From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 98A786F2F2 for ; Fri, 18 Apr 2025 09:08:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744967300; cv=none; b=MSsR53/t671ofe2I3HwsOp0Iumr6mEE3F5MwOkDps862hD+slD/nqGYX1jcj3sOv76ia+9tBnp+kTUf+1KeK5glG3VGcz0Tw9xQQiQoH9FG/dmGjFFJXBPhAR6VMEyZam8/ijz8mJN6aTvmkoIT+o9+mAoX198lYzoIrRml53ds= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744967300; c=relaxed/simple; bh=5zEttM7G523BvZfLQt5yZk/a/I6V3yfIpylGzhsSLJ8=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Wp+BsBN7wzt+Rm0cZNunhOZvxJm3j24KuB8xn/MiF+qNKcI1+Cb0pKzOBeDc9roLN0qh2XHQfG4YT/T75m1OPw8RXrXYtRcHYKzBuUJDQ08MNbEVCs3C12oEXZLyrBdGtf6UkPp2mTcoFPi+njehlgU9W7N3dlbN7SPZCCWuXNk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=INJYjuVL; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="INJYjuVL" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1744967297; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=uRi/YC/7QKviF7pv3VzTS7PeAGEq5rIpEBd7JwQprps=; b=INJYjuVL9y9zxlFmDhh0HYM1mLS5hdSEYh36ZmILE+0kpgZ4wDwOpzJ47LHlNKn2plrlCX aoky16MS7q21b4BS0DKFKfe4UhB90DIfsWU+m83L5kqVLQBzcCfqApCGHC3G4vBNmACWuA JTuD1kGMpA7wW6bHx9+Fc5kg7rapXN8= Received: from mx-prod-mc-02.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-631-N1O5AT04PE6H56hQf3-Zog-1; Fri, 18 Apr 2025 05:08:14 -0400 X-MC-Unique: N1O5AT04PE6H56hQf3-Zog-1 X-Mimecast-MFC-AGG-ID: N1O5AT04PE6H56hQf3-Zog_1744967291 Received: from mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.40]) (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 mx-prod-mc-02.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 786B31956086; Fri, 18 Apr 2025 09:08:10 +0000 (UTC) Received: from localhost (unknown [10.72.112.33]) by mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 83CFE19560BA; Fri, 18 Apr 2025 09:08:07 +0000 (UTC) Date: Fri, 18 Apr 2025 17:08:03 +0800 From: Baoquan He To: steven chen Cc: zohar@linux.ibm.com, stefanb@linux.ibm.com, roberto.sassu@huaweicloud.com, roberto.sassu@huawei.com, eric.snowberg@oracle.com, ebiederm@xmission.com, paul@paul-moore.com, code@tyhicks.com, bauermann@kolabnow.com, linux-integrity@vger.kernel.org, kexec@lists.infradead.org, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, madvenka@linux.microsoft.com, nramas@linux.microsoft.com, James.Bottomley@hansenpartnership.com, vgoyal@redhat.com, dyoung@redhat.com Subject: Re: [PATCH v12 9/9] ima: measure kexec load and exec events as critical data Message-ID: References: <20250416021028.1403-1-chenste@linux.microsoft.com> <20250416021028.1403-10-chenste@linux.microsoft.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250416021028.1403-10-chenste@linux.microsoft.com> X-Scanned-By: MIMEDefang 3.0 on 10.30.177.40 On 04/15/25 at 07:10pm, steven chen wrote: > From: Steven Chen > > The amount of memory allocated at kexec load, even with the extra memory > allocated, might not be large enough for the entire measurement list. The > indeterminate interval between kexec 'load' and 'execute' could exacerbate > this problem. > > Define two new IMA events, 'kexec_load' and 'kexec_execute', to be > measured as critical data at kexec 'load' and 'execute' respectively. > Report the allocated kexec segment size, IMA binary log size and the > runtime measurements count as part of those events. > > These events, and the values reported through them, serve as markers in > the IMA log to verify the IMA events are captured during kexec soft > reboot. The presence of a 'kexec_load' event in between the last two > 'boot_aggregate' events in the IMA log implies this is a kexec soft > reboot, and not a cold-boot. And the absence of 'kexec_execute' event > after kexec soft reboot implies missing events in that window which > results in inconsistency with TPM PCR quotes, necessitating a cold boot > for a successful remote attestation. > > These critical data events are displayed as hex encoded ascii in the > ascii_runtime_measurement_list. Verifying the critical data hash requires > calculating the hash of the decoded ascii string. > > For example, to verify the 'kexec_load' data hash: > > sudo cat /sys/kernel/security/integrity/ima/ascii_runtime_measurements > | grep kexec_load | cut -d' ' -f 6 | xxd -r -p | sha256sum > > > To verify the 'kexec_execute' data hash: > > sudo cat /sys/kernel/security/integrity/ima/ascii_runtime_measurements > | grep kexec_execute | cut -d' ' -f 6 | xxd -r -p | sha256sum > > Signed-off-by: Tushar Sugandhi ^^^^^ > Signed-off-by: Steven Chen ^^^^^ > Reviewed-by: Mimi Zohar > --- > security/integrity/ima/ima.h | 6 ++++++ > security/integrity/ima/ima_kexec.c | 21 +++++++++++++++++++++ > security/integrity/ima/ima_queue.c | 5 +++++ > 3 files changed, 32 insertions(+) Acked-by: Baoquan He > > diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h > index 24d09ea91b87..34815baf5e21 100644 > --- a/security/integrity/ima/ima.h > +++ b/security/integrity/ima/ima.h > @@ -240,6 +240,12 @@ void ima_post_key_create_or_update(struct key *keyring, struct key *key, > unsigned long flags, bool create); > #endif > > +#ifdef CONFIG_IMA_KEXEC > +void ima_measure_kexec_event(const char *event_name); > +#else > +static inline void ima_measure_kexec_event(const char *event_name) {} > +#endif > + > /* > * The default binary_runtime_measurements list format is defined as the > * platform native format. The canonical format is defined as little-endian. > diff --git a/security/integrity/ima/ima_kexec.c b/security/integrity/ima/ima_kexec.c > index d1c9d369ba08..38cb2500f4c3 100644 > --- a/security/integrity/ima/ima_kexec.c > +++ b/security/integrity/ima/ima_kexec.c > @@ -17,6 +17,8 @@ > #include "ima.h" > > #ifdef CONFIG_IMA_KEXEC > +#define IMA_KEXEC_EVENT_LEN 256 > + > static bool ima_kexec_update_registered; > static struct seq_file ima_kexec_file; > static size_t kexec_segment_size; > @@ -31,6 +33,24 @@ static void ima_free_kexec_file_buf(struct seq_file *sf) > sf->count = 0; > } > > +void ima_measure_kexec_event(const char *event_name) > +{ > + char ima_kexec_event[IMA_KEXEC_EVENT_LEN]; > + size_t buf_size = 0; > + long len; > + int n; > + > + buf_size = ima_get_binary_runtime_size(); > + len = atomic_long_read(&ima_htable.len); > + > + n = scnprintf(ima_kexec_event, IMA_KEXEC_EVENT_LEN, > + "kexec_segment_size=%lu;ima_binary_runtime_size=%lu;" > + "ima_runtime_measurements_count=%ld;", > + kexec_segment_size, buf_size, len); > + > + ima_measure_critical_data("ima_kexec", event_name, ima_kexec_event, n, false, NULL, 0); > +} > + > static int ima_alloc_kexec_file_buf(size_t segment_size) > { > /* > @@ -53,6 +73,7 @@ static int ima_alloc_kexec_file_buf(size_t segment_size) > out: > ima_kexec_file.read_pos = 0; > ima_kexec_file.count = sizeof(struct ima_kexec_hdr); /* reserved space */ > + ima_measure_kexec_event("kexec_load"); > > return 0; > } > diff --git a/security/integrity/ima/ima_queue.c b/security/integrity/ima/ima_queue.c > index 83d53824aa98..590637e81ad1 100644 > --- a/security/integrity/ima/ima_queue.c > +++ b/security/integrity/ima/ima_queue.c > @@ -241,6 +241,11 @@ static int ima_reboot_notifier(struct notifier_block *nb, > unsigned long action, > void *data) > { > +#ifdef CONFIG_IMA_KEXEC > + if (action == SYS_RESTART && data && !strcmp(data, "kexec reboot")) > + ima_measure_kexec_event("kexec_execute"); > +#endif > + > ima_measurements_suspend(); > > return NOTIFY_DONE; > -- > 2.43.0 >