[PATCH 10/18] f2fs crypto: activate encryption support for fs APIs

Jaegeuk Kim
2015-05-09T04:24:35Z

This patch activates the following APIs for encryption support.

The rules quoted by ext4 are:
- An unencrypted directory may contain encrypted or unencrypted files
or directories.
- All files or directories in a directory must be protected using the
same key as their containing directory.
- Encrypted inode for regular file should not have inline_data.
- Encrypted symlink and directory may have inline_data and inline_dentry.

This patch activates the following APIs.
1. f2fs_link : validate context
2. f2fs_lookup : ''
3. f2fs_rename : ''
4. f2fs_create/f2fs_mkdir : inherit its dir's context
5. f2fs_direct_IO : do buffered io for regular files
6. f2fs_open : check encryption info
7. f2fs_file_mmap : ''
8. f2fs_setattr : ''
9. f2fs_file_write_iter : '' (Called by sys_io_submit)

Signed-off-by: Michael Halcrow <mhalcrow@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
---
fs/f2fs/data.c | 3 +++
fs/f2fs/dir.c | 6 ++++++
fs/f2fs/f2fs.h | 11 +++++++++++
fs/f2fs/file.c | 34 ++++++++++++++++++++++++++++++++--
fs/f2fs/inline.c | 3 +++
fs/f2fs/namei.c | 38 ++++++++++++++++++++++++++++++++------
6 files changed, 87 insertions(+), 8 deletions(-)

diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 842fcdd..473b4d4 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -1982,6 +1982,9 @@ static ssize_t f2fs_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
return err;
}

+ if (f2fs_encrypted_inode(inode) && S_ISREG(inode->i_mode))
+ return 0;
+
if (check_direct_IO(inode, iter, offset))
return 0;

diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c
index 9d558d2..f7293a2 100644
--- a/fs/f2fs/dir.c
+++ b/fs/f2fs/dir.c
@@ -390,6 +390,12 @@ struct page *init_inode_metadata(struct inode *inode, struct inode *dir,
err = f2fs_init_security(inode, dir, name, page);
if (err)
goto put_error;
+
+ if (f2fs_encrypted_inode(dir) && f2fs_may_encrypt(inode)) {
+ err = f2fs_inherit_context(dir, inode, page);
+ if (err)
+ goto put_error;
+ }
} else {
page = get_node_page(F2FS_I_SB(dir), inode->i_ino);
if (IS_ERR(page))
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index e99205b..544766e 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -1975,6 +1975,17 @@ static inline int f2fs_sb_has_crypto(struct super_block *sb)
#endif
}

+static inline bool f2fs_may_encrypt(struct inode *inode)
+{
+#ifdef CONFIG_F2FS_FS_ENCRYPTION
+ mode_t mode = inode->i_mode;
+
+ return (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode));
+#else
+ return 0;
+#endif
+}
+
/* crypto_policy.c */
int f2fs_is_child_context_consistent_with_parent(struct inode *,
struct inode *);
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 7236be4..9f4b34c 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -408,6 +408,12 @@ static int f2fs_file_mmap(struct file *file, struct vm_area_struct *vma)
{
struct inode *inode = file_inode(file);

+ if (f2fs_encrypted_inode(inode)) {
+ int err = f2fs_get_encryption_info(inode);
+ if (err)
+ return 0;
+ }
+
/* we don't need to use inline_data strictly */
if (f2fs_has_inline_data(inode)) {
int err = f2fs_convert_inline_inode(inode);
@@ -420,6 +426,14 @@ static int f2fs_file_mmap(struct file *file, struct vm_area_struct *vma)
return 0;
}

+static int f2fs_file_open(struct inode *inode, struct file *filp)
+{
+ if (f2fs_encrypted_inode(inode) && f2fs_get_encryption_info(inode))
+ return -EACCES;
+
+ return generic_file_open(inode, filp);
+}
+
int truncate_data_blocks_range(struct dnode_of_data *dn, int count)
{
int nr_free = 0, ofs = dn->ofs_in_node;
@@ -627,6 +641,10 @@ int f2fs_setattr(struct dentry *dentry, struct iattr *attr)
return err;

if (attr->ia_valid & ATTR_SIZE) {
+ if (f2fs_encrypted_inode(inode) &&
+ f2fs_get_encryption_info(inode))
+ return -EACCES;
+
if (attr->ia_size != i_size_read(inode)) {
truncate_setsize(inode, attr->ia_size);
f2fs_truncate(inode);
@@ -1466,6 +1484,18 @@ long f2fs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
}
}

+static ssize_t f2fs_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
+{
+ struct inode *inode = file_inode(iocb->ki_filp);
+
+ if (f2fs_encrypted_inode(inode) &&
+ !f2fs_has_encryption_key(inode) &&
+ f2fs_get_encryption_info(inode))
+ return -EACCES;
+
+ return generic_file_write_iter(iocb, from);
+}
+
#ifdef CONFIG_COMPAT
long f2fs_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
@@ -1486,8 +1516,8 @@ long f2fs_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
const struct file_operations f2fs_file_operations = {
.llseek = f2fs_llseek,
.read_iter = generic_file_read_iter,
- .write_iter = generic_file_write_iter,
- .open = generic_file_open,
+ .write_iter = f2fs_file_write_iter,
+ .open = f2fs_file_open,
.release = f2fs_release_file,
.mmap = f2fs_file_mmap,
.fsync = f2fs_sync_file,
diff --git a/fs/f2fs/inline.c b/fs/f2fs/inline.c
index d9b3033..5f5b34b 100644
--- a/fs/f2fs/inline.c
+++ b/fs/f2fs/inline.c
@@ -27,6 +27,9 @@ bool f2fs_may_inline_data(struct inode *inode)
if (i_size_read(inode) > MAX_INLINE_DATA)
return false;

+ if (f2fs_encrypted_inode(inode) && S_ISREG(inode->i_mode))
+ return false;
+
return true;
}

diff --git a/fs/f2fs/namei.c b/fs/f2fs/namei.c
index 90a9640..bc8992e 100644
--- a/fs/f2fs/namei.c
+++ b/fs/f2fs/namei.c
@@ -56,6 +56,10 @@ static struct inode *f2fs_new_inode(struct inode *dir, umode_t mode)
goto out;
}

+ /* If the directory encrypted, then we should encrypt the inode. */
+ if (f2fs_encrypted_inode(dir) && f2fs_may_encrypt(inode))
+ f2fs_set_encrypted_inode(inode);
+
if (f2fs_may_inline_data(inode))
set_inode_flag(F2FS_I(inode), FI_INLINE_DATA);
if (f2fs_may_inline_dentry(inode))
@@ -157,6 +161,10 @@ static int f2fs_link(struct dentry *old_dentry, struct inode *dir,
struct f2fs_sb_info *sbi = F2FS_I_SB(dir);
int err;

+ if (f2fs_encrypted_inode(dir) &&
+ !f2fs_is_child_context_consistent_with_parent(dir, inode))
+ return -EPERM;
+
f2fs_balance_fs(sbi);

inode->i_ctime = CURRENT_TIME;
@@ -235,6 +243,7 @@ static struct dentry *f2fs_lookup(struct inode *dir, struct dentry *dentry,
struct f2fs_dir_entry *de;
struct page *page;
nid_t ino;
+ int err = 0;

if (dentry->d_name.len > F2FS_NAME_LEN)
return ERR_PTR(-ENAMETOOLONG);
@@ -251,16 +260,26 @@ static struct dentry *f2fs_lookup(struct inode *dir, struct dentry *dentry,
if (IS_ERR(inode))
return ERR_CAST(inode);

- if (f2fs_has_inline_dots(inode)) {
- int err;
+ if (f2fs_encrypted_inode(dir) && f2fs_may_encrypt(inode) &&
+ !f2fs_is_child_context_consistent_with_parent(dir, inode)) {
+ iput(inode);
+ f2fs_msg(inode->i_sb, KERN_WARNING,
+ "Inconsistent encryption contexts: %lu/%lu\n",
+ (unsigned long)dir->i_ino,
+ (unsigned long)inode->i_ino);
+ return ERR_PTR(-EPERM);
+ }

+ if (f2fs_has_inline_dots(inode)) {
err = __recover_dot_dentries(inode, dir->i_ino);
- if (err) {
- iget_failed(inode);
- return ERR_PTR(err);
- }
+ if (err)
+ goto err_out;
}
return d_splice_alias(inode, dentry);
+
+err_out:
+ iget_failed(inode);
+ return ERR_PTR(err);
}

static int f2fs_unlink(struct inode *dir, struct dentry *dentry)
@@ -460,6 +479,13 @@ static int f2fs_rename(struct inode *old_dir, struct dentry *old_dentry,
struct f2fs_dir_entry *new_entry;
int err = -ENOENT;

+ if ((old_dir != new_dir) && f2fs_encrypted_inode(new_dir) &&
+ !f2fs_is_child_context_consistent_with_parent(new_dir,
+ old_inode)) {
+ err = -EPERM;
+ goto out;
+ }
+
f2fs_balance_fs(sbi);

old_entry = f2fs_find_entry(old_dir, &old_dentry->d_name, &old_page);
--
2.1.1