2006-04-28 10:51:19 +00:00
parent 51c3484a9f
commit 1029d84d23
514 changed files with 2 additions and 2 deletions
@@ -0,0 +1,694 @@
+/* Certification Authority (CA) support for IKE authentication
+ * Copyright (C) 2002-2004 Andreas Steffen, Zuercher Hochschule Winterthur
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * for more details.
+ *
+ * RCSID $Id: ca.c,v 1.10 2005/12/25 12:29:55 as Exp $
+ */
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+#include <dirent.h>
+#include <time.h>
+#include <sys/types.h>
+
+#include <freeswan.h>
+#include <freeswan/ipsec_policy.h>
+
+#include "constants.h"
+#include "defs.h"
+#include "log.h"
+#include "x509.h"
+#include "ca.h"
+#include "certs.h"
+#include "whack.h"
+#include "fetch.h"
+
+/* chained list of X.509 authority certificates (ca, aa, and ocsp) */
+
+static x509cert_t *x509authcerts = NULL;
+
+const ca_info_t empty_ca_info = {
+      NULL	  ,  /* next */
+      NULL	  ,  /* name */
+    UNDEFINED_TIME,
+    { NULL, 0 }	  ,  /* authName */
+    { NULL, 0 }	  ,  /* authKeyID */
+    { NULL, 0 }	  ,  /* authKey SerialNumber */
+      NULL	  ,  /* ldaphost */
+      NULL	  ,  /* ldapbase */
+      NULL	  ,  /* ocspori */
+      NULL	  ,  /* crluri */
+      FALSE	     /* strictcrlpolicy */
+};
+
+/* chained list of X.509 certification authority information records */
+
+static ca_info_t *ca_infos = NULL;
+
+/*
+ * Checks if CA a is trusted by CA b
+ */
+bool
+trusted_ca(chunk_t a, chunk_t b, int *pathlen)
+{
+    bool match = FALSE;
+
+    /* no CA b specified -> any CA a is accepted */
+    if (b.ptr == NULL)
+    {
+	*pathlen = (a.ptr == NULL)? 0 : MAX_CA_PATH_LEN;
+	return TRUE;
+    }
+
+    /* no CA a specified -> trust cannot be established */
+    if (a.ptr == NULL)
+    {
+	*pathlen = MAX_CA_PATH_LEN;
+	return FALSE;
+    }
+
+    *pathlen = 0;
+
+    /* CA a equals CA b -> we have a match */
+    if (same_dn(a, b))
+	return TRUE;
+
+    /* CA a might be a subordinate CA of b */
+    lock_authcert_list("trusted_ca");
+
+    while ((*pathlen)++ < MAX_CA_PATH_LEN)
+    {
+	x509cert_t *cacert = get_authcert(a, empty_chunk, empty_chunk, AUTH_CA);
+
+	/* cacert not found or self-signed root cacert-> exit */
+	if (cacert == NULL || same_dn(cacert->issuer, a))
+	    break;
+
+	/* does the issuer of CA a match CA b? */
+	match = same_dn(cacert->issuer, b);
+
+	/* we have a match and exit the loop */
+	if (match)
+	    break;
+
+	/* go one level up in the CA chain */
+	a = cacert->issuer;
+    }
+    
+    unlock_authcert_list("trusted_ca");
+    return match;
+}
+
+/*
+ * does our CA match one of the requested CAs?
+ */
+bool
+match_requested_ca(generalName_t *requested_ca, chunk_t our_ca, int *our_pathlen)
+{
+    /* if no ca is requested than any ca will match */
+    if (requested_ca == NULL)
+    {
+	*our_pathlen = 0;
+	return TRUE;
+    }
+
+    *our_pathlen = MAX_CA_PATH_LEN + 1;
+
+    while (requested_ca != NULL)
+    {
+	int pathlen;
+
+	if (trusted_ca(our_ca, requested_ca->name, &pathlen)
+	&& pathlen < *our_pathlen)
+	    *our_pathlen = pathlen;
+	requested_ca = requested_ca->next;
+    }
+
+    return *our_pathlen <= MAX_CA_PATH_LEN;
+}
+
+/*
+ *  free the first authority certificate in the chain
+ */
+static void
+free_first_authcert(void)
+{
+    x509cert_t *first = x509authcerts;
+    x509authcerts = first->next;
+    free_x509cert(first);
+}
+
+/*
+ *  free  all CA certificates
+ */
+void
+free_authcerts(void)
+{
+    lock_authcert_list("free_authcerts");
+
+    while (x509authcerts != NULL)
+        free_first_authcert();
+
+    unlock_authcert_list("free_authcerts");
+}
+
+/*
+ *  get a X.509 authority certificate with a given subject or keyid
+ */
+x509cert_t*
+get_authcert(chunk_t subject, chunk_t serial, chunk_t keyid, u_char auth_flags)
+{
+    x509cert_t *cert = x509authcerts;
+    x509cert_t *prev_cert = NULL;
+
+    while (cert != NULL)
+    {
+	if (cert->authority_flags & auth_flags
+	&& ((keyid.ptr != NULL) ? same_keyid(keyid, cert->subjectKeyID)
+	    : (same_dn(subject, cert->subject)
+	       && same_serial(serial, cert->serialNumber))))
+	{
+	    if (cert != x509authcerts)
+	    {
+		/* bring the certificate up front */
+		prev_cert->next = cert->next;
+		cert->next = x509authcerts;
+		x509authcerts = cert;
+	    }
+	    return cert;
+	}
+	prev_cert = cert;
+	cert = cert->next;
+    }
+    return NULL;
+}
+
+/*
+ * add an authority certificate to the chained list
+ */
+bool
+add_authcert(x509cert_t *cert, u_char auth_flags)
+{
+    x509cert_t *old_cert;
+
+    /* set authority flags */
+    cert->authority_flags |= auth_flags;
+
+    lock_authcert_list("add_authcert");
+
+    old_cert = get_authcert(cert->subject, cert->serialNumber
+	, cert->subjectKeyID, auth_flags);
+
+    if (old_cert != NULL)
+    {
+	if (same_x509cert(cert, old_cert))
+	{
+	    /* cert is already present, just add additional authority flags */
+	    old_cert->authority_flags |= cert->authority_flags;
+	    DBG(DBG_CONTROL | DBG_PARSING ,
+		DBG_log("  authcert is already present and identical")
+	    )
+	    unlock_authcert_list("add_authcert");
+
+	    free_x509cert(cert);
+	    return FALSE;
+	}
+	else
+	{
+	    /* cert is already present but will be replaced by new cert */
+	    free_first_authcert();
+	    DBG(DBG_CONTROL | DBG_PARSING ,
+		DBG_log("  existing authcert deleted")
+	    )
+	}
+    }
+
+    /* add new authcert to chained list */
+    cert->next = x509authcerts;
+    x509authcerts = cert;
+    share_x509cert(cert);  /* set count to one */
+    DBG(DBG_CONTROL | DBG_PARSING,
+	DBG_log("  authcert inserted")
+    )
+    unlock_authcert_list("add_authcert");
+    return TRUE;
+}
+
+/*
+ *  Loads authority certificates
+ */
+void
+load_authcerts(const char *type, const char *path, u_char auth_flags)
+{
+    struct dirent **filelist;
+    u_char buf[BUF_LEN];
+    u_char *save_dir;
+    int n;
+
+    /* change directory to specified path */
+    save_dir = getcwd(buf, BUF_LEN);
+
+    if (chdir(path))
+    {
+	plog("Could not change to directory '%s'", path);
+    }
+    else
+    {
+	plog("Changing to directory '%s'", path);
+	n = scandir(path, &filelist, file_select, alphasort);
+
+	if (n < 0)
+	    plog("  scandir() error");
+	else
+	{
+	    while (n--)
+	    {
+		cert_t cert;
+
+		if (load_cert(filelist[n]->d_name, type, &cert))
+		    add_authcert(cert.u.x509, auth_flags);
+
+		free(filelist[n]);
+	    }
+	    free(filelist);
+	}
+    }
+    /* restore directory path */
+    chdir(save_dir);
+}
+
+/*
+ *  list all X.509 authcerts with given auth flags in a chained list
+ */
+void
+list_authcerts(const char *caption, u_char auth_flags, bool utc)
+{
+    lock_authcert_list("list_authcerts");
+    list_x509cert_chain(caption, x509authcerts, auth_flags, utc);
+    unlock_authcert_list("list_authcerts");
+}
+
+/*
+ * get a cacert with a given subject or keyid from an alternative list
+ */
+static const x509cert_t*
+get_alt_cacert(chunk_t subject, chunk_t serial, chunk_t keyid
+    , const x509cert_t *cert)
+{
+    while (cert != NULL)
+    {
+	if ((keyid.ptr != NULL) ? same_keyid(keyid, cert->subjectKeyID)
+	    : (same_dn(subject, cert->subject)
+	       && same_serial(serial, cert->serialNumber)))
+	{
+	    return cert;
+	}
+	cert = cert->next;
+    }
+    return NULL;
+}
+
+/* establish trust into a candidate authcert by going up the trust chain.
+ * validity and revocation status are not checked.
+ */
+bool
+trust_authcert_candidate(const x509cert_t *cert, const x509cert_t *alt_chain)
+{
+    int pathlen;
+
+    lock_authcert_list("trust_authcert_candidate");
+
+    for (pathlen = 0; pathlen < MAX_CA_PATH_LEN; pathlen++)
+    {
+	const x509cert_t *authcert = NULL;
+	u_char buf[BUF_LEN];
+
+	DBG(DBG_CONTROL,
+	    dntoa(buf, BUF_LEN, cert->subject);
+	    DBG_log("subject: '%s'",buf);
+	    dntoa(buf, BUF_LEN, cert->issuer);
+	    DBG_log("issuer:  '%s'",buf);
+	    if (cert->authKeyID.ptr != NULL)
+	    {
+		datatot(cert->authKeyID.ptr, cert->authKeyID.len, ':'
+		    , buf, BUF_LEN);
+		DBG_log("authkey:  %s", buf);
+	    }
+	)
+
+	/* search in alternative chain first */
+	authcert = get_alt_cacert(cert->issuer, cert->authKeySerialNumber
+	    , cert->authKeyID, alt_chain);
+
+	if (authcert != NULL)
+	{
+	    DBG(DBG_CONTROL,
+		DBG_log("issuer cacert found in alternative chain")
+	    )
+	}
+	else
+	{
+	    /* search in trusted chain */
+	    authcert = get_authcert(cert->issuer, cert->authKeySerialNumber
+		, cert->authKeyID, AUTH_CA);
+
+	    if (authcert != NULL)
+	    {
+		DBG(DBG_CONTROL,
+		    DBG_log("issuer cacert found")
+		)
+	    }
+	    else
+	    {
+		plog("issuer cacert not found");
+		unlock_authcert_list("trust_authcert_candidate");
+		return FALSE;
+	    }
+	}
+
+	if (!check_signature(cert->tbsCertificate, cert->signature
+			   , cert->algorithm, cert->algorithm, authcert))
+	{
+	    plog("certificate signature is invalid");
+	    unlock_authcert_list("trust_authcert_candidate");
+	    return FALSE;
+	}
+	DBG(DBG_CONTROL,
+	    DBG_log("certificate signature is valid")
+	)
+
+	/* check if cert is a self-signed root ca */
+	if (pathlen > 0 && same_dn(cert->issuer, cert->subject))
+	{
+	    DBG(DBG_CONTROL,
+		DBG_log("reached self-signed root ca")
+	    )
+	    unlock_authcert_list("trust_authcert_candidate");
+	    return TRUE;
+	}
+
+	/* go up one step in the trust chain */
+	cert = authcert;
+    }
+    plog("maximum ca path length of %d levels exceeded", MAX_CA_PATH_LEN);
+    unlock_authcert_list("trust_authcert_candidate");
+    return FALSE;
+}
+
+/*
+ *  get a CA info record with a given authName or authKeyID
+ */
+ca_info_t*
+get_ca_info(chunk_t authname, chunk_t serial, chunk_t keyid)
+{
+    ca_info_t *ca= ca_infos;
+
+    while (ca!= NULL)
+    {
+	if ((keyid.ptr != NULL) ? same_keyid(keyid, ca->authKeyID)
+	    : (same_dn(authname, ca->authName)
+	       && same_serial(serial, ca->authKeySerialNumber)))
+	{
+	    return ca;
+	}
+	ca = ca->next;
+    }
+    return NULL;
+}
+
+
+/*
+ *  free the dynamic memory used by a ca_info record
+ */
+static void
+free_ca_info(ca_info_t* ca_info)
+{
+    if (ca_info == NULL)
+	return;
+
+    pfreeany(ca_info->name);
+    pfreeany(ca_info->ldaphost);
+    pfreeany(ca_info->ldapbase);
+    pfreeany(ca_info->ocspuri);
+
+    freeanychunk(ca_info->authName);
+    freeanychunk(ca_info->authKeyID);
+    freeanychunk(ca_info->authKeySerialNumber);
+
+    free_generalNames(ca_info->crluri, TRUE);
+
+    pfree(ca_info);
+}
+
+/*
+ *  free  all CA certificates
+ */
+void
+free_ca_infos(void)
+{
+    while (ca_infos != NULL)
+    {
+	ca_info_t *ca = ca_infos;
+
+	ca_infos = ca_infos->next;
+	free_ca_info(ca);
+    }
+}
+
+/*
+ * find a CA information record by name and optionally delete it
+ */
+bool
+find_ca_info_by_name(const char *name, bool delete)
+{
+    ca_info_t **ca_p = &ca_infos;
+    ca_info_t *ca = *ca_p;
+
+    while (ca != NULL)
+    {
+	/* is there already an entry? */
+	if (streq(name, ca->name))
+	{
+	    if (delete)
+	    {
+		lock_ca_info_list("find_ca_info_by_name");
+		*ca_p = ca->next;
+		free_ca_info(ca);
+		plog("deleting ca description \"%s\"", name);
+		unlock_ca_info_list("find_ca_info_by_name");
+	    }
+	    return TRUE;
+	}
+	ca_p = &ca->next;
+	ca = *ca_p;
+    }
+    return FALSE;
+}
+
+
+ /*
+ * adds a CA description to a chained list
+ */
+void
+add_ca_info(const whack_message_t *msg)
+{
+    smartcard_t *sc = NULL;
+    cert_t cert;
+    bool valid_cert = FALSE;
+    bool cached_cert = FALSE;
+
+    if (find_ca_info_by_name(msg->name, FALSE))
+    {
+	loglog(RC_DUPNAME, "attempt to redefine ca record \"%s\"", msg->name);
+	return;
+    }
+
+    if (scx_on_smartcard(msg->cacert))
+    {
+	/* load CA cert from smartcard */
+	valid_cert = scx_load_cert(msg->cacert, &sc, &cert, &cached_cert);
+    }
+    else
+    {
+	/* load CA cert from file */
+	valid_cert = load_ca_cert(msg->cacert, &cert);
+    }
+
+    if (valid_cert)
+    {
+	char buf[BUF_LEN];
+	x509cert_t *cacert = cert.u.x509;
+	ca_info_t *ca = NULL;
+
+	/* does the authname already exist? */
+	ca = get_ca_info(cacert->subject, cacert->serialNumber
+		, cacert->subjectKeyID);
+	
+	if (ca != NULL)
+	{
+	    /* ca_info is already present */
+	    loglog(RC_DUPNAME, "  duplicate ca information in record \"%s\" found,"
+			       "ignoring \"%s\"", ca->name, msg->name);
+	    free_x509cert(cacert);
+	    return;
+	}
+
+	plog("added ca description \"%s\"", msg->name);
+
+	/* create and initialize new ca_info record */
+	ca = alloc_thing(ca_info_t, "ca info");
+	*ca = empty_ca_info;
+
+	/* name */
+	ca->name = clone_str(msg->name, "ca name");
+	    
+	/* authName */
+	clonetochunk(ca->authName, cacert->subject.ptr
+	    , cacert->subject.len, "authName");
+	dntoa(buf, BUF_LEN, ca->authName);
+	DBG(DBG_CONTROL,
+	    DBG_log("authname: '%s'", buf)
+	)
+
+	/* authSerialNumber */
+	clonetochunk(ca->authKeySerialNumber, cacert->serialNumber.ptr
+	    , cacert->serialNumber.len, "authKeySerialNumber");
+
+	/* authKeyID */
+	if (cacert->subjectKeyID.ptr != NULL)
+	{
+	    clonetochunk(ca->authKeyID, cacert->subjectKeyID.ptr
+		, cacert->subjectKeyID.len, "authKeyID");
+	    datatot(cacert->subjectKeyID.ptr, cacert->subjectKeyID.len, ':'
+		, buf, BUF_LEN);
+	    DBG(DBG_CONTROL | DBG_PARSING ,
+		DBG_log("authkey:  %s", buf)
+	    )
+	}
+
+	/* ldaphost */
+	ca->ldaphost = clone_str(msg->ldaphost, "ldaphost");
+
+	/* ldapbase */
+	ca->ldapbase = clone_str(msg->ldapbase, "ldapbase");
+
+	/* ocspuri */
+	if (msg->ocspuri != NULL)
+	{
+	    if (strncasecmp(msg->ocspuri, "http", 4) == 0)
+		ca->ocspuri = clone_str(msg->ocspuri, "ocspuri");
+	    else
+		plog("  ignoring ocspuri with unkown protocol");
+	}
+
+	/* crluri2*/
+	if (msg->crluri2 != NULL)
+	{
+	    generalName_t gn =
+		{ NULL, GN_URI, {msg->crluri2, strlen(msg->crluri2)} };
+
+	    add_distribution_points(&gn, &ca->crluri);
+	}
+
+	/* crluri */
+	if (msg->crluri != NULL)
+	{
+	    generalName_t gn =
+		{ NULL, GN_URI, {msg->crluri, strlen(msg->crluri)} };
+
+	    add_distribution_points(&gn, &ca->crluri);
+	}
+
+	/* strictrlpolicy */
+	ca->strictcrlpolicy = msg->whack_strict;
+
+	/* insert ca_info record into the chained list */
+	lock_ca_info_list("add_ca_info");
+
+	ca->next = ca_infos;
+	ca_infos = ca;
+	ca->installed = time(NULL);
+	
+	unlock_ca_info_list("add_ca_info");
+
+	/* add cacert to list of authcerts */
+	if (!cached_cert)
+	{
+	    if (add_authcert(cacert, AUTH_CA) && sc != NULL)
+	    {
+		if (sc->last_cert.type == CERT_X509_SIGNATURE)
+		    sc->last_cert.u.x509->count--;
+		sc->last_cert = cert;
+		share_cert(sc->last_cert);
+	    }
+	}
+	if (sc != NULL)
+	    time(&sc->last_load);
+    }
+}
+
+/*
+ * list all ca_info records in the chained list
+ */
+void
+list_ca_infos(bool utc)
+{
+    ca_info_t *ca = ca_infos;
+    
+    if (ca != NULL)
+    {
+	whack_log(RC_COMMENT, " ");
+	whack_log(RC_COMMENT, "List of X.509 CA Information Records:");
+	whack_log(RC_COMMENT, " ");
+    }
+
+    while (ca != NULL)
+    {
+	u_char buf[BUF_LEN];
+
+	/* strictpolicy per CA not supported yet
+	 *
+	whack_log(RC_COMMENT, "%s, \"%s\", strictcrlpolicy: %s"
+		, timetoa(&ca->installed, utc), ca->name
+		, ca->strictcrlpolicy? "yes":"no");
+	*/
+	whack_log(RC_COMMENT, "%s, \"%s\"", timetoa(&ca->installed, utc), ca->name);
+	dntoa(buf, BUF_LEN, ca->authName);
+	whack_log(RC_COMMENT, "       authname: '%s'", buf);
+	if (ca->ldaphost != NULL)
+	    whack_log(RC_COMMENT, "       ldaphost: '%s'", ca->ldaphost);
+	if (ca->ldapbase != NULL)
+	    whack_log(RC_COMMENT, "       ldapbase: '%s'", ca->ldapbase);
+	if (ca->ocspuri != NULL)
+	    whack_log(RC_COMMENT, "       ocspuri:  '%s'", ca->ocspuri);
+
+	list_distribution_points(ca->crluri);
+
+	if (ca->authKeyID.ptr != NULL)
+	{
+	    datatot(ca->authKeyID.ptr, ca->authKeyID.len, ':'
+		, buf, BUF_LEN);
+	    whack_log(RC_COMMENT, "       authkey:   %s", buf);
+	}
+	if (ca->authKeySerialNumber.ptr != NULL)
+	{
+	    datatot(ca->authKeySerialNumber.ptr, ca->authKeySerialNumber.len, ':'
+		, buf, BUF_LEN);
+	    whack_log(RC_COMMENT, "       aserial:   %s", buf);
+	}
+	ca = ca->next;
+    }
+}
+
+