Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Joonwon Kang <kjw1627@gmail.com>,
        Kees Cook <keescook@chromium.org>
Subject: [PATCH 4.19 156/211] randstruct: Check member structs in is_pure_ops_struct()
Date:   Thu,  3 Oct 2019 17:53:42 +0200
Message-Id: <20191003154523.683939067@linuxfoundation.org>
In-Reply-To: <20191003154447.010950442@linuxfoundation.org>
References: <20191003154447.010950442@linuxfoundation.org>
User-Agent: quilt/0.66
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

From: Joonwon Kang <kjw1627@gmail.com>

commit 60f2c82ed20bde57c362e66f796cf9e0e38a6dbb upstream.

While no uses in the kernel triggered this case, it was possible to have
a false negative where a struct contains other structs which contain only
function pointers because of unreachable code in is_pure_ops_struct().

Signed-off-by: Joonwon Kang <kjw1627@gmail.com>
Link: https://lore.kernel.org/r/20190727155841.GA13586@host
Fixes: 313dd1b62921 ("gcc-plugins: Add the randstruct plugin")
Cc: stable@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 scripts/gcc-plugins/randomize_layout_plugin.c |   10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

--- a/scripts/gcc-plugins/randomize_layout_plugin.c
+++ b/scripts/gcc-plugins/randomize_layout_plugin.c
@@ -443,13 +443,13 @@ static int is_pure_ops_struct(const_tree
 		if (node == fieldtype)
 			continue;
 
-		if (!is_fptr(fieldtype))
-			return 0;
-
-		if (code != RECORD_TYPE && code != UNION_TYPE)
+		if (code == RECORD_TYPE || code == UNION_TYPE) {
+			if (!is_pure_ops_struct(fieldtype))
+				return 0;
 			continue;
+		}
 
-		if (!is_pure_ops_struct(fieldtype))
+		if (!is_fptr(fieldtype))
 			return 0;
 	}