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