tpm2: add tpm2_policy_pcr()

This adds functions to get the digest for a PolicyPCR operation. For building
a policy hash, this provides a function to calculate the hash; and for building
a policy hash to satisfy the authPolicy for an existing object, this provides a
function to perform PolicyPCR with an existing session.

diff --git a/src/shared/tpm2-util.c b/src/shared/tpm2-util.c
index 5e52191dd80fae82864d5213a80742e495a1e565..48f6ce3d72088c8ef11f10276b7e0cf7fc7d5967 100644 (file)
--- a/src/shared/tpm2-util.c
+++ b/src/shared/tpm2-util.c
@@ -64,10 +64,12 @@ TSS2_RC (*sym_Esys_VerifySignature)(ESYS_CONTEXT *esysContext, ESYS_TR keyHandle
 
 const char* (*sym_Tss2_RC_Decode)(TSS2_RC rc) = NULL;
 
+TSS2_RC (*sym_Tss2_MU_TPM2_CC_Marshal)(TPM2_CC src, uint8_t buffer[], size_t buffer_size, size_t *offset) = NULL;
 TSS2_RC (*sym_Tss2_MU_TPM2B_PRIVATE_Marshal)(TPM2B_PRIVATE const *src, uint8_t buffer[], size_t buffer_size, size_t *offset) = NULL;
 TSS2_RC (*sym_Tss2_MU_TPM2B_PRIVATE_Unmarshal)(uint8_t const buffer[], size_t buffer_size, size_t *offset, TPM2B_PRIVATE  *dest) = NULL;
 TSS2_RC (*sym_Tss2_MU_TPM2B_PUBLIC_Marshal)(TPM2B_PUBLIC const *src, uint8_t buffer[], size_t buffer_size, size_t *offset) = NULL;
 TSS2_RC (*sym_Tss2_MU_TPM2B_PUBLIC_Unmarshal)(uint8_t const buffer[], size_t buffer_size, size_t *offset, TPM2B_PUBLIC *dest) = NULL;
+TSS2_RC (*sym_Tss2_MU_TPML_PCR_SELECTION_Marshal)(TPML_PCR_SELECTION const *src, uint8_t buffer[], size_t buffer_size, size_t *offset) = NULL;
 TSS2_RC (*sym_Tss2_MU_TPMT_HA_Marshal)(TPMT_HA const *src, uint8_t buffer[], size_t buffer_size, size_t *offset) = NULL;
 TSS2_RC (*sym_Tss2_MU_TPMT_PUBLIC_Marshal)(TPMT_PUBLIC const *src, uint8_t buffer[], size_t buffer_size, size_t *offset) = NULL;
 
@@ -116,10 +118,12 @@ int dlopen_tpm2(void) {
 
         return dlopen_many_sym_or_warn(
                         &libtss2_mu_dl, "libtss2-mu.so.0", LOG_DEBUG,
+                        DLSYM_ARG(Tss2_MU_TPM2_CC_Marshal),
                         DLSYM_ARG(Tss2_MU_TPM2B_PRIVATE_Marshal),
                         DLSYM_ARG(Tss2_MU_TPM2B_PRIVATE_Unmarshal),
                         DLSYM_ARG(Tss2_MU_TPM2B_PUBLIC_Marshal),
                         DLSYM_ARG(Tss2_MU_TPM2B_PUBLIC_Unmarshal),
+                        DLSYM_ARG(Tss2_MU_TPML_PCR_SELECTION_Marshal),
                         DLSYM_ARG(Tss2_MU_TPMT_HA_Marshal),
                         DLSYM_ARG(Tss2_MU_TPMT_PUBLIC_Marshal));
 }
@@ -1929,6 +1933,90 @@ static int tpm2_get_name(
         return 0;
 }
 
+/* Extend 'digest' with the PolicyPCR calculated hash. */
+int tpm2_calculate_policy_pcr(
+                const TPML_PCR_SELECTION *pcr_selection,
+                const TPM2B_DIGEST pcr_values[],
+                size_t n_pcr_values,
+                TPM2B_DIGEST *digest) {
+
+        TPM2_CC command = TPM2_CC_PolicyPCR;
+        TSS2_RC rc;
+        int r;
+
+        assert(pcr_selection);
+        assert(pcr_values || n_pcr_values == 0);
+        assert(digest);
+        assert(digest->size == SHA256_DIGEST_SIZE);
+
+        r = dlopen_tpm2();
+        if (r < 0)
+                return log_error_errno(r, "TPM2 support not installed: %m");
+
+        TPM2B_DIGEST hash = {};
+        r = tpm2_digest_many_digests(TPM2_ALG_SHA256, &hash, pcr_values, n_pcr_values, /* extend= */ false);
+        if (r < 0)
+                return r;
+
+        _cleanup_free_ uint8_t *buf = NULL;
+        size_t size = 0, maxsize = sizeof(command) + sizeof(*pcr_selection);
+
+        buf = malloc(maxsize);
+        if (!buf)
+                return log_oom();
+
+        rc = sym_Tss2_MU_TPM2_CC_Marshal(command, buf, maxsize, &size);
+        if (rc != TSS2_RC_SUCCESS)
+                return log_error_errno(SYNTHETIC_ERRNO(ENOTRECOVERABLE),
+                                       "Failed to marshal PolicyPCR command: %s", sym_Tss2_RC_Decode(rc));
+
+        rc = sym_Tss2_MU_TPML_PCR_SELECTION_Marshal(pcr_selection, buf, maxsize, &size);
+        if (rc != TSS2_RC_SUCCESS)
+                return log_error_errno(SYNTHETIC_ERRNO(ENOTRECOVERABLE),
+                                       "Failed to marshal PCR selection: %s", sym_Tss2_RC_Decode(rc));
+
+        struct iovec data[] = {
+                IOVEC_MAKE(buf, size),
+                IOVEC_MAKE(hash.buffer, hash.size),
+        };
+        r = tpm2_digest_many(TPM2_ALG_SHA256, digest, data, ELEMENTSOF(data), /* extend= */ true);
+        if (r < 0)
+                return r;
+
+        tpm2_log_debug_digest(digest, "PolicyPCR calculated digest");
+
+        return 0;
+}
+
+static int tpm2_policy_pcr(
+                Tpm2Context *c,
+                const Tpm2Handle *session,
+                const TPML_PCR_SELECTION *pcr_selection,
+                TPM2B_DIGEST **ret_policy_digest) {
+
+        TSS2_RC rc;
+
+        assert(c);
+        assert(session);
+        assert(pcr_selection);
+
+        log_debug("Adding PCR hash policy.");
+
+        rc = sym_Esys_PolicyPCR(
+                        c->esys_context,
+                        session->esys_handle,
+                        ESYS_TR_NONE,
+                        ESYS_TR_NONE,
+                        ESYS_TR_NONE,
+                        NULL,
+                        pcr_selection);
+        if (rc != TSS2_RC_SUCCESS)
+                return log_error_errno(SYNTHETIC_ERRNO(ENOTRECOVERABLE),
+                                       "Failed to add PCR policy to TPM: %s", sym_Tss2_RC_Decode(rc));
+
+        return tpm2_get_policy_digest(c, session, ret_policy_digest);
+}
+
 static int tpm2_build_sealing_policy(
                 Tpm2Context *c,
                 const Tpm2Handle *session,
@@ -2004,21 +2092,8 @@ static int tpm2_build_sealing_policy(
                 /* Put together the PCR policy we want to use */
                 TPML_PCR_SELECTION pcr_selection;
                 tpm2_tpml_pcr_selection_from_mask(pubkey_pcr_mask, (TPMI_ALG_HASH)pcr_bank, &pcr_selection);
-                rc = sym_Esys_PolicyPCR(
-                                c->esys_context,
-                                session->esys_handle,
-                                ESYS_TR_NONE,
-                                ESYS_TR_NONE,
-                                ESYS_TR_NONE,
-                                NULL,
-                                &pcr_selection);
-                if (rc != TSS2_RC_SUCCESS)
-                        return log_error_errno(SYNTHETIC_ERRNO(ENOTRECOVERABLE),
-                                               "Failed to add PCR policy to TPM: %s", sym_Tss2_RC_Decode(rc));
-
-                /* Get the policy hash of the PCR policy */
                 _cleanup_(Esys_Freep) TPM2B_DIGEST *approved_policy = NULL;
-                r = tpm2_get_policy_digest(c, session, &approved_policy);
+                r = tpm2_policy_pcr(c, session, &pcr_selection, &approved_policy);
                 if (r < 0)
                         return r;
 
@@ -2098,21 +2173,11 @@ static int tpm2_build_sealing_policy(
         }
 
         if (hash_pcr_mask != 0) {
-                log_debug("Configuring hash-based PCR policy.");
-
                 TPML_PCR_SELECTION pcr_selection;
                 tpm2_tpml_pcr_selection_from_mask(hash_pcr_mask, (TPMI_ALG_HASH)pcr_bank, &pcr_selection);
-                rc = sym_Esys_PolicyPCR(
-                                c->esys_context,
-                                session->esys_handle,
-                                ESYS_TR_NONE,
-                                ESYS_TR_NONE,
-                                ESYS_TR_NONE,
-                                NULL,
-                                &pcr_selection);
-                if (rc != TSS2_RC_SUCCESS)
-                        return log_error_errno(SYNTHETIC_ERRNO(ENOTRECOVERABLE),
-                                               "Failed to add PCR policy to TPM: %s", sym_Tss2_RC_Decode(rc));
+                r = tpm2_policy_pcr(c, session, &pcr_selection, NULL);
+                if (r < 0)
+                        return r;
         }
 
         if (use_pin) {

diff --git a/src/shared/tpm2-util.h b/src/shared/tpm2-util.h
index 12aad22a0f0b6f85fcb5be129b3723aada59e085..3028d95c0545998072a7019546aa5f761b710f45 100644 (file)
--- a/src/shared/tpm2-util.h
+++ b/src/shared/tpm2-util.h
@@ -66,10 +66,12 @@ extern TSS2_RC (*sym_Esys_VerifySignature)(ESYS_CONTEXT *esysContext, ESYS_TR ke
 
 extern const char* (*sym_Tss2_RC_Decode)(TSS2_RC rc);
 
+extern TSS2_RC (*sym_Tss2_MU_TPM2_CC_Marshal)(TPM2_CC src, uint8_t buffer[], size_t buffer_size, size_t *offset);
 extern TSS2_RC (*sym_Tss2_MU_TPM2B_PRIVATE_Marshal)(TPM2B_PRIVATE const *src, uint8_t buffer[], size_t buffer_size, size_t *offset);
 extern TSS2_RC (*sym_Tss2_MU_TPM2B_PRIVATE_Unmarshal)(uint8_t const buffer[], size_t buffer_size, size_t *offset, TPM2B_PRIVATE  *dest);
 extern TSS2_RC (*sym_Tss2_MU_TPM2B_PUBLIC_Marshal)(TPM2B_PUBLIC const *src, uint8_t buffer[], size_t buffer_size, size_t *offset);
 extern TSS2_RC (*sym_Tss2_MU_TPM2B_PUBLIC_Unmarshal)(uint8_t const buffer[], size_t buffer_size, size_t *offset, TPM2B_PUBLIC *dest);
+extern TSS2_RC (*sym_Tss2_MU_TPML_PCR_SELECTION_Marshal)(TPML_PCR_SELECTION const *src, uint8_t buffer[], size_t buffer_size, size_t *offset);
 extern TSS2_RC (*sym_Tss2_MU_TPMT_HA_Marshal)(TPMT_HA const *src, uint8_t buffer[], size_t buffer_size, size_t *offset);
 extern TSS2_RC (*sym_Tss2_MU_TPMT_PUBLIC_Marshal)(TPMT_PUBLIC const *src, uint8_t buffer[], size_t buffer_size, size_t *offset);
 
@@ -88,6 +90,7 @@ static inline int tpm2_digest_init(TPMI_ALG_HASH alg, TPM2B_DIGEST *digest) {
 }
 
 int tpm2_calculate_name(const TPMT_PUBLIC *public, TPM2B_NAME *ret_name);
+int tpm2_calculate_policy_pcr(const TPML_PCR_SELECTION *pcr_selection, const TPM2B_DIGEST pcr_values[], size_t pcr_values_count, TPM2B_DIGEST *digest);
 
 int tpm2_seal(const char *device, uint32_t hash_pcr_mask, const void *pubkey, size_t pubkey_size, uint32_t pubkey_pcr_mask, const char *pin, void **ret_secret, size_t *ret_secret_size, void **ret_blob, size_t *ret_blob_size, void **ret_pcr_hash, size_t *ret_pcr_hash_size, uint16_t *ret_pcr_bank, uint16_t *ret_primary_alg, void **ret_srk_buf, size_t *ret_srk_buf_size);
 int tpm2_unseal(const char *device, uint32_t hash_pcr_mask, uint16_t pcr_bank, const void *pubkey, size_t pubkey_size, uint32_t pubkey_pcr_mask, JsonVariant *signature, const char *pin, uint16_t primary_alg, const void *blob, size_t blob_size, const void *policy_hash, size_t policy_hash_size, const void *srk_buf, size_t srk_buf_size, void **ret_secret, size_t *ret_secret_size);

diff --git a/src/test/test-tpm2.c b/src/test/test-tpm2.c
index df64a4a106ac6da7f007a50d80f194b43a3fe764..6542b9cf9f7b78dfb441d1b1cecf94401e8bb503 100644 (file)
--- a/src/test/test-tpm2.c
+++ b/src/test/test-tpm2.c
@@ -690,6 +690,54 @@ TEST(calculate_name) {
         assert_se(streq(expect, h));
 }
 
+TEST(calculate_policy_pcr) {
+        TPML_PCR_SELECTION pcr_selection;
+        TPM2B_DIGEST pcr_values[16];
+        TPM2B_DIGEST d;
+        uint32_t pcr_mask;
+
+        digest_init_sha256(&d, "0000000000000000000000000000000000000000000000000000000000000000");
+        pcr_mask = (1<<4) | (1<<7) | (1<<8);
+        tpm2_tpml_pcr_selection_from_mask(pcr_mask, TPM2_ALG_SHA256, &pcr_selection);
+        digest_init_sha256(&pcr_values[0], "368f85b3013041dfe203faaa364f00b07c5da7b1e5f1dbf2efb06fa6b9bd92de");
+        digest_init_sha256(&pcr_values[1], "aa1154c9e0a774854ccbed4c8ce7e9b906b3d700a1a8db1772d0341a62dbe51b");
+        digest_init_sha256(&pcr_values[2], "cfde439a2c06af3479ca6bdc60429b90553d65300c5cfcc40004a08c6b5ad81a");
+        assert_se(tpm2_calculate_policy_pcr(&pcr_selection, pcr_values, 3, &d) == 0);
+        assert_se(digest_check(&d, "76532a0e16f7e6bf6b02918c11f75d99d729fab0cc81d0df2c4284a2c4fe6e05"));
+
+        pcr_mask = (1<<4) | (1<<7) | (1<<8);
+        tpm2_tpml_pcr_selection_from_mask(pcr_mask, TPM2_ALG_SHA256, &pcr_selection);
+        digest_init_sha256(&pcr_values[0], "368f85b3013041dfe203faaa364f00b07c5da7b1e5f1dbf2efb06fa6b9bd92de");
+        digest_init_sha256(&pcr_values[1], "aa1154c9e0a774854ccbed4c8ce7e9b906b3d700a1a8db1772d0341a62dbe51b");
+        digest_init_sha256(&pcr_values[2], "cfde439a2c06af3479ca6bdc60429b90553d65300c5cfcc40004a08c6b5ad81a");
+        assert_se(tpm2_calculate_policy_pcr(&pcr_selection, pcr_values, 3, &d) == 0);
+        assert_se(digest_check(&d, "97e64bcabb64c1fa4b726528644926c8029f5b4458b0575c98c04fe225629a0b"));
+
+        digest_init_sha256(&d, "0000000000000000000000000000000000000000000000000000000000000000");
+        pcr_mask = 0xffff;
+        tpm2_tpml_pcr_selection_from_mask(pcr_mask, TPM2_ALG_SHA256, &pcr_selection);
+        digest_init_sha256(&pcr_values[ 0], "2124793cbbe60c3a8637d3b84a5d054e87c351e1469a285acc04755e8b204dec");
+        digest_init_sha256(&pcr_values[ 1], "bf7592f18adcfdc549fc0b94939f5069a24697f9cff4a0dca29014767b97559d");
+        digest_init_sha256(&pcr_values[ 2], "4b00cff9dee3a364979b2dc241b34568a8ad49fcf2713df259e47dff8875feed");
+        digest_init_sha256(&pcr_values[ 3], "3d458cfe55cc03ea1f443f1562beec8df51c75e14a9fcf9a7234a13f198e7969");
+        digest_init_sha256(&pcr_values[ 4], "368f85b3013041dfe203faaa364f00b07c5da7b1e5f1dbf2efb06fa6b9bd92de");
+        digest_init_sha256(&pcr_values[ 5], "c97c40369691c8e4aa78fb3a52655cd193b780a838b8e23f5f476576919db5e5");
+        digest_init_sha256(&pcr_values[ 6], "3d458cfe55cc03ea1f443f1562beec8df51c75e14a9fcf9a7234a13f198e7969");
+        digest_init_sha256(&pcr_values[ 7], "aa1154c9e0a774854ccbed4c8ce7e9b906b3d700a1a8db1772d0341a62dbe51b");
+        digest_init_sha256(&pcr_values[ 8], "cfde439a2c06af3479ca6bdc60429b90553d65300c5cfcc40004a08c6b5ad81a");
+        digest_init_sha256(&pcr_values[ 9], "9c2bac22ef5ec84fcdb71c3ebf776cba1247e5da980e5ee08e45666a2edf0b8b");
+        digest_init_sha256(&pcr_values[10], "9885873f4d7348199ad286f8f2476d4f866940950f6f9fb9f945ed352dbdcbd2");
+        digest_init_sha256(&pcr_values[11], "42400ab950d21aa79d12cc4fdef67d1087a39ad64900619831c0974dbae54e44");
+        digest_init_sha256(&pcr_values[12], "767d064382e56ca1ad3bdcc6bc596112e6c2008b593d3570d24c2bfa64c4628c");
+        digest_init_sha256(&pcr_values[13], "30c16133175959408c9745d8dafadef5daf4b39cb2be04df0d60089bd46d3cc4");
+        digest_init_sha256(&pcr_values[14], "e3991b7ddd47be7e92726a832d6874c5349b52b789fa0db8b558c69fea29574e");
+        digest_init_sha256(&pcr_values[15], "852dae3ecb992bdeb13d6002fefeeffdd90feca8b378d56681ef2c885d0e5137");
+        assert_se(tpm2_calculate_policy_pcr(&pcr_selection, pcr_values, 16, &d) == 0);
+        assert_se(digest_check(&d, "22be4f1674f792d6345cea9427701068f0e8d9f42755dcc0e927e545a68f9c13"));
+        assert_se(tpm2_calculate_policy_pcr(&pcr_selection, pcr_values, 16, &d) == 0);
+        assert_se(digest_check(&d, "7481fd1b116078eb3ac2456e4ad542c9b46b9b8eb891335771ca8e7c8f8e4415"));
+}
+
 #endif /* HAVE_TPM2 */
 
 DEFINE_TEST_MAIN(LOG_DEBUG);