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fscrypt: factor out bio specific functions
That way we can get rid of the direct dependency on CONFIG_BLOCK. Fixes: d475a50 ("ubifs: Add skeleton for fscrypto") Reported-by: Arnd Bergmann <[email protected]> Reported-by: Randy Dunlap <[email protected]> Reviewed-by: Eric Biggers <[email protected]> Reviewed-by: Christoph Hellwig <[email protected]> Reviewed-by: David Gstir <[email protected]> Signed-off-by: Richard Weinberger <[email protected]> Signed-off-by: Theodore Ts'o <[email protected]>
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -1,3 +1,4 @@ | ||
| obj-$(CONFIG_FS_ENCRYPTION) += fscrypto.o | ||
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| fscrypto-y := crypto.o fname.o policy.o keyinfo.o | ||
| fscrypto-$(CONFIG_BLOCK) += bio.o |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,145 @@ | ||
| /* | ||
| * 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. | ||
| */ | ||
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||
| #include <linux/pagemap.h> | ||
| #include <linux/module.h> | ||
| #include <linux/bio.h> | ||
| #include <linux/namei.h> | ||
| #include "fscrypt_private.h" | ||
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||
| /* | ||
| * Call fscrypt_decrypt_page on every single page, reusing the encryption | ||
| * context. | ||
| */ | ||
| static void completion_pages(struct work_struct *work) | ||
| { | ||
| struct fscrypt_ctx *ctx = | ||
| container_of(work, struct fscrypt_ctx, r.work); | ||
| struct bio *bio = ctx->r.bio; | ||
| struct bio_vec *bv; | ||
| int i; | ||
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| bio_for_each_segment_all(bv, bio, i) { | ||
| struct page *page = bv->bv_page; | ||
| int ret = fscrypt_decrypt_page(page->mapping->host, page, | ||
| PAGE_SIZE, 0, page->index); | ||
|
|
||
| if (ret) { | ||
| WARN_ON_ONCE(1); | ||
| SetPageError(page); | ||
| } else { | ||
| SetPageUptodate(page); | ||
| } | ||
| unlock_page(page); | ||
| } | ||
| fscrypt_release_ctx(ctx); | ||
| bio_put(bio); | ||
| } | ||
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| void fscrypt_decrypt_bio_pages(struct fscrypt_ctx *ctx, struct bio *bio) | ||
| { | ||
| INIT_WORK(&ctx->r.work, completion_pages); | ||
| ctx->r.bio = bio; | ||
| queue_work(fscrypt_read_workqueue, &ctx->r.work); | ||
| } | ||
| EXPORT_SYMBOL(fscrypt_decrypt_bio_pages); | ||
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| void fscrypt_pullback_bio_page(struct page **page, bool restore) | ||
| { | ||
| struct fscrypt_ctx *ctx; | ||
| struct page *bounce_page; | ||
|
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| /* The bounce data pages are unmapped. */ | ||
| if ((*page)->mapping) | ||
| return; | ||
|
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| /* The bounce data page is unmapped. */ | ||
| bounce_page = *page; | ||
| ctx = (struct fscrypt_ctx *)page_private(bounce_page); | ||
|
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| /* restore control page */ | ||
| *page = ctx->w.control_page; | ||
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| if (restore) | ||
| fscrypt_restore_control_page(bounce_page); | ||
| } | ||
| EXPORT_SYMBOL(fscrypt_pullback_bio_page); | ||
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| int fscrypt_zeroout_range(const struct inode *inode, pgoff_t lblk, | ||
| sector_t pblk, unsigned int len) | ||
| { | ||
| struct fscrypt_ctx *ctx; | ||
| struct page *ciphertext_page = NULL; | ||
| struct bio *bio; | ||
| 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); | ||
| if (IS_ERR(ctx)) | ||
| return PTR_ERR(ctx); | ||
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| ciphertext_page = fscrypt_alloc_bounce_page(ctx, GFP_NOWAIT); | ||
| if (IS_ERR(ciphertext_page)) { | ||
| err = PTR_ERR(ciphertext_page); | ||
| goto errout; | ||
| } | ||
|
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||
| while (len--) { | ||
| err = fscrypt_do_page_crypto(inode, FS_ENCRYPT, lblk, | ||
| ZERO_PAGE(0), ciphertext_page, | ||
| PAGE_SIZE, 0, GFP_NOFS); | ||
| if (err) | ||
| goto errout; | ||
|
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||
| bio = bio_alloc(GFP_NOWAIT, 1); | ||
| if (!bio) { | ||
| err = -ENOMEM; | ||
| goto errout; | ||
| } | ||
| bio->bi_bdev = inode->i_sb->s_bdev; | ||
| bio->bi_iter.bi_sector = | ||
| pblk << (inode->i_sb->s_blocksize_bits - 9); | ||
| bio_set_op_attrs(bio, REQ_OP_WRITE, 0); | ||
| ret = bio_add_page(bio, ciphertext_page, | ||
| inode->i_sb->s_blocksize, 0); | ||
| if (ret != inode->i_sb->s_blocksize) { | ||
| /* should never happen! */ | ||
| WARN_ON(1); | ||
| bio_put(bio); | ||
| err = -EIO; | ||
| goto errout; | ||
| } | ||
| err = submit_bio_wait(bio); | ||
| if ((err == 0) && bio->bi_error) | ||
| err = -EIO; | ||
| bio_put(bio); | ||
| if (err) | ||
| goto errout; | ||
| lblk++; | ||
| pblk++; | ||
| } | ||
| err = 0; | ||
| errout: | ||
| fscrypt_release_ctx(ctx); | ||
| return err; | ||
| } | ||
| EXPORT_SYMBOL(fscrypt_zeroout_range); |
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