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 void af_alg_link_sg(struct af_alg_sgl *sgl_prev, struct af_alg_sgl *sgl_new);
173
174 int af_alg_cmsg_send(struct msghdr *msg, struct af_alg_control *con);
175
alg_sk(struct sock * sk)176 static inline struct alg_sock *alg_sk(struct sock *sk)
177 {
178 return (struct alg_sock *)sk;
179 }
180
181 /**
182 * Size of available buffer for sending data from user space to kernel.
183 *
184 * @sk socket of connection to user space
185 * @return number of bytes still available
186 */
af_alg_sndbuf(struct sock * sk)187 static inline int af_alg_sndbuf(struct sock *sk)
188 {
189 struct alg_sock *ask = alg_sk(sk);
190 struct af_alg_ctx *ctx = ask->private;
191
192 return max_t(int, max_t(int, sk->sk_sndbuf & PAGE_MASK, PAGE_SIZE) -
193 ctx->used, 0);
194 }
195
196 /**
197 * Can the send buffer still be written to?
198 *
199 * @sk socket of connection to user space
200 * @return true => writable, false => not writable
201 */
af_alg_writable(struct sock * sk)202 static inline bool af_alg_writable(struct sock *sk)
203 {
204 return PAGE_SIZE <= af_alg_sndbuf(sk);
205 }
206
207 /**
208 * Size of available buffer used by kernel for the RX user space operation.
209 *
210 * @sk socket of connection to user space
211 * @return number of bytes still available
212 */
af_alg_rcvbuf(struct sock * sk)213 static inline int af_alg_rcvbuf(struct sock *sk)
214 {
215 struct alg_sock *ask = alg_sk(sk);
216 struct af_alg_ctx *ctx = ask->private;
217
218 return max_t(int, max_t(int, sk->sk_rcvbuf & PAGE_MASK, PAGE_SIZE) -
219 atomic_read(&ctx->rcvused), 0);
220 }
221
222 /**
223 * Can the RX buffer still be written to?
224 *
225 * @sk socket of connection to user space
226 * @return true => writable, false => not writable
227 */
af_alg_readable(struct sock * sk)228 static inline bool af_alg_readable(struct sock *sk)
229 {
230 return PAGE_SIZE <= af_alg_rcvbuf(sk);
231 }
232
233 int af_alg_alloc_tsgl(struct sock *sk);
234 unsigned int af_alg_count_tsgl(struct sock *sk, size_t bytes, size_t offset);
235 void af_alg_pull_tsgl(struct sock *sk, size_t used, struct scatterlist *dst,
236 size_t dst_offset);
237 void af_alg_free_areq_sgls(struct af_alg_async_req *areq);
238 int af_alg_wait_for_wmem(struct sock *sk, unsigned int flags);
239 void af_alg_wmem_wakeup(struct sock *sk);
240 int af_alg_wait_for_data(struct sock *sk, unsigned flags);
241 void af_alg_data_wakeup(struct sock *sk);
242 int af_alg_sendmsg(struct socket *sock, struct msghdr *msg, size_t size,
243 unsigned int ivsize);
244 ssize_t af_alg_sendpage(struct socket *sock, struct page *page,
245 int offset, size_t size, int flags);
246 void af_alg_free_resources(struct af_alg_async_req *areq);
247 void af_alg_async_cb(struct crypto_async_request *_req, int err);
248 __poll_t af_alg_poll(struct file *file, struct socket *sock,
249 poll_table *wait);
250 struct af_alg_async_req *af_alg_alloc_areq(struct sock *sk,
251 unsigned int areqlen);
252 int af_alg_get_rsgl(struct sock *sk, struct msghdr *msg, int flags,
253 struct af_alg_async_req *areq, size_t maxsize,
254 size_t *outlen);
255
256 #endif /* _CRYPTO_IF_ALG_H */
257
