From patchwork Fri Dec 6 22:13:47 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sami Tolvanen X-Patchwork-Id: 11277103 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 8549214BD for ; Fri, 6 Dec 2019 22:16:53 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 6294421835 for ; Fri, 6 Dec 2019 22:16:53 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="k4kym2/c"; dkim=fail reason="signature verification failed" (2048-bit key) header.d=google.com header.i=@google.com header.b="c1Wx0pmg" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6294421835 Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:To:From:Subject:References:Mime-Version :Message-Id:In-Reply-To:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=zo1UZkjVlNrrElhcRf/mUeyojspUB6NRjHXZPAwGEF8=; b=k4kym2/cOsx7nO /Z1ajQ2brw89bB16u5JRI1eBXOyyFzz8knnvgzGloVuR4JQ+Nk7lLwdbtB+EvF5zQqwkeaMSyEUwd 269lYzcqQlFKTHk8GMd4UJg5juDgvizryX8P0zgK6Q1UxoQQFZZ+GvH7l7nDmRvWxuPXtzLw47mnu sw3Bz7tVavIVUJasiXJVFmj7UT/BJWKby44Pu+ypK161F8NufWd5k18cNDn1V4AMm7l60UrkdwCeJ e/NnGCeaLwaqe1UL6Lq/g03ptSjxN5MV4JftAny7ILzwJePedVg790+GIvKHnEl+8aswMaeR3Q4WH SzUJoSLPekgQ3zRlKzyQ==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1idLu6-0001mi-HG; Fri, 06 Dec 2019 22:16:50 +0000 Received: from mail-qv1-xf4a.google.com ([2607:f8b0:4864:20::f4a]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1idLrm-0006nK-JM for linux-arm-kernel@lists.infradead.org; Fri, 06 Dec 2019 22:14:31 +0000 Received: by mail-qv1-xf4a.google.com with SMTP id q17so724891qvo.23 for ; Fri, 06 Dec 2019 14:14:25 -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=FhYYEjTDkPuKHbZnKePlOaf9pf8CUWO3nD3sOS+po+M=; b=c1Wx0pmgZzJDLcr5nKIxS6pdb72MNBZXygUHxUgHfIREUjivSfJmFNkd4nH821+c7c XdMpdHUqSUmAmYnv/wYcSmRCYqJtUh+jdTQ3/0TYFxbvGCg3KubysunPGfqG0BjN6R5p FZYsTRty1KKiwCF3GFPmHDSfqSVDKBB9Dl9Svv8Esh85iZQ6Gp8IldBOuKDVG0NAYrct KCNN1c4Jt5Qnd9QE5BIqwUiELeUVYdQWv32ArtiqQbBLSzZpaS8483/PTd49tfr3IpbZ ZlBwyqxJM8pdiJ2dTz9waDv/2F+kWZdAUGGPKaihus1bQ20pRuQajRsHhJifC3dGS/Vz k2Wg== 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=FhYYEjTDkPuKHbZnKePlOaf9pf8CUWO3nD3sOS+po+M=; b=Jkzi8arFKRlTYyUyv1P3mCTnXzsZNWTFaNjMBnaWyZNTA87BLM6rbVae2B0T6eb5Ri h70+yUNBfcTHvwP+bnL3AM3mIeFcowgk56a/320eAlWxtdz2DspLcgdMt98FBCOgPouF OlpsFZO0QqmZofwS0t9A5+T677i0aL3jFKGO5o5huqCwnW/NryC7uwOL2npBu3hIChEX RoHWBwBx5zV5PJmYPyaqQJBruTI+vkZWPlE3EQCb38B45VMJ0pYvGljB4n3OFNN0dK87 w/+8YSP74feSSw1JH/4VpAnR40nJqUSVddlhibx2V06X3/URH3xnmdMZ1RRp40eHJgXc jbww== X-Gm-Message-State: APjAAAXKnHmsRwrzDpXZ4YocYpuT7uQZgCz0YXjnD+O3FNRqmAt3Pifv GeM90RBRP5YkufE86GOMDcnMFHKJMck5nEup9AY= X-Google-Smtp-Source: APXvYqwZLBeooXOHcOO29WvEdpgbxookvNvj944sJ15kbZCCqA2Ea8mnulB5DEVBZW8wLWpSg85W/yQRRXH7nkmyS6o= X-Received: by 2002:ac8:2201:: with SMTP id o1mr15071384qto.247.1575670464028; Fri, 06 Dec 2019 14:14:24 -0800 (PST) Date: Fri, 6 Dec 2019 14:13:47 -0800 In-Reply-To: <20191206221351.38241-1-samitolvanen@google.com> Message-Id: <20191206221351.38241-12-samitolvanen@google.com> Mime-Version: 1.0 References: <20191018161033.261971-1-samitolvanen@google.com> <20191206221351.38241-1-samitolvanen@google.com> X-Mailer: git-send-email 2.24.0.393.g34dc348eaf-goog Subject: [PATCH v6 11/15] arm64: efi: restore x18 if it was corrupted From: Sami Tolvanen To: Will Deacon , Catalin Marinas , Steven Rostedt , Masami Hiramatsu , Ard Biesheuvel , Mark Rutland X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20191206_141426_673779_AEDC41F2 X-CRM114-Status: UNSURE ( 9.76 ) X-CRM114-Notice: Please train this message. X-Spam-Score: -7.7 (-------) X-Spam-Report: SpamAssassin version 3.4.2 on bombadil.infradead.org summary: Content analysis details: (-7.7 points) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 SPF_PASS SPF: sender matches SPF record 0.0 SPF_HELO_NONE SPF: HELO does not publish an SPF Record -7.5 USER_IN_DEF_DKIM_WL From: address is in the default DKIM white-list -0.1 DKIM_VALID Message has at least one valid DKIM or DK signature 0.1 DKIM_SIGNED Message has a DKIM or DK signature, not necessarily valid -0.1 DKIM_VALID_AU Message has a valid DKIM or DK signature from author's domain -0.1 DKIM_VALID_EF Message has a valid DKIM or DK signature from envelope-from domain -0.0 DKIMWL_WL_MED DKIMwl.org - Medium sender X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kees Cook , Jann Horn , Masahiro Yamada , Marc Zyngier , kernel-hardening@lists.openwall.com, Nick Desaulniers , linux-kernel@vger.kernel.org, Miguel Ojeda , clang-built-linux@googlegroups.com, Sami Tolvanen , Laura Abbott , Dave Martin , linux-arm-kernel@lists.infradead.org Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.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 | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/arch/arm64/kernel/efi-rt-wrapper.S b/arch/arm64/kernel/efi-rt-wrapper.S index 3fc71106cb2b..62f0260f5c17 100644 --- a/arch/arm64/kernel/efi-rt-wrapper.S +++ b/arch/arm64/kernel/efi-rt-wrapper.S @@ -34,5 +34,14 @@ 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. This is + * safe because the wrapper is called with preemption disabled and + * a separate shadow stack is used for interrupts. + */ + mov x18, x2 +#endif + b efi_handle_corrupted_x18 // tail call ENDPROC(__efi_rt_asm_wrapper)