From ce285c267a003acbf607f3540ff71287f82e5282 Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Tue, 2 Apr 2019 15:17:34 -0400
Subject: [PATCH] autofs: fix use-after-free in lockless ->d_manage()
autofs_d_release() can overlap with lockless ->d_manage(),
ending up with autofs_dentry_ino() freed under the latter.
Make freeing autofs_info instances RCU-delayed...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
fs/autofs/autofs_i.h | 1 +
fs/autofs/inode.c | 2 +-
2 files changed, 2 insertions(+), 1 deletion(-)
diff --git a/fs/autofs/autofs_i.h b/fs/autofs/autofs_i.h
index 70c132acdab1..e1091312abe1 100644
--- a/fs/autofs/autofs_i.h
+++ b/fs/autofs/autofs_i.h
@@ -71,6 +71,7 @@ struct autofs_info {
kuid_t uid;
kgid_t gid;
+ struct rcu_head rcu;
};
#define AUTOFS_INF_EXPIRING (1<<0) /* dentry in the process of expiring */
diff --git a/fs/autofs/inode.c b/fs/autofs/inode.c
index 80597b88718b..fb0225f21c12 100644
--- a/fs/autofs/inode.c
+++ b/fs/autofs/inode.c
@@ -36,7 +36,7 @@ void autofs_clean_ino(struct autofs_info *ino)
void autofs_free_ino(struct autofs_info *ino)
{
- kfree(ino);
+ kfree_rcu(ino, rcu);
}
void autofs_kill_sb(struct super_block *sb)