tpm2-util: rename tpm2_extend_bytes()→tpm2_pcr_extend_bytes() and make it take struct iovec

We soon want to add the ability to extend into nvindexes in addition to
PCRs, hence rename the function to make clear it is about pcr extension.

While we are at it, switch things over to "struct iovec" as we generally
try to do it now in tpm2-util.[ch] these days.

src/cryptsetup/cryptsetup.c

@@ -1047,7 +1047,7 @@ static int measure_volume_key(
         if (!s)
                 return log_oom();
 
-        r = tpm2_extend_bytes(c, l ?: arg_tpm2_measure_banks, arg_tpm2_measure_pcr, s, SIZE_MAX, volume_key, volume_key_size, TPM2_EVENT_VOLUME_KEY, s);
+        r = tpm2_pcr_extend_bytes(c, l ?: arg_tpm2_measure_banks, arg_tpm2_measure_pcr, &IOVEC_MAKE_STRING(s), &IOVEC_MAKE(volume_key, volume_key_size), TPM2_EVENT_VOLUME_KEY, s);
         if (r < 0)
                 return log_error_errno(r, "Could not extend PCR: %m");
 

src/pcrextend/pcrextend.c

@@ -233,7 +233,7 @@ static int extend_now(unsigned pcr, const void *data, size_t size, Tpm2Userspace
 
         log_debug("Measuring '%s' into PCR index %u, banks %s.", safe, pcr, joined_banks);
 
-        r = tpm2_extend_bytes(c, arg_banks, pcr, data, size, /* secret= */ NULL, /* secret_size= */ 0, event, safe);
+        r = tpm2_pcr_extend_bytes(c, arg_banks, pcr, &IOVEC_MAKE(data, size), /* secret= */ NULL, event, safe);
         if (r < 0)
                 return log_error_errno(r, "Could not extend PCR: %m");
 

src/shared/tpm2-util.c

@@ -6321,14 +6321,12 @@ static int tpm2_userspace_log(
 }
 #endif
 
-int tpm2_extend_bytes(
+int tpm2_pcr_extend_bytes(
                 Tpm2Context *c,
                 char **banks,
                 unsigned pcr_index,
-                const void *data,
-                size_t data_size,
-                const void *secret,
-                size_t secret_size,
+                const struct iovec *data,
+                const struct iovec *secret,
                 Tpm2UserspaceEventType event_type,
                 const char *description) {
 
@@ -6338,17 +6336,15 @@ int tpm2_extend_bytes(
         TSS2_RC rc;
 
         assert(c);
-        assert(data || data_size == 0);
-        assert(secret || secret_size == 0);
-
-        if (data_size == SIZE_MAX)
-                data_size = strlen(data);
-        if (secret_size == SIZE_MAX)
-                secret_size = strlen(secret);
+        assert(iovec_is_valid(data));
+        assert(iovec_is_valid(secret));
 
         if (pcr_index >= TPM2_PCRS_MAX)
                 return log_debug_errno(SYNTHETIC_ERRNO(EOPNOTSUPP), "Can't measure into unsupported PCR %u, refusing.", pcr_index);
 
+        if (!iovec_is_set(data))
+                data = &iovec_empty;
+
         if (strv_isempty(banks))
                 return 0;
 
@@ -6376,10 +6372,10 @@ int tpm2_extend_bytes(
                  * secret for other purposes, maybe because it needs a shorter secret derived from it for
                  * some unrelated purpose, who knows). Hence we instead measure an HMAC signature of a
                  * private non-secret string instead. */
-                if (secret_size > 0) {
-                        if (!HMAC(implementation, secret, secret_size, data, data_size, (unsigned char*) &values.digests[values.count].digest, NULL))
+                if (iovec_is_set(secret) > 0) {
+                        if (!HMAC(implementation, secret->iov_base, secret->iov_len, data->iov_base, data->iov_len, (unsigned char*) &values.digests[values.count].digest, NULL))
                                 return log_debug_errno(SYNTHETIC_ERRNO(ENOTRECOVERABLE), "Failed to calculate HMAC of data to measure.");
-                } else if (EVP_Digest(data, data_size, (unsigned char*) &values.digests[values.count].digest, NULL, implementation, NULL) != 1)
+                } else if (EVP_Digest(data->iov_base, data->iov_len, (unsigned char*) &values.digests[values.count].digest, NULL, implementation, NULL) != 1)
                         return log_debug_errno(SYNTHETIC_ERRNO(ENOTRECOVERABLE), "Failed to hash data to measure.");
 
                 values.count++;

src/shared/tpm2-util.h

@@ -149,7 +149,7 @@ typedef enum Tpm2UserspaceEventType {
 const char* tpm2_userspace_event_type_to_string(Tpm2UserspaceEventType type) _const_;
 Tpm2UserspaceEventType tpm2_userspace_event_type_from_string(const char *s) _pure_;
 
-int tpm2_extend_bytes(Tpm2Context *c, char **banks, unsigned pcr_index, const void *data, size_t data_size, const void *secret, size_t secret_size, Tpm2UserspaceEventType event, const char *description);
+int tpm2_pcr_extend_bytes(Tpm2Context *c, char **banks, unsigned pcr_index, const struct iovec *data, const struct iovec *secret, Tpm2UserspaceEventType event, const char *description);
 
 uint32_t tpm2_tpms_pcr_selection_to_mask(const TPMS_PCR_SELECTION *s);
 void tpm2_tpms_pcr_selection_from_mask(uint32_t mask, TPMI_ALG_HASH hash, TPMS_PCR_SELECTION *ret);