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Message-Id: <20201125002336.274045-6-ebiggers@kernel.org>
Date: Tue, 24 Nov 2020 16:23:32 -0800
From: Eric Biggers <ebiggers@...nel.org>
To: linux-fscrypt@...r.kernel.org
Cc: linux-ext4@...r.kernel.org, linux-f2fs-devel@...ts.sourceforge.net,
linux-mtd@...ts.infradead.org, linux-fsdevel@...r.kernel.org
Subject: [PATCH 5/9] fscrypt: introduce fscrypt_prepare_readdir()
From: Eric Biggers <ebiggers@...gle.com>
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 to 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.
Signed-off-by: Eric Biggers <ebiggers@...gle.com>
---
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
--
2.29.2
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