pcrextend: automatically measure SMBIOS product ID at boot

Now that PCRs are not that expensive anymore, let's use them to measure
the SMBIOS product ID to one.

src/shared/pcrextend-util.c

@@ -10,6 +10,7 @@
 #include "errno-util.h"
 #include "escape.h"
 #include "fd-util.h"
+#include "id128-util.h"
 #include "log.h"
 #include "mountpoint-util.h"
 #include "pcrextend-util.h"
@@ -158,3 +159,24 @@ int pcrextend_machine_id_word(char **ret) {
         *ret = TAKE_PTR(word);
         return 0;
 }
+
+int pcrextend_product_id_word(char **ret) {
+        _cleanup_free_ char *word = NULL;
+        sd_id128_t pid;
+        int r;
+
+        assert(ret);
+
+        r = id128_get_product(&pid);
+        if (IN_SET(r, -ENOENT, -EADDRNOTAVAIL)) /* No product UUID field, or an all-zero or all-0xFF UUID */
+                word = strdup("product-id:missing");
+        else if (r < 0)
+                return log_error_errno(r, "Failed to acquire product ID: %m");
+        else
+                word = strjoin("product-id:", SD_ID128_TO_STRING(pid));
+        if (!word)
+                return log_oom();
+
+        *ret = TAKE_PTR(word);
+        return 0;
+}

src/shared/pcrextend-util.h

@@ -3,3 +3,4 @@
 
 int pcrextend_file_system_word(const char *path, char **ret, char **ret_normalized_path);
 int pcrextend_machine_id_word(char **ret);
+int pcrextend_product_id_word(char **ret);

src/shared/tpm2-util.c

@@ -6424,6 +6424,7 @@ static const char* tpm2_userspace_event_type_table[_TPM2_USERSPACE_EVENT_TYPE_MA
         [TPM2_EVENT_FILESYSTEM] = "filesystem",
         [TPM2_EVENT_VOLUME_KEY] = "volume-key",
         [TPM2_EVENT_MACHINE_ID] = "machine-id",
+        [TPM2_EVENT_PRODUCT_ID] = "product-id",
 };
 
 DEFINE_STRING_TABLE_LOOKUP(tpm2_userspace_event_type, Tpm2UserspaceEventType);

src/shared/tpm2-util.h

@@ -142,6 +142,7 @@ typedef enum Tpm2UserspaceEventType {
         TPM2_EVENT_FILESYSTEM,
         TPM2_EVENT_VOLUME_KEY,
         TPM2_EVENT_MACHINE_ID,
+        TPM2_EVENT_PRODUCT_ID,
         _TPM2_USERSPACE_EVENT_TYPE_MAX,
         _TPM2_USERSPACE_EVENT_TYPE_INVALID = -EINVAL,
 } Tpm2UserspaceEventType;