From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-17.4 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT,USER_IN_DEF_DKIM_WL autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B424DC5DF60 for ; Tue, 5 Nov 2019 23:56:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5CBFF21A49 for ; Tue, 5 Nov 2019 23:56:51 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="JN9cRXW3" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387620AbfKEX4u (ORCPT ); Tue, 5 Nov 2019 18:56:50 -0500 Received: from mail-pg1-f202.google.com ([209.85.215.202]:42335 "EHLO mail-pg1-f202.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387588AbfKEX4q (ORCPT ); Tue, 5 Nov 2019 18:56:46 -0500 Received: by mail-pg1-f202.google.com with SMTP id k12so16231926pgj.9 for ; Tue, 05 Nov 2019 15:56:46 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=uZ/kQt4EYM2LvpfCusnWoxftHyD2DxgcHTICv7X7dqw=; b=JN9cRXW3eTB7Z2OFW88PXu3tlOY8dStgQEbY8qRUEgweBu4PUIX8TxJ8b95mM5amMG dY/gdqPeBwxcAj5lhK+CRHRd9Y9Vpp0cdvG07lguYzEIxlPQjlLTWMX36AhhMbrOp+bu Cl6hQENGtphPESeiB1wGFAywqSFr434R5npfiMW2A0Y8vIjGPZh4zUIbEexaOWFxdCOT CLAJQw1H0pC3jFL2n55/3yC6h22GnBsHily047age54Pgx3FfV4IqFsu4AOA5+wZCKOA Vh966NbyvN58mnGWJfBhXw2nRYEngLWud/TUyZ3xl1yXKU0boesH5G03NhQo6gYktAXR HQGw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=uZ/kQt4EYM2LvpfCusnWoxftHyD2DxgcHTICv7X7dqw=; b=skWRlTsTzM5clpePKdWzNnIM35IH7ZS9cit8WPqQj9hHBclc2wUsgaSDBEkYWwpeIA 58A3WpU18sV1P1fTIfYaw6ZQN0/epvSaKakDPOtS6uWTIheNjaMSzgGZEc4bRPguJ3E/ jul8XQ+0qio7wXO2kVlOPPOe03GlZQtVlcSw+e1dyyf6HT8GfG2a2xtszR8U/yL4nXOx ZRA8jNwkr4S+O+oRXFOYNK2xTcBrlXp1dwpx3XflK7npK2xLfeCERGYX/ePnql2vFdfK kbzy9JF7Ck2/yQzOS1EnLusHH9M2BHIcU0hqhFzoltaZL84Wcs3P7LTu+AX0yOhEWkFJ 9M2Q== X-Gm-Message-State: APjAAAVaqjAt9kQ96YcszXPWqWHTdn5OnRzfK5yYcjdW9ABHmD5Cyjbh /sdj/xVh5WnDRdQQjMJhIHBnwaPedA7DjGyHvns= X-Google-Smtp-Source: APXvYqxTWXWUBEJ0UiXFjDLjnNptoAXq2B85FgeAZV4DWhGGMZ0/dSlB0BXzaBE92E4TUaHE+e4XmBjxNCDfcOvMvRU= X-Received: by 2002:a65:5a8c:: with SMTP id c12mr39559106pgt.140.1572998205590; Tue, 05 Nov 2019 15:56:45 -0800 (PST) Date: Tue, 5 Nov 2019 15:56:05 -0800 In-Reply-To: <20191105235608.107702-1-samitolvanen@google.com> Message-Id: <20191105235608.107702-12-samitolvanen@google.com> Mime-Version: 1.0 References: <20191018161033.261971-1-samitolvanen@google.com> <20191105235608.107702-1-samitolvanen@google.com> X-Mailer: git-send-email 2.24.0.rc1.363.gb1bccd3e3d-goog Subject: [PATCH v5 11/14] arm64: efi: restore x18 if it was corrupted From: Sami Tolvanen To: Will Deacon , Catalin Marinas , Steven Rostedt , Masami Hiramatsu , Ard Biesheuvel Cc: Dave Martin , Kees Cook , Laura Abbott , Mark Rutland , Marc Zyngier , Nick Desaulniers , Jann Horn , Miguel Ojeda , Masahiro Yamada , clang-built-linux@googlegroups.com, kernel-hardening@lists.openwall.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Sami Tolvanen Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org If we detect a corrupted x18 and SCS is enabled, restore the register before jumping back to instrumented code. This is safe, because the wrapper is called with preemption disabled and a separate shadow stack is used for interrupt handling. Signed-off-by: Sami Tolvanen Reviewed-by: Kees Cook --- arch/arm64/kernel/efi-rt-wrapper.S | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/arch/arm64/kernel/efi-rt-wrapper.S b/arch/arm64/kernel/efi-rt-wrapper.S index 3fc71106cb2b..945744f16086 100644 --- a/arch/arm64/kernel/efi-rt-wrapper.S +++ b/arch/arm64/kernel/efi-rt-wrapper.S @@ -34,5 +34,10 @@ ENTRY(__efi_rt_asm_wrapper) ldp x29, x30, [sp], #32 b.ne 0f ret -0: b efi_handle_corrupted_x18 // tail call +0: +#ifdef CONFIG_SHADOW_CALL_STACK + /* Restore x18 before returning to instrumented code. */ + mov x18, x2 +#endif + b efi_handle_corrupted_x18 // tail call ENDPROC(__efi_rt_asm_wrapper) -- 2.24.0.rc1.363.gb1bccd3e3d-goog