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![Herbert Xu](/assets/img/avatar_default.png)
The async path cannot use MAY_BACKLOG because it is not meant to
block, which is what MAY_BACKLOG does. On the other hand, both
the sync and async paths can make use of MAY_SLEEP.
Fixes: 83094e5e9e
("crypto: af_alg - add async support to...")
Cc: <stable@vger.kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
605 lines
16 KiB
C
605 lines
16 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* algif_aead: User-space interface for AEAD algorithms
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*
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* Copyright (C) 2014, Stephan Mueller <smueller@chronox.de>
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*
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* This file provides the user-space API for AEAD ciphers.
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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/internal/aead.h>
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#include <crypto/scatterwalk.h>
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#include <crypto/if_alg.h>
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#include <crypto/skcipher.h>
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#include <crypto/null.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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struct aead_tfm {
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struct crypto_aead *aead;
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struct crypto_sync_skcipher *null_tfm;
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};
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static inline bool aead_sufficient_data(struct sock *sk)
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{
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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 aead_tfm *aeadc = pask->private;
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struct crypto_aead *tfm = aeadc->aead;
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unsigned int as = crypto_aead_authsize(tfm);
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/*
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* The minimum amount of memory needed for an AEAD cipher is
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* the AAD and in case of decryption the tag.
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*/
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return ctx->used >= ctx->aead_assoclen + (ctx->enc ? 0 : as);
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}
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static int aead_sendmsg(struct socket *sock, struct msghdr *msg, 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 aead_tfm *aeadc = pask->private;
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struct crypto_aead *tfm = aeadc->aead;
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unsigned int ivsize = crypto_aead_ivsize(tfm);
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return af_alg_sendmsg(sock, msg, size, ivsize);
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}
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static int crypto_aead_copy_sgl(struct crypto_sync_skcipher *null_tfm,
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struct scatterlist *src,
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struct scatterlist *dst, unsigned int len)
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{
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SYNC_SKCIPHER_REQUEST_ON_STACK(skreq, null_tfm);
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skcipher_request_set_sync_tfm(skreq, null_tfm);
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skcipher_request_set_callback(skreq, CRYPTO_TFM_REQ_MAY_SLEEP,
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NULL, NULL);
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skcipher_request_set_crypt(skreq, src, dst, len, NULL);
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return crypto_skcipher_encrypt(skreq);
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}
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static int _aead_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 aead_tfm *aeadc = pask->private;
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struct crypto_aead *tfm = aeadc->aead;
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struct crypto_sync_skcipher *null_tfm = aeadc->null_tfm;
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unsigned int i, as = crypto_aead_authsize(tfm);
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struct af_alg_async_req *areq;
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struct af_alg_tsgl *tsgl, *tmp;
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struct scatterlist *rsgl_src, *tsgl_src = NULL;
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int err = 0;
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size_t used = 0; /* [in] TX bufs to be en/decrypted */
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size_t outlen = 0; /* [out] RX bufs produced by kernel */
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size_t usedpages = 0; /* [in] RX bufs to be used from user */
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size_t processed = 0; /* [in] TX bufs to be consumed */
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if (!ctx->init || ctx->more) {
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err = af_alg_wait_for_data(sk, flags, 0);
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if (err)
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return err;
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}
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/*
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* Data length provided by caller via sendmsg/sendpage that has not
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* yet been processed.
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*/
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used = ctx->used;
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/*
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* Make sure sufficient data is present -- note, the same check is
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* also present in sendmsg/sendpage. The checks in sendpage/sendmsg
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* shall provide an information to the data sender that something is
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* wrong, but they are irrelevant to maintain the kernel integrity.
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* We need this check here too in case user space decides to not honor
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* the error message in sendmsg/sendpage and still call recvmsg. This
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* check here protects the kernel integrity.
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*/
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if (!aead_sufficient_data(sk))
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return -EINVAL;
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/*
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* Calculate the minimum output buffer size holding the result of the
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* cipher operation. When encrypting data, the receiving buffer is
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* larger by the tag length compared to the input buffer as the
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* encryption operation generates the tag. For decryption, the input
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* buffer provides the tag which is consumed resulting in only the
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* plaintext without a buffer for the tag returned to the caller.
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*/
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if (ctx->enc)
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outlen = used + as;
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else
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outlen = used - as;
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/*
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* The cipher operation input data is reduced by the associated data
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* length as this data is processed separately later on.
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*/
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used -= ctx->aead_assoclen;
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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_aead_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, outlen, &usedpages);
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if (err)
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goto free;
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/*
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* Ensure output buffer is sufficiently large. If the caller provides
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* less buffer space, only use the relative required input size. This
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* allows AIO operation where the caller sent all data to be processed
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* and the AIO operation performs the operation on the different chunks
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* of the input data.
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*/
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if (usedpages < outlen) {
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size_t less = outlen - usedpages;
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if (used < less) {
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err = -EINVAL;
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goto free;
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}
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used -= less;
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outlen -= less;
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}
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processed = used + ctx->aead_assoclen;
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list_for_each_entry_safe(tsgl, tmp, &ctx->tsgl_list, list) {
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for (i = 0; i < tsgl->cur; i++) {
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struct scatterlist *process_sg = tsgl->sg + i;
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if (!(process_sg->length) || !sg_page(process_sg))
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continue;
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tsgl_src = process_sg;
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break;
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}
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if (tsgl_src)
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break;
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}
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if (processed && !tsgl_src) {
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err = -EFAULT;
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goto free;
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}
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/*
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* Copy of AAD from source to destination
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*
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* The AAD is copied to the destination buffer without change. Even
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* when user space uses an in-place cipher operation, the kernel
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* will copy the data as it does not see whether such in-place operation
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* is initiated.
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*
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* To ensure efficiency, the following implementation ensure that the
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* ciphers are invoked to perform a crypto operation in-place. This
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* is achieved by memory management specified as follows.
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*/
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/* Use the RX SGL as source (and destination) for crypto op. */
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rsgl_src = areq->first_rsgl.sgl.sg;
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if (ctx->enc) {
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/*
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* Encryption operation - The in-place cipher operation is
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* achieved by the following operation:
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*
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* TX SGL: AAD || PT
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* | |
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* | copy |
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* v v
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* RX SGL: AAD || PT || Tag
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*/
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err = crypto_aead_copy_sgl(null_tfm, tsgl_src,
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areq->first_rsgl.sgl.sg, processed);
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if (err)
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goto free;
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af_alg_pull_tsgl(sk, processed, NULL, 0);
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} else {
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/*
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* Decryption operation - To achieve an in-place cipher
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* operation, the following SGL structure is used:
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*
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* TX SGL: AAD || CT || Tag
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* | | ^
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* | copy | | Create SGL link.
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* v v |
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* RX SGL: AAD || CT ----+
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*/
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/* Copy AAD || CT to RX SGL buffer for in-place operation. */
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err = crypto_aead_copy_sgl(null_tfm, tsgl_src,
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areq->first_rsgl.sgl.sg, outlen);
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if (err)
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goto free;
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/* Create TX SGL for tag and chain it to RX SGL. */
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areq->tsgl_entries = af_alg_count_tsgl(sk, processed,
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processed - as);
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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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/* Release TX SGL, except for tag data and reassign tag data. */
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af_alg_pull_tsgl(sk, processed, areq->tsgl, processed - as);
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/* chain the areq TX SGL holding the tag with RX SGL */
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if (usedpages) {
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/* RX SGL present */
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struct af_alg_sgl *sgl_prev = &areq->last_rsgl->sgl;
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sg_unmark_end(sgl_prev->sg + sgl_prev->npages - 1);
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sg_chain(sgl_prev->sg, sgl_prev->npages + 1,
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areq->tsgl);
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} else
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/* no RX SGL present (e.g. authentication only) */
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rsgl_src = areq->tsgl;
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}
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/* Initialize the crypto operation */
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aead_request_set_crypt(&areq->cra_u.aead_req, rsgl_src,
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areq->first_rsgl.sgl.sg, used, ctx->iv);
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aead_request_set_ad(&areq->cra_u.aead_req, ctx->aead_assoclen);
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aead_request_set_tfm(&areq->cra_u.aead_req, tfm);
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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 = outlen;
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aead_request_set_callback(&areq->cra_u.aead_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 ? crypto_aead_encrypt(&areq->cra_u.aead_req) :
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crypto_aead_decrypt(&areq->cra_u.aead_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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aead_request_set_callback(&areq->cra_u.aead_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_aead_encrypt(&areq->cra_u.aead_req) :
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crypto_aead_decrypt(&areq->cra_u.aead_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 : outlen;
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}
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static int aead_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 = _aead_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 || err == -EBADMSG || !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_aead_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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.mmap = sock_no_mmap,
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.bind = sock_no_bind,
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.accept = sock_no_accept,
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.release = af_alg_release,
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.sendmsg = aead_sendmsg,
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.sendpage = af_alg_sendpage,
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.recvmsg = aead_recvmsg,
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.poll = af_alg_poll,
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};
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static int aead_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 aead_tfm *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_aead_get_flags(tfm->aead) & 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 aead_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 = aead_check_key(sock);
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if (err)
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return err;
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return aead_sendmsg(sock, msg, size);
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}
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static ssize_t aead_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 = aead_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 aead_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 = aead_check_key(sock);
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if (err)
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return err;
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return aead_recvmsg(sock, msg, ignored, flags);
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}
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static struct proto_ops algif_aead_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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.mmap = sock_no_mmap,
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.bind = sock_no_bind,
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.accept = sock_no_accept,
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.release = af_alg_release,
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.sendmsg = aead_sendmsg_nokey,
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.sendpage = aead_sendpage_nokey,
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.recvmsg = aead_recvmsg_nokey,
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.poll = af_alg_poll,
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};
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static void *aead_bind(const char *name, u32 type, u32 mask)
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{
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struct aead_tfm *tfm;
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struct crypto_aead *aead;
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struct crypto_sync_skcipher *null_tfm;
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tfm = kzalloc(sizeof(*tfm), GFP_KERNEL);
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if (!tfm)
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return ERR_PTR(-ENOMEM);
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aead = crypto_alloc_aead(name, type, mask);
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if (IS_ERR(aead)) {
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kfree(tfm);
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return ERR_CAST(aead);
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}
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null_tfm = crypto_get_default_null_skcipher();
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if (IS_ERR(null_tfm)) {
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crypto_free_aead(aead);
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kfree(tfm);
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return ERR_CAST(null_tfm);
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}
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tfm->aead = aead;
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tfm->null_tfm = null_tfm;
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return tfm;
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}
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|
static void aead_release(void *private)
|
|
{
|
|
struct aead_tfm *tfm = private;
|
|
|
|
crypto_free_aead(tfm->aead);
|
|
crypto_put_default_null_skcipher();
|
|
kfree(tfm);
|
|
}
|
|
|
|
static int aead_setauthsize(void *private, unsigned int authsize)
|
|
{
|
|
struct aead_tfm *tfm = private;
|
|
|
|
return crypto_aead_setauthsize(tfm->aead, authsize);
|
|
}
|
|
|
|
static int aead_setkey(void *private, const u8 *key, unsigned int keylen)
|
|
{
|
|
struct aead_tfm *tfm = private;
|
|
|
|
return crypto_aead_setkey(tfm->aead, key, keylen);
|
|
}
|
|
|
|
static void aead_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 aead_tfm *aeadc = pask->private;
|
|
struct crypto_aead *tfm = aeadc->aead;
|
|
unsigned int ivlen = crypto_aead_ivsize(tfm);
|
|
|
|
af_alg_pull_tsgl(sk, ctx->used, NULL, 0);
|
|
sock_kzfree_s(sk, ctx->iv, ivlen);
|
|
sock_kfree_s(sk, ctx, ctx->len);
|
|
af_alg_release_parent(sk);
|
|
}
|
|
|
|
static int aead_accept_parent_nokey(void *private, struct sock *sk)
|
|
{
|
|
struct af_alg_ctx *ctx;
|
|
struct alg_sock *ask = alg_sk(sk);
|
|
struct aead_tfm *tfm = private;
|
|
struct crypto_aead *aead = tfm->aead;
|
|
unsigned int len = sizeof(*ctx);
|
|
unsigned int ivlen = crypto_aead_ivsize(aead);
|
|
|
|
ctx = sock_kmalloc(sk, len, GFP_KERNEL);
|
|
if (!ctx)
|
|
return -ENOMEM;
|
|
memset(ctx, 0, len);
|
|
|
|
ctx->iv = sock_kmalloc(sk, ivlen, GFP_KERNEL);
|
|
if (!ctx->iv) {
|
|
sock_kfree_s(sk, ctx, len);
|
|
return -ENOMEM;
|
|
}
|
|
memset(ctx->iv, 0, ivlen);
|
|
|
|
INIT_LIST_HEAD(&ctx->tsgl_list);
|
|
ctx->len = len;
|
|
crypto_init_wait(&ctx->wait);
|
|
|
|
ask->private = ctx;
|
|
|
|
sk->sk_destruct = aead_sock_destruct;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int aead_accept_parent(void *private, struct sock *sk)
|
|
{
|
|
struct aead_tfm *tfm = private;
|
|
|
|
if (crypto_aead_get_flags(tfm->aead) & CRYPTO_TFM_NEED_KEY)
|
|
return -ENOKEY;
|
|
|
|
return aead_accept_parent_nokey(private, sk);
|
|
}
|
|
|
|
static const struct af_alg_type algif_type_aead = {
|
|
.bind = aead_bind,
|
|
.release = aead_release,
|
|
.setkey = aead_setkey,
|
|
.setauthsize = aead_setauthsize,
|
|
.accept = aead_accept_parent,
|
|
.accept_nokey = aead_accept_parent_nokey,
|
|
.ops = &algif_aead_ops,
|
|
.ops_nokey = &algif_aead_ops_nokey,
|
|
.name = "aead",
|
|
.owner = THIS_MODULE
|
|
};
|
|
|
|
static int __init algif_aead_init(void)
|
|
{
|
|
return af_alg_register_type(&algif_type_aead);
|
|
}
|
|
|
|
static void __exit algif_aead_exit(void)
|
|
{
|
|
int err = af_alg_unregister_type(&algif_type_aead);
|
|
BUG_ON(err);
|
|
}
|
|
|
|
module_init(algif_aead_init);
|
|
module_exit(algif_aead_exit);
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_AUTHOR("Stephan Mueller <smueller@chronox.de>");
|
|
MODULE_DESCRIPTION("AEAD kernel crypto API user space interface");
|