From patchwork Wed Jan 15 17:13:30 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: KP Singh X-Patchwork-Id: 1223736 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Original-To: incoming-bpf@patchwork.ozlabs.org Delivered-To: patchwork-incoming-bpf@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (no SPF record) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=bpf-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=pass (p=none dis=none) header.from=chromium.org Authentication-Results: ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=chromium.org header.i=@chromium.org header.a=rsa-sha256 header.s=google header.b=LBAXJRfH; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 47yYnr6FFjz9sRd for ; Thu, 16 Jan 2020 04:13:52 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729212AbgAORNa (ORCPT ); Wed, 15 Jan 2020 12:13:30 -0500 Received: from mail-wr1-f66.google.com ([209.85.221.66]:35327 "EHLO mail-wr1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729207AbgAORNa (ORCPT ); Wed, 15 Jan 2020 12:13:30 -0500 Received: by mail-wr1-f66.google.com with SMTP id g17so16517548wro.2 for ; Wed, 15 Jan 2020 09:13:29 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=BaXbvr8+/AA5pEwEC4kv+1bgxSxLzCBOcAqmhtuHoC8=; b=LBAXJRfH3GQwmfbGHhOP1Qs+7KpRm8fZjQ41I8LdOrmCDEDC2viG0gJQUFHB/CVPGk oj75ReZAzSfNOXgWbBKxLiPwi8i+/+EawU5XrPOsLq3jjkkBS1xYPzP1d0YrdhdZTiAm 6y9G1Av8SYD6NNmlGhd8DNjum6poEDVsfuZVo= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=BaXbvr8+/AA5pEwEC4kv+1bgxSxLzCBOcAqmhtuHoC8=; b=NM10AyDc1wk73R9CdHOaOtqSYZTTE38VF/KXVBF4ciq2ZChJMJPKVjRPt8RCTNCGv1 mzqay22VBYx24xJ5YXjckCTydYx+oKmNHGzhSTOm3V2ZFrseDw8s1cgnXr2r0DYVrIH/ +ryFBiRvT9ibM4CAG4fOVJlsitzkidBXDxDWWufRvU62orkslpLkF8KE/S+aVD4vujyP mZxUiRQEkhsEXioIt8uyShP0bXVV83vn6Yts/2y4dK0UwVDwc/5lprgxvKVqdk52KgtT q0aBigxT2y+yj09l5YAvTU1EnW8oUPQPBnJWFgyLDCps36+67HQQH/NoAMFxnRCdqWww zFTA== X-Gm-Message-State: APjAAAWuRtu1+cRu91Mrob+lo3eENfZQ9ghiUJuS7f9i/l+rJpZxwTaO Ke2UxaFsHFUAB4uMtTKR4k4khA== X-Google-Smtp-Source: APXvYqz+g9S4xsM16ZfhVtVBf5Pz0OA7zWuCU8BbSiBF/2A6sRIyLfsT4wowSgFNOpCHDbrvJcI30g== X-Received: by 2002:adf:df83:: with SMTP id z3mr33208227wrl.389.1579108408840; Wed, 15 Jan 2020 09:13:28 -0800 (PST) Received: from kpsingh-kernel.localdomain ([2620:0:105f:fd00:84f3:4331:4ae9:c5f1]) by smtp.gmail.com with ESMTPSA id d16sm26943227wrg.27.2020.01.15.09.13.27 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 15 Jan 2020 09:13:28 -0800 (PST) From: KP Singh To: linux-kernel@vger.kernel.org, bpf@vger.kernel.org, linux-security-module@vger.kernel.org Cc: Alexei Starovoitov , Daniel Borkmann , James Morris , Kees Cook , Thomas Garnier , Michael Halcrow , Paul Turner , Brendan Gregg , Jann Horn , Matthew Garrett , Christian Brauner , =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= , Florent Revest , Brendan Jackman , Martin KaFai Lau , Song Liu , Yonghong Song , "Serge E. Hallyn" , Mauro Carvalho Chehab , "David S. Miller" , Greg Kroah-Hartman , Nicolas Ferre , Stanislav Fomichev , Quentin Monnet , Andrey Ignatov , Joe Stringer Subject: [PATCH bpf-next v2 07/10] bpf: lsm: Make the allocated callback RO+X Date: Wed, 15 Jan 2020 18:13:30 +0100 Message-Id: <20200115171333.28811-8-kpsingh@chromium.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200115171333.28811-1-kpsingh@chromium.org> References: <20200115171333.28811-1-kpsingh@chromium.org> MIME-Version: 1.0 Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org From: KP Singh This patch is not needed after arch_bpf_prepare_trampoline moves to using text_poke. The two IPI TLB flushes can be further optimized if a new API to handle W^X in the kernel emerges as an outcome of: https://lore.kernel.org/bpf/20200103234725.22846-1-kpsingh@chromium.org/ Signed-off-by: KP Singh --- security/bpf/hooks.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/security/bpf/hooks.c b/security/bpf/hooks.c index 4e71da0e8e9e..30f68341f5ef 100644 --- a/security/bpf/hooks.c +++ b/security/bpf/hooks.c @@ -222,6 +222,15 @@ static struct bpf_lsm_hook *bpf_lsm_hook_alloc( goto error; } + /* First make the page read-only, and only then make it executable to + * prevent it from being W+X in between. + */ + set_memory_ro((unsigned long)image, 1); + /* More checks can be done here to ensure that nothing was changed + * between arch_prepare_bpf_trampoline and set_memory_ro. + */ + set_memory_x((unsigned long)image, 1); + hook = kzalloc(sizeof(struct bpf_lsm_hook), GFP_KERNEL); if (!hook) { ret = -ENOMEM;