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); 172 173 static inline struct alg_sock *alg_sk(struct sock *sk) 174 { 175 return (struct alg_sock *)sk; 176 } 177 178 /** 179 * Size of available buffer for sending data from user space to kernel. 180 * 181 * @sk socket of connection to user space 182 * @return number of bytes still available 183 */ 184 static inline int af_alg_sndbuf(struct sock *sk) 185 { 186 struct alg_sock *ask = alg_sk(sk); 187 struct af_alg_ctx *ctx = ask->private; 188 189 return max_t(int, max_t(int, sk->sk_sndbuf & PAGE_MASK, PAGE_SIZE) - 190 ctx->used, 0); 191 } 192 193 /** 194 * Can the send buffer still be written to? 195 * 196 * @sk socket of connection to user space 197 * @return true => writable, false => not writable 198 */ 199 static inline bool af_alg_writable(struct sock *sk) 200 { 201 return PAGE_SIZE <= af_alg_sndbuf(sk); 202 } 203 204 /** 205 * Size of available buffer used by kernel for the RX user space operation. 206 * 207 * @sk socket of connection to user space 208 * @return number of bytes still available 209 */ 210 static inline int af_alg_rcvbuf(struct sock *sk) 211 { 212 struct alg_sock *ask = alg_sk(sk); 213 struct af_alg_ctx *ctx = ask->private; 214 215 return max_t(int, max_t(int, sk->sk_rcvbuf & PAGE_MASK, PAGE_SIZE) - 216 atomic_read(&ctx->rcvused), 0); 217 } 218 219 /** 220 * Can the RX buffer still be written to? 221 * 222 * @sk socket of connection to user space 223 * @return true => writable, false => not writable 224 */ 225 static inline bool af_alg_readable(struct sock *sk) 226 { 227 return PAGE_SIZE <= af_alg_rcvbuf(sk); 228 } 229 230 unsigned int af_alg_count_tsgl(struct sock *sk, size_t bytes, size_t offset); 231 void af_alg_pull_tsgl(struct sock *sk, size_t used, struct scatterlist *dst, 232 size_t dst_offset); 233 void af_alg_wmem_wakeup(struct sock *sk); 234 int af_alg_wait_for_data(struct sock *sk, unsigned flags); 235 int af_alg_sendmsg(struct socket *sock, struct msghdr *msg, size_t size, 236 unsigned int ivsize); 237 ssize_t af_alg_sendpage(struct socket *sock, struct page *page, 238 int offset, size_t size, int flags); 239 void af_alg_free_resources(struct af_alg_async_req *areq); 240 void af_alg_async_cb(struct crypto_async_request *_req, int err); 241 __poll_t af_alg_poll(struct file *file, struct socket *sock, 242 poll_table *wait); 243 struct af_alg_async_req *af_alg_alloc_areq(struct sock *sk, 244 unsigned int areqlen); 245 int af_alg_get_rsgl(struct sock *sk, struct msghdr *msg, int flags, 246 struct af_alg_async_req *areq, size_t maxsize, 247 size_t *outlen); 248 249 #endif /* _CRYPTO_IF_ALG_H */ 250