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1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * algif_skcipher: User-space interface for skcipher algorithms4 *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 is12 * filled by user space with the data submitted via sendmsg. Filling up the TX13 * SGL does not cause a crypto operation -- the data will only be tracked by14 * the kernel. Upon receipt of one recvmsg call, the caller must provide a15 * buffer which is tracked with the RX SGL.16 *17 * During the processing of the recvmsg operation, the cipher request is18 * allocated and prepared. As part of the recvmsg operation, the processed19 * 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 cipher22 * request is released. The extracted TX SGL parts are released together with23 * 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 37static 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 50static int algif_skcipher_export(struct sock *sk, struct skcipher_request *req)51{52 struct alg_sock *ask = alg_sk(sk);53 struct crypto_skcipher *tfm;54 struct af_alg_ctx *ctx;55 struct alg_sock *pask;56 unsigned statesize;57 struct sock *psk;58 int err;59 60 if (!(req->base.flags & CRYPTO_SKCIPHER_REQ_NOTFINAL))61 return 0;62 63 ctx = ask->private;64 psk = ask->parent;65 pask = alg_sk(psk);66 tfm = pask->private;67 68 statesize = crypto_skcipher_statesize(tfm);69 ctx->state = sock_kmalloc(sk, statesize, GFP_ATOMIC);70 if (!ctx->state)71 return -ENOMEM;72 73 err = crypto_skcipher_export(req, ctx->state);74 if (err) {75 sock_kzfree_s(sk, ctx->state, statesize);76 ctx->state = NULL;77 }78 79 return err;80}81 82static void algif_skcipher_done(void *data, int err)83{84 struct af_alg_async_req *areq = data;85 struct sock *sk = areq->sk;86 87 if (err)88 goto out;89 90 err = algif_skcipher_export(sk, &areq->cra_u.skcipher_req);91 92out:93 af_alg_async_cb(data, err);94}95 96static int _skcipher_recvmsg(struct socket *sock, struct msghdr *msg,97 size_t ignored, int flags)98{99 struct sock *sk = sock->sk;100 struct alg_sock *ask = alg_sk(sk);101 struct sock *psk = ask->parent;102 struct alg_sock *pask = alg_sk(psk);103 struct af_alg_ctx *ctx = ask->private;104 struct crypto_skcipher *tfm = pask->private;105 unsigned int bs = crypto_skcipher_chunksize(tfm);106 struct af_alg_async_req *areq;107 unsigned cflags = 0;108 int err = 0;109 size_t len = 0;110 111 if (!ctx->init || (ctx->more && ctx->used < bs)) {112 err = af_alg_wait_for_data(sk, flags, bs);113 if (err)114 return err;115 }116 117 /* Allocate cipher request for current operation. */118 areq = af_alg_alloc_areq(sk, sizeof(struct af_alg_async_req) +119 crypto_skcipher_reqsize(tfm));120 if (IS_ERR(areq))121 return PTR_ERR(areq);122 123 /* convert iovecs of output buffers into RX SGL */124 err = af_alg_get_rsgl(sk, msg, flags, areq, ctx->used, &len);125 if (err)126 goto free;127 128 /*129 * If more buffers are to be expected to be processed, process only130 * full block size buffers.131 */132 if (ctx->more || len < ctx->used) {133 len -= len % bs;134 cflags |= CRYPTO_SKCIPHER_REQ_NOTFINAL;135 }136 137 /*138 * Create a per request TX SGL for this request which tracks the139 * SG entries from the global TX SGL.140 */141 areq->tsgl_entries = af_alg_count_tsgl(sk, len, 0);142 if (!areq->tsgl_entries)143 areq->tsgl_entries = 1;144 areq->tsgl = sock_kmalloc(sk, array_size(sizeof(*areq->tsgl),145 areq->tsgl_entries),146 GFP_KERNEL);147 if (!areq->tsgl) {148 err = -ENOMEM;149 goto free;150 }151 sg_init_table(areq->tsgl, areq->tsgl_entries);152 af_alg_pull_tsgl(sk, len, areq->tsgl, 0);153 154 /* Initialize the crypto operation */155 skcipher_request_set_tfm(&areq->cra_u.skcipher_req, tfm);156 skcipher_request_set_crypt(&areq->cra_u.skcipher_req, areq->tsgl,157 areq->first_rsgl.sgl.sgt.sgl, len, ctx->iv);158 159 if (ctx->state) {160 err = crypto_skcipher_import(&areq->cra_u.skcipher_req,161 ctx->state);162 sock_kzfree_s(sk, ctx->state, crypto_skcipher_statesize(tfm));163 ctx->state = NULL;164 if (err)165 goto free;166 cflags |= CRYPTO_SKCIPHER_REQ_CONT;167 }168 169 if (msg->msg_iocb && !is_sync_kiocb(msg->msg_iocb)) {170 /* AIO operation */171 sock_hold(sk);172 areq->iocb = msg->msg_iocb;173 174 /* Remember output size that will be generated. */175 areq->outlen = len;176 177 skcipher_request_set_callback(&areq->cra_u.skcipher_req,178 cflags |179 CRYPTO_TFM_REQ_MAY_SLEEP,180 algif_skcipher_done, areq);181 err = ctx->enc ?182 crypto_skcipher_encrypt(&areq->cra_u.skcipher_req) :183 crypto_skcipher_decrypt(&areq->cra_u.skcipher_req);184 185 /* AIO operation in progress */186 if (err == -EINPROGRESS)187 return -EIOCBQUEUED;188 189 sock_put(sk);190 } else {191 /* Synchronous operation */192 skcipher_request_set_callback(&areq->cra_u.skcipher_req,193 cflags |194 CRYPTO_TFM_REQ_MAY_SLEEP |195 CRYPTO_TFM_REQ_MAY_BACKLOG,196 crypto_req_done, &ctx->wait);197 err = crypto_wait_req(ctx->enc ?198 crypto_skcipher_encrypt(&areq->cra_u.skcipher_req) :199 crypto_skcipher_decrypt(&areq->cra_u.skcipher_req),200 &ctx->wait);201 202 if (!err)203 err = algif_skcipher_export(204 sk, &areq->cra_u.skcipher_req);205 }206 207free:208 af_alg_free_resources(areq);209 210 return err ? err : len;211}212 213static int skcipher_recvmsg(struct socket *sock, struct msghdr *msg,214 size_t ignored, int flags)215{216 struct sock *sk = sock->sk;217 int ret = 0;218 219 lock_sock(sk);220 while (msg_data_left(msg)) {221 int err = _skcipher_recvmsg(sock, msg, ignored, flags);222 223 /*224 * This error covers -EIOCBQUEUED which implies that we can225 * only handle one AIO request. If the caller wants to have226 * multiple AIO requests in parallel, he must make multiple227 * separate AIO calls.228 *229 * Also return the error if no data has been processed so far.230 */231 if (err <= 0) {232 if (err == -EIOCBQUEUED || !ret)233 ret = err;234 goto out;235 }236 237 ret += err;238 }239 240out:241 af_alg_wmem_wakeup(sk);242 release_sock(sk);243 return ret;244}245 246static struct proto_ops algif_skcipher_ops = {247 .family = PF_ALG,248 249 .connect = sock_no_connect,250 .socketpair = sock_no_socketpair,251 .getname = sock_no_getname,252 .ioctl = sock_no_ioctl,253 .listen = sock_no_listen,254 .shutdown = sock_no_shutdown,255 .mmap = sock_no_mmap,256 .bind = sock_no_bind,257 .accept = sock_no_accept,258 259 .release = af_alg_release,260 .sendmsg = skcipher_sendmsg,261 .recvmsg = skcipher_recvmsg,262 .poll = af_alg_poll,263};264 265static int skcipher_check_key(struct socket *sock)266{267 int err = 0;268 struct sock *psk;269 struct alg_sock *pask;270 struct crypto_skcipher *tfm;271 struct sock *sk = sock->sk;272 struct alg_sock *ask = alg_sk(sk);273 274 lock_sock(sk);275 if (!atomic_read(&ask->nokey_refcnt))276 goto unlock_child;277 278 psk = ask->parent;279 pask = alg_sk(ask->parent);280 tfm = pask->private;281 282 err = -ENOKEY;283 lock_sock_nested(psk, SINGLE_DEPTH_NESTING);284 if (crypto_skcipher_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)285 goto unlock;286 287 atomic_dec(&pask->nokey_refcnt);288 atomic_set(&ask->nokey_refcnt, 0);289 290 err = 0;291 292unlock:293 release_sock(psk);294unlock_child:295 release_sock(sk);296 297 return err;298}299 300static int skcipher_sendmsg_nokey(struct socket *sock, struct msghdr *msg,301 size_t size)302{303 int err;304 305 err = skcipher_check_key(sock);306 if (err)307 return err;308 309 return skcipher_sendmsg(sock, msg, size);310}311 312static int skcipher_recvmsg_nokey(struct socket *sock, struct msghdr *msg,313 size_t ignored, int flags)314{315 int err;316 317 err = skcipher_check_key(sock);318 if (err)319 return err;320 321 return skcipher_recvmsg(sock, msg, ignored, flags);322}323 324static struct proto_ops algif_skcipher_ops_nokey = {325 .family = PF_ALG,326 327 .connect = sock_no_connect,328 .socketpair = sock_no_socketpair,329 .getname = sock_no_getname,330 .ioctl = sock_no_ioctl,331 .listen = sock_no_listen,332 .shutdown = sock_no_shutdown,333 .mmap = sock_no_mmap,334 .bind = sock_no_bind,335 .accept = sock_no_accept,336 337 .release = af_alg_release,338 .sendmsg = skcipher_sendmsg_nokey,339 .recvmsg = skcipher_recvmsg_nokey,340 .poll = af_alg_poll,341};342 343static void *skcipher_bind(const char *name, u32 type, u32 mask)344{345 return crypto_alloc_skcipher(name, type, mask);346}347 348static void skcipher_release(void *private)349{350 crypto_free_skcipher(private);351}352 353static int skcipher_setkey(void *private, const u8 *key, unsigned int keylen)354{355 return crypto_skcipher_setkey(private, key, keylen);356}357 358static void skcipher_sock_destruct(struct sock *sk)359{360 struct alg_sock *ask = alg_sk(sk);361 struct af_alg_ctx *ctx = ask->private;362 struct sock *psk = ask->parent;363 struct alg_sock *pask = alg_sk(psk);364 struct crypto_skcipher *tfm = pask->private;365 366 af_alg_pull_tsgl(sk, ctx->used, NULL, 0);367 sock_kzfree_s(sk, ctx->iv, crypto_skcipher_ivsize(tfm));368 if (ctx->state)369 sock_kzfree_s(sk, ctx->state, crypto_skcipher_statesize(tfm));370 sock_kfree_s(sk, ctx, ctx->len);371 af_alg_release_parent(sk);372}373 374static int skcipher_accept_parent_nokey(void *private, struct sock *sk)375{376 struct af_alg_ctx *ctx;377 struct alg_sock *ask = alg_sk(sk);378 struct crypto_skcipher *tfm = private;379 unsigned int len = sizeof(*ctx);380 381 ctx = sock_kmalloc(sk, len, GFP_KERNEL);382 if (!ctx)383 return -ENOMEM;384 memset(ctx, 0, len);385 386 ctx->iv = sock_kmalloc(sk, crypto_skcipher_ivsize(tfm),387 GFP_KERNEL);388 if (!ctx->iv) {389 sock_kfree_s(sk, ctx, len);390 return -ENOMEM;391 }392 memset(ctx->iv, 0, crypto_skcipher_ivsize(tfm));393 394 INIT_LIST_HEAD(&ctx->tsgl_list);395 ctx->len = len;396 crypto_init_wait(&ctx->wait);397 398 ask->private = ctx;399 400 sk->sk_destruct = skcipher_sock_destruct;401 402 return 0;403}404 405static int skcipher_accept_parent(void *private, struct sock *sk)406{407 struct crypto_skcipher *tfm = private;408 409 if (crypto_skcipher_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)410 return -ENOKEY;411 412 return skcipher_accept_parent_nokey(private, sk);413}414 415static const struct af_alg_type algif_type_skcipher = {416 .bind = skcipher_bind,417 .release = skcipher_release,418 .setkey = skcipher_setkey,419 .accept = skcipher_accept_parent,420 .accept_nokey = skcipher_accept_parent_nokey,421 .ops = &algif_skcipher_ops,422 .ops_nokey = &algif_skcipher_ops_nokey,423 .name = "skcipher",424 .owner = THIS_MODULE425};426 427static int __init algif_skcipher_init(void)428{429 return af_alg_register_type(&algif_type_skcipher);430}431 432static void __exit algif_skcipher_exit(void)433{434 int err = af_alg_unregister_type(&algif_type_skcipher);435 BUG_ON(err);436}437 438module_init(algif_skcipher_init);439module_exit(algif_skcipher_exit);440MODULE_DESCRIPTION("Userspace interface for skcipher algorithms");441MODULE_LICENSE("GPL");442