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 Received: from lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 9D7FCC43334 for ; Tue, 7 Jun 2022 19:08:13 +0000 (UTC) Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4LHfyN0TLqz3c9Z for ; Wed, 8 Jun 2022 05:08:12 +1000 (AEST) Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=gmail.com (client-ip=209.85.166.44; helo=mail-io1-f44.google.com; envelope-from=robherring2@gmail.com; receiver=) Received: from mail-io1-f44.google.com (mail-io1-f44.google.com [209.85.166.44]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4LHfxv4dDcz3bfC for ; Wed, 8 Jun 2022 05:07:46 +1000 (AEST) Received: by mail-io1-f44.google.com with SMTP id a10so16502842ioe.9 for ; Tue, 07 Jun 2022 12:07:46 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=FfDC8OCE89M5DmQOiwz11rqXI91cPiUhxnizP3Vecs4=; b=19I1I5mvwXv5syYH+DxCyfgfzlWU49q4L0Us3vXO4zxMUwBcmu0DKb6nGK1ZXgWhhH 6P0pGaWD3hgVc6hayXnmoZyu6jacsyBUlVC3v+7vExcBN1uyUS6gkdcJjzHj5fmaayxw Ex9i6LkLyrly6WF2KToe1/R0bDExEd5yaJIKRJ066dGiQqSZMRhJihjtznGz/9k+Tus5 vltLGlZLG90+n7rtU7M7YIm3Zl4/QCM1d0E2a3w7p8Pm5mLxg7pfTBpUeVmQsLV9Y2/V zz3MkMVhb6fBGXCpoAlolIV3GLi0i7NlCGkrtNFXBqfCDXpG8Qr/L2ueo17en1QZN4pK Retg== X-Gm-Message-State: AOAM530b4uQbfmy7nNF5nOxttUzB5WgGOuG0uCi9yuh7f4gBiwydhehh fBIzckdTlW1ETy5xY4nh9g== X-Google-Smtp-Source: ABdhPJyXN4BjBm3eZUFDX9fHMePl6YzIdSCERXPSC3Ydq6geCntnC7mEUdXSSQ2BbAKOjP5dYeuqbQ== X-Received: by 2002:a05:6638:160a:b0:330:f07b:7c5d with SMTP id x10-20020a056638160a00b00330f07b7c5dmr17052629jas.222.1654628863838; Tue, 07 Jun 2022 12:07:43 -0700 (PDT) Received: from robh.at.kernel.org ([64.188.179.251]) by smtp.gmail.com with ESMTPSA id k4-20020a926f04000000b002d52f2f5a97sm3143012ilc.35.2022.06.07.12.07.42 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 07 Jun 2022 12:07:43 -0700 (PDT) Received: (nullmailer pid 3646440 invoked by uid 1000); Tue, 07 Jun 2022 19:07:41 -0000 Date: Tue, 7 Jun 2022 13:07:41 -0600 From: Rob Herring To: Vaibhav Jain Subject: Re: [PATCH v3] of: check previous kernel's ima-kexec-buffer against memory bounds Message-ID: <20220607190741.GA3644258-robh@kernel.org> References: <20220531041446.3334259-1-vaibhav@linux.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220531041446.3334259-1-vaibhav@linux.ibm.com> X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: devicetree@vger.kernel.org, Frank Rowand , Ritesh Harjani , linux-kernel@vger.kernel.org, Prakhar Srivastava , Lakshmi Ramasubramanian , "Eric W. Biederman" , Thiago Jung Bauermann , Andrew Morton , Mimi Zohar , linuxppc-dev@lists.ozlabs.org, Thiago Jung Bauermann , Robin Murphy Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Tue, 31 May 2022 09:44:46 +0530, Vaibhav Jain wrote: > Presently ima_get_kexec_buffer() doesn't check if the previous kernel's > ima-kexec-buffer lies outside the addressable memory range. This can result > in a kernel panic if the new kernel is booted with 'mem=X' arg and the > ima-kexec-buffer was allocated beyond that range by the previous kernel. > The panic is usually of the form below: > > $ sudo kexec --initrd initrd vmlinux --append='mem=16G' > > > BUG: Unable to handle kernel data access on read at 0xc000c01fff7f0000 > Faulting instruction address: 0xc000000000837974 > Oops: Kernel access of bad area, sig: 11 [#1] > > NIP [c000000000837974] ima_restore_measurement_list+0x94/0x6c0 > LR [c00000000083b55c] ima_load_kexec_buffer+0xac/0x160 > Call Trace: > [c00000000371fa80] [c00000000083b55c] ima_load_kexec_buffer+0xac/0x160 > [c00000000371fb00] [c0000000020512c4] ima_init+0x80/0x108 > [c00000000371fb70] [c0000000020514dc] init_ima+0x4c/0x120 > [c00000000371fbf0] [c000000000012240] do_one_initcall+0x60/0x2c0 > [c00000000371fcc0] [c000000002004ad0] kernel_init_freeable+0x344/0x3ec > [c00000000371fda0] [c0000000000128a4] kernel_init+0x34/0x1b0 > [c00000000371fe10] [c00000000000ce64] ret_from_kernel_thread+0x5c/0x64 > Instruction dump: > f92100b8 f92100c0 90e10090 910100a0 4182050c 282a0017 3bc00000 40810330 > 7c0802a6 fb610198 7c9b2378 f80101d0 2c090001 40820614 e9240010 > ---[ end trace 0000000000000000 ]--- > > Fix this issue by checking returned PFN range of previous kernel's > ima-kexec-buffer with page_is_ram() to ensure correct memory bounds. > > Fixes: 467d27824920 ("powerpc: ima: get the kexec buffer passed by the previous kernel") > Cc: Frank Rowand > Cc: Prakhar Srivastava > Cc: Lakshmi Ramasubramanian > Cc: Thiago Jung Bauermann > Cc: Rob Herring > Cc: Ritesh Harjani > Cc: Robin Murphy > Signed-off-by: Vaibhav Jain > --- > Changelog > ========== > v3: > * change the type for {start,end}_pfn to unsigned long [ Ritesh ] > * Switched to page_is_ram() from pfn_vaild() [ Rob ] > > v2: > * Instead of using memblock to determine the valid bounds use pfn_valid() to do > so since memblock may not be available late after the kernel init. [ Mpe ] > * Changed the patch prefix from 'powerpc' to 'of' [ Mpe ] > * Updated the 'Fixes' tag to point to correct commit that introduced this > function. [ Rob ] > * Fixed some whitespace/tab issues in the patch description [ Rob ] > * Added another check for checking ig 'tmp_size' for ima-kexec-buffer is > 0 > --- > drivers/of/kexec.c | 17 +++++++++++++++++ > 1 file changed, 17 insertions(+) > Applied, thanks!