f2fs: use dget_parent and file_dentry in f2fs_file_open
This patch synced with the below two ext4 crypto fixes together.
In 4.6-rc1, f2fs newly introduced accessing f_path.dentry which crashes
overlayfs. To fix, now we need to use file_dentry() to access that field.
Fixes: c0a37d487884 ("ext4: use file_dentry()")
Fixes: 9dd78d8c9a7b ("ext4: use dget_parent() in ext4_file_open()")
Cc: Miklos Szeredi <mszeredi@redhat.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 443e077..90d1157 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -441,7 +441,7 @@
static int f2fs_file_open(struct inode *inode, struct file *filp)
{
int ret = generic_file_open(inode, filp);
- struct inode *dir = filp->f_path.dentry->d_parent->d_inode;
+ struct dentry *dir;
if (!ret && f2fs_encrypted_inode(inode)) {
ret = fscrypt_get_encryption_info(inode);
@@ -450,9 +450,13 @@
if (!fscrypt_has_encryption_key(inode))
return -ENOKEY;
}
- if (f2fs_encrypted_inode(dir) &&
- !fscrypt_has_permitted_context(dir, inode))
+ dir = dget_parent(file_dentry(filp));
+ if (f2fs_encrypted_inode(d_inode(dir)) &&
+ !fscrypt_has_permitted_context(d_inode(dir), inode)) {
+ dput(dir);
return -EPERM;
+ }
+ dput(dir);
return ret;
}