From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kees Cook Subject: [PATCH] net: recvmsg: Unconditionally zero struct sockaddr_storage Date: Tue, 31 Oct 2017 09:14:45 -0700 Message-ID: <20171031161445.GA140874@beast> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Alexander Potapenko , Kostya Serebryany , Andrey Konovalov , Eric Dumazet , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, security@kernel.org To: "David S. Miller" Return-path: Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org Some protocols do not correctly wipe the contents of the on-stack struct sockaddr_storage sent down into recvmsg() (e.g. SCTP), and leak kernel stack contents to userspace. This wipes it unconditionally before per-protocol handlers run. Note that leaks like this are mitigated by building with CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL=y Reported-by: Alexander Potapenko Cc: "David S. Miller" Cc: netdev@vger.kernel.org Signed-off-by: Kees Cook --- net/socket.c | 1 + 1 file changed, 1 insertion(+) diff --git a/net/socket.c b/net/socket.c index c729625eb5d3..34183f4fbdf8 100644 --- a/net/socket.c +++ b/net/socket.c @@ -2188,6 +2188,7 @@ static int ___sys_recvmsg(struct socket *sock, struct user_msghdr __user *msg, struct sockaddr __user *uaddr; int __user *uaddr_len = COMPAT_NAMELEN(msg); + memset(&addr, 0, sizeof(addr)); msg_sys->msg_name = &addr; if (MSG_CMSG_COMPAT & flags) -- 2.7.4 -- Kees Cook Pixel Security