From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Biggers Subject: [PATCH 09/25] fscrypt: new helper function - fscrypt_prepare_lookup() Date: Wed, 20 Sep 2017 15:45:49 -0700 Message-ID: <20170920224605.22030-10-ebiggers3@gmail.com> References: <20170920224605.22030-1-ebiggers3@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from sog-mx-4.v43.ch3.sourceforge.com ([172.29.43.194] helo=mx.sourceforge.net) by sfs-ml-1.v29.ch3.sourceforge.com with esmtps (TLSv1:DHE-RSA-AES256-SHA:256) (Exim 4.89) (envelope-from ) id 1dunlr-0003lP-UK for linux-f2fs-devel@lists.sourceforge.net; Wed, 20 Sep 2017 22:47:07 +0000 Received: from mail-pg0-f66.google.com ([74.125.83.66]) by sog-mx-4.v43.ch3.sourceforge.com with esmtps (TLSv1:AES128-SHA:128) (Exim 4.76) id 1dunlr-0003CG-1M for linux-f2fs-devel@lists.sourceforge.net; Wed, 20 Sep 2017 22:47:07 +0000 Received: by mail-pg0-f66.google.com with SMTP id v5so2365336pgn.4 for ; Wed, 20 Sep 2017 15:47:07 -0700 (PDT) In-Reply-To: <20170920224605.22030-1-ebiggers3@gmail.com> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: linux-f2fs-devel-bounces@lists.sourceforge.net To: linux-fscrypt@vger.kernel.org Cc: "Theodore Y . Ts'o" , Eric Biggers , Michael Halcrow , linux-f2fs-devel@lists.sourceforge.net, linux-mtd@lists.infradead.org, linux-fsdevel@vger.kernel.org, Jaegeuk Kim , linux-ext4@vger.kernel.org From: Eric Biggers Introduce a helper function which prepares to look up the given dentry in the given directory. If the directory is encrypted, it handles loading the directory's encryption key, setting the dentry's ->d_op to fscrypt_d_ops, and setting DCACHE_ENCRYPTED_WITH_KEY if the directory's encryption key is available. Note: once all filesystems switch over to this, we'll be able to move fscrypt_d_ops and fscrypt_set_encrypted_dentry() to fscrypt_private.h. Signed-off-by: Eric Biggers --- fs/crypto/hooks.c | 18 ++++++++++++++++++ include/linux/fscrypt_notsupp.h | 9 +++++++++ include/linux/fscrypt_supp.h | 30 ++++++++++++++++++++++++++++++ 3 files changed, 57 insertions(+) diff --git a/fs/crypto/hooks.c b/fs/crypto/hooks.c index 822cb78f9b45..9f5fb2eb9cf7 100644 --- a/fs/crypto/hooks.c +++ b/fs/crypto/hooks.c @@ -92,3 +92,21 @@ int __fscrypt_prepare_rename(struct inode *old_dir, struct dentry *old_dentry, return 0; } EXPORT_SYMBOL_GPL(__fscrypt_prepare_rename); + +int __fscrypt_prepare_lookup(struct inode *dir, struct dentry *dentry) +{ + int err = fscrypt_get_encryption_info(dir); + + if (err) + return err; + + if (fscrypt_has_encryption_key(dir)) { + spin_lock(&dentry->d_lock); + dentry->d_flags |= DCACHE_ENCRYPTED_WITH_KEY; + spin_unlock(&dentry->d_lock); + } + + d_set_d_op(dentry, &fscrypt_d_ops); + return 0; +} +EXPORT_SYMBOL_GPL(__fscrypt_prepare_lookup); diff --git a/include/linux/fscrypt_notsupp.h b/include/linux/fscrypt_notsupp.h index a88a2959cd8c..e9b437605f9c 100644 --- a/include/linux/fscrypt_notsupp.h +++ b/include/linux/fscrypt_notsupp.h @@ -209,4 +209,13 @@ static inline int fscrypt_prepare_rename(struct inode *old_dir, return 0; } +static inline int fscrypt_prepare_lookup(struct inode *dir, + struct dentry *dentry, + unsigned int flags) +{ + if (IS_ENCRYPTED(dir)) + return -EOPNOTSUPP; + return 0; +} + #endif /* _LINUX_FSCRYPT_NOTSUPP_H */ diff --git a/include/linux/fscrypt_supp.h b/include/linux/fscrypt_supp.h index fa062d41b39a..2b99bc01c59b 100644 --- a/include/linux/fscrypt_supp.h +++ b/include/linux/fscrypt_supp.h @@ -240,4 +240,34 @@ static inline int fscrypt_prepare_rename(struct inode *old_dir, return 0; } +extern int __fscrypt_prepare_lookup(struct inode *dir, struct dentry *dentry); + +/** + * fscrypt_prepare_lookup - prepare to lookup a name in a possibly-encrypted directory + * @dir: directory being searched + * @dentry: filename being looked up + * @flags: lookup flags + * + * Prepare for ->lookup() in a directory which may be encrypted. Lookups can be + * done with or without the directory's encryption key; without the key, + * filenames are presented in encrypted form. Therefore, we'll try to set up + * the directory's encryption key, but even without it the lookup can continue. + * + * To allow invalidating stale dentries if the directory's encryption key is + * added later, we also install a custom ->d_revalidate() method and use the + * DCACHE_ENCRYPTED_WITH_KEY flag to indicate whether a given dentry is a + * plaintext name (flag set) or a ciphertext name (flag cleared). + * + * Return: 0 on success, -errno if a problem occurred while setting up the + * encryption key + */ +static inline int fscrypt_prepare_lookup(struct inode *dir, + struct dentry *dentry, + unsigned int flags) +{ + if (IS_ENCRYPTED(dir)) + return __fscrypt_prepare_lookup(dir, dentry); + return 0; +} + #endif /* _LINUX_FSCRYPT_SUPP_H */ -- 2.14.1.821.g8fa685d3b7-goog ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot