if_alg.h

  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 alg_sock {
 25	/* struct sock must be the first member of struct alg_sock */
 26	struct sock sk;
 27
 28	struct sock *parent;
 29
 30	atomic_t refcnt;
 31	atomic_t nokey_refcnt;
 32
 33	const struct af_alg_type *type;
 34	void *private;
 35};
 36
 37struct af_alg_control {
 38	struct af_alg_iv *iv;
 39	int op;
 40	unsigned int aead_assoclen;
 41};
 42
 43struct af_alg_type {
 44	void *(*bind)(const char *name, u32 type, u32 mask);
 45	void (*release)(void *private);
 46	int (*setkey)(void *private, const u8 *key, unsigned int keylen);
 47	int (*setentropy)(void *private, sockptr_t entropy, unsigned int len);
 48	int (*accept)(void *private, struct sock *sk);
 49	int (*accept_nokey)(void *private, struct sock *sk);
 50	int (*setauthsize)(void *private, unsigned int authsize);
 51
 52	struct proto_ops *ops;
 53	struct proto_ops *ops_nokey;
 54	struct module *owner;
 55	char name[14];
 56};
 57
 58struct af_alg_sgl {
 59	struct sg_table sgt;
 60	struct scatterlist sgl[ALG_MAX_PAGES + 1];
 61	bool need_unpin;
 62};
 63
 64/* TX SGL entry */
 65struct af_alg_tsgl {
 66	struct list_head list;
 67	unsigned int cur;		/* Last processed SG entry */
 68	struct scatterlist sg[];	/* Array of SGs forming the SGL */
 69};
 70
 71#define MAX_SGL_ENTS ((4096 - sizeof(struct af_alg_tsgl)) / \
 72		      sizeof(struct scatterlist) - 1)
 73
 74/* RX SGL entry */
 75struct af_alg_rsgl {
 76	struct af_alg_sgl sgl;
 77	struct list_head list;
 78	size_t sg_num_bytes;		/* Bytes of data in that SGL */
 79};
 80
 81/**
 82 * struct af_alg_async_req - definition of crypto request
 83 * @iocb:		IOCB for AIO operations
 84 * @sk:			Socket the request is associated with
 85 * @first_rsgl:		First RX SG
 86 * @last_rsgl:		Pointer to last RX SG
 87 * @rsgl_list:		Track RX SGs
 88 * @tsgl:		Private, per request TX SGL of buffers to process
 89 * @tsgl_entries:	Number of entries in priv. TX SGL
 90 * @outlen:		Number of output bytes generated by crypto op
 91 * @areqlen:		Length of this data structure
 92 * @cra_u:		Cipher request
 93 */
 94struct af_alg_async_req {
 95	struct kiocb *iocb;
 96	struct sock *sk;
 97
 98	struct af_alg_rsgl first_rsgl;
 99	struct af_alg_rsgl *last_rsgl;
100	struct list_head rsgl_list;
101
102	struct scatterlist *tsgl;
103	unsigned int tsgl_entries;
104
105	unsigned int outlen;
106	unsigned int areqlen;
107
108	union {
109		struct aead_request aead_req;
110		struct skcipher_request skcipher_req;
111	} cra_u;
112
113	/* req ctx trails this struct */
114};
115
116/**
117 * struct af_alg_ctx - definition of the crypto context
118 *
119 * The crypto context tracks the input data during the lifetime of an AF_ALG
120 * socket.
121 *
122 * @tsgl_list:		Link to TX SGL
123 * @iv:			IV for cipher operation
124 * @state:		Existing state for continuing operation
125 * @aead_assoclen:	Length of AAD for AEAD cipher operations
126 * @completion:		Work queue for synchronous operation
127 * @used:		TX bytes sent to kernel. This variable is used to
128 *			ensure that user space cannot cause the kernel
129 *			to allocate too much memory in sendmsg operation.
130 * @rcvused:		Total RX bytes to be filled by kernel. This variable
131 *			is used to ensure user space cannot cause the kernel
132 *			to allocate too much memory in a recvmsg operation.
133 * @more:		More data to be expected from user space?
134 * @merge:		Shall new data from user space be merged into existing
135 *			SG?
136 * @enc:		Cryptographic operation to be performed when
137 *			recvmsg is invoked.
138 * @write:		True if we are in the middle of a write.
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	void *state;
148	size_t aead_assoclen;
149
150	struct crypto_wait wait;
151
152	size_t used;
153	atomic_t rcvused;
154
155	bool		more:1,
156			merge:1,
157			enc:1,
158			write:1,
159			init:1;
160
161	unsigned int len;
162
163	unsigned int inflight;
164};
165
166int af_alg_register_type(const struct af_alg_type *type);
167int af_alg_unregister_type(const struct af_alg_type *type);
168
169int af_alg_release(struct socket *sock);
170void af_alg_release_parent(struct sock *sk);
171int af_alg_accept(struct sock *sk, struct socket *newsock,
172		  struct proto_accept_arg *arg);
173
174void af_alg_free_sg(struct af_alg_sgl *sgl);
175
176static 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 */
187static 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 */
202static 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 */
213static 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 */
228static inline bool af_alg_readable(struct sock *sk)
229{
230	return PAGE_SIZE <= af_alg_rcvbuf(sk);
231}
232
233unsigned int af_alg_count_tsgl(struct sock *sk, size_t bytes);
234void af_alg_pull_tsgl(struct sock *sk, size_t used, struct scatterlist *dst);
235void af_alg_wmem_wakeup(struct sock *sk);
236int af_alg_wait_for_data(struct sock *sk, unsigned flags, unsigned min);
237int af_alg_sendmsg(struct socket *sock, struct msghdr *msg, size_t size,
238		   unsigned int ivsize);
239void af_alg_free_resources(struct af_alg_async_req *areq);
240void af_alg_async_cb(void *data, int err);
241__poll_t af_alg_poll(struct file *file, struct socket *sock,
242			 poll_table *wait);
243struct af_alg_async_req *af_alg_alloc_areq(struct sock *sk,
244					   unsigned int areqlen);
245int 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 */