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Diffstat (limited to 'src/libpts/pts/pts_pcr.c')
-rw-r--r-- | src/libpts/pts/pts_pcr.c | 289 |
1 files changed, 289 insertions, 0 deletions
diff --git a/src/libpts/pts/pts_pcr.c b/src/libpts/pts/pts_pcr.c new file mode 100644 index 000000000..a7a2f5fae --- /dev/null +++ b/src/libpts/pts/pts_pcr.c @@ -0,0 +1,289 @@ +/* + * Copyright (C) 2012 Andreas Steffen + * HSR Hochschule fuer Technik Rapperswil + * + * 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. See <http://www.fsf.org/copyleft/gpl.txt>. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY + * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License + * for more details. + */ + +#include "pts_pcr.h" + +#include <debug.h> + +#include <stdarg.h> + +typedef struct private_pts_pcr_t private_pts_pcr_t; + +/** + * Private data of a pts_pcr_t object. + * + */ +struct private_pts_pcr_t { + + /** + * Public pts_pcr_t interface. + */ + pts_pcr_t public; + + /** + * Shadow PCR registers + */ + chunk_t pcrs[PTS_PCR_MAX_NUM]; + + /** + * Number of extended PCR registers + */ + u_int32_t pcr_count; + + /** + * Highest extended PCR register + */ + u_int32_t pcr_max; + + /** + * Bitmap of extended PCR registers + */ + u_int8_t pcr_select[PTS_PCR_MAX_NUM / 8]; + + /** + * Hasher used to extend shadow PCRs + */ + hasher_t *hasher; + +}; + +METHOD(pts_pcr_t, get_count, u_int32_t, + private_pts_pcr_t *this) +{ + return this->pcr_count; +} + +METHOD(pts_pcr_t, select_pcr, bool, + private_pts_pcr_t *this, u_int32_t pcr) +{ + u_int32_t i, f; + + if (pcr >= PTS_PCR_MAX_NUM) + { + DBG1(DBG_PTS, "PCR %2u: number is larger than maximum of %u", + pcr, PTS_PCR_MAX_NUM-1); + return FALSE; + } + + /* Determine PCR selection flag */ + i = pcr / 8; + f = 1 << (pcr - 8*i); + + /* Has this PCR already been selected? */ + if (!(this->pcr_select[i] & f)) + { + this->pcr_select[i] |= f; + this->pcr_max = max(this->pcr_max, pcr); + this->pcr_count++; + } + return TRUE; +} + +METHOD(pts_pcr_t, get_selection_size, size_t, + private_pts_pcr_t *this) +{ + + /** + * A TPM v1.2 has 24 PCR Registers so the bitmask field length + * used by TrouSerS is at least 3 bytes + */ + return PTS_PCR_MAX_NUM / 8; +} + +typedef struct { + /** implements enumerator_t */ + enumerator_t public; + /** current PCR */ + u_int32_t pcr; + /** back reference to parent */ + private_pts_pcr_t *pcrs; +} pcr_enumerator_t; + +/** + * Implementation of enumerator.enumerate + */ +static bool pcr_enumerator_enumerate(pcr_enumerator_t *this, ...) +{ + u_int32_t *pcr, i, f; + va_list args; + + va_start(args, this); + pcr = va_arg(args, u_int32_t*); + va_end(args); + + while (this->pcr <= this->pcrs->pcr_max) + { + /* Determine PCR selection flag */ + i = this->pcr / 8; + f = 1 << (this->pcr - 8*i); + + /* Assign current PCR to output argument and increase */ + *pcr = this->pcr++; + + /* return if PCR is selected */ + if (this->pcrs->pcr_select[i] & f) + { + return TRUE; + } + } + return FALSE; +} + +METHOD(pts_pcr_t, create_enumerator, enumerator_t*, + private_pts_pcr_t *this) +{ + pcr_enumerator_t *enumerator; + + INIT(enumerator, + .public = { + .enumerate = (void*)pcr_enumerator_enumerate, + .destroy = (void*)free, + }, + .pcrs = this, + ); + + return (enumerator_t*)enumerator; +} + +METHOD(pts_pcr_t, get, chunk_t, + private_pts_pcr_t *this, u_int32_t pcr) +{ + return (pcr < PTS_PCR_MAX_NUM) ? this->pcrs[pcr] : chunk_empty; +} + +METHOD(pts_pcr_t, set, bool, + private_pts_pcr_t *this, u_int32_t pcr, chunk_t value) +{ + if (value.len != PTS_PCR_LEN) + { + DBG1(DBG_PTS, "PCR %2u: value does not fit", pcr); + return FALSE; + } + if (select_pcr(this, pcr)) + { + memcpy(this->pcrs[pcr].ptr, value.ptr, PTS_PCR_LEN); + return TRUE; + } + return FALSE; +} + +METHOD(pts_pcr_t, extend, chunk_t, + private_pts_pcr_t *this, u_int32_t pcr, chunk_t measurement) +{ + if (measurement.len != PTS_PCR_LEN) + { + DBG1(DBG_PTS, "PCR %2u: measurement does not fit", pcr); + return chunk_empty; + } + if (!select_pcr(this, pcr)) + { + return chunk_empty; + } + if (!this->hasher->get_hash(this->hasher, this->pcrs[pcr] , NULL) || + !this->hasher->get_hash(this->hasher, measurement, this->pcrs[pcr].ptr)) + { + DBG1(DBG_PTS, "PCR %2u: not extended due to hasher problem", pcr); + return chunk_empty; + } + return this->pcrs[pcr]; +} + +METHOD(pts_pcr_t, get_composite, chunk_t, + private_pts_pcr_t *this) +{ + chunk_t composite; + enumerator_t *enumerator; + u_int16_t selection_size; + u_int32_t pcr_field_size, pcr; + u_char *pos; + + selection_size = get_selection_size(this); + pcr_field_size = this->pcr_count * PTS_PCR_LEN; + + composite = chunk_alloc(2 + selection_size + 4 + pcr_field_size); + pos = composite.ptr; + htoun16(pos, selection_size); + pos += 2; + memcpy(pos, this->pcr_select, selection_size); + pos += selection_size; + htoun32(pos, pcr_field_size); + pos += 4; + + enumerator = create_enumerator(this); + while (enumerator->enumerate(enumerator, &pcr)) + { + memcpy(pos, this->pcrs[pcr].ptr, PTS_PCR_LEN); + pos += PTS_PCR_LEN; + } + enumerator->destroy(enumerator); + + DBG3(DBG_PTS, "constructed PCR Composite: %B", &composite); + return composite; +} + +METHOD(pts_pcr_t, destroy, void, + private_pts_pcr_t *this) +{ + u_int32_t i; + + for (i = 0; i < PTS_PCR_MAX_NUM; i++) + { + free(this->pcrs[i].ptr); + } + this->hasher->destroy(this->hasher); + free(this); +} + +/** + * See header + */ +pts_pcr_t *pts_pcr_create(void) +{ + private_pts_pcr_t *this; + hasher_t *hasher; + u_int32_t i; + + hasher = lib->crypto->create_hasher(lib->crypto, HASH_SHA1); + if (!hasher) + { + DBG1(DBG_PTS, "%N hasher could not be created", + hash_algorithm_short_names, HASH_SHA1); + return NULL; + } + + INIT(this, + .public = { + .get_count = _get_count, + .select_pcr = _select_pcr, + .get_selection_size = _get_selection_size, + .create_enumerator = _create_enumerator, + .get = _get, + .set = _set, + .extend = _extend, + .get_composite = _get_composite, + .destroy = _destroy, + }, + .hasher = hasher, + ); + + for (i = 0; i < PTS_PCR_MAX_NUM; i++) + { + this->pcrs[i] = chunk_alloc(PTS_PCR_LEN); + memset(this->pcrs[i].ptr, 0x00, PTS_PCR_LEN); + } + + return &this->public; +} + |