1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * algif_hash: User-space interface for hash algorithms 4 * 5 * This file provides the user-space API for hash algorithms. 6 * 7 * Copyright (c) 2010 Herbert Xu <herbert@gondor.apana.org.au> 8 */ 9 10 #include <crypto/hash.h> 11 #include <crypto/if_alg.h> 12 #include <linux/init.h> 13 #include <linux/kernel.h> 14 #include <linux/mm.h> 15 #include <linux/module.h> 16 #include <linux/net.h> 17 #include <net/sock.h> 18 19 struct hash_ctx { 20 struct af_alg_sgl sgl; 21 22 u8 *result; 23 24 struct crypto_wait wait; 25 26 unsigned int len; 27 bool more; 28 29 struct ahash_request req; 30 }; 31 32 static int hash_alloc_result(struct sock *sk, struct hash_ctx *ctx) 33 { 34 unsigned ds; 35 36 if (ctx->result) 37 return 0; 38 39 ds = crypto_ahash_digestsize(crypto_ahash_reqtfm(&ctx->req)); 40 41 ctx->result = sock_kmalloc(sk, ds, GFP_KERNEL); 42 if (!ctx->result) 43 return -ENOMEM; 44 45 memset(ctx->result, 0, ds); 46 47 return 0; 48 } 49 50 static void hash_free_result(struct sock *sk, struct hash_ctx *ctx) 51 { 52 unsigned ds; 53 54 if (!ctx->result) 55 return; 56 57 ds = crypto_ahash_digestsize(crypto_ahash_reqtfm(&ctx->req)); 58 59 sock_kzfree_s(sk, ctx->result, ds); 60 ctx->result = NULL; 61 } 62 63 static int hash_sendmsg(struct socket *sock, struct msghdr *msg, 64 size_t ignored) 65 { 66 struct sock *sk = sock->sk; 67 struct alg_sock *ask = alg_sk(sk); 68 struct hash_ctx *ctx = ask->private; 69 ssize_t copied = 0; 70 size_t len, max_pages, npages; 71 bool continuing = ctx->more, need_init = false; 72 int err; 73 74 max_pages = min_t(size_t, ALG_MAX_PAGES, 75 DIV_ROUND_UP(sk->sk_sndbuf, PAGE_SIZE)); 76 77 lock_sock(sk); 78 if (!continuing) { 79 if ((msg->msg_flags & MSG_MORE)) 80 hash_free_result(sk, ctx); 81 need_init = true; 82 } 83 84 ctx->more = false; 85 86 while (msg_data_left(msg)) { 87 ctx->sgl.sgt.sgl = ctx->sgl.sgl; 88 ctx->sgl.sgt.nents = 0; 89 ctx->sgl.sgt.orig_nents = 0; 90 91 err = -EIO; 92 npages = iov_iter_npages(&msg->msg_iter, max_pages); 93 if (npages == 0) 94 goto unlock_free; 95 96 if (npages > ARRAY_SIZE(ctx->sgl.sgl)) { 97 err = -ENOMEM; 98 ctx->sgl.sgt.sgl = 99 kvmalloc(array_size(npages, 100 sizeof(*ctx->sgl.sgt.sgl)), 101 GFP_KERNEL); 102 if (!ctx->sgl.sgt.sgl) 103 goto unlock_free; 104 } 105 sg_init_table(ctx->sgl.sgl, npages); 106 107 ctx->sgl.need_unpin = iov_iter_extract_will_pin(&msg->msg_iter); 108 109 err = extract_iter_to_sg(&msg->msg_iter, LONG_MAX, 110 &ctx->sgl.sgt, npages, 0); 111 if (err < 0) 112 goto unlock_free; 113 len = err; 114 sg_mark_end(ctx->sgl.sgt.sgl + ctx->sgl.sgt.nents - 1); 115 116 if (!msg_data_left(msg)) { 117 err = hash_alloc_result(sk, ctx); 118 if (err) 119 goto unlock_free; 120 } 121 122 ahash_request_set_crypt(&ctx->req, ctx->sgl.sgt.sgl, 123 ctx->result, len); 124 125 if (!msg_data_left(msg) && !continuing && 126 !(msg->msg_flags & MSG_MORE)) { 127 err = crypto_ahash_digest(&ctx->req); 128 } else { 129 if (need_init) { 130 err = crypto_wait_req( 131 crypto_ahash_init(&ctx->req), 132 &ctx->wait); 133 if (err) 134 goto unlock_free; 135 need_init = false; 136 } 137 138 if (msg_data_left(msg) || (msg->msg_flags & MSG_MORE)) 139 err = crypto_ahash_update(&ctx->req); 140 else 141 err = crypto_ahash_finup(&ctx->req); 142 continuing = true; 143 } 144 145 err = crypto_wait_req(err, &ctx->wait); 146 if (err) 147 goto unlock_free; 148 149 copied += len; 150 af_alg_free_sg(&ctx->sgl); 151 } 152 153 ctx->more = msg->msg_flags & MSG_MORE; 154 err = 0; 155 unlock: 156 release_sock(sk); 157 return copied ?: err; 158 159 unlock_free: 160 af_alg_free_sg(&ctx->sgl); 161 goto unlock; 162 } 163 164 static int hash_recvmsg(struct socket *sock, struct msghdr *msg, size_t len, 165 int flags) 166 { 167 struct sock *sk = sock->sk; 168 struct alg_sock *ask = alg_sk(sk); 169 struct hash_ctx *ctx = ask->private; 170 unsigned ds = crypto_ahash_digestsize(crypto_ahash_reqtfm(&ctx->req)); 171 bool result; 172 int err; 173 174 if (len > ds) 175 len = ds; 176 else if (len < ds) 177 msg->msg_flags |= MSG_TRUNC; 178 179 lock_sock(sk); 180 result = ctx->result; 181 err = hash_alloc_result(sk, ctx); 182 if (err) 183 goto unlock; 184 185 ahash_request_set_crypt(&ctx->req, NULL, ctx->result, 0); 186 187 if (!result && !ctx->more) { 188 err = crypto_wait_req(crypto_ahash_init(&ctx->req), 189 &ctx->wait); 190 if (err) 191 goto unlock; 192 } 193 194 if (!result || ctx->more) { 195 ctx->more = false; 196 err = crypto_wait_req(crypto_ahash_final(&ctx->req), 197 &ctx->wait); 198 if (err) 199 goto unlock; 200 } 201 202 err = memcpy_to_msg(msg, ctx->result, len); 203 204 unlock: 205 hash_free_result(sk, ctx); 206 release_sock(sk); 207 208 return err ?: len; 209 } 210 211 static int hash_accept(struct socket *sock, struct socket *newsock, int flags, 212 bool kern) 213 { 214 struct sock *sk = sock->sk; 215 struct alg_sock *ask = alg_sk(sk); 216 struct hash_ctx *ctx = ask->private; 217 struct ahash_request *req = &ctx->req; 218 struct crypto_ahash *tfm; 219 struct sock *sk2; 220 struct alg_sock *ask2; 221 struct hash_ctx *ctx2; 222 char *state; 223 bool more; 224 int err; 225 226 tfm = crypto_ahash_reqtfm(req); 227 state = kmalloc(crypto_ahash_statesize(tfm), GFP_KERNEL); 228 err = -ENOMEM; 229 if (!state) 230 goto out; 231 232 lock_sock(sk); 233 more = ctx->more; 234 err = more ? crypto_ahash_export(req, state) : 0; 235 release_sock(sk); 236 237 if (err) 238 goto out_free_state; 239 240 err = af_alg_accept(ask->parent, newsock, kern); 241 if (err) 242 goto out_free_state; 243 244 sk2 = newsock->sk; 245 ask2 = alg_sk(sk2); 246 ctx2 = ask2->private; 247 ctx2->more = more; 248 249 if (!more) 250 goto out_free_state; 251 252 err = crypto_ahash_import(&ctx2->req, state); 253 if (err) { 254 sock_orphan(sk2); 255 sock_put(sk2); 256 } 257 258 out_free_state: 259 kfree_sensitive(state); 260 261 out: 262 return err; 263 } 264 265 static struct proto_ops algif_hash_ops = { 266 .family = PF_ALG, 267 268 .connect = sock_no_connect, 269 .socketpair = sock_no_socketpair, 270 .getname = sock_no_getname, 271 .ioctl = sock_no_ioctl, 272 .listen = sock_no_listen, 273 .shutdown = sock_no_shutdown, 274 .mmap = sock_no_mmap, 275 .bind = sock_no_bind, 276 277 .release = af_alg_release, 278 .sendmsg = hash_sendmsg, 279 .recvmsg = hash_recvmsg, 280 .accept = hash_accept, 281 }; 282 283 static int hash_check_key(struct socket *sock) 284 { 285 int err = 0; 286 struct sock *psk; 287 struct alg_sock *pask; 288 struct crypto_ahash *tfm; 289 struct sock *sk = sock->sk; 290 struct alg_sock *ask = alg_sk(sk); 291 292 lock_sock(sk); 293 if (!atomic_read(&ask->nokey_refcnt)) 294 goto unlock_child; 295 296 psk = ask->parent; 297 pask = alg_sk(ask->parent); 298 tfm = pask->private; 299 300 err = -ENOKEY; 301 lock_sock_nested(psk, SINGLE_DEPTH_NESTING); 302 if (crypto_ahash_get_flags(tfm) & CRYPTO_TFM_NEED_KEY) 303 goto unlock; 304 305 atomic_dec(&pask->nokey_refcnt); 306 atomic_set(&ask->nokey_refcnt, 0); 307 308 err = 0; 309 310 unlock: 311 release_sock(psk); 312 unlock_child: 313 release_sock(sk); 314 315 return err; 316 } 317 318 static int hash_sendmsg_nokey(struct socket *sock, struct msghdr *msg, 319 size_t size) 320 { 321 int err; 322 323 err = hash_check_key(sock); 324 if (err) 325 return err; 326 327 return hash_sendmsg(sock, msg, size); 328 } 329 330 static int hash_recvmsg_nokey(struct socket *sock, struct msghdr *msg, 331 size_t ignored, int flags) 332 { 333 int err; 334 335 err = hash_check_key(sock); 336 if (err) 337 return err; 338 339 return hash_recvmsg(sock, msg, ignored, flags); 340 } 341 342 static int hash_accept_nokey(struct socket *sock, struct socket *newsock, 343 int flags, bool kern) 344 { 345 int err; 346 347 err = hash_check_key(sock); 348 if (err) 349 return err; 350 351 return hash_accept(sock, newsock, flags, kern); 352 } 353 354 static struct proto_ops algif_hash_ops_nokey = { 355 .family = PF_ALG, 356 357 .connect = sock_no_connect, 358 .socketpair = sock_no_socketpair, 359 .getname = sock_no_getname, 360 .ioctl = sock_no_ioctl, 361 .listen = sock_no_listen, 362 .shutdown = sock_no_shutdown, 363 .mmap = sock_no_mmap, 364 .bind = sock_no_bind, 365 366 .release = af_alg_release, 367 .sendmsg = hash_sendmsg_nokey, 368 .recvmsg = hash_recvmsg_nokey, 369 .accept = hash_accept_nokey, 370 }; 371 372 static void *hash_bind(const char *name, u32 type, u32 mask) 373 { 374 return crypto_alloc_ahash(name, type, mask); 375 } 376 377 static void hash_release(void *private) 378 { 379 crypto_free_ahash(private); 380 } 381 382 static int hash_setkey(void *private, const u8 *key, unsigned int keylen) 383 { 384 return crypto_ahash_setkey(private, key, keylen); 385 } 386 387 static void hash_sock_destruct(struct sock *sk) 388 { 389 struct alg_sock *ask = alg_sk(sk); 390 struct hash_ctx *ctx = ask->private; 391 392 hash_free_result(sk, ctx); 393 sock_kfree_s(sk, ctx, ctx->len); 394 af_alg_release_parent(sk); 395 } 396 397 static int hash_accept_parent_nokey(void *private, struct sock *sk) 398 { 399 struct crypto_ahash *tfm = private; 400 struct alg_sock *ask = alg_sk(sk); 401 struct hash_ctx *ctx; 402 unsigned int len = sizeof(*ctx) + crypto_ahash_reqsize(tfm); 403 404 ctx = sock_kmalloc(sk, len, GFP_KERNEL); 405 if (!ctx) 406 return -ENOMEM; 407 408 ctx->result = NULL; 409 ctx->len = len; 410 ctx->more = false; 411 crypto_init_wait(&ctx->wait); 412 413 ask->private = ctx; 414 415 ahash_request_set_tfm(&ctx->req, tfm); 416 ahash_request_set_callback(&ctx->req, CRYPTO_TFM_REQ_MAY_BACKLOG, 417 crypto_req_done, &ctx->wait); 418 419 sk->sk_destruct = hash_sock_destruct; 420 421 return 0; 422 } 423 424 static int hash_accept_parent(void *private, struct sock *sk) 425 { 426 struct crypto_ahash *tfm = private; 427 428 if (crypto_ahash_get_flags(tfm) & CRYPTO_TFM_NEED_KEY) 429 return -ENOKEY; 430 431 return hash_accept_parent_nokey(private, sk); 432 } 433 434 static const struct af_alg_type algif_type_hash = { 435 .bind = hash_bind, 436 .release = hash_release, 437 .setkey = hash_setkey, 438 .accept = hash_accept_parent, 439 .accept_nokey = hash_accept_parent_nokey, 440 .ops = &algif_hash_ops, 441 .ops_nokey = &algif_hash_ops_nokey, 442 .name = "hash", 443 .owner = THIS_MODULE 444 }; 445 446 static int __init algif_hash_init(void) 447 { 448 return af_alg_register_type(&algif_type_hash); 449 } 450 451 static void __exit algif_hash_exit(void) 452 { 453 int err = af_alg_unregister_type(&algif_type_hash); 454 BUG_ON(err); 455 } 456 457 module_init(algif_hash_init); 458 module_exit(algif_hash_exit); 459 MODULE_LICENSE("GPL"); 460