1 // SPDX-License-Identifier: GPL-2.0
3 * This contains encryption functions for per-file encryption.
5 * Copyright (C) 2015, Google, Inc.
6 * Copyright (C) 2015, Motorola Mobility
8 * Written by Michael Halcrow, 2014.
10 * Filename encryption additions
11 * Uday Savagaonkar, 2014
12 * Encryption policy handling additions
13 * Ildar Muslukhov, 2014
14 * Add fscrypt_pullback_bio_page()
17 * This has not yet undergone a rigorous security audit.
19 * The usage of AES-XTS should conform to recommendations in NIST
20 * Special Publication 800-38E and IEEE P1619/D16.
23 #include <linux/pagemap.h>
24 #include <linux/module.h>
25 #include <linux/bio.h>
26 #include <linux/namei.h>
27 #include "fscrypt_private.h"
29 static void __fscrypt_decrypt_bio(struct bio
*bio
, bool done
)
32 struct bvec_iter_all iter_all
;
34 bio_for_each_segment_all(bv
, bio
, iter_all
) {
35 struct page
*page
= bv
->bv_page
;
36 int ret
= fscrypt_decrypt_pagecache_blocks(page
, bv
->bv_len
,
41 SetPageUptodate(page
);
47 void fscrypt_decrypt_bio(struct bio
*bio
)
49 __fscrypt_decrypt_bio(bio
, false);
51 EXPORT_SYMBOL(fscrypt_decrypt_bio
);
53 static void completion_pages(struct work_struct
*work
)
55 struct fscrypt_ctx
*ctx
= container_of(work
, struct fscrypt_ctx
, work
);
56 struct bio
*bio
= ctx
->bio
;
58 __fscrypt_decrypt_bio(bio
, true);
59 fscrypt_release_ctx(ctx
);
63 void fscrypt_enqueue_decrypt_bio(struct fscrypt_ctx
*ctx
, struct bio
*bio
)
65 INIT_WORK(&ctx
->work
, completion_pages
);
67 fscrypt_enqueue_decrypt_work(&ctx
->work
);
69 EXPORT_SYMBOL(fscrypt_enqueue_decrypt_bio
);
71 int fscrypt_zeroout_range(const struct inode
*inode
, pgoff_t lblk
,
72 sector_t pblk
, unsigned int len
)
74 const unsigned int blockbits
= inode
->i_blkbits
;
75 const unsigned int blocksize
= 1 << blockbits
;
76 struct page
*ciphertext_page
;
80 ciphertext_page
= fscrypt_alloc_bounce_page(GFP_NOWAIT
);
85 err
= fscrypt_crypt_block(inode
, FS_ENCRYPT
, lblk
,
86 ZERO_PAGE(0), ciphertext_page
,
87 blocksize
, 0, GFP_NOFS
);
91 bio
= bio_alloc(GFP_NOWAIT
, 1);
96 bio_set_dev(bio
, inode
->i_sb
->s_bdev
);
97 bio
->bi_iter
.bi_sector
= pblk
<< (blockbits
- 9);
98 bio_set_op_attrs(bio
, REQ_OP_WRITE
, 0);
99 ret
= bio_add_page(bio
, ciphertext_page
, blocksize
, 0);
100 if (WARN_ON(ret
!= blocksize
)) {
101 /* should never happen! */
106 err
= submit_bio_wait(bio
);
107 if (err
== 0 && bio
->bi_status
)
117 fscrypt_free_bounce_page(ciphertext_page
);
120 EXPORT_SYMBOL(fscrypt_zeroout_range
);