| 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
| 2 | /* |
| 3 | * algif_skcipher: User-space interface for skcipher algorithms |
| 4 | * |
| 5 | * This file provides the user-space API for symmetric key ciphers. |
| 6 | * |
| 7 | * Copyright (c) 2010 Herbert Xu <herbert@gondor.apana.org.au> |
| 8 | * |
| 9 | * The following concept of the memory management is used: |
| 10 | * |
| 11 | * The kernel maintains two SGLs, the TX SGL and the RX SGL. The TX SGL is |
| 12 | * filled by user space with the data submitted via sendpage/sendmsg. Filling |
| 13 | * up the TX SGL does not cause a crypto operation -- the data will only be |
| 14 | * tracked by the kernel. Upon receipt of one recvmsg call, the caller must |
| 15 | * provide a buffer which is tracked with the RX SGL. |
| 16 | * |
| 17 | * During the processing of the recvmsg operation, the cipher request is |
| 18 | * allocated and prepared. As part of the recvmsg operation, the processed |
| 19 | * TX buffers are extracted from the TX SGL into a separate SGL. |
| 20 | * |
| 21 | * After the completion of the crypto operation, the RX SGL and the cipher |
| 22 | * request is released. The extracted TX SGL parts are released together with |
| 23 | * the RX SGL release. |
| 24 | */ |
| 25 | |
| 26 | #include <crypto/scatterwalk.h> |
| 27 | #include <crypto/skcipher.h> |
| 28 | #include <crypto/if_alg.h> |
| 29 | #include <linux/init.h> |
| 30 | #include <linux/list.h> |
| 31 | #include <linux/kernel.h> |
| 32 | #include <linux/mm.h> |
| 33 | #include <linux/module.h> |
| 34 | #include <linux/net.h> |
| 35 | #include <net/sock.h> |
| 36 | |
| 37 | static int skcipher_sendmsg(struct socket *sock, struct msghdr *msg, |
| 38 | size_t size) |
| 39 | { |
| 40 | struct sock *sk = sock->sk; |
| 41 | struct alg_sock *ask = alg_sk(sk); |
| 42 | struct sock *psk = ask->parent; |
| 43 | struct alg_sock *pask = alg_sk(psk); |
| 44 | struct crypto_skcipher *tfm = pask->private; |
| 45 | unsigned ivsize = crypto_skcipher_ivsize(tfm); |
| 46 | |
| 47 | return af_alg_sendmsg(sock, msg, size, ivsize); |
| 48 | } |
| 49 | |
| 50 | static int _skcipher_recvmsg(struct socket *sock, struct msghdr *msg, |
| 51 | size_t ignored, int flags) |
| 52 | { |
| 53 | struct sock *sk = sock->sk; |
| 54 | struct alg_sock *ask = alg_sk(sk); |
| 55 | struct sock *psk = ask->parent; |
| 56 | struct alg_sock *pask = alg_sk(psk); |
| 57 | struct af_alg_ctx *ctx = ask->private; |
| 58 | struct crypto_skcipher *tfm = pask->private; |
| 59 | unsigned int bs = crypto_skcipher_chunksize(tfm); |
| 60 | struct af_alg_async_req *areq; |
| 61 | int err = 0; |
| 62 | size_t len = 0; |
| 63 | |
| 64 | if (!ctx->init || (ctx->more && ctx->used < bs)) { |
| 65 | err = af_alg_wait_for_data(sk, flags, bs); |
| 66 | if (err) |
| 67 | return err; |
| 68 | } |
| 69 | |
| 70 | /* Allocate cipher request for current operation. */ |
| 71 | areq = af_alg_alloc_areq(sk, sizeof(struct af_alg_async_req) + |
| 72 | crypto_skcipher_reqsize(tfm)); |
| 73 | if (IS_ERR(areq)) |
| 74 | return PTR_ERR(areq); |
| 75 | |
| 76 | /* convert iovecs of output buffers into RX SGL */ |
| 77 | err = af_alg_get_rsgl(sk, msg, flags, areq, ctx->used, &len); |
| 78 | if (err) |
| 79 | goto free; |
| 80 | |
| 81 | /* |
| 82 | * If more buffers are to be expected to be processed, process only |
| 83 | * full block size buffers. |
| 84 | */ |
| 85 | if (ctx->more || len < ctx->used) |
| 86 | len -= len % bs; |
| 87 | |
| 88 | /* |
| 89 | * Create a per request TX SGL for this request which tracks the |
| 90 | * SG entries from the global TX SGL. |
| 91 | */ |
| 92 | areq->tsgl_entries = af_alg_count_tsgl(sk, len, 0); |
| 93 | if (!areq->tsgl_entries) |
| 94 | areq->tsgl_entries = 1; |
| 95 | areq->tsgl = sock_kmalloc(sk, array_size(sizeof(*areq->tsgl), |
| 96 | areq->tsgl_entries), |
| 97 | GFP_KERNEL); |
| 98 | if (!areq->tsgl) { |
| 99 | err = -ENOMEM; |
| 100 | goto free; |
| 101 | } |
| 102 | sg_init_table(areq->tsgl, areq->tsgl_entries); |
| 103 | af_alg_pull_tsgl(sk, len, areq->tsgl, 0); |
| 104 | |
| 105 | /* Initialize the crypto operation */ |
| 106 | skcipher_request_set_tfm(&areq->cra_u.skcipher_req, tfm); |
| 107 | skcipher_request_set_crypt(&areq->cra_u.skcipher_req, areq->tsgl, |
| 108 | areq->first_rsgl.sgl.sg, len, ctx->iv); |
| 109 | |
| 110 | if (msg->msg_iocb && !is_sync_kiocb(msg->msg_iocb)) { |
| 111 | /* AIO operation */ |
| 112 | sock_hold(sk); |
| 113 | areq->iocb = msg->msg_iocb; |
| 114 | |
| 115 | /* Remember output size that will be generated. */ |
| 116 | areq->outlen = len; |
| 117 | |
| 118 | skcipher_request_set_callback(&areq->cra_u.skcipher_req, |
| 119 | CRYPTO_TFM_REQ_MAY_SLEEP, |
| 120 | af_alg_async_cb, areq); |
| 121 | err = ctx->enc ? |
| 122 | crypto_skcipher_encrypt(&areq->cra_u.skcipher_req) : |
| 123 | crypto_skcipher_decrypt(&areq->cra_u.skcipher_req); |
| 124 | |
| 125 | /* AIO operation in progress */ |
| 126 | if (err == -EINPROGRESS) |
| 127 | return -EIOCBQUEUED; |
| 128 | |
| 129 | sock_put(sk); |
| 130 | } else { |
| 131 | /* Synchronous operation */ |
| 132 | skcipher_request_set_callback(&areq->cra_u.skcipher_req, |
| 133 | CRYPTO_TFM_REQ_MAY_SLEEP | |
| 134 | CRYPTO_TFM_REQ_MAY_BACKLOG, |
| 135 | crypto_req_done, &ctx->wait); |
| 136 | err = crypto_wait_req(ctx->enc ? |
| 137 | crypto_skcipher_encrypt(&areq->cra_u.skcipher_req) : |
| 138 | crypto_skcipher_decrypt(&areq->cra_u.skcipher_req), |
| 139 | &ctx->wait); |
| 140 | } |
| 141 | |
| 142 | |
| 143 | free: |
| 144 | af_alg_free_resources(areq); |
| 145 | |
| 146 | return err ? err : len; |
| 147 | } |
| 148 | |
| 149 | static int skcipher_recvmsg(struct socket *sock, struct msghdr *msg, |
| 150 | size_t ignored, int flags) |
| 151 | { |
| 152 | struct sock *sk = sock->sk; |
| 153 | int ret = 0; |
| 154 | |
| 155 | lock_sock(sk); |
| 156 | while (msg_data_left(msg)) { |
| 157 | int err = _skcipher_recvmsg(sock, msg, ignored, flags); |
| 158 | |
| 159 | /* |
| 160 | * This error covers -EIOCBQUEUED which implies that we can |
| 161 | * only handle one AIO request. If the caller wants to have |
| 162 | * multiple AIO requests in parallel, he must make multiple |
| 163 | * separate AIO calls. |
| 164 | * |
| 165 | * Also return the error if no data has been processed so far. |
| 166 | */ |
| 167 | if (err <= 0) { |
| 168 | if (err == -EIOCBQUEUED || !ret) |
| 169 | ret = err; |
| 170 | goto out; |
| 171 | } |
| 172 | |
| 173 | ret += err; |
| 174 | } |
| 175 | |
| 176 | out: |
| 177 | af_alg_wmem_wakeup(sk); |
| 178 | release_sock(sk); |
| 179 | return ret; |
| 180 | } |
| 181 | |
| 182 | static struct proto_ops algif_skcipher_ops = { |
| 183 | .family = PF_ALG, |
| 184 | |
| 185 | .connect = sock_no_connect, |
| 186 | .socketpair = sock_no_socketpair, |
| 187 | .getname = sock_no_getname, |
| 188 | .ioctl = sock_no_ioctl, |
| 189 | .listen = sock_no_listen, |
| 190 | .shutdown = sock_no_shutdown, |
| 191 | .mmap = sock_no_mmap, |
| 192 | .bind = sock_no_bind, |
| 193 | .accept = sock_no_accept, |
| 194 | |
| 195 | .release = af_alg_release, |
| 196 | .sendmsg = skcipher_sendmsg, |
| 197 | .sendpage = af_alg_sendpage, |
| 198 | .recvmsg = skcipher_recvmsg, |
| 199 | .poll = af_alg_poll, |
| 200 | }; |
| 201 | |
| 202 | static int skcipher_check_key(struct socket *sock) |
| 203 | { |
| 204 | int err = 0; |
| 205 | struct sock *psk; |
| 206 | struct alg_sock *pask; |
| 207 | struct crypto_skcipher *tfm; |
| 208 | struct sock *sk = sock->sk; |
| 209 | struct alg_sock *ask = alg_sk(sk); |
| 210 | |
| 211 | lock_sock(sk); |
| 212 | if (!atomic_read(&ask->nokey_refcnt)) |
| 213 | goto unlock_child; |
| 214 | |
| 215 | psk = ask->parent; |
| 216 | pask = alg_sk(ask->parent); |
| 217 | tfm = pask->private; |
| 218 | |
| 219 | err = -ENOKEY; |
| 220 | lock_sock_nested(psk, SINGLE_DEPTH_NESTING); |
| 221 | if (crypto_skcipher_get_flags(tfm) & CRYPTO_TFM_NEED_KEY) |
| 222 | goto unlock; |
| 223 | |
| 224 | atomic_dec(&pask->nokey_refcnt); |
| 225 | atomic_set(&ask->nokey_refcnt, 0); |
| 226 | |
| 227 | err = 0; |
| 228 | |
| 229 | unlock: |
| 230 | release_sock(psk); |
| 231 | unlock_child: |
| 232 | release_sock(sk); |
| 233 | |
| 234 | return err; |
| 235 | } |
| 236 | |
| 237 | static int skcipher_sendmsg_nokey(struct socket *sock, struct msghdr *msg, |
| 238 | size_t size) |
| 239 | { |
| 240 | int err; |
| 241 | |
| 242 | err = skcipher_check_key(sock); |
| 243 | if (err) |
| 244 | return err; |
| 245 | |
| 246 | return skcipher_sendmsg(sock, msg, size); |
| 247 | } |
| 248 | |
| 249 | static ssize_t skcipher_sendpage_nokey(struct socket *sock, struct page *page, |
| 250 | int offset, size_t size, int flags) |
| 251 | { |
| 252 | int err; |
| 253 | |
| 254 | err = skcipher_check_key(sock); |
| 255 | if (err) |
| 256 | return err; |
| 257 | |
| 258 | return af_alg_sendpage(sock, page, offset, size, flags); |
| 259 | } |
| 260 | |
| 261 | static int skcipher_recvmsg_nokey(struct socket *sock, struct msghdr *msg, |
| 262 | size_t ignored, int flags) |
| 263 | { |
| 264 | int err; |
| 265 | |
| 266 | err = skcipher_check_key(sock); |
| 267 | if (err) |
| 268 | return err; |
| 269 | |
| 270 | return skcipher_recvmsg(sock, msg, ignored, flags); |
| 271 | } |
| 272 | |
| 273 | static struct proto_ops algif_skcipher_ops_nokey = { |
| 274 | .family = PF_ALG, |
| 275 | |
| 276 | .connect = sock_no_connect, |
| 277 | .socketpair = sock_no_socketpair, |
| 278 | .getname = sock_no_getname, |
| 279 | .ioctl = sock_no_ioctl, |
| 280 | .listen = sock_no_listen, |
| 281 | .shutdown = sock_no_shutdown, |
| 282 | .mmap = sock_no_mmap, |
| 283 | .bind = sock_no_bind, |
| 284 | .accept = sock_no_accept, |
| 285 | |
| 286 | .release = af_alg_release, |
| 287 | .sendmsg = skcipher_sendmsg_nokey, |
| 288 | .sendpage = skcipher_sendpage_nokey, |
| 289 | .recvmsg = skcipher_recvmsg_nokey, |
| 290 | .poll = af_alg_poll, |
| 291 | }; |
| 292 | |
| 293 | static void *skcipher_bind(const char *name, u32 type, u32 mask) |
| 294 | { |
| 295 | return crypto_alloc_skcipher(name, type, mask); |
| 296 | } |
| 297 | |
| 298 | static void skcipher_release(void *private) |
| 299 | { |
| 300 | crypto_free_skcipher(private); |
| 301 | } |
| 302 | |
| 303 | static int skcipher_setkey(void *private, const u8 *key, unsigned int keylen) |
| 304 | { |
| 305 | return crypto_skcipher_setkey(private, key, keylen); |
| 306 | } |
| 307 | |
| 308 | static void skcipher_sock_destruct(struct sock *sk) |
| 309 | { |
| 310 | struct alg_sock *ask = alg_sk(sk); |
| 311 | struct af_alg_ctx *ctx = ask->private; |
| 312 | struct sock *psk = ask->parent; |
| 313 | struct alg_sock *pask = alg_sk(psk); |
| 314 | struct crypto_skcipher *tfm = pask->private; |
| 315 | |
| 316 | af_alg_pull_tsgl(sk, ctx->used, NULL, 0); |
| 317 | sock_kzfree_s(sk, ctx->iv, crypto_skcipher_ivsize(tfm)); |
| 318 | sock_kfree_s(sk, ctx, ctx->len); |
| 319 | af_alg_release_parent(sk); |
| 320 | } |
| 321 | |
| 322 | static int skcipher_accept_parent_nokey(void *private, struct sock *sk) |
| 323 | { |
| 324 | struct af_alg_ctx *ctx; |
| 325 | struct alg_sock *ask = alg_sk(sk); |
| 326 | struct crypto_skcipher *tfm = private; |
| 327 | unsigned int len = sizeof(*ctx); |
| 328 | |
| 329 | ctx = sock_kmalloc(sk, len, GFP_KERNEL); |
| 330 | if (!ctx) |
| 331 | return -ENOMEM; |
| 332 | memset(ctx, 0, len); |
| 333 | |
| 334 | ctx->iv = sock_kmalloc(sk, crypto_skcipher_ivsize(tfm), |
| 335 | GFP_KERNEL); |
| 336 | if (!ctx->iv) { |
| 337 | sock_kfree_s(sk, ctx, len); |
| 338 | return -ENOMEM; |
| 339 | } |
| 340 | memset(ctx->iv, 0, crypto_skcipher_ivsize(tfm)); |
| 341 | |
| 342 | INIT_LIST_HEAD(&ctx->tsgl_list); |
| 343 | ctx->len = len; |
| 344 | crypto_init_wait(&ctx->wait); |
| 345 | |
| 346 | ask->private = ctx; |
| 347 | |
| 348 | sk->sk_destruct = skcipher_sock_destruct; |
| 349 | |
| 350 | return 0; |
| 351 | } |
| 352 | |
| 353 | static int skcipher_accept_parent(void *private, struct sock *sk) |
| 354 | { |
| 355 | struct crypto_skcipher *tfm = private; |
| 356 | |
| 357 | if (crypto_skcipher_get_flags(tfm) & CRYPTO_TFM_NEED_KEY) |
| 358 | return -ENOKEY; |
| 359 | |
| 360 | return skcipher_accept_parent_nokey(private, sk); |
| 361 | } |
| 362 | |
| 363 | static const struct af_alg_type algif_type_skcipher = { |
| 364 | .bind = skcipher_bind, |
| 365 | .release = skcipher_release, |
| 366 | .setkey = skcipher_setkey, |
| 367 | .accept = skcipher_accept_parent, |
| 368 | .accept_nokey = skcipher_accept_parent_nokey, |
| 369 | .ops = &algif_skcipher_ops, |
| 370 | .ops_nokey = &algif_skcipher_ops_nokey, |
| 371 | .name = "skcipher", |
| 372 | .owner = THIS_MODULE |
| 373 | }; |
| 374 | |
| 375 | static int __init algif_skcipher_init(void) |
| 376 | { |
| 377 | return af_alg_register_type(&algif_type_skcipher); |
| 378 | } |
| 379 | |
| 380 | static void __exit algif_skcipher_exit(void) |
| 381 | { |
| 382 | int err = af_alg_unregister_type(&algif_type_skcipher); |
| 383 | BUG_ON(err); |
| 384 | } |
| 385 | |
| 386 | module_init(algif_skcipher_init); |
| 387 | module_exit(algif_skcipher_exit); |
| 388 | MODULE_LICENSE("GPL"); |