[PATCH v2 4/5] f2fs: consolidate fscrypt_has_permitted_context() checks

[Eric Biggers <ebiggers3@gmail.com>]

From: Eric Biggers <ebiggers@google.com>

This ports the changes from the corresponding ext4 patch to f2fs.

This patch should not be applied before my other two patches:

    fscrypt: fix loophole in one-encryption-policy-per-tree enforcement
    fscrypt: fix renaming and linking special files

Signed-off-by: Eric Biggers <ebiggers@google.com>
---
 fs/f2fs/file.c  | 15 +++++----------
 fs/f2fs/namei.c |  7 ++-----
 2 files changed, 7 insertions(+), 15 deletions(-)

diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 49f10dc..381d39b 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -443,23 +443,18 @@ static int f2fs_file_mmap(struct file *file, struct vm_area_struct *vma)
 static int f2fs_file_open(struct inode *inode, struct file *filp)
 {
 	int ret = generic_file_open(inode, filp);
-	struct dentry *dir;
 
-	if (!ret && f2fs_encrypted_inode(inode)) {
+	if (ret)
+		return ret;
+
+	if (f2fs_encrypted_inode(inode)) {
 		ret = fscrypt_get_encryption_info(inode);
 		if (ret)
 			return -EACCES;
 		if (!fscrypt_has_encryption_key(inode))
 			return -ENOKEY;
 	}
-	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;
+	return 0;
 }
 
 int truncate_data_blocks_range(struct dnode_of_data *dn, int count)
diff --git a/fs/f2fs/namei.c b/fs/f2fs/namei.c
index 56c19b0..53ff18f 100644
--- a/fs/f2fs/namei.c
+++ b/fs/f2fs/namei.c
@@ -322,11 +322,8 @@ static struct dentry *f2fs_lookup(struct inode *dir, struct dentry *dentry,
 			goto err_out;
 	}
 	if (!IS_ERR(inode) && f2fs_encrypted_inode(dir) &&
-			(S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode)) &&
-			!fscrypt_has_permitted_context(dir, inode)) {
-		bool nokey = f2fs_encrypted_inode(inode) &&
-			!fscrypt_has_encryption_key(inode);
-		err = nokey ? -ENOKEY : -EPERM;
+	    !fscrypt_has_permitted_context(dir, inode)) {
+		err = -EPERM;
 		goto err_out;
 	}
 	return d_splice_alias(inode, dentry);
-- 
2.8.0.rc3.226.g39d4020