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 <linux/atomic.h>
  22 #include <net/sock.h>
  23
  24 #include <crypto/aead.h>
  25 #include <crypto/skcipher.h>
  26
  27 #define ALG_MAX_PAGES                   16
  28
  29 struct crypto_async_request;
  30
  31 struct alg_sock {
  32         /* struct sock must be the first member of struct alg_sock */
  33         struct sock sk;
  34
  35         struct sock *parent;
  36
  37         atomic_t refcnt;
  38         atomic_t nokey_refcnt;
  39
  40         const struct af_alg_type *type;
  41         void *private;
  42 };
  43
  44 struct af_alg_completion {
  45         struct completion completion;
  46         int err;
  47 };
  48
  49 struct af_alg_control {
  50         struct af_alg_iv *iv;
  51         int op;
  52         unsigned int aead_assoclen;
  53 };
  54
  55 struct af_alg_type {
  56         void *(*bind)(const char *name, u32 type, u32 mask);
  57         void (*release)(void *private);
  58         int (*setkey)(void *private, const u8 *key, unsigned int keylen);
  59         int (*accept)(void *private, struct sock *sk);
  60         int (*accept_nokey)(void *private, struct sock *sk);
  61         int (*setauthsize)(void *private, unsigned int authsize);
  62
  63         struct proto_ops *ops;
  64         struct proto_ops *ops_nokey;
  65         struct module *owner;
  66         char name[14];
  67 };
  68
  69 struct af_alg_sgl {
  70         struct scatterlist sg[ALG_MAX_PAGES + 1];
  71         struct page *pages[ALG_MAX_PAGES];
  72         unsigned int npages;
  73 };
  74
  75 /* TX SGL entry */
  76 struct af_alg_tsgl {
  77         struct list_head list;
  78         unsigned int cur;               /* Last processed SG entry */
  79         struct scatterlist sg[0];       /* Array of SGs forming the SGL */
  80 };
  81
  82 #define MAX_SGL_ENTS ((4096 - sizeof(struct af_alg_tsgl)) / \
  83                       sizeof(struct scatterlist) - 1)
  84
  85 /* RX SGL entry */
  86 struct af_alg_rsgl {
  87         struct af_alg_sgl sgl;
  88         struct list_head list;
  89         size_t sg_num_bytes;            /* Bytes of data in that SGL */
  90 };
  91
  92 /**
  93  * struct af_alg_async_req - definition of crypto request
  94  * @iocb:               IOCB for AIO operations
  95  * @sk:                 Socket the request is associated with
  96  * @first_rsgl:         First RX SG
  97  * @last_rsgl:          Pointer to last RX SG
  98  * @rsgl_list:          Track RX SGs
  99  * @tsgl:               Private, per request TX SGL of buffers to process
 100  * @tsgl_entries:       Number of entries in priv. TX SGL
 101  * @outlen:             Number of output bytes generated by crypto op
 102  * @areqlen:            Length of this data structure
 103  * @cra_u:              Cipher request
 104  */
 105 struct af_alg_async_req {
 106         struct kiocb *iocb;
 107         struct sock *sk;
 108
 109         struct af_alg_rsgl first_rsgl;
 110         struct af_alg_rsgl *last_rsgl;
 111         struct list_head rsgl_list;
 112
 113         struct scatterlist *tsgl;
 114         unsigned int tsgl_entries;
 115
 116         unsigned int outlen;
 117         unsigned int areqlen;
 118
 119         union {
 120                 struct aead_request aead_req;
 121                 struct skcipher_request skcipher_req;
 122         } cra_u;
 123
 124         /* req ctx trails this struct */
 125 };
 126
 127 /**
 128  * struct af_alg_ctx - definition of the crypto context
 129  *
 130  * The crypto context tracks the input data during the lifetime of an AF_ALG
 131  * socket.
 132  *
 133  * @tsgl_list:          Link to TX SGL
 134  * @iv:                 IV for cipher operation
 135  * @aead_assoclen:      Length of AAD for AEAD cipher operations
 136  * @completion:         Work queue for synchronous operation
 137  * @used:               TX bytes sent to kernel. This variable is used to
 138  *                      ensure that user space cannot cause the kernel
 139  *                      to allocate too much memory in sendmsg operation.
 140  * @rcvused:            Total RX bytes to be filled by kernel. This variable
 141  *                      is used to ensure user space cannot cause the kernel
 142  *                      to allocate too much memory in a recvmsg operation.
 143  * @more:               More data to be expected from user space?
 144  * @merge:              Shall new data from user space be merged into existing
 145  *                      SG?
 146  * @enc:                Cryptographic operation to be performed when
 147  *                      recvmsg is invoked.
 148  * @len:                Length of memory allocated for this data structure.
 149  */
 150 struct af_alg_ctx {
 151         struct list_head tsgl_list;
 152
 153         void *iv;
 154         size_t aead_assoclen;
 155
 156         struct af_alg_completion completion;
 157
 158         size_t used;
 159         atomic_t rcvused;
 160
 161         bool more;
 162         bool merge;
 163         bool enc;
 164
 165         unsigned int len;
 166 };
 167
 168 int af_alg_register_type(const struct af_alg_type *type);
 169 int af_alg_unregister_type(const struct af_alg_type *type);
 170
 171 int af_alg_release(struct socket *sock);
 172 void af_alg_release_parent(struct sock *sk);
 173 int af_alg_accept(struct sock *sk, struct socket *newsock, bool kern);
 174
 175 int af_alg_make_sg(struct af_alg_sgl *sgl, struct iov_iter *iter, int len);
 176 void af_alg_free_sg(struct af_alg_sgl *sgl);
 177 void af_alg_link_sg(struct af_alg_sgl *sgl_prev, struct af_alg_sgl *sgl_new);
 178
 179 int af_alg_cmsg_send(struct msghdr *msg, struct af_alg_control *con);
 180
 181 int af_alg_wait_for_completion(int err, struct af_alg_completion *completion);
 182 void af_alg_complete(struct crypto_async_request *req, int err);
 183
 184 static inline struct alg_sock *alg_sk(struct sock *sk)
 185 {
 186         return (struct alg_sock *)sk;
 187 }
 188
 189 static inline void af_alg_init_completion(struct af_alg_completion *completion)
 190 {
 191         init_completion(&completion->completion);
 192 }
 193
 194 /**
 195  * Size of available buffer for sending data from user space to kernel.
 196  *
 197  * @sk socket of connection to user space
 198  * @return number of bytes still available
 199  */
 200 static inline int af_alg_sndbuf(struct sock *sk)
 201 {
 202         struct alg_sock *ask = alg_sk(sk);
 203         struct af_alg_ctx *ctx = ask->private;
 204
 205         return max_t(int, max_t(int, sk->sk_sndbuf & PAGE_MASK, PAGE_SIZE) -
 206                           ctx->used, 0);
 207 }
 208
 209 /**
 210  * Can the send buffer still be written to?
 211  *
 212  * @sk socket of connection to user space
 213  * @return true => writable, false => not writable
 214  */
 215 static inline bool af_alg_writable(struct sock *sk)
 216 {
 217         return PAGE_SIZE <= af_alg_sndbuf(sk);
 218 }
 219
 220 /**
 221  * Size of available buffer used by kernel for the RX user space operation.
 222  *
 223  * @sk socket of connection to user space
 224  * @return number of bytes still available
 225  */
 226 static inline int af_alg_rcvbuf(struct sock *sk)
 227 {
 228         struct alg_sock *ask = alg_sk(sk);
 229         struct af_alg_ctx *ctx = ask->private;
 230
 231         return max_t(int, max_t(int, sk->sk_rcvbuf & PAGE_MASK, PAGE_SIZE) -
 232                      atomic_read(&ctx->rcvused), 0);
 233 }
 234
 235 /**
 236  * Can the RX buffer still be written to?
 237  *
 238  * @sk socket of connection to user space
 239  * @return true => writable, false => not writable
 240  */
 241 static inline bool af_alg_readable(struct sock *sk)
 242 {
 243         return PAGE_SIZE <= af_alg_rcvbuf(sk);
 244 }
 245
 246 int af_alg_alloc_tsgl(struct sock *sk);
 247 unsigned int af_alg_count_tsgl(struct sock *sk, size_t bytes, size_t offset);
 248 void af_alg_pull_tsgl(struct sock *sk, size_t used, struct scatterlist *dst,
 249                       size_t dst_offset);
 250 void af_alg_free_areq_sgls(struct af_alg_async_req *areq);
 251 int af_alg_wait_for_wmem(struct sock *sk, unsigned int flags);
 252 void af_alg_wmem_wakeup(struct sock *sk);
 253 int af_alg_wait_for_data(struct sock *sk, unsigned flags);
 254 void af_alg_data_wakeup(struct sock *sk);
 255 int af_alg_sendmsg(struct socket *sock, struct msghdr *msg, size_t size,
 256                    unsigned int ivsize);
 257 ssize_t af_alg_sendpage(struct socket *sock, struct page *page,
 258                         int offset, size_t size, int flags);
 259 void af_alg_free_resources(struct af_alg_async_req *areq);
 260 void af_alg_async_cb(struct crypto_async_request *_req, int err);
 261 unsigned int af_alg_poll(struct file *file, struct socket *sock,
 262                          poll_table *wait);
 263 struct af_alg_async_req *af_alg_alloc_areq(struct sock *sk,
 264                                            unsigned int areqlen);
 265 int af_alg_get_rsgl(struct sock *sk, struct msghdr *msg, int flags,
 266                     struct af_alg_async_req *areq, size_t maxsize,
 267                     size_t *outlen);
 268
 269 #endif  /* _CRYPTO_IF_ALG_H */