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