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danielinuxdanielinux
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Guard TPM keystore auth in check_rot
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3 files changed

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‎src/tpm.c‎

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@@ -1547,6 +1547,8 @@ int wolfBoot_check_rot(int key_slot, uint8_t* pubkey_hint)
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nv.handle.hndl = WOLFBOOT_TPM_KEYSTORE_NV_BASE + key_slot;
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#ifdef WOLFBOOT_TPM_KEYSTORE_AUTH
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nv.handle.auth.size = (UINT16)strlen(WOLFBOOT_TPM_KEYSTORE_AUTH);
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if (nv.handle.auth.size > sizeof(nv.handle.auth.buffer))
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return BAD_FUNC_ARG;
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memcpy(nv.handle.auth.buffer, WOLFBOOT_TPM_KEYSTORE_AUTH,
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nv.handle.auth.size);
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#endif

‎tools/unit-tests/Makefile‎

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@@ -50,6 +50,7 @@ TESTS:=unit-parser unit-extflash unit-string unit-spi-flash unit-aes128 \
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unit-update-disk unit-multiboot unit-boot-x86-fsp unit-qspi-flash unit-tpm-rsa-exp \
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unit-image-nopart unit-image-sha384 unit-image-sha3-384 unit-store-sbrk \
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unit-tpm-blob unit-policy-sign unit-rot-auth unit-sdhci-response-bits unit-hal-otp
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TESTS+=unit-tpm-check-rot-auth
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all: $(TESTS)
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@@ -126,6 +127,12 @@ unit-tpm-rsa-exp: ../../include/target.h unit-tpm-rsa-exp.c
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-DWOLFBOOT_HASH_SHA256 \
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-ffunction-sections -fdata-sections $(LDFLAGS) -Wl,--gc-sections
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unit-tpm-check-rot-auth: ../../include/target.h unit-tpm-check-rot-auth.c
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gcc -o $@ $^ $(CFLAGS) -I$(WOLFBOOT_LIB_WOLFTPM) -DWOLFBOOT_TPM \
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-DWOLFTPM_USER_SETTINGS -DWOLFBOOT_TPM_VERIFY -DWOLFBOOT_SIGN_RSA2048 \
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-DWOLFBOOT_HASH_SHA256 \
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-ffunction-sections -fdata-sections $(LDFLAGS) -Wl,--gc-sections
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unit-tpm-blob: ../../include/target.h unit-tpm-blob.c
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gcc -o $@ $^ $(CFLAGS) -I$(WOLFBOOT_LIB_WOLFTPM) -DWOLFBOOT_TPM \
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-DWOLFTPM_USER_SETTINGS -DWOLFBOOT_TPM_SEAL -DWOLFBOOT_SIGN_RSA2048 \

‎tools/unit-tests/unit-tpm-check-rot-auth.c‎

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@@ -0,0 +1,201 @@
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/* unit-tpm-check-rot-auth.c
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*
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* Unit tests for TPM root-of-trust auth validation.
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*/
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#include <check.h>
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#include <stdint.h>
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#include <stdio.h>
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#include <string.h>
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#ifndef SPI_CS_TPM
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#define SPI_CS_TPM 1
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#endif
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#ifndef WOLFBOOT_SHA_DIGEST_SIZE
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#define WOLFBOOT_SHA_DIGEST_SIZE 32
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#endif
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#ifndef WOLFBOOT_TPM_HASH_ALG
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#define WOLFBOOT_TPM_HASH_ALG TPM_ALG_SHA256
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#endif
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#define WOLFBOOT_TPM_KEYSTORE
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#define WOLFBOOT_TPM_KEYSTORE_AUTH \
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"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA" \
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"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
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#include "wolfboot/wolfboot.h"
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#include "keystore.h"
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#include "tpm.h"
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static uint8_t test_hdr[16];
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static uint8_t test_modulus[256];
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static uint8_t test_exponent_der[] = { 0xAA, 0x01, 0x00, 0x01, 0x7B };
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static uint8_t test_nv_digest[WOLFBOOT_SHA_DIGEST_SIZE];
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static uint32_t captured_exponent;
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int keyslot_id_by_sha(const uint8_t* pubkey_hint)
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{
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(void)pubkey_hint;
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return 0;
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}
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uint32_t keystore_get_key_type(int id)
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{
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ck_assert_int_eq(id, 0);
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return AUTH_KEY_RSA2048;
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}
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uint8_t *keystore_get_buffer(int id)
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{
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ck_assert_int_eq(id, 0);
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return test_hdr;
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}
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int keystore_get_size(int id)
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{
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ck_assert_int_eq(id, 0);
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return (int)sizeof(test_hdr);
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}
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int wc_RsaPublicKeyDecode_ex(const byte* input, word32* inOutIdx, word32 inSz,
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const byte** n, word32* nSz, const byte** e, word32* eSz)
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{
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(void)input;
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(void)inSz;
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*inOutIdx = 0;
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*n = test_modulus;
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*nSz = sizeof(test_modulus);
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*e = &test_exponent_der[1];
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*eSz = 3;
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return 0;
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}
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int wolfTPM2_LoadRsaPublicKey_ex(WOLFTPM2_DEV* dev, WOLFTPM2_KEY* key,
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const byte* rsaPub, word32 rsaPubSz, word32 exponent,
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TPM_ALG_ID scheme, TPMI_ALG_HASH hashAlg)
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{
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(void)dev;
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(void)key;
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(void)rsaPub;
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(void)rsaPubSz;
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(void)scheme;
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(void)hashAlg;
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captured_exponent = exponent;
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return 0;
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}
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int wolfTPM2_SetAuthHandle(WOLFTPM2_DEV* dev, int index,
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const WOLFTPM2_HANDLE* handle)
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{
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(void)dev;
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(void)index;
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(void)handle;
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return 0;
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}
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int wolfTPM2_SetAuthSession(WOLFTPM2_DEV* dev, int index,
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WOLFTPM2_SESSION* tpmSession, TPMA_SESSION sessionAttributes)
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{
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(void)dev;
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(void)index;
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(void)tpmSession;
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(void)sessionAttributes;
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return 0;
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}
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int wolfTPM2_UnsetAuth(WOLFTPM2_DEV* dev, int index)
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{
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(void)dev;
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(void)index;
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return 0;
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}
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int wolfTPM2_UnsetAuthSession(WOLFTPM2_DEV* dev, int index,
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WOLFTPM2_SESSION* tpmSession)
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{
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(void)dev;
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(void)index;
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(void)tpmSession;
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return 0;
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}
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int wolfTPM2_NVReadAuth(WOLFTPM2_DEV* dev, WOLFTPM2_NV* nv,
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word32 nvIndex, byte* dataBuf, word32* pDataSz, word32 offset)
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{
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(void)dev;
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(void)nv;
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(void)nvIndex;
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(void)offset;
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ck_assert_uint_eq(*pDataSz, WOLFBOOT_SHA_DIGEST_SIZE);
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memcpy(dataBuf, test_nv_digest, WOLFBOOT_SHA_DIGEST_SIZE);
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*pDataSz = WOLFBOOT_SHA_DIGEST_SIZE;
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return 0;
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}
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const char* wolfTPM2_GetRCString(int rc)
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{
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(void)rc;
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return "mock";
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}
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int ConstantCompare(const byte* a, const byte* b, int length)
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{
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int diff = 0;
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int i;
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for (i = 0; i < length; i++) {
148+
diff |= a[i] ^ b[i];
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}
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return diff;
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}
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#include "../../src/tpm.c"
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static void setup(void)
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{
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memset(test_hdr, 0x42, sizeof(test_hdr));
158+
memset(test_modulus, 0x5A, sizeof(test_modulus));
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memset(test_nv_digest, 0x7C, sizeof(test_nv_digest));
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captured_exponent = 0;
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}
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START_TEST(test_wolfBoot_check_rot_rejects_oversized_keystore_auth)
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{
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uint8_t hint[WOLFBOOT_SHA_DIGEST_SIZE];
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int rc;
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memcpy(hint, test_nv_digest, sizeof(hint));
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rc = wolfBoot_check_rot(0, hint);
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ck_assert_int_eq(rc, BAD_FUNC_ARG);
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}
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END_TEST
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static Suite *tpm_suite(void)
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{
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Suite *s;
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TCase *tc;
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s = suite_create("TPM RoT auth");
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tc = tcase_create("wolfBoot_check_rot");
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tcase_add_checked_fixture(tc, setup, NULL);
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tcase_add_test(tc, test_wolfBoot_check_rot_rejects_oversized_keystore_auth);
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suite_add_tcase(s, tc);
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return s;
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}
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int main(void)
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{
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Suite *s;
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SRunner *sr;
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int failed;
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s = tpm_suite();
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sr = srunner_create(s);
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srunner_run_all(sr, CK_NORMAL);
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failed = srunner_ntests_failed(sr);
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srunner_free(sr);
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return failed == 0 ? 0 : 1;
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}

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