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openssl-1_1/0002-Skip-CN-DNS-name-constraint-checks-when-not-needed.patch
Tomáš Chvátal 20fb199cba Accepting request 612812 from home:vitezslav_cizek:branches:security:tls 
- Relax CN name restrictions (bsc#1084011)
  * added patches:
    0001-Limit-scope-of-CN-name-constraints.patch
    0002-Skip-CN-DNS-name-constraint-checks-when-not-needed.patch

OBS-URL: https://build.opensuse.org/request/show/612812
OBS-URL: https://build.opensuse.org/package/show/security:tls/openssl-1_1?expand=0&rev=12
2018-05-29 09:17:53 +00:00

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From 6d3cfd13a904a03fc3522da935136dcdd12e9014 Mon Sep 17 00:00:00 2001
From: Viktor Dukhovni <openssl-users@dukhovni.org>
Date: Tue, 22 May 2018 14:46:02 -0400
Subject: [PATCH 2/2] Skip CN DNS name constraint checks when not needed
Only check the CN against DNS name contraints if the
`X509_CHECK_FLAG_NEVER_CHECK_SUBJECT` flag is not set, and either the
certificate has no DNS subject alternative names or the
`X509_CHECK_FLAG_ALWAYS_CHECK_SUBJECT` flag is set.
Add pertinent documentation, and touch up some stale text about
name checks and DANE.
Reviewed-by: Matt Caswell <matt@openssl.org>
Reviewed-by: Tim Hudson <tjh@openssl.org>
---
crypto/x509/x509_vfy.c | 28 ++++++++++++++++++-
crypto/x509v3/v3_ncons.c | 31 +++++++---------------
doc/crypto/X509_VERIFY_PARAM_set_flags.pod | 21 ++++++++++++---
doc/crypto/X509_check_host.pod | 7 +++--
doc/ssl/SSL_set1_host.pod | 2 +-
5 files changed, 61 insertions(+), 28 deletions(-)
Index: openssl-1.1.0h/crypto/x509/x509_vfy.c
===================================================================
--- openssl-1.1.0h.orig/crypto/x509/x509_vfy.c 2018-03-27 15:50:39.000000000 +0200
+++ openssl-1.1.0h/crypto/x509/x509_vfy.c 2018-05-29 10:52:23.753159887 +0200
@@ -557,6 +557,27 @@ static int check_chain_extensions(X509_S
return 1;
}
+static int has_san_id(X509 *x, int gtype)
+{
+ int i;
+ int ret = 0;
+ GENERAL_NAMES *gs = X509_get_ext_d2i(x, NID_subject_alt_name, NULL, NULL);
+
+ if (gs == NULL)
+ return 0;
+
+ for (i = 0; i < sk_GENERAL_NAME_num(gs); i++) {
+ GENERAL_NAME *g = sk_GENERAL_NAME_value(gs, i);
+
+ if (g->type == gtype) {
+ ret = 1;
+ break;
+ }
+ }
+ GENERAL_NAMES_free(gs);
+ return ret;
+}
+
static int check_name_constraints(X509_STORE_CTX *ctx)
{
int i;
@@ -655,7 +676,12 @@ static int check_name_constraints(X509_S
int rv = NAME_CONSTRAINTS_check(x, nc);
/* If EE certificate check commonName too */
- if (rv == X509_V_OK && i == 0)
+ if (rv == X509_V_OK && i == 0
+ && (ctx->param->hostflags
+ & X509_CHECK_FLAG_NEVER_CHECK_SUBJECT) == 0
+ && ((ctx->param->hostflags
+ & X509_CHECK_FLAG_ALWAYS_CHECK_SUBJECT) != 0
+ || !has_san_id(x, GEN_DNS)))
rv = NAME_CONSTRAINTS_check_CN(x, nc);
switch (rv) {
Index: openssl-1.1.0h/crypto/x509v3/v3_ncons.c
===================================================================
--- openssl-1.1.0h.orig/crypto/x509v3/v3_ncons.c 2018-05-29 10:52:23.733159579 +0200
+++ openssl-1.1.0h/crypto/x509v3/v3_ncons.c 2018-05-29 10:52:23.753159887 +0200
@@ -299,9 +299,9 @@ int NAME_CONSTRAINTS_check(X509 *x, NAME
static int cn2dnsid(ASN1_STRING *cn, unsigned char **dnsid, size_t *idlen)
{
- int utf8_length; /* Return type of ASN1_STRING_to_UTF8 */
- int i;
+ int utf8_length;
unsigned char *utf8_value;
+ int i;
int isdnsname = 0;
/* Don't leave outputs uninitialized */
@@ -337,8 +337,10 @@ static int cn2dnsid(ASN1_STRING *cn, uns
--utf8_length;
/* Reject *embedded* NULs */
- if ((size_t)utf8_length != strlen((char *)utf8_value))
- return X509_V_ERR_UNSPECIFIED;
+ if ((size_t)utf8_length != strlen((char *)utf8_value)) {
+ OPENSSL_free(utf8_value);
+ return X509_V_ERR_UNSUPPORTED_NAME_SYNTAX;
+ }
/*
* XXX: Deviation from strict DNS name syntax, also check names with '_'
@@ -388,11 +390,13 @@ static int cn2dnsid(ASN1_STRING *cn, uns
return X509_V_OK;
}
+/*
+ * Check CN against DNS-ID name constraints.
+ */
int NAME_CONSTRAINTS_check_CN(X509 *x, NAME_CONSTRAINTS *nc)
{
int r, i;
- GENERAL_NAMES *gens = NULL;
- X509_NAME *nm;
+ X509_NAME *nm = X509_get_subject_name(x);
ASN1_STRING stmp;
GENERAL_NAME gntmp;
@@ -401,21 +405,6 @@ int NAME_CONSTRAINTS_check_CN(X509 *x, N
gntmp.type = GEN_DNS;
gntmp.d.dNSName = &stmp;
- gens = X509_get_ext_d2i(x, NID_subject_alt_name, NULL, NULL);
- if (gens != NULL) {
- for (i = 0; i < sk_GENERAL_NAME_num(gens); i++) {
- GENERAL_NAME *gen = sk_GENERAL_NAME_value(gens, i);
-
- if (gen->type == GEN_DNS) {
- GENERAL_NAMES_free(gens);
- return X509_V_OK;
- }
- }
- GENERAL_NAMES_free(gens);
- }
-
- nm = X509_get_subject_name(x);
-
/* Process any commonName attributes in subject name */
for (i = -1;;) {
Index: openssl-1.1.0h/doc/crypto/X509_VERIFY_PARAM_set_flags.pod
===================================================================
--- openssl-1.1.0h.orig/doc/crypto/X509_VERIFY_PARAM_set_flags.pod 2018-03-27 15:50:40.000000000 +0200
+++ openssl-1.1.0h/doc/crypto/X509_VERIFY_PARAM_set_flags.pod 2018-05-29 10:52:23.753159887 +0200
@@ -130,14 +130,29 @@ B<name> clearing any previously specifie
B<name> is NULL, or empty the list of hostnames is cleared, and
name checks are not performed on the peer certificate. If B<name>
is NUL-terminated, B<namelen> may be zero, otherwise B<namelen>
-must be set to the length of B<name>. When a hostname is specified,
+must be set to the length of B<name>.
+
+When a hostname is specified,
certificate verification automatically invokes L<X509_check_host(3)>
with flags equal to the B<flags> argument given to
X509_VERIFY_PARAM_set_hostflags() (default zero). Applications
are strongly advised to use this interface in preference to explicitly
-calling L<X509_check_host(3)>, hostname checks are out of scope
+calling L<X509_check_host(3)>, hostname checks may be out of scope
with the DANE-EE(3) certificate usage, and the internal check will
-be suppressed as appropriate when DANE support is added to OpenSSL.
+be suppressed as appropriate when DANE verification is enabled.
+
+When the subject CommonName will not be ignored, whether as a result of the
+B<X509_CHECK_FLAG_ALWAYS_CHECK_SUBJECT> host flag, or because no DNS subject
+alternative names are present in the certificate, any DNS name constraints in
+issuer certificates apply to the subject CommonName as well as the subject
+alternative name extension.
+
+When the subject CommonName will be ignored, whether as a result of the
+B<X509_CHECK_FLAG_NEVER_CHECK_SUBJECT> host flag, or because some DNS subject
+alternative names are present in the certificate, DNS name constraints in
+issuer certificates will not be applied to the subject DN.
+As described in X509_check_host(3) the B<X509_CHECK_FLAG_NEVER_CHECK_SUBJECT>
+flag takes precendence over the B<X509_CHECK_FLAG_ALWAYS_CHECK_SUBJECT> flag.
X509_VERIFY_PARAM_add1_host() adds B<name> as an additional reference
identifier that can match the peer's certificate. Any previous names
Index: openssl-1.1.0h/doc/crypto/X509_check_host.pod
===================================================================
--- openssl-1.1.0h.orig/doc/crypto/X509_check_host.pod 2018-03-27 15:50:40.000000000 +0200
+++ openssl-1.1.0h/doc/crypto/X509_check_host.pod 2018-05-29 10:52:23.753159887 +0200
@@ -93,6 +93,9 @@ consider the subject DN even if the cert
names of the right type (DNS name or email address as appropriate); the default
is to use the subject DN when no corresponding subject alternative names are
present.
+If both B<X509_CHECK_FLAG_ALWAYS_CHECK_SUBJECT> and
+B<X509_CHECK_FLAG_NEVER_CHECK_SUBJECT> are specified, the latter takes
+precedence and the subject DN is not checked for matching names.
If set, B<X509_CHECK_FLAG_NO_WILDCARDS> disables wildcard
expansion; this only applies to B<X509_check_host>.
@@ -128,9 +131,9 @@ NULs.
Applications are encouraged to use X509_VERIFY_PARAM_set1_host()
rather than explicitly calling L<X509_check_host(3)>. Host name
-checks are out of scope with the DANE-EE(3) certificate usage,
+checks may be out of scope with the DANE-EE(3) certificate usage,
and the internal checks will be suppressed as appropriate when
-DANE support is added to OpenSSL.
+DANE support is enabled.
=head1 SEE ALSO
Index: openssl-1.1.0h/doc/ssl/SSL_set1_host.pod
===================================================================
--- openssl-1.1.0h.orig/doc/ssl/SSL_set1_host.pod 2018-03-27 15:50:40.000000000 +0200
+++ openssl-1.1.0h/doc/ssl/SSL_set1_host.pod 2018-05-29 10:52:23.753159887 +0200
@@ -56,7 +56,7 @@ is cleared or freed, or a renegotiation
must not free the return value.
SSL clients are advised to use these functions in preference to
-explicitly calling L<X509_check_host(3)>. Hostname checks are out
+explicitly calling L<X509_check_host(3)>. Hostname checks may be out
of scope with the RFC7671 DANE-EE(3) certificate usage, and the
internal check will be suppressed as appropriate when DANE is
enabled.
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