fscrypt: factor out bio specific functions
That way we can get rid of the direct dependency on CONFIG_BLOCK.
Fixes: d475a50745 ("ubifs: Add skeleton for fscrypto")
Reported-by: Arnd Bergmann <arnd@arndb.de>
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Gstir <david@sigma-star.at>
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
This commit is contained in:
Richard Weinberger
Theodore Ts'o
parent
efee590e4a
commit
58ae74683a
@ -1,6 +1,5 @@
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config FS_ENCRYPTION
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tristate "FS Encryption (Per-file encryption)"
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depends on BLOCK
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select CRYPTO
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select CRYPTO_AES
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select CRYPTO_CBC
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@ -1,3 +1,4 @@
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obj-$(CONFIG_FS_ENCRYPTION) += fscrypto.o
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fscrypto-y := crypto.o fname.o policy.o keyinfo.o
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fscrypto-$(CONFIG_BLOCK) += bio.o
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145
fs/crypto/bio.c
Normal file
145
fs/crypto/bio.c
Normal file
@ -0,0 +1,145 @@
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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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/*
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* Call fscrypt_decrypt_page on every single page, reusing the encryption
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* context.
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*/
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static void completion_pages(struct work_struct *work)
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{
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struct fscrypt_ctx *ctx =
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container_of(work, struct fscrypt_ctx, r.work);
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struct bio *bio = ctx->r.bio;
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struct bio_vec *bv;
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int i;
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bio_for_each_segment_all(bv, bio, i) {
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struct page *page = bv->bv_page;
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int ret = fscrypt_decrypt_page(page->mapping->host, page,
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PAGE_SIZE, 0, page->index);
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if (ret) {
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WARN_ON_ONCE(1);
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SetPageError(page);
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} else {
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SetPageUptodate(page);
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}
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unlock_page(page);
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}
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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_decrypt_bio_pages(struct fscrypt_ctx *ctx, struct bio *bio)
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{
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INIT_WORK(&ctx->r.work, completion_pages);
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ctx->r.bio = bio;
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queue_work(fscrypt_read_workqueue, &ctx->r.work);
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}
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EXPORT_SYMBOL(fscrypt_decrypt_bio_pages);
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void fscrypt_pullback_bio_page(struct page **page, bool restore)
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{
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struct fscrypt_ctx *ctx;
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struct page *bounce_page;
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/* The bounce data pages are unmapped. */
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if ((*page)->mapping)
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return;
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/* The bounce data page is unmapped. */
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bounce_page = *page;
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ctx = (struct fscrypt_ctx *)page_private(bounce_page);
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/* restore control page */
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*page = ctx->w.control_page;
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if (restore)
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fscrypt_restore_control_page(bounce_page);
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}
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EXPORT_SYMBOL(fscrypt_pullback_bio_page);
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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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struct fscrypt_ctx *ctx;
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struct page *ciphertext_page = NULL;
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struct bio *bio;
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int ret, err = 0;
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BUG_ON(inode->i_sb->s_blocksize != PAGE_SIZE);
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ctx = fscrypt_get_ctx(inode, GFP_NOFS);
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if (IS_ERR(ctx))
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return PTR_ERR(ctx);
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ciphertext_page = fscrypt_alloc_bounce_page(ctx, GFP_NOWAIT);
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if (IS_ERR(ciphertext_page)) {
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err = PTR_ERR(ciphertext_page);
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goto errout;
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}
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while (len--) {
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err = fscrypt_do_page_crypto(inode, FS_ENCRYPT, lblk,
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ZERO_PAGE(0), ciphertext_page,
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PAGE_SIZE, 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->bi_bdev = inode->i_sb->s_bdev;
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bio->bi_iter.bi_sector =
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pblk << (inode->i_sb->s_blocksize_bits - 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,
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inode->i_sb->s_blocksize, 0);
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if (ret != inode->i_sb->s_blocksize) {
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/* should never happen! */
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WARN_ON(1);
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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_error)
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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_release_ctx(ctx);
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return err;
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}
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EXPORT_SYMBOL(fscrypt_zeroout_range);
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@ -24,7 +24,6 @@
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#include <linux/module.h>
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#include <linux/scatterlist.h>
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#include <linux/ratelimit.h>
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#include <linux/bio.h>
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#include <linux/dcache.h>
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#include <linux/namei.h>
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#include "fscrypt_private.h"
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@ -44,7 +43,7 @@ static mempool_t *fscrypt_bounce_page_pool = NULL;
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static LIST_HEAD(fscrypt_free_ctxs);
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static DEFINE_SPINLOCK(fscrypt_ctx_lock);
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static struct workqueue_struct *fscrypt_read_workqueue;
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struct workqueue_struct *fscrypt_read_workqueue;
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static DEFINE_MUTEX(fscrypt_init_mutex);
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static struct kmem_cache *fscrypt_ctx_cachep;
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@ -141,16 +140,10 @@ static void page_crypt_complete(struct crypto_async_request *req, int res)
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complete(&ecr->completion);
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}
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typedef enum {
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FS_DECRYPT = 0,
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FS_ENCRYPT,
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} fscrypt_direction_t;
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static int do_page_crypto(const struct inode *inode,
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fscrypt_direction_t rw, u64 lblk_num,
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struct page *src_page, struct page *dest_page,
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unsigned int len, unsigned int offs,
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gfp_t gfp_flags)
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int fscrypt_do_page_crypto(const struct inode *inode, fscrypt_direction_t rw,
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u64 lblk_num, struct page *src_page,
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struct page *dest_page, unsigned int len,
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unsigned int offs, gfp_t gfp_flags)
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{
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struct {
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__le64 index;
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@ -205,7 +198,8 @@ static int do_page_crypto(const struct inode *inode,
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return 0;
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}
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static struct page *alloc_bounce_page(struct fscrypt_ctx *ctx, gfp_t gfp_flags)
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struct page *fscrypt_alloc_bounce_page(struct fscrypt_ctx *ctx,
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gfp_t gfp_flags)
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{
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ctx->w.bounce_page = mempool_alloc(fscrypt_bounce_page_pool, gfp_flags);
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if (ctx->w.bounce_page == NULL)
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@ -260,9 +254,9 @@ struct page *fscrypt_encrypt_page(const struct inode *inode,
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if (inode->i_sb->s_cop->flags & FS_CFLG_OWN_PAGES) {
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/* with inplace-encryption we just encrypt the page */
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err = do_page_crypto(inode, FS_ENCRYPT, lblk_num,
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page, ciphertext_page,
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len, offs, gfp_flags);
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err = fscrypt_do_page_crypto(inode, FS_ENCRYPT, lblk_num, page,
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ciphertext_page, len, offs,
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gfp_flags);
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if (err)
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return ERR_PTR(err);
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@ -276,14 +270,14 @@ struct page *fscrypt_encrypt_page(const struct inode *inode,
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return (struct page *)ctx;
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/* The encryption operation will require a bounce page. */
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ciphertext_page = alloc_bounce_page(ctx, gfp_flags);
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ciphertext_page = fscrypt_alloc_bounce_page(ctx, gfp_flags);
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if (IS_ERR(ciphertext_page))
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goto errout;
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ctx->w.control_page = page;
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err = do_page_crypto(inode, FS_ENCRYPT, lblk_num,
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page, ciphertext_page,
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len, offs, gfp_flags);
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err = fscrypt_do_page_crypto(inode, FS_ENCRYPT, lblk_num,
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page, ciphertext_page, len, offs,
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gfp_flags);
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if (err) {
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ciphertext_page = ERR_PTR(err);
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goto errout;
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@ -320,72 +314,11 @@ int fscrypt_decrypt_page(const struct inode *inode, struct page *page,
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if (!(inode->i_sb->s_cop->flags & FS_CFLG_OWN_PAGES))
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BUG_ON(!PageLocked(page));
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return do_page_crypto(inode, FS_DECRYPT, lblk_num, page, page, len,
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offs, GFP_NOFS);
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return fscrypt_do_page_crypto(inode, FS_DECRYPT, lblk_num, page, page,
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len, offs, GFP_NOFS);
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}
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EXPORT_SYMBOL(fscrypt_decrypt_page);
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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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struct fscrypt_ctx *ctx;
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struct page *ciphertext_page = NULL;
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struct bio *bio;
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int ret, err = 0;
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BUG_ON(inode->i_sb->s_blocksize != PAGE_SIZE);
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ctx = fscrypt_get_ctx(inode, GFP_NOFS);
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if (IS_ERR(ctx))
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return PTR_ERR(ctx);
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ciphertext_page = alloc_bounce_page(ctx, GFP_NOWAIT);
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if (IS_ERR(ciphertext_page)) {
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err = PTR_ERR(ciphertext_page);
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goto errout;
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}
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while (len--) {
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err = do_page_crypto(inode, FS_ENCRYPT, lblk,
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ZERO_PAGE(0), ciphertext_page,
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PAGE_SIZE, 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->bi_bdev = inode->i_sb->s_bdev;
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bio->bi_iter.bi_sector =
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pblk << (inode->i_sb->s_blocksize_bits - 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,
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inode->i_sb->s_blocksize, 0);
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if (ret != inode->i_sb->s_blocksize) {
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/* should never happen! */
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WARN_ON(1);
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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_error)
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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_release_ctx(ctx);
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return err;
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}
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EXPORT_SYMBOL(fscrypt_zeroout_range);
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/*
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* Validate dentries for encrypted directories to make sure we aren't
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* potentially caching stale data after a key has been added or
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@ -442,64 +375,6 @@ const struct dentry_operations fscrypt_d_ops = {
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};
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EXPORT_SYMBOL(fscrypt_d_ops);
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/*
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* Call fscrypt_decrypt_page on every single page, reusing the encryption
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* context.
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*/
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static void completion_pages(struct work_struct *work)
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{
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struct fscrypt_ctx *ctx =
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container_of(work, struct fscrypt_ctx, r.work);
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struct bio *bio = ctx->r.bio;
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struct bio_vec *bv;
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int i;
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bio_for_each_segment_all(bv, bio, i) {
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struct page *page = bv->bv_page;
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int ret = fscrypt_decrypt_page(page->mapping->host, page,
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PAGE_SIZE, 0, page->index);
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if (ret) {
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WARN_ON_ONCE(1);
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SetPageError(page);
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} else {
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SetPageUptodate(page);
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}
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unlock_page(page);
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}
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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_decrypt_bio_pages(struct fscrypt_ctx *ctx, struct bio *bio)
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{
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INIT_WORK(&ctx->r.work, completion_pages);
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ctx->r.bio = bio;
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queue_work(fscrypt_read_workqueue, &ctx->r.work);
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}
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EXPORT_SYMBOL(fscrypt_decrypt_bio_pages);
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void fscrypt_pullback_bio_page(struct page **page, bool restore)
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{
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struct fscrypt_ctx *ctx;
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struct page *bounce_page;
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/* The bounce data pages are unmapped. */
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if ((*page)->mapping)
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return;
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/* The bounce data page is unmapped. */
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bounce_page = *page;
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ctx = (struct fscrypt_ctx *)page_private(bounce_page);
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/* restore control page */
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*page = ctx->w.control_page;
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if (restore)
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fscrypt_restore_control_page(bounce_page);
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}
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EXPORT_SYMBOL(fscrypt_pullback_bio_page);
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void fscrypt_restore_control_page(struct page *page)
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{
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struct fscrypt_ctx *ctx;
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@ -71,6 +71,11 @@ struct fscrypt_info {
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u8 ci_master_key[FS_KEY_DESCRIPTOR_SIZE];
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};
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typedef enum {
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FS_DECRYPT = 0,
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FS_ENCRYPT,
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} fscrypt_direction_t;
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#define FS_CTX_REQUIRES_FREE_ENCRYPT_FL 0x00000001
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#define FS_CTX_HAS_BOUNCE_BUFFER_FL 0x00000002
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@ -85,7 +90,16 @@ struct fscrypt_completion_result {
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/* crypto.c */
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int fscrypt_initialize(unsigned int cop_flags);
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extern int fscrypt_initialize(unsigned int cop_flags);
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extern struct workqueue_struct *fscrypt_read_workqueue;
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extern int fscrypt_do_page_crypto(const struct inode *inode,
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fscrypt_direction_t rw, u64 lblk_num,
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struct page *src_page,
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struct page *dest_page,
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unsigned int len, unsigned int offs,
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gfp_t gfp_flags);
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extern struct page *fscrypt_alloc_bounce_page(struct fscrypt_ctx *ctx,
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gfp_t gfp_flags);
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/* keyinfo.c */
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extern int fscrypt_get_crypt_info(struct inode *);
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@ -174,11 +174,8 @@ extern struct page *fscrypt_encrypt_page(const struct inode *, struct page *,
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u64, gfp_t);
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extern int fscrypt_decrypt_page(const struct inode *, struct page *, unsigned int,
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unsigned int, u64);
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extern void fscrypt_decrypt_bio_pages(struct fscrypt_ctx *, struct bio *);
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extern void fscrypt_pullback_bio_page(struct page **, bool);
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extern void fscrypt_restore_control_page(struct page *);
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extern int fscrypt_zeroout_range(const struct inode *, pgoff_t, sector_t,
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unsigned int);
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/* policy.c */
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extern int fscrypt_ioctl_set_policy(struct file *, const void __user *);
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extern int fscrypt_ioctl_get_policy(struct file *, void __user *);
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@ -201,6 +198,12 @@ extern int fscrypt_fname_disk_to_usr(struct inode *, u32, u32,
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const struct fscrypt_str *, struct fscrypt_str *);
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extern int fscrypt_fname_usr_to_disk(struct inode *, const struct qstr *,
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struct fscrypt_str *);
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/* bio.c */
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extern void fscrypt_decrypt_bio_pages(struct fscrypt_ctx *, struct bio *);
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extern void fscrypt_pullback_bio_page(struct page **, bool);
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extern int fscrypt_zeroout_range(const struct inode *, pgoff_t, sector_t,
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unsigned int);
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#endif
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/* crypto.c */
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