X509 time: tighten validation per RFC 5280

- Reject fractional seconds
- Reject offsets
- Check that the date/time digits are in valid range.
- Add documentation for X509_cmp_time

GH issue 2620

Backported from 80770da39e

Reviewed-by: Rich Salz <rsalz@openssl.org>
Reviewed-by: Matthias St. Pierre <Matthias.St.Pierre@ncp-e.com>
(Merged from https://github.com/openssl/openssl/pull/6181)

3 files changed, 229 insertions, 1 deletions

diff --git a/test/build.info b/test/build.info
index 1c11ae1350..dcb398517c 100644
--- a/test/build.info
+++ b/test/build.info
@@ -18,7 +18,7 @@ IF[{- !$disabled{tests} -}]
           dtlsv1listentest ct_test threadstest afalgtest d2i_test \
           ssl_test_ctx_test ssl_test x509aux cipherlist_test asynciotest \
           bioprinttest sslapitest dtlstest sslcorrupttest bio_enc_test \
-          ocspapitest fatalerrtest
+          ocspapitest fatalerrtest x509_time_test
 
   SOURCE[versions]=versions.c
   INCLUDE[versions]=../include
@@ -297,6 +297,10 @@ IF[{- !$disabled{tests} -}]
   INCLUDE[bio_enc_test]=../include
   DEPEND[bio_enc_test]=../libcrypto
 
+  SOURCE[x509_time_test]=x509_time_test.c testutil.c
+  INCLUDE[x509_time_test]=.. ../include
+  DEPEND[x509_time_test]=../libcrypto
+
   IF[{- !$disabled{shared} -}]
     PROGRAMS_NO_INST=shlibloadtest
     SOURCE[shlibloadtest]=shlibloadtest.c
diff --git a/test/recipes/60-test_x509_time.t b/test/recipes/60-test_x509_time.t
new file mode 100644
index 0000000000..8b311ad314
--- /dev/null
+++ b/test/recipes/60-test_x509_time.t
@@ -0,0 +1,12 @@
+#! /usr/bin/env perl
+# Copyright 2017 The OpenSSL Project Authors. All Rights Reserved.
+#
+# Licensed under the OpenSSL license (the "License").  You may not use
+# this file except in compliance with the License.  You can obtain a copy
+# in the file LICENSE in the source distribution or at
+# https://www.openssl.org/source/license.html
+
+
+use OpenSSL::Test::Simple;
+
+simple_test("test_x509_time", "x509_time_test");
diff --git a/test/x509_time_test.c b/test/x509_time_test.c
new file mode 100644
index 0000000000..bc7e4c2b9c
--- /dev/null
+++ b/test/x509_time_test.c
@@ -0,0 +1,212 @@
+/*
+ * Copyright 2017 The OpenSSL Project Authors. All Rights Reserved.
+ *
+ * Licensed under the OpenSSL license (the "License").  You may not use
+ * this file except in compliance with the License.  You can obtain a copy
+ * in the file LICENSE in the source distribution or at
+ * https://www.openssl.org/source/license.html
+ */
+
+/* Tests for X509 time functions */
+
+#include <string.h>
+#include <time.h>
+
+#include <openssl/asn1.h>
+#include <openssl/x509.h>
+#include "testutil.h"
+#include "e_os.h"
+
+typedef struct {
+    const char *data;
+    int type;
+    time_t cmp_time;
+    /* -1 if asn1_time <= cmp_time, 1 if asn1_time > cmp_time, 0 if error. */
+    int expected;
+} TESTDATA;
+
+static TESTDATA x509_cmp_tests[] = {
+    {
+        "20170217180154Z", V_ASN1_GENERALIZEDTIME,
+        /* The same in seconds since epoch. */
+        1487354514, -1,
+    },
+    {
+        "20170217180154Z", V_ASN1_GENERALIZEDTIME,
+        /* One second more. */
+        1487354515, -1,
+    },
+    {
+        "20170217180154Z", V_ASN1_GENERALIZEDTIME,
+        /* One second less. */
+        1487354513, 1,
+    },
+    /* Same as UTC time. */
+    {
+        "170217180154Z", V_ASN1_UTCTIME,
+        /* The same in seconds since epoch. */
+        1487354514, -1,
+    },
+    {
+        "170217180154Z", V_ASN1_UTCTIME,
+        /* One second more. */
+        1487354515, -1,
+    },
+    {
+        "170217180154Z", V_ASN1_UTCTIME,
+        /* One second less. */
+        1487354513, 1,
+    },
+    /* UTCTime from the 20th century. */
+    {
+        "990217180154Z", V_ASN1_UTCTIME,
+        /* The same in seconds since epoch. */
+        919274514, -1,
+    },
+    {
+        "990217180154Z", V_ASN1_UTCTIME,
+        /* One second more. */
+        919274515, -1,
+    },
+    {
+        "990217180154Z", V_ASN1_UTCTIME,
+        /* One second less. */
+        919274513, 1,
+    },
+    /* Various invalid formats. */
+    {
+        /* No trailing Z. */
+        "20170217180154", V_ASN1_GENERALIZEDTIME, 0, 0,
+    },
+    {
+        /* No trailing Z, UTCTime. */
+        "170217180154", V_ASN1_UTCTIME, 0, 0,
+    },
+    {
+        /* No seconds. */
+        "201702171801Z", V_ASN1_GENERALIZEDTIME, 0, 0,
+    },
+    {
+        /* No seconds, UTCTime. */
+        "1702171801Z", V_ASN1_UTCTIME, 0, 0,
+    },
+    {
+        /* Fractional seconds. */
+        "20170217180154.001Z", V_ASN1_GENERALIZEDTIME, 0, 0,
+    },
+    {
+        /* Fractional seconds, UTCTime. */
+        "170217180154.001Z", V_ASN1_UTCTIME, 0, 0,
+    },
+    {
+        /* Timezone offset. */
+        "20170217180154+0100", V_ASN1_GENERALIZEDTIME, 0, 0,
+    },
+    {
+        /* Timezone offset, UTCTime. */
+        "170217180154+0100", V_ASN1_UTCTIME, 0, 0,
+    },
+    {
+        /* Extra digits. */
+        "2017021718015400Z", V_ASN1_GENERALIZEDTIME, 0, 0,
+    },
+    {
+        /* Extra digits, UTCTime. */
+        "17021718015400Z", V_ASN1_UTCTIME, 0, 0,
+    },
+    {
+        /* Non-digits. */
+        "2017021718015aZ", V_ASN1_GENERALIZEDTIME, 0, 0,
+    },
+    {
+        /* Non-digits, UTCTime. */
+        "17021718015aZ", V_ASN1_UTCTIME, 0, 0,
+    },
+    {
+        /* Trailing garbage. */
+        "20170217180154Zlongtrailinggarbage", V_ASN1_GENERALIZEDTIME, 0, 0,
+    },
+    {
+        /* Trailing garbage, UTCTime. */
+        "170217180154Zlongtrailinggarbage", V_ASN1_UTCTIME, 0, 0,
+    },
+    {
+         /* Swapped type. */
+        "20170217180154Z", V_ASN1_UTCTIME, 0, 0,
+    },
+    {
+        /* Swapped type. */
+        "170217180154Z", V_ASN1_GENERALIZEDTIME, 0, 0,
+    },
+    {
+        /* Bad type. */
+        "20170217180154Z", V_ASN1_OCTET_STRING, 0, 0,
+    },
+};
+
+static int test_x509_cmp_time(int idx)
+{
+    ASN1_TIME t;
+    int result;
+
+    memset(&t, 0, sizeof(t));
+    t.type = x509_cmp_tests[idx].type;
+    t.data = (unsigned char*)(x509_cmp_tests[idx].data);
+    t.length = strlen(x509_cmp_tests[idx].data);
+
+    result = X509_cmp_time(&t, &x509_cmp_tests[idx].cmp_time);
+    if (result != x509_cmp_tests[idx].expected) {
+        fprintf(stderr, "test_x509_cmp_time(%d) failed: expected %d, got %d\n",
+                idx, x509_cmp_tests[idx].expected, result);
+        return 0;
+    }
+    return 1;
+}
+
+static int test_x509_cmp_time_current()
+{
+    time_t now = time(NULL);
+    /* Pick a day earlier and later, relative to any system clock. */
+    ASN1_TIME *asn1_before = NULL, *asn1_after = NULL;
+    int cmp_result, failed = 0;
+
+    asn1_before = ASN1_TIME_adj(NULL, now, -1, 0);
+    asn1_after = ASN1_TIME_adj(NULL, now, 1, 0);
+
+    cmp_result  = X509_cmp_time(asn1_before, NULL);
+    if (cmp_result != -1) {
+        fprintf(stderr, "test_x509_cmp_time_current failed: expected -1, got %d\n",
+                cmp_result);
+        failed = 1;
+    }
+
+    cmp_result = X509_cmp_time(asn1_after, NULL);
+    if (cmp_result != 1) {
+        fprintf(stderr, "test_x509_cmp_time_current failed: expected 1, got %d\n",
+                cmp_result);
+        failed = 1;
+    }
+
+    ASN1_TIME_free(asn1_before);
+    ASN1_TIME_free(asn1_after);
+
+    return failed == 0;
+}
+
+int main(int argc, char **argv)
+{
+    int ret = 0;
+    unsigned int idx;
+
+    if (!test_x509_cmp_time_current())
+        ret = 1;
+
+    for (idx=0 ; idx < OSSL_NELEM(x509_cmp_tests) ; ++idx) {
+        if (!test_x509_cmp_time(idx))
+            ret = 1;
+    }
+
+    if (ret == 0)
+        printf("PASS\n");
+    return ret;
+}