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af_alg.c
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af_alg.c
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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* af_alg: User-space algorithm interface
*
* This file provides the user-space API for algorithms.
*
* Copyright (c) 2010 Herbert Xu <[email protected]>
*/
#include <linux/atomic.h>
#include <crypto/if_alg.h>
#include <linux/crypto.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/net.h>
#include <linux/rwsem.h>
#include <linux/sched.h>
#include <linux/sched/signal.h>
#include <linux/security.h>
struct alg_type_list {
const struct af_alg_type *type;
struct list_head list;
};
static atomic_long_t alg_memory_allocated;
static struct proto alg_proto = {
.name = "ALG",
.owner = THIS_MODULE,
.memory_allocated = &alg_memory_allocated,
.obj_size = sizeof(struct alg_sock),
};
static LIST_HEAD(alg_types);
static DECLARE_RWSEM(alg_types_sem);
static const struct af_alg_type *alg_get_type(const char *name)
{
const struct af_alg_type *type = ERR_PTR(-ENOENT);
struct alg_type_list *node;
down_read(&alg_types_sem);
list_for_each_entry(node, &alg_types, list) {
if (strcmp(node->type->name, name))
continue;
if (try_module_get(node->type->owner))
type = node->type;
break;
}
up_read(&alg_types_sem);
return type;
}
int af_alg_register_type(const struct af_alg_type *type)
{
struct alg_type_list *node;
int err = -EEXIST;
down_write(&alg_types_sem);
list_for_each_entry(node, &alg_types, list) {
if (!strcmp(node->type->name, type->name))
goto unlock;
}
node = kmalloc(sizeof(*node), GFP_KERNEL);
err = -ENOMEM;
if (!node)
goto unlock;
type->ops->owner = THIS_MODULE;
if (type->ops_nokey)
type->ops_nokey->owner = THIS_MODULE;
node->type = type;
list_add(&node->list, &alg_types);
err = 0;
unlock:
up_write(&alg_types_sem);
return err;
}
EXPORT_SYMBOL_GPL(af_alg_register_type);
int af_alg_unregister_type(const struct af_alg_type *type)
{
struct alg_type_list *node;
int err = -ENOENT;
down_write(&alg_types_sem);
list_for_each_entry(node, &alg_types, list) {
if (strcmp(node->type->name, type->name))
continue;
list_del(&node->list);
kfree(node);
err = 0;
break;
}
up_write(&alg_types_sem);
return err;
}
EXPORT_SYMBOL_GPL(af_alg_unregister_type);
static void alg_do_release(const struct af_alg_type *type, void *private)
{
if (!type)
return;
type->release(private);
module_put(type->owner);
}
int af_alg_release(struct socket *sock)
{
if (sock->sk) {
sock_put(sock->sk);
sock->sk = NULL;
}
return 0;
}
EXPORT_SYMBOL_GPL(af_alg_release);
void af_alg_release_parent(struct sock *sk)
{
struct alg_sock *ask = alg_sk(sk);
unsigned int nokey = atomic_read(&ask->nokey_refcnt);
sk = ask->parent;
ask = alg_sk(sk);
if (nokey)
atomic_dec(&ask->nokey_refcnt);
if (atomic_dec_and_test(&ask->refcnt))
sock_put(sk);
}
EXPORT_SYMBOL_GPL(af_alg_release_parent);
static int alg_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
{
const u32 allowed = CRYPTO_ALG_KERN_DRIVER_ONLY;
struct sock *sk = sock->sk;
struct alg_sock *ask = alg_sk(sk);
struct sockaddr_alg_new *sa = (void *)uaddr;
const struct af_alg_type *type;
void *private;
int err;
if (sock->state == SS_CONNECTED)
return -EINVAL;
BUILD_BUG_ON(offsetof(struct sockaddr_alg_new, salg_name) !=
offsetof(struct sockaddr_alg, salg_name));
BUILD_BUG_ON(offsetof(struct sockaddr_alg, salg_name) != sizeof(*sa));
if (addr_len < sizeof(*sa) + 1)
return -EINVAL;
/* If caller uses non-allowed flag, return error. */
if ((sa->salg_feat & ~allowed) || (sa->salg_mask & ~allowed))
return -EINVAL;
sa->salg_type[sizeof(sa->salg_type) - 1] = 0;
sa->salg_name[addr_len - sizeof(*sa) - 1] = 0;
type = alg_get_type(sa->salg_type);
if (PTR_ERR(type) == -ENOENT) {
request_module("algif-%s", sa->salg_type);
type = alg_get_type(sa->salg_type);
}
if (IS_ERR(type))
return PTR_ERR(type);
private = type->bind(sa->salg_name, sa->salg_feat, sa->salg_mask);
if (IS_ERR(private)) {
module_put(type->owner);
return PTR_ERR(private);
}
err = -EBUSY;
lock_sock(sk);
if (atomic_read(&ask->refcnt))
goto unlock;
swap(ask->type, type);
swap(ask->private, private);
err = 0;
unlock:
release_sock(sk);
alg_do_release(type, private);
return err;
}
static int alg_setkey(struct sock *sk, sockptr_t ukey, unsigned int keylen)
{
struct alg_sock *ask = alg_sk(sk);
const struct af_alg_type *type = ask->type;
u8 *key;
int err;
key = sock_kmalloc(sk, keylen, GFP_KERNEL);
if (!key)
return -ENOMEM;
err = -EFAULT;
if (copy_from_sockptr(key, ukey, keylen))
goto out;
err = type->setkey(ask->private, key, keylen);
out:
sock_kzfree_s(sk, key, keylen);
return err;
}
static int alg_setsockopt(struct socket *sock, int level, int optname,
sockptr_t optval, unsigned int optlen)
{
struct sock *sk = sock->sk;
struct alg_sock *ask = alg_sk(sk);
const struct af_alg_type *type;
int err = -EBUSY;
lock_sock(sk);
if (atomic_read(&ask->refcnt) != atomic_read(&ask->nokey_refcnt))
goto unlock;
type = ask->type;
err = -ENOPROTOOPT;
if (level != SOL_ALG || !type)
goto unlock;
switch (optname) {
case ALG_SET_KEY:
if (sock->state == SS_CONNECTED)
goto unlock;
if (!type->setkey)
goto unlock;
err = alg_setkey(sk, optval, optlen);
break;
case ALG_SET_AEAD_AUTHSIZE:
if (sock->state == SS_CONNECTED)
goto unlock;
if (!type->setauthsize)
goto unlock;
err = type->setauthsize(ask->private, optlen);
break;
case ALG_SET_DRBG_ENTROPY:
if (sock->state == SS_CONNECTED)
goto unlock;
if (!type->setentropy)
goto unlock;
err = type->setentropy(ask->private, optval, optlen);
}
unlock:
release_sock(sk);
return err;
}
int af_alg_accept(struct sock *sk, struct socket *newsock, bool kern)
{
struct alg_sock *ask = alg_sk(sk);
const struct af_alg_type *type;
struct sock *sk2;
unsigned int nokey;
int err;
lock_sock(sk);
type = ask->type;
err = -EINVAL;
if (!type)
goto unlock;
sk2 = sk_alloc(sock_net(sk), PF_ALG, GFP_KERNEL, &alg_proto, kern);
err = -ENOMEM;
if (!sk2)
goto unlock;
sock_init_data(newsock, sk2);
security_sock_graft(sk2, newsock);
security_sk_clone(sk, sk2);
/*
* newsock->ops assigned here to allow type->accept call to override
* them when required.
*/
newsock->ops = type->ops;
err = type->accept(ask->private, sk2);
nokey = err == -ENOKEY;
if (nokey && type->accept_nokey)
err = type->accept_nokey(ask->private, sk2);
if (err)
goto unlock;
if (atomic_inc_return_relaxed(&ask->refcnt) == 1)
sock_hold(sk);
if (nokey) {
atomic_inc(&ask->nokey_refcnt);
atomic_set(&alg_sk(sk2)->nokey_refcnt, 1);
}
alg_sk(sk2)->parent = sk;
alg_sk(sk2)->type = type;
newsock->state = SS_CONNECTED;
if (nokey)
newsock->ops = type->ops_nokey;
err = 0;
unlock:
release_sock(sk);
return err;
}
EXPORT_SYMBOL_GPL(af_alg_accept);
static int alg_accept(struct socket *sock, struct socket *newsock, int flags,
bool kern)
{
return af_alg_accept(sock->sk, newsock, kern);
}
static const struct proto_ops alg_proto_ops = {
.family = PF_ALG,
.owner = THIS_MODULE,
.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,
.sendpage = sock_no_sendpage,
.sendmsg = sock_no_sendmsg,
.recvmsg = sock_no_recvmsg,
.bind = alg_bind,
.release = af_alg_release,
.setsockopt = alg_setsockopt,
.accept = alg_accept,
};
static void alg_sock_destruct(struct sock *sk)
{
struct alg_sock *ask = alg_sk(sk);
alg_do_release(ask->type, ask->private);
}
static int alg_create(struct net *net, struct socket *sock, int protocol,
int kern)
{
struct sock *sk;
int err;
if (sock->type != SOCK_SEQPACKET)
return -ESOCKTNOSUPPORT;
if (protocol != 0)
return -EPROTONOSUPPORT;
err = -ENOMEM;
sk = sk_alloc(net, PF_ALG, GFP_KERNEL, &alg_proto, kern);
if (!sk)
goto out;
sock->ops = &alg_proto_ops;
sock_init_data(sock, sk);
sk->sk_destruct = alg_sock_destruct;
return 0;
out:
return err;
}
static const struct net_proto_family alg_family = {
.family = PF_ALG,
.create = alg_create,
.owner = THIS_MODULE,
};
int af_alg_make_sg(struct af_alg_sgl *sgl, struct iov_iter *iter, int len)
{
size_t off;
ssize_t n;
int npages, i;
n = iov_iter_get_pages(iter, sgl->pages, len, ALG_MAX_PAGES, &off);
if (n < 0)
return n;
npages = DIV_ROUND_UP(off + n, PAGE_SIZE);
if (WARN_ON(npages == 0))
return -EINVAL;
/* Add one extra for linking */
sg_init_table(sgl->sg, npages + 1);
for (i = 0, len = n; i < npages; i++) {
int plen = min_t(int, len, PAGE_SIZE - off);
sg_set_page(sgl->sg + i, sgl->pages[i], plen, off);
off = 0;
len -= plen;
}
sg_mark_end(sgl->sg + npages - 1);
sgl->npages = npages;
return n;
}
EXPORT_SYMBOL_GPL(af_alg_make_sg);
static void af_alg_link_sg(struct af_alg_sgl *sgl_prev,
struct af_alg_sgl *sgl_new)
{
sg_unmark_end(sgl_prev->sg + sgl_prev->npages - 1);
sg_chain(sgl_prev->sg, sgl_prev->npages + 1, sgl_new->sg);
}
void af_alg_free_sg(struct af_alg_sgl *sgl)
{
int i;
for (i = 0; i < sgl->npages; i++)
put_page(sgl->pages[i]);
}
EXPORT_SYMBOL_GPL(af_alg_free_sg);
static int af_alg_cmsg_send(struct msghdr *msg, struct af_alg_control *con)
{
struct cmsghdr *cmsg;
for_each_cmsghdr(cmsg, msg) {
if (!CMSG_OK(msg, cmsg))
return -EINVAL;
if (cmsg->cmsg_level != SOL_ALG)
continue;
switch (cmsg->cmsg_type) {
case ALG_SET_IV:
if (cmsg->cmsg_len < CMSG_LEN(sizeof(*con->iv)))
return -EINVAL;
con->iv = (void *)CMSG_DATA(cmsg);
if (cmsg->cmsg_len < CMSG_LEN(con->iv->ivlen +
sizeof(*con->iv)))
return -EINVAL;
break;
case ALG_SET_OP:
if (cmsg->cmsg_len < CMSG_LEN(sizeof(u32)))
return -EINVAL;
con->op = *(u32 *)CMSG_DATA(cmsg);
break;
case ALG_SET_AEAD_ASSOCLEN:
if (cmsg->cmsg_len < CMSG_LEN(sizeof(u32)))
return -EINVAL;
con->aead_assoclen = *(u32 *)CMSG_DATA(cmsg);
break;
default:
return -EINVAL;
}
}
return 0;
}
/**
* af_alg_alloc_tsgl - allocate the TX SGL
*
* @sk: socket of connection to user space
* Return: 0 upon success, < 0 upon error
*/
static int af_alg_alloc_tsgl(struct sock *sk)
{
struct alg_sock *ask = alg_sk(sk);
struct af_alg_ctx *ctx = ask->private;
struct af_alg_tsgl *sgl;
struct scatterlist *sg = NULL;
sgl = list_entry(ctx->tsgl_list.prev, struct af_alg_tsgl, list);
if (!list_empty(&ctx->tsgl_list))
sg = sgl->sg;
if (!sg || sgl->cur >= MAX_SGL_ENTS) {
sgl = sock_kmalloc(sk,
struct_size(sgl, sg, (MAX_SGL_ENTS + 1)),
GFP_KERNEL);
if (!sgl)
return -ENOMEM;
sg_init_table(sgl->sg, MAX_SGL_ENTS + 1);
sgl->cur = 0;
if (sg)
sg_chain(sg, MAX_SGL_ENTS + 1, sgl->sg);
list_add_tail(&sgl->list, &ctx->tsgl_list);
}
return 0;
}
/**
* af_alg_count_tsgl - Count number of TX SG entries
*
* The counting starts from the beginning of the SGL to @bytes. If
* an @offset is provided, the counting of the SG entries starts at the @offset.
*
* @sk: socket of connection to user space
* @bytes: Count the number of SG entries holding given number of bytes.
* @offset: Start the counting of SG entries from the given offset.
* Return: Number of TX SG entries found given the constraints
*/
unsigned int af_alg_count_tsgl(struct sock *sk, size_t bytes, size_t offset)
{
const struct alg_sock *ask = alg_sk(sk);
const struct af_alg_ctx *ctx = ask->private;
const struct af_alg_tsgl *sgl;
unsigned int i;
unsigned int sgl_count = 0;
if (!bytes)
return 0;
list_for_each_entry(sgl, &ctx->tsgl_list, list) {
const struct scatterlist *sg = sgl->sg;
for (i = 0; i < sgl->cur; i++) {
size_t bytes_count;
/* Skip offset */
if (offset >= sg[i].length) {
offset -= sg[i].length;
bytes -= sg[i].length;
continue;
}
bytes_count = sg[i].length - offset;
offset = 0;
sgl_count++;
/* If we have seen requested number of bytes, stop */
if (bytes_count >= bytes)
return sgl_count;
bytes -= bytes_count;
}
}
return sgl_count;
}
EXPORT_SYMBOL_GPL(af_alg_count_tsgl);
/**
* af_alg_pull_tsgl - Release the specified buffers from TX SGL
*
* If @dst is non-null, reassign the pages to @dst. The caller must release
* the pages. If @dst_offset is given only reassign the pages to @dst starting
* at the @dst_offset (byte). The caller must ensure that @dst is large
* enough (e.g. by using af_alg_count_tsgl with the same offset).
*
* @sk: socket of connection to user space
* @used: Number of bytes to pull from TX SGL
* @dst: If non-NULL, buffer is reassigned to dst SGL instead of releasing. The
* caller must release the buffers in dst.
* @dst_offset: Reassign the TX SGL from given offset. All buffers before
* reaching the offset is released.
*/
void af_alg_pull_tsgl(struct sock *sk, size_t used, struct scatterlist *dst,
size_t dst_offset)
{
struct alg_sock *ask = alg_sk(sk);
struct af_alg_ctx *ctx = ask->private;
struct af_alg_tsgl *sgl;
struct scatterlist *sg;
unsigned int i, j = 0;
while (!list_empty(&ctx->tsgl_list)) {
sgl = list_first_entry(&ctx->tsgl_list, struct af_alg_tsgl,
list);
sg = sgl->sg;
for (i = 0; i < sgl->cur; i++) {
size_t plen = min_t(size_t, used, sg[i].length);
struct page *page = sg_page(sg + i);
if (!page)
continue;
/*
* Assumption: caller created af_alg_count_tsgl(len)
* SG entries in dst.
*/
if (dst) {
if (dst_offset >= plen) {
/* discard page before offset */
dst_offset -= plen;
} else {
/* reassign page to dst after offset */
get_page(page);
sg_set_page(dst + j, page,
plen - dst_offset,
sg[i].offset + dst_offset);
dst_offset = 0;
j++;
}
}
sg[i].length -= plen;
sg[i].offset += plen;
used -= plen;
ctx->used -= plen;
if (sg[i].length)
return;
put_page(page);
sg_assign_page(sg + i, NULL);
}
list_del(&sgl->list);
sock_kfree_s(sk, sgl, struct_size(sgl, sg, MAX_SGL_ENTS + 1));
}
if (!ctx->used)
ctx->merge = 0;
ctx->init = ctx->more;
}
EXPORT_SYMBOL_GPL(af_alg_pull_tsgl);
/**
* af_alg_free_areq_sgls - Release TX and RX SGLs of the request
*
* @areq: Request holding the TX and RX SGL
*/
static void af_alg_free_areq_sgls(struct af_alg_async_req *areq)
{
struct sock *sk = areq->sk;
struct alg_sock *ask = alg_sk(sk);
struct af_alg_ctx *ctx = ask->private;
struct af_alg_rsgl *rsgl, *tmp;
struct scatterlist *tsgl;
struct scatterlist *sg;
unsigned int i;
list_for_each_entry_safe(rsgl, tmp, &areq->rsgl_list, list) {
atomic_sub(rsgl->sg_num_bytes, &ctx->rcvused);
af_alg_free_sg(&rsgl->sgl);
list_del(&rsgl->list);
if (rsgl != &areq->first_rsgl)
sock_kfree_s(sk, rsgl, sizeof(*rsgl));
}
tsgl = areq->tsgl;
if (tsgl) {
for_each_sg(tsgl, sg, areq->tsgl_entries, i) {
if (!sg_page(sg))
continue;
put_page(sg_page(sg));
}
sock_kfree_s(sk, tsgl, areq->tsgl_entries * sizeof(*tsgl));
}
}
/**
* af_alg_wait_for_wmem - wait for availability of writable memory
*
* @sk: socket of connection to user space
* @flags: If MSG_DONTWAIT is set, then only report if function would sleep
* Return: 0 when writable memory is available, < 0 upon error
*/
static int af_alg_wait_for_wmem(struct sock *sk, unsigned int flags)
{
DEFINE_WAIT_FUNC(wait, woken_wake_function);
int err = -ERESTARTSYS;
long timeout;
if (flags & MSG_DONTWAIT)
return -EAGAIN;
sk_set_bit(SOCKWQ_ASYNC_NOSPACE, sk);
add_wait_queue(sk_sleep(sk), &wait);
for (;;) {
if (signal_pending(current))
break;
timeout = MAX_SCHEDULE_TIMEOUT;
if (sk_wait_event(sk, &timeout, af_alg_writable(sk), &wait)) {
err = 0;
break;
}
}
remove_wait_queue(sk_sleep(sk), &wait);
return err;
}
/**
* af_alg_wmem_wakeup - wakeup caller when writable memory is available
*
* @sk: socket of connection to user space
*/
void af_alg_wmem_wakeup(struct sock *sk)
{
struct socket_wq *wq;
if (!af_alg_writable(sk))
return;
rcu_read_lock();
wq = rcu_dereference(sk->sk_wq);
if (skwq_has_sleeper(wq))
wake_up_interruptible_sync_poll(&wq->wait, EPOLLIN |
EPOLLRDNORM |
EPOLLRDBAND);
sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_IN);
rcu_read_unlock();
}
EXPORT_SYMBOL_GPL(af_alg_wmem_wakeup);
/**
* af_alg_wait_for_data - wait for availability of TX data
*
* @sk: socket of connection to user space
* @flags: If MSG_DONTWAIT is set, then only report if function would sleep
* @min: Set to minimum request size if partial requests are allowed.
* Return: 0 when writable memory is available, < 0 upon error
*/
int af_alg_wait_for_data(struct sock *sk, unsigned flags, unsigned min)
{
DEFINE_WAIT_FUNC(wait, woken_wake_function);
struct alg_sock *ask = alg_sk(sk);
struct af_alg_ctx *ctx = ask->private;
long timeout;
int err = -ERESTARTSYS;
if (flags & MSG_DONTWAIT)
return -EAGAIN;
sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);
add_wait_queue(sk_sleep(sk), &wait);
for (;;) {
if (signal_pending(current))
break;
timeout = MAX_SCHEDULE_TIMEOUT;
if (sk_wait_event(sk, &timeout,
ctx->init && (!ctx->more ||
(min && ctx->used >= min)),
&wait)) {
err = 0;
break;
}
}
remove_wait_queue(sk_sleep(sk), &wait);
sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk);
return err;
}
EXPORT_SYMBOL_GPL(af_alg_wait_for_data);
/**
* af_alg_data_wakeup - wakeup caller when new data can be sent to kernel
*
* @sk: socket of connection to user space
*/
static void af_alg_data_wakeup(struct sock *sk)
{
struct alg_sock *ask = alg_sk(sk);
struct af_alg_ctx *ctx = ask->private;
struct socket_wq *wq;
if (!ctx->used)
return;
rcu_read_lock();
wq = rcu_dereference(sk->sk_wq);
if (skwq_has_sleeper(wq))
wake_up_interruptible_sync_poll(&wq->wait, EPOLLOUT |
EPOLLRDNORM |
EPOLLRDBAND);
sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT);
rcu_read_unlock();
}
/**
* af_alg_sendmsg - implementation of sendmsg system call handler
*
* The sendmsg system call handler obtains the user data and stores it
* in ctx->tsgl_list. This implies allocation of the required numbers of
* struct af_alg_tsgl.
*
* In addition, the ctx is filled with the information sent via CMSG.
*
* @sock: socket of connection to user space
* @msg: message from user space
* @size: size of message from user space
* @ivsize: the size of the IV for the cipher operation to verify that the
* user-space-provided IV has the right size
* Return: the number of copied data upon success, < 0 upon error
*/
int af_alg_sendmsg(struct socket *sock, struct msghdr *msg, size_t size,
unsigned int ivsize)
{
struct sock *sk = sock->sk;
struct alg_sock *ask = alg_sk(sk);
struct af_alg_ctx *ctx = ask->private;
struct af_alg_tsgl *sgl;
struct af_alg_control con = {};
long copied = 0;
bool enc = false;
bool init = false;
int err = 0;
if (msg->msg_controllen) {
err = af_alg_cmsg_send(msg, &con);
if (err)
return err;
init = true;
switch (con.op) {
case ALG_OP_ENCRYPT:
enc = true;
break;
case ALG_OP_DECRYPT:
enc = false;
break;
default:
return -EINVAL;
}
if (con.iv && con.iv->ivlen != ivsize)
return -EINVAL;
}
lock_sock(sk);
if (ctx->init && !ctx->more) {
if (ctx->used) {
err = -EINVAL;
goto unlock;
}
pr_info_once(
"%s sent an empty control message without MSG_MORE.\n",
current->comm);
}
ctx->init = true;
if (init) {
ctx->enc = enc;
if (con.iv)
memcpy(ctx->iv, con.iv->iv, ivsize);
ctx->aead_assoclen = con.aead_assoclen;
}
while (size) {
struct scatterlist *sg;
size_t len = size;
size_t plen;
/* use the existing memory in an allocated page */
if (ctx->merge) {
sgl = list_entry(ctx->tsgl_list.prev,
struct af_alg_tsgl, list);
sg = sgl->sg + sgl->cur - 1;
len = min_t(size_t, 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 (!af_alg_writable(sk)) {
err = af_alg_wait_for_wmem(sk, msg->msg_flags);
if (err)
goto unlock;
}
/* allocate a new page */
len = min_t(unsigned long, len, af_alg_sndbuf(sk));
err = af_alg_alloc_tsgl(sk);
if (err)
goto unlock;
sgl = list_entry(ctx->tsgl_list.prev, struct af_alg_tsgl,
list);
sg = sgl->sg;
if (sgl->cur)
sg_unmark_end(sg + sgl->cur - 1);
do {
unsigned int i = sgl->cur;
plen = min_t(size_t, len, PAGE_SIZE);
sg_assign_page(sg + i, alloc_page(GFP_KERNEL));
if (!sg_page(sg + i)) {
err = -ENOMEM;
goto unlock;
}
err = memcpy_from_msg(page_address(sg_page(sg + i)),
msg, plen);
if (err) {
__free_page(sg_page(sg + i));
sg_assign_page(sg + i, NULL);
goto unlock;
}
sg[i].length = plen;
len -= plen;
ctx->used += plen;
copied += plen;
size -= plen;
sgl->cur++;
} while (len && sgl->cur < MAX_SGL_ENTS);
if (!size)
sg_mark_end(sg + sgl->cur - 1);
ctx->merge = plen & (PAGE_SIZE - 1);
}
err = 0;
ctx->more = msg->msg_flags & MSG_MORE;
unlock:
af_alg_data_wakeup(sk);
release_sock(sk);
return copied ?: err;
}
EXPORT_SYMBOL_GPL(af_alg_sendmsg);
/**
* af_alg_sendpage - sendpage system call handler
* @sock: socket of connection to user space to write to
* @page: data to send
* @offset: offset into page to begin sending
* @size: length of data
* @flags: message send/receive flags
*
* This is a generic implementation of sendpage to fill ctx->tsgl_list.
*/
ssize_t af_alg_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 af_alg_ctx *ctx = ask->private;
struct af_alg_tsgl *sgl;
int err = -EINVAL;
if (flags & MSG_SENDPAGE_NOTLAST)
flags |= MSG_MORE;
lock_sock(sk);