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From: Jeff Layton <jlayton@kernel.org>
To: ceph-devel@vger.kernel.org, linux-fscrypt@vger.kernel.org
Cc: linux-fsdevel@vger.kernel.org
Subject: [RFC PATCH v3 12/16] ceph: add encrypted fname handling to ceph_mdsc_build_path
Date: Mon, 14 Sep 2020 15:17:03 -0400	[thread overview]
Message-ID: <20200914191707.380444-13-jlayton@kernel.org> (raw)
In-Reply-To: <20200914191707.380444-1-jlayton@kernel.org>

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.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
---
 fs/ceph/mds_client.c | 70 ++++++++++++++++++++++++++++++++++----------
 1 file changed, 54 insertions(+), 16 deletions(-)

diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index e3dc061252d4..7eb504170981 100644
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -2314,18 +2314,27 @@ static inline  u64 __get_oldest_tid(struct ceph_mds_client *mdsc)
 	return mdsc->oldest_tid;
 }
 
-/*
- * Build a dentry's path.  Allocate on heap; caller must kfree.  Based
- * on build_path_from_dentry in fs/cifs/dir.c.
+/**
+ * ceph_mdsc_build_path - build a path string to a given dentry
+ * @dentry: dentry to which path should be built
+ * @plen: returned length of string
+ * @pbase: returned base inode number
+ * @for_wire: is this path going to be sent to the MDS?
+ *
+ * Build a string that represents the path to the dentry. This is mostly called
+ * for two different purposes:
+ *
+ * 1) we need to build a path string to send to the MDS (for_wire == true)
+ * 2) we need a path string for local presentation (e.g. debugfs) (for_wire == false)
  *
- * If @stop_on_nosnap, generate path relative to the first non-snapped
- * inode.
+ * The path is built in reverse, starting with the dentry. Walk back up toward
+ * the root, building the path until the first non-snapped inode is reached (for_wire)
+ * or the root inode is reached (!for_wire).
  *
  * Encode hidden .snap dirs as a double /, i.e.
  *   foo/.snap/bar -> foo//bar
  */
-char *ceph_mdsc_build_path(struct dentry *dentry, int *plen, u64 *pbase,
-			   int stop_on_nosnap)
+char *ceph_mdsc_build_path(struct dentry *dentry, int *plen, u64 *pbase, int for_wire)
 {
 	struct dentry *cur;
 	struct inode *inode;
@@ -2347,30 +2356,59 @@ char *ceph_mdsc_build_path(struct dentry *dentry, int *plen, u64 *pbase,
 	seq = read_seqbegin(&rename_lock);
 	cur = dget(dentry);
 	for (;;) {
-		struct dentry *temp;
+		struct dentry *parent;
 
 		spin_lock(&cur->d_lock);
 		inode = d_inode(cur);
+		parent = cur->d_parent;
 		if (inode && ceph_snap(inode) == CEPH_SNAPDIR) {
 			dout("build_path path+%d: %p SNAPDIR\n",
 			     pos, cur);
-		} else if (stop_on_nosnap && inode && dentry != cur &&
-			   ceph_snap(inode) == CEPH_NOSNAP) {
+			dget(parent);
+			spin_unlock(&cur->d_lock);
+		} else if (for_wire && inode && dentry != cur && ceph_snap(inode) == CEPH_NOSNAP) {
 			spin_unlock(&cur->d_lock);
 			pos++; /* get rid of any prepended '/' */
 			break;
-		} else {
+		} else if (!for_wire || !IS_ENCRYPTED(d_inode(parent))) {
 			pos -= cur->d_name.len;
 			if (pos < 0) {
 				spin_unlock(&cur->d_lock);
 				break;
 			}
 			memcpy(path + pos, cur->d_name.name, cur->d_name.len);
+			dget(parent);
+			spin_unlock(&cur->d_lock);
+		} else {
+			int err;
+			struct fscrypt_name fname = { };
+			int len;
+			char buf[FSCRYPT_BASE64_CHARS(NAME_MAX)];
+
+			dget(parent);
+			spin_unlock(&cur->d_lock);
+
+			err = fscrypt_setup_filename(d_inode(parent), &cur->d_name, 1, &fname);
+			if (err) {
+				dput(parent);
+				dput(cur);
+				return ERR_PTR(err);
+			}
+
+			/* base64 encode the encrypted name */
+			len = fscrypt_base64_encode(fname.disk_name.name, fname.disk_name.len, buf);
+			pos -= len;
+			if (pos < 0) {
+				dput(parent);
+				fscrypt_free_filename(&fname);
+				break;
+			}
+			memcpy(path + pos, buf, len);
+			dout("non-ciphertext name = %.*s\n", len, buf);
+			fscrypt_free_filename(&fname);
 		}
-		temp = cur;
-		cur = dget(temp->d_parent);
-		spin_unlock(&temp->d_lock);
-		dput(temp);
+		dput(cur);
+		cur = parent;
 
 		/* Are we at the root? */
 		if (IS_ROOT(cur))
@@ -2415,7 +2453,7 @@ static int build_dentry_path(struct dentry *dentry, struct inode *dir,
 	rcu_read_lock();
 	if (!dir)
 		dir = d_inode_rcu(dentry->d_parent);
-	if (dir && parent_locked && ceph_snap(dir) == CEPH_NOSNAP) {
+	if (dir && parent_locked && ceph_snap(dir) == CEPH_NOSNAP && !IS_ENCRYPTED(dir)) {
 		*pino = ceph_ino(dir);
 		rcu_read_unlock();
 		*ppath = dentry->d_name.name;
-- 
2.26.2


  parent reply	other threads:[~2020-09-14 19:18 UTC|newest]

Thread overview: 48+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-14 19:16 [RFC PATCH v3 00/16] ceph+fscrypt: context, filename and symlink support Jeff Layton
2020-09-14 19:16 ` [RFC PATCH v3 01/16] vfs: export new_inode_pseudo Jeff Layton
2020-09-14 23:33   ` Eric Biggers
2020-09-23  3:41   ` Al Viro
2020-09-23 11:19     ` Jeff Layton
2020-09-14 19:16 ` [RFC PATCH v3 02/16] fscrypt: export fscrypt_base64_encode and fscrypt_base64_decode Jeff Layton
2020-09-14 23:44   ` Eric Biggers
2020-09-14 19:16 ` [RFC PATCH v3 03/16] fscrypt: export fscrypt_d_revalidate Jeff Layton
2020-09-15  0:04   ` Eric Biggers
2020-09-14 19:16 ` [RFC PATCH v3 04/16] fscrypt: add fscrypt_context_for_new_inode Jeff Layton
2020-09-15  0:15   ` Eric Biggers
2020-09-14 19:16 ` [RFC PATCH v3 05/16] fscrypt: make fscrypt_fname_disk_to_usr return whether result is nokey name Jeff Layton
2020-09-15  0:23   ` Eric Biggers
2020-09-14 19:16 ` [RFC PATCH v3 06/16] ceph: add fscrypt ioctls Jeff Layton
2020-09-15  0:45   ` Eric Biggers
2020-09-15 12:08     ` Jeff Layton
2020-09-14 19:16 ` [RFC PATCH v3 07/16] ceph: crypto context handling for ceph Jeff Layton
2020-09-15  1:00   ` Eric Biggers
2020-09-14 19:16 ` [RFC PATCH v3 08/16] ceph: implement -o test_dummy_encryption mount option Jeff Layton
2020-09-15  1:23   ` Eric Biggers
2020-09-16 12:49     ` Jeff Layton
2020-09-14 19:17 ` [RFC PATCH v3 09/16] ceph: preallocate inode for ops that may create one Jeff Layton
2020-09-15  1:30   ` Eric Biggers
2020-09-16 12:41     ` Jeff Layton
2020-09-14 19:17 ` [RFC PATCH v3 10/16] ceph: add routine to create context prior to RPC Jeff Layton
2020-09-15  1:37   ` Eric Biggers
2020-09-16 12:18     ` Jeff Layton
2020-09-14 19:17 ` [RFC PATCH v3 11/16] ceph: make ceph_msdc_build_path use ref-walk Jeff Layton
2020-09-14 19:17 ` Jeff Layton [this message]
2020-09-15  1:41   ` [RFC PATCH v3 12/16] ceph: add encrypted fname handling to ceph_mdsc_build_path Eric Biggers
2020-09-16 12:30     ` Jeff Layton
2020-09-16 17:36       ` Eric Biggers
2020-09-16 18:04         ` Jeff Layton
2020-09-16 18:42           ` Eric Biggers
2020-09-14 19:17 ` [RFC PATCH v3 13/16] ceph: make d_revalidate call fscrypt revalidator for encrypted dentries Jeff Layton
2020-09-14 19:17 ` [RFC PATCH v3 14/16] ceph: add support to readdir for encrypted filenames Jeff Layton
2020-09-15  1:57   ` Eric Biggers
2020-09-15 13:27     ` Jeff Layton
2020-09-15 20:40       ` Eric Biggers
2020-09-16 12:16         ` Jeff Layton
2020-09-14 19:17 ` [RFC PATCH v3 15/16] ceph: add fscrypt support to ceph_fill_trace Jeff Layton
2020-09-14 19:17 ` [RFC PATCH v3 16/16] ceph: create symlinks with encrypted and base64-encoded targets Jeff Layton
2020-09-15  2:07   ` Eric Biggers
2020-09-15 14:05     ` Jeff Layton
2020-09-15 20:49       ` Eric Biggers
2020-09-16 12:15         ` Jeff Layton
2020-09-15  2:13 ` [RFC PATCH v3 00/16] ceph+fscrypt: context, filename and symlink support Eric Biggers
2020-09-15 13:38   ` Jeff Layton

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