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 alg_sock {
  25         /* struct sock must be the first member of struct alg_sock */
  26         struct sock sk;
  27
  28         struct sock *parent;
  29
  30         atomic_t refcnt;
  31         atomic_t nokey_refcnt;
  32
  33         const struct af_alg_type *type;
  34         void *private;
  35 };
  36
  37 struct af_alg_control {
  38         struct af_alg_iv *iv;
  39         int op;
  40         unsigned int aead_assoclen;
  41 };
  42
  43 struct af_alg_type {
  44         void *(*bind)(const char *name, u32 type, u32 mask);
  45         void (*release)(void *private);
  46         int (*setkey)(void *private, const u8 *key, unsigned int keylen);
  47         int (*setentropy)(void *private, sockptr_t entropy, unsigned int len);
  48         int (*accept)(void *private, struct sock *sk);
  49         int (*accept_nokey)(void *private, struct sock *sk);
  50         int (*setauthsize)(void *private, unsigned int authsize);
  51
  52         struct proto_ops *ops;
  53         struct proto_ops *ops_nokey;
  54         struct module *owner;
  55         char name[14];
  56 };
  57
  58 struct af_alg_sgl {
  59         struct sg_table sgt;
  60         struct scatterlist sgl[ALG_MAX_PAGES + 1];
  61         bool need_unpin;
  62 };
  63
  64 /* TX SGL entry */
  65 struct af_alg_tsgl {
  66         struct list_head list;
  67         unsigned int cur;               /* Last processed SG entry */
  68         struct scatterlist sg[];        /* Array of SGs forming the SGL */
  69 };
  70
  71 #define MAX_SGL_ENTS ((4096 - sizeof(struct af_alg_tsgl)) / \
  72                       sizeof(struct scatterlist) - 1)
  73
  74 /* RX SGL entry */
  75 struct af_alg_rsgl {
  76         struct af_alg_sgl sgl;
  77         struct list_head list;
  78         size_t sg_num_bytes;            /* Bytes of data in that SGL */
  79 };
  80
  81 /**
  82  * struct af_alg_async_req - definition of crypto request
  83  * @iocb:               IOCB for AIO operations
  84  * @sk:                 Socket the request is associated with
  85  * @first_rsgl:         First RX SG
  86  * @last_rsgl:          Pointer to last RX SG
  87  * @rsgl_list:          Track RX SGs
  88  * @tsgl:               Private, per request TX SGL of buffers to process
  89  * @tsgl_entries:       Number of entries in priv. TX SGL
  90  * @outlen:             Number of output bytes generated by crypto op
  91  * @areqlen:            Length of this data structure
  92  * @cra_u:              Cipher request
  93  */
  94 struct af_alg_async_req {
  95         struct kiocb *iocb;
  96         struct sock *sk;
  97
  98         struct af_alg_rsgl first_rsgl;
  99         struct af_alg_rsgl *last_rsgl;
 100         struct list_head rsgl_list;
 101
 102         struct scatterlist *tsgl;
 103         unsigned int tsgl_entries;
 104
 105         unsigned int outlen;
 106         unsigned int areqlen;
 107
 108         union {
 109                 struct aead_request aead_req;
 110                 struct skcipher_request skcipher_req;
 111         } cra_u;
 112
 113         /* req ctx trails this struct */
 114 };
 115
 116 /**
 117  * struct af_alg_ctx - definition of the crypto context
 118  *
 119  * The crypto context tracks the input data during the lifetime of an AF_ALG
 120  * socket.
 121  *
 122  * @tsgl_list:          Link to TX SGL
 123  * @iv:                 IV for cipher operation
 124  * @state:              Existing state for continuing 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  * @init:               True if metadata has been sent.
 139  * @len:                Length of memory allocated for this data structure.
 140  * @inflight:           Non-zero when AIO requests are in flight.
 141  */
 142 struct af_alg_ctx {
 143         struct list_head tsgl_list;
 144
 145         void *iv;
 146         void *state;
 147         size_t aead_assoclen;
 148
 149         struct crypto_wait wait;
 150
 151         size_t used;
 152         atomic_t rcvused;
 153
 154         bool more;
 155         bool merge;
 156         bool enc;
 157         bool init;
 158
 159         unsigned int len;
 160
 161         unsigned int inflight;
 162 };
 163
 164 int af_alg_register_type(const struct af_alg_type *type);
 165 int af_alg_unregister_type(const struct af_alg_type *type);
 166
 167 int af_alg_release(struct socket *sock);
 168 void af_alg_release_parent(struct sock *sk);
 169 int af_alg_accept(struct sock *sk, struct socket *newsock,
 170                   struct proto_accept_arg *arg);
 171
 172 void af_alg_free_sg(struct af_alg_sgl *sgl);
 173
 174 static inline struct alg_sock *alg_sk(struct sock *sk)
 175 {
 176         return (struct alg_sock *)sk;
 177 }
 178
 179 /**
 180  * Size of available buffer for sending data from user space to kernel.
 181  *
 182  * @sk socket of connection to user space
 183  * @return number of bytes still available
 184  */
 185 static inline int af_alg_sndbuf(struct sock *sk)
 186 {
 187         struct alg_sock *ask = alg_sk(sk);
 188         struct af_alg_ctx *ctx = ask->private;
 189
 190         return max_t(int, max_t(int, sk->sk_sndbuf & PAGE_MASK, PAGE_SIZE) -
 191                           ctx->used, 0);
 192 }
 193
 194 /**
 195  * Can the send buffer still be written to?
 196  *
 197  * @sk socket of connection to user space
 198  * @return true => writable, false => not writable
 199  */
 200 static inline bool af_alg_writable(struct sock *sk)
 201 {
 202         return PAGE_SIZE <= af_alg_sndbuf(sk);
 203 }
 204
 205 /**
 206  * Size of available buffer used by kernel for the RX user space operation.
 207  *
 208  * @sk socket of connection to user space
 209  * @return number of bytes still available
 210  */
 211 static inline int af_alg_rcvbuf(struct sock *sk)
 212 {
 213         struct alg_sock *ask = alg_sk(sk);
 214         struct af_alg_ctx *ctx = ask->private;
 215
 216         return max_t(int, max_t(int, sk->sk_rcvbuf & PAGE_MASK, PAGE_SIZE) -
 217                      atomic_read(&ctx->rcvused), 0);
 218 }
 219
 220 /**
 221  * Can the RX buffer still be written to?
 222  *
 223  * @sk socket of connection to user space
 224  * @return true => writable, false => not writable
 225  */
 226 static inline bool af_alg_readable(struct sock *sk)
 227 {
 228         return PAGE_SIZE <= af_alg_rcvbuf(sk);
 229 }
 230
 231 unsigned int af_alg_count_tsgl(struct sock *sk, size_t bytes, size_t offset);
 232 void af_alg_pull_tsgl(struct sock *sk, size_t used, struct scatterlist *dst,
 233                       size_t dst_offset);
 234 void af_alg_wmem_wakeup(struct sock *sk);
 235 int af_alg_wait_for_data(struct sock *sk, unsigned flags, unsigned min);
 236 int af_alg_sendmsg(struct socket *sock, struct msghdr *msg, size_t size,
 237                    unsigned int ivsize);
 238 void af_alg_free_resources(struct af_alg_async_req *areq);
 239 void af_alg_async_cb(void *data, int err);
 240 __poll_t af_alg_poll(struct file *file, struct socket *sock,
 241                          poll_table *wait);
 242 struct af_alg_async_req *af_alg_alloc_areq(struct sock *sk,
 243                                            unsigned int areqlen);
 244 int af_alg_get_rsgl(struct sock *sk, struct msghdr *msg, int flags,
 245                     struct af_alg_async_req *areq, size_t maxsize,
 246                     size_t *outlen);
 247
 248 #endif  /* _CRYPTO_IF_ALG_H */