From: Mimi Zohar <zohar@linux.ibm.com>
To: Tushar Sugandhi <tusharsu@linux.microsoft.com>,
noodles@fb.com, bauermann@kolabnow.com,
kexec@lists.infradead.org, linux-integrity@vger.kernel.org
Cc: code@tyhicks.com, nramas@linux.microsoft.com, paul@paul-moore.com
Subject: Re: [PATCH 06/10] ima: update buffer at kexec execute with ima measurements
Date: Fri, 07 Jul 2023 11:01:48 -0400 [thread overview]
Message-ID: <5cd5b5efc443cbdce9dce3b121f4dbfd2db6dea3.camel@linux.ibm.com> (raw)
In-Reply-To: <20230703215709.1195644-7-tusharsu@linux.microsoft.com>
Hi Tushar,
On Mon, 2023-07-03 at 14:57 -0700, Tushar Sugandhi wrote:
> +/*
> + * Called during kexec execute so that IMA can update the measurement list.
> + */
> +static int ima_update_kexec_buffer(struct notifier_block *self,
> + unsigned long action, void *data)
> +{
> + void *new_buffer = NULL;
> + size_t new_buffer_size, cur_buffer_size;
> + bool resume = false;
> +
> + if (!kexec_in_progress) {
> + pr_info("%s: No kexec in progress.\n", __func__);
> + return NOTIFY_OK;
> + }
> +
> + if (!ima_kexec_buffer) {
> + pr_err("%s: Kexec buffer not set.\n", __func__);
> + return NOTIFY_OK;
> + }
> +
> + ima_measurements_suspend();
> +
> + cur_buffer_size = kexec_segment_size - sizeof(struct ima_kexec_hdr);
> + new_buffer_size = ima_get_binary_runtime_size();
> + if (new_buffer_size > cur_buffer_size) {
> + pr_err("%s: Measurement list grew too large.\n", __func__);
> + resume = true;
> + goto out;
> + }
This changes the current behavior of carrying as many measurements
across kexec as possible. True the measurement list won't verify
against the TPM PCRs, but not copying the measurements leaves the
impression there weren't any previous measurements.
This also explains the reason for allocating an IMA buffer (patch 1/10)
and not writing the measurements directly into the kexec buffer.
> + ima_populate_buf_at_kexec_execute(&new_buffer_size, &new_buffer);
> +
> + if (!new_buffer) {
> + pr_err("%s: Dump measurements failed.\n", __func__);
> + resume = true;
> + goto out;
> + }
> + memcpy(ima_kexec_buffer, new_buffer, new_buffer_size);
> +out:
> + kimage_unmap_segment(ima_kexec_buffer);
> + ima_kexec_buffer = NULL;
> +
> + if (resume)
> + ima_measurements_resume();
> +
> + return NOTIFY_OK;
> +}
> +
> #endif /* IMA_KEXEC */
>
> /*
--
thanks,
Mimi
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next prev parent reply other threads:[~2023-07-07 15:03 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-07-03 21:56 [PATCH 00/10] ima: measure events between kexec load and execute Tushar Sugandhi
2023-07-03 21:57 ` [PATCH 01/10] ima: implement function to allocate buffer at kexec load Tushar Sugandhi
2023-07-07 13:00 ` Mimi Zohar
2023-07-11 17:59 ` Tushar Sugandhi
2023-07-11 21:11 ` Mimi Zohar
2023-07-12 19:49 ` Tushar Sugandhi
2023-07-03 21:57 ` [PATCH 02/10] ima: implement function to populate buffer at kexec execute Tushar Sugandhi
2023-07-07 13:00 ` Mimi Zohar
2023-07-11 18:05 ` Tushar Sugandhi
2023-07-03 21:57 ` [PATCH 03/10] ima: allocate buffer at kexec load to hold ima measurements Tushar Sugandhi
2023-07-07 13:01 ` Mimi Zohar
2023-07-11 18:31 ` Tushar Sugandhi
2023-07-11 20:16 ` Stefan Berger
2023-07-12 19:39 ` Tushar Sugandhi
2023-07-03 21:57 ` [PATCH 04/10] ima: implement functions to suspend and resume measurements Tushar Sugandhi
2023-07-03 21:57 ` [PATCH 05/10] kexec: implement functions to map and unmap segment to kimage Tushar Sugandhi
2023-07-07 12:28 ` Stefan Berger
2023-07-11 18:41 ` Tushar Sugandhi
2023-07-11 19:19 ` Stefan Berger
2023-07-12 19:51 ` Tushar Sugandhi
2023-07-03 21:57 ` [PATCH 06/10] ima: update buffer at kexec execute with ima measurements Tushar Sugandhi
2023-07-07 15:01 ` Mimi Zohar [this message]
2023-07-07 19:49 ` Mimi Zohar
2023-07-11 19:08 ` Tushar Sugandhi
2023-07-12 15:45 ` Mimi Zohar
2023-07-11 19:05 ` Tushar Sugandhi
2023-07-03 21:57 ` [PATCH 07/10] ima: remove function ima_dump_measurement_list Tushar Sugandhi
2023-07-07 13:55 ` Mimi Zohar
2023-07-11 19:11 ` Tushar Sugandhi
2023-07-03 21:57 ` [PATCH 08/10] ima: implement and register a reboot notifier function to update kexec buffer Tushar Sugandhi
2023-07-03 21:57 ` [PATCH 09/10] ima: suspend measurements while the kexec buffer is being copied Tushar Sugandhi
2023-07-03 21:57 ` [PATCH 10/10] kexec: update kexec_file_load syscall to call ima_kexec_post_load Tushar Sugandhi
2023-07-07 8:20 ` RuiRui Yang
2023-07-11 19:14 ` Tushar Sugandhi
2023-07-12 1:28 ` RuiRui Yang
2023-07-12 19:30 ` Tushar Sugandhi
2023-07-07 8:18 ` [PATCH 00/10] ima: measure events between kexec load and execute Dave Young
2023-07-11 17:52 ` Tushar Sugandhi
2023-07-07 15:55 ` Mimi Zohar
2023-07-11 17:51 ` Tushar Sugandhi
2023-09-22 18:59 ` Tushar Sugandhi
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