402 lines
10 KiB
C
402 lines
10 KiB
C
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/*
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* algif_skcipher: User-space interface for skcipher algorithms
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*
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* This file provides the user-space API for symmetric key ciphers.
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*
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* Copyright (c) 2010 Herbert Xu <herbert@gondor.apana.org.au>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the Free
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* Software Foundation; either version 2 of the License, or (at your option)
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* any later version.
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*
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* The following concept of the memory management is used:
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*
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* The kernel maintains two SGLs, the TX SGL and the RX SGL. The TX SGL is
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* filled by user space with the data submitted via sendpage/sendmsg. Filling
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* up the TX SGL does not cause a crypto operation -- the data will only be
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* tracked by the kernel. Upon receipt of one recvmsg call, the caller must
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* provide a buffer which is tracked with the RX SGL.
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*
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* During the processing of the recvmsg operation, the cipher request is
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* allocated and prepared. As part of the recvmsg operation, the processed
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* TX buffers are extracted from the TX SGL into a separate SGL.
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*
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* After the completion of the crypto operation, the RX SGL and the cipher
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* request is released. The extracted TX SGL parts are released together with
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* the RX SGL release.
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*/
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#include <crypto/scatterwalk.h>
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#include <crypto/skcipher.h>
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#include <crypto/if_alg.h>
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#include <linux/init.h>
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#include <linux/list.h>
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#include <linux/kernel.h>
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#include <linux/mm.h>
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#include <linux/module.h>
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#include <linux/net.h>
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#include <net/sock.h>
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static int skcipher_sendmsg(struct socket *sock, struct msghdr *msg,
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size_t size)
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{
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struct sock *sk = sock->sk;
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struct alg_sock *ask = alg_sk(sk);
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struct sock *psk = ask->parent;
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struct alg_sock *pask = alg_sk(psk);
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struct crypto_skcipher *tfm = pask->private;
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unsigned ivsize = crypto_skcipher_ivsize(tfm);
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return af_alg_sendmsg(sock, msg, size, ivsize);
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}
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static int _skcipher_recvmsg(struct socket *sock, struct msghdr *msg,
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size_t ignored, int flags)
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{
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struct sock *sk = sock->sk;
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struct alg_sock *ask = alg_sk(sk);
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struct sock *psk = ask->parent;
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struct alg_sock *pask = alg_sk(psk);
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struct af_alg_ctx *ctx = ask->private;
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struct crypto_skcipher *tfm = pask->private;
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unsigned int bs = crypto_skcipher_blocksize(tfm);
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struct af_alg_async_req *areq;
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int err = 0;
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size_t len = 0;
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if (!ctx->used) {
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err = af_alg_wait_for_data(sk, flags);
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if (err)
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return err;
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}
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/* Allocate cipher request for current operation. */
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areq = af_alg_alloc_areq(sk, sizeof(struct af_alg_async_req) +
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crypto_skcipher_reqsize(tfm));
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if (IS_ERR(areq))
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return PTR_ERR(areq);
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/* convert iovecs of output buffers into RX SGL */
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err = af_alg_get_rsgl(sk, msg, flags, areq, ctx->used, &len);
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if (err)
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goto free;
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/*
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* If more buffers are to be expected to be processed, process only
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* full block size buffers.
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*/
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if (ctx->more || len < ctx->used)
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len -= len % bs;
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/*
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* Create a per request TX SGL for this request which tracks the
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* SG entries from the global TX SGL.
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*/
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areq->tsgl_entries = af_alg_count_tsgl(sk, len, 0);
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if (!areq->tsgl_entries)
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areq->tsgl_entries = 1;
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areq->tsgl = sock_kmalloc(sk, array_size(sizeof(*areq->tsgl),
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areq->tsgl_entries),
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GFP_KERNEL);
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if (!areq->tsgl) {
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err = -ENOMEM;
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goto free;
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}
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sg_init_table(areq->tsgl, areq->tsgl_entries);
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af_alg_pull_tsgl(sk, len, areq->tsgl, 0);
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/* Initialize the crypto operation */
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skcipher_request_set_tfm(&areq->cra_u.skcipher_req, tfm);
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skcipher_request_set_crypt(&areq->cra_u.skcipher_req, areq->tsgl,
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areq->first_rsgl.sgl.sg, len, ctx->iv);
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if (msg->msg_iocb && !is_sync_kiocb(msg->msg_iocb)) {
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/* AIO operation */
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sock_hold(sk);
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areq->iocb = msg->msg_iocb;
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/* Remember output size that will be generated. */
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areq->outlen = len;
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skcipher_request_set_callback(&areq->cra_u.skcipher_req,
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CRYPTO_TFM_REQ_MAY_SLEEP,
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af_alg_async_cb, areq);
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err = ctx->enc ?
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crypto_skcipher_encrypt(&areq->cra_u.skcipher_req) :
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crypto_skcipher_decrypt(&areq->cra_u.skcipher_req);
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/* AIO operation in progress */
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if (err == -EINPROGRESS)
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return -EIOCBQUEUED;
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sock_put(sk);
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} else {
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/* Synchronous operation */
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skcipher_request_set_callback(&areq->cra_u.skcipher_req,
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CRYPTO_TFM_REQ_MAY_SLEEP |
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CRYPTO_TFM_REQ_MAY_BACKLOG,
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crypto_req_done, &ctx->wait);
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err = crypto_wait_req(ctx->enc ?
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crypto_skcipher_encrypt(&areq->cra_u.skcipher_req) :
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crypto_skcipher_decrypt(&areq->cra_u.skcipher_req),
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&ctx->wait);
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}
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free:
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af_alg_free_resources(areq);
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return err ? err : len;
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}
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static int skcipher_recvmsg(struct socket *sock, struct msghdr *msg,
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size_t ignored, int flags)
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{
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struct sock *sk = sock->sk;
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int ret = 0;
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lock_sock(sk);
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while (msg_data_left(msg)) {
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int err = _skcipher_recvmsg(sock, msg, ignored, flags);
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/*
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* This error covers -EIOCBQUEUED which implies that we can
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* only handle one AIO request. If the caller wants to have
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* multiple AIO requests in parallel, he must make multiple
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* separate AIO calls.
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*
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* Also return the error if no data has been processed so far.
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*/
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if (err <= 0) {
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if (err == -EIOCBQUEUED || !ret)
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ret = err;
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goto out;
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}
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ret += err;
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}
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out:
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af_alg_wmem_wakeup(sk);
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release_sock(sk);
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return ret;
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}
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static struct proto_ops algif_skcipher_ops = {
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.family = PF_ALG,
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.connect = sock_no_connect,
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.socketpair = sock_no_socketpair,
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.getname = sock_no_getname,
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.ioctl = sock_no_ioctl,
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.listen = sock_no_listen,
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.shutdown = sock_no_shutdown,
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.getsockopt = sock_no_getsockopt,
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.mmap = sock_no_mmap,
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.bind = sock_no_bind,
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.accept = sock_no_accept,
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.setsockopt = sock_no_setsockopt,
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.release = af_alg_release,
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.sendmsg = skcipher_sendmsg,
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.sendpage = af_alg_sendpage,
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.recvmsg = skcipher_recvmsg,
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.poll = af_alg_poll,
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};
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static int skcipher_check_key(struct socket *sock)
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{
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int err = 0;
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struct sock *psk;
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struct alg_sock *pask;
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struct crypto_skcipher *tfm;
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struct sock *sk = sock->sk;
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struct alg_sock *ask = alg_sk(sk);
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lock_sock(sk);
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if (!atomic_read(&ask->nokey_refcnt))
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goto unlock_child;
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psk = ask->parent;
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pask = alg_sk(ask->parent);
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tfm = pask->private;
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err = -ENOKEY;
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lock_sock_nested(psk, SINGLE_DEPTH_NESTING);
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if (crypto_skcipher_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)
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goto unlock;
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atomic_dec(&pask->nokey_refcnt);
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atomic_set(&ask->nokey_refcnt, 0);
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err = 0;
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unlock:
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release_sock(psk);
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unlock_child:
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release_sock(sk);
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return err;
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}
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static int skcipher_sendmsg_nokey(struct socket *sock, struct msghdr *msg,
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size_t size)
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{
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int err;
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err = skcipher_check_key(sock);
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if (err)
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return err;
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return skcipher_sendmsg(sock, msg, size);
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}
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static ssize_t skcipher_sendpage_nokey(struct socket *sock, struct page *page,
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int offset, size_t size, int flags)
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{
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int err;
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err = skcipher_check_key(sock);
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if (err)
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return err;
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return af_alg_sendpage(sock, page, offset, size, flags);
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}
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static int skcipher_recvmsg_nokey(struct socket *sock, struct msghdr *msg,
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size_t ignored, int flags)
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{
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int err;
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err = skcipher_check_key(sock);
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if (err)
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return err;
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return skcipher_recvmsg(sock, msg, ignored, flags);
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}
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static struct proto_ops algif_skcipher_ops_nokey = {
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.family = PF_ALG,
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.connect = sock_no_connect,
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.socketpair = sock_no_socketpair,
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.getname = sock_no_getname,
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.ioctl = sock_no_ioctl,
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.listen = sock_no_listen,
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.shutdown = sock_no_shutdown,
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.getsockopt = sock_no_getsockopt,
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.mmap = sock_no_mmap,
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.bind = sock_no_bind,
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.accept = sock_no_accept,
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.setsockopt = sock_no_setsockopt,
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.release = af_alg_release,
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.sendmsg = skcipher_sendmsg_nokey,
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.sendpage = skcipher_sendpage_nokey,
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.recvmsg = skcipher_recvmsg_nokey,
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.poll = af_alg_poll,
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};
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static void *skcipher_bind(const char *name, u32 type, u32 mask)
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{
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return crypto_alloc_skcipher(name, type, mask);
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}
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static void skcipher_release(void *private)
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{
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crypto_free_skcipher(private);
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}
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static int skcipher_setkey(void *private, const u8 *key, unsigned int keylen)
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{
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return crypto_skcipher_setkey(private, key, keylen);
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}
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static void skcipher_sock_destruct(struct sock *sk)
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{
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struct alg_sock *ask = alg_sk(sk);
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struct af_alg_ctx *ctx = ask->private;
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struct sock *psk = ask->parent;
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struct alg_sock *pask = alg_sk(psk);
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struct crypto_skcipher *tfm = pask->private;
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af_alg_pull_tsgl(sk, ctx->used, NULL, 0);
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sock_kzfree_s(sk, ctx->iv, crypto_skcipher_ivsize(tfm));
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sock_kfree_s(sk, ctx, ctx->len);
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af_alg_release_parent(sk);
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}
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static int skcipher_accept_parent_nokey(void *private, struct sock *sk)
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{
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struct af_alg_ctx *ctx;
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struct alg_sock *ask = alg_sk(sk);
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struct crypto_skcipher *tfm = private;
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unsigned int len = sizeof(*ctx);
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ctx = sock_kmalloc(sk, len, GFP_KERNEL);
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if (!ctx)
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return -ENOMEM;
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ctx->iv = sock_kmalloc(sk, crypto_skcipher_ivsize(tfm),
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GFP_KERNEL);
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if (!ctx->iv) {
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sock_kfree_s(sk, ctx, len);
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return -ENOMEM;
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}
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memset(ctx->iv, 0, crypto_skcipher_ivsize(tfm));
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INIT_LIST_HEAD(&ctx->tsgl_list);
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ctx->len = len;
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ctx->used = 0;
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atomic_set(&ctx->rcvused, 0);
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ctx->more = 0;
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ctx->merge = 0;
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ctx->enc = 0;
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crypto_init_wait(&ctx->wait);
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ask->private = ctx;
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sk->sk_destruct = skcipher_sock_destruct;
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return 0;
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}
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static int skcipher_accept_parent(void *private, struct sock *sk)
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{
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struct crypto_skcipher *tfm = private;
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if (crypto_skcipher_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)
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return -ENOKEY;
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return skcipher_accept_parent_nokey(private, sk);
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}
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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");
|