ceph: encode encrypted name in ceph_mdsc_build_path and dentry release

Allow ceph_mdsc_build_path to encrypt and base64 encode the filename
when the parent is encrypted and we're sending the path to the MDS. In
a similar fashion, encode encrypted dentry names if including a dentry
release in a request.

In most cases, we just encrypt the filenames and base64 encode them,
but when the name is longer than CEPH_NOHASH_NAME_MAX, we use a similar
scheme to fscrypt proper, and hash the remaning bits with sha256.

When doing this, we then send along the full crypttext of the name in
the new alternate_name field of the MClientRequest. The MDS can then
send that along in readdir responses and traces.

[ idryomov: drop duplicate include reported by Abaci Robot ]

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Xiubo Li <xiubli@redhat.com>
Reviewed-and-tested-by: Luís Henriques <lhenriques@suse.de>
Reviewed-by: Milind Changire <mchangir@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

1 files changed, 28 insertions, 4 deletions

diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
index 1c62ef339bc6..4738be54dc73 100644
--- a/fs/ceph/caps.c
+++ b/fs/ceph/caps.c
@@ -4663,6 +4663,18 @@ int ceph_encode_inode_release(void **p, struct inode *inode,
 	return ret;
 }
 
+/**
+ * ceph_encode_dentry_release - encode a dentry release into an outgoing request
+ * @p: outgoing request buffer
+ * @dentry: dentry to release
+ * @dir: dir to release it from
+ * @mds: mds that we're speaking to
+ * @drop: caps being dropped
+ * @unless: unless we have these caps
+ *
+ * Encode a dentry release into an outgoing request buffer. Returns 1 if the
+ * thing was released, or a negative error code otherwise.
+ */
 int ceph_encode_dentry_release(void **p, struct dentry *dentry,
 			       struct inode *dir,
 			       int mds, int drop, int unless)
@@ -4695,13 +4707,25 @@ int ceph_encode_dentry_release(void **p, struct dentry *dentry,
 	if (ret && di->lease_session && di->lease_session->s_mds == mds) {
 		dout("encode_dentry_release %p mds%d seq %d\n",
 		     dentry, mds, (int)di->lease_seq);
-		rel->dname_len = cpu_to_le32(dentry->d_name.len);
-		memcpy(*p, dentry->d_name.name, dentry->d_name.len);
-		*p += dentry->d_name.len;
 		rel->dname_seq = cpu_to_le32(di->lease_seq);
 		__ceph_mdsc_drop_dentry_lease(dentry);
+		spin_unlock(&dentry->d_lock);
+		if (IS_ENCRYPTED(dir) && fscrypt_has_encryption_key(dir)) {
+			int ret2 = ceph_encode_encrypted_fname(dir, dentry, *p);
+
+			if (ret2 < 0)
+				return ret2;
+
+			rel->dname_len = cpu_to_le32(ret2);
+			*p += ret2;
+		} else {
+			rel->dname_len = cpu_to_le32(dentry->d_name.len);
+			memcpy(*p, dentry->d_name.name, dentry->d_name.len);
+			*p += dentry->d_name.len;
+		}
+	} else {
+		spin_unlock(&dentry->d_lock);
 	}
-	spin_unlock(&dentry->d_lock);
 	return ret;
 }