From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f199.google.com (mail-pf0-f199.google.com [209.85.192.199]) by kanga.kvack.org (Postfix) with ESMTP id 833956B02B7 for ; Wed, 20 Sep 2017 16:53:00 -0400 (EDT) Received: by mail-pf0-f199.google.com with SMTP id a7so6509328pfj.3 for ; Wed, 20 Sep 2017 13:53:00 -0700 (PDT) Received: from mail-sor-f41.google.com (mail-sor-f41.google.com. [209.85.220.41]) by mx.google.com with SMTPS id 142sor2108180pgg.288.2017.09.20.13.52.59 for (Google Transport Security); Wed, 20 Sep 2017 13:52:59 -0700 (PDT) From: Kees Cook Subject: [PATCH v3 18/31] net: Define usercopy region in struct proto slab cache Date: Wed, 20 Sep 2017 13:45:24 -0700 Message-Id: <1505940337-79069-19-git-send-email-keescook@chromium.org> In-Reply-To: <1505940337-79069-1-git-send-email-keescook@chromium.org> References: <1505940337-79069-1-git-send-email-keescook@chromium.org> Sender: owner-linux-mm@kvack.org List-ID: To: linux-kernel@vger.kernel.org Cc: Kees Cook , David Windsor , "David S. Miller" , Eric Dumazet , Paolo Abeni , David Howells , netdev@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, kernel-hardening@lists.openwall.com From: David Windsor In support of usercopy hardening, this patch defines a region in the struct proto slab cache in which userspace copy operations are allowed. Some protocols need to copy objects to/from userspace, and they can declare the region via their proto structure with the new usersize and useroffset fields. Initially, if no region is specified (usersize == 0), the entire field is marked as whitelisted. This allows protocols to be whitelisted in subsequent patches. Once all protocols have been annotated, the full-whitelist default can be removed. 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: adjust commit log, split off per-proto patches] [kees: add logic for by-default full-whitelist] Cc: "David S. Miller" Cc: Eric Dumazet Cc: Paolo Abeni Cc: David Howells Cc: netdev@vger.kernel.org Signed-off-by: Kees Cook --- include/net/sock.h | 2 ++ net/core/sock.c | 6 +++++- 2 files changed, 7 insertions(+), 1 deletion(-) diff --git a/include/net/sock.h b/include/net/sock.h index 03a362568357..13c2d1b48c86 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -1106,6 +1106,8 @@ struct proto { struct kmem_cache *slab; unsigned int obj_size; int slab_flags; + size_t useroffset; /* Usercopy region offset */ + size_t usersize; /* Usercopy region size */ struct percpu_counter *orphan_count; diff --git a/net/core/sock.c b/net/core/sock.c index 9b7b6bbb2a23..832dfb03102e 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -3165,8 +3165,12 @@ static int req_prot_init(const struct proto *prot) int proto_register(struct proto *prot, int alloc_slab) { if (alloc_slab) { - prot->slab = kmem_cache_create(prot->name, prot->obj_size, 0, + prot->slab = kmem_cache_create_usercopy(prot->name, + prot->obj_size, 0, SLAB_HWCACHE_ALIGN | prot->slab_flags, + prot->usersize ? prot->useroffset : 0, + prot->usersize ? prot->usersize + : prot->obj_size, NULL); if (prot->slab == NULL) { -- 2.7.4 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org