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// SPDX-License-Identifier: GPL-2.0
/*
* This contains encryption functions for per-file encryption.
*
* Copyright (C) 2015, Google, Inc.
* Copyright (C) 2015, Motorola Mobility
*
* Written by Michael Halcrow, 2014.
*
* Filename encryption additions
* Uday Savagaonkar, 2014
* Encryption policy handling additions
* Ildar Muslukhov, 2014
* Add fscrypt_pullback_bio_page()
* Jaegeuk Kim, 2015.
*
* This has not yet undergone a rigorous security audit.
*
* The usage of AES-XTS should conform to recommendations in NIST
* Special Publication 800-38E and IEEE P1619/D16.
*/
#include <linux/pagemap.h>
#include <linux/module.h>
#include <linux/bio.h>
#include <linux/namei.h>
#include "fscrypt_private.h"
static void __fscrypt_decrypt_bio(struct bio *bio, bool done)
{
struct bio_vec *bv;
struct bvec_iter_all iter_all;
bio_for_each_segment_all(bv, bio, iter_all) {
struct page *page = bv->bv_page;
int ret = fscrypt_decrypt_pagecache_blocks(page, bv->bv_len,
bv->bv_offset);
if (ret)
SetPageError(page);
else if (done)
SetPageUptodate(page);
if (done)
unlock_page(page);
}
}
void fscrypt_decrypt_bio(struct bio *bio)
{
__fscrypt_decrypt_bio(bio, false);
}
EXPORT_SYMBOL(fscrypt_decrypt_bio);
static void completion_pages(struct work_struct *work)
{
struct fscrypt_ctx *ctx = container_of(work, struct fscrypt_ctx, work);
struct bio *bio = ctx->bio;
__fscrypt_decrypt_bio(bio, true);
fscrypt_release_ctx(ctx);
bio_put(bio);
}
void fscrypt_enqueue_decrypt_bio(struct fscrypt_ctx *ctx, struct bio *bio)
{
INIT_WORK(&ctx->work, completion_pages);
ctx->bio = bio;
fscrypt_enqueue_decrypt_work(&ctx->work);
}
EXPORT_SYMBOL(fscrypt_enqueue_decrypt_bio);
int fscrypt_zeroout_range(const struct inode *inode, pgoff_t lblk,
sector_t pblk, unsigned int len)
{
const unsigned int blockbits = inode->i_blkbits;
const unsigned int blocksize = 1 << blockbits;
struct page *ciphertext_page;
struct bio *bio;
int ret, err = 0;
ciphertext_page = fscrypt_alloc_bounce_page(GFP_NOWAIT);
if (!ciphertext_page)
return -ENOMEM;
while (len--) {
err = fscrypt_crypt_block(inode, FS_ENCRYPT, lblk,
ZERO_PAGE(0), ciphertext_page,
blocksize, 0, GFP_NOFS);
if (err)
goto errout;
bio = bio_alloc(GFP_NOWAIT, 1);
if (!bio) {
err = -ENOMEM;
goto errout;
}
bio_set_dev(bio, inode->i_sb->s_bdev);
bio->bi_iter.bi_sector = pblk << (blockbits - 9);
bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
ret = bio_add_page(bio, ciphertext_page, blocksize, 0);
if (WARN_ON(ret != blocksize)) {
/* should never happen! */
bio_put(bio);
err = -EIO;
goto errout;
}
err = submit_bio_wait(bio);
if (err == 0 && bio->bi_status)
err = -EIO;
bio_put(bio);
if (err)
goto errout;
lblk++;
pblk++;
}
err = 0;
errout:
fscrypt_free_bounce_page(ciphertext_page);
return err;
}
EXPORT_SYMBOL(fscrypt_zeroout_range);
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