Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751811AbdH1Vox (ORCPT ); Mon, 28 Aug 2017 17:44:53 -0400 Received: from mail-pg0-f54.google.com ([74.125.83.54]:37652 "EHLO mail-pg0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751396AbdH1Vn4 (ORCPT ); Mon, 28 Aug 2017 17:43:56 -0400 From: Kees Cook To: linux-kernel@vger.kernel.org Cc: Kees Cook , David Windsor , "David S. Miller" , Alexey Kuznetsov , Hideaki YOSHIFUJI , netdev@vger.kernel.org, linux-mm@kvack.org, kernel-hardening@lists.openwall.com Subject: [PATCH v2 19/30] ip: Define usercopy region in IP proto slab cache Date: Mon, 28 Aug 2017 14:35:00 -0700 Message-Id: <1503956111-36652-20-git-send-email-keescook@chromium.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1503956111-36652-1-git-send-email-keescook@chromium.org> References: <1503956111-36652-1-git-send-email-keescook@chromium.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2623 Lines: 76 From: David Windsor The ICMP filters for IPv4 and IPv6 raw sockets need to be copied to/from userspace. In support of usercopy hardening, this patch defines a region in the struct proto slab cache in which userspace copy operations are allowed. example usage trace: net/ipv4/raw.c: raw_seticmpfilter(...): ... copy_from_user(&raw_sk(sk)->filter, ..., optlen) raw_geticmpfilter(...): ... copy_to_user(..., &raw_sk(sk)->filter, len) net/ipv6/raw.c: rawv6_seticmpfilter(...): ... copy_from_user(&raw6_sk(sk)->filter, ..., optlen) rawv6_geticmpfilter(...): ... copy_to_user(..., &raw6_sk(sk)->filter, len) This region is known as the slab cache's usercopy region. Slab caches can now check that each copy operation involving cache-managed memory falls entirely within the slab's usercopy region. This patch is modified 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 [kees: split from network patch, provide usage trace] Cc: "David S. Miller" Cc: Alexey Kuznetsov Cc: Hideaki YOSHIFUJI Cc: netdev@vger.kernel.org Signed-off-by: Kees Cook --- net/ipv4/raw.c | 2 ++ net/ipv6/raw.c | 2 ++ 2 files changed, 4 insertions(+) diff --git a/net/ipv4/raw.c b/net/ipv4/raw.c index b0bb5d0a30bd..6c7f8d2eb3af 100644 --- a/net/ipv4/raw.c +++ b/net/ipv4/raw.c @@ -964,6 +964,8 @@ struct proto raw_prot = { .hash = raw_hash_sk, .unhash = raw_unhash_sk, .obj_size = sizeof(struct raw_sock), + .useroffset = offsetof(struct raw_sock, filter), + .usersize = sizeof_field(struct raw_sock, filter), .h.raw_hash = &raw_v4_hashinfo, #ifdef CONFIG_COMPAT .compat_setsockopt = compat_raw_setsockopt, diff --git a/net/ipv6/raw.c b/net/ipv6/raw.c index 60be012fe708..27dd9a5f71c6 100644 --- a/net/ipv6/raw.c +++ b/net/ipv6/raw.c @@ -1265,6 +1265,8 @@ struct proto rawv6_prot = { .hash = raw_hash_sk, .unhash = raw_unhash_sk, .obj_size = sizeof(struct raw6_sock), + .useroffset = offsetof(struct raw6_sock, filter), + .usersize = sizeof_field(struct raw6_sock, filter), .h.raw_hash = &raw_v6_hashinfo, #ifdef CONFIG_COMPAT .compat_setsockopt = compat_rawv6_setsockopt, -- 2.7.4