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From: Matthew Garrett <matthewgarrett@google.com>
To: linux-integrity@vger.kernel.org
Cc: peterhuewe@gmx.de, jarkko.sakkinen@linux.intel.com, jgg@ziepe.ca,
	roberto.sassu@huawei.com, linux-efi@vger.kernel.org,
	linux-security-module@vger.kernel.org,
	linux-kernel@vger.kernel.org, tweek@google.com, bsz@semihalf.com,
	Matthew Garrett <mjg59@google.com>
Subject: [PATCH V6 3/4] tpm: Append the final event log to the TPM event log
Date: Fri, 17 May 2019 14:39:17 -0700
Message-ID: <20190517213918.26045-4-matthewgarrett@google.com> (raw)
In-Reply-To: <20190517213918.26045-1-matthewgarrett@google.com>

From: Matthew Garrett <mjg59@google.com>

Any events that are logged after GetEventsLog() is called are logged to
the EFI Final Events table. These events are defined as being in the
crypto agile log format, so we can just append them directly to the
existing log if it's in the same format. In theory we can also construct
old-style SHA1 log entries for devices that only return logs in that
format, but EDK2 doesn't generate the final event log in that case so
it doesn't seem worth it at the moment.

Signed-off-by: Matthew Garrett <mjg59@google.com>
Tested-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
---
 drivers/char/tpm/eventlog/efi.c | 50 ++++++++++++++++++++++++++++-----
 1 file changed, 43 insertions(+), 7 deletions(-)

diff --git a/drivers/char/tpm/eventlog/efi.c b/drivers/char/tpm/eventlog/efi.c
index 3e673ab22cb4..9179cf6bdee9 100644
--- a/drivers/char/tpm/eventlog/efi.c
+++ b/drivers/char/tpm/eventlog/efi.c
@@ -21,10 +21,13 @@
 int tpm_read_log_efi(struct tpm_chip *chip)
 {
 
+	struct efi_tcg2_final_events_table *final_tbl = NULL;
 	struct linux_efi_tpm_eventlog *log_tbl;
 	struct tpm_bios_log *log;
 	u32 log_size;
 	u8 tpm_log_version;
+	void *tmp;
+	int ret;
 
 	if (!(chip->flags & TPM_CHIP_FLAG_TPM2))
 		return -ENODEV;
@@ -52,15 +55,48 @@ int tpm_read_log_efi(struct tpm_chip *chip)
 
 	/* malloc EventLog space */
 	log->bios_event_log = kmemdup(log_tbl->log, log_size, GFP_KERNEL);
-	if (!log->bios_event_log)
-		goto err_memunmap;
-	log->bios_event_log_end = log->bios_event_log + log_size;
+	if (!log->bios_event_log) {
+		ret = -ENOMEM;
+		goto out;
+	}
 
+	log->bios_event_log_end = log->bios_event_log + log_size;
 	tpm_log_version = log_tbl->version;
-	memunmap(log_tbl);
-	return tpm_log_version;
 
-err_memunmap:
+	ret = tpm_log_version;
+
+	if (efi.tpm_final_log == EFI_INVALID_TABLE_ADDR ||
+	    efi_tpm_final_log_size == 0 ||
+	    tpm_log_version != EFI_TCG2_EVENT_LOG_FORMAT_TCG_2)
+		goto out;
+
+	final_tbl = memremap(efi.tpm_final_log,
+			     sizeof(*final_tbl) + efi_tpm_final_log_size,
+			     MEMREMAP_WB);
+	if (!final_tbl) {
+		pr_err("Could not map UEFI TPM final log\n");
+		kfree(log->bios_event_log);
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	tmp = krealloc(log->bios_event_log,
+		       log_size + efi_tpm_final_log_size,
+		       GFP_KERNEL);
+	if (!tmp) {
+		kfree(log->bios_event_log);
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	log->bios_event_log = tmp;
+	memcpy((void *)log->bios_event_log + log_size,
+	       final_tbl->events, efi_tpm_final_log_size);
+	log->bios_event_log_end = log->bios_event_log +
+		log_size + efi_tpm_final_log_size;
+
+out:
+	memunmap(final_tbl);
 	memunmap(log_tbl);
-	return -ENOMEM;
+	return ret;
 }
-- 
2.21.0.1020.gf2820cf01a-goog


  parent reply index

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-17 21:39 [PATCH V6 0/4] Add support for crypto agile TPM event logs Matthew Garrett
2019-05-17 21:39 ` [PATCH V6 1/4] tpm: Abstract crypto agile event size calculations Matthew Garrett
2019-05-17 21:39 ` [PATCH V6 2/4] tpm: Reserve the TPM final events table Matthew Garrett
2019-05-17 21:39 ` Matthew Garrett [this message]
2019-05-17 21:39 ` [PATCH V6 4/4] efi: Attempt to get the TCG2 event log in the boot stub Matthew Garrett
2019-05-18 16:12   ` Ard Biesheuvel
2019-05-20 17:37 ` [PATCH V6 0/4] Add support for crypto agile TPM event logs Bartosz Szczepanek

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