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/*
* Driver for /dev/crypto device (aka CryptoDev)
*
* Copyright (c) 2009-2013 Nikos Mavrogiannopoulos <nmav@gnutls.org>
* Copyright (c) 2010 Phil Sutter
* Copyright (c) 2011, 2012 OpenSSL Software Foundation, Inc.
*
* This file is part of linux cryptodev.
*
* 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.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301, USA.
*/
#include <crypto/hash.h>
#include <linux/crypto.h>
#include <linux/mm.h>
#include <linux/highmem.h>
#include <linux/ioctl.h>
#include <linux/random.h>
#include <linux/syscalls.h>
#include <linux/pagemap.h>
#include <linux/uaccess.h>
#include <crypto/scatterwalk.h>
#include <linux/scatterlist.h>
#include "cryptodev_int.h"
#include "zc.h"
#include "version.h"
/* Helper functions to assist zero copy.
* This needs to be redesigned and moved out of the session. --nmav
*/
/* offset of buf in it's first page */
#define PAGEOFFSET(buf) ((unsigned long)buf & ~PAGE_MASK)
/* fetch the pages addr resides in into pg and initialise sg with them */
int __get_userbuf(uint8_t __user *addr, uint32_t len, int write,
unsigned int pgcount, struct page **pg, struct scatterlist *sg,
struct task_struct *task, struct mm_struct *mm)
{
int ret, pglen, i = 0;
struct scatterlist *sgp;
if (unlikely(!pgcount || !len || !addr)) {
sg_mark_end(sg);
return 0;
}
down_read(&mm->mmap_sem);
ret = get_user_pages(task, mm,
(unsigned long)addr, pgcount, write, 0, pg, NULL);
up_read(&mm->mmap_sem);
if (ret != pgcount)
return -EINVAL;
sg_init_table(sg, pgcount);
pglen = min((ptrdiff_t)(PAGE_SIZE - PAGEOFFSET(addr)), (ptrdiff_t)len);
sg_set_page(sg, pg[i++], pglen, PAGEOFFSET(addr));
len -= pglen;
for (sgp = sg_next(sg); len; sgp = sg_next(sgp)) {
pglen = min((uint32_t)PAGE_SIZE, len);
sg_set_page(sgp, pg[i++], pglen, 0);
len -= pglen;
}
sg_mark_end(sg_last(sg, pgcount));
return 0;
}
int adjust_sg_array(struct csession *ses, int pagecount)
{
struct scatterlist *sg;
struct page **pages;
int array_size;
for (array_size = ses->array_size; array_size < pagecount;
array_size *= 2)
;
ddebug(0, "reallocating from %d to %d pages",
ses->array_size, array_size);
pages = krealloc(ses->pages, array_size * sizeof(struct page *),
GFP_KERNEL);
if (unlikely(!pages))
return -ENOMEM;
ses->pages = pages;
sg = krealloc(ses->sg, array_size * sizeof(struct scatterlist),
GFP_KERNEL);
if (unlikely(!sg))
return -ENOMEM;
ses->sg = sg;
ses->array_size = array_size;
return 0;
}
void release_user_pages(struct csession *ses)
{
unsigned int i;
for (i = 0; i < ses->used_pages; i++) {
if (!PageReserved(ses->pages[i]))
SetPageDirty(ses->pages[i]);
if (ses->readonly_pages == 0)
flush_dcache_page(ses->pages[i]);
else
ses->readonly_pages--;
page_cache_release(ses->pages[i]);
}
ses->used_pages = 0;
}
/* make src and dst available in scatterlists.
* dst might be the same as src.
*/
int get_userbuf(struct csession *ses,
void *__user src, unsigned int src_len,
void *__user dst, unsigned int dst_len,
struct task_struct *task, struct mm_struct *mm,
struct scatterlist **src_sg,
struct scatterlist **dst_sg)
{
int src_pagecount, dst_pagecount;
int rc;
/* Empty input is a valid option to many algorithms & is tested by NIST/FIPS */
/* Make sure NULL input has 0 length */
if (!src && src_len)
src_len = 0;
/* I don't know that null output is ever useful, but we can handle it gracefully */
/* Make sure NULL output has 0 length */
if (!dst && dst_len)
dst_len = 0;
src_pagecount = PAGECOUNT(src, src_len);
dst_pagecount = PAGECOUNT(dst, dst_len);
ses->used_pages = (src == dst) ? max(src_pagecount, dst_pagecount)
: src_pagecount + dst_pagecount;
ses->readonly_pages = (src == dst) ? 0 : src_pagecount;
if (ses->used_pages > ses->array_size) {
rc = adjust_sg_array(ses, ses->used_pages);
if (rc)
return rc;
}
if (src == dst) { /* inplace operation */
rc = __get_userbuf(src, src_len, 1, ses->used_pages,
ses->pages, ses->sg, task, mm);
if (unlikely(rc)) {
derr(1, "failed to get user pages for data IO");
return rc;
}
(*src_sg) = (*dst_sg) = ses->sg;
return 0;
}
*src_sg = NULL; /* default to no input */
*dst_sg = NULL; /* default to ignore output */
if (likely(src)) {
rc = __get_userbuf(src, src_len, 0, ses->readonly_pages,
ses->pages, ses->sg, task, mm);
if (unlikely(rc)) {
derr(1, "failed to get user pages for data input");
return rc;
}
*src_sg = ses->sg;
}
if (likely(dst)) {
const unsigned int writable_pages =
ses->used_pages - ses->readonly_pages;
struct page **dst_pages = ses->pages + ses->readonly_pages;
*dst_sg = ses->sg + ses->readonly_pages;
rc = __get_userbuf(dst, dst_len, 1, writable_pages,
dst_pages, *dst_sg, task, mm);
if (unlikely(rc)) {
derr(1, "failed to get user pages for data output");
release_user_pages(ses); /* FIXME: use __release_userbuf(src, ...) */
return rc;
}
}
return 0;
}
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