ceph: make ceph_fill_trace and ceph_get_name decrypt names

When we get a dentry in a trace, decrypt the name so we can properly
instantiate the dentry or fill out ceph_get_name() buffer.

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>

Author: jtlayton

fs/ceph/export.c

@@ -7,6 +7,7 @@
 
 #include "super.h"
 #include "mds_client.h"
+#include "crypto.h"
 
 /*
  * Basic fh
@@ -535,7 +536,9 @@ static int ceph_get_name(struct dentry *parent, char *name,
 {
 	struct ceph_mds_client *mdsc;
 	struct ceph_mds_request *req;
+	struct inode *dir = d_inode(parent);
 	struct inode *inode = d_inode(child);
+	struct ceph_mds_reply_info_parsed *rinfo;
 	int err;
 
 	if (ceph_snap(inode) != CEPH_NOSNAP)
@@ -547,30 +550,47 @@ static int ceph_get_name(struct dentry *parent, char *name,
 	if (IS_ERR(req))
 		return PTR_ERR(req);
 
-	inode_lock(d_inode(parent));
-
+	inode_lock(dir);
 	req->r_inode = inode;
 	ihold(inode);
 	req->r_ino2 = ceph_vino(d_inode(parent));
-	req->r_parent = d_inode(parent);
-	ihold(req->r_parent);
+	req->r_parent = dir;
+	ihold(dir);
 	set_bit(CEPH_MDS_R_PARENT_LOCKED, &req->r_req_flags);
 	req->r_num_caps = 2;
 	err = ceph_mdsc_do_request(mdsc, NULL, req);
+	inode_unlock(dir);
 
-	inode_unlock(d_inode(parent));
+	if (err)
+		goto out;
 
-	if (!err) {
-		struct ceph_mds_reply_info_parsed *rinfo = &req->r_reply_info;
+	rinfo = &req->r_reply_info;
+	if (!IS_ENCRYPTED(dir)) {
 		memcpy(name, rinfo->dname, rinfo->dname_len);
 		name[rinfo->dname_len] = 0;
-		dout("get_name %p ino %llx.%llx name %s\n",
-		     child, ceph_vinop(inode), name);
 	} else {
-		dout("get_name %p ino %llx.%llx err %d\n",
-		     child, ceph_vinop(inode), err);
-	}
+		struct fscrypt_str oname = FSTR_INIT(NULL, 0);
+		struct ceph_fname fname = { .dir	= dir,
+					    .name	= rinfo->dname,
+					    .ctext	= rinfo->altname,
+					    .name_len	= rinfo->dname_len,
+					    .ctext_len	= rinfo->altname_len };
+
+		err = ceph_fname_alloc_buffer(dir, &oname);
+		if (err < 0)
+			goto out;
 
+		err = ceph_fname_to_usr(&fname, NULL, &oname, NULL);
+		if (!err) {
+			memcpy(name, oname.name, oname.len);
+			name[oname.len] = 0;
+		}
+		ceph_fname_free_buffer(dir, &oname);
+	}
+out:
+	dout("get_name %p ino %llx.%llx err %d %s%s\n",
+		     child, ceph_vinop(inode), err,
+		     err ? "" : "name ", err ? "" : name);
 	ceph_mdsc_put_request(req);
 	return err;
 }

fs/ceph/inode.c

@@ -1406,17 +1406,36 @@ int ceph_fill_trace(struct super_block *sb, struct ceph_mds_request *req)
 		if (dir && req->r_op == CEPH_MDS_OP_LOOKUPNAME &&
 		    test_bit(CEPH_MDS_R_PARENT_LOCKED, &req->r_req_flags) &&
 		    !test_bit(CEPH_MDS_R_ABORTED, &req->r_req_flags)) {
+			bool is_nokey = false;
 			struct qstr dname;
 			struct dentry *dn, *parent;
+			struct fscrypt_str oname = FSTR_INIT(NULL, 0);
+			struct ceph_fname fname = { .dir	= dir,
+						    .name	= rinfo->dname,
+						    .ctext	= rinfo->altname,
+						    .name_len	= rinfo->dname_len,
+						    .ctext_len	= rinfo->altname_len };
 
 			BUG_ON(!rinfo->head->is_target);
 			BUG_ON(req->r_dentry);
 
 			parent = d_find_any_alias(dir);
 			BUG_ON(!parent);
 
-			dname.name = rinfo->dname;
-			dname.len = rinfo->dname_len;
+			err = ceph_fname_alloc_buffer(dir, &oname);
+			if (err < 0) {
+				dput(parent);
+				goto done;
+			}
+
+			err = ceph_fname_to_usr(&fname, NULL, &oname, &is_nokey);
+			if (err < 0) {
+				dput(parent);
+				ceph_fname_free_buffer(dir, &oname);
+				goto done;
+			}
+			dname.name = oname.name;
+			dname.len = oname.len;
 			dname.hash = full_name_hash(parent, dname.name, dname.len);
 			tvino.ino = le64_to_cpu(rinfo->targeti.in->ino);
 			tvino.snap = le64_to_cpu(rinfo->targeti.in->snapid);
@@ -1431,9 +1450,15 @@ int ceph_fill_trace(struct super_block *sb, struct ceph_mds_request *req)
 				     dname.len, dname.name, dn);
 				if (!dn) {
 					dput(parent);
+					ceph_fname_free_buffer(dir, &oname);
 					err = -ENOMEM;
 					goto done;
 				}
+				if (is_nokey) {
+					spin_lock(&dn->d_lock);
+					dn->d_flags |= DCACHE_NOKEY_NAME;
+					spin_unlock(&dn->d_lock);
+				}
 				err = 0;
 			} else if (d_really_is_positive(dn) &&
 				   (ceph_ino(d_inode(dn)) != tvino.ino ||
@@ -1445,6 +1470,7 @@ int ceph_fill_trace(struct super_block *sb, struct ceph_mds_request *req)
 				dput(dn);
 				goto retry_lookup;
 			}
+			ceph_fname_free_buffer(dir, &oname);
 
 			req->r_dentry = dn;
 			dput(parent);