include/crypto/if_alg.h

   1 /*
   2  * if_alg: User-space algorithm interface
   3  *
   4  * Copyright (c) 2010 Herbert Xu <herbert@gondor.apana.org.au>
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License as published by the Free
   8  * Software Foundation; either version 2 of the License, or (at your option)
   9  * any later version.
  10  *
  11  */
  12
  13 #ifndef _CRYPTO_IF_ALG_H
  14 #define _CRYPTO_IF_ALG_H
  15
  16 #include <linux/compiler.h>
  17 #include <linux/completion.h>
  18 #include <linux/if_alg.h>
  19 #include <linux/scatterlist.h>
  20 #include <linux/types.h>
  21 #include <net/sock.h>
  22
  23 #include <crypto/aead.h>
  24 #include <crypto/skcipher.h>
  25
  26 #define ALG_MAX_PAGES                   16
  27
  28 struct crypto_async_request;
  29
  30 struct alg_sock {
  31         /* struct sock must be the first member of struct alg_sock */
  32         struct sock sk;
  33
  34         struct sock *parent;
  35
  36         unsigned int refcnt;
  37         unsigned int nokey_refcnt;
  38
  39         const struct af_alg_type *type;
  40         void *private;
  41 };
  42
  43 struct af_alg_control {
  44         struct af_alg_iv *iv;
  45         int op;
  46         unsigned int aead_assoclen;
  47 };
  48
  49 struct af_alg_type {
  50         void *(*bind)(const char *name, u32 type, u32 mask);
  51         void (*release)(void *private);
  52         int (*setkey)(void *private, const u8 *key, unsigned int keylen);
  53         int (*accept)(void *private, struct sock *sk);
  54         int (*accept_nokey)(void *private, struct sock *sk);
  55         int (*setauthsize)(void *private, unsigned int authsize);
  56
  57         struct proto_ops *ops;
  58         struct proto_ops *ops_nokey;
  59         struct module *owner;
  60         char name[14];
  61 };
  62
  63 struct af_alg_sgl {
  64         struct scatterlist sg[ALG_MAX_PAGES + 1];
  65         struct page *pages[ALG_MAX_PAGES];
  66         unsigned int npages;
  67 };
  68
  69 /* TX SGL entry */
  70 struct af_alg_tsgl {
  71         struct list_head list;
  72         unsigned int cur;               /* Last processed SG entry */
  73         struct scatterlist sg[0];       /* Array of SGs forming the SGL */
  74 };
  75
  76 #define MAX_SGL_ENTS ((4096 - sizeof(struct af_alg_tsgl)) / \
  77                       sizeof(struct scatterlist) - 1)
  78
  79 /* RX SGL entry */
  80 struct af_alg_rsgl {
  81         struct af_alg_sgl sgl;
  82         struct list_head list;
  83         size_t sg_num_bytes;            /* Bytes of data in that SGL */
  84 };
  85
  86 /**
  87  * struct af_alg_async_req - definition of crypto request
  88  * @iocb:               IOCB for AIO operations
  89  * @sk:                 Socket the request is associated with
  90  * @first_rsgl:         First RX SG
  91  * @last_rsgl:          Pointer to last RX SG
  92  * @rsgl_list:          Track RX SGs
  93  * @tsgl:               Private, per request TX SGL of buffers to process
  94  * @tsgl_entries:       Number of entries in priv. TX SGL
  95  * @outlen:             Number of output bytes generated by crypto op
  96  * @areqlen:            Length of this data structure
  97  * @cra_u:              Cipher request
  98  */
  99 struct af_alg_async_req {
 100         struct kiocb *iocb;
 101         struct sock *sk;
 102
 103         struct af_alg_rsgl first_rsgl;
 104         struct af_alg_rsgl *last_rsgl;
 105         struct list_head rsgl_list;
 106
 107         struct scatterlist *tsgl;
 108         unsigned int tsgl_entries;
 109
 110         unsigned int outlen;
 111         unsigned int areqlen;
 112
 113         union {
 114                 struct aead_request aead_req;
 115                 struct skcipher_request skcipher_req;
 116         } cra_u;
 117
 118         /* req ctx trails this struct */
 119 };
 120
 121 /**
 122  * struct af_alg_ctx - definition of the crypto context
 123  *
 124  * The crypto context tracks the input data during the lifetime of an AF_ALG
 125  * socket.
 126  *
 127  * @tsgl_list:          Link to TX SGL
 128  * @iv:                 IV for cipher operation
 129  * @aead_assoclen:      Length of AAD for AEAD cipher operations
 130  * @completion:         Work queue for synchronous operation
 131  * @used:               TX bytes sent to kernel. This variable is used to
 132  *                      ensure that user space cannot cause the kernel
 133  *                      to allocate too much memory in sendmsg operation.
 134  * @rcvused:            Total RX bytes to be filled by kernel. This variable
 135  *                      is used to ensure user space cannot cause the kernel
 136  *                      to allocate too much memory in a recvmsg operation.
 137  * @more:               More data to be expected from user space?
 138  * @merge:              Shall new data from user space be merged into existing
 139  *                      SG?
 140  * @enc:                Cryptographic operation to be performed when
 141  *                      recvmsg is invoked.
 142  * @len:                Length of memory allocated for this data structure.
 143  */
 144 struct af_alg_ctx {
 145         struct list_head tsgl_list;
 146
 147         void *iv;
 148         size_t aead_assoclen;
 149
 150         struct crypto_wait wait;
 151
 152         size_t used;
 153         size_t rcvused;
 154
 155         bool more;
 156         bool merge;
 157         bool enc;
 158
 159         unsigned int len;
 160 };
 161
 162 int af_alg_register_type(const struct af_alg_type *type);
 163 int af_alg_unregister_type(const struct af_alg_type *type);
 164
 165 int af_alg_release(struct socket *sock);
 166 void af_alg_release_parent(struct sock *sk);
 167 int af_alg_accept(struct sock *sk, struct socket *newsock, bool kern);
 168
 169 int af_alg_make_sg(struct af_alg_sgl *sgl, struct iov_iter *iter, int len);
 170 void af_alg_free_sg(struct af_alg_sgl *sgl);
 171 void af_alg_link_sg(struct af_alg_sgl *sgl_prev, struct af_alg_sgl *sgl_new);
 172
 173 int af_alg_cmsg_send(struct msghdr *msg, struct af_alg_control *con);
 174
 175 static inline struct alg_sock *alg_sk(struct sock *sk)
 176 {
 177         return (struct alg_sock *)sk;
 178 }
 179
 180 /**
 181  * Size of available buffer for sending data from user space to kernel.
 182  *
 183  * @sk socket of connection to user space
 184  * @return number of bytes still available
 185  */
 186 static inline int af_alg_sndbuf(struct sock *sk)
 187 {
 188         struct alg_sock *ask = alg_sk(sk);
 189         struct af_alg_ctx *ctx = ask->private;
 190
 191         return max_t(int, max_t(int, sk->sk_sndbuf & PAGE_MASK, PAGE_SIZE) -
 192                           ctx->used, 0);
 193 }
 194
 195 /**
 196  * Can the send buffer still be written to?
 197  *
 198  * @sk socket of connection to user space
 199  * @return true => writable, false => not writable
 200  */
 201 static inline bool af_alg_writable(struct sock *sk)
 202 {
 203         return PAGE_SIZE <= af_alg_sndbuf(sk);
 204 }
 205
 206 /**
 207  * Size of available buffer used by kernel for the RX user space operation.
 208  *
 209  * @sk socket of connection to user space
 210  * @return number of bytes still available
 211  */
 212 static inline int af_alg_rcvbuf(struct sock *sk)
 213 {
 214         struct alg_sock *ask = alg_sk(sk);
 215         struct af_alg_ctx *ctx = ask->private;
 216
 217         return max_t(int, max_t(int, sk->sk_rcvbuf & PAGE_MASK, PAGE_SIZE) -
 218                           ctx->rcvused, 0);
 219 }
 220
 221 /**
 222  * Can the RX buffer still be written to?
 223  *
 224  * @sk socket of connection to user space
 225  * @return true => writable, false => not writable
 226  */
 227 static inline bool af_alg_readable(struct sock *sk)
 228 {
 229         return PAGE_SIZE <= af_alg_rcvbuf(sk);
 230 }
 231
 232 int af_alg_alloc_tsgl(struct sock *sk);
 233 unsigned int af_alg_count_tsgl(struct sock *sk, size_t bytes, size_t offset);
 234 void af_alg_pull_tsgl(struct sock *sk, size_t used, struct scatterlist *dst,
 235                       size_t dst_offset);
 236 void af_alg_free_areq_sgls(struct af_alg_async_req *areq);
 237 int af_alg_wait_for_wmem(struct sock *sk, unsigned int flags);
 238 void af_alg_wmem_wakeup(struct sock *sk);
 239 int af_alg_wait_for_data(struct sock *sk, unsigned flags);
 240 void af_alg_data_wakeup(struct sock *sk);
 241 int af_alg_sendmsg(struct socket *sock, struct msghdr *msg, size_t size,
 242                    unsigned int ivsize);
 243 ssize_t af_alg_sendpage(struct socket *sock, struct page *page,
 244                         int offset, size_t size, int flags);
 245 void af_alg_free_resources(struct af_alg_async_req *areq);
 246 void af_alg_async_cb(struct crypto_async_request *_req, int err);
 247 unsigned int af_alg_poll(struct file *file, struct socket *sock,
 248                          poll_table *wait);
 249 struct af_alg_async_req *af_alg_alloc_areq(struct sock *sk,
 250                                            unsigned int areqlen);
 251 int af_alg_get_rsgl(struct sock *sk, struct msghdr *msg, int flags,
 252                     struct af_alg_async_req *areq, size_t maxsize,
 253                     size_t *outlen);
 254
 255 #endif  /* _CRYPTO_IF_ALG_H */