[v6,3/6] crypto: AF_ALG -- add asymmetric cipher interface

Message ID	20160515041701.15888.53830.stgit@tstruk-mobl1 (mailing list archive)
State	RFC
Delegated to:	Herbert Xu
Headers	show Return-Path: <linux-crypto-owner@kernel.org> Subject: [PATCH v6 3/6] crypto: AF_ALG -- add asymmetric cipher interface From: Tadeusz Struk <tadeusz.struk@intel.com> To: dhowells@redhat.com Cc: herbert@gondor.apana.org.au, tadeusz.struk@intel.com, smueller@chronox.de, linux-api@vger.kernel.org, marcel@holtmann.org, linux-kernel@vger.kernel.org, keyrings@vger.kernel.org, linux-crypto@vger.kernel.org, dwmw2@infradead.org, davem@davemloft.net Date: Sat, 14 May 2016 21:17:01 -0700 Message-ID: <20160515041701.15888.53830.stgit@tstruk-mobl1> In-Reply-To: <20160515041645.15888.94903.stgit@tstruk-mobl1> References: <20160515041645.15888.94903.stgit@tstruk-mobl1> User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-crypto-owner@vger.kernel.org Precedence: bulk

diff --git a/crypto/algif_akcipher.c b/crypto/algif_akcipher.c new file mode 100644 index 0000000..6342b6e --- /dev/null +++ b/crypto/algif_akcipher.c @@ -0,0 +1,542 @@ +/* + * algif_akcipher: User-space interface for asymmetric cipher algorithms + * + * Copyright (C) 2015, Stephan Mueller <smueller@chronox.de> + * + * This file provides the user-space API for asymmetric ciphers. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License as published by the Free + * Software Foundation; either version 2 of the License, or (at your option) + * any later version. + */ + +#include <crypto/akcipher.h> +#include <crypto/scatterwalk.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> + +struct akcipher_sg_list { + unsigned int cur; + struct scatterlist sg[ALG_MAX_PAGES]; +}; + +struct akcipher_ctx { + struct akcipher_sg_list tsgl; + struct af_alg_sgl rsgl[ALG_MAX_PAGES]; + + struct af_alg_completion completion; + + unsigned long used; + + unsigned int len; + bool more; + bool merge; + int op; + + struct akcipher_request req; +}; + +static inline int akcipher_sndbuf(struct sock *sk) +{ + struct alg_sock *ask = alg_sk(sk); + struct akcipher_ctx *ctx = ask->private; + + return max_t(int, max_t(int, sk->sk_sndbuf & PAGE_MASK, PAGE_SIZE) - + ctx->used, 0); +} + +static inline bool akcipher_writable(struct sock *sk) +{ + return akcipher_sndbuf(sk) >= PAGE_SIZE; +} + +static inline int akcipher_calcsize(struct akcipher_ctx *ctx) +{ + return crypto_akcipher_maxsize(crypto_akcipher_reqtfm(&ctx->req)); +} + +static void akcipher_put_sgl(struct sock *sk) +{ + struct alg_sock *ask = alg_sk(sk); + struct akcipher_ctx *ctx = ask->private; + struct akcipher_sg_list *sgl = &ctx->tsgl; + struct scatterlist *sg = sgl->sg; + unsigned int i; + + for (i = 0; i < sgl->cur; i++) { + if (!sg_page(sg + i)) + continue; + + put_page(sg_page(sg + i)); + sg_assign_page(sg + i, NULL); + } + sg_init_table(sg, ALG_MAX_PAGES); + sgl->cur = 0; + ctx->used = 0; + ctx->more = 0; + ctx->merge = 0; +} + +static void akcipher_wmem_wakeup(struct sock *sk) +{ + struct socket_wq *wq; + + if (!akcipher_writable(sk)) + return; + + rcu_read_lock(); + wq = rcu_dereference(sk->sk_wq); + if (wq_has_sleeper(&wq->wait)) + wake_up_interruptible_sync_poll(&wq->wait, POLLIN | + POLLRDNORM | + POLLRDBAND); + sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_IN); + rcu_read_unlock(); +} + +static int akcipher_wait_for_data(struct sock *sk, unsigned int flags) +{ + struct alg_sock *ask = alg_sk(sk); + struct akcipher_ctx *ctx = ask->private; + long timeout; + DEFINE_WAIT(wait); + int err = -ERESTARTSYS; + + if (flags & MSG_DONTWAIT) + return -EAGAIN; + + set_bit(SOCKWQ_ASYNC_WAITDATA, &sk->sk_socket->flags); + + for (;;) { + if (signal_pending(current)) + break; + prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE); + timeout = MAX_SCHEDULE_TIMEOUT; + if (sk_wait_event(sk, &timeout, !ctx->more)) { + err = 0; + break; + } + } + finish_wait(sk_sleep(sk), &wait); + + clear_bit(SOCKWQ_ASYNC_WAITDATA, &sk->sk_socket->flags); + + return err; +} + +static void akcipher_data_wakeup(struct sock *sk) +{ + struct alg_sock *ask = alg_sk(sk); + struct akcipher_ctx *ctx = ask->private; + struct socket_wq *wq; + + if (ctx->more) + return; + if (!ctx->used) + return; + + rcu_read_lock(); + wq = rcu_dereference(sk->sk_wq); + if (wq_has_sleeper(&wq->wait)) + wake_up_interruptible_sync_poll(&wq->wait, POLLOUT | + POLLRDNORM | + POLLRDBAND); + sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT); + rcu_read_unlock(); +} + +static int akcipher_sendmsg(struct socket *sock, struct msghdr *msg, + size_t size) +{ + struct sock *sk = sock->sk; + struct alg_sock *ask = alg_sk(sk); + struct akcipher_ctx *ctx = ask->private; + struct akcipher_sg_list *sgl = &ctx->tsgl; + struct af_alg_control con = {}; + long copied = 0; + int op = 0; + bool init = 0; + int err; + + if (msg->msg_controllen) { + err = af_alg_cmsg_send(msg, &con); + if (err) + return err; + + init = 1; + switch (con.op) { + case ALG_OP_VERIFY: + case ALG_OP_SIGN: + case ALG_OP_ENCRYPT: + case ALG_OP_DECRYPT: + op = con.op; + break; + default: + return -EINVAL; + } + } + + lock_sock(sk); + if (!ctx->more && ctx->used) + goto unlock; + + if (init) + ctx->op = op; + + while (size) { + unsigned long len = size; + struct scatterlist *sg = NULL; + + /* use the existing memory in an allocated page */ + if (ctx->merge) { + sg = sgl->sg + sgl->cur - 1; + len = min_t(unsigned long, len, + PAGE_SIZE - sg->offset - sg->length); + err = memcpy_from_msg(page_address(sg_page(sg)) + + sg->offset + sg->length, + msg, len); + if (err) + goto unlock; + + sg->length += len; + ctx->merge = (sg->offset + sg->length) & + (PAGE_SIZE - 1); + + ctx->used += len; + copied += len; + size -= len; + continue; + } + + if (!akcipher_writable(sk)) { + /* user space sent too much data */ + akcipher_put_sgl(sk); + err = -EMSGSIZE; + goto unlock; + } + + /* allocate a new page */ + len = min_t(unsigned long, size, akcipher_sndbuf(sk)); + while (len) { + int plen = 0; + + if (sgl->cur >= ALG_MAX_PAGES) { + akcipher_put_sgl(sk); + err = -E2BIG; + goto unlock; + } + + sg = sgl->sg + sgl->cur; + plen = min_t(int, len, PAGE_SIZE); + + sg_assign_page(sg, alloc_page(GFP_KERNEL)); + if (!sg_page(sg)) { + err = -ENOMEM; + goto unlock; + } + + err = memcpy_from_msg(page_address(sg_page(sg)), + msg, plen); + if (err) { + __free_page(sg_page(sg)); + sg_assign_page(sg, NULL); + goto unlock; + } + + sg->offset = 0; + sg->length = plen; + len -= plen; + ctx->used += plen; + copied += plen; + sgl->cur++; + size -= plen; + ctx->merge = plen & (PAGE_SIZE - 1); + } + } + + err = 0; + + ctx->more = msg->msg_flags & MSG_MORE; + +unlock: + akcipher_data_wakeup(sk); + release_sock(sk); + + return err ?: copied; +} + +static ssize_t akcipher_sendpage(struct socket *sock, struct page *page, + int offset, size_t size, int flags) +{ + struct sock *sk = sock->sk; + struct alg_sock *ask = alg_sk(sk); + struct akcipher_ctx *ctx = ask->private; + struct akcipher_sg_list *sgl = &ctx->tsgl; + int err = 0; + + if (flags & MSG_SENDPAGE_NOTLAST) + flags |= MSG_MORE; + + if (sgl->cur >= ALG_MAX_PAGES) + return -E2BIG; + + lock_sock(sk); + if (!ctx->more && ctx->used) + goto unlock; + + if (!size) + goto done; + + if (!akcipher_writable(sk)) { + /* user space sent too much data */ + akcipher_put_sgl(sk); + err = -EMSGSIZE; + goto unlock; + } + + ctx->merge = 0; + + get_page(page); + sg_set_page(sgl->sg + sgl->cur, page, size, offset); + sgl->cur++; + ctx->used += size; + +done: + ctx->more = flags & MSG_MORE; +unlock: + akcipher_data_wakeup(sk); + release_sock(sk); + + return err ? err : size; +} + +static int akcipher_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 akcipher_ctx *ctx = ask->private; + struct akcipher_sg_list *sgl = &ctx->tsgl; + unsigned int i = 0; + int err; + unsigned long used = 0; + size_t usedpages = 0; + unsigned int cnt = 0; + + /* Limit number of IOV blocks to be accessed below */ + if (msg->msg_iter.nr_segs > ALG_MAX_PAGES) + return -ENOMSG; + + lock_sock(sk); + + if (ctx->more) { + err = akcipher_wait_for_data(sk, flags); + if (err) + goto unlock; + } + + used = ctx->used; + + /* convert iovecs of output buffers into scatterlists */ + while (iov_iter_count(&msg->msg_iter)) { + /* make one iovec available as scatterlist */ + err = af_alg_make_sg(&ctx->rsgl[cnt], &msg->msg_iter, + iov_iter_count(&msg->msg_iter)); + if (err < 0) + goto unlock; + usedpages += err; + /* chain the new scatterlist with previous one */ + if (cnt) + af_alg_link_sg(&ctx->rsgl[cnt - 1], &ctx->rsgl[cnt]); + + iov_iter_advance(&msg->msg_iter, err); + cnt++; + } + + /* ensure output buffer is sufficiently large */ + if (usedpages < akcipher_calcsize(ctx)) { + err = -EMSGSIZE; + goto unlock; + } + + sg_mark_end(sgl->sg + sgl->cur - 1); + + akcipher_request_set_crypt(&ctx->req, sgl->sg, ctx->rsgl[0].sg, used, + usedpages); + switch (ctx->op) { + case ALG_OP_VERIFY: + err = crypto_akcipher_verify(&ctx->req); + break; + case ALG_OP_SIGN: + err = crypto_akcipher_sign(&ctx->req); + break; + case ALG_OP_ENCRYPT: + err = crypto_akcipher_encrypt(&ctx->req); + break; + case ALG_OP_DECRYPT: + err = crypto_akcipher_decrypt(&ctx->req); + break; + default: + err = -EFAULT; + goto unlock; + } + + err = af_alg_wait_for_completion(err, &ctx->completion); + + if (err) { + /* EBADMSG implies a valid cipher operation took place */ + if (err == -EBADMSG) + akcipher_put_sgl(sk); + goto unlock; + } + + akcipher_put_sgl(sk); + +unlock: + for (i = 0; i < cnt; i++) + af_alg_free_sg(&ctx->rsgl[i]); + + akcipher_wmem_wakeup(sk); + release_sock(sk); + + return err ? err : ctx->req.dst_len; +} + +static unsigned int akcipher_poll(struct file *file, struct socket *sock, + poll_table *wait) +{ + struct sock *sk = sock->sk; + struct alg_sock *ask = alg_sk(sk); + struct akcipher_ctx *ctx = ask->private; + unsigned int mask = 0; + + sock_poll_wait(file, sk_sleep(sk), wait); + + if (!ctx->more) + mask |= POLLIN | POLLRDNORM; + + if (akcipher_writable(sk)) + mask |= POLLOUT | POLLWRNORM | POLLWRBAND; + + return mask; +} + +static struct proto_ops algif_akcipher_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, + .getsockopt = sock_no_getsockopt, + .mmap = sock_no_mmap, + .bind = sock_no_bind, + .accept = sock_no_accept, + .setsockopt = sock_no_setsockopt, + + .release = af_alg_release, + .sendmsg = akcipher_sendmsg, + .sendpage = akcipher_sendpage, + .recvmsg = akcipher_recvmsg, + .poll = akcipher_poll, +}; + +static void *akcipher_bind(const char *name, u32 type, u32 mask) +{ + return crypto_alloc_akcipher(name, type, mask); +} + +static void akcipher_release(void *private) +{ + crypto_free_akcipher(private); +} + +static int akcipher_setprivkey(void *private, const u8 *key, + unsigned int keylen) +{ + return crypto_akcipher_set_priv_key(private, key, keylen); +} + +static int akcipher_setpubkey(void *private, const u8 *key, unsigned int keylen) +{ + return crypto_akcipher_set_pub_key(private, key, keylen); +} + +static void akcipher_sock_destruct(struct sock *sk) +{ + struct alg_sock *ask = alg_sk(sk); + struct akcipher_ctx *ctx = ask->private; + + akcipher_put_sgl(sk); + sock_kfree_s(sk, ctx, ctx->len); + af_alg_release_parent(sk); +} + +static int akcipher_accept_parent(void *private, struct sock *sk) +{ + struct akcipher_ctx *ctx; + struct alg_sock *ask = alg_sk(sk); + unsigned int len = sizeof(*ctx) + crypto_akcipher_reqsize(private); + + ctx = sock_kmalloc(sk, len, GFP_KERNEL); + if (!ctx) + return -ENOMEM; + memset(ctx, 0, len); + + ctx->len = len; + ctx->used = 0; + ctx->more = 0; + ctx->merge = 0; + ctx->op = 0; + ctx->tsgl.cur = 0; + af_alg_init_completion(&ctx->completion); + sg_init_table(ctx->tsgl.sg, ALG_MAX_PAGES); + + ask->private = ctx; + + akcipher_request_set_tfm(&ctx->req, private); + akcipher_request_set_callback(&ctx->req, CRYPTO_TFM_REQ_MAY_BACKLOG, + af_alg_complete, &ctx->completion); + + sk->sk_destruct = akcipher_sock_destruct; + + return 0; +} + +static const struct af_alg_type algif_type_akcipher = { + .bind = akcipher_bind, + .release = akcipher_release, + .setkey = akcipher_setprivkey, + .setpubkey = akcipher_setpubkey, + .accept = akcipher_accept_parent, + .ops = &algif_akcipher_ops, + .name = "akcipher", + .owner = THIS_MODULE +}; + +static int __init algif_akcipher_init(void) +{ + return af_alg_register_type(&algif_type_akcipher); +} + +static void __exit algif_akcipher_exit(void) +{ + int err = af_alg_unregister_type(&algif_type_akcipher); + + WARN_ON(err); +} + +module_init(algif_akcipher_init); +module_exit(algif_akcipher_exit); +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Stephan Mueller <smueller@chronox.de>"); +MODULE_DESCRIPTION("Asymmetric kernel crypto API user space interface");

[v6,3/6] crypto: AF_ALG -- add asymmetric cipher interface

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