linux-ext4 - [PATCH] ext4: don't allow encrypted operations without keys

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Message-Id: <20161228052252.10314-1-tytso@mit.edu>
Date:   Wed, 28 Dec 2016 00:22:52 -0500
From:   Theodore Ts'o <tytso@....edu>
To:     Ext4 Developers List <linux-ext4@...r.kernel.org>
Cc:     Linux Filesystem Development List <linux-fsdevel@...r.kernel.org>,
        jaegeuk@...nel.org, richard@....at, ebiggers@...gle.com,
        Theodore Ts'o <tytso@....edu>
Subject: [PATCH] ext4: don't allow encrypted operations without keys

While we allow deletes without the key, the following should not be
permitted:

# cd /vdc/encrypted-dir-without-key
# ls -l
total 4
-rw-r--r-- 1 root root   0 Dec 27 22:35 6,LKNRJsp209FbXoSvJWzB
-rw-r--r-- 1 root root 286 Dec 27 22:35 uRJ5vJh9gE7vcomYMqTAyD
# mv uRJ5vJh9gE7vcomYMqTAyD  6,LKNRJsp209FbXoSvJWzB

Signed-off-by: Theodore Ts'o <tytso@....edu>
---
 fs/ext4/namei.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index eadba919f26b..45a5ba558074 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -3525,6 +3525,12 @@ static int ext4_rename(struct inode *old_dir, struct dentry *old_dentry,
 			EXT4_I(old_dentry->d_inode)->i_projid)))
 		return -EXDEV;
 
+	if ((ext4_encrypted_inode(old_dir) &&
+	     !fscrypt_has_encryption_key(old_dir)) ||
+	    (ext4_encrypted_inode(new_dir) &&
+	     !fscrypt_has_encryption_key(new_dir)))
+		return -ENOKEY;
+
 	retval = dquot_initialize(old.dir);
 	if (retval)
 		return retval;
@@ -3725,6 +3731,12 @@ static int ext4_cross_rename(struct inode *old_dir, struct dentry *old_dentry,
 	int retval;
 	struct timespec ctime;
 
+	if ((ext4_encrypted_inode(old_dir) &&
+	     !fscrypt_has_encryption_key(old_dir)) ||
+	    (ext4_encrypted_inode(new_dir) &&
+	     !fscrypt_has_encryption_key(new_dir)))
+		return -ENOKEY;
+
 	if ((ext4_encrypted_inode(old_dir) ||
 	     ext4_encrypted_inode(new_dir)) &&
 	    (old_dir != new_dir) &&
-- 
2.11.0.rc0.7.gbe5a750

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