| // 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 || err == -EBUSY) |
| 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"); |