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[2620:137:e000::1:20]) by mx.google.com with ESMTP id l20-20020a170906795400b007ad69eba328si18669568ejo.539.2022.12.29.23.02.01; Thu, 29 Dec 2022 23:02:25 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@redhat.com header.s=mimecast20190719 header.b=Iuj+Sh3U; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233908AbiL3G7r (ORCPT + 99 others); Fri, 30 Dec 2022 01:59:47 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45674 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229839AbiL3G7n (ORCPT ); Fri, 30 Dec 2022 01:59:43 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 974F6140D8 for ; Thu, 29 Dec 2022 22:58:58 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1672383537; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=i6xNXZW5xcHpX8ctqGmuNcrSYwUwnLYg5NtdNPmfezg=; b=Iuj+Sh3UsyujM+7Jx8nm6hp8RFolqpvJ0KEPh6acHr/OsVyZsAYTV5DbBv641UeUgWzTEG xjsS7d+WESLIlLUPFLfdwy0DBcZotK8icE6nQ/cOVAZGS/VxuTxQzeCacjW2TpdN4A6eDc XQ9kqbTzOUmrCMlQ9Vrs4YAQCtxVuIU= Received: from mail-pf1-f200.google.com (mail-pf1-f200.google.com [209.85.210.200]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_128_GCM_SHA256) id us-mta-323-qI9O19EkPcOmJLpOHp_Bxg-1; Fri, 30 Dec 2022 01:58:56 -0500 X-MC-Unique: qI9O19EkPcOmJLpOHp_Bxg-1 Received: by mail-pf1-f200.google.com with SMTP id cp23-20020a056a00349700b005775c52dbceso10402279pfb.21 for ; Thu, 29 Dec 2022 22:58:55 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=i6xNXZW5xcHpX8ctqGmuNcrSYwUwnLYg5NtdNPmfezg=; b=yCU7gsTU3wG0B0QZNFORzokFXmW4uquH1/pfcc5HuuKSPl34qatn+Ae4UvWzlYMAT/ k35LddQAN0SsJWJJ+whIi2PAhWeY7OLELnmTMr8gRBBszsKOVQ+7PsU65qzQCz7g3h6y yFhlUKKnrnl6yk1ROBXLP1y4VAOOOYGKrYrevPvuCz1fjhnny8qVeCoEHKdI0Z9Mvl0P EcoaN9mS4Yt2Mvj7YMDxuoWxV6kXjN623/tCUFTFxSNiwN6PmWixGL5nSMPNmqxBvdb3 UAfF7JZXWWhuIF9xtvTS2eDhL0EC6kJ/U2dYILTyTOTZVkQcfUv9KVBwdXBw28KDSOJt Oc4A== X-Gm-Message-State: AFqh2krTdIYME/dNMzQdY+vO2pxIhigzWH8iaLGMgvOhACi4JTM2tL5E +Umumhq24OoEbFx9o9CgoxkDPwwZakiqMjpvuserzHp0kRFNbSbDK6FF2DhgeqBkQwnmpB7ILTx fupa8a1/+NPpKThDjAWRnsPZe X-Received: by 2002:a05:6a20:1586:b0:9d:efc0:67 with SMTP id h6-20020a056a20158600b0009defc00067mr47397754pzj.15.1672383534929; Thu, 29 Dec 2022 22:58:54 -0800 (PST) X-Received: by 2002:a05:6a20:1586:b0:9d:efc0:67 with SMTP id h6-20020a056a20158600b0009defc00067mr47397736pzj.15.1672383534644; Thu, 29 Dec 2022 22:58:54 -0800 (PST) Received: from localhost ([240e:478:10:2273:12cf:a540:d79b:db49]) by smtp.gmail.com with ESMTPSA id s5-20020aa78bc5000000b00581e0b5ad8dsm1614157pfd.107.2022.12.29.22.58.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 29 Dec 2022 22:58:54 -0800 (PST) From: Coiby Xu To: kexec@lists.infradead.org Cc: Mimi Zohar , Matthew Garrett , Jiri Bohac , David Howells , linux-integrity@vger.kernel.org, Eric Biederman , Matthew Garrett , James Morris , linux-kernel@vger.kernel.org (open list) Subject: [PATCH v3 1/2] lockdown: kexec_file: prevent unsigned kernel image when KEXEC_SIG not enabled Date: Fri, 30 Dec 2022 14:58:49 +0800 Message-Id: <20221230065850.897967-1-coxu@redhat.com> X-Mailer: git-send-email 2.38.1 MIME-Version: 1.0 X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE, RCVD_IN_MSPIKE_H2,SPF_HELO_NONE,SPF_NONE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1753621458406683451?= X-GMAIL-MSGID: =?utf-8?q?1753621458406683451?= A kernel builder may not enable KEXEC_SIG and some architectures like ppc64 simply don't have KEXEC_SIG. In these cases, unless both IMA_ARCH_POLICY and secure boot also enabled, lockdown doesn't prevent unsigned kernel image from being kexec'ed via the kexec_file_load syscall whereas it could prevent one via the kexec_load syscall. Mandate signature verification for those cases. Fixes: 155bdd30af17 ("kexec_file: Restrict at runtime if the kernel is locked down") Cc: Matthew Garrett Cc: Jiri Bohac Cc: David Howells Cc: kexec@lists.infradead.org Cc: linux-integrity@vger.kernel.org Signed-off-by: Coiby Xu Reviewed-by: Mimi Zohar --- v3 - add lockdown tests to explain why kexec_file_load failed [Mimi] v2 - collect reviewed-by tag from Mimi - s/mandate_signatute_verification/mandate_signature_verification [Mimi] - return the status of kexec_image_verify_sig correctly when signature verification is not mandated --- kernel/kexec_file.c | 26 +++++++++++++++++--------- 1 file changed, 17 insertions(+), 9 deletions(-) diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c index dd5983010b7b..2c1054ab21ef 100644 --- a/kernel/kexec_file.c +++ b/kernel/kexec_file.c @@ -125,6 +125,17 @@ void kimage_file_post_load_cleanup(struct kimage *image) image->image_loader_data = NULL; } +static bool mandate_signature_verification(void) +{ + /* + * If IMA is guaranteed to appraise a signature on the kexec + * image, permit it even if the kernel is otherwise locked + * down. + */ + return !ima_appraise_signature(READING_KEXEC_IMAGE) && + security_locked_down(LOCKDOWN_KEXEC); +} + #ifdef CONFIG_KEXEC_SIG #ifdef CONFIG_SIGNED_PE_FILE_VERIFICATION int kexec_kernel_verify_pe_sig(const char *kernel, unsigned long kernel_len) @@ -168,13 +179,7 @@ kimage_validate_signature(struct kimage *image) return ret; } - /* - * If IMA is guaranteed to appraise a signature on the kexec - * image, permit it even if the kernel is otherwise locked - * down. - */ - if (!ima_appraise_signature(READING_KEXEC_IMAGE) && - security_locked_down(LOCKDOWN_KEXEC)) + if (mandate_signature_verification()) return -EPERM; pr_debug("kernel signature verification failed (%d).\n", ret); @@ -211,10 +216,13 @@ kimage_file_prepare_segments(struct kimage *image, int kernel_fd, int initrd_fd, #ifdef CONFIG_KEXEC_SIG ret = kimage_validate_signature(image); - +#else + if (mandate_signature_verification()) + ret = -EPERM; +#endif if (ret) goto out; -#endif + /* It is possible that there no initramfs is being loaded */ if (!(flags & KEXEC_FILE_NO_INITRAMFS)) { ret = kernel_read_file_from_fd(initrd_fd, 0, &image->initrd_buf,