algif_skcipher.c

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    1 /*
    2  * algif_skcipher: User-space interface for skcipher algorithms
    3  *
    4  * This file provides the user-space API for symmetric key ciphers.
    5  *
    6  * Copyright (c) 2010 Herbert Xu <herbert@gondor.apana.org.au>
    7  *
    8  * This program is free software; you can redistribute it and/or modify it
    9  * under the terms of the GNU General Public License as published by the Free
   10  * Software Foundation; either version 2 of the License, or (at your option)
   11  * any later version.
   12  *
   13  */
   14 
   15 #include <crypto/scatterwalk.h>
   16 #include <crypto/skcipher.h>
   17 #include <crypto/if_alg.h>
   18 #include <linux/init.h>
   19 #include <linux/list.h>
   20 #include <linux/kernel.h>
   21 #include <linux/mm.h>
   22 #include <linux/module.h>
   23 #include <linux/net.h>
   24 #include <net/sock.h>
   25 
   26 struct skcipher_sg_list {
   27         struct list_head list;
   28 
   29         int cur;
   30 
   31         struct scatterlist sg[0];
   32 };
   33 
   34 struct skcipher_ctx {
   35         struct list_head tsgl;
   36         struct af_alg_sgl rsgl;
   37 
   38         void *iv;
   39 
   40         struct af_alg_completion completion;
   41 
   42         unsigned used;
   43 
   44         unsigned int len;
   45         bool more;
   46         bool merge;
   47         bool enc;
   48 
   49         struct ablkcipher_request req;
   50 };
   51 
   52 #define MAX_SGL_ENTS ((PAGE_SIZE - sizeof(struct skcipher_sg_list)) / \
   53                       sizeof(struct scatterlist) - 1)
   54 
   55 static inline int skcipher_sndbuf(struct sock *sk)
   56 {
   57         struct alg_sock *ask = alg_sk(sk);
   58         struct skcipher_ctx *ctx = ask->private;
   59 
   60         return max_t(int, max_t(int, sk->sk_sndbuf & PAGE_MASK, PAGE_SIZE) -
   61                           ctx->used, 0);
   62 }
   63 
   64 static inline bool skcipher_writable(struct sock *sk)
   65 {
   66         return PAGE_SIZE <= skcipher_sndbuf(sk);
   67 }
   68 
   69 static int skcipher_alloc_sgl(struct sock *sk)
   70 {
   71         struct alg_sock *ask = alg_sk(sk);
   72         struct skcipher_ctx *ctx = ask->private;
   73         struct skcipher_sg_list *sgl;
   74         struct scatterlist *sg = NULL;
   75 
   76         sgl = list_entry(ctx->tsgl.prev, struct skcipher_sg_list, list);
   77         if (!list_empty(&ctx->tsgl))
   78                 sg = sgl->sg;
   79 
   80         if (!sg || sgl->cur >= MAX_SGL_ENTS) {
   81                 sgl = sock_kmalloc(sk, sizeof(*sgl) +
   82                                        sizeof(sgl->sg[0]) * (MAX_SGL_ENTS + 1),
   83                                    GFP_KERNEL);
   84                 if (!sgl)
   85                         return -ENOMEM;
   86 
   87                 sg_init_table(sgl->sg, MAX_SGL_ENTS + 1);
   88                 sgl->cur = 0;
   89 
   90                 if (sg)
   91                         scatterwalk_sg_chain(sg, MAX_SGL_ENTS + 1, sgl->sg);
   92 
   93                 list_add_tail(&sgl->list, &ctx->tsgl);
   94         }
   95 
   96         return 0;
   97 }
   98 
   99 static void skcipher_pull_sgl(struct sock *sk, int used)
  100 {
  101         struct alg_sock *ask = alg_sk(sk);
  102         struct skcipher_ctx *ctx = ask->private;
  103         struct skcipher_sg_list *sgl;
  104         struct scatterlist *sg;
  105         int i;
  106 
  107         while (!list_empty(&ctx->tsgl)) {
  108                 sgl = list_first_entry(&ctx->tsgl, struct skcipher_sg_list,
  109                                        list);
  110                 sg = sgl->sg;
  111 
  112                 for (i = 0; i < sgl->cur; i++) {
  113                         int plen = min_t(int, used, sg[i].length);
  114 
  115                         if (!sg_page(sg + i))
  116                                 continue;
  117 
  118                         sg[i].length -= plen;
  119                         sg[i].offset += plen;
  120 
  121                         used -= plen;
  122                         ctx->used -= plen;
  123 
  124                         if (sg[i].length)
  125                                 return;
  126 
  127                         put_page(sg_page(sg + i));
  128                         sg_assign_page(sg + i, NULL);
  129                 }
  130 
  131                 list_del(&sgl->list);
  132                 sock_kfree_s(sk, sgl,
  133                              sizeof(*sgl) + sizeof(sgl->sg[0]) *
  134                                             (MAX_SGL_ENTS + 1));
  135         }
  136 
  137         if (!ctx->used)
  138                 ctx->merge = 0;
  139 }
  140 
  141 static void skcipher_free_sgl(struct sock *sk)
  142 {
  143         struct alg_sock *ask = alg_sk(sk);
  144         struct skcipher_ctx *ctx = ask->private;
  145 
  146         skcipher_pull_sgl(sk, ctx->used);
  147 }
  148 
  149 static int skcipher_wait_for_wmem(struct sock *sk, unsigned flags)
  150 {
  151         long timeout;
  152         DEFINE_WAIT(wait);
  153         int err = -ERESTARTSYS;
  154 
  155         if (flags & MSG_DONTWAIT)
  156                 return -EAGAIN;
  157 
  158         set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
  159 
  160         for (;;) {
  161                 if (signal_pending(current))
  162                         break;
  163                 prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
  164                 timeout = MAX_SCHEDULE_TIMEOUT;
  165                 if (sk_wait_event(sk, &timeout, skcipher_writable(sk))) {
  166                         err = 0;
  167                         break;
  168                 }
  169         }
  170         finish_wait(sk_sleep(sk), &wait);
  171 
  172         return err;
  173 }
  174 
  175 static void skcipher_wmem_wakeup(struct sock *sk)
  176 {
  177         struct socket_wq *wq;
  178 
  179         if (!skcipher_writable(sk))
  180                 return;
  181 
  182         rcu_read_lock();
  183         wq = rcu_dereference(sk->sk_wq);
  184         if (wq_has_sleeper(wq))
  185                 wake_up_interruptible_sync_poll(&wq->wait, POLLIN |
  186                                                            POLLRDNORM |
  187                                                            POLLRDBAND);
  188         sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_IN);
  189         rcu_read_unlock();
  190 }
  191 
  192 static int skcipher_wait_for_data(struct sock *sk, unsigned flags)
  193 {
  194         struct alg_sock *ask = alg_sk(sk);
  195         struct skcipher_ctx *ctx = ask->private;
  196         long timeout;
  197         DEFINE_WAIT(wait);
  198         int err = -ERESTARTSYS;
  199 
  200         if (flags & MSG_DONTWAIT) {
  201                 return -EAGAIN;
  202         }
  203 
  204         set_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
  205 
  206         for (;;) {
  207                 if (signal_pending(current))
  208                         break;
  209                 prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
  210                 timeout = MAX_SCHEDULE_TIMEOUT;
  211                 if (sk_wait_event(sk, &timeout, ctx->used)) {
  212                         err = 0;
  213                         break;
  214                 }
  215         }
  216         finish_wait(sk_sleep(sk), &wait);
  217 
  218         clear_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
  219 
  220         return err;
  221 }
  222 
  223 static void skcipher_data_wakeup(struct sock *sk)
  224 {
  225         struct alg_sock *ask = alg_sk(sk);
  226         struct skcipher_ctx *ctx = ask->private;
  227         struct socket_wq *wq;
  228 
  229         if (!ctx->used)
  230                 return;
  231 
  232         rcu_read_lock();
  233         wq = rcu_dereference(sk->sk_wq);
  234         if (wq_has_sleeper(wq))
  235                 wake_up_interruptible_sync_poll(&wq->wait, POLLOUT |
  236                                                            POLLRDNORM |
  237                                                            POLLRDBAND);
  238         sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT);
  239         rcu_read_unlock();
  240 }
  241 
  242 static int skcipher_sendmsg(struct kiocb *unused, struct socket *sock,
  243                             struct msghdr *msg, size_t size)
  244 {
  245         struct sock *sk = sock->sk;
  246         struct alg_sock *ask = alg_sk(sk);
  247         struct skcipher_ctx *ctx = ask->private;
  248         struct crypto_ablkcipher *tfm = crypto_ablkcipher_reqtfm(&ctx->req);
  249         unsigned ivsize = crypto_ablkcipher_ivsize(tfm);
  250         struct skcipher_sg_list *sgl;
  251         struct af_alg_control con = {};
  252         long copied = 0;
  253         bool enc = 0;
  254         int err;
  255         int i;
  256 
  257         if (msg->msg_controllen) {
  258                 err = af_alg_cmsg_send(msg, &con);
  259                 if (err)
  260                         return err;
  261 
  262                 switch (con.op) {
  263                 case ALG_OP_ENCRYPT:
  264                         enc = 1;
  265                         break;
  266                 case ALG_OP_DECRYPT:
  267                         enc = 0;
  268                         break;
  269                 default:
  270                         return -EINVAL;
  271                 }
  272 
  273                 if (con.iv && con.iv->ivlen != ivsize)
  274                         return -EINVAL;
  275         }
  276 
  277         err = -EINVAL;
  278 
  279         lock_sock(sk);
  280         if (!ctx->more && ctx->used)
  281                 goto unlock;
  282 
  283         if (!ctx->used) {
  284                 ctx->enc = enc;
  285                 if (con.iv)
  286                         memcpy(ctx->iv, con.iv->iv, ivsize);
  287         }
  288 
  289         while (size) {
  290                 struct scatterlist *sg;
  291                 unsigned long len = size;
  292                 int plen;
  293 
  294                 if (ctx->merge) {
  295                         sgl = list_entry(ctx->tsgl.prev,
  296                                          struct skcipher_sg_list, list);
  297                         sg = sgl->sg + sgl->cur - 1;
  298                         len = min_t(unsigned long, len,
  299                                     PAGE_SIZE - sg->offset - sg->length);
  300 
  301                         err = memcpy_fromiovec(page_address(sg_page(sg)) +
  302                                                sg->offset + sg->length,
  303                                                msg->msg_iov, len);
  304                         if (err)
  305                                 goto unlock;
  306 
  307                         sg->length += len;
  308                         ctx->merge = (sg->offset + sg->length) &
  309                                      (PAGE_SIZE - 1);
  310 
  311                         ctx->used += len;
  312                         copied += len;
  313                         size -= len;
  314                         continue;
  315                 }
  316 
  317                 if (!skcipher_writable(sk)) {
  318                         err = skcipher_wait_for_wmem(sk, msg->msg_flags);
  319                         if (err)
  320                                 goto unlock;
  321                 }
  322 
  323                 len = min_t(unsigned long, len, skcipher_sndbuf(sk));
  324 
  325                 err = skcipher_alloc_sgl(sk);
  326                 if (err)
  327                         goto unlock;
  328 
  329                 sgl = list_entry(ctx->tsgl.prev, struct skcipher_sg_list, list);
  330                 sg = sgl->sg;
  331                 do {
  332                         i = sgl->cur;
  333                         plen = min_t(int, len, PAGE_SIZE);
  334 
  335                         sg_assign_page(sg + i, alloc_page(GFP_KERNEL));
  336                         err = -ENOMEM;
  337                         if (!sg_page(sg + i))
  338                                 goto unlock;
  339 
  340                         err = memcpy_fromiovec(page_address(sg_page(sg + i)),
  341                                                msg->msg_iov, plen);
  342                         if (err) {
  343                                 __free_page(sg_page(sg + i));
  344                                 sg_assign_page(sg + i, NULL);
  345                                 goto unlock;
  346                         }
  347 
  348                         sg[i].length = plen;
  349                         len -= plen;
  350                         ctx->used += plen;
  351                         copied += plen;
  352                         size -= plen;
  353                         sgl->cur++;
  354                 } while (len && sgl->cur < MAX_SGL_ENTS);
  355 
  356                 ctx->merge = plen & (PAGE_SIZE - 1);
  357         }
  358 
  359         err = 0;
  360 
  361         ctx->more = msg->msg_flags & MSG_MORE;
  362         if (!ctx->more && !list_empty(&ctx->tsgl))
  363                 sgl = list_entry(ctx->tsgl.prev, struct skcipher_sg_list, list);
  364 
  365 unlock:
  366         skcipher_data_wakeup(sk);
  367         release_sock(sk);
  368 
  369         return copied ?: err;
  370 }
  371 
  372 static ssize_t skcipher_sendpage(struct socket *sock, struct page *page,
  373                                  int offset, size_t size, int flags)
  374 {
  375         struct sock *sk = sock->sk;
  376         struct alg_sock *ask = alg_sk(sk);
  377         struct skcipher_ctx *ctx = ask->private;
  378         struct skcipher_sg_list *sgl;
  379         int err = -EINVAL;
  380 
  381         lock_sock(sk);
  382         if (!ctx->more && ctx->used)
  383                 goto unlock;
  384 
  385         if (!size)
  386                 goto done;
  387 
  388         if (!skcipher_writable(sk)) {
  389                 err = skcipher_wait_for_wmem(sk, flags);
  390                 if (err)
  391                         goto unlock;
  392         }
  393 
  394         err = skcipher_alloc_sgl(sk);
  395         if (err)
  396                 goto unlock;
  397 
  398         ctx->merge = 0;
  399         sgl = list_entry(ctx->tsgl.prev, struct skcipher_sg_list, list);
  400 
  401         get_page(page);
  402         sg_set_page(sgl->sg + sgl->cur, page, size, offset);
  403         sgl->cur++;
  404         ctx->used += size;
  405 
  406 done:
  407         ctx->more = flags & MSG_MORE;
  408         if (!ctx->more && !list_empty(&ctx->tsgl))
  409                 sgl = list_entry(ctx->tsgl.prev, struct skcipher_sg_list, list);
  410 
  411 unlock:
  412         skcipher_data_wakeup(sk);
  413         release_sock(sk);
  414 
  415         return err ?: size;
  416 }
  417 
  418 static int skcipher_recvmsg(struct kiocb *unused, struct socket *sock,
  419                             struct msghdr *msg, size_t ignored, int flags)
  420 {
  421         struct sock *sk = sock->sk;
  422         struct alg_sock *ask = alg_sk(sk);
  423         struct skcipher_ctx *ctx = ask->private;
  424         unsigned bs = crypto_ablkcipher_blocksize(crypto_ablkcipher_reqtfm(
  425                 &ctx->req));
  426         struct skcipher_sg_list *sgl;
  427         struct scatterlist *sg;
  428         unsigned long iovlen;
  429         struct iovec *iov;
  430         int err = -EAGAIN;
  431         int used;
  432         long copied = 0;
  433 
  434         lock_sock(sk);
  435         for (iov = msg->msg_iov, iovlen = msg->msg_iovlen; iovlen > 0;
  436              iovlen--, iov++) {
  437                 unsigned long seglen = iov->iov_len;
  438                 char __user *from = iov->iov_base;
  439 
  440                 while (seglen) {
  441                         sgl = list_first_entry(&ctx->tsgl,
  442                                                struct skcipher_sg_list, list);
  443                         sg = sgl->sg;
  444 
  445                         while (!sg->length)
  446                                 sg++;
  447 
  448                         used = ctx->used;
  449                         if (!used) {
  450                                 err = skcipher_wait_for_data(sk, flags);
  451                                 if (err)
  452                                         goto unlock;
  453                         }
  454 
  455                         used = min_t(unsigned long, used, seglen);
  456 
  457                         used = af_alg_make_sg(&ctx->rsgl, from, used, 1);
  458                         err = used;
  459                         if (err < 0)
  460                                 goto unlock;
  461 
  462                         if (ctx->more || used < ctx->used)
  463                                 used -= used % bs;
  464 
  465                         err = -EINVAL;
  466                         if (!used)
  467                                 goto free;
  468 
  469                         ablkcipher_request_set_crypt(&ctx->req, sg,
  470                                                      ctx->rsgl.sg, used,
  471                                                      ctx->iv);
  472 
  473                         err = af_alg_wait_for_completion(
  474                                 ctx->enc ?
  475                                         crypto_ablkcipher_encrypt(&ctx->req) :
  476                                         crypto_ablkcipher_decrypt(&ctx->req),
  477                                 &ctx->completion);
  478 
  479 free:
  480                         af_alg_free_sg(&ctx->rsgl);
  481 
  482                         if (err)
  483                                 goto unlock;
  484 
  485                         copied += used;
  486                         from += used;
  487                         seglen -= used;
  488                         skcipher_pull_sgl(sk, used);
  489                 }
  490         }
  491 
  492         err = 0;
  493 
  494 unlock:
  495         skcipher_wmem_wakeup(sk);
  496         release_sock(sk);
  497 
  498         return copied ?: err;
  499 }
  500 
  501 
  502 static unsigned int skcipher_poll(struct file *file, struct socket *sock,
  503                                   poll_table *wait)
  504 {
  505         struct sock *sk = sock->sk;
  506         struct alg_sock *ask = alg_sk(sk);
  507         struct skcipher_ctx *ctx = ask->private;
  508         unsigned int mask;
  509 
  510         sock_poll_wait(file, sk_sleep(sk), wait);
  511         mask = 0;
  512 
  513         if (ctx->used)
  514                 mask |= POLLIN | POLLRDNORM;
  515 
  516         if (skcipher_writable(sk))
  517                 mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
  518 
  519         return mask;
  520 }
  521 
  522 static struct proto_ops algif_skcipher_ops = {
  523         .family         =       PF_ALG,
  524 
  525         .connect        =       sock_no_connect,
  526         .socketpair     =       sock_no_socketpair,
  527         .getname        =       sock_no_getname,
  528         .ioctl          =       sock_no_ioctl,
  529         .listen         =       sock_no_listen,
  530         .shutdown       =       sock_no_shutdown,
  531         .getsockopt     =       sock_no_getsockopt,
  532         .mmap           =       sock_no_mmap,
  533         .bind           =       sock_no_bind,
  534         .accept         =       sock_no_accept,
  535         .setsockopt     =       sock_no_setsockopt,
  536 
  537         .release        =       af_alg_release,
  538         .sendmsg        =       skcipher_sendmsg,
  539         .sendpage       =       skcipher_sendpage,
  540         .recvmsg        =       skcipher_recvmsg,
  541         .poll           =       skcipher_poll,
  542 };
  543 
  544 static void *skcipher_bind(const char *name, u32 type, u32 mask)
  545 {
  546         return crypto_alloc_ablkcipher(name, type, mask);
  547 }
  548 
  549 static void skcipher_release(void *private)
  550 {
  551         crypto_free_ablkcipher(private);
  552 }
  553 
  554 static int skcipher_setkey(void *private, const u8 *key, unsigned int keylen)
  555 {
  556         return crypto_ablkcipher_setkey(private, key, keylen);
  557 }
  558 
  559 static void skcipher_sock_destruct(struct sock *sk)
  560 {
  561         struct alg_sock *ask = alg_sk(sk);
  562         struct skcipher_ctx *ctx = ask->private;
  563         struct crypto_ablkcipher *tfm = crypto_ablkcipher_reqtfm(&ctx->req);
  564 
  565         skcipher_free_sgl(sk);
  566         sock_kfree_s(sk, ctx->iv, crypto_ablkcipher_ivsize(tfm));
  567         sock_kfree_s(sk, ctx, ctx->len);
  568         af_alg_release_parent(sk);
  569 }
  570 
  571 static int skcipher_accept_parent(void *private, struct sock *sk)
  572 {
  573         struct skcipher_ctx *ctx;
  574         struct alg_sock *ask = alg_sk(sk);
  575         unsigned int len = sizeof(*ctx) + crypto_ablkcipher_reqsize(private);
  576 
  577         ctx = sock_kmalloc(sk, len, GFP_KERNEL);
  578         if (!ctx)
  579                 return -ENOMEM;
  580 
  581         ctx->iv = sock_kmalloc(sk, crypto_ablkcipher_ivsize(private),
  582                                GFP_KERNEL);
  583         if (!ctx->iv) {
  584                 sock_kfree_s(sk, ctx, len);
  585                 return -ENOMEM;
  586         }
  587 
  588         memset(ctx->iv, 0, crypto_ablkcipher_ivsize(private));
  589 
  590         INIT_LIST_HEAD(&ctx->tsgl);
  591         ctx->len = len;
  592         ctx->used = 0;
  593         ctx->more = 0;
  594         ctx->merge = 0;
  595         ctx->enc = 0;
  596         af_alg_init_completion(&ctx->completion);
  597 
  598         ask->private = ctx;
  599 
  600         ablkcipher_request_set_tfm(&ctx->req, private);
  601         ablkcipher_request_set_callback(&ctx->req, CRYPTO_TFM_REQ_MAY_BACKLOG,
  602                                         af_alg_complete, &ctx->completion);
  603 
  604         sk->sk_destruct = skcipher_sock_destruct;
  605 
  606         return 0;
  607 }
  608 
  609 static const struct af_alg_type algif_type_skcipher = {
  610         .bind           =       skcipher_bind,
  611         .release        =       skcipher_release,
  612         .setkey         =       skcipher_setkey,
  613         .accept         =       skcipher_accept_parent,
  614         .ops            =       &algif_skcipher_ops,
  615         .name           =       "skcipher",
  616         .owner          =       THIS_MODULE
  617 };
  618 
  619 static int __init algif_skcipher_init(void)
  620 {
  621         return af_alg_register_type(&algif_type_skcipher);
  622 }
  623 
  624 static void __exit algif_skcipher_exit(void)
  625 {
  626         int err = af_alg_unregister_type(&algif_type_skcipher);
  627         BUG_ON(err);
  628 }
  629 
  630 module_init(algif_skcipher_init);
  631 module_exit(algif_skcipher_exit);
  632 MODULE_LICENSE("GPL");
Cache object: c3ce06504637d4a34af605796dbe102d
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FreeBSD/Linux Kernel Cross Reference sys/crypto/algif_skcipher.c

FreeBSD/Linux Kernel Cross Reference
sys/crypto/algif_skcipher.c
