linux-kernel - [PATCH 16/23] net: copy struct sctp_sock.autoclose to userspace using put

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <1497915397-93805-17-git-send-email-keescook@chromium.org>
Date:   Mon, 19 Jun 2017 16:36:30 -0700
From:   Kees Cook <keescook@...omium.org>
To:     kernel-hardening@...ts.openwall.com
Cc:     Kees Cook <keescook@...omium.org>,
        David Windsor <dave@...lcore.net>, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH 16/23] net: copy struct sctp_sock.autoclose to userspace using put_user()

From: David Windsor <dave@...lcore.net>

The autoclose field can be copied with put_user(), so there is no need to
use copy_to_user(). In both cases, hardened usercopy is being bypassed
since the size is constant, and not open to runtime manipulation.

This patch is verbatim from Brad Spengler/PaX Team's PAX_USERCOPY
whitelisting code in the last public patch of grsecurity/PaX based on my
understanding of the code. Changes or omissions from the original code are
mine and don't reflect the original grsecurity/PaX code.

Signed-off-by: David Windsor <dave@...lcore.net>
[kees: adjust commit log]
Signed-off-by: Kees Cook <keescook@...omium.org>
---
 net/sctp/socket.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index 0defc0c76552..e94c141bcf82 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -4883,7 +4883,7 @@ static int sctp_getsockopt_autoclose(struct sock *sk, int len, char __user *optv
 	len = sizeof(int);
 	if (put_user(len, optlen))
 		return -EFAULT;
-	if (copy_to_user(optval, &sctp_sk(sk)->autoclose, sizeof(int)))
+	if (put_user(sctp_sk(sk)->autoclose, (int __user *)optval))
 		return -EFAULT;
 	return 0;
 }
-- 
2.7.4