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