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/*
* Block chaining cipher operations.
*
* Generic encrypt/decrypt wrapper for ciphers, handles operations across
* multiple page boundaries by using temporary blocks. In user context,
* the kernel is given a chance to schedule us once per page.
*
* Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au>
*
* 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 <linux/crypto.h>
#include <linux/errno.h>
#include <linux/hardirq.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/scatterlist.h>
#include <linux/seq_file.h>
#include <linux/slab.h>
#include <linux/string.h>
#include "internal.h"
#include "scatterwalk.h"
enum {
BLKCIPHER_WALK_PHYS = 1 << 0,
BLKCIPHER_WALK_SLOW = 1 << 1,
BLKCIPHER_WALK_COPY = 1 << 2,
BLKCIPHER_WALK_DIFF = 1 << 3,
};
static int blkcipher_walk_next(struct blkcipher_desc *desc,
struct blkcipher_walk *walk);
static int blkcipher_walk_first(struct blkcipher_desc *desc,
struct blkcipher_walk *walk);
static inline void blkcipher_map_src(struct blkcipher_walk *walk)
{
walk->src.virt.addr = scatterwalk_map(&walk->in, 0);
}
static inline void blkcipher_map_dst(struct blkcipher_walk *walk)
{
walk->dst.virt.addr = scatterwalk_map(&walk->out, 1);
}
static inline void blkcipher_unmap_src(struct blkcipher_walk *walk)
{
scatterwalk_unmap(walk->src.virt.addr, 0);
}
static inline void blkcipher_unmap_dst(struct blkcipher_walk *walk)
{
scatterwalk_unmap(walk->dst.virt.addr, 1);
}
static inline u8 *blkcipher_get_spot(u8 *start, unsigned int len)
{
if (offset_in_page(start + len) < len)
return (u8 *)((unsigned long)(start + len) & PAGE_MASK);
return start;
}
static inline unsigned int blkcipher_done_slow(struct crypto_blkcipher *tfm,
struct blkcipher_walk *walk,
unsigned int bsize)
{
u8 *addr;
unsigned int alignmask = crypto_blkcipher_alignmask(tfm);
addr = (u8 *)ALIGN((unsigned long)walk->buffer, alignmask + 1);
addr = blkcipher_get_spot(addr, bsize);
scatterwalk_copychunks(addr, &walk->out, bsize, 1);
return bsize;
}
static inline unsigned int blkcipher_done_fast(struct blkcipher_walk *walk,
unsigned int n)
{
n = walk->nbytes - n;
if (walk->flags & BLKCIPHER_WALK_COPY) {
blkcipher_map_dst(walk);
memcpy(walk->dst.virt.addr, walk->page, n);
blkcipher_unmap_dst(walk);
} else if (!(walk->flags & BLKCIPHER_WALK_PHYS)) {
blkcipher_unmap_src(walk);
if (walk->flags & BLKCIPHER_WALK_DIFF)
blkcipher_unmap_dst(walk);
}
scatterwalk_advance(&walk->in, n);
scatterwalk_advance(&walk->out, n);
return n;
}
int blkcipher_walk_done(struct blkcipher_desc *desc,
struct blkcipher_walk *walk, int err)
{
struct crypto_blkcipher *tfm = desc->tfm;
unsigned int nbytes = 0;
if (likely(err >= 0)) {
unsigned int bsize = crypto_blkcipher_blocksize(tfm);
unsigned int n;
if (likely(!(walk->flags & BLKCIPHER_WALK_SLOW)))
n = blkcipher_done_fast(walk, err);
else
n = blkcipher_done_slow(tfm, walk, bsize);
nbytes = walk->total - n;
err = 0;
}
scatterwalk_done(&walk->in, 0, nbytes);
scatterwalk_done(&walk->out, 1, nbytes);
walk->total = nbytes;
walk->nbytes = nbytes;
if (nbytes) {
crypto_yield(desc->flags);
return blkcipher_walk_next(desc, walk);
}
if (walk->iv != desc->info)
memcpy(desc->info, walk->iv, crypto_blkcipher_ivsize(tfm));
if (walk->buffer != walk->page)
kfree(walk->buffer);
if (walk->page)
free_page((unsigned long)walk->page);
return err;
}
EXPORT_SYMBOL_GPL(blkcipher_walk_done);
static inline int blkcipher_next_slow(struct blkcipher_desc *desc,
struct blkcipher_walk *walk,
unsigned int bsize,
unsigned int alignmask)
{
unsigned int n;
if (walk->buffer)
goto ok;
walk->buffer = walk->page;
if (walk->buffer)
goto ok;
n = bsize * 2 + (alignmask & ~(crypto_tfm_ctx_alignment() - 1));
walk->buffer = kmalloc(n, GFP_ATOMIC);
if (!walk->buffer)
return blkcipher_walk_done(desc, walk, -ENOMEM);
ok:
walk->dst.virt.addr = (u8 *)ALIGN((unsigned long)walk->buffer,
alignmask + 1);
walk->dst.virt.addr = blkcipher_get_spot(walk->dst.virt.addr, bsize);
walk->src.virt.addr = blkcipher_get_spot(walk->dst.virt.addr + bsize,
bsize);
scatterwalk_copychunks(walk->src.virt.addr, &walk->in, bsize, 0);
walk->nbytes = bsize;
walk->flags |= BLKCIPHER_WALK_SLOW;
return 0;
}
static inline int blkcipher_next_copy(struct blkcipher_walk *walk)
{
u8 *tmp = walk->page;
blkcipher_map_src(walk);
memcpy(tmp, walk->src.virt.addr, walk->nbytes);
blkcipher_unmap_src(walk);
walk->src.virt.addr = tmp;
walk->dst.virt.addr = tmp;
return 0;
}
static inline int blkcipher_next_fast(struct blkcipher_desc *desc,
struct blkcipher_walk *walk)
{
unsigned long diff;
walk->src.phys.page = scatterwalk_page(&walk->in);
walk->src.phys.offset = offset_in_page(walk->in.offset);
walk->dst.phys.page = scatterwalk_page(&walk->out);
walk->dst.phys.offset = offset_in_page(walk->out.offset);
if (walk->flags & BLKCIPHER_WALK_PHYS)
return 0;
diff = walk->src.phys.offset - walk->dst.phys.offset;
diff |= walk->src.virt.page - walk->dst.virt.page;
blkcipher_map_src(walk);
walk->dst.virt.addr = walk->src.virt.addr;
if (diff) {
walk->flags |= BLKCIPHER_WALK_DIFF;
blkcipher_map_dst(walk);
}
return 0;
}
static int blkcipher_walk_next(struct blkcipher_desc *desc,
struct blkcipher_walk *walk)
{
struct crypto_blkcipher *tfm = desc->tfm;
unsigned int alignmask = crypto_blkcipher_alignmask(tfm);
unsigned int bsize = crypto_blkcipher_blocksize(tfm);
unsigned int n;
int err;
n = walk->total;
if (unlikely(n < bsize)) {
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