include/crypto/if_alg.h

   1 /* SPDX-License-Identifier: GPL-2.0-or-later */
   2 /*
   3  * if_alg: User-space algorithm interface
   4  *
   5  * Copyright (c) 2010 Herbert Xu <herbert@gondor.apana.org.au>
   6  */
   7
   8 #ifndef _CRYPTO_IF_ALG_H
   9 #define _CRYPTO_IF_ALG_H
  10
  11 #include <linux/compiler.h>
  12 #include <linux/completion.h>
  13 #include <linux/if_alg.h>
  14 #include <linux/scatterlist.h>
  15 #include <linux/types.h>
  16 #include <linux/atomic.h>
  17 #include <net/sock.h>
  18
  19 #include <crypto/aead.h>
  20 #include <crypto/skcipher.h>
  21
  22 #define ALG_MAX_PAGES                   16
  23
  24 struct crypto_async_request;
  25
  26 struct alg_sock {
  27         /* struct sock must be the first member of struct alg_sock */
  28         struct sock sk;
  29
  30         struct sock *parent;
  31
  32         unsigned int refcnt;
  33         unsigned int nokey_refcnt;
  34
  35         const struct af_alg_type *type;
  36         void *private;
  37 };
  38
  39 struct af_alg_control {
  40         struct af_alg_iv *iv;
  41         int op;
  42         unsigned int aead_assoclen;
  43 };
  44
  45 struct af_alg_type {
  46         void *(*bind)(const char *name, u32 type, u32 mask);
  47         void (*release)(void *private);
  48         int (*setkey)(void *private, const u8 *key, unsigned int keylen);
  49         int (*accept)(void *private, struct sock *sk);
  50         int (*accept_nokey)(void *private, struct sock *sk);
  51         int (*setauthsize)(void *private, unsigned int authsize);
  52
  53         struct proto_ops *ops;
  54         struct proto_ops *ops_nokey;
  55         struct module *owner;
  56         char name[14];
  57 };
  58
  59 struct af_alg_sgl {
  60         struct scatterlist sg[ALG_MAX_PAGES + 1];
  61         struct page *pages[ALG_MAX_PAGES];
  62         unsigned int npages;
  63 };
  64
  65 /* TX SGL entry */
  66 struct af_alg_tsgl {
  67         struct list_head list;
  68         unsigned int cur;               /* Last processed SG entry */
  69         struct scatterlist sg[0];       /* Array of SGs forming the SGL */
  70 };
  71
  72 #define MAX_SGL_ENTS ((4096 - sizeof(struct af_alg_tsgl)) / \
  73                       sizeof(struct scatterlist) - 1)
  74
  75 /* RX SGL entry */
  76 struct af_alg_rsgl {
  77         struct af_alg_sgl sgl;
  78         struct list_head list;
  79         size_t sg_num_bytes;            /* Bytes of data in that SGL */
  80 };
  81
  82 /**
  83  * struct af_alg_async_req - definition of crypto request
  84  * @iocb:               IOCB for AIO operations
  85  * @sk:                 Socket the request is associated with
  86  * @first_rsgl:         First RX SG
  87  * @last_rsgl:          Pointer to last RX SG
  88  * @rsgl_list:          Track RX SGs
  89  * @tsgl:               Private, per request TX SGL of buffers to process
  90  * @tsgl_entries:       Number of entries in priv. TX SGL
  91  * @outlen:             Number of output bytes generated by crypto op
  92  * @areqlen:            Length of this data structure
  93  * @cra_u:              Cipher request
  94  */
  95 struct af_alg_async_req {
  96         struct kiocb *iocb;
  97         struct sock *sk;
  98
  99         struct af_alg_rsgl first_rsgl;
 100         struct af_alg_rsgl *last_rsgl;
 101         struct list_head rsgl_list;
 102
 103         struct scatterlist *tsgl;
 104         unsigned int tsgl_entries;
 105
 106         unsigned int outlen;
 107         unsigned int areqlen;
 108
 109         union {
 110                 struct aead_request aead_req;
 111                 struct skcipher_request skcipher_req;
 112         } cra_u;
 113
 114         /* req ctx trails this struct */
 115 };
 116
 117 /**
 118  * struct af_alg_ctx - definition of the crypto context
 119  *
 120  * The crypto context tracks the input data during the lifetime of an AF_ALG
 121  * socket.
 122  *
 123  * @tsgl_list:          Link to TX SGL
 124  * @iv:                 IV for cipher operation
 125  * @aead_assoclen:      Length of AAD for AEAD cipher operations
 126  * @completion:         Work queue for synchronous operation
 127  * @used:               TX bytes sent to kernel. This variable is used to
 128  *                      ensure that user space cannot cause the kernel
 129  *                      to allocate too much memory in sendmsg operation.
 130  * @rcvused:            Total RX bytes to be filled by kernel. This variable
 131  *                      is used to ensure user space cannot cause the kernel
 132  *                      to allocate too much memory in a recvmsg operation.
 133  * @more:               More data to be expected from user space?
 134  * @merge:              Shall new data from user space be merged into existing
 135  *                      SG?
 136  * @enc:                Cryptographic operation to be performed when
 137  *                      recvmsg is invoked.
 138  * @len:                Length of memory allocated for this data structure.
 139  */
 140 struct af_alg_ctx {
 141         struct list_head tsgl_list;
 142
 143         void *iv;
 144         size_t aead_assoclen;
 145
 146         struct crypto_wait wait;
 147
 148         size_t used;
 149         atomic_t rcvused;
 150
 151         bool more;
 152         bool merge;
 153         bool enc;
 154
 155         unsigned int len;
 156 };
 157
 158 int af_alg_register_type(const struct af_alg_type *type);
 159 int af_alg_unregister_type(const struct af_alg_type *type);
 160
 161 int af_alg_release(struct socket *sock);
 162 void af_alg_release_parent(struct sock *sk);
 163 int af_alg_accept(struct sock *sk, struct socket *newsock, bool kern);
 164
 165 int af_alg_make_sg(struct af_alg_sgl *sgl, struct iov_iter *iter, int len);
 166 void af_alg_free_sg(struct af_alg_sgl *sgl);
 167
 168 static inline struct alg_sock *alg_sk(struct sock *sk)
 169 {
 170         return (struct alg_sock *)sk;
 171 }
 172
 173 /**
 174  * Size of available buffer for sending data from user space to kernel.
 175  *
 176  * @sk socket of connection to user space
 177  * @return number of bytes still available
 178  */
 179 static inline int af_alg_sndbuf(struct sock *sk)
 180 {
 181         struct alg_sock *ask = alg_sk(sk);
 182         struct af_alg_ctx *ctx = ask->private;
 183
 184         return max_t(int, max_t(int, sk->sk_sndbuf & PAGE_MASK, PAGE_SIZE) -
 185                           ctx->used, 0);
 186 }
 187
 188 /**
 189  * Can the send buffer still be written to?
 190  *
 191  * @sk socket of connection to user space
 192  * @return true => writable, false => not writable
 193  */
 194 static inline bool af_alg_writable(struct sock *sk)
 195 {
 196         return PAGE_SIZE <= af_alg_sndbuf(sk);
 197 }
 198
 199 /**
 200  * Size of available buffer used by kernel for the RX user space operation.
 201  *
 202  * @sk socket of connection to user space
 203  * @return number of bytes still available
 204  */
 205 static inline int af_alg_rcvbuf(struct sock *sk)
 206 {
 207         struct alg_sock *ask = alg_sk(sk);
 208         struct af_alg_ctx *ctx = ask->private;
 209
 210         return max_t(int, max_t(int, sk->sk_rcvbuf & PAGE_MASK, PAGE_SIZE) -
 211                      atomic_read(&ctx->rcvused), 0);
 212 }
 213
 214 /**
 215  * Can the RX buffer still be written to?
 216  *
 217  * @sk socket of connection to user space
 218  * @return true => writable, false => not writable
 219  */
 220 static inline bool af_alg_readable(struct sock *sk)
 221 {
 222         return PAGE_SIZE <= af_alg_rcvbuf(sk);
 223 }
 224
 225 unsigned int af_alg_count_tsgl(struct sock *sk, size_t bytes, size_t offset);
 226 void af_alg_pull_tsgl(struct sock *sk, size_t used, struct scatterlist *dst,
 227                       size_t dst_offset);
 228 void af_alg_wmem_wakeup(struct sock *sk);
 229 int af_alg_wait_for_data(struct sock *sk, unsigned flags);
 230 int af_alg_sendmsg(struct socket *sock, struct msghdr *msg, size_t size,
 231                    unsigned int ivsize);
 232 ssize_t af_alg_sendpage(struct socket *sock, struct page *page,
 233                         int offset, size_t size, int flags);
 234 void af_alg_free_resources(struct af_alg_async_req *areq);
 235 void af_alg_async_cb(struct crypto_async_request *_req, int err);
 236 __poll_t af_alg_poll(struct file *file, struct socket *sock,
 237                          poll_table *wait);
 238 struct af_alg_async_req *af_alg_alloc_areq(struct sock *sk,
 239                                            unsigned int areqlen);
 240 int af_alg_get_rsgl(struct sock *sk, struct msghdr *msg, int flags,
 241                     struct af_alg_async_req *areq, size_t maxsize,
 242                     size_t *outlen);
 243
 244 #endif  /* _CRYPTO_IF_ALG_H */