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_completion {
  44         struct completion completion;
  45         int err;
  46 };
  47
  48 struct af_alg_control {
  49         struct af_alg_iv *iv;
  50         int op;
  51         unsigned int aead_assoclen;
  52 };
  53
  54 struct af_alg_type {
  55         void *(*bind)(const char *name, u32 type, u32 mask);
  56         void (*release)(void *private);
  57         int (*setkey)(void *private, const u8 *key, unsigned int keylen);
  58         int (*accept)(void *private, struct sock *sk);
  59         int (*accept_nokey)(void *private, struct sock *sk);
  60         int (*setauthsize)(void *private, unsigned int authsize);
  61
  62         struct proto_ops *ops;
  63         struct proto_ops *ops_nokey;
  64         struct module *owner;
  65         char name[14];
  66 };
  67
  68 struct af_alg_sgl {
  69         struct scatterlist sg[ALG_MAX_PAGES + 1];
  70         struct page *pages[ALG_MAX_PAGES];
  71         unsigned int npages;
  72 };
  73
  74 /* TX SGL entry */
  75 struct af_alg_tsgl {
  76         struct list_head list;
  77         unsigned int cur;               /* Last processed SG entry */
  78         struct scatterlist sg[0];       /* Array of SGs forming the SGL */
  79 };
  80
  81 #define MAX_SGL_ENTS ((4096 - sizeof(struct af_alg_tsgl)) / \
  82                       sizeof(struct scatterlist) - 1)
  83
  84 /* RX SGL entry */
  85 struct af_alg_rsgl {
  86         struct af_alg_sgl sgl;
  87         struct list_head list;
  88         size_t sg_num_bytes;            /* Bytes of data in that SGL */
  89 };
  90
  91 /**
  92  * struct af_alg_async_req - definition of crypto request
  93  * @iocb:               IOCB for AIO operations
  94  * @sk:                 Socket the request is associated with
  95  * @first_rsgl:         First RX SG
  96  * @last_rsgl:          Pointer to last RX SG
  97  * @rsgl_list:          Track RX SGs
  98  * @tsgl:               Private, per request TX SGL of buffers to process
  99  * @tsgl_entries:       Number of entries in priv. TX SGL
 100  * @outlen:             Number of output bytes generated by crypto op
 101  * @areqlen:            Length of this data structure
 102  * @cra_u:              Cipher request
 103  */
 104 struct af_alg_async_req {
 105         struct kiocb *iocb;
 106         struct sock *sk;
 107
 108         struct af_alg_rsgl first_rsgl;
 109         struct af_alg_rsgl *last_rsgl;
 110         struct list_head rsgl_list;
 111
 112         struct scatterlist *tsgl;
 113         unsigned int tsgl_entries;
 114
 115         unsigned int outlen;
 116         unsigned int areqlen;
 117
 118         union {
 119                 struct aead_request aead_req;
 120                 struct skcipher_request skcipher_req;
 121         } cra_u;
 122
 123         /* req ctx trails this struct */
 124 };
 125
 126 /**
 127  * struct af_alg_ctx - definition of the crypto context
 128  *
 129  * The crypto context tracks the input data during the lifetime of an AF_ALG
 130  * socket.
 131  *
 132  * @tsgl_list:          Link to TX SGL
 133  * @iv:                 IV for cipher operation
 134  * @aead_assoclen:      Length of AAD for AEAD cipher operations
 135  * @completion:         Work queue for synchronous operation
 136  * @used:               TX bytes sent to kernel. This variable is used to
 137  *                      ensure that user space cannot cause the kernel
 138  *                      to allocate too much memory in sendmsg operation.
 139  * @rcvused:            Total RX bytes to be filled by kernel. This variable
 140  *                      is used to ensure user space cannot cause the kernel
 141  *                      to allocate too much memory in a recvmsg operation.
 142  * @more:               More data to be expected from user space?
 143  * @merge:              Shall new data from user space be merged into existing
 144  *                      SG?
 145  * @enc:                Cryptographic operation to be performed when
 146  *                      recvmsg is invoked.
 147  * @len:                Length of memory allocated for this data structure.
 148  */
 149 struct af_alg_ctx {
 150         struct list_head tsgl_list;
 151
 152         void *iv;
 153         size_t aead_assoclen;
 154
 155         struct af_alg_completion completion;
 156
 157         size_t used;
 158         size_t rcvused;
 159
 160         bool more;
 161         bool merge;
 162         bool enc;
 163
 164         unsigned int len;
 165 };
 166
 167 int af_alg_register_type(const struct af_alg_type *type);
 168 int af_alg_unregister_type(const struct af_alg_type *type);
 169
 170 int af_alg_release(struct socket *sock);
 171 void af_alg_release_parent(struct sock *sk);
 172 int af_alg_accept(struct sock *sk, struct socket *newsock, bool kern);
 173
 174 int af_alg_make_sg(struct af_alg_sgl *sgl, struct iov_iter *iter, int len);
 175 void af_alg_free_sg(struct af_alg_sgl *sgl);
 176 void af_alg_link_sg(struct af_alg_sgl *sgl_prev, struct af_alg_sgl *sgl_new);
 177
 178 int af_alg_cmsg_send(struct msghdr *msg, struct af_alg_control *con);
 179
 180 int af_alg_wait_for_completion(int err, struct af_alg_completion *completion);
 181 void af_alg_complete(struct crypto_async_request *req, int err);
 182
 183 static inline struct alg_sock *alg_sk(struct sock *sk)
 184 {
 185         return (struct alg_sock *)sk;
 186 }
 187
 188 static inline void af_alg_init_completion(struct af_alg_completion *completion)
 189 {
 190         init_completion(&completion->completion);
 191 }
 192
 193 /**
 194  * Size of available buffer for sending data from user space to kernel.
 195  *
 196  * @sk socket of connection to user space
 197  * @return number of bytes still available
 198  */
 199 static inline int af_alg_sndbuf(struct sock *sk)
 200 {
 201         struct alg_sock *ask = alg_sk(sk);
 202         struct af_alg_ctx *ctx = ask->private;
 203
 204         return max_t(int, max_t(int, sk->sk_sndbuf & PAGE_MASK, PAGE_SIZE) -
 205                           ctx->used, 0);
 206 }
 207
 208 /**
 209  * Can the send buffer still be written to?
 210  *
 211  * @sk socket of connection to user space
 212  * @return true => writable, false => not writable
 213  */
 214 static inline bool af_alg_writable(struct sock *sk)
 215 {
 216         return PAGE_SIZE <= af_alg_sndbuf(sk);
 217 }
 218
 219 /**
 220  * Size of available buffer used by kernel for the RX user space operation.
 221  *
 222  * @sk socket of connection to user space
 223  * @return number of bytes still available
 224  */
 225 static inline int af_alg_rcvbuf(struct sock *sk)
 226 {
 227         struct alg_sock *ask = alg_sk(sk);
 228         struct af_alg_ctx *ctx = ask->private;
 229
 230         return max_t(int, max_t(int, sk->sk_rcvbuf & PAGE_MASK, PAGE_SIZE) -
 231                           ctx->rcvused, 0);
 232 }
 233
 234 /**
 235  * Can the RX buffer still be written to?
 236  *
 237  * @sk socket of connection to user space
 238  * @return true => writable, false => not writable
 239  */
 240 static inline bool af_alg_readable(struct sock *sk)
 241 {
 242         return PAGE_SIZE <= af_alg_rcvbuf(sk);
 243 }
 244
 245 int af_alg_alloc_tsgl(struct sock *sk);
 246 unsigned int af_alg_count_tsgl(struct sock *sk, size_t bytes, size_t offset);
 247 void af_alg_pull_tsgl(struct sock *sk, size_t used, struct scatterlist *dst,
 248                       size_t dst_offset);
 249 void af_alg_free_areq_sgls(struct af_alg_async_req *areq);
 250 int af_alg_wait_for_wmem(struct sock *sk, unsigned int flags);
 251 void af_alg_wmem_wakeup(struct sock *sk);
 252 int af_alg_wait_for_data(struct sock *sk, unsigned flags);
 253 void af_alg_data_wakeup(struct sock *sk);
 254 int af_alg_sendmsg(struct socket *sock, struct msghdr *msg, size_t size,
 255                    unsigned int ivsize);
 256 ssize_t af_alg_sendpage(struct socket *sock, struct page *page,
 257                         int offset, size_t size, int flags);
 258 void af_alg_free_resources(struct af_alg_async_req *areq);
 259 void af_alg_async_cb(struct crypto_async_request *_req, int err);
 260 unsigned int af_alg_poll(struct file *file, struct socket *sock,
 261                          poll_table *wait);
 262 struct af_alg_async_req *af_alg_alloc_areq(struct sock *sk,
 263                                            unsigned int areqlen);
 264 int af_alg_get_rsgl(struct sock *sk, struct msghdr *msg, int flags,
 265                     struct af_alg_async_req *areq, size_t maxsize,
 266                     size_t *outlen);
 267
 268 #endif  /* _CRYPTO_IF_ALG_H */