f2fs crypto: activate encryption support for fs APIs

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)
10. f2fs_fallocate        : do not support fcollapse
11. f2fs_evict_inode      : free_encryption_info

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>

1 files changed, 39 insertions, 2 deletions

diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index a66970d99cb4..9eb0100c57fd 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 +426,18 @@ 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)
+{
+        int ret = generic_file_open(inode, filp);
+
+        if (!ret && f2fs_encrypted_inode(inode)) {
+                ret = f2fs_get_encryption_info(inode);
+                if (ret)
+                        ret = -EACCES;
+        }
+        return ret;
+}
+
 int truncate_data_blocks_range(struct dnode_of_data *dn, int count)
 {
         int nr_free = 0, ofs = dn->ofs_in_node;
@@ -627,6 +645,10 @@ 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);
@@ -1061,6 +1083,9 @@ static long f2fs_fallocate(struct file *file, int mode,
         struct inode *inode = file_inode(file);
         long ret = 0;
 
+        if (f2fs_encrypted_inode(inode) && (mode & FALLOC_FL_COLLAPSE_RANGE))
+                return -EOPNOTSUPP;
+
         if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE |
                         FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_ZERO_RANGE))
                 return -EOPNOTSUPP;
@@ -1468,6 +1493,18 @@ 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)
 {
@@ -1488,8 +1525,8 @@ 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,