tracefs: Update inode permissions on remount

When a remount happens, if a gid or uid is specified update the inodes to have the same gid and uid. This will allow the simplification of the permissions logic for the dynamically created files and directories. Link: https://lore.kernel.org/linux-trace-kernel/[email protected] Cc: [email protected] Cc: Masami Hiramatsu <[email protected]> Cc: Mark Rutland <[email protected]> Cc: Mathieu Desnoyers <[email protected]> Cc: Andrew Morton <[email protected]> Cc: Masahiro Yamada <[email protected]> Fixes: baa23a8 ("tracefs: Reset permissions on remount if permissions are options") Signed-off-by: Steven Rostedt (Google) <[email protected]>
noroot · May 23, 2024 · 27c0464 · 27c0464
1 parent 8898e7f
commit 27c0464
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Showing 2 changed files with 25 additions and 7 deletions.
diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
@@ -317,20 +317,29 @@ void eventfs_remount(struct tracefs_inode *ti, bool update_uid, bool update_gid)
 	if (!ei)
 		return;
 
-	if (update_uid)
+	if (update_uid) {
 		ei->attr.mode &= ~EVENTFS_SAVE_UID;
+		ei->attr.uid = ti->vfs_inode.i_uid;
+	}
+
 
-	if (update_gid)
+	if (update_gid) {
 		ei->attr.mode &= ~EVENTFS_SAVE_GID;
+		ei->attr.gid = ti->vfs_inode.i_gid;
+	}
 
 	if (!ei->entry_attrs)
 		return;
 
 	for (int i = 0; i < ei->nr_entries; i++) {
-		if (update_uid)
+		if (update_uid) {
 			ei->entry_attrs[i].mode &= ~EVENTFS_SAVE_UID;
-		if (update_gid)
+			ei->entry_attrs[i].uid = ti->vfs_inode.i_uid;
+		}
+		if (update_gid) {
 			ei->entry_attrs[i].mode &= ~EVENTFS_SAVE_GID;
+			ei->entry_attrs[i].gid = ti->vfs_inode.i_gid;
+		}
 	}
 }
 

diff --git a/fs/tracefs/inode.c b/fs/tracefs/inode.c
@@ -373,12 +373,21 @@ static int tracefs_apply_options(struct super_block *sb, bool remount)
 
 		rcu_read_lock();
 		list_for_each_entry_rcu(ti, &tracefs_inodes, list) {
-			if (update_uid)
+			if (update_uid) {
 				ti->flags &= ~TRACEFS_UID_PERM_SET;
+				ti->vfs_inode.i_uid = fsi->uid;
+			}
 
-			if (update_gid)
+			if (update_gid) {
 				ti->flags &= ~TRACEFS_GID_PERM_SET;
-
+				ti->vfs_inode.i_gid = fsi->gid;
+			}
+
+			/*
+			 * Note, the above ti->vfs_inode updates are
+			 * used in eventfs_remount() so they must come
+			 * before calling it.
+			 */
 			if (ti->flags & TRACEFS_EVENT_INODE)
 				eventfs_remount(ti, update_uid, update_gid);
 		}