linux/crypto/algif_aead.c
Herbert Xu 3e90950d36 crypto: algif_aead - Temporarily disable all AEAD algorithms
As the AEAD conversion is still ongoing, we do not yet wish to
export legacy AEAD implementations to user-space, as their calling
convention will change.

This patch actually disables all AEAD algorithms because some of
them (e.g., cryptd) will need to be modified to propagate this flag.

Subsequent patches will reenable them on an individual basis.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2015-06-22 15:49:30 +08:00

616 lines
14 KiB
C

/*
* algif_aead: User-space interface for AEAD algorithms
*
* Copyright (C) 2014, Stephan Mueller <smueller@chronox.de>
*
* This file provides the user-space API for AEAD ciphers.
*
* This file is derived from algif_skcipher.c.
*
* 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/aead.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 aead_sg_list {
unsigned int cur;
struct scatterlist sg[ALG_MAX_PAGES];
};
struct aead_ctx {
struct aead_sg_list tsgl;
/*
* RSGL_MAX_ENTRIES is an artificial limit where user space at maximum
* can cause the kernel to allocate RSGL_MAX_ENTRIES * ALG_MAX_PAGES
* pages
*/
#define RSGL_MAX_ENTRIES ALG_MAX_PAGES
struct af_alg_sgl rsgl[RSGL_MAX_ENTRIES];
void *iv;
struct af_alg_completion completion;
unsigned long used;
unsigned int len;
bool more;
bool merge;
bool enc;
size_t aead_assoclen;
struct aead_request aead_req;
};
static inline int aead_sndbuf(struct sock *sk)
{
struct alg_sock *ask = alg_sk(sk);
struct aead_ctx *ctx = ask->private;
return max_t(int, max_t(int, sk->sk_sndbuf & PAGE_MASK, PAGE_SIZE) -
ctx->used, 0);
}
static inline bool aead_writable(struct sock *sk)
{
return PAGE_SIZE <= aead_sndbuf(sk);
}
static inline bool aead_sufficient_data(struct aead_ctx *ctx)
{
unsigned as = crypto_aead_authsize(crypto_aead_reqtfm(&ctx->aead_req));
return ctx->used >= ctx->aead_assoclen + as;
}
static void aead_put_sgl(struct sock *sk)
{
struct alg_sock *ask = alg_sk(sk);
struct aead_ctx *ctx = ask->private;
struct aead_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);
}
sgl->cur = 0;
ctx->used = 0;
ctx->more = 0;
ctx->merge = 0;
}
static void aead_wmem_wakeup(struct sock *sk)
{
struct socket_wq *wq;
if (!aead_writable(sk))
return;
rcu_read_lock();
wq = rcu_dereference(sk->sk_wq);
if (wq_has_sleeper(wq))
wake_up_interruptible_sync_poll(&wq->wait, POLLIN |
POLLRDNORM |
POLLRDBAND);
sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_IN);
rcu_read_unlock();
}
static int aead_wait_for_data(struct sock *sk, unsigned flags)
{
struct alg_sock *ask = alg_sk(sk);
struct aead_ctx *ctx = ask->private;
long timeout;
DEFINE_WAIT(wait);
int err = -ERESTARTSYS;
if (flags & MSG_DONTWAIT)
return -EAGAIN;
set_bit(SOCK_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(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
return err;
}
static void aead_data_wakeup(struct sock *sk)
{
struct alg_sock *ask = alg_sk(sk);
struct aead_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))
wake_up_interruptible_sync_poll(&wq->wait, POLLOUT |
POLLRDNORM |
POLLRDBAND);
sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT);
rcu_read_unlock();
}
static int aead_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)
{
struct sock *sk = sock->sk;
struct alg_sock *ask = alg_sk(sk);
struct aead_ctx *ctx = ask->private;
unsigned ivsize =
crypto_aead_ivsize(crypto_aead_reqtfm(&ctx->aead_req));
struct aead_sg_list *sgl = &ctx->tsgl;
struct af_alg_control con = {};
long copied = 0;
bool enc = 0;
bool init = 0;
int err = -EINVAL;
if (msg->msg_controllen) {
err = af_alg_cmsg_send(msg, &con);
if (err)
return err;
init = 1;
switch (con.op) {
case ALG_OP_ENCRYPT:
enc = 1;
break;
case ALG_OP_DECRYPT:
enc = 0;
break;
default:
return -EINVAL;
}
if (con.iv && con.iv->ivlen != ivsize)
return -EINVAL;
}
lock_sock(sk);
if (!ctx->more && ctx->used)
goto unlock;
if (init) {
ctx->enc = enc;
if (con.iv)
memcpy(ctx->iv, con.iv->iv, ivsize);
ctx->aead_assoclen = con.aead_assoclen;
}
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 (!aead_writable(sk)) {
/* user space sent too much data */
aead_put_sgl(sk);
err = -EMSGSIZE;
goto unlock;
}
/* allocate a new page */
len = min_t(unsigned long, size, aead_sndbuf(sk));
while (len) {
int plen = 0;
if (sgl->cur >= ALG_MAX_PAGES) {
aead_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));
err = -ENOMEM;
if (!sg_page(sg))
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;
if (!ctx->more && !aead_sufficient_data(ctx)) {
aead_put_sgl(sk);
err = -EMSGSIZE;
}
unlock:
aead_data_wakeup(sk);
release_sock(sk);
return err ?: copied;
}
static ssize_t aead_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 aead_ctx *ctx = ask->private;
struct aead_sg_list *sgl = &ctx->tsgl;
int err = -EINVAL;
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 (!aead_writable(sk)) {
/* user space sent too much data */
aead_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;
err = 0;
done:
ctx->more = flags & MSG_MORE;
if (!ctx->more && !aead_sufficient_data(ctx)) {
aead_put_sgl(sk);
err = -EMSGSIZE;
}
unlock:
aead_data_wakeup(sk);
release_sock(sk);
return err ?: size;
}
static int aead_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 aead_ctx *ctx = ask->private;
unsigned as = crypto_aead_authsize(crypto_aead_reqtfm(&ctx->aead_req));
struct aead_sg_list *sgl = &ctx->tsgl;
unsigned int i = 0;
int err = -EINVAL;
unsigned long used = 0;
size_t outlen = 0;
size_t usedpages = 0;
unsigned int cnt = 0;
/* Limit number of IOV blocks to be accessed below */
if (msg->msg_iter.nr_segs > RSGL_MAX_ENTRIES)
return -ENOMSG;
lock_sock(sk);
/*
* AEAD memory structure: For encryption, the tag is appended to the
* ciphertext which implies that the memory allocated for the ciphertext
* must be increased by the tag length. For decryption, the tag
* is expected to be concatenated to the ciphertext. The plaintext
* therefore has a memory size of the ciphertext minus the tag length.
*
* The memory structure for cipher operation has the following
* structure:
* AEAD encryption input: assoc data || plaintext
* AEAD encryption output: cipherntext || auth tag
* AEAD decryption input: assoc data || ciphertext || auth tag
* AEAD decryption output: plaintext
*/
if (ctx->more) {
err = aead_wait_for_data(sk, flags);
if (err)
goto unlock;
}
used = ctx->used;
/*
* Make sure sufficient data is present -- note, the same check is
* is also present in sendmsg/sendpage. The checks in sendpage/sendmsg
* shall provide an information to the data sender that something is
* wrong, but they are irrelevant to maintain the kernel integrity.
* We need this check here too in case user space decides to not honor
* the error message in sendmsg/sendpage and still call recvmsg. This
* check here protects the kernel integrity.
*/
if (!aead_sufficient_data(ctx))
goto unlock;
outlen = used;
/*
* The cipher operation input data is reduced by the associated data
* length as this data is processed separately later on.
*/
used -= ctx->aead_assoclen + (ctx->enc ? as : 0);
/* convert iovecs of output buffers into scatterlists */
while (iov_iter_count(&msg->msg_iter)) {
size_t seglen = min_t(size_t, iov_iter_count(&msg->msg_iter),
(outlen - usedpages));
/* make one iovec available as scatterlist */
err = af_alg_make_sg(&ctx->rsgl[cnt], &msg->msg_iter,
seglen);
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]);
/* we do not need more iovecs as we have sufficient memory */
if (outlen <= usedpages)
break;
iov_iter_advance(&msg->msg_iter, err);
cnt++;
}
err = -EINVAL;
/* ensure output buffer is sufficiently large */
if (usedpages < outlen)
goto unlock;
sg_mark_end(sgl->sg + sgl->cur - 1);
aead_request_set_crypt(&ctx->aead_req, sgl->sg, ctx->rsgl[0].sg,
used, ctx->iv);
aead_request_set_ad(&ctx->aead_req, ctx->aead_assoclen);
err = af_alg_wait_for_completion(ctx->enc ?
crypto_aead_encrypt(&ctx->aead_req) :
crypto_aead_decrypt(&ctx->aead_req),
&ctx->completion);
if (err) {
/* EBADMSG implies a valid cipher operation took place */
if (err == -EBADMSG)
aead_put_sgl(sk);
goto unlock;
}
aead_put_sgl(sk);
err = 0;
unlock:
for (i = 0; i < cnt; i++)
af_alg_free_sg(&ctx->rsgl[i]);
aead_wmem_wakeup(sk);
release_sock(sk);
return err ? err : outlen;
}
static unsigned int aead_poll(struct file *file, struct socket *sock,
poll_table *wait)
{
struct sock *sk = sock->sk;
struct alg_sock *ask = alg_sk(sk);
struct aead_ctx *ctx = ask->private;
unsigned int mask;
sock_poll_wait(file, sk_sleep(sk), wait);
mask = 0;
if (!ctx->more)
mask |= POLLIN | POLLRDNORM;
if (aead_writable(sk))
mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
return mask;
}
static struct proto_ops algif_aead_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 = aead_sendmsg,
.sendpage = aead_sendpage,
.recvmsg = aead_recvmsg,
.poll = aead_poll,
};
static void *aead_bind(const char *name, u32 type, u32 mask)
{
return crypto_alloc_aead(name, type | CRYPTO_ALG_AEAD_NEW,
mask | CRYPTO_ALG_AEAD_NEW);
}
static void aead_release(void *private)
{
crypto_free_aead(private);
}
static int aead_setauthsize(void *private, unsigned int authsize)
{
return crypto_aead_setauthsize(private, authsize);
}
static int aead_setkey(void *private, const u8 *key, unsigned int keylen)
{
return crypto_aead_setkey(private, key, keylen);
}
static void aead_sock_destruct(struct sock *sk)
{
struct alg_sock *ask = alg_sk(sk);
struct aead_ctx *ctx = ask->private;
unsigned int ivlen = crypto_aead_ivsize(
crypto_aead_reqtfm(&ctx->aead_req));
aead_put_sgl(sk);
sock_kzfree_s(sk, ctx->iv, ivlen);
sock_kfree_s(sk, ctx, ctx->len);
af_alg_release_parent(sk);
}
static int aead_accept_parent(void *private, struct sock *sk)
{
struct aead_ctx *ctx;
struct alg_sock *ask = alg_sk(sk);
unsigned int len = sizeof(*ctx) + crypto_aead_reqsize(private);
unsigned int ivlen = crypto_aead_ivsize(private);
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);
ctx->len = len;
ctx->used = 0;
ctx->more = 0;
ctx->merge = 0;
ctx->enc = 0;
ctx->tsgl.cur = 0;
ctx->aead_assoclen = 0;
af_alg_init_completion(&ctx->completion);
sg_init_table(ctx->tsgl.sg, ALG_MAX_PAGES);
ask->private = ctx;
aead_request_set_tfm(&ctx->aead_req, private);
aead_request_set_callback(&ctx->aead_req, CRYPTO_TFM_REQ_MAY_BACKLOG,
af_alg_complete, &ctx->completion);
sk->sk_destruct = aead_sock_destruct;
return 0;
}
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,
.ops = &algif_aead_ops,
.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");