81, 0xc8, 0x00, 0x0d, 0x4d, 0x61, 0x72, 0x73, 0x4e, 0x54, 0x50, 0x31, 0x4e, 0x54, |
| 1132 | 0x50, 0x32, 0x52, 0x54, 0x50, 0x20, 0x00, 0x00, 0x04, 0x2a, 0x00, 0x00, 0xe9, 0x30, |
| 1133 | 0x4c, 0x75, 0x6e, 0x61, 0xde, 0xad, 0xbe, 0xef, 0xde, 0xad, 0xbe, 0xef, 0xde, 0xad, |
| 1134 | 0xbe, 0xef, 0xde, 0xad, 0xbe, 0xef, 0xde, 0xad, 0xbe, 0xef, |
| 1135 | ]; |
| 1136 | |
| 1137 | /// Full encrypted RTCP packet |
| 1138 | pub(super) const PROTECTED_RTCP_PACKET: &[u8] = &[ |
| 1139 | 0x81, 0xc8, 0x00, 0x0d, 0x4d, 0x61, 0x72, 0x73, 0x63, 0xe9, 0x48, 0x85, 0xdc, 0xda, |
| 1140 | 0xb6, 0x7c, 0xa7, 0x27, 0xd7, 0x66, 0x2f, 0x6b, 0x7e, 0x99, 0x7f, 0xf5, 0xc0, 0xf7, |
| 1141 | 0x6c, 0x06, 0xf3, 0x2d, 0xc6, 0x76, 0xa5, 0xf1, 0x73, 0x0d, 0x6f, 0xda, 0x4c, 0xe0, |
| 1142 | 0x9b, 0x46, 0x86, 0x30, 0x3d, 0xed, 0x0b, 0xb9, 0x27, 0x5b, 0xc8, 0x4a, 0xa4, 0x58, |
| 1143 | 0x96, 0xcf, 0x4d, 0x2f, 0xc5, 0xab, 0xf8, 0x72, 0x45, 0xd9, 0xea, 0xde, 0x80, 0x00, |
| 1144 | 0x05, 0xd4, |
| 1145 | ]; |
| 1146 | |
| 1147 | // A RTCP packet that hasn't been encrypted, only authenticated. |
| 1148 | pub(super) const TAGGED_RTCP_PACKET: &[u8] = &[ |
| 1149 | // RTCP Packet |
| 1150 | 0x81, 0xc8, 0x00, 0x0d, 0x4d, 0x61, 0x72, 0x73, 0x4e, 0x54, 0x50, 0x31, 0x4e, 0x54, |
| 1151 | 0x50, 0x32, 0x52, 0x54, 0x50, 0x20, 0x00, 0x00, 0x04, 0x2a, 0x00, 0x00, 0xe9, 0x30, |
| 1152 | 0x4c, 0x75, 0x6e, 0x61, 0xde, 0xad, 0xbe, 0xef, 0xde, 0xad, 0xbe, 0xef, 0xde, 0xad, |
| 1153 | 0xbe, 0xef, 0xde, 0xad, 0xbe, 0xef, 0xde, 0xad, 0xbe, 0xef, // |
| 1154 | // Tag |
| 1155 | 0x84, 0x1d, 0xd9, 0x68, 0x3d, 0xd7, 0x8e, 0xc9, 0x2a, 0xe5, 0x87, 0x90, 0x12, 0x5f, |
| 1156 | 0x62, 0xb3, // |
| 1157 | // SRTCP Index |
| 1158 | 0x00, 0x00, 0x05, 0xd4, |
| 1159 | ]; |
| 1160 | } |
| 1161 | |
| 1162 | #[test] |
| 1163 | fn protect_rtp_rfc_7714_test() { |
| 1164 | let mut context = make_rtp_context(); |
| 1165 | |
| 1166 | let header = |
| 1167 | RtpHeader::parse(&rfc7714::PLAINTEXT_RTP_PACKET[..12], &ExtensionMap::empty()) |
| 1168 | .expect("header to parse"); |
| 1169 | let out = context.protect_rtp(rfc7714::PLAINTEXT_RTP_PACKET, &header, 0); |
| 1170 | |
| 1171 | assert_eq!( |
| 1172 | out, |
| 1173 | rfc7714::PROTECTED_RTP_PACKET, |
| 1174 | "failed to encrypted packet.\n{:02x?}\n{:02x?}", |
| 1175 | out, |
| 1176 | &rfc7714::PLAINTEXT_RTP_PACKET |
| 1177 | ); |
| 1178 | } |
| 1179 | |
| 1180 | #[test] |
| 1181 | fn unprotect_rtp_rfc_7714_test() { |
| 1182 | let mut context = make_rtp_context(); |
| 1183 | let header = |
| 1184 | RtpHeader::parse(&rfc7714::PROTECTED_RTP_PACKET[..12], &ExtensionMap::empty()) |
| 1185 | .expect("header to parse"); |
| 1186 | |
| 1187 | let out = context |
| 1188 | .unprotect_rtp(rfc7714::PROTECTED_RTP_PACKET, &header, 0) |
| 1189 | .expect("decrypt rtp"); |
| 1190 | |
| 1191 | assert_eq!( |
| 1192 | out, |
| 1193 | &rfc7714::PLAINTEXT_RTP_PACKET[12..], |
| 1194 | "failed to decrypt packet.\n{:02x?}\n{:02x?}", |
| 1195 | out, |
| 1196 | &rfc7714::PLAINTEXT_RTP_PACKET |
| 1197 | ); |
| 1198 | } |
| 1199 | |
| 1200 | #[test] |
| 1201 | fn symmetry_rtp_rfc_7714_test() { |
| 1202 | let mut context = make_rtp_context(); |
| 1203 | |
| 1204 | // First we encrypt |
| 1205 | let header = |
| 1206 | RtpHeader::parse(&rfc7714::PLAINTEXT_RTP_PACKET[..12], &ExtensionMap::empty()) |
| 1207 | .expect("header to parse"); |
| 1208 | let encrypted = context.protect_rtp(rfc7714::PLAINTEXT_RTP_PACKET, &header, 0); |
| 1209 | |
| 1210 | // Then we decrypt the resulting cipher text |
| 1211 | let header = RtpHeader::parse(&encrypted[..12], &ExtensionMap::empty()) |
| 1212 | .expect("header to parse"); |
| 1213 | let decrypted = context |
| 1214 | .unprotect_rtp(&encrypted, &header, 0) |
| 1215 | .expect("rtp unprotect"); |
| 1216 | |
| 1217 | // And verify we get the input back. |
| 1218 | assert_eq!(decrypted, &rfc7714::PLAINTEXT_RTP_PACKET[12..]); |
| 1219 | } |
| 1220 | |
| 1221 | #[test] |
| 1222 | fn unprotect_rtp_should_fail_with_broken_tag_data() { |
| 1223 | let mut context = make_rtp_context(); |
| 1224 | |
| 1225 | let header_buf = { |
| 1226 | let mut buf = rfc7714::PROTECTED_RTP_PACKET[..12].to_vec(); |
| 1227 | // Mess with part of the sequence number, since this makes up part of the |
| 1228 | // authenticated additional data(AAD) the resulting authenticity tag should not |
| 1229 | // match. |
| 1230 | buf[3] ^= 0xFF; |
| 1231 | |
| 1232 | buf |
| 1233 | }; |
| 1234 | |
| 1235 | let header = |
| 1236 | RtpHeader::parse(&header_buf, &ExtensionMap::empty()).expect("header to parse"); |
| 1237 | |
| 1238 | let result = context.unprotect_rtp(rfc7714::PROTECTED_RTP_PACKET, &header, 0); |
| 1239 | assert!( |
| 1240 | result.is_none(), |
| 1241 | "Should fail to decrypt a SRTP packet that has mismatched \ |
| 1242 | authenicated additional data" |
| 1243 | ); |
| 1244 | } |
| 1245 | |
| 1246 | #[test] |
| 1247 | fn unprotect_rtp_should_fail_with_broken_null_tag() { |
| 1248 | let mut context = make_rtp_context(); |
| 1249 | |
| 1250 | let input = { |
| 1251 | let mut input = rfc7714::PROTECTED_RTP_PACKET.to_vec(); |
| 1252 | let len = input.len(); |
| 1253 | input[len - TAG_LEN..].copy_from_slice(&[0; TAG_LEN]); |
| 1254 | |
| 1255 | input |
| 1256 | }; |
| 1257 | |
| 1258 | let header = |
| 1259 | RtpHeader::parse(&input[..12], &ExtensionMap::empty()).expect("header to parse"); |
| 1260 | |
| 1261 | let result = context.unprotect_rtp(&input, &header, 0); |
| 1262 | assert!( |
| 1263 | result.is_none(), |
| 1264 | "Should fail to decrypt a SRTP packet with null tag" |
| 1265 | ); |
| 1266 | } |
| 1267 | |
| 1268 | #[test] |
| 1269 | fn protect_rtcp_rfc_7714_test() { |
| 1270 | let mut context = make_rtcp_context(); |
| 1271 | |
| 1272 | let out = context.protect_rtcp(rfc7714::PLAINTEXT_RTCP_PACKET); |
| 1273 | |
| 1274 | assert!( |
| 1275 | out == rfc7714::PROTECTED_RTCP_PACKET, |
| 1276 | "Expected encrypted and tagged RTCP packet:\n{:02x?}\nGot:\n{:02x?}", |
| 1277 | rfc7714::PROTECTED_RTCP_PACKET, |
| 1278 | out |
| 1279 | ); |
| 1280 | } |
| 1281 | |
| 1282 | #[test] |
| 1283 | fn unprotect_rtcp_rfc_auth_only_7714_test() { |
| 1284 | let mut context = make_rtcp_context(); |
| 1285 | |
| 1286 | let out = context |
| 1287 | .unprotect_rtcp(rfc7714::TAGGED_RTCP_PACKET) |
| 1288 | .expect("Unprotect RTCP"); |
| 1289 | |
| 1290 | assert_eq!(out, rfc7714::PLAINTEXT_RTCP_PACKET); |
| 1291 | } |
| 1292 | |
| 1293 | fn make_rtp_context() -> SrtpContext { |
| 1294 | crate::init_crypto_default(); |
| 1295 | SrtpContext::new_aead_aes_128_gcm( |
| 1296 | rfc7714::KEY, |
| 1297 | rfc7714::SALT, |
| 1298 | rfc7714::KEY, |
| 1299 | rfc7714::SALT, |
| 1300 | 0, |
| 1301 | ) |
| 1302 | } |
| 1303 | |
| 1304 | fn make_rtcp_context() -> SrtpContext { |
| 1305 | crate::init_crypto_default(); |
| 1306 | SrtpContext::new_aead_aes_128_gcm( |
| 1307 | rfc7714::KEY, |
| 1308 | rfc7714::SALT, |
| 1309 | rfc7714::KEY, |
| 1310 | rfc7714::SALT, |
| 1311 | 0x000005d4, |
| 1312 | ) |
| 1313 | } |
| 1314 | } |
| 1315 | |
| 1316 | mod test_aead_aes_256_gcm { |
| 1317 | use crate::crypto::AeadAes256Gcm; |
| 1318 | use crate::rtp_::ExtensionMap; |
| 1319 | |
| 1320 | use super::*; |
| 1321 | |
| 1322 | const TAG_LEN: usize = AeadAes256Gcm::TAG_LEN; |
| 1323 | |
| 1324 | mod rfc7714 { |
| 1325 | // Test vectors from RFC7714 |
| 1326 | |
| 1327 | // Session Key (RTP and RTCP) |
| 1328 | pub(super) const KEY: [u8; 32] = [ |
| 1329 | 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, // |
| 1330 | 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, // |
| 1331 | 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, // |
| 1332 | 0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, |
| 1333 | ]; |
| 1334 | |
| 1335 | // Session Salt (RTP and RTCP) |
| 1336 | pub(super) const SALT: [u8; 12] = [ |
| 1337 | 0x51, 0x75, 0x69, 0x64, 0x20, 0x70, 0x72, 0x6f, 0x20, 0x71, 0x75, 0x6f, |
| 1338 | ]; |
| 1339 | |
| 1340 | /// Full plaintext RTP packet. First 12 octets is the header |
| 1341 | pub(super) const PLAINTEXT_RTP_PACKET: &[u8] = &[ |
| 1342 | 0x80, 0x40, 0xf1, 0x7b, 0x80, 0x41, 0xf8, 0xd3, 0x55, 0x01, 0xa0, 0xb2, 0x47, 0x61, |
| 1343 | 0x6c, 0x6c, 0x69, 0x61, 0x20, 0x65, 0x73, 0x74, 0x20, 0x6f, 0x6d, 0x6e, 0x69, 0x73, |
| 1344 | 0x20, 0x64, 0x69, 0x76, 0x69, 0x73, 0x61, 0x20, 0x69, 0x6e, 0x20, 0x70, 0x61, 0x72, |
| 1345 | 0x74, 0x65, 0x73, 0x20, 0x74, 0x72, 0x65, 0x73, |
| 1346 | ]; |
| 1347 | |
| 1348 | /// Full encrypted RTP packet. First 12 octets is the header. |
| 1349 | pub(super) const PROTECTED_RTP_PACKET: &[u8] = &[ |
| 1350 | 0x80, 0x40, 0xf1, 0x7b, 0x80, 0x41, 0xf8, 0xd3, 0x55, 0x01, 0xa0, 0xb2, 0x32, 0xb1, |
| 1351 | 0xde, 0x78, 0xa8, 0x22, 0xfe, 0x12, 0xef, 0x9f, 0x78, 0xfa, 0x33, 0x2e, 0x33, 0xaa, |
| 1352 | 0xb1, 0x80, 0x12, 0x38, 0x9a, 0x58, 0xe2, 0xf3, 0xb5, 0x0b, 0x2a, 0x02, 0x76, 0xff, |
| 1353 | 0xae, 0x0f, 0x1b, 0xa6, 0x37, 0x99, 0xb8, 0x7b, 0x7a, 0xa3, 0xdb, 0x36, 0xdf, 0xff, |
| 1354 | 0xd6, 0xb0, 0xf9, 0xbb, 0x78, 0x78, 0xd7, 0xa7, 0x6c, 0x13, |
| 1355 | ]; |
| 1356 | |
| 1357 | // Full plaintext RTCP packet |
| 1358 | pub(super) const PLAINTEXT_RTCP_PACKET: &[u8] = &[ |
| 1359 | 0x81, 0xc8, 0x00, 0x0d, 0x4d, 0x61, 0x72, 0x73, 0x4e, 0x54, 0x50, 0x31, 0x4e, 0x54, |
| 1360 | 0x50, 0x32, 0x52, 0x54, 0x50, 0x20, 0x00, 0x00, 0x04, 0x2a, 0x00, 0x00, 0xe9, 0x30, |
| 1361 | 0x4c, 0x75, 0x6e, 0x61, 0xde, 0xad, 0xbe, 0xef, 0xde, 0xad, 0xbe, 0xef, 0xde, 0xad, |
| 1362 | 0xbe, 0xef, 0xde, 0xad, 0xbe, 0xef, 0xde, 0xad, 0xbe, 0xef, |
| 1363 | ]; |
| 1364 | |
| 1365 | /// Full encrypted RTCP packet |
| 1366 | pub(super) const PROTECTED_RTCP_PACKET: &[u8] = &[ |
| 1367 | 0x81, 0xc8, 0x00, 0x0d, 0x4d, 0x61, 0x72, 0x73, 0xd5, 0x0a, 0xe4, 0xd1, 0xf5, 0xce, |
| 1368 | 0x5d, 0x30, 0x4b, 0xa2, 0x97, 0xe4, 0x7d, 0x47, 0x0c, 0x28, 0x2c, 0x3e, 0xce, 0x5d, |
| 1369 | 0xbf, 0xfe, 0x0a, 0x50, 0xa2, 0xea, 0xa5, 0xc1, 0x11, 0x05, 0x55, 0xbe, 0x84, 0x15, |
| 1370 | 0xf6, 0x58, 0xc6, 0x1d, 0xe0, 0x47, 0x6f, 0x1b, 0x6f, 0xad, 0x1d, 0x1e, 0xb3, 0x0c, |
| 1371 | 0x44, 0x46, 0x83, 0x9f, 0x57, 0xff, 0x6f, 0x6c, 0xb2, 0x6a, 0xc3, 0xbe, 0x80, 0x00, |
| 1372 | 0x05, 0xd4, |
| 1373 | ]; |
| 1374 | |
| 1375 | // A RTCP packet that hasn't been encrypted, only authenticated. |
| 1376 | pub(super) const TAGGED_RTCP_PACKET: &[u8] = &[ |
| 1377 | // RTCP Packet |
| 1378 | 0x81, 0xc8, 0x00, 0x0d, 0x4d, 0x61, 0x72, 0x73, 0x4e, 0x54, 0x50, 0x31, 0x4e, 0x54, |
| 1379 | 0x50, 0x32, 0x52, 0x54, 0x50, 0x20, 0x00, 0x00, 0x04, 0x2a, 0x00, 0x00, 0xe9, 0x30, |
| 1380 | 0x4c, 0x75, 0x6e, 0x61, 0xde, 0xad, 0xbe, 0xef, 0xde, 0xad, 0xbe, 0xef, 0xde, 0xad, |
| 1381 | 0xbe, 0xef, 0xde, 0xad, 0xbe, 0xef, 0xde, 0xad, 0xbe, 0xef, // |
| 1382 | // Tag |
| 1383 | 0x91, 0xdb, 0x4a, 0xfb, 0xfe, 0xee, 0x5a, 0x97, 0x8f, 0xab, 0x43, 0x93, 0xed, 0x26, |
| 1384 | 0x15, 0xfe, // |
| 1385 | // SRTCP Index |
| 1386 | 0x00, 0x00, 0x05, 0xd4, |
| 1387 | ]; |
| 1388 | } |
| 1389 | |
| 1390 | #[test] |
| 1391 | fn protect_rtp_rfc_7714_test() { |
| 1392 | let mut context = make_rtp_context(); |
| 1393 | |
| 1394 | let header = |
| 1395 | RtpHeader::parse(&rfc7714::PLAINTEXT_RTP_PACKET[..12], &ExtensionMap::empty()) |
| 1396 | .expect("header to parse"); |
| 1397 | let out = context.protect_rtp(rfc7714::PLAINTEXT_RTP_PACKET, &header, 0); |
| 1398 | |
| 1399 | assert_eq!( |
| 1400 | out, |
| 1401 | rfc7714::PROTECTED_RTP_PACKET, |
| 1402 | "failed to encrypted packet.\n{:02x?}\n{:02x?}", |
| 1403 | out, |
| 1404 | &rfc7714::PLAINTEXT_RTP_PACKET |
| 1405 | ); |
| 1406 | } |
| 1407 | |
| 1408 | #[test] |
| 1409 | fn unprotect_rtp_rfc_7714_test() { |
| 1410 | let mut context = make_rtp_context(); |
| 1411 | let header = |
| 1412 | RtpHeader::parse(&rfc7714::PROTECTED_RTP_PACKET[..12], &ExtensionMap::empty()) |
| 1413 | .expect("header to parse"); |
| 1414 | |
| 1415 | let out = context |
| 1416 | .unprotect_rtp(rfc7714::PROTECTED_RTP_PACKET, &header, 0) |
| 1417 | .expect("decrypt rtp"); |
| 1418 | |
| 1419 | assert_eq!( |
| 1420 | out, |
| 1421 | &rfc7714::PLAINTEXT_RTP_PACKET[12..], |
| 1422 | "failed to decrypt packet.\n{:02x?}\n{:02x?}", |
| 1423 | out, |
| 1424 | &rfc7714::PLAINTEXT_RTP_PACKET |
| 1425 | ); |
| 1426 | } |
| 1427 | |
| 1428 | #[test] |
| 1429 | fn symmetry_rtp_rfc_7714_test() { |
| 1430 | let mut context = make_rtp_context(); |
| 1431 | |
| 1432 | // First we encrypt |
| 1433 | let header = |
| 1434 | RtpHeader::parse(&rfc7714::PLAINTEXT_RTP_PACKET[..12], &ExtensionMap::empty()) |
| 1435 | .expect("header to parse"); |
| 1436 | let encrypted = context.protect_rtp(rfc7714::PLAINTEXT_RTP_PACKET, &header, 0); |
| 1437 | |
| 1438 | // Then we decrypt the resulting cipher text |
| 1439 | let header = RtpHeader::parse(&encrypted[..12], &ExtensionMap::empty()) |
| 1440 | .expect("header to parse"); |
| 1441 | let decrypted = context |
| 1442 | .unprotect_rtp(&encrypted, &header, 0) |
| 1443 | .expect("rtp unprotect"); |
| 1444 | |
| 1445 | // And verify we get the input back. |
| 1446 | assert_eq!(decrypted, &rfc7714::PLAINTEXT_RTP_PACKET[12..]); |
| 1447 | } |
| 1448 | |
| 1449 | #[test] |
| 1450 | fn unprotect_rtp_should_fail_with_broken_tag_data() { |
| 1451 | let mut context = make_rtp_context(); |
| 1452 | |
| 1453 | let header_buf = { |
| 1454 | let mut buf = rfc7714::PROTECTED_RTP_PACKET[..12].to_vec(); |
| 1455 | // Mess with part of the sequence number, since this makes up part of the |
| 1456 | // authenticated additional data(AAD) the resulting authenticity tag should not |
| 1457 | // match. |
| 1458 | buf[3] ^= 0xFF; |
| 1459 | |
| 1460 | buf |
| 1461 | }; |
| 1462 | |
| 1463 | let header = |
| 1464 | RtpHeader::parse(&header_buf, &ExtensionMap::empty()).expect("header to parse"); |
| 1465 | |
| 1466 | let result = context.unprotect_rtp(rfc7714::PROTECTED_RTP_PACKET, &header, 0); |
| 1467 | assert!( |
| 1468 | result.is_none(), |
| 1469 | "Should fail to decrypt a SRTP packet that has mismatched \ |
| 1470 | authenicated additional data" |
| 1471 | ); |
| 1472 | } |
| 1473 | |
| 1474 | #[test] |
| 1475 | fn unprotect_rtp_should_fail_with_broken_null_tag() { |
| 1476 | let mut context = make_rtp_context(); |
| 1477 | |
| 1478 | let input = { |
| 1479 | let mut input = rfc7714::PROTECTED_RTP_PACKET.to_vec(); |
| 1480 | let len = input.len(); |
| 1481 | input[len - TAG_LEN..].copy_from_slice(&[0; TAG_LEN]); |
| 1482 | |
| 1483 | input |
| 1484 | }; |
| 1485 | |
| 1486 | let header = |
| 1487 | RtpHeader::parse(&input[..12], &ExtensionMap::empty()).expect("header to parse"); |
| 1488 | |
| 1489 | let result = context.unprotect_rtp(&input, &header, 0); |
| 1490 | assert!( |
| 1491 | result.is_none(), |
| 1492 | "Should fail to decrypt a SRTP packet with null tag" |
| 1493 | ); |
| 1494 | } |
| 1495 | |
| 1496 | #[test] |
| 1497 | fn protect_rtcp_rfc_7714_test() { |
| 1498 | let mut context = make_rtcp_context(); |
| 1499 | |
| 1500 | let out = context.protect_rtcp(rfc7714::PLAINTEXT_RTCP_PACKET); |
| 1501 | |
| 1502 | assert!( |
| 1503 | out == rfc7714::PROTECTED_RTCP_PACKET, |
| 1504 | "Expected encrypted and tagged RTCP packet:\n{:02x?}\nGot:\n{:02x?}", |
| 1505 | rfc7714::PROTECTED_RTCP_PACKET, |
| 1506 | out |
| 1507 | ); |
| 1508 | } |
| 1509 | |
| 1510 | #[test] |
| 1511 | fn unprotect_rtcp_rfc_auth_only_7714_test() { |
| 1512 | let mut context = make_rtcp_context(); |
| 1513 | |
| 1514 | let out = context |
| 1515 | .unprotect_rtcp(rfc7714::TAGGED_RTCP_PACKET) |
| 1516 | .expect("Unprotect RTCP"); |
| 1517 | |
| 1518 | assert_eq!(out, rfc7714::PLAINTEXT_RTCP_PACKET); |
| 1519 | } |
| 1520 | |
| 1521 | fn make_rtp_context() -> SrtpContext { |
| 1522 | crate::init_crypto_default(); |
| 1523 | SrtpContext::new_aead_aes_256_gcm( |
| 1524 | rfc7714::KEY, |
| 1525 | rfc7714::SALT, |
| 1526 | rfc7714::KEY, |
| 1527 | rfc7714::SALT, |
| 1528 | 0, |
| 1529 | ) |
| 1530 | } |
| 1531 | |
| 1532 | fn make_rtcp_context() -> SrtpContext { |
| 1533 | crate::init_crypto_default(); |
| 1534 | SrtpContext::new_aead_aes_256_gcm( |
| 1535 | rfc7714::KEY, |
| 1536 | rfc7714::SALT, |
| 1537 | rfc7714::KEY, |
| 1538 | rfc7714::SALT, |
| 1539 | 0x000005d4, |
| 1540 | ) |
| 1541 | } |
| 1542 | } |
| 1543 | } |