Add ability to clamp a notafter to values representable in a 32 bit time_t

This will only be used in portable. As noted, necessary to
make us conformant to RFC 5280 4.1.2.5.
ok jsing@ bcook@

3 files changed, 41 insertions, 7 deletions

diff --git a/lib/libcrypto/asn1/a_time_tm.c b/lib/libcrypto/asn1/a_time_tm.c
index f0afc00be40..48f9f8b5e14 100644
--- a/lib/libcrypto/asn1/a_time_tm.c
+++ b/lib/libcrypto/asn1/a_time_tm.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: a_time_tm.c,v 1.12 2017/05/06 17:12:59 beck Exp $ */
+/* $OpenBSD: a_time_tm.c,v 1.13 2017/08/13 19:47:49 beck Exp $ */
 /*
  * Copyright (c) 2015 Bob Beck <beck@openbsd.org>
  *
@@ -58,6 +58,22 @@ ASN1_time_tm_cmp(struct tm *tm1, struct tm *tm2) {
 	return 0;
 }
 
+int
+ASN1_time_tm_clamp_notafter(struct tm *tm)
+{
+#ifdef SMALL_TIME_T
+	struct tm broken_os_epoch_tm;
+	time_t broken_os_epoch_time = INT_MAX;
+
+	if (gmtime_r(&broken_os_epoch_time, &broken_os_epoch_tm) == NULL)
+		return 0;
+
+	if (ASN1_time_tm_cmp(tm, &broken_os_epoch_tm) == 1)
+		memcpy(tm, &broken_os_epoch_tm, sizeof(*tm));
+#endif
+	return 1;
+}
+
 /* Format a time as an RFC 5280 format Generalized time */
 char *
 gentime_string_from_tm(struct tm *tm)
diff --git a/lib/libcrypto/asn1/asn1_locl.h b/lib/libcrypto/asn1/asn1_locl.h
index 17bb4157a9f..68f71dfc4aa 100644
--- a/lib/libcrypto/asn1/asn1_locl.h
+++ b/lib/libcrypto/asn1/asn1_locl.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: asn1_locl.h,v 1.8 2016/12/21 15:49:29 jsing Exp $ */
+/* $OpenBSD: asn1_locl.h,v 1.9 2017/08/13 19:47:49 beck Exp $ */
 /* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
  * project 2006.
  */
@@ -152,4 +152,6 @@ struct x509_crl_method_st {
 int UTF8_getc(const unsigned char *str, int len, unsigned long *val);
 int UTF8_putc(unsigned char *str, int len, unsigned long value);
 
+int ASN1_time_tm_clamp_notafter(struct tm *tm);
+
 __END_HIDDEN_DECLS
diff --git a/lib/libcrypto/x509/x509_vfy.c b/lib/libcrypto/x509/x509_vfy.c
index 0d01301446b..23ecf63d607 100644
--- a/lib/libcrypto/x509/x509_vfy.c
+++ b/lib/libcrypto/x509/x509_vfy.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: x509_vfy.c,v 1.64 2017/04/28 23:03:58 beck Exp $ */
+/* $OpenBSD: x509_vfy.c,v 1.65 2017/08/13 19:47:49 beck Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -73,8 +73,9 @@
 #include <openssl/objects.h>
 #include <openssl/x509.h>
 #include <openssl/x509v3.h>
-#include "x509_lcl.h"
+#include "asn1_locl.h"
 #include "vpm_int.h"
+#include "x509_lcl.h"
 
 /* CRL score values */
 
@@ -137,6 +138,8 @@ static int crl_crldp_check(X509 *x, X509_CRL *crl, int crl_score,
 static int check_crl_path(X509_STORE_CTX *ctx, X509 *x);
 static int check_crl_chain(X509_STORE_CTX *ctx, STACK_OF(X509) *cert_path,
     STACK_OF(X509) *crl_path);
+static int X509_cmp_time_internal(const ASN1_TIME *ctm, time_t *cmp_time,
+    int clamp_notafter);
 
 static int internal_verify(X509_STORE_CTX *ctx);
 
@@ -1745,7 +1748,7 @@ x509_check_cert_time(X509_STORE_CTX *ctx, X509 *x, int depth)
 		X509_V_ERR_CERT_NOT_YET_VALID))
 		return 0;
 
-	i = X509_cmp_time(X509_get_notAfter(x), ptime);
+	i = X509_cmp_time_internal(X509_get_notAfter(x), ptime, 1);
 	if (i <= 0 && depth < 0)
 		return 0;
 	if (i == 0 && !verify_cb_cert(ctx, x, depth,
@@ -1852,8 +1855,8 @@ X509_cmp_current_time(const ASN1_TIME *ctm)
  * 1 if the ASN1_time is later than *cmp_time.
  * 0 on error.
  */
-int
-X509_cmp_time(const ASN1_TIME *ctm, time_t *cmp_time)
+static int
+X509_cmp_time_internal(const ASN1_TIME *ctm, time_t *cmp_time, int clamp_notafter)
 {
 	time_t time1, time2;
 	struct tm tm1, tm2;
@@ -1877,6 +1880,12 @@ X509_cmp_time(const ASN1_TIME *ctm, time_t *cmp_time)
 	if (tm1.tm_year >= 150 && type != V_ASN1_GENERALIZEDTIME)
 		goto out;
 
+	if (clamp_notafter) {
+		/* Allow for completely broken operating systems. */
+		if (!ASN1_time_tm_clamp_notafter(&tm1))
+			goto out;
+	}
+
 	/*
 	 * Defensively fail if the time string is not representable as
 	 * a time_t. A time_t must be sane if you care about times after
@@ -1895,6 +1904,13 @@ X509_cmp_time(const ASN1_TIME *ctm, time_t *cmp_time)
 	return (ret);
 }
 
+int
+X509_cmp_time(const ASN1_TIME *ctm, time_t *cmp_time)
+{
+	return X509_cmp_time_internal(ctm, cmp_time, 0);
+}
+
+
 ASN1_TIME *
 X509_gmtime_adj(ASN1_TIME *s, long adj)
 {