| // SPDX-License-Identifier: GPL-2.0-or-later | 
 | /* | 
 |  * algif_skcipher: User-space interface for skcipher algorithms | 
 |  * | 
 |  * This file provides the user-space API for symmetric key ciphers. | 
 |  * | 
 |  * Copyright (c) 2010 Herbert Xu <herbert@gondor.apana.org.au> | 
 |  * | 
 |  * The following concept of the memory management is used: | 
 |  * | 
 |  * The kernel maintains two SGLs, the TX SGL and the RX SGL. The TX SGL is | 
 |  * filled by user space with the data submitted via sendpage/sendmsg. Filling | 
 |  * up the TX SGL does not cause a crypto operation -- the data will only be | 
 |  * tracked by the kernel. Upon receipt of one recvmsg call, the caller must | 
 |  * provide a buffer which is tracked with the RX SGL. | 
 |  * | 
 |  * During the processing of the recvmsg operation, the cipher request is | 
 |  * allocated and prepared. As part of the recvmsg operation, the processed | 
 |  * TX buffers are extracted from the TX SGL into a separate SGL. | 
 |  * | 
 |  * After the completion of the crypto operation, the RX SGL and the cipher | 
 |  * request is released. The extracted TX SGL parts are released together with | 
 |  * the RX SGL release. | 
 |  */ | 
 |  | 
 | #include <crypto/scatterwalk.h> | 
 | #include <crypto/skcipher.h> | 
 | #include <crypto/if_alg.h> | 
 | #include <linux/init.h> | 
 | #include <linux/list.h> | 
 | #include <linux/kernel.h> | 
 | #include <linux/mm.h> | 
 | #include <linux/module.h> | 
 | #include <linux/net.h> | 
 | #include <net/sock.h> | 
 |  | 
 | static int skcipher_sendmsg(struct socket *sock, struct msghdr *msg, | 
 | 			    size_t size) | 
 | { | 
 | 	struct sock *sk = sock->sk; | 
 | 	struct alg_sock *ask = alg_sk(sk); | 
 | 	struct sock *psk = ask->parent; | 
 | 	struct alg_sock *pask = alg_sk(psk); | 
 | 	struct crypto_skcipher *tfm = pask->private; | 
 | 	unsigned ivsize = crypto_skcipher_ivsize(tfm); | 
 |  | 
 | 	return af_alg_sendmsg(sock, msg, size, ivsize); | 
 | } | 
 |  | 
 | static int _skcipher_recvmsg(struct socket *sock, struct msghdr *msg, | 
 | 			     size_t ignored, int flags) | 
 | { | 
 | 	struct sock *sk = sock->sk; | 
 | 	struct alg_sock *ask = alg_sk(sk); | 
 | 	struct sock *psk = ask->parent; | 
 | 	struct alg_sock *pask = alg_sk(psk); | 
 | 	struct af_alg_ctx *ctx = ask->private; | 
 | 	struct crypto_skcipher *tfm = pask->private; | 
 | 	unsigned int bs = crypto_skcipher_chunksize(tfm); | 
 | 	struct af_alg_async_req *areq; | 
 | 	int err = 0; | 
 | 	size_t len = 0; | 
 |  | 
 | 	if (!ctx->init || (ctx->more && ctx->used < bs)) { | 
 | 		err = af_alg_wait_for_data(sk, flags, bs); | 
 | 		if (err) | 
 | 			return err; | 
 | 	} | 
 |  | 
 | 	/* Allocate cipher request for current operation. */ | 
 | 	areq = af_alg_alloc_areq(sk, sizeof(struct af_alg_async_req) + | 
 | 				     crypto_skcipher_reqsize(tfm)); | 
 | 	if (IS_ERR(areq)) | 
 | 		return PTR_ERR(areq); | 
 |  | 
 | 	/* convert iovecs of output buffers into RX SGL */ | 
 | 	err = af_alg_get_rsgl(sk, msg, flags, areq, ctx->used, &len); | 
 | 	if (err) | 
 | 		goto free; | 
 |  | 
 | 	/* | 
 | 	 * If more buffers are to be expected to be processed, process only | 
 | 	 * full block size buffers. | 
 | 	 */ | 
 | 	if (ctx->more || len < ctx->used) | 
 | 		len -= len % bs; | 
 |  | 
 | 	/* | 
 | 	 * Create a per request TX SGL for this request which tracks the | 
 | 	 * SG entries from the global TX SGL. | 
 | 	 */ | 
 | 	areq->tsgl_entries = af_alg_count_tsgl(sk, len, 0); | 
 | 	if (!areq->tsgl_entries) | 
 | 		areq->tsgl_entries = 1; | 
 | 	areq->tsgl = sock_kmalloc(sk, array_size(sizeof(*areq->tsgl), | 
 | 						 areq->tsgl_entries), | 
 | 				  GFP_KERNEL); | 
 | 	if (!areq->tsgl) { | 
 | 		err = -ENOMEM; | 
 | 		goto free; | 
 | 	} | 
 | 	sg_init_table(areq->tsgl, areq->tsgl_entries); | 
 | 	af_alg_pull_tsgl(sk, len, areq->tsgl, 0); | 
 |  | 
 | 	/* Initialize the crypto operation */ | 
 | 	skcipher_request_set_tfm(&areq->cra_u.skcipher_req, tfm); | 
 | 	skcipher_request_set_crypt(&areq->cra_u.skcipher_req, areq->tsgl, | 
 | 				   areq->first_rsgl.sgl.sg, len, ctx->iv); | 
 |  | 
 | 	if (msg->msg_iocb && !is_sync_kiocb(msg->msg_iocb)) { | 
 | 		/* AIO operation */ | 
 | 		sock_hold(sk); | 
 | 		areq->iocb = msg->msg_iocb; | 
 |  | 
 | 		/* Remember output size that will be generated. */ | 
 | 		areq->outlen = len; | 
 |  | 
 | 		skcipher_request_set_callback(&areq->cra_u.skcipher_req, | 
 | 					      CRYPTO_TFM_REQ_MAY_SLEEP, | 
 | 					      af_alg_async_cb, areq); | 
 | 		err = ctx->enc ? | 
 | 			crypto_skcipher_encrypt(&areq->cra_u.skcipher_req) : | 
 | 			crypto_skcipher_decrypt(&areq->cra_u.skcipher_req); | 
 |  | 
 | 		/* AIO operation in progress */ | 
 | 		if (err == -EINPROGRESS) | 
 | 			return -EIOCBQUEUED; | 
 |  | 
 | 		sock_put(sk); | 
 | 	} else { | 
 | 		/* Synchronous operation */ | 
 | 		skcipher_request_set_callback(&areq->cra_u.skcipher_req, | 
 | 					      CRYPTO_TFM_REQ_MAY_SLEEP | | 
 | 					      CRYPTO_TFM_REQ_MAY_BACKLOG, | 
 | 					      crypto_req_done, &ctx->wait); | 
 | 		err = crypto_wait_req(ctx->enc ? | 
 | 			crypto_skcipher_encrypt(&areq->cra_u.skcipher_req) : | 
 | 			crypto_skcipher_decrypt(&areq->cra_u.skcipher_req), | 
 | 						 &ctx->wait); | 
 | 	} | 
 |  | 
 |  | 
 | free: | 
 | 	af_alg_free_resources(areq); | 
 |  | 
 | 	return err ? err : len; | 
 | } | 
 |  | 
 | static int skcipher_recvmsg(struct socket *sock, struct msghdr *msg, | 
 | 			    size_t ignored, int flags) | 
 | { | 
 | 	struct sock *sk = sock->sk; | 
 | 	int ret = 0; | 
 |  | 
 | 	lock_sock(sk); | 
 | 	while (msg_data_left(msg)) { | 
 | 		int err = _skcipher_recvmsg(sock, msg, ignored, flags); | 
 |  | 
 | 		/* | 
 | 		 * This error covers -EIOCBQUEUED which implies that we can | 
 | 		 * only handle one AIO request. If the caller wants to have | 
 | 		 * multiple AIO requests in parallel, he must make multiple | 
 | 		 * separate AIO calls. | 
 | 		 * | 
 | 		 * Also return the error if no data has been processed so far. | 
 | 		 */ | 
 | 		if (err <= 0) { | 
 | 			if (err == -EIOCBQUEUED || !ret) | 
 | 				ret = err; | 
 | 			goto out; | 
 | 		} | 
 |  | 
 | 		ret += err; | 
 | 	} | 
 |  | 
 | out: | 
 | 	af_alg_wmem_wakeup(sk); | 
 | 	release_sock(sk); | 
 | 	return ret; | 
 | } | 
 |  | 
 | static struct proto_ops algif_skcipher_ops = { | 
 | 	.family		=	PF_ALG, | 
 |  | 
 | 	.connect	=	sock_no_connect, | 
 | 	.socketpair	=	sock_no_socketpair, | 
 | 	.getname	=	sock_no_getname, | 
 | 	.ioctl		=	sock_no_ioctl, | 
 | 	.listen		=	sock_no_listen, | 
 | 	.shutdown	=	sock_no_shutdown, | 
 | 	.mmap		=	sock_no_mmap, | 
 | 	.bind		=	sock_no_bind, | 
 | 	.accept		=	sock_no_accept, | 
 |  | 
 | 	.release	=	af_alg_release, | 
 | 	.sendmsg	=	skcipher_sendmsg, | 
 | 	.sendpage	=	af_alg_sendpage, | 
 | 	.recvmsg	=	skcipher_recvmsg, | 
 | 	.poll		=	af_alg_poll, | 
 | }; | 
 |  | 
 | static int skcipher_check_key(struct socket *sock) | 
 | { | 
 | 	int err = 0; | 
 | 	struct sock *psk; | 
 | 	struct alg_sock *pask; | 
 | 	struct crypto_skcipher *tfm; | 
 | 	struct sock *sk = sock->sk; | 
 | 	struct alg_sock *ask = alg_sk(sk); | 
 |  | 
 | 	lock_sock(sk); | 
 | 	if (!atomic_read(&ask->nokey_refcnt)) | 
 | 		goto unlock_child; | 
 |  | 
 | 	psk = ask->parent; | 
 | 	pask = alg_sk(ask->parent); | 
 | 	tfm = pask->private; | 
 |  | 
 | 	err = -ENOKEY; | 
 | 	lock_sock_nested(psk, SINGLE_DEPTH_NESTING); | 
 | 	if (crypto_skcipher_get_flags(tfm) & CRYPTO_TFM_NEED_KEY) | 
 | 		goto unlock; | 
 |  | 
 | 	atomic_dec(&pask->nokey_refcnt); | 
 | 	atomic_set(&ask->nokey_refcnt, 0); | 
 |  | 
 | 	err = 0; | 
 |  | 
 | unlock: | 
 | 	release_sock(psk); | 
 | unlock_child: | 
 | 	release_sock(sk); | 
 |  | 
 | 	return err; | 
 | } | 
 |  | 
 | static int skcipher_sendmsg_nokey(struct socket *sock, struct msghdr *msg, | 
 | 				  size_t size) | 
 | { | 
 | 	int err; | 
 |  | 
 | 	err = skcipher_check_key(sock); | 
 | 	if (err) | 
 | 		return err; | 
 |  | 
 | 	return skcipher_sendmsg(sock, msg, size); | 
 | } | 
 |  | 
 | static ssize_t skcipher_sendpage_nokey(struct socket *sock, struct page *page, | 
 | 				       int offset, size_t size, int flags) | 
 | { | 
 | 	int err; | 
 |  | 
 | 	err = skcipher_check_key(sock); | 
 | 	if (err) | 
 | 		return err; | 
 |  | 
 | 	return af_alg_sendpage(sock, page, offset, size, flags); | 
 | } | 
 |  | 
 | static int skcipher_recvmsg_nokey(struct socket *sock, struct msghdr *msg, | 
 | 				  size_t ignored, int flags) | 
 | { | 
 | 	int err; | 
 |  | 
 | 	err = skcipher_check_key(sock); | 
 | 	if (err) | 
 | 		return err; | 
 |  | 
 | 	return skcipher_recvmsg(sock, msg, ignored, flags); | 
 | } | 
 |  | 
 | static struct proto_ops algif_skcipher_ops_nokey = { | 
 | 	.family		=	PF_ALG, | 
 |  | 
 | 	.connect	=	sock_no_connect, | 
 | 	.socketpair	=	sock_no_socketpair, | 
 | 	.getname	=	sock_no_getname, | 
 | 	.ioctl		=	sock_no_ioctl, | 
 | 	.listen		=	sock_no_listen, | 
 | 	.shutdown	=	sock_no_shutdown, | 
 | 	.mmap		=	sock_no_mmap, | 
 | 	.bind		=	sock_no_bind, | 
 | 	.accept		=	sock_no_accept, | 
 |  | 
 | 	.release	=	af_alg_release, | 
 | 	.sendmsg	=	skcipher_sendmsg_nokey, | 
 | 	.sendpage	=	skcipher_sendpage_nokey, | 
 | 	.recvmsg	=	skcipher_recvmsg_nokey, | 
 | 	.poll		=	af_alg_poll, | 
 | }; | 
 |  | 
 | static void *skcipher_bind(const char *name, u32 type, u32 mask) | 
 | { | 
 | 	return crypto_alloc_skcipher(name, type, mask); | 
 | } | 
 |  | 
 | static void skcipher_release(void *private) | 
 | { | 
 | 	crypto_free_skcipher(private); | 
 | } | 
 |  | 
 | static int skcipher_setkey(void *private, const u8 *key, unsigned int keylen) | 
 | { | 
 | 	return crypto_skcipher_setkey(private, key, keylen); | 
 | } | 
 |  | 
 | static void skcipher_sock_destruct(struct sock *sk) | 
 | { | 
 | 	struct alg_sock *ask = alg_sk(sk); | 
 | 	struct af_alg_ctx *ctx = ask->private; | 
 | 	struct sock *psk = ask->parent; | 
 | 	struct alg_sock *pask = alg_sk(psk); | 
 | 	struct crypto_skcipher *tfm = pask->private; | 
 |  | 
 | 	af_alg_pull_tsgl(sk, ctx->used, NULL, 0); | 
 | 	sock_kzfree_s(sk, ctx->iv, crypto_skcipher_ivsize(tfm)); | 
 | 	sock_kfree_s(sk, ctx, ctx->len); | 
 | 	af_alg_release_parent(sk); | 
 | } | 
 |  | 
 | static int skcipher_accept_parent_nokey(void *private, struct sock *sk) | 
 | { | 
 | 	struct af_alg_ctx *ctx; | 
 | 	struct alg_sock *ask = alg_sk(sk); | 
 | 	struct crypto_skcipher *tfm = private; | 
 | 	unsigned int len = sizeof(*ctx); | 
 |  | 
 | 	ctx = sock_kmalloc(sk, len, GFP_KERNEL); | 
 | 	if (!ctx) | 
 | 		return -ENOMEM; | 
 | 	memset(ctx, 0, len); | 
 |  | 
 | 	ctx->iv = sock_kmalloc(sk, crypto_skcipher_ivsize(tfm), | 
 | 			       GFP_KERNEL); | 
 | 	if (!ctx->iv) { | 
 | 		sock_kfree_s(sk, ctx, len); | 
 | 		return -ENOMEM; | 
 | 	} | 
 | 	memset(ctx->iv, 0, crypto_skcipher_ivsize(tfm)); | 
 |  | 
 | 	INIT_LIST_HEAD(&ctx->tsgl_list); | 
 | 	ctx->len = len; | 
 | 	crypto_init_wait(&ctx->wait); | 
 |  | 
 | 	ask->private = ctx; | 
 |  | 
 | 	sk->sk_destruct = skcipher_sock_destruct; | 
 |  | 
 | 	return 0; | 
 | } | 
 |  | 
 | static int skcipher_accept_parent(void *private, struct sock *sk) | 
 | { | 
 | 	struct crypto_skcipher *tfm = private; | 
 |  | 
 | 	if (crypto_skcipher_get_flags(tfm) & CRYPTO_TFM_NEED_KEY) | 
 | 		return -ENOKEY; | 
 |  | 
 | 	return skcipher_accept_parent_nokey(private, sk); | 
 | } | 
 |  | 
 | static const struct af_alg_type algif_type_skcipher = { | 
 | 	.bind		=	skcipher_bind, | 
 | 	.release	=	skcipher_release, | 
 | 	.setkey		=	skcipher_setkey, | 
 | 	.accept		=	skcipher_accept_parent, | 
 | 	.accept_nokey	=	skcipher_accept_parent_nokey, | 
 | 	.ops		=	&algif_skcipher_ops, | 
 | 	.ops_nokey	=	&algif_skcipher_ops_nokey, | 
 | 	.name		=	"skcipher", | 
 | 	.owner		=	THIS_MODULE | 
 | }; | 
 |  | 
 | static int __init algif_skcipher_init(void) | 
 | { | 
 | 	return af_alg_register_type(&algif_type_skcipher); | 
 | } | 
 |  | 
 | static void __exit algif_skcipher_exit(void) | 
 | { | 
 | 	int err = af_alg_unregister_type(&algif_type_skcipher); | 
 | 	BUG_ON(err); | 
 | } | 
 |  | 
 | module_init(algif_skcipher_init); | 
 | module_exit(algif_skcipher_exit); | 
 | MODULE_LICENSE("GPL"); |