/* $OpenBSD: x509.c,v 1.12 1999/07/17 21:54:39 niklas Exp $ */ /* $EOM: x509.c,v 1.17 1999/07/17 20:44:12 niklas Exp $ */ /* * Copyright (c) 1998, 1999 Niels Provos. All rights reserved. * Copyright (c) 1999 Niklas Hallqvist. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by Ericsson Radio Systems. * 4. The name of the author may not be used to endorse or promote products * derived from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ /* * This code was written under funding by Ericsson Radio Systems. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include "sysdep.h" #include "conf.h" #include "exchange.h" #include "hash.h" #include "ike_auth.h" #include "sa.h" #include "ipsec.h" #include "log.h" #include "x509.h" /* * X509_STOREs do not support subjectAltNames, so we have to build * our own hash table. */ /* * XXX Actually this store is not really useful, we never use it as we have * our own hash table. It also gets collisons if we have several certificates * only differing in subjectAltName. */ static X509_STORE *x509_certs; static X509_STORE *x509_cas; /* Initial number of bits used as hash. */ #define INITIAL_BUCKET_BITS 6 struct x509_hash { LIST_ENTRY (x509_hash) link; X509 *cert; }; static LIST_HEAD (x509_list, x509_hash) *x509_tab; /* Works both as a maximum index and a mask. */ static int bucket_mask; u_int16_t x509_hash (u_int8_t *id, size_t len) { int i; u_int16_t bucket = 0; /* XXX We might resize if we are crossing a certain threshold. */ len &= ~2; for (i = 0; i < len; i += 2) { /* Doing it this way avoids alignment problems. */ bucket ^= (id[i] + 1) * (id[i + 1] + 257); } bucket &= bucket_mask; return bucket; } void x509_hash_init () { int i; bucket_mask = (1 << INITIAL_BUCKET_BITS) - 1; x509_tab = malloc ((bucket_mask + 1) * sizeof (struct x509_list)); if (!x509_tab) log_fatal ("x509_hash_init: malloc (%d) failed", (bucket_mask + 1) * sizeof (struct x509_list)); for (i = 0; i <= bucket_mask; i++) { LIST_INIT (&x509_tab[i]); } } /* Lookup a certificate by an ID blob. */ X509 * x509_hash_find (u_int8_t *id, size_t len) { struct x509_hash *cert; u_int8_t *cid; size_t clen; for (cert = LIST_FIRST (&x509_tab[x509_hash (id, len)]); cert; cert = LIST_NEXT (cert, link)) { if (!x509_cert_get_subject (cert->cert, &cid, &clen)) continue; if (clen != len || memcmp (id, cid, len) != 0) { free (cid); continue; } free (cid); log_debug (LOG_CRYPTO, 70, "x509_hash_find: return X509 %p", cert->cert); return cert->cert; } log_debug (LOG_CRYPTO, 70, "x509_hash_find: no certificate matched query"); return 0; } int x509_hash_enter (X509 *cert) { u_int16_t bucket = 0; u_int8_t *id; u_int32_t len; struct x509_hash *certh; if (!x509_cert_get_subject (cert, &id, &len)) { log_print ("x509_hash_enter: can not retrieve subjectAltName"); return 0; } certh = malloc (sizeof *certh); if (!certh) { free (id); log_error ("x509_hash_enter: malloc (%d) failed", sizeof *certh); return 0; } memset (certh, 0, sizeof *certh); certh->cert = cert; bucket = x509_hash (id, len); free (id); LIST_INSERT_HEAD (&x509_tab[bucket], certh, link); log_debug (LOG_CRYPTO, 70, "x509_hash_enter: cert %p added to bucket %d", cert, bucket); return 1; } /* X509 Certificate Handling functions. */ int x509_read_from_dir (X509_STORE *ctx, char *name, int hash) { DIR *dir; struct dirent *file; BIO *certh; X509 *cert; char fullname[PATH_MAX]; int off, size; if (strlen (name) >= sizeof fullname - 1) { log_print ("x509_read_from_dir: directory name too long"); return 0; } log_debug (LOG_CRYPTO, 40, "x509_read_from_dir: reading certs from %s", name); dir = opendir (name); if (!dir) { log_error ("x509_read_from_dir: opendir (\"%s\") failed", name); return 0; } strncpy (fullname, name, sizeof fullname - 1); fullname[sizeof fullname - 1] = 0; off = strlen (fullname); size = sizeof fullname - off - 1; while ((file = readdir (dir)) != NULL) { if (file->d_type != DT_REG && file->d_type != DT_LNK) continue; log_debug (LOG_CRYPTO, 60, "x509_read_from_dir: reading certificate %s", file->d_name); certh = BIO_new (BIO_s_file ()); if (!certh) { log_error ("x509_read_from_dir: BIO_new (BIO_s_file ()) failed"); continue; } strncpy (fullname + off, file->d_name, size); fullname[off + size] = 0; if (BIO_read_filename (certh, fullname) == -1) { BIO_free (certh); log_error ("x509_read_from_dir: BIO_read_filename () failed"); continue; } cert = PEM_read_bio_X509 (certh, NULL, NULL); BIO_free (certh); if (cert == NULL) { log_error ("x509_read_from_dir: PEM_read_bio_X509 (%s) failed", file->d_name); continue; } if (!X509_STORE_add_cert (ctx, cert)) { /* * This is actually expected if we have several certificates only * differing in subjectAltName, which is not an something that is * strange. Consider multi-homed machines. */ log_debug (LOG_CRYPTO, 50, "x509_read_from_dir: X509_STORE_add_cert (%s) failed", file->d_name); } if (hash && !x509_hash_enter (cert)) log_print ("x509_read_from_dir: X509_hash_enter (%s) failed", file->d_name); } closedir (dir); return 1; } /* Initialize our databases and load our own certificates. */ int x509_cert_init (void) { char *dirname; x509_hash_init (); /* Process client certificates we will accept. */ dirname = conf_get_str ("X509-certificates", "Cert-directory"); if (!dirname) { log_print ("x509_cert_init: no Cert-directory"); return 0; } x509_certs = X509_STORE_new (); if (!x509_certs) { log_print ("x509_cert_init: creating new X509_STORE failed"); return 0; } if (!x509_read_from_dir (x509_certs, dirname, 1)) { log_print ("x509_cert_init: x509_read_from_dir failed"); return 0; } /* Process CA certificates we will trust. */ dirname = conf_get_str ("X509-certificates", "CA-directory"); if (!dirname) { log_print ("x509_cert_init: no CA-directory"); return 0; } x509_cas = X509_STORE_new (); if (!x509_cas) { log_print ("x509_cert_init: creating new X509_STORE failed"); return 0; } if (!x509_read_from_dir (x509_cas, dirname, 0)) { log_print ("x509_cert_init: x509_read_from_dir failed"); return 0; } return 1; } void * x509_cert_get (u_int8_t *asn, u_int32_t len) { return x509_from_asn (asn, len); } int x509_cert_validate (void *scert) { X509_STORE_CTX csc; X509_NAME *issuer, *subject; X509 *cert = (X509 *)scert; EVP_PKEY *key; int res; /* * Validate the peer certificate by checking with the CA certificates we * trust. */ X509_STORE_CTX_init (&csc, x509_cas, cert, NULL); res = X509_verify_cert (&csc); X509_STORE_CTX_cleanup (&csc); /* Return if validation succeeded or self-signed certs are not accepted. */ if (res || !conf_get_str ("X509-certificates", "Accept-self-signed")) return res; issuer = X509_get_issuer_name (cert); subject = X509_get_subject_name (cert); if (!issuer || !subject || X509_name_cmp (issuer, subject)) return 0; key = X509_get_pubkey (cert); if (!key) return 0; if (X509_verify (cert, key) == -1) return 0; return 1; } int x509_cert_insert (void *scert) { X509 *cert = X509_dup ((X509 *)scert); int res; if (!cert) { log_print ("x509_cert_insert: X509_dup failed"); return 0; } res = x509_hash_enter (cert); if (!res) X509_free (cert); return res; } void x509_cert_free (void *cert) { X509_free ((X509 *)cert); } /* Validate the BER Encoding of a RDNSequence in the CERT_REQ payload. */ int x509_certreq_validate (u_int8_t *asn, u_int32_t len) { int res = 1; /* struct norm_type name = SEQOF ("issuer", RDNSequence); if (!asn_template_clone (&name, 1) || (asn = asn_decode_sequence (asn, len, &name)) == 0) { log_print ("x509_certreq_validate: can not decode 'acceptable CA' info"); res = 0; } asn_free (&name); */ /* XXX - not supported directly in SSL - later */ return res; } /* Decode the BER Encoding of a RDNSequence in the CERT_REQ payload. */ void * x509_certreq_decode (u_int8_t *asn, u_int32_t len) { /* XXX This needs to be done later. struct norm_type aca = SEQOF ("aca", RDNSequence); struct norm_type *tmp; struct x509_aca naca, *ret; if (!asn_template_clone (&aca, 1) || (asn = asn_decode_sequence (asn, len, &aca)) == 0) { log_print ("x509_certreq_validate: can not decode 'acceptable CA' info"); goto fail; } memset (&naca, 0, sizeof (naca)); tmp = asn_decompose ("aca.RelativeDistinguishedName.AttributeValueAssertion", &aca); if (!tmp) goto fail; x509_get_attribval (tmp, &naca.name1); tmp = asn_decompose ("aca.RelativeDistinguishedName[1]" ".AttributeValueAssertion", &aca); if (tmp) x509_get_attribval (tmp, &naca.name2); asn_free (&aca); ret = malloc (sizeof (struct x509_aca)); if (ret) memcpy (ret, &naca, sizeof (struct x509_aca)); else { log_error ("x509_certreq_decode: malloc (%d) failed", sizeof (struct x509_aca)); x509_free_aca (&aca); } return ret; fail: asn_free (&aca); */ return 0; } void x509_free_aca (void *blob) { struct x509_aca *aca = blob; if (aca->name1.type) free (aca->name1.type); if (aca->name1.val) free (aca->name1.val); if (aca->name2.type) free (aca->name2.type); if (aca->name2.val) free (aca->name2.val); } X509 * x509_from_asn (u_char *asn, u_int len) { BIO *certh; X509 *scert = NULL; certh = BIO_new (BIO_s_mem ()); if (!certh) { log_error ("X509_from_asn: BIO_new (BIO_s_mem ()) failed"); return NULL; } if (BIO_write (certh, asn, len) == -1) { log_error ("X509_from_asn: BIO_write failed\n"); goto end; } scert = d2i_X509_bio (certh, NULL); if (!scert) { log_print ("X509_from_asn: d2i_X509_bio failed\n"); goto end; } end: BIO_free (certh); return scert; } /* * Check that a certificate has a subjectAltName and that it matches our ID. */ int x509_check_subjectaltname (u_char *id, u_int id_len, X509 *scert) { u_int8_t *altname; u_int32_t altlen; int type, idtype, ret; type = x509_cert_subjectaltname (scert, &altname, &altlen); if (!type) { log_print ("x509_check_subjectaltname: can't access subjectAltName"); return 0; } /* * Now that we have the X509 certicate in native form, get the * subjectAltName extension and verify that it matches our ID. */ /* XXX Get type of ID. */ idtype = id[0]; id += ISAKMP_ID_DATA_OFF - ISAKMP_GEN_SZ; id_len -= ISAKMP_ID_DATA_OFF - ISAKMP_GEN_SZ; ret = 0; switch (idtype) { case IPSEC_ID_IPV4_ADDR: if (type == X509v3_IPV4_ADDR) ret = 1; break; case IPSEC_ID_FQDN: if (type == X509v3_DNS_NAME) ret = 1; break; case IPSEC_ID_USER_FQDN: if (type == X509v3_RFC_NAME) ret = 1; break; default: ret = 0; break; } if (!ret) { log_debug (LOG_CRYPTO, 50, "X509_check_subjectaltname: " "our ID type does not match X509 cert ID type"); return 0; } if (altlen != id_len || memcmp (altname, id, id_len) != 0) { log_debug (LOG_CRYPTO, 50, "X509_check_subjectaltname: " "our ID does not match X509 cert ID"); return 0; } return 1; } /* * Obtain a certificate from an acceptable CA. * XXX We don't check if the certificate we find is from an accepted CA. */ int x509_cert_obtain (u_int8_t *id, size_t id_len, void *data, u_int8_t **cert, u_int32_t *certlen) { struct x509_aca *aca = data; X509 *scert; u_char *p; if (aca) log_debug (LOG_CRYPTO, 60, "x509_cert_obtain: acceptable certificate authorities here"); /* We need our ID to find a certificate. */ if (!id) { log_print ("X509_cert_obtain: ID is missing"); return 0; } scert = x509_hash_find (id, id_len); if (!scert) return 0; if (!x509_check_subjectaltname (id, id_len, scert)) { log_print ("X509_cert_obtain: subjectAltName does not match id"); free (*cert); return 0; } *certlen = i2d_X509 (scert, NULL); p = *cert = malloc (*certlen); if (!p) { log_error ("X509_cert_obtain: malloc (%d) failed", *certlen); return 0; } *certlen = i2d_X509 (scert, &p); return 1; } /* Returns a pointer to the subjectAltName information of X509 certificate. */ int x509_cert_subjectaltname (X509 *scert, u_int8_t **altname, u_int32_t *len) { X509_EXTENSION *subjectaltname; u_int8_t *sandata; int extpos; int santype, sanlen; extpos = X509_get_ext_by_NID (scert, NID_subject_alt_name, -1); if (extpos == -1) { log_print ("X509_cert_subjectaltname: " "certificate does not contain subjectAltName"); return 0; } subjectaltname = X509_get_ext (scert, extpos); if (!subjectaltname || !subjectaltname->value || !subjectaltname->value->data || subjectaltname->value->length < 4) { log_print ("X509_check_subjectaltname: " "invalid subjectaltname extension"); return 0; } /* SSL does not handle unknown ASN stuff well, do it by hand. */ sandata = subjectaltname->value->data; santype = sandata[2] & 0x3f; sanlen = sandata[3]; sandata += 4; if (sanlen + 4 != subjectaltname->value->length) { log_print ("X509_check_subjectaltname: subjectaltname invalid length"); return 0; } *len = sanlen; *altname = sandata; return santype; } int x509_cert_get_subject (void *scert, u_int8_t **id, u_int32_t *id_len) { X509 *cert = scert; int type; u_int8_t *altname; u_int32_t altlen; type = x509_cert_subjectaltname (cert, &altname, &altlen); switch (type) { case X509v3_IPV4_ADDR: { char buf[ISAKMP_ID_DATA_OFF + 4]; /* XXX sizeof IPV4_ADDR, how any better? */ if (altlen != 4) { log_print ("x509_cert_get_subject: length != IP4addr: %d", altlen); return 0; } SET_ISAKMP_ID_TYPE (buf, IPSEC_ID_IPV4_ADDR); SET_IPSEC_ID_PROTO (buf + ISAKMP_ID_DOI_DATA_OFF, 0); SET_IPSEC_ID_PORT (buf + ISAKMP_ID_DOI_DATA_OFF, 0); memcpy (buf + ISAKMP_ID_DATA_OFF, altname, altlen); *id_len = ISAKMP_ID_DATA_OFF + 4 - ISAKMP_GEN_SZ; *id = malloc (*id_len); if (!*id) { log_print ("x509_cert_get_subject: malloc (%d) failed", *id_len); return 0; } memcpy (*id, buf + ISAKMP_GEN_SZ, *id_len); } break; default: log_print ("x509_cert_get_subject: unsupported subjectAltName type: %d", type); return 0; } return 1; } int x509_cert_get_key (void *scert, void *keyp) { X509 *cert = scert; EVP_PKEY *key; key = X509_get_pubkey (cert); /* Check if we got the right key type */ if (key->type != EVP_PKEY_RSA) { log_print ("x509_cert_get_key: public key is not a RSA key"); X509_free (cert); return 0; } *(RSA **)keyp = RSAPublicKey_dup (key->pkey.rsa); return *(RSA **)keyp == NULL ? 0 : 1; }