Re: Parsing X509 certificate subjectAltName
On 9/12/2012 9:36 AM, Dr. Stephen Henson wrote:
You check each value of the returned GENERAL_NAMES structure until you find
the one you are interested in. It looks like in your case it is the type
GEN_DIRNAME which means the X509_NAME field directoryName of the union is
relevant. You can then analyse that X509_NAME field e.g. like a certificate
subject name.
Here's the code I came up with - error checking, etc. removed for
brevity. It works. Would anyone care to critique it?
To review, here's what I'm trying to parse:
X509v3 Subject Alternative Name: critical
DirName:/2.23.133.2.1=id:xx00/2.23.133.2.2=Partname/2.23.133.2.3=id:version
int GetExtensions(X509 *x509Certificate)
{
STACK_OF(X509_EXTENSION) *exts;
int numExtensions;
GENERAL_NAMES *subjectAltNames =
(GENERAL_NAMES*) X509_get_ext_d2i(x509Certificate,
NID_subject_alt_name,
NULL, NULL);
int numberOfAlts = sk_GENERAL_NAME_num (subjectAltNames);
for ( i = 0; i < numberOfAlts ; i++) {
const GENERAL_NAME *pName =
sk_GENERAL_NAME_value (subjectAltNames, i);
if (pName->type == GEN_DIRNAME) {
X509_NAME *directoryName = (X509_NAME *)pName->d.dirn;
int entryCount = X509_NAME_entry_count(directoryName);
for (i = 0 ; i < entryCount ; i++) {
char asn1Object[256];
unsigned char *asn1ObjectValue = NULL;
X509_NAME_ENTRY *ent =
X509_NAME_get_entry(directoryName, i);
/* get the name, the OID */
ASN1_OBJECT *fn = X509_NAME_ENTRY_get_object(ent);
OBJ_obj2txt(asn1Object, sizeof asn1Object, fn, 1);
/* get the value, the text associated with OID name */
ASN1_STRING *val = X509_NAME_ENTRY_get_data(ent);
int length = ASN1_STRING_to_UTF8(&asn1ObjectValue, val);
}
}
}
}
__
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Automated List Manager majord...@openssl.org
Re: Parsing X509 certificate subjectAltName
On Wed, Sep 12, 2012, Kenneth Goldman wrote: > If I shouldn't use GEN_IPADD, what should I use? > > The goal is to extract the text value associated with several OIDs. > dumpasn1 says the values are PrintableString. > You check each value of the returned GENERAL_NAMES structure until you find the one you are interested in. It looks like in your case it is the type GEN_DIRNAME which means the X509_NAME field directoryName of the union is relevant. You can then analyse that X509_NAME field e.g. like a certificate subject name. Steve. -- Dr Stephen N. Henson. OpenSSL project core developer. Commercial tech support now available see: http://www.openssl.org __ OpenSSL Project http://www.openssl.org User Support Mailing Listopenssl-users@openssl.org Automated List Manager majord...@openssl.org
Re: Parsing X509 certificate subjectAltName
If I shouldn't use GEN_IPADD, what should I use?
The goal is to extract the text value associated with several OIDs.
dumpasn1 says the values are PrintableString.
--
Ken Goldman kgold...@us.ibm.com
914-945-2415 (862-2415)
From: "Dr. Stephen Henson"
To: openssl-users@openssl.org,
Date: 09/11/2012 06:49 PM
Subject: Re: Parsing X509 certificate subjectAltName
Sent by:owner-openssl-us...@openssl.org
On Tue, Sep 11, 2012, Charles Mills wrote:
>
> {
>
> case GEN_DNS:
>
> case GEN_URI:
>
> case GEN_IPADD:
>
>
> ASN1_STRING_to_UTF8(&pBuffer, pName->d.ia5);
>
> b =
> isWildcardedCNcompare(reinterpret_cast(pBuffer), nodeName);
>
>
Don't do that with the GEN_IPADD: it isn't an IA5String it is an
OCTETSTRING
representing the IP address in a format described by RFC3280 et al.
Steve.
--
Dr Stephen N. Henson. OpenSSL project core developer.
Commercial tech support now available see: http://www.openssl.org
__
OpenSSL Project http://www.openssl.org
User Support Mailing Listopenssl-users@openssl.org
Automated List Manager majord...@openssl.org
RE: Parsing X509 certificate subjectAltName
Thanks!
Charles
-Original Message-
From: owner-openssl-us...@openssl.org
[mailto:owner-openssl-us...@openssl.org] On Behalf Of Dr. Stephen Henson
Sent: Tuesday, September 11, 2012 3:46 PM
To: openssl-users@openssl.org
Subject: Re: Parsing X509 certificate subjectAltName
On Tue, Sep 11, 2012, Charles Mills wrote:
>
> {
>
> case GEN_DNS:
>
> case GEN_URI:
>
> case GEN_IPADD:
>
>
> ASN1_STRING_to_UTF8(&pBuffer, pName->d.ia5);
>
> b =
> isWildcardedCNcompare(reinterpret_cast(pBuffer), nodeName);
>
>
Don't do that with the GEN_IPADD: it isn't an IA5String it is an OCTETSTRING
representing the IP address in a format described by RFC3280 et al.
Steve.
--
Dr Stephen N. Henson. OpenSSL project core developer.
Commercial tech support now available see: http://www.openssl.org
__
OpenSSL Project http://www.openssl.org
User Support Mailing Listopenssl-users@openssl.org
Automated List Manager majord...@openssl.org
__
OpenSSL Project http://www.openssl.org
User Support Mailing Listopenssl-users@openssl.org
Automated List Manager majord...@openssl.org
Re: Parsing X509 certificate subjectAltName
On Tue, Sep 11, 2012, Charles Mills wrote:
>
> {
>
> case GEN_DNS:
>
> case GEN_URI:
>
> case GEN_IPADD:
>
>
> ASN1_STRING_to_UTF8(&pBuffer, pName->d.ia5);
>
> b =
> isWildcardedCNcompare(reinterpret_cast(pBuffer), nodeName);
>
>
Don't do that with the GEN_IPADD: it isn't an IA5String it is an OCTETSTRING
representing the IP address in a format described by RFC3280 et al.
Steve.
--
Dr Stephen N. Henson. OpenSSL project core developer.
Commercial tech support now available see: http://www.openssl.org
__
OpenSSL Project http://www.openssl.org
User Support Mailing Listopenssl-users@openssl.org
Automated List Manager majord...@openssl.org
RE: Parsing X509 certificate subjectAltName
bool Comm::isAltNameMatch(X509 *certificate, const char *nodeName)
{
// there is alternative code on page 136 of O'Reilly OpenSSL
unsigned char *pBuffer = NULL;
int length = 0;
GENERAL_NAMES *subjectAltNames;
bool b;
subjectAltNames = (GENERAL_NAMES*)
X509_get_ext_d2i(certificate, NID_subject_alt_name, NULL, NULL);
if ( subjectAltNames )
{
int numberOfAlts;
int i;
// get number of names. Supposed to be at
least one, but don't count on it
numberOfAlts = sk_GENERAL_NAME_num
(subjectAltNames);
// loop through all of the alternate names
for ( i = 0; i < numberOfAlts; i++)
{
// get a handle to
alternative name i
const GENERAL_NAME *pName =
sk_GENERAL_NAME_value (subjectAltNames, i);
// what did we get?
switch (pName->type)
{
case GEN_DNS:
case GEN_URI:
case GEN_IPADD:
ASN1_STRING_to_UTF8(&pBuffer, pName->d.ia5);
b =
isWildcardedCNcompare(reinterpret_cast(pBuffer), nodeName);
OPENSSL_free(pBuffer);
if ( b )
return true;
break;
case GEN_OTHERNAME:
case GEN_EMAIL:
case GEN_X400:
case GEN_DIRNAME:
case GEN_EDIPARTY:
case GEN_RID:
default:
break;
}
}
}
// fall through or no alt names
return false;
}
Charles
From: owner-openssl-us...@openssl.org
[mailto:owner-openssl-us...@openssl.org] On Behalf Of Kenneth Goldman
Sent: Tuesday, September 11, 2012 2:14 PM
To: openssl-users@openssl.org
Subject: Parsing X509 certificate subjectAltName
I'm 90% deep into parsing an X509 certificate, but I can't find sample code
for the last piece.
I found the extension, and located the ASN1_OBJECT with nid 85, OID
2.5.29.17, the subjectAltName. From the dumpasn output, I see that this is
an octet string of a sequence, etc.
I have to pull out the three OIDs '2.23.133.2. [1, 2, and 3]' which are
presumably in the ASN1_OBJECT.
Can anyone point me to sample code or a hint?
~~
515 3: . . . . . OBJECT IDENTIFIER subjectAltName (2 5 29 17)
: . . . . . . (X.509 extension)
<01 01 FF>
520 1: . . . . . BOOLEAN TRUE
<04 4A 30 48 A4 46 30 44 31 42 30 14 06 05 67 81 05 02 01 13 0B 69 64
3A>
523 74: . . . . . OCTET STRING, encapsulates {
<30 48 A4 46 30 44 31 42 30 14 06 05 67 81 05 02 01 13 0B 69 64 3A 35
37>
525 72: . . . . . . SEQUENCE {
527 70: . . . . . . . [4] {
<30 44 31 42 30 14 06 05 67 81 05 02 01 13 0B 69 64 3A 35 37 34 35 34
33>
529 68: . . . . . . . . SEQUENCE {
<31 42 30 14 06 05 67 81 05 02 01 13 0B 69 64 3A 35 37 34 35 34 33 30
30>
531 66: . . . . . . . . . SET {
<30 14 06 05 67 81 05 02 01 13 0B 69 64 3A 35 37 34 35 34 33 30 30>
533 20: . . . . . . . . . . SEQUENCE {
<06 05 67 81 05 02 01>
535 5: . . . . . . . . . . . OBJECT IDENTIFIER '2 23 133 2 1'
<13 0B 69 64 3A 35 37 34 35 34 33 30 30>
542 11: . . . . . . . . . . . PrintableString 'id:57454300'
: . . . . . . . . . . . }
<30 18 06 05 67 81 05 02 02 13 0F 4E 50 43 54 34 32 78 2F 4E 50 43 54
35>
555 24: . . . . . . . . . . SEQUENCE {
<06 05 67 81 05 02 02>
557 5: . . . . . . . . . . . OBJECT IDENTIFIER '2 23 133 2 2'
<13 0F 4E 50 43 54 34 32 78 2F 4E 50 43 54 35 30 78>
564 15: . . . . . . . . . . . PrintableString 'NPCT42x/NPCT50x'
: . . . . . . . . . . . }
<30 10 06 05 67 81 05 02 03 13 07 69 64 3A 30 33 39 31>
581 16: . . . . . . . . . . SEQUENCE {
<06 05 67 81 05 02 03>
583 5: . . . . . . . . . . . OBJECT IDENTIFIER '2 23 133 2 3'
<13 07 69 64 3A 30 33 39 31>
590 7: . . . . . . . . . . . PrintableString 'id:0391'
: . . . . . . .
