From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 64C3C1E9905; Sun, 20 Apr 2025 13:10:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=13.77.154.182 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745154629; cv=none; b=SC1R/ROERJ4lhXLAw3ezc95bnIOHoCMG5W6SdKQdHQHvkAhYO8loxWAtaLrQ97SD7wVK2W1BsvZiSE3w5tygmtvE27/rANqqu7wIeRV8Q7tk/aLONWKLmOhv3D6mRYuP8+vg/JWfvzAiHVaTJIF2lfoyYr5xt0XuklKUoqLwan0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745154629; c=relaxed/simple; bh=zNNlBENvsCMoov/hDU2BXQexFpYKj/CEPuIGt83kohw=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=Qpx3e5de93TkDWRPXhZFALrrTpqGuQM1VGSQqkh88ZohIRpL/0QJVHk0wJyhNRreEA5YOigOf0THtjpqQKX4MokaMY/wH1tKsA/0/7jzmjDff3cRMoBAioe5LmrRqN7n7th23h4TlV52mWSwyjtchozOO2x7fi5aAssexRmw5B0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.microsoft.com; spf=pass smtp.mailfrom=linux.microsoft.com; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b=pHx/vc/N; arc=none smtp.client-ip=13.77.154.182 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.microsoft.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.microsoft.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b="pHx/vc/N" Received: from [100.70.200.26] (unknown [172.200.70.35]) by linux.microsoft.com (Postfix) with ESMTPSA id DACD921165A5; Sun, 20 Apr 2025 06:10:25 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com DACD921165A5 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1745154627; bh=v8/kjfMBX5j8otcEjoEy9F00J/rSQ+ksJRgSx0LzXFY=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=pHx/vc/NZF4cnSWNIalzxFIb81vkZ06zt+dIWhi+JXx6jLz53S9tgyJir/YVKLwwf iWeQDP1iuyZ+YGDvQFdV14T7ikZPiervu0iRYlmO7wFtxh5C5uZFCkgC/WUix0HTjn EfXaB0QH27xlDR2BK3JPVWLxifSMYg3/yoqgs+A0= Message-ID: <193deea5-c1b4-4189-a5a0-a3e29841225a@linux.microsoft.com> Date: Sun, 20 Apr 2025 06:10:23 -0700 Precedence: bulk X-Mailing-List: linux-security-module@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v12 9/9] ima: measure kexec load and exec events as critical data To: Baoquan He 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 References: <20250416021028.1403-1-chenste@linux.microsoft.com> <20250416021028.1403-10-chenste@linux.microsoft.com> Content-Language: en-US From: steven chen In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 4/18/2025 2:08 AM, Baoquan He wrote: > 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 > ^^^^^ Hi Baoquan, I will add Co-developed-by tag in next version. Thanks, Steven >> 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 >>