1*0bfb2374SThiebaud Weksteen /* 2*0bfb2374SThiebaud Weksteen * Copyright (C) 2016 IBM Corporation 3*0bfb2374SThiebaud Weksteen * 4*0bfb2374SThiebaud Weksteen * Authors: 5*0bfb2374SThiebaud Weksteen * Nayna Jain <nayna@linux.vnet.ibm.com> 6*0bfb2374SThiebaud Weksteen * 7*0bfb2374SThiebaud Weksteen * Access to TPM 2.0 event log as written by Firmware. 8*0bfb2374SThiebaud Weksteen * It assumes that writer of event log has followed TCG Specification 9*0bfb2374SThiebaud Weksteen * for Family "2.0" and written the event data in little endian. 10*0bfb2374SThiebaud Weksteen * With that, it doesn't need any endian conversion for structure 11*0bfb2374SThiebaud Weksteen * content. 12*0bfb2374SThiebaud Weksteen * 13*0bfb2374SThiebaud Weksteen * This program is free software; you can redistribute it and/or 14*0bfb2374SThiebaud Weksteen * modify it under the terms of the GNU General Public License 15*0bfb2374SThiebaud Weksteen * as published by the Free Software Foundation; either version 16*0bfb2374SThiebaud Weksteen * 2 of the License, or (at your option) any later version. 17*0bfb2374SThiebaud Weksteen */ 18*0bfb2374SThiebaud Weksteen 19*0bfb2374SThiebaud Weksteen #include <linux/seq_file.h> 20*0bfb2374SThiebaud Weksteen #include <linux/fs.h> 21*0bfb2374SThiebaud Weksteen #include <linux/security.h> 22*0bfb2374SThiebaud Weksteen #include <linux/module.h> 23*0bfb2374SThiebaud Weksteen #include <linux/slab.h> 24*0bfb2374SThiebaud Weksteen #include <linux/tpm_eventlog.h> 25*0bfb2374SThiebaud Weksteen 26*0bfb2374SThiebaud Weksteen #include "../tpm.h" 27*0bfb2374SThiebaud Weksteen 28*0bfb2374SThiebaud Weksteen /* 29*0bfb2374SThiebaud Weksteen * calc_tpm2_event_size() - calculate the event size, where event 30*0bfb2374SThiebaud Weksteen * is an entry in the TPM 2.0 event log. The event is of type Crypto 31*0bfb2374SThiebaud Weksteen * Agile Log Entry Format as defined in TCG EFI Protocol Specification 32*0bfb2374SThiebaud Weksteen * Family "2.0". 33*0bfb2374SThiebaud Weksteen 34*0bfb2374SThiebaud Weksteen * @event: event whose size is to be calculated. 35*0bfb2374SThiebaud Weksteen * @event_header: the first event in the event log. 36*0bfb2374SThiebaud Weksteen * 37*0bfb2374SThiebaud Weksteen * Returns size of the event. If it is an invalid event, returns 0. 38*0bfb2374SThiebaud Weksteen */ 39*0bfb2374SThiebaud Weksteen static int calc_tpm2_event_size(struct tcg_pcr_event2 *event, 40*0bfb2374SThiebaud Weksteen struct tcg_pcr_event *event_header) 41*0bfb2374SThiebaud Weksteen { 42*0bfb2374SThiebaud Weksteen struct tcg_efi_specid_event *efispecid; 43*0bfb2374SThiebaud Weksteen struct tcg_event_field *event_field; 44*0bfb2374SThiebaud Weksteen void *marker; 45*0bfb2374SThiebaud Weksteen void *marker_start; 46*0bfb2374SThiebaud Weksteen u32 halg_size; 47*0bfb2374SThiebaud Weksteen size_t size; 48*0bfb2374SThiebaud Weksteen u16 halg; 49*0bfb2374SThiebaud Weksteen int i; 50*0bfb2374SThiebaud Weksteen int j; 51*0bfb2374SThiebaud Weksteen 52*0bfb2374SThiebaud Weksteen marker = event; 53*0bfb2374SThiebaud Weksteen marker_start = marker; 54*0bfb2374SThiebaud Weksteen marker = marker + sizeof(event->pcr_idx) + sizeof(event->event_type) 55*0bfb2374SThiebaud Weksteen + sizeof(event->count); 56*0bfb2374SThiebaud Weksteen 57*0bfb2374SThiebaud Weksteen efispecid = (struct tcg_efi_specid_event *)event_header->event; 58*0bfb2374SThiebaud Weksteen 59*0bfb2374SThiebaud Weksteen /* Check if event is malformed. */ 60*0bfb2374SThiebaud Weksteen if (event->count > efispecid->num_algs) 61*0bfb2374SThiebaud Weksteen return 0; 62*0bfb2374SThiebaud Weksteen 63*0bfb2374SThiebaud Weksteen for (i = 0; i < event->count; i++) { 64*0bfb2374SThiebaud Weksteen halg_size = sizeof(event->digests[i].alg_id); 65*0bfb2374SThiebaud Weksteen memcpy(&halg, marker, halg_size); 66*0bfb2374SThiebaud Weksteen marker = marker + halg_size; 67*0bfb2374SThiebaud Weksteen for (j = 0; j < efispecid->num_algs; j++) { 68*0bfb2374SThiebaud Weksteen if (halg == efispecid->digest_sizes[j].alg_id) { 69*0bfb2374SThiebaud Weksteen marker += 70*0bfb2374SThiebaud Weksteen efispecid->digest_sizes[j].digest_size; 71*0bfb2374SThiebaud Weksteen break; 72*0bfb2374SThiebaud Weksteen } 73*0bfb2374SThiebaud Weksteen } 74*0bfb2374SThiebaud Weksteen /* Algorithm without known length. Such event is unparseable. */ 75*0bfb2374SThiebaud Weksteen if (j == efispecid->num_algs) 76*0bfb2374SThiebaud Weksteen return 0; 77*0bfb2374SThiebaud Weksteen } 78*0bfb2374SThiebaud Weksteen 79*0bfb2374SThiebaud Weksteen event_field = (struct tcg_event_field *)marker; 80*0bfb2374SThiebaud Weksteen marker = marker + sizeof(event_field->event_size) 81*0bfb2374SThiebaud Weksteen + event_field->event_size; 82*0bfb2374SThiebaud Weksteen size = marker - marker_start; 83*0bfb2374SThiebaud Weksteen 84*0bfb2374SThiebaud Weksteen if ((event->event_type == 0) && (event_field->event_size == 0)) 85*0bfb2374SThiebaud Weksteen return 0; 86*0bfb2374SThiebaud Weksteen 87*0bfb2374SThiebaud Weksteen return size; 88*0bfb2374SThiebaud Weksteen } 89*0bfb2374SThiebaud Weksteen 90*0bfb2374SThiebaud Weksteen static void *tpm2_bios_measurements_start(struct seq_file *m, loff_t *pos) 91*0bfb2374SThiebaud Weksteen { 92*0bfb2374SThiebaud Weksteen struct tpm_chip *chip = m->private; 93*0bfb2374SThiebaud Weksteen struct tpm_bios_log *log = &chip->log; 94*0bfb2374SThiebaud Weksteen void *addr = log->bios_event_log; 95*0bfb2374SThiebaud Weksteen void *limit = log->bios_event_log_end; 96*0bfb2374SThiebaud Weksteen struct tcg_pcr_event *event_header; 97*0bfb2374SThiebaud Weksteen struct tcg_pcr_event2 *event; 98*0bfb2374SThiebaud Weksteen size_t size; 99*0bfb2374SThiebaud Weksteen int i; 100*0bfb2374SThiebaud Weksteen 101*0bfb2374SThiebaud Weksteen event_header = addr; 102*0bfb2374SThiebaud Weksteen size = sizeof(struct tcg_pcr_event) - sizeof(event_header->event) 103*0bfb2374SThiebaud Weksteen + event_header->event_size; 104*0bfb2374SThiebaud Weksteen 105*0bfb2374SThiebaud Weksteen if (*pos == 0) { 106*0bfb2374SThiebaud Weksteen if (addr + size < limit) { 107*0bfb2374SThiebaud Weksteen if ((event_header->event_type == 0) && 108*0bfb2374SThiebaud Weksteen (event_header->event_size == 0)) 109*0bfb2374SThiebaud Weksteen return NULL; 110*0bfb2374SThiebaud Weksteen return SEQ_START_TOKEN; 111*0bfb2374SThiebaud Weksteen } 112*0bfb2374SThiebaud Weksteen } 113*0bfb2374SThiebaud Weksteen 114*0bfb2374SThiebaud Weksteen if (*pos > 0) { 115*0bfb2374SThiebaud Weksteen addr += size; 116*0bfb2374SThiebaud Weksteen event = addr; 117*0bfb2374SThiebaud Weksteen size = calc_tpm2_event_size(event, event_header); 118*0bfb2374SThiebaud Weksteen if ((addr + size >= limit) || (size == 0)) 119*0bfb2374SThiebaud Weksteen return NULL; 120*0bfb2374SThiebaud Weksteen } 121*0bfb2374SThiebaud Weksteen 122*0bfb2374SThiebaud Weksteen for (i = 0; i < (*pos - 1); i++) { 123*0bfb2374SThiebaud Weksteen event = addr; 124*0bfb2374SThiebaud Weksteen size = calc_tpm2_event_size(event, event_header); 125*0bfb2374SThiebaud Weksteen 126*0bfb2374SThiebaud Weksteen if ((addr + size >= limit) || (size == 0)) 127*0bfb2374SThiebaud Weksteen return NULL; 128*0bfb2374SThiebaud Weksteen addr += size; 129*0bfb2374SThiebaud Weksteen } 130*0bfb2374SThiebaud Weksteen 131*0bfb2374SThiebaud Weksteen return addr; 132*0bfb2374SThiebaud Weksteen } 133*0bfb2374SThiebaud Weksteen 134*0bfb2374SThiebaud Weksteen static void *tpm2_bios_measurements_next(struct seq_file *m, void *v, 135*0bfb2374SThiebaud Weksteen loff_t *pos) 136*0bfb2374SThiebaud Weksteen { 137*0bfb2374SThiebaud Weksteen struct tcg_pcr_event *event_header; 138*0bfb2374SThiebaud Weksteen struct tcg_pcr_event2 *event; 139*0bfb2374SThiebaud Weksteen struct tpm_chip *chip = m->private; 140*0bfb2374SThiebaud Weksteen struct tpm_bios_log *log = &chip->log; 141*0bfb2374SThiebaud Weksteen void *limit = log->bios_event_log_end; 142*0bfb2374SThiebaud Weksteen size_t event_size; 143*0bfb2374SThiebaud Weksteen void *marker; 144*0bfb2374SThiebaud Weksteen 145*0bfb2374SThiebaud Weksteen event_header = log->bios_event_log; 146*0bfb2374SThiebaud Weksteen 147*0bfb2374SThiebaud Weksteen if (v == SEQ_START_TOKEN) { 148*0bfb2374SThiebaud Weksteen event_size = sizeof(struct tcg_pcr_event) - 149*0bfb2374SThiebaud Weksteen sizeof(event_header->event) + event_header->event_size; 150*0bfb2374SThiebaud Weksteen marker = event_header; 151*0bfb2374SThiebaud Weksteen } else { 152*0bfb2374SThiebaud Weksteen event = v; 153*0bfb2374SThiebaud Weksteen event_size = calc_tpm2_event_size(event, event_header); 154*0bfb2374SThiebaud Weksteen if (event_size == 0) 155*0bfb2374SThiebaud Weksteen return NULL; 156*0bfb2374SThiebaud Weksteen marker = event; 157*0bfb2374SThiebaud Weksteen } 158*0bfb2374SThiebaud Weksteen 159*0bfb2374SThiebaud Weksteen marker = marker + event_size; 160*0bfb2374SThiebaud Weksteen if (marker >= limit) 161*0bfb2374SThiebaud Weksteen return NULL; 162*0bfb2374SThiebaud Weksteen v = marker; 163*0bfb2374SThiebaud Weksteen event = v; 164*0bfb2374SThiebaud Weksteen 165*0bfb2374SThiebaud Weksteen event_size = calc_tpm2_event_size(event, event_header); 166*0bfb2374SThiebaud Weksteen if (((v + event_size) >= limit) || (event_size == 0)) 167*0bfb2374SThiebaud Weksteen return NULL; 168*0bfb2374SThiebaud Weksteen 169*0bfb2374SThiebaud Weksteen (*pos)++; 170*0bfb2374SThiebaud Weksteen return v; 171*0bfb2374SThiebaud Weksteen } 172*0bfb2374SThiebaud Weksteen 173*0bfb2374SThiebaud Weksteen static void tpm2_bios_measurements_stop(struct seq_file *m, void *v) 174*0bfb2374SThiebaud Weksteen { 175*0bfb2374SThiebaud Weksteen } 176*0bfb2374SThiebaud Weksteen 177*0bfb2374SThiebaud Weksteen static int tpm2_binary_bios_measurements_show(struct seq_file *m, void *v) 178*0bfb2374SThiebaud Weksteen { 179*0bfb2374SThiebaud Weksteen struct tpm_chip *chip = m->private; 180*0bfb2374SThiebaud Weksteen struct tpm_bios_log *log = &chip->log; 181*0bfb2374SThiebaud Weksteen struct tcg_pcr_event *event_header = log->bios_event_log; 182*0bfb2374SThiebaud Weksteen struct tcg_pcr_event2 *event = v; 183*0bfb2374SThiebaud Weksteen void *temp_ptr; 184*0bfb2374SThiebaud Weksteen size_t size; 185*0bfb2374SThiebaud Weksteen 186*0bfb2374SThiebaud Weksteen if (v == SEQ_START_TOKEN) { 187*0bfb2374SThiebaud Weksteen size = sizeof(struct tcg_pcr_event) - 188*0bfb2374SThiebaud Weksteen sizeof(event_header->event) + event_header->event_size; 189*0bfb2374SThiebaud Weksteen 190*0bfb2374SThiebaud Weksteen temp_ptr = event_header; 191*0bfb2374SThiebaud Weksteen 192*0bfb2374SThiebaud Weksteen if (size > 0) 193*0bfb2374SThiebaud Weksteen seq_write(m, temp_ptr, size); 194*0bfb2374SThiebaud Weksteen } else { 195*0bfb2374SThiebaud Weksteen size = calc_tpm2_event_size(event, event_header); 196*0bfb2374SThiebaud Weksteen temp_ptr = event; 197*0bfb2374SThiebaud Weksteen if (size > 0) 198*0bfb2374SThiebaud Weksteen seq_write(m, temp_ptr, size); 199*0bfb2374SThiebaud Weksteen } 200*0bfb2374SThiebaud Weksteen 201*0bfb2374SThiebaud Weksteen return 0; 202*0bfb2374SThiebaud Weksteen } 203*0bfb2374SThiebaud Weksteen 204*0bfb2374SThiebaud Weksteen const struct seq_operations tpm2_binary_b_measurements_seqops = { 205*0bfb2374SThiebaud Weksteen .start = tpm2_bios_measurements_start, 206*0bfb2374SThiebaud Weksteen .next = tpm2_bios_measurements_next, 207*0bfb2374SThiebaud Weksteen .stop = tpm2_bios_measurements_stop, 208*0bfb2374SThiebaud Weksteen .show = tpm2_binary_bios_measurements_show, 209*0bfb2374SThiebaud Weksteen }; 210