Received-SPF: pass (google.com: domain of linux-ext4-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Date:   Mon, 14 Sep 2020 10:31:28 -0700
From:   Jaegeuk Kim <jaegeuk@kernel.org>
To:     Eric Biggers <ebiggers@kernel.org>
Cc:     linux-fscrypt@vger.kernel.org,
        Daniel Rosenberg <drosen@google.com>,
        Jeff Layton <jlayton@kernel.org>,
        linux-f2fs-devel@lists.sourceforge.net,
        linux-mtd@lists.infradead.org, ceph-devel@vger.kernel.org,
        linux-ext4@vger.kernel.org
Subject: Re: [f2fs-dev] [PATCH v2 11/11] fscrypt: handle
 test_dummy_encryption in more logical way
Message-ID: <20200914173128.GB2580525@google.com>
References: <20200913083620.170627-1-ebiggers@kernel.org>
 <20200913083620.170627-12-ebiggers@kernel.org>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20200913083620.170627-12-ebiggers@kernel.org>
Sender: linux-ext4-owner@vger.kernel.org
Precedence: bulk

On 09/13, Eric Biggers wrote:
> From: Eric Biggers <ebiggers@google.com>
> 
> The behavior of the test_dummy_encryption mount option is that when a
> new file (or directory or symlink) is created in an unencrypted
> directory, it's automatically encrypted using a dummy encryption policy.
> That's it; in particular, the encryption (or lack thereof) of existing
> files (or directories or symlinks) doesn't change.
> 
> Unfortunately the implementation of test_dummy_encryption is a bit weird
> and confusing.  When test_dummy_encryption is enabled and a file is
> being created in an unencrypted directory, we set up an encryption key
> (->i_crypt_info) for the directory.  This isn't actually used to do any
> encryption, however, since the directory is still unencrypted!  Instead,
> ->i_crypt_info is only used for inheriting the encryption policy.
> 
> One consequence of this is that the filesystem ends up providing a
> "dummy context" (policy + nonce) instead of a "dummy policy".  In
> commit ed318a6cc0b6 ("fscrypt: support test_dummy_encryption=v2"), I
> mistakenly thought this was required.  However, actually the nonce only
> ends up being used to derive a key that is never used.
> 
> Another consequence of this implementation is that it allows for
> 'inode->i_crypt_info != NULL && !IS_ENCRYPTED(inode)', which is an edge
> case that can be forgotten about.  For example, currently
> FS_IOC_GET_ENCRYPTION_POLICY on an unencrypted directory may return the
> dummy encryption policy when the filesystem is mounted with
> test_dummy_encryption.  That seems like the wrong thing to do, since
> again, the directory itself is not actually encrypted.
> 
> Therefore, switch to a more logical and maintainable implementation
> where the dummy encryption policy inheritance is done without setting up
> keys for unencrypted directories.  This involves:
> 
> - Adding a function fscrypt_policy_to_inherit() which returns the
>   encryption policy to inherit from a directory.  This can be a real
>   policy, a dummy policy, or no policy.
> 
> - Replacing struct fscrypt_dummy_context, ->get_dummy_context(), etc.
>   with struct fscrypt_dummy_policy, ->get_dummy_policy(), etc.
> 
> - Making fscrypt_fname_encrypted_size() take an fscrypt_policy instead
>   of an inode.
> 
> Signed-off-by: Eric Biggers <ebiggers@google.com>

For F2FS part, looks good to me.

Acked-by: Jaegeuk Kim <jaegeuk@kernel.org>

> ---
>  fs/crypto/fname.c           |  11 ++--
>  fs/crypto/fscrypt_private.h |   6 +-
>  fs/crypto/hooks.c           |  30 ++++------
>  fs/crypto/keysetup.c        |  33 +++--------
>  fs/crypto/policy.c          | 113 ++++++++++++++++++++++--------------
>  fs/ext4/ext4.h              |   6 +-
>  fs/ext4/super.c             |  17 +++---
>  fs/f2fs/f2fs.h              |   2 +-
>  fs/f2fs/super.c             |  16 ++---
>  include/linux/fscrypt.h     |  40 +++++--------
>  10 files changed, 134 insertions(+), 140 deletions(-)
> 
> diff --git a/fs/crypto/fname.c b/fs/crypto/fname.c
> index 47bcfddb278ba..eb13408b50a70 100644
> --- a/fs/crypto/fname.c
> +++ b/fs/crypto/fname.c
> @@ -242,11 +242,11 @@ static int base64_decode(const char *src, int len, u8 *dst)
>  	return cp - dst;
>  }
>  
> -bool fscrypt_fname_encrypted_size(const struct inode *inode, u32 orig_len,
> -				  u32 max_len, u32 *encrypted_len_ret)
> +bool fscrypt_fname_encrypted_size(const union fscrypt_policy *policy,
> +				  u32 orig_len, u32 max_len,
> +				  u32 *encrypted_len_ret)
>  {
> -	const struct fscrypt_info *ci = inode->i_crypt_info;
> -	int padding = 4 << (fscrypt_policy_flags(&ci->ci_policy) &
> +	int padding = 4 << (fscrypt_policy_flags(policy) &
>  			    FSCRYPT_POLICY_FLAGS_PAD_MASK);
>  	u32 encrypted_len;
>  
> @@ -418,7 +418,8 @@ int fscrypt_setup_filename(struct inode *dir, const struct qstr *iname,
>  		return ret;
>  
>  	if (fscrypt_has_encryption_key(dir)) {
> -		if (!fscrypt_fname_encrypted_size(dir, iname->len,
> +		if (!fscrypt_fname_encrypted_size(&dir->i_crypt_info->ci_policy,
> +						  iname->len,
>  						  dir->i_sb->s_cop->max_namelen,
>  						  &fname->crypto_buf.len))
>  			return -ENAMETOOLONG;
> diff --git a/fs/crypto/fscrypt_private.h b/fs/crypto/fscrypt_private.h
> index ac3352086ee44..4f5806a3b73d7 100644
> --- a/fs/crypto/fscrypt_private.h
> +++ b/fs/crypto/fscrypt_private.h
> @@ -291,8 +291,9 @@ void fscrypt_generate_iv(union fscrypt_iv *iv, u64 lblk_num,
>  /* fname.c */
>  int fscrypt_fname_encrypt(const struct inode *inode, const struct qstr *iname,
>  			  u8 *out, unsigned int olen);
> -bool fscrypt_fname_encrypted_size(const struct inode *inode, u32 orig_len,
> -				  u32 max_len, u32 *encrypted_len_ret);
> +bool fscrypt_fname_encrypted_size(const union fscrypt_policy *policy,
> +				  u32 orig_len, u32 max_len,
> +				  u32 *encrypted_len_ret);
>  extern const struct dentry_operations fscrypt_d_ops;
>  
>  /* hkdf.c */
> @@ -592,5 +593,6 @@ bool fscrypt_supported_policy(const union fscrypt_policy *policy_u,
>  int fscrypt_policy_from_context(union fscrypt_policy *policy_u,
>  				const union fscrypt_context *ctx_u,
>  				int ctx_size);
> +const union fscrypt_policy *fscrypt_policy_to_inherit(struct inode *dir);
>  
>  #endif /* _FSCRYPT_PRIVATE_H */
> diff --git a/fs/crypto/hooks.c b/fs/crypto/hooks.c
> index a399c54947f28..42f5ee9f592d1 100644
> --- a/fs/crypto/hooks.c
> +++ b/fs/crypto/hooks.c
> @@ -193,30 +193,24 @@ int fscrypt_prepare_symlink(struct inode *dir, const char *target,
>  			    unsigned int len, unsigned int max_len,
>  			    struct fscrypt_str *disk_link)
>  {
> -	int err;
> +	const union fscrypt_policy *policy;
>  
> -	if (!IS_ENCRYPTED(dir) && !fscrypt_get_dummy_context(dir->i_sb)) {
> +	/*
> +	 * To calculate the size of the encrypted symlink target we need to know
> +	 * the amount of NUL padding, which is determined by the flags set in
> +	 * the encryption policy which will be inherited from the directory.
> +	 */
> +	policy = fscrypt_policy_to_inherit(dir);
> +	if (policy == NULL) {
> +		/* Not encrypted */
>  		disk_link->name = (unsigned char *)target;
>  		disk_link->len = len + 1;
>  		if (disk_link->len > max_len)
>  			return -ENAMETOOLONG;
>  		return 0;
>  	}
> -
> -	/*
> -	 * To calculate the size of the encrypted symlink target we need to know
> -	 * the amount of NUL padding, which is determined by the flags set in
> -	 * the encryption policy which will be inherited from the directory.
> -	 * The easiest way to get access to this is to just load the directory's
> -	 * fscrypt_info, since we'll need it to create the dir_entry anyway.
> -	 *
> -	 * Note: in test_dummy_encryption mode, @dir may be unencrypted.
> -	 */
> -	err = fscrypt_get_encryption_info(dir);
> -	if (err)
> -		return err;
> -	if (!fscrypt_has_encryption_key(dir))
> -		return -ENOKEY;
> +	if (IS_ERR(policy))
> +		return PTR_ERR(policy);
>  
>  	/*
>  	 * Calculate the size of the encrypted symlink and verify it won't
> @@ -229,7 +223,7 @@ int fscrypt_prepare_symlink(struct inode *dir, const char *target,
>  	 * counting it (even though it is meaningless for ciphertext) is simpler
>  	 * for now since filesystems will assume it is there and subtract it.
>  	 */
> -	if (!fscrypt_fname_encrypted_size(dir, len,
> +	if (!fscrypt_fname_encrypted_size(policy, len,
>  					  max_len - sizeof(struct fscrypt_symlink_data),
>  					  &disk_link->len))
>  		return -ENAMETOOLONG;
> diff --git a/fs/crypto/keysetup.c b/fs/crypto/keysetup.c
> index 7f5fbc2654d57..f38fb71501ae9 100644
> --- a/fs/crypto/keysetup.c
> +++ b/fs/crypto/keysetup.c
> @@ -545,7 +545,7 @@ fscrypt_setup_encryption_info(struct inode *inode,
>  
>  /**
>   * fscrypt_get_encryption_info() - set up an inode's encryption key
> - * @inode: the inode to set up the key for
> + * @inode: the inode to set up the key for.  Must be encrypted.
>   *
>   * Set up ->i_crypt_info, if it hasn't already been done.
>   *
> @@ -567,18 +567,8 @@ int fscrypt_get_encryption_info(struct inode *inode)
>  
>  	res = inode->i_sb->s_cop->get_context(inode, &ctx, sizeof(ctx));
>  	if (res < 0) {
> -		const union fscrypt_context *dummy_ctx =
> -			fscrypt_get_dummy_context(inode->i_sb);
> -
> -		if (IS_ENCRYPTED(inode) || !dummy_ctx) {
> -			fscrypt_warn(inode,
> -				     "Error %d getting encryption context",
> -				     res);
> -			return res;
> -		}
> -		/* Fake up a context for an unencrypted directory */
> -		res = fscrypt_context_size(dummy_ctx);
> -		memcpy(&ctx, dummy_ctx, res);
> +		fscrypt_warn(inode, "Error %d getting encryption context", res);
> +		return res;
>  	}
>  
>  	res = fscrypt_policy_from_context(&policy, &ctx, res);
> @@ -620,17 +610,14 @@ EXPORT_SYMBOL(fscrypt_get_encryption_info);
>  int fscrypt_prepare_new_inode(struct inode *dir, struct inode *inode,
>  			      bool *encrypt_ret)
>  {
> -	int err;
> +	const union fscrypt_policy *policy;
>  	u8 nonce[FSCRYPT_FILE_NONCE_SIZE];
>  
> -	if (!IS_ENCRYPTED(dir) && fscrypt_get_dummy_context(dir->i_sb) == NULL)
> +	policy = fscrypt_policy_to_inherit(dir);
> +	if (policy == NULL)
>  		return 0;
> -
> -	err = fscrypt_get_encryption_info(dir);
> -	if (err)
> -		return err;
> -	if (!fscrypt_has_encryption_key(dir))
> -		return -ENOKEY;
> +	if (IS_ERR(policy))
> +		return PTR_ERR(policy);
>  
>  	if (WARN_ON_ONCE(inode->i_mode == 0))
>  		return -EINVAL;
> @@ -647,9 +634,7 @@ int fscrypt_prepare_new_inode(struct inode *dir, struct inode *inode,
>  	*encrypt_ret = true;
>  
>  	get_random_bytes(nonce, FSCRYPT_FILE_NONCE_SIZE);
> -	return fscrypt_setup_encryption_info(inode,
> -					     &dir->i_crypt_info->ci_policy,
> -					     nonce);
> +	return fscrypt_setup_encryption_info(inode, policy, nonce);
>  }
>  EXPORT_SYMBOL_GPL(fscrypt_prepare_new_inode);
>  
> diff --git a/fs/crypto/policy.c b/fs/crypto/policy.c
> index 4ff893f7b030a..97cf07543651f 100644
> --- a/fs/crypto/policy.c
> +++ b/fs/crypto/policy.c
> @@ -32,6 +32,14 @@ bool fscrypt_policies_equal(const union fscrypt_policy *policy1,
>  	return !memcmp(policy1, policy2, fscrypt_policy_size(policy1));
>  }
>  
> +static const union fscrypt_policy *
> +fscrypt_get_dummy_policy(struct super_block *sb)
> +{
> +	if (!sb->s_cop->get_dummy_policy)
> +		return NULL;
> +	return sb->s_cop->get_dummy_policy(sb);
> +}
> +
>  static bool fscrypt_valid_enc_modes(u32 contents_mode, u32 filenames_mode)
>  {
>  	if (contents_mode == FSCRYPT_MODE_AES_256_XTS &&
> @@ -628,6 +636,25 @@ int fscrypt_has_permitted_context(struct inode *parent, struct inode *child)
>  }
>  EXPORT_SYMBOL(fscrypt_has_permitted_context);
>  
> +/*
> + * Return the encryption policy that new files in the directory will inherit, or
> + * NULL if none, or an ERR_PTR() on error.  If the directory is encrypted, also
> + * ensure that its key is set up, so that the new filename can be encrypted.
> + */
> +const union fscrypt_policy *fscrypt_policy_to_inherit(struct inode *dir)
> +{
> +	int err;
> +
> +	if (IS_ENCRYPTED(dir)) {
> +		err = fscrypt_require_key(dir);
> +		if (err)
> +			return ERR_PTR(err);
> +		return &dir->i_crypt_info->ci_policy;
> +	}
> +
> +	return fscrypt_get_dummy_policy(dir->i_sb);
> +}
> +
>  /**
>   * fscrypt_set_context() - Set the fscrypt context of a new inode
>   * @inode: a new inode
> @@ -672,31 +699,28 @@ EXPORT_SYMBOL_GPL(fscrypt_set_context);
>   * @sb: the filesystem on which test_dummy_encryption is being specified
>   * @arg: the argument to the test_dummy_encryption option.
>   *	 If no argument was specified, then @arg->from == NULL.
> - * @dummy_ctx: the filesystem's current dummy context (input/output, see below)
> + * @dummy_policy: the filesystem's current dummy policy (input/output, see
> + *		  below)
>   *
>   * Handle the test_dummy_encryption mount option by creating a dummy encryption
> - * context, saving it in @dummy_ctx, and adding the corresponding dummy
> - * encryption key to the filesystem.  If the @dummy_ctx is already set, then
> + * policy, saving it in @dummy_policy, and adding the corresponding dummy
> + * encryption key to the filesystem.  If the @dummy_policy is already set, then
>   * instead validate that it matches @arg.  Don't support changing it via
>   * remount, as that is difficult to do safely.
>   *
> - * The reason we use an fscrypt_context rather than an fscrypt_policy is because
> - * we mustn't generate a new nonce each time we access a dummy-encrypted
> - * directory, as that would change the way filenames are encrypted.
> - *
> - * Return: 0 on success (dummy context set, or the same context is already set);
> - *         -EEXIST if a different dummy context is already set;
> + * Return: 0 on success (dummy policy set, or the same policy is already set);
> + *         -EEXIST if a different dummy policy is already set;
>   *         or another -errno value.
>   */
>  int fscrypt_set_test_dummy_encryption(struct super_block *sb,
>  				      const substring_t *arg,
> -				      struct fscrypt_dummy_context *dummy_ctx)
> +				      struct fscrypt_dummy_policy *dummy_policy)
>  {
>  	const char *argstr = "v2";
>  	const char *argstr_to_free = NULL;
>  	struct fscrypt_key_specifier key_spec = { 0 };
>  	int version;
> -	union fscrypt_context *ctx = NULL;
> +	union fscrypt_policy *policy = NULL;
>  	int err;
>  
>  	if (arg->from) {
> @@ -706,12 +730,12 @@ int fscrypt_set_test_dummy_encryption(struct super_block *sb,
>  	}
>  
>  	if (!strcmp(argstr, "v1")) {
> -		version = FSCRYPT_CONTEXT_V1;
> +		version = FSCRYPT_POLICY_V1;
>  		key_spec.type = FSCRYPT_KEY_SPEC_TYPE_DESCRIPTOR;
>  		memset(key_spec.u.descriptor, 0x42,
>  		       FSCRYPT_KEY_DESCRIPTOR_SIZE);
>  	} else if (!strcmp(argstr, "v2")) {
> -		version = FSCRYPT_CONTEXT_V2;
> +		version = FSCRYPT_POLICY_V2;
>  		key_spec.type = FSCRYPT_KEY_SPEC_TYPE_IDENTIFIER;
>  		/* key_spec.u.identifier gets filled in when adding the key */
>  	} else {
> @@ -719,21 +743,8 @@ int fscrypt_set_test_dummy_encryption(struct super_block *sb,
>  		goto out;
>  	}
>  
> -	if (dummy_ctx->ctx) {
> -		/*
> -		 * Note: if we ever make test_dummy_encryption support
> -		 * specifying other encryption settings, such as the encryption
> -		 * modes, we'll need to compare those settings here.
> -		 */
> -		if (dummy_ctx->ctx->version == version)
> -			err = 0;
> -		else
> -			err = -EEXIST;
> -		goto out;
> -	}
> -
> -	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
> -	if (!ctx) {
> +	policy = kzalloc(sizeof(*policy), GFP_KERNEL);
> +	if (!policy) {
>  		err = -ENOMEM;
>  		goto out;
>  	}
> @@ -742,18 +753,18 @@ int fscrypt_set_test_dummy_encryption(struct super_block *sb,
>  	if (err)
>  		goto out;
>  
> -	ctx->version = version;
> -	switch (ctx->version) {
> -	case FSCRYPT_CONTEXT_V1:
> -		ctx->v1.contents_encryption_mode = FSCRYPT_MODE_AES_256_XTS;
> -		ctx->v1.filenames_encryption_mode = FSCRYPT_MODE_AES_256_CTS;
> -		memcpy(ctx->v1.master_key_descriptor, key_spec.u.descriptor,
> +	policy->version = version;
> +	switch (policy->version) {
> +	case FSCRYPT_POLICY_V1:
> +		policy->v1.contents_encryption_mode = FSCRYPT_MODE_AES_256_XTS;
> +		policy->v1.filenames_encryption_mode = FSCRYPT_MODE_AES_256_CTS;
> +		memcpy(policy->v1.master_key_descriptor, key_spec.u.descriptor,
>  		       FSCRYPT_KEY_DESCRIPTOR_SIZE);
>  		break;
> -	case FSCRYPT_CONTEXT_V2:
> -		ctx->v2.contents_encryption_mode = FSCRYPT_MODE_AES_256_XTS;
> -		ctx->v2.filenames_encryption_mode = FSCRYPT_MODE_AES_256_CTS;
> -		memcpy(ctx->v2.master_key_identifier, key_spec.u.identifier,
> +	case FSCRYPT_POLICY_V2:
> +		policy->v2.contents_encryption_mode = FSCRYPT_MODE_AES_256_XTS;
> +		policy->v2.filenames_encryption_mode = FSCRYPT_MODE_AES_256_CTS;
> +		memcpy(policy->v2.master_key_identifier, key_spec.u.identifier,
>  		       FSCRYPT_KEY_IDENTIFIER_SIZE);
>  		break;
>  	default:
> @@ -761,11 +772,19 @@ int fscrypt_set_test_dummy_encryption(struct super_block *sb,
>  		err = -EINVAL;
>  		goto out;
>  	}
> -	dummy_ctx->ctx = ctx;
> -	ctx = NULL;
> +
> +	if (dummy_policy->policy) {
> +		if (fscrypt_policies_equal(policy, dummy_policy->policy))
> +			err = 0;
> +		else
> +			err = -EEXIST;
> +		goto out;
> +	}
> +	dummy_policy->policy = policy;
> +	policy = NULL;
>  	err = 0;
>  out:
> -	kfree(ctx);
> +	kfree(policy);
>  	kfree(argstr_to_free);
>  	return err;
>  }
> @@ -783,10 +802,16 @@ EXPORT_SYMBOL_GPL(fscrypt_set_test_dummy_encryption);
>  void fscrypt_show_test_dummy_encryption(struct seq_file *seq, char sep,
>  					struct super_block *sb)
>  {
> -	const union fscrypt_context *ctx = fscrypt_get_dummy_context(sb);
> +	const union fscrypt_policy *policy = fscrypt_get_dummy_policy(sb);
> +	int vers;
>  
> -	if (!ctx)
> +	if (!policy)
>  		return;
> -	seq_printf(seq, "%ctest_dummy_encryption=v%d", sep, ctx->version);
> +
> +	vers = policy->version;
> +	if (vers == FSCRYPT_POLICY_V1) /* Handle numbering quirk */
> +		vers = 1;
> +
> +	seq_printf(seq, "%ctest_dummy_encryption=v%d", sep, vers);
>  }
>  EXPORT_SYMBOL_GPL(fscrypt_show_test_dummy_encryption);
> diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
> index 523e00d7b3924..f9a692c0a66c3 100644
> --- a/fs/ext4/ext4.h
> +++ b/fs/ext4/ext4.h
> @@ -1401,7 +1401,7 @@ struct ext4_super_block {
>  #define EXT4_MF_FS_ABORTED		0x0002	/* Fatal error detected */
>  
>  #ifdef CONFIG_FS_ENCRYPTION
> -#define DUMMY_ENCRYPTION_ENABLED(sbi) ((sbi)->s_dummy_enc_ctx.ctx != NULL)
> +#define DUMMY_ENCRYPTION_ENABLED(sbi) ((sbi)->s_dummy_enc_policy.policy != NULL)
>  #else
>  #define DUMMY_ENCRYPTION_ENABLED(sbi) (0)
>  #endif
> @@ -1596,8 +1596,8 @@ struct ext4_sb_info {
>  	atomic_t s_warning_count;
>  	atomic_t s_msg_count;
>  
> -	/* Encryption context for '-o test_dummy_encryption' */
> -	struct fscrypt_dummy_context s_dummy_enc_ctx;
> +	/* Encryption policy for '-o test_dummy_encryption' */
> +	struct fscrypt_dummy_policy s_dummy_enc_policy;
>  
>  	/*
>  	 * Barrier between writepages ops and changing any inode's JOURNAL_DATA
> diff --git a/fs/ext4/super.c b/fs/ext4/super.c
> index ea425b49b3456..7e77722406e2f 100644
> --- a/fs/ext4/super.c
> +++ b/fs/ext4/super.c
> @@ -1104,7 +1104,7 @@ static void ext4_put_super(struct super_block *sb)
>  		crypto_free_shash(sbi->s_chksum_driver);
>  	kfree(sbi->s_blockgroup_lock);
>  	fs_put_dax(sbi->s_daxdev);
> -	fscrypt_free_dummy_context(&sbi->s_dummy_enc_ctx);
> +	fscrypt_free_dummy_policy(&sbi->s_dummy_enc_policy);
>  #ifdef CONFIG_UNICODE
>  	utf8_unload(sbi->s_encoding);
>  #endif
> @@ -1392,10 +1392,10 @@ static int ext4_set_context(struct inode *inode, const void *ctx, size_t len,
>  	return res;
>  }
>  
> -static const union fscrypt_context *
> -ext4_get_dummy_context(struct super_block *sb)
> +static const union fscrypt_policy *
> +ext4_get_dummy_policy(struct super_block *sb)
>  {
> -	return EXT4_SB(sb)->s_dummy_enc_ctx.ctx;
> +	return EXT4_SB(sb)->s_dummy_enc_policy.policy;
>  }
>  
>  static bool ext4_has_stable_inodes(struct super_block *sb)
> @@ -1414,7 +1414,7 @@ static const struct fscrypt_operations ext4_cryptops = {
>  	.key_prefix		= "ext4:",
>  	.get_context		= ext4_get_context,
>  	.set_context		= ext4_set_context,
> -	.get_dummy_context	= ext4_get_dummy_context,
> +	.get_dummy_policy	= ext4_get_dummy_policy,
>  	.empty_dir		= ext4_empty_dir,
>  	.max_namelen		= EXT4_NAME_LEN,
>  	.has_stable_inodes	= ext4_has_stable_inodes,
> @@ -1888,12 +1888,13 @@ static int ext4_set_test_dummy_encryption(struct super_block *sb,
>  	 * needed to allow it to be set or changed during remount.  We do allow
>  	 * it to be specified during remount, but only if there is no change.
>  	 */
> -	if (is_remount && !sbi->s_dummy_enc_ctx.ctx) {
> +	if (is_remount && !sbi->s_dummy_enc_policy.policy) {
>  		ext4_msg(sb, KERN_WARNING,
>  			 "Can't set test_dummy_encryption on remount");
>  		return -1;
>  	}
> -	err = fscrypt_set_test_dummy_encryption(sb, arg, &sbi->s_dummy_enc_ctx);
> +	err = fscrypt_set_test_dummy_encryption(sb, arg,
> +						&sbi->s_dummy_enc_policy);
>  	if (err) {
>  		if (err == -EEXIST)
>  			ext4_msg(sb, KERN_WARNING,
> @@ -4935,7 +4936,7 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
>  	for (i = 0; i < EXT4_MAXQUOTAS; i++)
>  		kfree(get_qf_name(sb, sbi, i));
>  #endif
> -	fscrypt_free_dummy_context(&sbi->s_dummy_enc_ctx);
> +	fscrypt_free_dummy_policy(&sbi->s_dummy_enc_policy);
>  	ext4_blkdev_remove(sbi);
>  	brelse(bh);
>  out_fail:
> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> index 0503371f88ed4..7c089ff7ff943 100644
> --- a/fs/f2fs/f2fs.h
> +++ b/fs/f2fs/f2fs.h
> @@ -138,7 +138,7 @@ struct f2fs_mount_info {
>  	int fsync_mode;			/* fsync policy */
>  	int fs_mode;			/* fs mode: LFS or ADAPTIVE */
>  	int bggc_mode;			/* bggc mode: off, on or sync */
> -	struct fscrypt_dummy_context dummy_enc_ctx; /* test dummy encryption */
> +	struct fscrypt_dummy_policy dummy_enc_policy; /* test dummy encryption */
>  	block_t unusable_cap_perc;	/* percentage for cap */
>  	block_t unusable_cap;		/* Amount of space allowed to be
>  					 * unusable when disabling checkpoint
> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
> index dfa072fa80815..f2b3d1a279fb7 100644
> --- a/fs/f2fs/super.c
> +++ b/fs/f2fs/super.c
> @@ -433,12 +433,12 @@ static int f2fs_set_test_dummy_encryption(struct super_block *sb,
>  	 * needed to allow it to be set or changed during remount.  We do allow
>  	 * it to be specified during remount, but only if there is no change.
>  	 */
> -	if (is_remount && !F2FS_OPTION(sbi).dummy_enc_ctx.ctx) {
> +	if (is_remount && !F2FS_OPTION(sbi).dummy_enc_policy.policy) {
>  		f2fs_warn(sbi, "Can't set test_dummy_encryption on remount");
>  		return -EINVAL;
>  	}
>  	err = fscrypt_set_test_dummy_encryption(
> -		sb, arg, &F2FS_OPTION(sbi).dummy_enc_ctx);
> +		sb, arg, &F2FS_OPTION(sbi).dummy_enc_policy);
>  	if (err) {
>  		if (err == -EEXIST)
>  			f2fs_warn(sbi,
> @@ -1275,7 +1275,7 @@ static void f2fs_put_super(struct super_block *sb)
>  	for (i = 0; i < MAXQUOTAS; i++)
>  		kfree(F2FS_OPTION(sbi).s_qf_names[i]);
>  #endif
> -	fscrypt_free_dummy_context(&F2FS_OPTION(sbi).dummy_enc_ctx);
> +	fscrypt_free_dummy_policy(&F2FS_OPTION(sbi).dummy_enc_policy);
>  	destroy_percpu_info(sbi);
>  	for (i = 0; i < NR_PAGE_TYPE; i++)
>  		kvfree(sbi->write_io[i]);
> @@ -2482,10 +2482,10 @@ static int f2fs_set_context(struct inode *inode, const void *ctx, size_t len,
>  				ctx, len, fs_data, XATTR_CREATE);
>  }
>  
> -static const union fscrypt_context *
> -f2fs_get_dummy_context(struct super_block *sb)
> +static const union fscrypt_policy *
> +f2fs_get_dummy_policy(struct super_block *sb)
>  {
> -	return F2FS_OPTION(F2FS_SB(sb)).dummy_enc_ctx.ctx;
> +	return F2FS_OPTION(F2FS_SB(sb)).dummy_enc_policy.policy;
>  }
>  
>  static bool f2fs_has_stable_inodes(struct super_block *sb)
> @@ -2523,7 +2523,7 @@ static const struct fscrypt_operations f2fs_cryptops = {
>  	.key_prefix		= "f2fs:",
>  	.get_context		= f2fs_get_context,
>  	.set_context		= f2fs_set_context,
> -	.get_dummy_context	= f2fs_get_dummy_context,
> +	.get_dummy_policy	= f2fs_get_dummy_policy,
>  	.empty_dir		= f2fs_empty_dir,
>  	.max_namelen		= F2FS_NAME_LEN,
>  	.has_stable_inodes	= f2fs_has_stable_inodes,
> @@ -3864,7 +3864,7 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
>  	for (i = 0; i < MAXQUOTAS; i++)
>  		kfree(F2FS_OPTION(sbi).s_qf_names[i]);
>  #endif
> -	fscrypt_free_dummy_context(&F2FS_OPTION(sbi).dummy_enc_ctx);
> +	fscrypt_free_dummy_policy(&F2FS_OPTION(sbi).dummy_enc_policy);
>  	kvfree(options);
>  free_sb_buf:
>  	kfree(raw_super);
> diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h
> index 39e7397a3f103..b3b0c5675c6b1 100644
> --- a/include/linux/fscrypt.h
> +++ b/include/linux/fscrypt.h
> @@ -21,7 +21,7 @@
>  
>  #define FS_CRYPTO_BLOCK_SIZE		16
>  
> -union fscrypt_context;
> +union fscrypt_policy;
>  struct fscrypt_info;
>  struct seq_file;
>  
> @@ -62,8 +62,7 @@ struct fscrypt_operations {
>  	int (*get_context)(struct inode *inode, void *ctx, size_t len);
>  	int (*set_context)(struct inode *inode, const void *ctx, size_t len,
>  			   void *fs_data);
> -	const union fscrypt_context *(*get_dummy_context)(
> -		struct super_block *sb);
> +	const union fscrypt_policy *(*get_dummy_policy)(struct super_block *sb);
>  	bool (*empty_dir)(struct inode *inode);
>  	unsigned int max_namelen;
>  	bool (*has_stable_inodes)(struct super_block *sb);
> @@ -101,14 +100,6 @@ static inline bool fscrypt_needs_contents_encryption(const struct inode *inode)
>  	return IS_ENCRYPTED(inode) && S_ISREG(inode->i_mode);
>  }
>  
> -static inline const union fscrypt_context *
> -fscrypt_get_dummy_context(struct super_block *sb)
> -{
> -	if (!sb->s_cop->get_dummy_context)
> -		return NULL;
> -	return sb->s_cop->get_dummy_context(sb);
> -}
> -
>  /*
>   * When d_splice_alias() moves a directory's encrypted alias to its decrypted
>   * alias as a result of the encryption key being added, DCACHE_ENCRYPTED_NAME
> @@ -158,20 +149,21 @@ int fscrypt_ioctl_get_nonce(struct file *filp, void __user *arg);
>  int fscrypt_has_permitted_context(struct inode *parent, struct inode *child);
>  int fscrypt_set_context(struct inode *inode, void *fs_data);
>  
> -struct fscrypt_dummy_context {
> -	const union fscrypt_context *ctx;
> +struct fscrypt_dummy_policy {
> +	const union fscrypt_policy *policy;
>  };
>  
> -int fscrypt_set_test_dummy_encryption(struct super_block *sb,
> -				      const substring_t *arg,
> -				      struct fscrypt_dummy_context *dummy_ctx);
> +int fscrypt_set_test_dummy_encryption(
> +				struct super_block *sb,
> +				const substring_t *arg,
> +				struct fscrypt_dummy_policy *dummy_policy);
>  void fscrypt_show_test_dummy_encryption(struct seq_file *seq, char sep,
>  					struct super_block *sb);
>  static inline void
> -fscrypt_free_dummy_context(struct fscrypt_dummy_context *dummy_ctx)
> +fscrypt_free_dummy_policy(struct fscrypt_dummy_policy *dummy_policy)
>  {
> -	kfree(dummy_ctx->ctx);
> -	dummy_ctx->ctx = NULL;
> +	kfree(dummy_policy->policy);
> +	dummy_policy->policy = NULL;
>  }
>  
>  /* keyring.c */
> @@ -250,12 +242,6 @@ static inline bool fscrypt_needs_contents_encryption(const struct inode *inode)
>  	return false;
>  }
>  
> -static inline const union fscrypt_context *
> -fscrypt_get_dummy_context(struct super_block *sb)
> -{
> -	return NULL;
> -}
> -
>  static inline void fscrypt_handle_d_move(struct dentry *dentry)
>  {
>  }
> @@ -346,7 +332,7 @@ static inline int fscrypt_set_context(struct inode *inode, void *fs_data)
>  	return -EOPNOTSUPP;
>  }
>  
> -struct fscrypt_dummy_context {
> +struct fscrypt_dummy_policy {
>  };
>  
>  static inline void fscrypt_show_test_dummy_encryption(struct seq_file *seq,
> @@ -356,7 +342,7 @@ static inline void fscrypt_show_test_dummy_encryption(struct seq_file *seq,
>  }
>  
>  static inline void
> -fscrypt_free_dummy_context(struct fscrypt_dummy_context *dummy_ctx)
> +fscrypt_free_dummy_policy(struct fscrypt_dummy_policy *dummy_policy)
>  {
>  }
>  
> -- 
> 2.28.0
> 
> 
> 
> _______________________________________________
> Linux-f2fs-devel mailing list
> Linux-f2fs-devel@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel