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ffceeefb33
In __fscrypt_decrypt_bio(), only decrypt the blocks that actually comprise the bio, rather than assuming blocksize == PAGE_SIZE and decrypting the entirety of every page used in the bio. This is in preparation for allowing encryption on ext4 filesystems with blocksize != PAGE_SIZE. This is based on work by Chandan Rajendra. Reviewed-by: Chandan Rajendra <chandan@linux.ibm.com> Signed-off-by: Eric Biggers <ebiggers@google.com>
120 lines
2.8 KiB
C
120 lines
2.8 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* This contains encryption functions for per-file encryption.
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*
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* Copyright (C) 2015, Google, Inc.
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* Copyright (C) 2015, Motorola Mobility
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*
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* Written by Michael Halcrow, 2014.
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*
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* Filename encryption additions
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* Uday Savagaonkar, 2014
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* Encryption policy handling additions
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* Ildar Muslukhov, 2014
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* Add fscrypt_pullback_bio_page()
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* Jaegeuk Kim, 2015.
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*
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* This has not yet undergone a rigorous security audit.
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*
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* The usage of AES-XTS should conform to recommendations in NIST
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* Special Publication 800-38E and IEEE P1619/D16.
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*/
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#include <linux/pagemap.h>
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#include <linux/module.h>
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#include <linux/bio.h>
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#include <linux/namei.h>
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#include "fscrypt_private.h"
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static void __fscrypt_decrypt_bio(struct bio *bio, bool done)
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{
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struct bio_vec *bv;
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struct bvec_iter_all iter_all;
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bio_for_each_segment_all(bv, bio, iter_all) {
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struct page *page = bv->bv_page;
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int ret = fscrypt_decrypt_pagecache_blocks(page, bv->bv_len,
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bv->bv_offset);
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if (ret)
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SetPageError(page);
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else if (done)
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SetPageUptodate(page);
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if (done)
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unlock_page(page);
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}
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}
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void fscrypt_decrypt_bio(struct bio *bio)
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{
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__fscrypt_decrypt_bio(bio, false);
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}
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EXPORT_SYMBOL(fscrypt_decrypt_bio);
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static void completion_pages(struct work_struct *work)
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{
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struct fscrypt_ctx *ctx = container_of(work, struct fscrypt_ctx, work);
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struct bio *bio = ctx->bio;
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__fscrypt_decrypt_bio(bio, true);
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fscrypt_release_ctx(ctx);
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bio_put(bio);
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}
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void fscrypt_enqueue_decrypt_bio(struct fscrypt_ctx *ctx, struct bio *bio)
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{
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INIT_WORK(&ctx->work, completion_pages);
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ctx->bio = bio;
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fscrypt_enqueue_decrypt_work(&ctx->work);
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}
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EXPORT_SYMBOL(fscrypt_enqueue_decrypt_bio);
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int fscrypt_zeroout_range(const struct inode *inode, pgoff_t lblk,
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sector_t pblk, unsigned int len)
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{
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const unsigned int blockbits = inode->i_blkbits;
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const unsigned int blocksize = 1 << blockbits;
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struct page *ciphertext_page;
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struct bio *bio;
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int ret, err = 0;
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ciphertext_page = fscrypt_alloc_bounce_page(GFP_NOWAIT);
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if (!ciphertext_page)
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return -ENOMEM;
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while (len--) {
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err = fscrypt_crypt_block(inode, FS_ENCRYPT, lblk,
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ZERO_PAGE(0), ciphertext_page,
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blocksize, 0, GFP_NOFS);
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if (err)
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goto errout;
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bio = bio_alloc(GFP_NOWAIT, 1);
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if (!bio) {
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err = -ENOMEM;
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goto errout;
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}
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bio_set_dev(bio, inode->i_sb->s_bdev);
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bio->bi_iter.bi_sector = pblk << (blockbits - 9);
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bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
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ret = bio_add_page(bio, ciphertext_page, blocksize, 0);
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if (WARN_ON(ret != blocksize)) {
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/* should never happen! */
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bio_put(bio);
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err = -EIO;
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goto errout;
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}
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err = submit_bio_wait(bio);
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if (err == 0 && bio->bi_status)
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err = -EIO;
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bio_put(bio);
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if (err)
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goto errout;
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lblk++;
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pblk++;
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}
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err = 0;
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errout:
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fscrypt_free_bounce_page(ciphertext_page);
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return err;
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}
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EXPORT_SYMBOL(fscrypt_zeroout_range);
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