x509.h File Reference

X.509 certificates. More...

#include <stdint.h>

Go to the source code of this file.

Data Structures
struct	x509_rsa_public_key
	An X.509 RSA public key. More...
Functions
	FILE_LICENCE (GPL2_OR_LATER)
static void	x509_free_rsa_public_key (struct x509_rsa_public_key *rsa_pubkey)
	Free X.509 RSA public key.
int	x509_rsa_public_key (const struct asn1_cursor *certificate, struct x509_rsa_public_key *rsa_pubkey)
	Identify X.509 certificate RSA modulus and public exponent.

---

Detailed Description

X.509 certificates.

Definition in file x509.h.

---

Function Documentation

FILE_LICENCE

(

GPL2_OR_LATER

)

static void x509_free_rsa_public_key

(

struct x509_rsa_public_key *

rsa_pubkey

)

[inline, static]

Free X.509 RSA public key.

Parameters:

rsa_pubkey

RSA public key

Definition at line 34 of file x509.h.

References free(), and x509_rsa_public_key::modulus.

Referenced by free_tls().

                                                                    {
        free ( rsa_pubkey->modulus );
}

int x509_rsa_public_key	(	const struct asn1_cursor *	certificate,
		struct x509_rsa_public_key *	rsa_pubkey
	)

Identify X.509 certificate RSA modulus and public exponent.

Parameters:

	certificate	Certificate
	rsa	RSA public key to fill in

Return values:

rc

Return status code

The caller is responsible for eventually calling x509_free_rsa_public_key() to free the storage allocated to hold the RSA modulus and exponent.

Definition at line 104 of file x509.c.

References asn1_enter(), ASN1_INTEGER, ASN1_OID, ASN1_SEQUENCE, asn1_skip(), asn1_cursor::data, DBG, DBG2, DBG2_HDA, DBG_HDA, ENOMEM, ENOTSUP, x509_rsa_public_key::exponent, x509_rsa_public_key::exponent_len, asn1_cursor::len, malloc(), memcmp(), memcpy, x509_rsa_public_key::modulus, x509_rsa_public_key::modulus_len, oid_rsa_encryption, and x509_public_key().

                                                                   {
        struct asn1_cursor algorithm;
        struct asn1_cursor pubkey;
        struct asn1_cursor modulus;
        struct asn1_cursor exponent;
        int rc;

        /* First, extract the public key algorithm and key data */
        if ( ( rc = x509_public_key ( certificate, &algorithm,
                                      &pubkey ) ) != 0 )
                return rc;

        /* Check that algorithm is RSA */
        rc = ( asn1_enter ( &algorithm, ASN1_OID ) /* algorithm */ );
        if ( rc != 0 ) {
                DBG ( "Cannot locate algorithm:\n" );
                DBG_HDA ( 0, certificate->data, certificate->len );
        return rc;
        }
        if ( ( algorithm.len != sizeof ( oid_rsa_encryption ) ) ||
             ( memcmp ( algorithm.data, &oid_rsa_encryption,
                        sizeof ( oid_rsa_encryption ) ) != 0 ) ) {
                DBG ( "algorithm is not rsaEncryption in:\n" );
                DBG_HDA ( 0, certificate->data, certificate->len );
                return -ENOTSUP;
        }

        /* Check that public key is a byte string, i.e. that the
         * "unused bits" byte contains zero.
         */
        if ( ( pubkey.len < 1 ) ||
             ( ( *( uint8_t * ) pubkey.data ) != 0 ) ) {
                DBG ( "subjectPublicKey is not a byte string in:\n" );
                DBG_HDA ( 0, certificate->data, certificate->len );
                return -ENOTSUP;
        }
        pubkey.data++;
        pubkey.len--;

        /* Pick out the modulus and exponent */
        rc = ( asn1_enter ( &pubkey, ASN1_SEQUENCE ) /* RSAPublicKey */ );
        if ( rc != 0 ) {
                DBG ( "Cannot locate RSAPublicKey in:\n" );
                DBG_HDA ( 0, certificate->data, certificate->len );
                return -ENOTSUP;
        }
        memcpy ( &modulus, &pubkey, sizeof ( modulus ) );
        rc = ( asn1_enter ( &modulus, ASN1_INTEGER ) /* modulus */ );
        if ( rc != 0 ) {
                DBG ( "Cannot locate modulus in:\n" );
                DBG_HDA ( 0, certificate->data, certificate->len );
                return -ENOTSUP;
        }
        memcpy ( &exponent, &pubkey, sizeof ( exponent ) );
        rc = ( asn1_skip ( &exponent, ASN1_INTEGER ), /* modulus */
               asn1_enter ( &exponent, ASN1_INTEGER ) /* publicExponent */ );
        if ( rc != 0 ) {
                DBG ( "Cannot locate publicExponent in:\n" );
                DBG_HDA ( 0, certificate->data, certificate->len );
                return -ENOTSUP;
        }

        /* Allocate space and copy out modulus and exponent */
        rsa_pubkey->modulus = malloc ( modulus.len + exponent.len );
        if ( ! rsa_pubkey->modulus )
                return -ENOMEM;
        rsa_pubkey->exponent = ( rsa_pubkey->modulus + modulus.len );
        memcpy ( rsa_pubkey->modulus, modulus.data, modulus.len );
        rsa_pubkey->modulus_len = modulus.len;
        memcpy ( rsa_pubkey->exponent, exponent.data, exponent.len );
        rsa_pubkey->exponent_len = exponent.len;

        DBG2 ( "RSA modulus:\n" );
        DBG2_HDA ( 0, rsa_pubkey->modulus, rsa_pubkey->modulus_len );
        DBG2 ( "RSA exponent:\n" );
        DBG2_HDA ( 0, rsa_pubkey->exponent, rsa_pubkey->exponent_len );

        return 0;
}