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Received: from linux.microsoft.com ([13.77.154.182]) by desiato.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1tkpfv-00000002JUD-1dfb for kexec@lists.infradead.org; Wed, 19 Feb 2025 19:24:05 +0000 Received: from [10.17.64.130] (unknown [131.107.147.130]) by linux.microsoft.com (Postfix) with ESMTPSA id DEAFE2043DEA; Wed, 19 Feb 2025 11:24:00 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com DEAFE2043DEA DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1739993041; bh=zGIv90AETr+F5tSvcvrDjMjlon7SVhu4HONEQ2ljSLg=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=YmybRIfnRELUqn3fz4oLv3t+43EmM0vEAosrgZzK4zuF4kMjaRej7RQQmwZz43BbQ RoSN7K2JH38nTdaoVil/zfpSVltiGWOo/jCF3EnSKNoAREqH2Nlb1ismwyB+bkaQc2 ohrySFsliKcwZKvQmiIFDtxDfax6BW5JgHL/v5Kw= Message-ID: <6532f9e4-0c02-439d-a2d1-d3ddfa5342f3@linux.microsoft.com> Date: Wed, 19 Feb 2025 11:24:00 -0800 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v8 7/7] ima: measure kexec load and exec events as critical data To: Stefan Berger , zohar@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 Cc: madvenka@linux.microsoft.com, nramas@linux.microsoft.com, James.Bottomley@HansenPartnership.com, bhe@redhat.com, vgoyal@redhat.com, dyoung@redhat.com References: <20250218225502.747963-1-chenste@linux.microsoft.com> <20250218225502.747963-8-chenste@linux.microsoft.com> <152e2efc-732f-40bf-9aeb-6e50faa018c0@linux.ibm.com> Content-Language: en-US From: steven chen In-Reply-To: <152e2efc-732f-40bf-9aeb-6e50faa018c0@linux.ibm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250219_192404_009659_5088FD11 X-CRM114-Status: GOOD ( 20.89 ) X-BeenThere: kexec@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "kexec" Errors-To: kexec-bounces+kexec=archiver.kernel.org@lists.infradead.org On 2/19/2025 8:23 AM, Stefan Berger wrote: > > > On 2/18/25 5:55 PM, steven chen wrote: >> 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. >> >> The 'kexec_load' event IMA log can be found using the following command: >> sudo cat /sys/kernel/security/integrity/ima/ascii_runtime_measurements | >>     grep kexec_load >> >> The 'kexec_load' event IMA log can be found using the following command: >> sudo cat /sys/kernel/security/integrity/ima/ascii_runtime_measurements | >>     grep kexec_execute >> >> Signed-off-by: Tushar Sugandhi >> Signed-off-by: steven chen >> --- >>   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(+) >> >> diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h >> index 4428fcf42167..1452c98242a4 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 6c8c203ad81e..8d0782e51ffa 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 struct seq_file ima_kexec_file; >>   static void *ima_kexec_buffer; >>   static size_t kexec_segment_size; >> @@ -36,6 +38,24 @@ static void ima_free_kexec_file_buf(struct >> seq_file *sf) >>       ima_reset_kexec_file(sf); >>   } >>   +void ima_measure_kexec_event(const char *event_name) >> +{ >> +    char ima_kexec_event[IMA_KEXEC_EVENT_LEN]; >> +    size_t buf_size = 0; >> +    long len; >> + >> +    buf_size = ima_get_binary_runtime_size(); >> +    len = atomic_long_read(&ima_htable.len); >> + >> +    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); > > Indentation and n = scnprintf(...), as Mimi mentioned in v7. > >> + >> +    ima_measure_critical_data("ima_kexec", event_name, ima_kexec_event, >> +                  strlen(ima_kexec_event), false, NULL, 0); > > Replace strlen(ima_kexec_event) with 'n'. > > With these fixes: > > Reviewed-by: Stefan Berger > >> +} >> + >>   static int ima_alloc_kexec_file_buf(size_t segment_size) >>   { >>       /* >> @@ -58,6 +78,7 @@ 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 3dfd178d4292..6afb46989cf6 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; Hi Stefan, thanks for your comments. I will update in next version.