Adding upstream version 1.12.0.upstream/1.12.0upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 391 insertions, 0 deletions

diff --git a/src/tpm.c b/src/tpm.c
new file mode 100644
index 0000000..69c48c3
--- /dev/null
+++ b/src/tpm.c
@@ -0,0 +1,391 @@
+/*
+ * Copyright (c) 2021 Yubico AB. All rights reserved.
+ * Use of this source code is governed by a BSD-style
+ * license that can be found in the LICENSE file.
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+/*
+ * Trusted Platform Module (TPM) 2.0 attestation support. Documentation
+ * references are relative to revision 01.38 of the TPM 2.0 specification.
+ */
+
+#include <openssl/sha.h>
+
+#include "packed.h"
+#include "fido.h"
+
+/* Part 1, 4.89: TPM_GENERATED_VALUE */
+#define TPM_MAGIC	0xff544347
+
+/* Part 2, 6.3: TPM_ALG_ID */
+#define TPM_ALG_RSA	0x0001
+#define TPM_ALG_SHA256	0x000b
+#define TPM_ALG_NULL	0x0010
+#define TPM_ALG_ECC	0x0023
+
+/* Part 2, 6.4: TPM_ECC_CURVE */
+#define TPM_ECC_P256	0x0003
+
+/* Part 2, 6.9: TPM_ST_ATTEST_CERTIFY */
+#define TPM_ST_CERTIFY	0x8017
+
+/* Part 2, 8.3: TPMA_OBJECT */
+#define TPMA_RESERVED	0xfff8f309	/* reserved bits; must be zero */
+#define TPMA_FIXED	0x00000002	/* object has fixed hierarchy */
+#define TPMA_CLEAR	0x00000004	/* object persists */
+#define TPMA_FIXED_P	0x00000010	/* object has fixed parent */
+#define TPMA_SENSITIVE	0x00000020	/* data originates within tpm */
+#define TPMA_SIGN	0x00040000	/* object may sign */
+
+/* Part 2, 10.4.2: TPM2B_DIGEST */
+PACKED_TYPE(tpm_sha256_digest_t,
+struct tpm_sha256_digest {
+	uint16_t size; /* sizeof(body) */
+	uint8_t  body[32];
+})
+
+/* Part 2, 10.4.3: TPM2B_DATA */
+PACKED_TYPE(tpm_sha1_data_t,
+struct tpm_sha1_data {
+	uint16_t size; /* sizeof(body */
+	uint8_t  body[20];
+})
+
+/* Part 2, 10.5.3: TPM2B_NAME */
+PACKED_TYPE(tpm_sha256_name_t,
+struct tpm_sha256_name {
+	uint16_t size; /* sizeof(alg) + sizeof(body) */
+	uint16_t alg;  /* TPM_ALG_SHA256 */
+	uint8_t  body[32];
+})
+
+/* Part 2, 10.11.1: TPMS_CLOCK_INFO */
+PACKED_TYPE(tpm_clock_info_t,
+struct tpm_clock_info {
+	uint64_t timestamp_ms;
+	uint32_t reset_count;   /* obfuscated by tpm */
+	uint32_t restart_count; /* obfuscated by tpm */
+	uint8_t  safe;          /* 1 if timestamp_ms is current */
+})
+
+/* Part 2, 10.12.8 TPMS_ATTEST */
+PACKED_TYPE(tpm_sha1_attest_t,
+struct tpm_sha1_attest {
+	uint32_t          magic;     /* TPM_MAGIC */
+	uint16_t          type;      /* TPM_ST_ATTEST_CERTIFY */
+	tpm_sha256_name_t signer;    /* full tpm path of signing key */
+	tpm_sha1_data_t   data;      /* signed sha1 */
+	tpm_clock_info_t  clock;
+	uint64_t          fwversion; /* obfuscated by tpm */
+	tpm_sha256_name_t name;      /* sha256 of tpm_rs256_pubarea_t */
+	tpm_sha256_name_t qual_name; /* full tpm path of attested key */
+})
+
+/* Part 2, 11.2.4.5: TPM2B_PUBLIC_KEY_RSA */
+PACKED_TYPE(tpm_rs256_key_t,
+struct tpm_rs256_key {
+	uint16_t size; /* sizeof(body) */
+	uint8_t  body[256];
+})
+
+/* Part 2, 11.2.5.1: TPM2B_ECC_PARAMETER */
+PACKED_TYPE(tpm_es256_coord_t,
+struct tpm_es256_coord {
+	uint16_t size; /* sizeof(body) */
+	uint8_t  body[32];
+})
+
+/* Part 2, 11.2.5.2: TPMS_ECC_POINT */
+PACKED_TYPE(tpm_es256_point_t,
+struct tpm_es256_point {
+	tpm_es256_coord_t x;
+	tpm_es256_coord_t y;
+})
+
+/* Part 2, 12.2.3.5: TPMS_RSA_PARMS */
+PACKED_TYPE(tpm_rs256_param_t,
+struct tpm_rs256_param {
+	uint16_t symmetric; /* TPM_ALG_NULL */
+	uint16_t scheme;    /* TPM_ALG_NULL */
+	uint16_t keybits;   /* 2048 */
+	uint32_t exponent;  /* zero (meaning 2^16 + 1) */
+})
+
+/* Part 2, 12.2.3.6: TPMS_ECC_PARMS */
+PACKED_TYPE(tpm_es256_param_t,
+struct tpm_es256_param {
+	uint16_t symmetric; /* TPM_ALG_NULL */
+	uint16_t scheme;    /* TPM_ALG_NULL */
+	uint16_t curve_id;  /* TPM_ECC_P256 */
+	uint16_t kdf;       /* TPM_ALG_NULL */
+})
+
+/* Part 2, 12.2.4: TPMT_PUBLIC */
+PACKED_TYPE(tpm_rs256_pubarea_t,
+struct tpm_rs256_pubarea {
+	uint16_t            alg;    /* TPM_ALG_RSA */
+	uint16_t            hash;   /* TPM_ALG_SHA256 */
+	uint32_t            attr;
+	tpm_sha256_digest_t policy; /* must be present? */
+	tpm_rs256_param_t   param;
+	tpm_rs256_key_t     key;
+})
+
+/* Part 2, 12.2.4: TPMT_PUBLIC */
+PACKED_TYPE(tpm_es256_pubarea_t,
+struct tpm_es256_pubarea {
+	uint16_t            alg;    /* TPM_ALG_ECC */
+	uint16_t            hash;   /* TPM_ALG_SHA256 */
+	uint32_t            attr;
+	tpm_sha256_digest_t policy; /* must be present? */
+	tpm_es256_param_t   param;
+	tpm_es256_point_t   point;
+})
+
+static int
+get_signed_sha1(tpm_sha1_data_t *dgst, const fido_blob_t *authdata,
+    const fido_blob_t *clientdata)
+{
+	const EVP_MD	*md = NULL;
+	EVP_MD_CTX	*ctx = NULL;
+	int		 ok = -1;
+
+	if ((dgst->size = sizeof(dgst->body)) != SHA_DIGEST_LENGTH ||
+	    (md = EVP_sha1()) == NULL ||
+	    (ctx = EVP_MD_CTX_new()) == NULL ||
+	    EVP_DigestInit_ex(ctx, md, NULL) != 1 ||
+	    EVP_DigestUpdate(ctx, authdata->ptr, authdata->len) != 1 ||
+	    EVP_DigestUpdate(ctx, clientdata->ptr, clientdata->len) != 1 ||
+	    EVP_DigestFinal_ex(ctx, dgst->body, NULL) != 1) {
+		fido_log_debug("%s: sha1", __func__);
+		goto fail;
+	}
+
+	ok = 0;
+fail:
+	EVP_MD_CTX_free(ctx);
+
+	return (ok);
+}
+
+static int
+get_signed_name(tpm_sha256_name_t *name, const fido_blob_t *pubarea)
+{
+	name->alg = TPM_ALG_SHA256;
+	name->size = sizeof(name->alg) + sizeof(name->body);
+	if (sizeof(name->body) != SHA256_DIGEST_LENGTH ||
+	    SHA256(pubarea->ptr, pubarea->len, name->body) != name->body) {
+		fido_log_debug("%s: sha256", __func__);
+		return -1;
+	}
+
+	return 0;
+}
+
+static void
+bswap_rs256_pubarea(tpm_rs256_pubarea_t *x)
+{
+	x->alg = htobe16(x->alg);
+	x->hash = htobe16(x->hash);
+	x->attr = htobe32(x->attr);
+	x->policy.size = htobe16(x->policy.size);
+	x->param.symmetric = htobe16(x->param.symmetric);
+	x->param.scheme = htobe16(x->param.scheme);
+	x->param.keybits = htobe16(x->param.keybits);
+	x->key.size = htobe16(x->key.size);
+}
+
+static void
+bswap_es256_pubarea(tpm_es256_pubarea_t *x)
+{
+	x->alg = htobe16(x->alg);
+	x->hash = htobe16(x->hash);
+	x->attr = htobe32(x->attr);
+	x->policy.size = htobe16(x->policy.size);
+	x->param.symmetric = htobe16(x->param.symmetric);
+	x->param.scheme = htobe16(x->param.scheme);
+	x->param.curve_id = htobe16(x->param.curve_id);
+	x->param.kdf = htobe16(x->param.kdf);
+	x->point.x.size = htobe16(x->point.x.size);
+	x->point.y.size = htobe16(x->point.y.size);
+}
+
+static void
+bswap_sha1_certinfo(tpm_sha1_attest_t *x)
+{
+	x->magic = htobe32(x->magic);
+	x->type = htobe16(x->type);
+	x->signer.size = htobe16(x->signer.size);
+	x->data.size = htobe16(x->data.size);
+	x->name.alg = htobe16(x->name.alg);
+	x->name.size = htobe16(x->name.size);
+}
+
+static int
+check_rs256_pubarea(const fido_blob_t *buf, const rs256_pk_t *pk)
+{
+	const tpm_rs256_pubarea_t	*actual;
+	tpm_rs256_pubarea_t		 expected;
+	int				 ok;
+
+	if (buf->len != sizeof(*actual)) {
+		fido_log_debug("%s: buf->len=%zu", __func__, buf->len);
+		return -1;
+	}
+	actual = (const void *)buf->ptr;
+
+	memset(&expected, 0, sizeof(expected));
+	expected.alg = TPM_ALG_RSA;
+	expected.hash = TPM_ALG_SHA256;
+	expected.attr = be32toh(actual->attr);
+	expected.attr &= ~(TPMA_RESERVED|TPMA_CLEAR);
+	expected.attr |= (TPMA_FIXED|TPMA_FIXED_P|TPMA_SENSITIVE|TPMA_SIGN);
+	expected.policy = actual->policy;
+	expected.policy.size = sizeof(expected.policy.body);
+	expected.param.symmetric = TPM_ALG_NULL;
+	expected.param.scheme = TPM_ALG_NULL;
+	expected.param.keybits = 2048;
+	expected.param.exponent = 0; /* meaning 2^16+1 */
+	expected.key.size = sizeof(expected.key.body);
+	memcpy(&expected.key.body, &pk->n, sizeof(expected.key.body));
+	bswap_rs256_pubarea(&expected);
+
+	ok = timingsafe_bcmp(&expected, actual, sizeof(expected));
+	explicit_bzero(&expected, sizeof(expected));
+
+	return ok != 0 ? -1 : 0;
+}
+
+static int
+check_es256_pubarea(const fido_blob_t *buf, const es256_pk_t *pk)
+{
+	const tpm_es256_pubarea_t	*actual;
+	tpm_es256_pubarea_t		 expected;
+	int				 ok;
+
+	if (buf->len != sizeof(*actual)) {
+		fido_log_debug("%s: buf->len=%zu", __func__, buf->len);
+		return -1;
+	}
+	actual = (const void *)buf->ptr;
+
+	memset(&expected, 0, sizeof(expected));
+	expected.alg = TPM_ALG_ECC;
+	expected.hash = TPM_ALG_SHA256;
+	expected.attr = be32toh(actual->attr);
+	expected.attr &= ~(TPMA_RESERVED|TPMA_CLEAR);
+	expected.attr |= (TPMA_FIXED|TPMA_FIXED_P|TPMA_SENSITIVE|TPMA_SIGN);
+	expected.policy = actual->policy;
+	expected.policy.size = sizeof(expected.policy.body);
+	expected.param.symmetric = TPM_ALG_NULL;
+	expected.param.scheme = TPM_ALG_NULL; /* TCG Alg. Registry, 5.2.4 */
+	expected.param.curve_id = TPM_ECC_P256;
+	expected.param.kdf = TPM_ALG_NULL;
+	expected.point.x.size = sizeof(expected.point.x.body);
+	expected.point.y.size = sizeof(expected.point.y.body);
+	memcpy(&expected.point.x.body, &pk->x, sizeof(expected.point.x.body));
+	memcpy(&expected.point.y.body, &pk->y, sizeof(expected.point.y.body));
+	bswap_es256_pubarea(&expected);
+
+	ok = timingsafe_bcmp(&expected, actual, sizeof(expected));
+	explicit_bzero(&expected, sizeof(expected));
+
+	return ok != 0 ? -1 : 0;
+}
+
+static int
+check_sha1_certinfo(const fido_blob_t *buf, const fido_blob_t *clientdata_hash,
+    const fido_blob_t *authdata_raw, const fido_blob_t *pubarea)
+{
+	const tpm_sha1_attest_t	*actual;
+	tpm_sha1_attest_t	 expected;
+	tpm_sha1_data_t		 signed_data;
+	tpm_sha256_name_t	 signed_name;
+	int			 ok = -1;
+
+	memset(&signed_data, 0, sizeof(signed_data));
+	memset(&signed_name, 0, sizeof(signed_name));
+
+	if (get_signed_sha1(&signed_data, authdata_raw, clientdata_hash) < 0 ||
+	    get_signed_name(&signed_name, pubarea) < 0) {
+		fido_log_debug("%s: get_signed_sha1/name", __func__);
+		goto fail;
+	}
+	if (buf->len != sizeof(*actual)) {
+		fido_log_debug("%s: buf->len=%zu", __func__, buf->len);
+		goto fail;
+	}
+	actual = (const void *)buf->ptr;
+
+	memset(&expected, 0, sizeof(expected));
+	expected.magic = TPM_MAGIC;
+	expected.type = TPM_ST_CERTIFY;
+	expected.signer = actual->signer;
+	expected.signer.size = sizeof(expected.signer.alg) +
+	    sizeof(expected.signer.body);
+	expected.data = signed_data;
+	expected.clock = actual->clock;
+	expected.clock.safe = 1;
+	expected.fwversion = actual->fwversion;
+	expected.name = signed_name;
+	expected.qual_name = actual->qual_name;
+	bswap_sha1_certinfo(&expected);
+
+	ok = timingsafe_bcmp(&expected, actual, sizeof(expected));
+fail:
+	explicit_bzero(&expected, sizeof(expected));
+	explicit_bzero(&signed_data, sizeof(signed_data));
+	explicit_bzero(&signed_name, sizeof(signed_name));
+
+	return ok != 0 ? -1 : 0;
+}
+
+int
+fido_get_signed_hash_tpm(fido_blob_t *dgst, const fido_blob_t *clientdata_hash,
+    const fido_blob_t *authdata_raw, const fido_attstmt_t *attstmt,
+    const fido_attcred_t *attcred)
+{
+	const fido_blob_t *pubarea = &attstmt->pubarea;
+	const fido_blob_t *certinfo = &attstmt->certinfo;
+
+	if (attstmt->alg != COSE_RS1) {
+		fido_log_debug("%s: unsupported alg %d", __func__,
+		    attstmt->alg);
+		return -1;
+	}
+
+	switch (attcred->type) {
+	case COSE_ES256:
+		if (check_es256_pubarea(pubarea, &attcred->pubkey.es256) < 0) {
+			fido_log_debug("%s: check_es256_pubarea", __func__);
+			return -1;
+		}
+		break;
+	case COSE_RS256:
+		if (check_rs256_pubarea(pubarea, &attcred->pubkey.rs256) < 0) {
+			fido_log_debug("%s: check_rs256_pubarea", __func__);
+			return -1;
+		}
+		break;
+	default:
+		fido_log_debug("%s: unsupported type %d", __func__,
+		    attcred->type);
+		return -1;
+	}
+
+	if (check_sha1_certinfo(certinfo, clientdata_hash, authdata_raw,
+	    pubarea) < 0) {
+		fido_log_debug("%s: check_sha1_certinfo", __func__);
+		return -1;
+	}
+
+	if (dgst->len < SHA_DIGEST_LENGTH ||
+	    SHA1(certinfo->ptr, certinfo->len, dgst->ptr) != dgst->ptr) {
+		fido_log_debug("%s: sha1", __func__);
+		return -1;
+	}
+	dgst->len = SHA_DIGEST_LENGTH;
+
+	return 0;
+}