Merge branch 'fscrypt' into d

18 files changed, 263 insertions, 301 deletions

diff --git a/fs/crypto/Kconfig b/fs/crypto/Kconfig
index f514978f6688..08b46e6e3995 100644
--- 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 f17684c48739..9f6607f17b53 100644
--- 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
index 000000000000..a409a84f1bca
--- /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 ac8e4f6a3773..02a7a9286449 100644
--- 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/fname.c b/fs/crypto/fname.c
index 56ad9d195f18..13052b85c393 100644
--- a/fs/crypto/fname.c
+++ b/fs/crypto/fname.c
@@ -332,7 +332,7 @@ int fscrypt_fname_usr_to_disk(struct inode *inode,
 	 * in a directory. Consequently, a user space name cannot be mapped to
 	 * a disk-space name
 	 */
-	return -EACCES;
+	return -ENOKEY;
 }
 EXPORT_SYMBOL(fscrypt_fname_usr_to_disk);
 
@@ -367,7 +367,7 @@ int fscrypt_setup_filename(struct inode *dir, const struct qstr *iname,
 		return 0;
 	}
 	if (!lookup)
-		return -EACCES;
+		return -ENOKEY;
 
 	/*
 	 * We don't have the key and we are doing a lookup; decode the
diff --git a/fs/crypto/fscrypt_private.h b/fs/crypto/fscrypt_private.h
index aeab032d7d35..7bff7b4c7498 100644
--- 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/fs/crypto/keyinfo.c b/fs/crypto/keyinfo.c
index 95cd4c3b06c3..eeb6fd67ea17 100644
--- a/fs/crypto/keyinfo.c
+++ b/fs/crypto/keyinfo.c
@@ -77,26 +77,22 @@ out:
 
 static int validate_user_key(struct fscrypt_info *crypt_info,
 			struct fscrypt_context *ctx, u8 *raw_key,
-			u8 *prefix, int prefix_size)
+			const char *prefix)
 {
-	u8 *full_key_descriptor;
+	char *description;
 	struct key *keyring_key;
 	struct fscrypt_key *master_key;
 	const struct user_key_payload *ukp;
-	int full_key_len = prefix_size + (FS_KEY_DESCRIPTOR_SIZE * 2) + 1;
 	int res;
 
-	full_key_descriptor = kmalloc(full_key_len, GFP_NOFS);
-	if (!full_key_descriptor)
+	description = kasprintf(GFP_NOFS, "%s%*phN", prefix,
+				FS_KEY_DESCRIPTOR_SIZE,
+				ctx->master_key_descriptor);
+	if (!description)
 		return -ENOMEM;
 
-	memcpy(full_key_descriptor, prefix, prefix_size);
-	sprintf(full_key_descriptor + prefix_size,
-			"%*phN", FS_KEY_DESCRIPTOR_SIZE,
-			ctx->master_key_descriptor);
-	full_key_descriptor[full_key_len - 1] = '\0';
-	keyring_key = request_key(&key_type_logon, full_key_descriptor, NULL);
-	kfree(full_key_descriptor);
+	keyring_key = request_key(&key_type_logon, description, NULL);
+	kfree(description);
 	if (IS_ERR(keyring_key))
 		return PTR_ERR(keyring_key);
 
@@ -206,12 +202,16 @@ retry:
 
 	res = inode->i_sb->s_cop->get_context(inode, &ctx, sizeof(ctx));
 	if (res < 0) {
-		if (!fscrypt_dummy_context_enabled(inode))
+		if (!fscrypt_dummy_context_enabled(inode) ||
+		    inode->i_sb->s_cop->is_encrypted(inode))
 			return res;
+		/* Fake up a context for an unencrypted directory */
+		memset(&ctx, 0, sizeof(ctx));
 		ctx.format = FS_ENCRYPTION_CONTEXT_FORMAT_V1;
 		ctx.contents_encryption_mode = FS_ENCRYPTION_MODE_AES_256_XTS;
 		ctx.filenames_encryption_mode = FS_ENCRYPTION_MODE_AES_256_CTS;
-		ctx.flags = 0;
+		memset(ctx.master_key_descriptor, 0x42, FS_KEY_DESCRIPTOR_SIZE);
+		res = sizeof(ctx);
 	} else if (res != sizeof(ctx)) {
 		return -EINVAL;
 	}
@@ -247,21 +247,10 @@ retry:
 	if (!raw_key)
 		goto out;
 
-	if (fscrypt_dummy_context_enabled(inode)) {
-		memset(raw_key, 0x42, keysize/2);
-		memset(raw_key+keysize/2, 0x24, keysize - (keysize/2));
-		goto got_key;
-	}
-
-	res = validate_user_key(crypt_info, &ctx, raw_key,
-			FS_KEY_DESC_PREFIX, FS_KEY_DESC_PREFIX_SIZE);
+	res = validate_user_key(crypt_info, &ctx, raw_key, FS_KEY_DESC_PREFIX);
 	if (res && inode->i_sb->s_cop->key_prefix) {
-		u8 *prefix = NULL;
-		int prefix_size, res2;
-
-		prefix_size = inode->i_sb->s_cop->key_prefix(inode, &prefix);
-		res2 = validate_user_key(crypt_info, &ctx, raw_key,
-							prefix, prefix_size);
+		int res2 = validate_user_key(crypt_info, &ctx, raw_key,
+					     inode->i_sb->s_cop->key_prefix);
 		if (res2) {
 			if (res2 == -ENOKEY)
 				res = -ENOKEY;
@@ -270,7 +259,6 @@ retry:
 	} else if (res) {
 		goto out;
 	}
-got_key:
 	ctfm = crypto_alloc_skcipher(cipher_str, 0, 0);
 	if (!ctfm || IS_ERR(ctfm)) {
 		res = ctfm ? PTR_ERR(ctfm) : -ENOMEM;
diff --git a/fs/crypto/policy.c b/fs/crypto/policy.c
index d6cd7ea4851d..14b76da71269 100644
--- a/fs/crypto/policy.c
+++ b/fs/crypto/policy.c
@@ -13,37 +13,20 @@
 #include <linux/mount.h>
 #include "fscrypt_private.h"
 
-static int inode_has_encryption_context(struct inode *inode)
-{
-	if (!inode->i_sb->s_cop->get_context)
-		return 0;
-	return (inode->i_sb->s_cop->get_context(inode, NULL, 0L) > 0);
-}
-
 /*
- * check whether the policy is consistent with the encryption context
- * for the inode
+ * check whether an encryption policy is consistent with an encryption context
  */
-static int is_encryption_context_consistent_with_policy(struct inode *inode,
+static bool is_encryption_context_consistent_with_policy(
+				const struct fscrypt_context *ctx,
 				const struct fscrypt_policy *policy)
 {
-	struct fscrypt_context ctx;
-	int res;
-
-	if (!inode->i_sb->s_cop->get_context)
-		return 0;
-
-	res = inode->i_sb->s_cop->get_context(inode, &ctx, sizeof(ctx));
-	if (res != sizeof(ctx))
-		return 0;
-
-	return (memcmp(ctx.master_key_descriptor, policy->master_key_descriptor,
-			FS_KEY_DESCRIPTOR_SIZE) == 0 &&
-			(ctx.flags == policy->flags) &&
-			(ctx.contents_encryption_mode ==
-			 policy->contents_encryption_mode) &&
-			(ctx.filenames_encryption_mode ==
-			 policy->filenames_encryption_mode));
+	return memcmp(ctx->master_key_descriptor, policy->master_key_descriptor,
+		      FS_KEY_DESCRIPTOR_SIZE) == 0 &&
+		(ctx->flags == policy->flags) &&
+		(ctx->contents_encryption_mode ==
+		 policy->contents_encryption_mode) &&
+		(ctx->filenames_encryption_mode ==
+		 policy->filenames_encryption_mode);
 }
 
 static int create_encryption_context_from_policy(struct inode *inode,
@@ -66,20 +49,12 @@ static int create_encryption_context_from_policy(struct inode *inode,
 					FS_KEY_DESCRIPTOR_SIZE);
 
 	if (!fscrypt_valid_contents_enc_mode(
-				policy->contents_encryption_mode)) {
-		printk(KERN_WARNING
-		       "%s: Invalid contents encryption mode %d\n", __func__,
-			policy->contents_encryption_mode);
+				policy->contents_encryption_mode))
 		return -EINVAL;
-	}
 
 	if (!fscrypt_valid_filenames_enc_mode(
-				policy->filenames_encryption_mode)) {
-		printk(KERN_WARNING
-			"%s: Invalid filenames encryption mode %d\n", __func__,
-			policy->filenames_encryption_mode);
+				policy->filenames_encryption_mode))
 		return -EINVAL;
-	}
 
 	if (policy->flags & ~FS_POLICY_FLAGS_VALID)
 		return -EINVAL;
@@ -98,6 +73,7 @@ int fscrypt_ioctl_set_policy(struct file *filp, const void __user *arg)
 	struct fscrypt_policy policy;
 	struct inode *inode = file_inode(filp);
 	int ret;
+	struct fscrypt_context ctx;
 
 	if (copy_from_user(&policy, arg, sizeof(policy)))
 		return -EFAULT;
@@ -114,9 +90,10 @@ int fscrypt_ioctl_set_policy(struct file *filp, const void __user *arg)
 
 	inode_lock(inode);
 
-	if (!inode_has_encryption_context(inode)) {
+	ret = inode->i_sb->s_cop->get_context(inode, &ctx, sizeof(ctx));
+	if (ret == -ENODATA) {
 		if (!S_ISDIR(inode->i_mode))
-			ret = -EINVAL;
+			ret = -ENOTDIR;
 		else if (!inode->i_sb->s_cop->empty_dir)
 			ret = -EOPNOTSUPP;
 		else if (!inode->i_sb->s_cop->empty_dir(inode))
@@ -124,12 +101,14 @@ int fscrypt_ioctl_set_policy(struct file *filp, const void __user *arg)
 		else
 			ret = create_encryption_context_from_policy(inode,
 								    &policy);
-	} else if (!is_encryption_context_consistent_with_policy(inode,
-								 &policy)) {
-		printk(KERN_WARNING
-		       "%s: Policy inconsistent with encryption context\n",
-		       __func__);
-		ret = -EINVAL;
+	} else if (ret == sizeof(ctx) &&
+		   is_encryption_context_consistent_with_policy(&ctx,
+								&policy)) {
+		/* The file already uses the same encryption policy. */
+		ret = 0;
+	} else if (ret >= 0 || ret == -ERANGE) {
+		/* The file already uses a different encryption policy. */
+		ret = -EEXIST;
 	}
 
 	inode_unlock(inode);
@@ -151,8 +130,10 @@ int fscrypt_ioctl_get_policy(struct file *filp, void __user *arg)
 		return -ENODATA;
 
 	res = inode->i_sb->s_cop->get_context(inode, &ctx, sizeof(ctx));
+	if (res < 0 && res != -ERANGE)
+		return res;
 	if (res != sizeof(ctx))
-		return -ENODATA;
+		return -EINVAL;
 	if (ctx.format != FS_ENCRYPTION_CONTEXT_FORMAT_V1)
 		return -EINVAL;
 
@@ -217,9 +198,9 @@ EXPORT_SYMBOL(fscrypt_has_permitted_context);
  * @parent: Parent inode from which the context is inherited.
  * @child:  Child inode that inherits the context from @parent.
  * @fs_data:  private data given by FS.
- * @preload:  preload child i_crypt_info
+ * @preload:  preload child i_crypt_info if true
  *
- * Return: Zero on success, non-zero otherwise
+ * Return: 0 on success, -errno on failure
  */
 int fscrypt_inherit_context(struct inode *parent, struct inode *child,
 						void *fs_data, bool preload)
@@ -240,19 +221,11 @@ int fscrypt_inherit_context(struct inode *parent, struct inode *child,
 		return -ENOKEY;
 
 	ctx.format = FS_ENCRYPTION_CONTEXT_FORMAT_V1;
-	if (fscrypt_dummy_context_enabled(parent)) {
-		ctx.contents_encryption_mode = FS_ENCRYPTION_MODE_AES_256_XTS;
-		ctx.filenames_encryption_mode = FS_ENCRYPTION_MODE_AES_256_CTS;
-		ctx.flags = 0;
-		memset(ctx.master_key_descriptor, 0x42, FS_KEY_DESCRIPTOR_SIZE);
-		res = 0;
-	} else {
-		ctx.contents_encryption_mode = ci->ci_data_mode;
-		ctx.filenames_encryption_mode = ci->ci_filename_mode;
-		ctx.flags = ci->ci_flags;
-		memcpy(ctx.master_key_descriptor, ci->ci_master_key,
-				FS_KEY_DESCRIPTOR_SIZE);
-	}
+	ctx.contents_encryption_mode = ci->ci_data_mode;
+	ctx.filenames_encryption_mode = ci->ci_filename_mode;
+	ctx.flags = ci->ci_flags;
+	memcpy(ctx.master_key_descriptor, ci->ci_master_key,
+	       FS_KEY_DESCRIPTOR_SIZE);
 	get_random_bytes(ctx.nonce, FS_KEY_DERIVATION_NONCE_SIZE);
 	res = parent->i_sb->s_cop->set_context(child, &ctx,
 						sizeof(ctx), fs_data);
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 2163c1e69f2a..6bcb9622fdf9 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -1343,11 +1343,6 @@ struct ext4_super_block {
 /* Number of quota types we support */
 #define EXT4_MAXQUOTAS 3
 
-#ifdef CONFIG_EXT4_FS_ENCRYPTION
-#define EXT4_KEY_DESC_PREFIX "ext4:"
-#define EXT4_KEY_DESC_PREFIX_SIZE 5
-#endif
-
 /*
  * fourth extended-fs super-block data in memory
  */
@@ -1517,12 +1512,6 @@ struct ext4_sb_info {
 
 	/* Barrier between changing inodes' journal flags and writepages ops. */
 	struct percpu_rw_semaphore s_journal_flag_rwsem;
-
-	/* Encryption support */
-#ifdef CONFIG_EXT4_FS_ENCRYPTION
-	u8 key_prefix[EXT4_KEY_DESC_PREFIX_SIZE];
-	u8 key_prefix_size;
-#endif
 };
 
 static inline struct ext4_sb_info *EXT4_SB(struct super_block *sb)
diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
index e57e8d90ea54..f372fc431b8e 100644
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -771,7 +771,7 @@ struct inode *__ext4_new_inode(handle_t *handle, struct inode *dir,
 		if (err)
 			return ERR_PTR(err);
 		if (!fscrypt_has_encryption_key(dir))
-			return ERR_PTR(-EPERM);
+			return ERR_PTR(-ENOKEY);
 		if (!handle)
 			nblocks += EXT4_DATA_TRANS_BLOCKS(dir->i_sb);
 		encrypt = 1;
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index eadba919f26b..bb880c326191 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -1378,6 +1378,8 @@ static struct buffer_head * ext4_find_entry (struct inode *dir,
 		return NULL;
 
 	retval = ext4_fname_setup_filename(dir, d_name, 1, &fname);
+	if (retval == -ENOENT)
+		return NULL;
 	if (retval)
 		return ERR_PTR(retval);
 
@@ -3088,7 +3090,7 @@ static int ext4_symlink(struct inode *dir,
 		if (err)
 			return err;
 		if (!fscrypt_has_encryption_key(dir))
-			return -EPERM;
+			return -ENOKEY;
 		disk_link.len = (fscrypt_fname_encrypted_size(dir, len) +
 				 sizeof(struct fscrypt_symlink_data));
 		sd = kzalloc(disk_link.len, GFP_KERNEL);
@@ -3525,6 +3527,12 @@ static int ext4_rename(struct inode *old_dir, struct dentry *old_dentry,
 			EXT4_I(old_dentry->d_inode)->i_projid)))
 		return -EXDEV;
 
+	if ((ext4_encrypted_inode(old_dir) &&
+	     !fscrypt_has_encryption_key(old_dir)) ||
+	    (ext4_encrypted_inode(new_dir) &&
+	     !fscrypt_has_encryption_key(new_dir)))
+		return -ENOKEY;
+
 	retval = dquot_initialize(old.dir);
 	if (retval)
 		return retval;
@@ -3725,6 +3733,12 @@ static int ext4_cross_rename(struct inode *old_dir, struct dentry *old_dentry,
 	int retval;
 	struct timespec ctime;
 
+	if ((ext4_encrypted_inode(old_dir) &&
+	     !fscrypt_has_encryption_key(old_dir)) ||
+	    (ext4_encrypted_inode(new_dir) &&
+	     !fscrypt_has_encryption_key(new_dir)))
+		return -ENOKEY;
+
 	if ((ext4_encrypted_inode(old_dir) ||
 	     ext4_encrypted_inode(new_dir)) &&
 	    (old_dir != new_dir) &&
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 66845a08a87a..9d15a6293124 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1100,12 +1100,6 @@ static int ext4_get_context(struct inode *inode, void *ctx, size_t len)
 				 EXT4_XATTR_NAME_ENCRYPTION_CONTEXT, ctx, len);
 }
 
-static int ext4_key_prefix(struct inode *inode, u8 **key)
-{
-	*key = EXT4_SB(inode->i_sb)->key_prefix;
-	return EXT4_SB(inode->i_sb)->key_prefix_size;
-}
-
 static int ext4_prepare_context(struct inode *inode)
 {
 	return ext4_convert_inline_data(inode);
@@ -1180,8 +1174,8 @@ static unsigned ext4_max_namelen(struct inode *inode)
 }
 
 static struct fscrypt_operations ext4_cryptops = {
+	.key_prefix		= "ext4:",
 	.get_context		= ext4_get_context,
-	.key_prefix		= ext4_key_prefix,
 	.prepare_context	= ext4_prepare_context,
 	.set_context		= ext4_set_context,
 	.dummy_context		= ext4_dummy_context,
@@ -4218,11 +4212,6 @@ no_journal:
 	ratelimit_state_init(&sbi->s_msg_ratelimit_state, 5 * HZ, 10);
 
 	kfree(orig_data);
-#ifdef CONFIG_EXT4_FS_ENCRYPTION
-	memcpy(sbi->key_prefix, EXT4_KEY_DESC_PREFIX,
-				EXT4_KEY_DESC_PREFIX_SIZE);
-	sbi->key_prefix_size = EXT4_KEY_DESC_PREFIX_SIZE;
-#endif
 	return 0;
 
 cantfind_ext4:
diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c
index 827c5daef4fc..18607fc5240d 100644
--- a/fs/f2fs/dir.c
+++ b/fs/f2fs/dir.c
@@ -268,7 +268,10 @@ struct f2fs_dir_entry *f2fs_find_entry(struct inode *dir,
 
 	err = fscrypt_setup_filename(dir, child, 1, &fname);
 	if (err) {
-		*res_page = ERR_PTR(err);
+		if (err == -ENOENT)
+			*res_page = NULL;
+		else
+			*res_page = ERR_PTR(err);
 		return NULL;
 	}
 
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 2da8c3aa0ce5..93d38d854a41 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -760,10 +760,6 @@ enum {
 	MAX_TIME,
 };
 
-#ifdef CONFIG_F2FS_FS_ENCRYPTION
-#define F2FS_KEY_DESC_PREFIX "f2fs:"
-#define F2FS_KEY_DESC_PREFIX_SIZE 5
-#endif
 struct f2fs_sb_info {
 	struct super_block *sb;			/* pointer to VFS super block */
 	struct proc_dir_entry *s_proc;		/* proc entry */
@@ -771,11 +767,6 @@ struct f2fs_sb_info {
 	int valid_super_block;			/* valid super block no */
 	unsigned long s_flag;				/* flags for sbi */
 
-#ifdef CONFIG_F2FS_FS_ENCRYPTION
-	u8 key_prefix[F2FS_KEY_DESC_PREFIX_SIZE];
-	u8 key_prefix_size;
-#endif
-
 #ifdef CONFIG_BLK_DEV_ZONED
 	unsigned int blocks_per_blkz;		/* F2FS blocks per zone */
 	unsigned int log_blocks_per_blkz;	/* log2 F2FS blocks per zone */
diff --git a/fs/f2fs/namei.c b/fs/f2fs/namei.c
index 56c19b0610a8..11cabcadb1a3 100644
--- a/fs/f2fs/namei.c
+++ b/fs/f2fs/namei.c
@@ -403,7 +403,7 @@ static int f2fs_symlink(struct inode *dir, struct dentry *dentry,
 			return err;
 
 		if (!fscrypt_has_encryption_key(dir))
-			return -EPERM;
+			return -ENOKEY;
 
 		disk_link.len = (fscrypt_fname_encrypted_size(dir, len) +
 				sizeof(struct fscrypt_symlink_data));
@@ -447,7 +447,7 @@ static int f2fs_symlink(struct inode *dir, struct dentry *dentry,
 			goto err_out;
 
 		if (!fscrypt_has_encryption_key(inode)) {
-			err = -EPERM;
+			err = -ENOKEY;
 			goto err_out;
 		}
 
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 702638e21c76..739192d95e71 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -1156,12 +1156,6 @@ static int f2fs_get_context(struct inode *inode, void *ctx, size_t len)
 				ctx, len, NULL);
 }
 
-static int f2fs_key_prefix(struct inode *inode, u8 **key)
-{
-	*key = F2FS_I_SB(inode)->key_prefix;
-	return F2FS_I_SB(inode)->key_prefix_size;
-}
-
 static int f2fs_set_context(struct inode *inode, const void *ctx, size_t len,
 							void *fs_data)
 {
@@ -1177,8 +1171,8 @@ static unsigned f2fs_max_namelen(struct inode *inode)
 }
 
 static struct fscrypt_operations f2fs_cryptops = {
+	.key_prefix	= "f2fs:",
 	.get_context	= f2fs_get_context,
-	.key_prefix	= f2fs_key_prefix,
 	.set_context	= f2fs_set_context,
 	.is_encrypted	= f2fs_encrypted_inode,
 	.empty_dir	= f2fs_empty_dir,
@@ -1518,12 +1512,6 @@ static void init_sb_info(struct f2fs_sb_info *sbi)
 	mutex_init(&sbi->wio_mutex[NODE]);
 	mutex_init(&sbi->wio_mutex[DATA]);
 	spin_lock_init(&sbi->cp_lock);
-
-#ifdef CONFIG_F2FS_FS_ENCRYPTION
-	memcpy(sbi->key_prefix, F2FS_KEY_DESC_PREFIX,
-				F2FS_KEY_DESC_PREFIX_SIZE);
-	sbi->key_prefix_size = F2FS_KEY_DESC_PREFIX_SIZE;
-#endif
 }
 
 static int init_percpu_info(struct f2fs_sb_info *sbi)
diff --git a/fs/ubifs/crypto.c b/fs/ubifs/crypto.c
index 3402720f2b28..6335abcf98df 100644
--- a/fs/ubifs/crypto.c
+++ b/fs/ubifs/crypto.c
@@ -26,15 +26,6 @@ static unsigned int ubifs_crypt_max_namelen(struct inode *inode)
 		return UBIFS_MAX_NLEN;
 }
 
-static int ubifs_key_prefix(struct inode *inode, u8 **key)
-{
-	static char prefix[] = "ubifs:";
-
-	*key = prefix;
-
-	return sizeof(prefix) - 1;
-}
-
 int ubifs_encrypt(const struct inode *inode, struct ubifs_data_node *dn,
 		  unsigned int in_len, unsigned int *out_len, int block)
 {
@@ -88,10 +79,10 @@ int ubifs_decrypt(const struct inode *inode, struct ubifs_data_node *dn,
 
 struct fscrypt_operations ubifs_crypt_operations = {
 	.flags			= FS_CFLG_OWN_PAGES,
+	.key_prefix		= "ubifs:",
 	.get_context		= ubifs_crypt_get_context,
 	.set_context		= ubifs_crypt_set_context,
 	.is_encrypted		= __ubifs_crypt_is_encrypted,
 	.empty_dir		= ubifs_crypt_empty_dir,
 	.max_namelen		= ubifs_crypt_max_namelen,
-	.key_prefix		= ubifs_key_prefix,
 };
diff --git a/include/linux/fscrypto.h b/include/linux/fscrypto.h
index c074b670aa99..715f17b3c6d7 100644
--- a/include/linux/fscrypto.h
+++ b/include/linux/fscrypto.h
@@ -35,7 +35,6 @@ struct fscrypt_ctx {
 		struct list_head free_list;	/* Free list */
 	};
 	u8 flags;				/* Flags */
-	u8 mode;				/* Encryption mode for tfm */
 };
 
 /**
@@ -86,8 +85,8 @@ struct fscrypt_name {
  */
 struct fscrypt_operations {
 	unsigned int flags;
+	const char *key_prefix;
 	int (*get_context)(struct inode *, void *, size_t);
-	int (*key_prefix)(struct inode *, u8 **);
 	int (*prepare_context)(struct inode *);
 	int (*set_context)(struct inode *, const void *, size_t, void *);
 	int (*dummy_context)(struct inode *);
@@ -174,11 +173,8 @@ 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 +197,12 @@ 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 */