From: Xin Xiong <xiongx18@fudan.edu.cn>
Date: Thu, 28 Apr 2022 03:39:08 +0000 (+0800)
Subject: apparmor: fix reference count leak in aa_pivotroot()
X-Git-Tag: v5.15.73~980
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=64103ea357734b82384c925cba4758fdb909be0c;p=platform%2Fkernel%2Flinux-rpi.git

apparmor: fix reference count leak in aa_pivotroot()

commit 11c3627ec6b56c1525013f336f41b79a983b4d46 upstream.

The aa_pivotroot() function has a reference counting bug in a specific
path. When aa_replace_current_label() returns on success, the function
forgets to decrement the reference count of “target”, which is
increased earlier by build_pivotroot(), causing a reference leak.

Fix it by decreasing the refcount of “target” in that path.

Fixes: 2ea3ffb7782a ("apparmor: add mount mediation")
Co-developed-by: Xiyu Yang <xiyuyang19@fudan.edu.cn>
Signed-off-by: Xiyu Yang <xiyuyang19@fudan.edu.cn>
Co-developed-by: Xin Tan <tanxin.ctf@gmail.com>
Signed-off-by: Xin Tan <tanxin.ctf@gmail.com>
Signed-off-by: Xin Xiong <xiongx18@fudan.edu.cn>
Signed-off-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/security/apparmor/mount.c b/security/apparmor/mount.c
index 23aafe68..f7bb47d 100644
--- a/security/apparmor/mount.c
+++ b/security/apparmor/mount.c
@@ -719,6 +719,7 @@ int aa_pivotroot(struct aa_label *label, const struct path *old_path,
 			aa_put_label(target);
 			goto out;
 		}
+		aa_put_label(target);
 	} else
 		/* already audited error */
 		error = PTR_ERR(target);