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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * This contains encryption functions for per-file encryption.
4 *
5 * Copyright (C) 2015, Google, Inc.
6 * Copyright (C) 2015, Motorola Mobility
7 *
8 * Written by Michael Halcrow, 2014.
9 *
10 * Filename encryption additions
11 * Uday Savagaonkar, 2014
12 * Encryption policy handling additions
13 * Ildar Muslukhov, 2014
14 * Add fscrypt_pullback_bio_page()
15 * Jaegeuk Kim, 2015.
16 *
17 * This has not yet undergone a rigorous security audit.
18 *
19 * The usage of AES-XTS should conform to recommendations in NIST
20 * Special Publication 800-38E and IEEE P1619/D16.
21 */
22
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"
28
29/*
30 * Call fscrypt_decrypt_page on every single page, reusing the encryption
31 * context.
32 */
33static void completion_pages(struct work_struct *work)
34{
35 struct fscrypt_ctx *ctx =
36 container_of(work, struct fscrypt_ctx, r.work);
37 struct bio *bio = ctx->r.bio;
38 struct bio_vec *bv;
39 int i;
40
41 bio_for_each_segment_all(bv, bio, i) {
42 struct page *page = bv->bv_page;
43 int ret = fscrypt_decrypt_page(page->mapping->host, page,
44 PAGE_SIZE, 0, page->index);
45
46 if (ret) {
47 WARN_ON_ONCE(1);
48 SetPageError(page);
49 } else {
50 SetPageUptodate(page);
51 }
52 unlock_page(page);
53 }
54 fscrypt_release_ctx(ctx);
55 bio_put(bio);
56}
57
58void fscrypt_decrypt_bio_pages(struct fscrypt_ctx *ctx, struct bio *bio)
59{
60 INIT_WORK(&ctx->r.work, completion_pages);
61 ctx->r.bio = bio;
62 queue_work(fscrypt_read_workqueue, &ctx->r.work);
63}
64EXPORT_SYMBOL(fscrypt_decrypt_bio_pages);
65
66void fscrypt_pullback_bio_page(struct page **page, bool restore)
67{
68 struct fscrypt_ctx *ctx;
69 struct page *bounce_page;
70
71 /* The bounce data pages are unmapped. */
72 if ((*page)->mapping)
73 return;
74
75 /* The bounce data page is unmapped. */
76 bounce_page = *page;
77 ctx = (struct fscrypt_ctx *)page_private(bounce_page);
78
79 /* restore control page */
80 *page = ctx->w.control_page;
81
82 if (restore)
83 fscrypt_restore_control_page(bounce_page);
84}
85EXPORT_SYMBOL(fscrypt_pullback_bio_page);
86
87int fscrypt_zeroout_range(const struct inode *inode, pgoff_t lblk,
88 sector_t pblk, unsigned int len)
89{
90 struct fscrypt_ctx *ctx;
91 struct page *ciphertext_page = NULL;
92 struct bio *bio;
93 int ret, err = 0;
94
95 BUG_ON(inode->i_sb->s_blocksize != PAGE_SIZE);
96
97 ctx = fscrypt_get_ctx(inode, GFP_NOFS);
98 if (IS_ERR(ctx))
99 return PTR_ERR(ctx);
100
101 ciphertext_page = fscrypt_alloc_bounce_page(ctx, GFP_NOWAIT);
102 if (IS_ERR(ciphertext_page)) {
103 err = PTR_ERR(ciphertext_page);
104 goto errout;
105 }
106
107 while (len--) {
108 err = fscrypt_do_page_crypto(inode, FS_ENCRYPT, lblk,
109 ZERO_PAGE(0), ciphertext_page,
110 PAGE_SIZE, 0, GFP_NOFS);
111 if (err)
112 goto errout;
113
114 bio = bio_alloc(GFP_NOWAIT, 1);
115 if (!bio) {
116 err = -ENOMEM;
117 goto errout;
118 }
119 bio_set_dev(bio, inode->i_sb->s_bdev);
120 bio->bi_iter.bi_sector =
121 pblk << (inode->i_sb->s_blocksize_bits - 9);
122 bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
123 ret = bio_add_page(bio, ciphertext_page,
124 inode->i_sb->s_blocksize, 0);
125 if (ret != inode->i_sb->s_blocksize) {
126 /* should never happen! */
127 WARN_ON(1);
128 bio_put(bio);
129 err = -EIO;
130 goto errout;
131 }
132 err = submit_bio_wait(bio);
133 if (err == 0 && bio->bi_status)
134 err = -EIO;
135 bio_put(bio);
136 if (err)
137 goto errout;
138 lblk++;
139 pblk++;
140 }
141 err = 0;
142errout:
143 fscrypt_release_ctx(ctx);
144 return err;
145}
146EXPORT_SYMBOL(fscrypt_zeroout_range);
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * This contains encryption functions for per-file encryption.
4 *
5 * Copyright (C) 2015, Google, Inc.
6 * Copyright (C) 2015, Motorola Mobility
7 *
8 * Written by Michael Halcrow, 2014.
9 *
10 * Filename encryption additions
11 * Uday Savagaonkar, 2014
12 * Encryption policy handling additions
13 * Ildar Muslukhov, 2014
14 * Add fscrypt_pullback_bio_page()
15 * Jaegeuk Kim, 2015.
16 *
17 * This has not yet undergone a rigorous security audit.
18 *
19 * The usage of AES-XTS should conform to recommendations in NIST
20 * Special Publication 800-38E and IEEE P1619/D16.
21 */
22
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"
28
29static void __fscrypt_decrypt_bio(struct bio *bio, bool done)
30{
31 struct bio_vec *bv;
32 struct bvec_iter_all iter_all;
33
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,
37 bv->bv_offset);
38 if (ret)
39 SetPageError(page);
40 else if (done)
41 SetPageUptodate(page);
42 if (done)
43 unlock_page(page);
44 }
45}
46
47void fscrypt_decrypt_bio(struct bio *bio)
48{
49 __fscrypt_decrypt_bio(bio, false);
50}
51EXPORT_SYMBOL(fscrypt_decrypt_bio);
52
53static void completion_pages(struct work_struct *work)
54{
55 struct fscrypt_ctx *ctx = container_of(work, struct fscrypt_ctx, work);
56 struct bio *bio = ctx->bio;
57
58 __fscrypt_decrypt_bio(bio, true);
59 fscrypt_release_ctx(ctx);
60 bio_put(bio);
61}
62
63void fscrypt_enqueue_decrypt_bio(struct fscrypt_ctx *ctx, struct bio *bio)
64{
65 INIT_WORK(&ctx->work, completion_pages);
66 ctx->bio = bio;
67 fscrypt_enqueue_decrypt_work(&ctx->work);
68}
69EXPORT_SYMBOL(fscrypt_enqueue_decrypt_bio);
70
71int fscrypt_zeroout_range(const struct inode *inode, pgoff_t lblk,
72 sector_t pblk, unsigned int len)
73{
74 const unsigned int blockbits = inode->i_blkbits;
75 const unsigned int blocksize = 1 << blockbits;
76 struct page *ciphertext_page;
77 struct bio *bio;
78 int ret, err = 0;
79
80 ciphertext_page = fscrypt_alloc_bounce_page(GFP_NOWAIT);
81 if (!ciphertext_page)
82 return -ENOMEM;
83
84 while (len--) {
85 err = fscrypt_crypt_block(inode, FS_ENCRYPT, lblk,
86 ZERO_PAGE(0), ciphertext_page,
87 blocksize, 0, GFP_NOFS);
88 if (err)
89 goto errout;
90
91 bio = bio_alloc(GFP_NOWAIT, 1);
92 if (!bio) {
93 err = -ENOMEM;
94 goto errout;
95 }
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! */
102 bio_put(bio);
103 err = -EIO;
104 goto errout;
105 }
106 err = submit_bio_wait(bio);
107 if (err == 0 && bio->bi_status)
108 err = -EIO;
109 bio_put(bio);
110 if (err)
111 goto errout;
112 lblk++;
113 pblk++;
114 }
115 err = 0;
116errout:
117 fscrypt_free_bounce_page(ciphertext_page);
118 return err;
119}
120EXPORT_SYMBOL(fscrypt_zeroout_range);