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path: root/drivers/char/tpm/tpm2_eventlog.c
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Diffstat (limited to 'drivers/char/tpm/tpm2_eventlog.c')
-rw-r--r--drivers/char/tpm/tpm2_eventlog.c203
1 files changed, 203 insertions, 0 deletions
diff --git a/drivers/char/tpm/tpm2_eventlog.c b/drivers/char/tpm/tpm2_eventlog.c
new file mode 100644
index 000000000000..513897cf9c4b
--- /dev/null
+++ b/drivers/char/tpm/tpm2_eventlog.c
@@ -0,0 +1,203 @@
+/*
+ * Copyright (C) 2016 IBM Corporation
+ *
+ * Authors:
+ * Nayna Jain <nayna@linux.vnet.ibm.com>
+ *
+ * Access to TPM 2.0 event log as written by Firmware.
+ * It assumes that writer of event log has followed TCG Specification
+ * for Family "2.0" and written the event data in little endian.
+ * With that, it doesn't need any endian conversion for structure
+ * content.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/seq_file.h>
+#include <linux/fs.h>
+#include <linux/security.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+
+#include "tpm.h"
+#include "tpm_eventlog.h"
+
+/*
+ * calc_tpm2_event_size() - calculate the event size, where event
+ * is an entry in the TPM 2.0 event log. The event is of type Crypto
+ * Agile Log Entry Format as defined in TCG EFI Protocol Specification
+ * Family "2.0".
+
+ * @event: event whose size is to be calculated.
+ * @event_header: the first event in the event log.
+ *
+ * Returns size of the event. If it is an invalid event, returns 0.
+ */
+static int calc_tpm2_event_size(struct tcg_pcr_event2 *event,
+ struct tcg_pcr_event *event_header)
+{
+ struct tcg_efi_specid_event *efispecid;
+ struct tcg_event_field *event_field;
+ void *marker;
+ void *marker_start;
+ u32 halg_size;
+ size_t size;
+ u16 halg;
+ int i;
+ int j;
+
+ marker = event;
+ marker_start = marker;
+ marker = marker + sizeof(event->pcr_idx) + sizeof(event->event_type)
+ + sizeof(event->count);
+
+ efispecid = (struct tcg_efi_specid_event *)event_header->event;
+
+ for (i = 0; (i < event->count) && (i < TPM2_ACTIVE_PCR_BANKS);
+ i++) {
+ halg_size = sizeof(event->digests[i].alg_id);
+ memcpy(&halg, marker, halg_size);
+ marker = marker + halg_size;
+ for (j = 0; (j < efispecid->num_algs); j++) {
+ if (halg == efispecid->digest_sizes[j].alg_id) {
+ marker = marker +
+ efispecid->digest_sizes[j].digest_size;
+ break;
+ }
+ }
+ }
+
+ event_field = (struct tcg_event_field *)marker;
+ marker = marker + sizeof(event_field->event_size)
+ + event_field->event_size;
+ size = marker - marker_start;
+
+ if ((event->event_type == 0) && (event_field->event_size == 0))
+ return 0;
+
+ return size;
+}
+
+static void *tpm2_bios_measurements_start(struct seq_file *m, loff_t *pos)
+{
+ struct tpm_chip *chip = m->private;
+ struct tpm_bios_log *log = &chip->log;
+ void *addr = log->bios_event_log;
+ void *limit = log->bios_event_log_end;
+ struct tcg_pcr_event *event_header;
+ struct tcg_pcr_event2 *event;
+ size_t size;
+ int i;
+
+ event_header = addr;
+ size = sizeof(struct tcg_pcr_event) - sizeof(event_header->event)
+ + event_header->event_size;
+
+ if (*pos == 0) {
+ if (addr + size < limit) {
+ if ((event_header->event_type == 0) &&
+ (event_header->event_size == 0))
+ return NULL;
+ return SEQ_START_TOKEN;
+ }
+ }
+
+ if (*pos > 0) {
+ addr += size;
+ event = addr;
+ size = calc_tpm2_event_size(event, event_header);
+ if ((addr + size >= limit) || (size == 0))
+ return NULL;
+ }
+
+ for (i = 0; i < (*pos - 1); i++) {
+ event = addr;
+ size = calc_tpm2_event_size(event, event_header);
+
+ if ((addr + size >= limit) || (size == 0))
+ return NULL;
+ addr += size;
+ }
+
+ return addr;
+}
+
+static void *tpm2_bios_measurements_next(struct seq_file *m, void *v,
+ loff_t *pos)
+{
+ struct tcg_pcr_event *event_header;
+ struct tcg_pcr_event2 *event;
+ struct tpm_chip *chip = m->private;
+ struct tpm_bios_log *log = &chip->log;
+ void *limit = log->bios_event_log_end;
+ size_t event_size;
+ void *marker;
+
+ event_header = log->bios_event_log;
+
+ if (v == SEQ_START_TOKEN) {
+ event_size = sizeof(struct tcg_pcr_event) -
+ sizeof(event_header->event) + event_header->event_size;
+ marker = event_header;
+ } else {
+ event = v;
+ event_size = calc_tpm2_event_size(event, event_header);
+ if (event_size == 0)
+ return NULL;
+ marker = event;
+ }
+
+ marker = marker + event_size;
+ if (marker >= limit)
+ return NULL;
+ v = marker;
+ event = v;
+
+ event_size = calc_tpm2_event_size(event, event_header);
+ if (((v + event_size) >= limit) || (event_size == 0))
+ return NULL;
+
+ (*pos)++;
+ return v;
+}
+
+static void tpm2_bios_measurements_stop(struct seq_file *m, void *v)
+{
+}
+
+static int tpm2_binary_bios_measurements_show(struct seq_file *m, void *v)
+{
+ struct tpm_chip *chip = m->private;
+ struct tpm_bios_log *log = &chip->log;
+ struct tcg_pcr_event *event_header = log->bios_event_log;
+ struct tcg_pcr_event2 *event = v;
+ void *temp_ptr;
+ size_t size;
+
+ if (v == SEQ_START_TOKEN) {
+ size = sizeof(struct tcg_pcr_event) -
+ sizeof(event_header->event) + event_header->event_size;
+
+ temp_ptr = event_header;
+
+ if (size > 0)
+ seq_write(m, temp_ptr, size);
+ } else {
+ size = calc_tpm2_event_size(event, event_header);
+ temp_ptr = event;
+ if (size > 0)
+ seq_write(m, temp_ptr, size);
+ }
+
+ return 0;
+}
+
+const struct seq_operations tpm2_binary_b_measurements_seqops = {
+ .start = tpm2_bios_measurements_start,
+ .next = tpm2_bios_measurements_next,
+ .stop = tpm2_bios_measurements_stop,
+ .show = tpm2_binary_bios_measurements_show,
+};