measure: honour phases when signing
This commit is contained in:
Lennart Poettering
+157
-135
@@ -779,6 +779,10 @@ static int verb_sign(int argc, char *argv[], void *userdata) {
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if (r < 0)
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return r;
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r = pcr_states_save(pcr_states, n);
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if (r < 0)
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return r;
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r = dlopen_tpm2();
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if (r < 0)
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return r;
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@@ -787,147 +791,165 @@ static int verb_sign(int argc, char *argv[], void *userdata) {
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if (r < 0)
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return r;
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for (size_t i = 0; i < n; i++) {
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static const TPMT_SYM_DEF symmetric = {
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.algorithm = TPM2_ALG_AES,
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.keyBits.aes = 128,
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.mode.aes = TPM2_ALG_CFB,
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};
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PcrState *p = pcr_states + i;
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STRV_FOREACH(phase, arg_phase) {
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rc = sym_Esys_StartAuthSession(
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c.esys_context,
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ESYS_TR_NONE,
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ESYS_TR_NONE,
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ESYS_TR_NONE,
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ESYS_TR_NONE,
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ESYS_TR_NONE,
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NULL,
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TPM2_SE_TRIAL,
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&symmetric,
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TPM2_ALG_SHA256,
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&session_handle);
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if (rc != TSS2_RC_SUCCESS) {
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r = log_error_errno(SYNTHETIC_ERRNO(ENOTRECOVERABLE),
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"Failed to open session in TPM: %s", sym_Tss2_RC_Decode(rc));
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goto finish;
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}
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/* Generate a single hash value from the PCRs included in our policy. Given that that's
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* exactly one, the calculation is trivial. */
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TPM2B_DIGEST intermediate_digest = {
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.size = SHA256_DIGEST_SIZE,
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};
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assert(sizeof(intermediate_digest.buffer) >= SHA256_DIGEST_SIZE);
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sha256_direct(p->value, p->value_size, intermediate_digest.buffer);
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int tpmalg = tpm2_pcr_bank_from_string(EVP_MD_name(p->md));
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if (tpmalg < 0) {
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log_error_errno(tpmalg, "Unsupported PCR bank");
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goto finish;
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}
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TPML_PCR_SELECTION pcr_selection;
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tpm2_pcr_mask_to_selection(1 << TPM_PCR_INDEX_KERNEL_IMAGE, tpmalg, &pcr_selection);
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rc = sym_Esys_PolicyPCR(
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c.esys_context,
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session_handle,
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ESYS_TR_NONE,
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ESYS_TR_NONE,
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ESYS_TR_NONE,
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&intermediate_digest,
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&pcr_selection);
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if (rc != TSS2_RC_SUCCESS) {
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r = log_error_errno(SYNTHETIC_ERRNO(ENOTRECOVERABLE),
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"Failed to push PCR policy into TPM: %s", sym_Tss2_RC_Decode(rc));
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goto finish;
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}
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_cleanup_(Esys_Freep) TPM2B_DIGEST *pcr_policy_digest = NULL;
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rc = sym_Esys_PolicyGetDigest(
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c.esys_context,
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session_handle,
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ESYS_TR_NONE,
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ESYS_TR_NONE,
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ESYS_TR_NONE,
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&pcr_policy_digest);
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if (rc != TSS2_RC_SUCCESS) {
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r = log_error_errno(SYNTHETIC_ERRNO(ENOTRECOVERABLE),
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"Failed to get policy digest from TPM: %s", sym_Tss2_RC_Decode(rc));
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goto finish;
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}
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session_handle = tpm2_flush_context_verbose(c.esys_context, session_handle);
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_cleanup_(EVP_MD_CTX_freep) EVP_MD_CTX* mdctx = NULL;
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mdctx = EVP_MD_CTX_new();
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if (!mdctx) {
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r = log_oom();
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goto finish;
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}
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if (EVP_DigestSignInit(mdctx, NULL, p->md, NULL, privkey) != 1) {
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r = log_error_errno(SYNTHETIC_ERRNO(ENOTRECOVERABLE),
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"Failed to initialize signature context.");
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goto finish;
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}
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if (EVP_DigestSignUpdate(mdctx, pcr_policy_digest->buffer, pcr_policy_digest->size) != 1) {
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r = log_error_errno(SYNTHETIC_ERRNO(ENOTRECOVERABLE),
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"Failed to sign data.");
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goto finish;
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}
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size_t ss;
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if (EVP_DigestSignFinal(mdctx, NULL, &ss) != 1) {
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r = log_error_errno(SYNTHETIC_ERRNO(ENOTRECOVERABLE),
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"Failed to finalize signature");
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goto finish;
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}
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_cleanup_free_ void *sig = malloc(ss);
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if (!ss) {
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r = log_oom();
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goto finish;
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}
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if (EVP_DigestSignFinal(mdctx, sig, &ss) != 1) {
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r = log_error_errno(SYNTHETIC_ERRNO(ENOTRECOVERABLE),
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"Failed to acquire signature data");
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goto finish;
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}
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_cleanup_free_ void *pubkey_fp = NULL;
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size_t pubkey_fp_size = 0;
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r = pubkey_fingerprint(pubkey, EVP_sha256(), &pubkey_fp, &pubkey_fp_size);
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r = measure_phase(pcr_states, n, *phase);
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if (r < 0)
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goto finish;
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return r;
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_cleanup_(json_variant_unrefp) JsonVariant *bv = NULL, *a = NULL;
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for (size_t i = 0; i < n; i++) {
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static const TPMT_SYM_DEF symmetric = {
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.algorithm = TPM2_ALG_AES,
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.keyBits.aes = 128,
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.mode.aes = TPM2_ALG_CFB,
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};
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PcrState *p = pcr_states + i;
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r = tpm2_make_pcr_json_array(UINT64_C(1) << TPM_PCR_INDEX_KERNEL_IMAGE, &a);
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if (r < 0) {
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log_error_errno(r, "Failed to build JSON PCR mask array: %m");
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goto finish;
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rc = sym_Esys_StartAuthSession(
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c.esys_context,
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ESYS_TR_NONE,
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ESYS_TR_NONE,
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ESYS_TR_NONE,
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ESYS_TR_NONE,
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ESYS_TR_NONE,
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NULL,
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TPM2_SE_TRIAL,
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&symmetric,
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TPM2_ALG_SHA256,
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&session_handle);
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if (rc != TSS2_RC_SUCCESS) {
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r = log_error_errno(SYNTHETIC_ERRNO(ENOTRECOVERABLE),
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"Failed to open session in TPM: %s", sym_Tss2_RC_Decode(rc));
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goto finish;
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}
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/* Generate a single hash value from the PCRs included in our policy. Given that that's
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* exactly one, the calculation is trivial. */
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TPM2B_DIGEST intermediate_digest = {
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.size = SHA256_DIGEST_SIZE,
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};
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assert(sizeof(intermediate_digest.buffer) >= SHA256_DIGEST_SIZE);
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sha256_direct(p->value, p->value_size, intermediate_digest.buffer);
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int tpmalg = tpm2_pcr_bank_from_string(EVP_MD_name(p->md));
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if (tpmalg < 0) {
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log_error_errno(tpmalg, "Unsupported PCR bank");
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goto finish;
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}
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TPML_PCR_SELECTION pcr_selection;
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tpm2_pcr_mask_to_selection(1 << TPM_PCR_INDEX_KERNEL_IMAGE, tpmalg, &pcr_selection);
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rc = sym_Esys_PolicyPCR(
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c.esys_context,
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session_handle,
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ESYS_TR_NONE,
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ESYS_TR_NONE,
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ESYS_TR_NONE,
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&intermediate_digest,
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&pcr_selection);
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if (rc != TSS2_RC_SUCCESS) {
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r = log_error_errno(SYNTHETIC_ERRNO(ENOTRECOVERABLE),
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"Failed to push PCR policy into TPM: %s", sym_Tss2_RC_Decode(rc));
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goto finish;
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}
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_cleanup_(Esys_Freep) TPM2B_DIGEST *pcr_policy_digest = NULL;
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rc = sym_Esys_PolicyGetDigest(
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c.esys_context,
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session_handle,
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ESYS_TR_NONE,
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ESYS_TR_NONE,
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ESYS_TR_NONE,
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&pcr_policy_digest);
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if (rc != TSS2_RC_SUCCESS) {
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r = log_error_errno(SYNTHETIC_ERRNO(ENOTRECOVERABLE),
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"Failed to get policy digest from TPM: %s", sym_Tss2_RC_Decode(rc));
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goto finish;
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}
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session_handle = tpm2_flush_context_verbose(c.esys_context, session_handle);
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_cleanup_(EVP_MD_CTX_freep) EVP_MD_CTX* mdctx = NULL;
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mdctx = EVP_MD_CTX_new();
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if (!mdctx) {
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r = log_oom();
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goto finish;
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}
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if (EVP_DigestSignInit(mdctx, NULL, p->md, NULL, privkey) != 1) {
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r = log_error_errno(SYNTHETIC_ERRNO(ENOTRECOVERABLE),
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"Failed to initialize signature context.");
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goto finish;
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}
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if (EVP_DigestSignUpdate(mdctx, pcr_policy_digest->buffer, pcr_policy_digest->size) != 1) {
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r = log_error_errno(SYNTHETIC_ERRNO(ENOTRECOVERABLE),
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"Failed to sign data.");
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goto finish;
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}
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size_t ss;
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if (EVP_DigestSignFinal(mdctx, NULL, &ss) != 1) {
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r = log_error_errno(SYNTHETIC_ERRNO(ENOTRECOVERABLE),
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"Failed to finalize signature");
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goto finish;
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}
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_cleanup_free_ void *sig = malloc(ss);
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if (!ss) {
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r = log_oom();
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goto finish;
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}
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if (EVP_DigestSignFinal(mdctx, sig, &ss) != 1) {
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r = log_error_errno(SYNTHETIC_ERRNO(ENOTRECOVERABLE),
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"Failed to acquire signature data");
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goto finish;
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}
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_cleanup_free_ void *pubkey_fp = NULL;
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size_t pubkey_fp_size = 0;
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r = pubkey_fingerprint(pubkey, EVP_sha256(), &pubkey_fp, &pubkey_fp_size);
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if (r < 0)
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goto finish;
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_cleanup_(json_variant_unrefp) JsonVariant *a = NULL;
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r = tpm2_make_pcr_json_array(UINT64_C(1) << TPM_PCR_INDEX_KERNEL_IMAGE, &a);
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if (r < 0) {
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log_error_errno(r, "Failed to build JSON PCR mask array: %m");
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goto finish;
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}
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_cleanup_(json_variant_unrefp) JsonVariant *bv = NULL;
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r = json_build(&bv, JSON_BUILD_OBJECT(
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JSON_BUILD_PAIR("pcrs", JSON_BUILD_VARIANT(a)), /* PCR mask */
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JSON_BUILD_PAIR("pkfp", JSON_BUILD_HEX(pubkey_fp, pubkey_fp_size)), /* SHA256 fingerprint of public key (DER) used for the signature */
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JSON_BUILD_PAIR("pol", JSON_BUILD_HEX(pcr_policy_digest->buffer, pcr_policy_digest->size)), /* TPM2 policy hash that is signed */
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JSON_BUILD_PAIR("sig", JSON_BUILD_BASE64(sig, ss)))); /* signature data */
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if (r < 0) {
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log_error_errno(r, "Failed to build JSON object: %m");
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goto finish;
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}
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_cleanup_(json_variant_unrefp) JsonVariant *av = NULL;
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av = json_variant_ref(json_variant_by_key(v, p->bank));
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r = json_variant_append_array(&av, bv);
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if (r < 0) {
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log_error_errno(r, "Failed to append JSON object: %m");
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goto finish;
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}
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r = json_variant_set_field(&v, p->bank, av);
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if (r < 0) {
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log_error_errno(r, "Failed to add JSON field: %m");
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goto finish;
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}
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}
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r = json_build(&bv, JSON_BUILD_ARRAY(
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JSON_BUILD_OBJECT(
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JSON_BUILD_PAIR("pcrs", JSON_BUILD_VARIANT(a)), /* PCR mask */
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JSON_BUILD_PAIR("pkfp", JSON_BUILD_HEX(pubkey_fp, pubkey_fp_size)), /* SHA256 fingerprint of public key (DER) used for the signature */
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JSON_BUILD_PAIR("pol", JSON_BUILD_HEX(pcr_policy_digest->buffer, pcr_policy_digest->size)), /* TPM2 policy hash that is signed */
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JSON_BUILD_PAIR("sig", JSON_BUILD_BASE64(sig, ss))))); /* signature data */
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if (r < 0) {
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log_error_errno(r, "Failed to build JSON object: %m");
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goto finish;
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}
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r = json_variant_set_field(&v, p->bank, bv);
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if (r < 0) {
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log_error_errno(r, "Failed to add JSON field: %m");
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goto finish;
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}
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/* Return to the original kernel measurement for the next phase calculation */
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pcr_states_restore(pcr_states, n);
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}
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if (arg_json_format_flags & (JSON_FORMAT_PRETTY|JSON_FORMAT_PRETTY_AUTO))
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