tpm2-util: add tpm2_get_vendor_info() helper for getting TPM2 vendor info from the device

src/shared/tpm2-util.c

@@ -43,6 +43,7 @@
 #include "time-util.h"
 #include "tpm2-pcr.h"
 #include "tpm2-util.h"
+#include "unaligned.h"
 #include "virt.h"
 
 #if HAVE_OPENSSL
@@ -348,6 +349,114 @@ static int tpm2_get_capability(
         return more == TPM2_YES;
 }
 
+static char *mangle_vendor_chars(char *c, size_t n) {
+        char *end = c;
+        assert(c || n == 0);
+
+        /* Suppress all control characters, whitespace and non-ASCII bytes */
+        for (char *x = c; x < c + n; x++) {
+                if (!IN_SET(*x, ' ', 0))
+                        end = x + 1;
+
+                if ((unsigned char) *x <= (unsigned char) ' ' ||
+                    (unsigned char) *x >= 127)
+                        *x = '_';
+        }
+
+        /* Drop trailing spaces and NUL bytes */
+        *end = 0;
+        return c;
+}
+
+int tpm2_get_vendor_info(
+                Tpm2Context *c,
+                Tpm2VendorInfo *ret) {
+
+        int r;
+
+        assert(c);
+        assert(ret);
+
+        TPMU_CAPABILITIES capabilities = {};
+        r = tpm2_get_capability(
+                        c,
+                        TPM2_CAP_TPM_PROPERTIES,
+                        TPM2_PT_FAMILY_INDICATOR,
+                        TPM2_PT_FIRMWARE_VERSION_2 - TPM2_PT_FAMILY_INDICATOR + 1, /* get all relevant fields at once */
+                        &capabilities);
+        if (r < 0)
+                return r;
+
+        Tpm2VendorInfo info = {};
+
+        for (uint32_t i = 0; i < capabilities.tpmProperties.count; i++) {
+                TPMS_TAGGED_PROPERTY *p = capabilities.tpmProperties.tpmProperty + i;
+
+                switch (p->property) {
+
+                case TPM2_PT_FAMILY_INDICATOR:
+                        unaligned_write_be32(info.family_indicator, p->value);
+                        mangle_vendor_chars(info.family_indicator, sizeof(info.family_indicator));
+                        break;
+
+                case TPM2_PT_LEVEL:
+                        info.level = p->value;
+                        break;
+
+                case TPM2_PT_REVISION:
+                        info.revision_major = p->value / 100;
+                        info.revision_minor = p->value % 100;
+                        break;
+
+                case TPM2_PT_DAY_OF_YEAR:
+                        info.day_of_year = p->value;
+                        break;
+
+                case TPM2_PT_YEAR:
+                        info.year = p->value;
+                        break;
+
+                case TPM2_PT_MANUFACTURER:
+                        unaligned_write_be32(info.manufacturer, p->value);
+                        mangle_vendor_chars(info.manufacturer, sizeof(info.manufacturer));
+                        break;
+
+                case TPM2_PT_VENDOR_STRING_1:
+                        unaligned_write_be32(info.vendor_string+0, p->value);
+                        break;
+
+                case TPM2_PT_VENDOR_STRING_2:
+                        unaligned_write_be32(info.vendor_string+4, p->value);
+                        break;
+
+                case TPM2_PT_VENDOR_STRING_3:
+                        unaligned_write_be32(info.vendor_string+8, p->value);
+                        break;
+
+                case TPM2_PT_VENDOR_STRING_4:
+                        unaligned_write_be32(info.vendor_string+12, p->value);
+                        break;
+
+                case TPM2_PT_VENDOR_TPM_TYPE:
+                        info.vendor_tpm_type = p->value;
+                        break;
+
+                case TPM2_PT_FIRMWARE_VERSION_1:
+                        info.firmware_version_major = p->value >> 16;
+                        info.firmware_version_minor = p->value & 0xFFFFU;
+                        break;
+
+                case TPM2_PT_FIRMWARE_VERSION_2:
+                        info.firmware_version2 = p->value;
+                        break;
+                }
+        }
+
+        mangle_vendor_chars(info.vendor_string, sizeof(info.vendor_string));
+        *ret = TAKE_STRUCT(info);
+        return 0;
+}
+
 #define TPMA_CC_TO_TPM2_CC(cca) (((cca) & TPMA_CC_COMMANDINDEX_MASK) >> TPMA_CC_COMMANDINDEX_SHIFT)
 
 static int tpm2_cache_capabilities(Tpm2Context *c) {

src/shared/tpm2-util.h

@@ -195,6 +195,23 @@ static inline int tpm2_digest_init(TPMI_ALG_HASH alg, TPM2B_DIGEST *digest) {
         return tpm2_digest_many(alg, digest, NULL, 0, false);
 }
 
+typedef struct Tpm2VendorInfo {
+        uint32_t level;
+        uint32_t revision_major;
+        uint32_t revision_minor;
+        uint32_t day_of_year;
+        uint32_t year;
+        uint32_t vendor_tpm_type;
+        uint16_t firmware_version_major;
+        uint16_t firmware_version_minor;
+        uint32_t firmware_version2;
+        char family_indicator[4+1];
+        char manufacturer[4+1];
+        char vendor_string[4*4+1];
+} Tpm2VendorInfo;
+
+int tpm2_get_vendor_info(Tpm2Context *c, Tpm2VendorInfo *ret);
+
 void tpm2_log_debug_tpml_pcr_selection(const TPML_PCR_SELECTION *l, const char *msg);
 void tpm2_log_debug_pcr_value(const Tpm2PCRValue *pcr_value, const char *msg);
 void tpm2_log_debug_buffer(const void *buffer, size_t size, const char *msg);