proc: don't allow async path resolution of /proc/self components

[ Upstream commit 8d4c3e76e3be11a64df95ddee52e99092d42fc19 ] If this is attempted by a kthread, then return -EOPNOTSUPP as we don't currently support that. Once we can get task_pid_ptr() doing the right thing, then this can go away again. Signed-off-by: Jens Axboe <[email protected]> Signed-off-by: Sasha Levin <[email protected]>
radcolor · Dec 2, 2020 · ebb83fd · ebb83fd
1 parent 22aaeae
commit ebb83fd
Showing 1 changed file with 7 additions and 0 deletions.
diff --git a/fs/proc/self.c b/fs/proc/self.c
@@ -24,6 +24,13 @@ static const char *proc_self_follow_link(struct dentry *dentry, void **cookie)
 	pid_t tgid = task_tgid_nr_ns(current, ns);
 	char *name;
 
+	/*
+	 * Not currently supported. Once we can inherit all of struct pid,
+	 * we can allow this.
+	 */
+	if (current->flags & PF_KTHREAD)
+		return ERR_PTR(-EOPNOTSUPP);
+
 	if (!tgid)
 		return ERR_PTR(-ENOENT);
 	/* 11 for max length of signed int in decimal + NULL term */