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