fscrypt: factor out bio specific functions

That way we can get rid of the direct dependency on CONFIG_BLOCK.

Fixes: d475a507457b ("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>

diff --git a/fs/crypto/Kconfig b/fs/crypto/Kconfig
index f514978..08b46e6 100644 (file)
--- a/fs/crypto/Kconfig
+++ b/fs/crypto/Kconfig
@@ -1,6 +1,5 @@
 config FS_ENCRYPTION
        tristate "FS Encryption (Per-file encryption)"
-       depends on BLOCK
        select CRYPTO
        select CRYPTO_AES
        select CRYPTO_CBC

diff --git a/fs/crypto/Makefile b/fs/crypto/Makefile
index f17684c..9f6607f 100644 (file)
--- a/fs/crypto/Makefile
+++ b/fs/crypto/Makefile
@@ -1,3 +1,4 @@
 obj-$(CONFIG_FS_ENCRYPTION)    += fscrypto.o
 
 fscrypto-y := crypto.o fname.o policy.o keyinfo.o
+fscrypto-$(CONFIG_BLOCK) += bio.o

diff --git a/fs/crypto/bio.c b/fs/crypto/bio.c
new file mode 100644 (file)
index 0000000..a409a84
--- /dev/null
+++ b/fs/crypto/bio.c
@@ -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.
+ */
+
+#include <linux/pagemap.h>
+#include <linux/module.h>
+#include <linux/bio.h>
+#include <linux/namei.h>
+#include "fscrypt_private.h"
+
+/*
+ * 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;
+
+       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);
+}
+
+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);
+
+void fscrypt_pullback_bio_page(struct page **page, bool restore)
+{
+       struct fscrypt_ctx *ctx;
+       struct page *bounce_page;
+
+       /* The bounce data pages are unmapped. */
+       if ((*page)->mapping)
+               return;
+
+       /* The bounce data page is unmapped. */
+       bounce_page = *page;
+       ctx = (struct fscrypt_ctx *)page_private(bounce_page);
+
+       /* restore control page */
+       *page = ctx->w.control_page;
+
+       if (restore)
+               fscrypt_restore_control_page(bounce_page);
+}
+EXPORT_SYMBOL(fscrypt_pullback_bio_page);
+
+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;
+
+       BUG_ON(inode->i_sb->s_blocksize != PAGE_SIZE);
+
+       ctx = fscrypt_get_ctx(inode, GFP_NOFS);
+       if (IS_ERR(ctx))
+               return PTR_ERR(ctx);
+
+       ciphertext_page = fscrypt_alloc_bounce_page(ctx, GFP_NOWAIT);
+       if (IS_ERR(ciphertext_page)) {
+               err = PTR_ERR(ciphertext_page);
+               goto errout;
+       }
+
+       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;
+
+               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);

diff --git a/fs/crypto/crypto.c b/fs/crypto/crypto.c
index ac8e4f6..02a7a92 100644 (file)
--- a/fs/crypto/crypto.c
+++ b/fs/crypto/crypto.c
@@ -24,7 +24,6 @@
 #include <linux/module.h>
 #include <linux/scatterlist.h>
 #include <linux/ratelimit.h>
-#include <linux/bio.h>
 #include <linux/dcache.h>
 #include <linux/namei.h>
 #include "fscrypt_private.h"
@@ -44,7 +43,7 @@ static mempool_t *fscrypt_bounce_page_pool = NULL;
 static LIST_HEAD(fscrypt_free_ctxs);
 static DEFINE_SPINLOCK(fscrypt_ctx_lock);
 
-static struct workqueue_struct *fscrypt_read_workqueue;
+struct workqueue_struct *fscrypt_read_workqueue;
 static DEFINE_MUTEX(fscrypt_init_mutex);
 
 static struct kmem_cache *fscrypt_ctx_cachep;
@@ -141,16 +140,10 @@ static void page_crypt_complete(struct crypto_async_request *req, int res)
        complete(&ecr->completion);
 }
 
-typedef enum {
-       FS_DECRYPT = 0,
-       FS_ENCRYPT,
-} fscrypt_direction_t;
-
-static int do_page_crypto(const struct inode *inode,
-                       fscrypt_direction_t rw, u64 lblk_num,
-                       struct page *src_page, struct page *dest_page,
-                       unsigned int len, unsigned int offs,
-                       gfp_t gfp_flags)
+int fscrypt_do_page_crypto(const struct inode *inode, fscrypt_direction_t rw,
+                          u64 lblk_num, struct page *src_page,
+                          struct page *dest_page, unsigned int len,
+                          unsigned int offs, gfp_t gfp_flags)
 {
        struct {
                __le64 index;
@@ -205,7 +198,8 @@ static int do_page_crypto(const struct inode *inode,
        return 0;
 }
 
-static struct page *alloc_bounce_page(struct fscrypt_ctx *ctx, gfp_t gfp_flags)
+struct page *fscrypt_alloc_bounce_page(struct fscrypt_ctx *ctx,
+                                      gfp_t gfp_flags)
 {
        ctx->w.bounce_page = mempool_alloc(fscrypt_bounce_page_pool, gfp_flags);
        if (ctx->w.bounce_page == NULL)
@@ -260,9 +254,9 @@ struct page *fscrypt_encrypt_page(const struct inode *inode,
 
        if (inode->i_sb->s_cop->flags & FS_CFLG_OWN_PAGES) {
                /* with inplace-encryption we just encrypt the page */
-               err = do_page_crypto(inode, FS_ENCRYPT, lblk_num,
-                                       page, ciphertext_page,
-                                       len, offs, gfp_flags);
+               err = fscrypt_do_page_crypto(inode, FS_ENCRYPT, lblk_num, page,
+                                            ciphertext_page, len, offs,
+                                            gfp_flags);
                if (err)
                        return ERR_PTR(err);
 
@@ -276,14 +270,14 @@ struct page *fscrypt_encrypt_page(const struct inode *inode,
                return (struct page *)ctx;
 
        /* The encryption operation will require a bounce page. */
-       ciphertext_page = alloc_bounce_page(ctx, gfp_flags);
+       ciphertext_page = fscrypt_alloc_bounce_page(ctx, gfp_flags);
        if (IS_ERR(ciphertext_page))
                goto errout;
 
        ctx->w.control_page = page;
-       err = do_page_crypto(inode, FS_ENCRYPT, lblk_num,
-                                       page, ciphertext_page,
-                                       len, offs, gfp_flags);
+       err = fscrypt_do_page_crypto(inode, FS_ENCRYPT, lblk_num,
+                                    page, ciphertext_page, len, offs,
+                                    gfp_flags);
        if (err) {
                ciphertext_page = ERR_PTR(err);
                goto errout;
@@ -320,72 +314,11 @@ int fscrypt_decrypt_page(const struct inode *inode, struct page *page,
        if (!(inode->i_sb->s_cop->flags & FS_CFLG_OWN_PAGES))
                BUG_ON(!PageLocked(page));
 
-       return do_page_crypto(inode, FS_DECRYPT, lblk_num, page, page, len,
-                       offs, GFP_NOFS);
+       return fscrypt_do_page_crypto(inode, FS_DECRYPT, lblk_num, page, page,
+                                     len, offs, GFP_NOFS);
 }
 EXPORT_SYMBOL(fscrypt_decrypt_page);
 
-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;
-
-       BUG_ON(inode->i_sb->s_blocksize != PAGE_SIZE);
-
-       ctx = fscrypt_get_ctx(inode, GFP_NOFS);
-       if (IS_ERR(ctx))
-               return PTR_ERR(ctx);
-
-       ciphertext_page = alloc_bounce_page(ctx, GFP_NOWAIT);
-       if (IS_ERR(ciphertext_page)) {
-               err = PTR_ERR(ciphertext_page);
-               goto errout;
-       }
-
-       while (len--) {
-               err = do_page_crypto(inode, FS_ENCRYPT, lblk,
-                                       ZERO_PAGE(0), ciphertext_page,
-                                       PAGE_SIZE, 0, GFP_NOFS);
-               if (err)
-                       goto errout;
-
-               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);
-
 /*
  * Validate dentries for encrypted directories to make sure we aren't
  * potentially caching stale data after a key has been added or
@@ -442,64 +375,6 @@ const struct dentry_operations fscrypt_d_ops = {
 };
 EXPORT_SYMBOL(fscrypt_d_ops);
 
-/*
- * 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;
-
-       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);
-}
-
-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);
-
-void fscrypt_pullback_bio_page(struct page **page, bool restore)
-{
-       struct fscrypt_ctx *ctx;
-       struct page *bounce_page;
-
-       /* The bounce data pages are unmapped. */
-       if ((*page)->mapping)
-               return;
-
-       /* The bounce data page is unmapped. */
-       bounce_page = *page;
-       ctx = (struct fscrypt_ctx *)page_private(bounce_page);
-
-       /* restore control page */
-       *page = ctx->w.control_page;
-
-       if (restore)
-               fscrypt_restore_control_page(bounce_page);
-}
-EXPORT_SYMBOL(fscrypt_pullback_bio_page);
-
 void fscrypt_restore_control_page(struct page *page)
 {
        struct fscrypt_ctx *ctx;

diff --git a/fs/crypto/fscrypt_private.h b/fs/crypto/fscrypt_private.h
index aeab032..7bff7b4 100644 (file)
--- a/fs/crypto/fscrypt_private.h
+++ b/fs/crypto/fscrypt_private.h
@@ -71,6 +71,11 @@ struct fscrypt_info {
        u8 ci_master_key[FS_KEY_DESCRIPTOR_SIZE];
 };
 
+typedef enum {
+       FS_DECRYPT = 0,
+       FS_ENCRYPT,
+} fscrypt_direction_t;
+
 #define FS_CTX_REQUIRES_FREE_ENCRYPT_FL                0x00000001
 #define FS_CTX_HAS_BOUNCE_BUFFER_FL            0x00000002
 
@@ -85,7 +90,16 @@ struct fscrypt_completion_result {
 
 
 /* crypto.c */
-int fscrypt_initialize(unsigned int cop_flags);
+extern int fscrypt_initialize(unsigned int cop_flags);
+extern struct workqueue_struct *fscrypt_read_workqueue;
+extern int fscrypt_do_page_crypto(const struct inode *inode,
+                                 fscrypt_direction_t rw, u64 lblk_num,
+                                 struct page *src_page,
+                                 struct page *dest_page,
+                                 unsigned int len, unsigned int offs,
+                                 gfp_t gfp_flags);
+extern struct page *fscrypt_alloc_bounce_page(struct fscrypt_ctx *ctx,
+                                             gfp_t gfp_flags);
 
 /* keyinfo.c */
 extern int fscrypt_get_crypt_info(struct inode *);

diff --git a/include/linux/fscrypto.h b/include/linux/fscrypto.h
index c074b67..2a28157 100644 (file)
--- a/include/linux/fscrypto.h
+++ b/include/linux/fscrypto.h
@@ -174,11 +174,8 @@ extern struct page *fscrypt_encrypt_page(const struct inode *, struct page *,
                                                u64, gfp_t);
 extern int fscrypt_decrypt_page(const struct inode *, struct page *, unsigned int,
                                unsigned int, u64);
-extern void fscrypt_decrypt_bio_pages(struct fscrypt_ctx *, struct bio *);
-extern void fscrypt_pullback_bio_page(struct page **, bool);
 extern void fscrypt_restore_control_page(struct page *);
-extern int fscrypt_zeroout_range(const struct inode *, pgoff_t, sector_t,
-                                               unsigned int);
+
 /* policy.c */
 extern int fscrypt_ioctl_set_policy(struct file *, const void __user *);
 extern int fscrypt_ioctl_get_policy(struct file *, void __user *);
@@ -201,6 +198,12 @@ extern int fscrypt_fname_disk_to_usr(struct inode *, u32, u32,
                        const struct fscrypt_str *, struct fscrypt_str *);
 extern int fscrypt_fname_usr_to_disk(struct inode *, const struct qstr *,
                        struct fscrypt_str *);
+
+/* bio.c */
+extern void fscrypt_decrypt_bio_pages(struct fscrypt_ctx *, struct bio *);
+extern void fscrypt_pullback_bio_page(struct page **, bool);
+extern int fscrypt_zeroout_range(const struct inode *, pgoff_t, sector_t,
+                                unsigned int);
 #endif
 
 /* crypto.c */