Fenrir Fix: Extended key usage printed by masking a bitmap with OID-sum constants

src/x509/clu_cert_setup.c

@@ -670,7 +670,10 @@ int wolfCLU_certSetup(int argc, char **argv)
             keyUsage = 0;
         }
 
-        wolfCLU_extKeyUsagePrint(out, keyUsage, 0, 1);
+        if ((ret = wolfCLU_extKeyUsagePrint(out, keyUsage, 0, 1))
+                != WOLFCLU_SUCCESS) {
+            wolfCLU_LogError("Unable to print ext key usage");
+        }
 #else
         wolfCLU_LogError("Extended key function not supported by this"
                          " version of wolfSSL");

src/x509/clu_parse.c

@@ -143,67 +143,67 @@ int wolfCLU_printX509PubKey(WOLFSSL_X509* x509, WOLFSSL_BIO* out)
 }
 
 
+/* Print the extended key usages held in 'keyUsage'.
+ *
+ * 'keyUsage' is the bit map returned by wolfSSL_X509_get_extended_key_usage(),
+ * so it must be masked with the XKU_* flags rather than with the
+ * ExtKeyUsage_Sum OID values, which are not single bit flags.
+ *
+ * When 'flag' is set every purpose is listed with a YES/NO verdict, otherwise
+ * only the purposes present in the certificate are printed.
+ */
 int wolfCLU_extKeyUsagePrint(WOLFSSL_BIO* bio, unsigned int keyUsage,
         int indent, int flag)
 {
-    unsigned int ava;
+#if LIBWOLFSSL_VERSION_HEX > 0x05001000
+    unsigned int i;
     char scratch[MAX_TERM_WIDTH];
 
-    if (flag) {
-        XSNPRINTF(scratch, MAX_TERM_WIDTH, "%*s%s\n", indent, "",
-                "Certificate Purpose:");
-        wolfSSL_BIO_write(bio, scratch, (int)XSTRLEN(scratch));
-    }
-
-    ava = (EKU_ANY_OID & keyUsage);
-    if (ava | flag) {
-        XSNPRINTF(scratch, MAX_TERM_WIDTH, "%*s%s%s\n", indent, "",
-                "Any Extended Key Usage",
-                (flag == 1)? (ava > 0) ? " : YES" : " : NO" : "");
-        wolfSSL_BIO_write(bio, scratch, (int)XSTRLEN(scratch));
-    }
+    static const struct {
+        unsigned int bit;
+        const char* name;
+    } extKeyUsages[] = {
+        { XKU_ANYEKU, "Any Extended Key Usage" },
+        { XKU_SSL_SERVER, "TLS Web Server Authentication" },
+        { XKU_SSL_CLIENT, "TLS Web Client Authentication" },
+        { XKU_CODE_SIGN, "Code Signing" },
+        { XKU_OCSP_SIGN, "OCSP Signing" },
+        { XKU_SMIME, "Email Protect" },
+        { XKU_TIMESTAMP, "Time Stamp Signing" },
+    };
 
-    ava = (EKU_SERVER_AUTH_OID & keyUsage);
-    if (ava | flag) {
-        XSNPRINTF(scratch, MAX_TERM_WIDTH, "%*s%s%s\n", indent, "",
-                "TLS Web Server Authentication",
-                (flag == 1)? (ava > 0) ? " : YES" : " : NO" : "");
-        wolfSSL_BIO_write(bio, scratch, (int)XSTRLEN(scratch));
-    }
-
-    ava = (EKU_CLIENT_AUTH_OID & keyUsage);
-    if (ava | flag) {
-        XSNPRINTF(scratch, MAX_TERM_WIDTH, "%*s%s%s\n", indent, "",
-                "TLS Web Client Authentication",
-                (flag == 1)? (ava > 0) ? " : YES" : " : NO" : "");
-        wolfSSL_BIO_write(bio, scratch, (int)XSTRLEN(scratch));
+    if (bio == NULL) {
+        return WOLFCLU_FATAL_ERROR;
     }
 
-    ava = (EKU_OCSP_SIGN_OID & keyUsage);
-    if (ava | flag) {
-        XSNPRINTF(scratch, MAX_TERM_WIDTH, "%*s%s%s\n", indent, "",
-                "OCSP Signing",
-                (flag == 1)? (ava > 0) ? " : YES" : " : NO" : "");
+    if (flag) {
+        XSNPRINTF(scratch, MAX_TERM_WIDTH, "%*s%s\n", indent, "",
+                "Certificate Purpose:");
         wolfSSL_BIO_write(bio, scratch, (int)XSTRLEN(scratch));
     }
 
-    ava = (EKU_EMAILPROTECT_OID & keyUsage);
-    if (ava | flag) {
-        XSNPRINTF(scratch, MAX_TERM_WIDTH, "%*s%s%s\n", indent, "",
-                "Email Protect",
-                (flag == 1)? (ava > 0) ? " : YES" : " : NO" : "");
-        wolfSSL_BIO_write(bio, scratch, (int)XSTRLEN(scratch));
-    }
+    for (i = 0; i < (sizeof(extKeyUsages) / sizeof(extKeyUsages[0])); i++) {
+        unsigned int ava = (extKeyUsages[i].bit & keyUsage);
 
-    ava = (EKU_TIMESTAMP_OID & keyUsage);
-    if (ava | flag) {
-        XSNPRINTF(scratch, MAX_TERM_WIDTH, "%*s%s%s\n", indent, "",
-                "Time Stamp Signing",
-                (flag == 1)? (ava > 0) ? " : YES" : " : NO" : "");
-        wolfSSL_BIO_write(bio, scratch, (int)XSTRLEN(scratch));
+        if (ava || flag) {
+            XSNPRINTF(scratch, MAX_TERM_WIDTH, "%*s%s%s\n", indent, "",
+                    extKeyUsages[i].name,
+                    (flag == 1)? (ava > 0) ? " : YES" : " : NO" : "");
+            wolfSSL_BIO_write(bio, scratch, (int)XSTRLEN(scratch));
+        }
     }
 
-    return WOLFSSL_SUCCESS;
+    return WOLFCLU_SUCCESS;
+#else
+    (void)bio;
+    (void)keyUsage;
+    (void)indent;
+    (void)flag;
+
+    wolfCLU_LogError("Extended key function not supported by this"
+                     " version of wolfSSL");
+    return NOT_COMPILED_IN;
+#endif
 }
 
 #endif /* WOLFCLU_NO_FILESYSTEM */

tests/x509/expect-purpose.txt

@@ -1,7 +1,8 @@
 Certificate Purpose:
-Any Extended Key Usage : YES
+Any Extended Key Usage : NO
 TLS Web Server Authentication : YES
 TLS Web Client Authentication : YES
-OCSP Signing : YES
-Email Protect : YES
-Time Stamp Signing : YES
+Code Signing : NO
+OCSP Signing : NO
+Email Protect : NO
+Time Stamp Signing : NO

tests/x509/x509-process-test.py

@@ -420,6 +420,81 @@ def test_3j_purpose(self):
         self.assertEqual(r.returncode, 0, r.stderr)
         self.assertEqual(r.stdout.strip(), expected)
 
+    def test_3j2_purpose_per_cert(self):
+        """-purpose must report exactly the EKUs each certificate carries.
+
+        The purposes are read from a bit map, so a cert with a single EKU has
+        to answer NO to every other purpose. Covers the regression where the
+        bit map was masked with OID sums instead of the XKU_* flags, which
+        made every purpose read YES (or every one NO) regardless of the cert.
+        """
+        # cert -> the purposes that must report YES; all others must be NO
+        cases = {
+            "server-cert.pem": ["TLS Web Server Authentication",
+                                "TLS Web Client Authentication"],
+            "server-ecc.pem": ["TLS Web Server Authentication"],
+            "client-int-cert.pem": ["TLS Web Client Authentication",
+                                    "Email Protect"],
+            "ocsp-responder-cert.pem": ["OCSP Signing"],
+        }
+        for cert, expected_yes in cases.items():
+            with self.subTest(cert=cert):
+                r = run_wolfssl("x509", "-in", os.path.join(CERTS_DIR, cert),
+                                "-purpose", "-noout")
+                self.assertEqual(r.returncode, 0, r.stderr)
+
+                lines = r.stdout.strip().splitlines()
+                self.assertEqual(lines[0].strip(), "Certificate Purpose:")
+
+                got_yes = []
+                for line in lines[1:]:
+                    name, _, verdict = line.rpartition(" : ")
+                    self.assertIn(verdict, ("YES", "NO"),
+                                  "bad purpose line: {}".format(line))
+                    if verdict == "YES":
+                        got_yes.append(name.strip())
+
+                self.assertEqual(sorted(got_yes), sorted(expected_yes))
+
+    @unittest.skipUnless(HAS_OPENSSL, "openssl is not avaliable")
+    def test_3j3_purpose_generated_ekus(self):
+        """-purpose on EKUs no checked-in certificate carries.
+
+        codeSigning, timeStamping and anyExtendedKeyUsage are absent from
+        certs/, so build a cert with them to cover the rest of the bit map.
+        """
+        key = "test_3j3.key"
+        cert = "test_3j3.pem"
+        conf = "test_3j3.cnf"
+        self._clean(key, cert, conf)
+
+        with open(conf, "w") as f:
+            f.write("[req]\n"
+                    "distinguished_name = dn\n"
+                    "x509_extensions = v3\n"
+                    "prompt = no\n"
+                    "[dn]\n"
+                    "CN = wolfCLU EKU test\n"
+                    "[v3]\n"
+                    "extendedKeyUsage = codeSigning, timeStamping, "
+                    "anyExtendedKeyUsage\n")
+        # TODO: change this to wolfssl when
+        # https://github.com/wolfSSL/wolfCLU/pull/285 is merged
+        subprocess.run(
+            ["openssl", "req", "-x509", "-newkey", "rsa:2048", "-nodes",
+             "-keyout", key, "-out", cert, "-days", "1", "-config", conf],
+            check=True, capture_output=True, timeout=120)
+
+        r = run_wolfssl("x509", "-in", cert, "-purpose", "-noout")
+        self.assertEqual(r.returncode, 0, r.stderr)
+
+        got_yes = [line.rpartition(" : ")[0].strip()
+                   for line in r.stdout.strip().splitlines()[1:]
+                   if line.rstrip().endswith("YES")]
+        self.assertEqual(sorted(got_yes),
+                         sorted(["Any Extended Key Usage", "Code Signing",
+                                 "Time Stamp Signing"]))
+
     def test_3k_hash(self):
         expected_file = os.path.join(TESTS_X509_DIR, "expect-hash.txt")
         with open(expected_file) as f: