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 15:49:42 -0400 [thread overview] Message-ID: <a3f141d0585580676e6738ff6596dad106f7bf18.camel@linux.ibm.com> (raw) In-Reply-To: <5cd5b5efc443cbdce9dce3b121f4dbfd2db6dea3.camel@linux.ibm.com> On Fri, 2023-07-07 at 11:01 -0400, Mimi Zohar wrote: > 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. If not carrying even a partial measurement list across kexec is desired, then in addition to the "boot_aggregate" record, define a new record containing the TPM pcrcounter. With this information, attestation servers will at least be able to detect if the measurement list was truncated. thanks, Mimi > > > + 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 */ > > > > /* >
WARNING: multiple messages have this Message-ID (diff)
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 15:49:42 -0400 [thread overview] Message-ID: <a3f141d0585580676e6738ff6596dad106f7bf18.camel@linux.ibm.com> (raw) In-Reply-To: <5cd5b5efc443cbdce9dce3b121f4dbfd2db6dea3.camel@linux.ibm.com> On Fri, 2023-07-07 at 11:01 -0400, Mimi Zohar wrote: > 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. If not carrying even a partial measurement list across kexec is desired, then in addition to the "boot_aggregate" record, define a new record containing the TPM pcrcounter. With this information, attestation servers will at least be able to detect if the measurement list was truncated. thanks, Mimi > > > + 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 */ > > > > /* > _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec
next prev parent reply other threads:[~2023-07-07 19:50 UTC|newest] Thread overview: 82+ 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 21:56 ` Tushar Sugandhi 2023-07-03 21:57 ` [PATCH 01/10] ima: implement function to allocate buffer at kexec load Tushar Sugandhi 2023-07-03 21:57 ` Tushar Sugandhi 2023-07-07 13:00 ` Mimi Zohar 2023-07-07 13:00 ` Mimi Zohar 2023-07-11 17:59 ` Tushar Sugandhi 2023-07-11 17:59 ` Tushar Sugandhi 2023-07-11 21:11 ` Mimi Zohar 2023-07-11 21:11 ` Mimi Zohar 2023-07-12 19:49 ` Tushar Sugandhi 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 2023-07-03 21:57 ` Tushar Sugandhi 2023-07-07 13:00 ` Mimi Zohar 2023-07-07 13:00 ` Mimi Zohar 2023-07-11 18:05 ` Tushar Sugandhi 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 2023-07-03 21:57 ` Tushar Sugandhi 2023-07-07 13:01 ` Mimi Zohar 2023-07-07 13:01 ` Mimi Zohar 2023-07-11 18:31 ` Tushar Sugandhi 2023-07-11 18:31 ` Tushar Sugandhi 2023-07-11 20:16 ` Stefan Berger 2023-07-11 20:16 ` Stefan Berger 2023-07-12 19:39 ` Tushar Sugandhi 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 ` Tushar Sugandhi 2023-07-03 21:57 ` [PATCH 05/10] kexec: implement functions to map and unmap segment to kimage Tushar Sugandhi 2023-07-03 21:57 ` Tushar Sugandhi 2023-07-07 12:28 ` Stefan Berger 2023-07-07 12:28 ` Stefan Berger 2023-07-11 18:41 ` Tushar Sugandhi 2023-07-11 18:41 ` Tushar Sugandhi 2023-07-11 19:19 ` Stefan Berger 2023-07-11 19:19 ` Stefan Berger 2023-07-12 19:51 ` Tushar Sugandhi 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 2023-07-03 21:57 ` Tushar Sugandhi 2023-07-07 15:01 ` Mimi Zohar 2023-07-07 15:01 ` Mimi Zohar 2023-07-07 19:49 ` Mimi Zohar [this message] 2023-07-07 19:49 ` Mimi Zohar 2023-07-11 19:08 ` Tushar Sugandhi 2023-07-11 19:08 ` Tushar Sugandhi 2023-07-12 15:45 ` Mimi Zohar 2023-07-12 15:45 ` Mimi Zohar 2023-07-11 19:05 ` Tushar Sugandhi 2023-07-11 19:05 ` Tushar Sugandhi 2023-07-03 21:57 ` [PATCH 07/10] ima: remove function ima_dump_measurement_list Tushar Sugandhi 2023-07-03 21:57 ` Tushar Sugandhi 2023-07-07 13:55 ` Mimi Zohar 2023-07-07 13:55 ` Mimi Zohar 2023-07-11 19:11 ` Tushar Sugandhi 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 ` 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 ` Tushar Sugandhi 2023-07-03 21:57 ` [PATCH 10/10] kexec: update kexec_file_load syscall to call ima_kexec_post_load Tushar Sugandhi 2023-07-03 21:57 ` Tushar Sugandhi 2023-07-07 8:20 ` RuiRui Yang 2023-07-07 8:20 ` RuiRui Yang 2023-07-11 19:14 ` Tushar Sugandhi 2023-07-11 19:14 ` Tushar Sugandhi 2023-07-12 1:28 ` RuiRui Yang 2023-07-12 1:28 ` RuiRui Yang 2023-07-12 19:30 ` Tushar Sugandhi 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 2023-07-07 8:18 ` Dave Young 2023-07-11 17:52 ` Tushar Sugandhi 2023-07-11 17:52 ` Tushar Sugandhi 2023-07-07 15:55 ` Mimi Zohar 2023-07-07 15:55 ` Mimi Zohar 2023-07-11 17:51 ` Tushar Sugandhi 2023-07-11 17:51 ` Tushar Sugandhi 2023-09-22 18:59 ` Tushar Sugandhi 2023-09-22 18:59 ` Tushar Sugandhi
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