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
alg_sk(struct sock * sk)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 */
af_alg_sndbuf(struct sock * sk)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 */
af_alg_writable(struct sock * sk)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 */
af_alg_rcvbuf(struct sock * sk)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 */
af_alg_readable(struct sock * sk)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 */
248
