From patchwork Thu Apr 16 16:12:40 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sami Tolvanen X-Patchwork-Id: 11493451 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 A765C1392 for ; Thu, 16 Apr 2020 16:16:03 +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 68C9122244 for ; Thu, 16 Apr 2020 16:16:03 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="V3KtH7yt"; dkim=fail reason="signature verification failed" (2048-bit key) header.d=google.com header.i=@google.com header.b="PfLQtJvA" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 68C9122244 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=m6TCsK+1j1uXcB39Ra/ToHMdhQBgLoOyyF61hntHH+w=; b=V3KtH7ytF/3brd GSLYNrV4EtGafk12d983ezeAkcLl0ZnmweAzlRoNRpnk9BLPFhPiHHDU9wK4aDh0Pona9iT49EHbE lVSGJGc5ug3yioLR3JnfYXxj7LUsT4hFQoBCrQ3nS8BjWwkLr4/hMI9ne5K+ny0a6fVBZrofY16qu X6XZ+7Rul8zxh87g+QAYpr0a1LGYaqzBVpvMH4k3JDdaZB7D4DfwV3ivT0vRTe4DyzPAWj9497z42 ILakWtITJqVZl+OJmhtKE5iPtoZVIdr+feFjDD7sMSUG63tcRw0InXuLraSvXgP8JPCSz3GydWPuO hsOPYADV1fvaBhChmdtw==; 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 1jP7BD-0000P5-Th; Thu, 16 Apr 2020 16:15:55 +0000 Received: from mail-pf1-x44a.google.com ([2607:f8b0:4864:20::44a]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1jP78X-0003l0-Iw for linux-arm-kernel@lists.infradead.org; Thu, 16 Apr 2020 16:13:18 +0000 Received: by mail-pf1-x44a.google.com with SMTP id y84so3445632pfb.7 for ; Thu, 16 Apr 2020 09:13:07 -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=ir6AMcU/LNJfVmH7TAbfuSTmLjnaQbzCZFrLbu9sicg=; b=PfLQtJvAzz5yI91olwSgmzdmwgdtJxdSpUwDBUqAfM/Qj4X8PTnr8pe6M1E9q+SxMQ 9DuGyRyHutXrki59bdmwIERRsNZo12qtXtT7YTGaQUvErlBRD5mI0A9o3BWgwYogesFw pJQazMuF7VSg8nXXNbbuwnalk1A8GI2siOE+gzAVLDi5SEfj4qBjBhPGSFAFigx0XT27 2J6qu4mUgNZPuqq+yi7V5b3R7FRrHRFEL+uzZRZfJJCkuZ3Y9YcoQ6IkCgna/0CQ22Jg qGjnRtJiwEZAIC0v5v+CcPVf8e5pwqpO5XgzgToKbUlUPQ54YIcNjAxSzrtDUK8hBIAD 0GIQ== 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=ir6AMcU/LNJfVmH7TAbfuSTmLjnaQbzCZFrLbu9sicg=; b=sd1F8ztoKhk3AuSKBpZImdAmF3X8gzU9SCrFMbG8rXLE1mbMMb2GX01kQW4yr2xMsV tEYRxQZtFgUBVxCm6IU+Gz48Y5qozCZPIj7hrBJ5o/XldbEhDJlPXUqDlUgbh2ftL0qt L5hNBzk83UcyZcb7ofcJQI/SO8LdFZbpzp2u8tP6PxPav9dWYGZJw438ocXIMHAzJ6RR CRO7nyM0taVFKRMf+/7HUcajrcIAFCoxKN3KZZxTT+9zhS45PnYDdk63227s4PhhkA92 /hAVLS/ys3j5pn7onu8hhk7q+mZz7SxTpjtd9YxgjffTReQAjWB03KaQ5oI8X1e8m9tv 94wA== X-Gm-Message-State: AGi0PuYsx3q6o8IXwnCQMZkp5F1RnlKFGg4p3MIglb9bJVoLAfka6GTQ 6ZZyWI3J+Hhg5C7mb3kN3v58U9VFR9k/w/TVS1k= X-Google-Smtp-Source: APiQypLtd8ftrhqgq/6RnJ5qnFSnfzNaIUqdmQcwCsxZfxvN3FzC3GYwf1kFiAS1IaIXQEFXlhjHe+bl82oElgHqTYg= X-Received: by 2002:a17:90a:cc10:: with SMTP id b16mr5944791pju.29.1587053586616; Thu, 16 Apr 2020 09:13:06 -0700 (PDT) Date: Thu, 16 Apr 2020 09:12:40 -0700 In-Reply-To: <20200416161245.148813-1-samitolvanen@google.com> Message-Id: <20200416161245.148813-8-samitolvanen@google.com> Mime-Version: 1.0 References: <20191018161033.261971-1-samitolvanen@google.com> <20200416161245.148813-1-samitolvanen@google.com> X-Mailer: git-send-email 2.26.1.301.g55bc3eb7cb9-goog Subject: [PATCH v11 07/12] arm64: efi: restore x18 if it was corrupted From: Sami Tolvanen To: Will Deacon , Catalin Marinas , James Morse , Steven Rostedt , Ard Biesheuvel , Mark Rutland , Masahiro Yamada , Michal Marek , Ingo Molnar , Peter Zijlstra , Juri Lelli , Vincent Guittot X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200416_091309_651951_C9BB9FFB X-CRM114-Status: GOOD ( 11.01 ) X-Spam-Score: -7.7 (-------) X-Spam-Report: SpamAssassin version 3.4.4 on bombadil.infradead.org summary: Content analysis details: (-7.7 points) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 RCVD_IN_DNSWL_NONE RBL: Sender listed at https://www.dnswl.org/, no trust [2607:f8b0:4864:20:0:0:0:44a listed in] [list.dnswl.org] 0.0 SPF_HELO_NONE SPF: HELO does not publish an SPF Record -0.0 SPF_PASS SPF: sender matches SPF record -7.5 USER_IN_DEF_DKIM_WL From: address is in the default DKIM white-list 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 -0.1 DKIM_VALID Message has at least one valid DKIM or DK signature -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 , Marc Zyngier , kernel-hardening@lists.openwall.com, Nick Desaulniers , linux-kernel@vger.kernel.org, Miguel Ojeda , Masami Hiramatsu , Sami Tolvanen , clang-built-linux@googlegroups.com, 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, restore the register before jumping back to potentially SCS 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 Acked-by: Will Deacon --- 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..6ca6c0dc11a1 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: + /* + * With CONFIG_SHADOW_CALL_STACK, the kernel uses x18 to store a + * shadow stack pointer, which we need to restore before returning to + * potentially 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 + b efi_handle_corrupted_x18 // tail call ENDPROC(__efi_rt_asm_wrapper)