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
24struct crypto_async_request;
25
26struct 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
39struct af_alg_control {
40	struct af_alg_iv *iv;
41	int op;
42	unsigned int aead_assoclen;
43};
44
45struct 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
60struct 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 */
67struct 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 */
77struct 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 */
96struct 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 * @inflight:		Non-zero when AIO requests are in flight.
142 */
143struct af_alg_ctx {
144	struct list_head tsgl_list;
145
146	void *iv;
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
164int af_alg_register_type(const struct af_alg_type *type);
165int af_alg_unregister_type(const struct af_alg_type *type);
166
167int af_alg_release(struct socket *sock);
168void af_alg_release_parent(struct sock *sk);
169int af_alg_accept(struct sock *sk, struct socket *newsock, bool kern);
170
171int af_alg_make_sg(struct af_alg_sgl *sgl, struct iov_iter *iter, int len);
172void af_alg_free_sg(struct af_alg_sgl *sgl);
173
174static 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 */
185static 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 */
200static 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 */
211static 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 */
226static inline bool af_alg_readable(struct sock *sk)
227{
228	return PAGE_SIZE <= af_alg_rcvbuf(sk);
229}
230
231unsigned int af_alg_count_tsgl(struct sock *sk, size_t bytes, size_t offset);
232void af_alg_pull_tsgl(struct sock *sk, size_t used, struct scatterlist *dst,
233		      size_t dst_offset);
234void af_alg_wmem_wakeup(struct sock *sk);
235int af_alg_wait_for_data(struct sock *sk, unsigned flags, unsigned min);
236int af_alg_sendmsg(struct socket *sock, struct msghdr *msg, size_t size,
237		   unsigned int ivsize);
238ssize_t af_alg_sendpage(struct socket *sock, struct page *page,
239			int offset, size_t size, int flags);
240void af_alg_free_resources(struct af_alg_async_req *areq);
241void af_alg_async_cb(struct crypto_async_request *_req, int err);
242__poll_t af_alg_poll(struct file *file, struct socket *sock,
243			 poll_table *wait);
244struct af_alg_async_req *af_alg_alloc_areq(struct sock *sk,
245					   unsigned int areqlen);
246int af_alg_get_rsgl(struct sock *sk, struct msghdr *msg, int flags,
247		    struct af_alg_async_req *areq, size_t maxsize,
248		    size_t *outlen);
249
250#endif	/* _CRYPTO_IF_ALG_H */
251