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 79D72CA9ECF for ; Fri, 1 Nov 2019 22:12:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4BAFA21897 for ; Fri, 1 Nov 2019 22:12:38 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="odv3zPa4" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728052AbfKAWMg (ORCPT ); Fri, 1 Nov 2019 18:12:36 -0400 Received: from mail-pg1-f201.google.com ([209.85.215.201]:34362 "EHLO mail-pg1-f201.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727984AbfKAWMd (ORCPT ); Fri, 1 Nov 2019 18:12:33 -0400 Received: by mail-pg1-f201.google.com with SMTP id w9so8024093pgl.1 for ; Fri, 01 Nov 2019 15:12:32 -0700 (PDT) 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=odv3zPa4RgQ8s6dsoDxvbsmHF3EENGYKEFkki0g9WgsTtiUy1PWOo4QagxAFwNjlM5 UaXo+6ESXS0tfN9t/uaTyImKPgoUdkbU5/6mXIU+WDuhuaMZVZlToQjZBZjUeJ+XCKaN AZaYtQv4cn3jcrlvgSVPiMAL2aX2o/kWtvg0ZhsbFx5XNHfG27Zn+lw1m2rgEzTuN0Qx AhXuI7DUwTtXfZmNooQs1nB+s/Ns/DX1LvGMoiAbd56F3AJ+mJtqGL8w4imrJ9czieHh o3BNgiNlRATQnbvYsOjBOz35StnAU9Usdu1hP8mnieHo1tIou+WOWs5WVmR96RMvFpMw BkXA== 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=JRsd1OoxwUo2NzT14V0OYPf6AAV4+UFk1SwrcaLYnLwKMw2LN/hXm6etAP0F+0zisR /gdZPPeNHrhaDqgL6QiteQRigpYKO7LNKJ9vvu6sQgZoVtD4uspI5RxjxjNKrd4CfMNx ZkH9qkD1dV1KAFosF9Yzh2MIvvc9CQPdNUid4o0agEfJvtvJQjyXMDfQVjxI5NIRKLym qth/dTi4MUv/85gPo5ABjIZVrB+EjKyBI0aS7xidPpmGUaFqNSP9RX2c0JLGcPz/JWph cEUGaBoPUM2BNJhr6Ofpf5WvacBK8/o/m7EN6iNm0Y11pZONGBajWv1xkuZT0cZ7song 3YTQ== X-Gm-Message-State: APjAAAXZP1VxjRLknhlWQ+bJcPdY0fLYaz1f7yEPFwr0bxx1/+oozgTo yc6yxwbBVX5Px9d2x62+Cu8n0/BZmhu6qEnaq+w= X-Google-Smtp-Source: APXvYqxnvjccMKGZa+EMFNvyVvl4JQq0YHBc8XNC8xBIuIHK+TPnyLwR96cD6M+G58PTtTiYueuKAoyE/cNOXhTJ/L8= X-Received: by 2002:a63:3203:: with SMTP id y3mr15810585pgy.437.1572646351983; Fri, 01 Nov 2019 15:12:31 -0700 (PDT) Date: Fri, 1 Nov 2019 15:11:47 -0700 In-Reply-To: <20191101221150.116536-1-samitolvanen@google.com> Message-Id: <20191101221150.116536-15-samitolvanen@google.com> Mime-Version: 1.0 References: <20191018161033.261971-1-samitolvanen@google.com> <20191101221150.116536-1-samitolvanen@google.com> X-Mailer: git-send-email 2.24.0.rc1.363.gb1bccd3e3d-goog Subject: [PATCH v4 14/17] 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