intel: parse platform-prefixed ME fw_version

Author: q1sh101

include/silicon_parsers.h

@@ -27,6 +27,7 @@ typedef struct {
 
 void bythos_parse_iommu_cmdline(const char *text, bythos_iommu_cmdline_t *cmdline);
 bool bythos_extract_microcode_revision(const char *text, char *buffer, size_t size);
+bool bythos_parse_me_version(const char *text, char *out, size_t size);
 bythos_cpu_vendor_t bythos_cpu_vendor(void);
 /* returns: 1 = all zeros, 0 = non-zero, -1 = not found */
 int bythos_pcr_zero_check(const char *buf, unsigned int pcr_num);

src/check_me_version.c

@@ -35,14 +35,14 @@ size_t bythos_check_me_version(check_result_t *results, size_t max_results) {
         buf[--len] = '\0';
     }
 
-    unsigned int a = 0, b = 0, c = 0, d = 0;
-    if (sscanf(buf, "%u.%u.%u.%u", &a, &b, &c, &d) != 4) {
+    char version[64] = {0};
+    if (!bythos_parse_me_version(buf, version, sizeof(version))) {
         EMIT_SKIP_PARSE("Intel ME version", "ME version");
         return used;
     }
 
     char detail[BYTHOS_DETAIL_MAX];
-    snprintf(detail, sizeof(detail), "%u.%u.%u.%u; compare against Intel SA advisories", a, b, c, d);
+    snprintf(detail, sizeof(detail), "%s; compare against Intel SA advisories", version);
     results[used++] = make_result("Intel ME version", CHECK_OK, detail);
 
     return used;

src/silicon_parsers.c

@@ -210,3 +210,25 @@ bool bythos_extract_microcode_revision(const char *text, char *buffer, size_t si
 
     return false;
 }
+
+bool bythos_parse_me_version(const char *text, char *out, size_t size) {
+    if (text == NULL || out == NULL || size == 0) {
+        return false;
+    }
+
+    unsigned int platform, major, minor, hotfix, build;
+
+    /* mei sysfs fw_version is <platform>:<major>.<minor>.<hotfix>.<build> */
+    if (sscanf(text, "%u:%u.%u.%u.%u", &platform, &major, &minor, &hotfix, &build) == 5) {
+        snprintf(out, size, "%u.%u.%u.%u", major, minor, hotfix, build);
+        return true;
+    }
+
+    /* tolerate a bare version without the platform prefix */
+    if (sscanf(text, "%u.%u.%u.%u", &major, &minor, &hotfix, &build) == 4) {
+        snprintf(out, size, "%u.%u.%u.%u", major, minor, hotfix, build);
+        return true;
+    }
+
+    return false;
+}

tests/silicon_parsers.c

@@ -117,6 +117,19 @@ int main(void) {
         bythos_parse_memory_encryption_flags("flags : sme\n", NULL);
     }
 
+    {
+        char me_ver[64] = {0};
+        assert_true("me_version_colon_form",
+            bythos_parse_me_version("0:21.2.21.2081", me_ver, sizeof(me_ver)));
+        assert_true("me_version_strips_platform", strcmp(me_ver, "21.2.21.2081") == 0);
+        assert_true("me_version_dot_form",
+            bythos_parse_me_version("21.2.21.2081", me_ver, sizeof(me_ver)));
+        assert_false("me_version_garbage",
+            bythos_parse_me_version("not-a-version", me_ver, sizeof(me_ver)));
+        assert_false("me_version_null",
+            bythos_parse_me_version(NULL, me_ver, sizeof(me_ver)));
+    }
+
     printf("silicon parsers ok\n");
     return 0;
 }