Commit b2ce04c2 authored Jun 10, 2017 by David Windsor Committed by Kees Cook Jan 15, 2018

sctp: Copy struct sctp_sock.autoclose to userspace using put_user()



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@nullcore.net>
[kees: adjust commit log]
Cc: Vlad Yasevich <vyasevich@gmail.com>
Cc: Neil Horman <nhorman@tuxdriver.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: linux-sctp@vger.kernel.org
Cc: netdev@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>

parent ab9ee8e3

net/sctp/socket.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -5011,7 +5011,7 @@ 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;
		}