From ec0caa974cd092549ab282deb8ec7ea73b36eba0 Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Wed, 2 Dec 2020 18:20:37 -0800 Subject: [PATCH] fscrypt: introduce fscrypt_prepare_readdir() The last remaining use of fscrypt_get_encryption_info() from filesystems is for readdir (->iterate_shared()). Every other call is now in fs/crypto/ as part of some other higher-level operation. We need to add a new argument to fscrypt_get_encryption_info() to indicate whether the encryption policy is allowed to be unrecognized or not. Doing this is easier if we can work with high-level operations rather than direct filesystem use of fscrypt_get_encryption_info(). So add a function fscrypt_prepare_readdir() which wraps the call to fscrypt_get_encryption_info() for the readdir use case. Reviewed-by: Andreas Dilger Link: https://lore.kernel.org/r/20201203022041.230976-6-ebiggers@kernel.org Signed-off-by: Eric Biggers --- fs/crypto/hooks.c | 6 ++++++ fs/ext4/dir.c | 8 +++----- fs/ext4/namei.c | 2 +- fs/f2fs/dir.c | 2 +- fs/ubifs/dir.c | 2 +- include/linux/fscrypt.h | 24 ++++++++++++++++++++++++ 6 files changed, 36 insertions(+), 8 deletions(-) diff --git a/fs/crypto/hooks.c b/fs/crypto/hooks.c index c809a4afa057..82f351d3113a 100644 --- a/fs/crypto/hooks.c +++ b/fs/crypto/hooks.c @@ -114,6 +114,12 @@ int __fscrypt_prepare_lookup(struct inode *dir, struct dentry *dentry, } EXPORT_SYMBOL_GPL(__fscrypt_prepare_lookup); +int __fscrypt_prepare_readdir(struct inode *dir) +{ + return fscrypt_get_encryption_info(dir); +} +EXPORT_SYMBOL_GPL(__fscrypt_prepare_readdir); + /** * fscrypt_prepare_setflags() - prepare to change flags with FS_IOC_SETFLAGS * @inode: the inode on which flags are being changed diff --git a/fs/ext4/dir.c b/fs/ext4/dir.c index 16bfbdd5007c..c6d16353326a 100644 --- a/fs/ext4/dir.c +++ b/fs/ext4/dir.c @@ -118,11 +118,9 @@ static int ext4_readdir(struct file *file, struct dir_context *ctx) struct buffer_head *bh = NULL; struct fscrypt_str fstr = FSTR_INIT(NULL, 0); - if (IS_ENCRYPTED(inode)) { - err = fscrypt_get_encryption_info(inode); - if (err) - return err; - } + err = fscrypt_prepare_readdir(inode); + if (err) + return err; if (is_dx_dir(inode)) { err = ext4_dx_readdir(file, ctx); diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c index 7b31aea3e025..5fa8436cd5fa 100644 --- a/fs/ext4/namei.c +++ b/fs/ext4/namei.c @@ -1004,7 +1004,7 @@ static int htree_dirblock_to_tree(struct file *dir_file, EXT4_DIR_REC_LEN(0)); /* Check if the directory is encrypted */ if (IS_ENCRYPTED(dir)) { - err = fscrypt_get_encryption_info(dir); + err = fscrypt_prepare_readdir(dir); if (err < 0) { brelse(bh); return err; diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c index 47bee953fc8d..049500f1e764 100644 --- a/fs/f2fs/dir.c +++ b/fs/f2fs/dir.c @@ -1022,7 +1022,7 @@ static int f2fs_readdir(struct file *file, struct dir_context *ctx) int err = 0; if (IS_ENCRYPTED(inode)) { - err = fscrypt_get_encryption_info(inode); + err = fscrypt_prepare_readdir(inode); if (err) goto out; diff --git a/fs/ubifs/dir.c b/fs/ubifs/dir.c index 009fbf844d3e..1f33a5598b93 100644 --- a/fs/ubifs/dir.c +++ b/fs/ubifs/dir.c @@ -514,7 +514,7 @@ static int ubifs_readdir(struct file *file, struct dir_context *ctx) return 0; if (encrypted) { - err = fscrypt_get_encryption_info(dir); + err = fscrypt_prepare_readdir(dir); if (err) return err; diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h index 0c9e64969b73..8cbb26f55695 100644 --- a/include/linux/fscrypt.h +++ b/include/linux/fscrypt.h @@ -242,6 +242,7 @@ int __fscrypt_prepare_rename(struct inode *old_dir, struct dentry *old_dentry, unsigned int flags); int __fscrypt_prepare_lookup(struct inode *dir, struct dentry *dentry, struct fscrypt_name *fname); +int __fscrypt_prepare_readdir(struct inode *dir); int fscrypt_prepare_setflags(struct inode *inode, unsigned int oldflags, unsigned int flags); int fscrypt_prepare_symlink(struct inode *dir, const char *target, @@ -537,6 +538,11 @@ static inline int __fscrypt_prepare_lookup(struct inode *dir, return -EOPNOTSUPP; } +static inline int __fscrypt_prepare_readdir(struct inode *dir) +{ + return -EOPNOTSUPP; +} + static inline int fscrypt_prepare_setflags(struct inode *inode, unsigned int oldflags, unsigned int flags) @@ -795,6 +801,24 @@ static inline int fscrypt_prepare_lookup(struct inode *dir, return 0; } +/** + * fscrypt_prepare_readdir() - prepare to read a possibly-encrypted directory + * @dir: the directory inode + * + * If the directory is encrypted and it doesn't already have its encryption key + * set up, try to set it up so that the filenames will be listed in plaintext + * form rather than in no-key form. + * + * Return: 0 on success; -errno on error. Note that the encryption key being + * unavailable is not considered an error. + */ +static inline int fscrypt_prepare_readdir(struct inode *dir) +{ + if (IS_ENCRYPTED(dir)) + return __fscrypt_prepare_readdir(dir); + return 0; +} + /** * fscrypt_prepare_setattr() - prepare to change a possibly-encrypted inode's * attributes