root/sbin/iked/ca.c
/*      $OpenBSD: ca.c,v 1.105 2025/09/08 10:18:23 jsg Exp $    */

/*
 * Copyright (c) 2010-2013 Reyk Floeter <reyk@openbsd.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <sys/queue.h>
#include <sys/socket.h>
#include <sys/uio.h>

#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <dirent.h>
#include <string.h>
#include <signal.h>
#include <syslog.h>
#include <errno.h>
#include <err.h>
#include <event.h>

#include <openssl/bio.h>
#include <openssl/err.h>
#include <openssl/ssl.h>
#include <openssl/x509.h>
#include <openssl/x509v3.h>
#include <openssl/pem.h>
#include <openssl/evp.h>
#include <openssl/sha.h>
#include <openssl/rsa.h>

#include "iked.h"
#include "ikev2.h"

struct ca_store;

void     ca_run(struct privsep *, struct privsep_proc *, void *);
void     ca_shutdown(void);
void     ca_reset(struct iked *);
int      ca_reload(struct iked *);

int      ca_cert_local(struct iked *, X509 *);
int      ca_getreq(struct iked *, struct imsg *);
int      ca_getcert(struct iked *, struct imsg *);
int      ca_getauth(struct iked *, struct imsg *);
int      ca_load_cert_file(struct ca_store *, char *);
X509    *ca_by_subjectpubkey(X509_STORE *, uint8_t *, size_t);
X509    *ca_by_issuer(X509_STORE *, X509_NAME *, struct iked_static_id *);
X509    *ca_by_subjectaltname(X509_STORE *, struct iked_static_id *);
void     ca_store_certs_info(const char *, X509_STORE *);
int      ca_subjectpubkey_digest(X509 *, uint8_t *, unsigned int *);
int      ca_x509_subject_cmp(X509 *, struct iked_static_id *);
int      ca_validate_pubkey(struct iked *, struct iked_static_id *,
            void *, size_t, struct iked_id *);
int      ca_validate_cert(struct iked *, struct iked_static_id *,
            void *, size_t, STACK_OF(X509) *, X509 **);
EVP_PKEY *
         ca_bytes_to_pkey(uint8_t *, size_t);
int      ca_privkey_to_method(struct iked_id *);
struct ibuf *
         ca_x509_serialize(X509 *);
int      ca_x509_subjectaltname_do(X509 *, int, const char *,
            struct iked_static_id *, struct iked_id *);
int      ca_x509_subjectaltname_cmp(X509 *, struct iked_static_id *);
int      ca_x509_subjectaltname_log(X509 *, const char *);
int      ca_x509_subjectaltname_get(X509 *cert, struct iked_id *);
int      ca_dispatch_parent(int, struct privsep_proc *, struct imsg *);
int      ca_dispatch_ikev2(int, struct privsep_proc *, struct imsg *);
int      ca_dispatch_control(int, struct privsep_proc *, struct imsg *);
void     ca_store_info(struct iked *, struct imsg *, const char *, X509_STORE *);

static struct privsep_proc procs[] = {
        { "parent",     PROC_PARENT,    ca_dispatch_parent },
        { "ikev2",      PROC_IKEV2,     ca_dispatch_ikev2 },
        { "control",    PROC_CONTROL,   ca_dispatch_control }
};

struct ca_store {
        X509_STORE      *ca_cas;
        X509_LOOKUP     *ca_calookup;

        X509_STORE      *ca_certs;
        X509_LOOKUP     *ca_certlookup;

        struct iked_id   ca_privkey;
        struct iked_id   ca_pubkey;

        uint8_t          ca_privkey_method;
};

void
caproc(struct privsep *ps, struct privsep_proc *p)
{
        proc_run(ps, p, procs, nitems(procs), ca_run, NULL);
}

void
ca_run(struct privsep *ps, struct privsep_proc *p, void *arg)
{
        struct iked     *env = iked_env;
        struct ca_store *store;

        /*
         * pledge in the ca process:
         * stdio - for malloc and basic I/O including events.
         * rpath - for certificate files.
         * recvfd - for ocsp sockets.
         */
        if (pledge("stdio rpath recvfd", NULL) == -1)
                fatal("pledge");

        if ((store = calloc(1, sizeof(*store))) == NULL)
                fatal("%s: failed to allocate cert store", __func__);

        env->sc_priv = store;
        p->p_shutdown = ca_shutdown;
}

void
ca_shutdown(void)
{
        struct iked             *env = iked_env;
        struct ca_store         *store;

        ibuf_free(env->sc_certreq);
        if ((store = env->sc_priv) == NULL)
                return;
        X509_STORE_free(store->ca_cas);
        X509_STORE_free(store->ca_certs);
        ibuf_free(store->ca_pubkey.id_buf);
        ibuf_free(store->ca_privkey.id_buf);
        free(store);
}

void
ca_getkey(struct privsep *ps, struct iked_id *key, enum imsg_type type)
{
        struct iked     *env = iked_env;
        struct ca_store *store = env->sc_priv;
        struct iked_id  *id = NULL;
        const char      *name;

        if (store == NULL)
                fatalx("%s: invalid store", __func__);

        if (type == IMSG_PRIVKEY) {
                name = "private";
                id = &store->ca_privkey;

                store->ca_privkey_method = ca_privkey_to_method(key);
                if (store->ca_privkey_method == IKEV2_AUTH_NONE)
                        fatalx("ca: failed to get auth method for privkey");
        } else if (type == IMSG_PUBKEY) {
                name = "public";
                id = &store->ca_pubkey;
        } else
                fatalx("%s: invalid type %d", __func__, type);

        log_debug("%s: received %s key type %s length %zd", __func__,
            name, print_map(key->id_type, ikev2_cert_map),
            ibuf_length(key->id_buf));

        /* clear old key and copy new one */
        ibuf_free(id->id_buf);
        memcpy(id, key, sizeof(*id));
}

void
ca_reset(struct iked *env)
{
        struct ca_store *store = env->sc_priv;

        if (store->ca_privkey.id_type == IKEV2_ID_NONE ||
            store->ca_pubkey.id_type == IKEV2_ID_NONE)
                fatalx("ca_reset: keys not loaded");

        X509_STORE_free(store->ca_cas);
        X509_STORE_free(store->ca_certs);

        if ((store->ca_cas = X509_STORE_new()) == NULL)
                fatalx("ca_reset: failed to get ca store");
        if ((store->ca_calookup = X509_STORE_add_lookup(store->ca_cas,
            X509_LOOKUP_file())) == NULL)
                fatalx("ca_reset: failed to add ca lookup");

        if ((store->ca_certs = X509_STORE_new()) == NULL)
                fatalx("ca_reset: failed to get cert store");
        if ((store->ca_certlookup = X509_STORE_add_lookup(store->ca_certs,
            X509_LOOKUP_file())) == NULL)
                fatalx("ca_reset: failed to add cert lookup");

        if (ca_reload(env) != 0)
                fatal("ca_reset: reload");
}

int
ca_certbundle_add(struct ibuf *buf, struct iked_id *id)
{
        uint8_t          type = id->id_type;
        size_t           len = ibuf_size(id->id_buf);
        void            *val = ibuf_data(id->id_buf);

        if (buf == NULL ||
            ibuf_add(buf, &type, sizeof(type)) != 0 ||
            ibuf_add(buf, &len, sizeof(len)) != 0 ||
            ibuf_add(buf, val, len) != 0)
                return -1;
        return 0;
}

/*
 * decode cert bundle to cert and untrusted intermediate CAs.
 * datap/lenp point to bundle on input and to decoded cert output
 */
static int
ca_decode_cert_bundle(struct iked *env, struct iked_sahdr *sh,
  uint8_t **datap, size_t *lenp, STACK_OF(X509) **untrustedp)
{
        STACK_OF(X509)          *untrusted = NULL;
        X509                    *cert;
        BIO                     *rawcert = NULL;
        uint8_t                 *certdata = NULL;
        size_t                   certlen = 0;
        uint8_t                  datatype;
        size_t                   datalen = 0;
        uint8_t                 *ptr;
        size_t                   len;
        int                      ret = -1;

        log_debug("%s: decoding cert bundle", SPI_SH(sh, __func__));

        ptr = *datap;
        len = *lenp;
        *untrustedp = NULL;

        /* allocate stack for intermediate CAs */
        if ((untrusted = sk_X509_new_null()) == NULL)
                goto done;

        /* parse TLV, see ca_certbundle_add() */
        while (len > 0) {
                /* Type */
                if (len < sizeof(datatype)) {
                        log_debug("%s: short data (type)",
                            SPI_SH(sh, __func__));
                        goto done;
                }
                memcpy(&datatype, ptr, sizeof(datatype));
                ptr += sizeof(datatype);
                len -= sizeof(datatype);

                /* Only X509 certs/CAs are supported */
                if (datatype != IKEV2_CERT_X509_CERT) {
                        log_info("%s: unsupported data type: %s",
                            SPI_SH(sh, __func__),
                            print_map(datatype, ikev2_cert_map));
                        goto done;
                }

                /* Length */
                if (len < sizeof(datalen)) {
                        log_info("%s: short data (len)",
                            SPI_SH(sh, __func__));
                        goto done;
                }
                memcpy(&datalen, ptr, sizeof(datalen));
                ptr += sizeof(datalen);
                len -= sizeof(datalen);

                /* Value */
                if (len < datalen) {
                        log_info("%s: short len %zu < datalen %zu",
                            SPI_SH(sh, __func__), len, datalen);
                        goto done;
                }

                if (certdata == NULL) {
                        /* First entry is cert */
                        certdata = ptr;
                        certlen = datalen;
                } else {
                        /* All other entries are intermediate CAs */
                        rawcert = BIO_new_mem_buf(ptr, datalen);
                        if (rawcert == NULL)
                                goto done;
                        cert = d2i_X509_bio(rawcert, NULL);
                        BIO_free(rawcert);
                        if (cert == NULL) {
                                log_warnx("%s: cannot parse CA",
                                    SPI_SH(sh, __func__));
                                ca_sslerror(__func__);
                                goto done;
                        }
                        if (!sk_X509_push(untrusted, cert)) {
                                log_warnx("%s: cannot store CA",
                                    SPI_SH(sh, __func__));
                                X509_free(cert);
                                goto done;
                        }
                }
                ptr += datalen;
                len -= datalen;
        }
        log_debug("%s: decoded cert bundle", SPI_SH(sh, __func__));
        *datap = certdata;
        *lenp = certlen;
        *untrustedp = untrusted;
        untrusted = NULL;
        ret = 0;

 done:
        if (ret != 0)
                log_info("%s: failed to decode cert bundle",
                    SPI_SH(sh, __func__));
        sk_X509_pop_free(untrusted, X509_free);
        return ret;
}

int
ca_dispatch_parent(int fd, struct privsep_proc *p, struct imsg *imsg)
{
        struct iked             *env = iked_env;
        unsigned int             mode;

        switch (imsg->hdr.type) {
        case IMSG_CTL_ACTIVE:
        case IMSG_CTL_PASSIVE:
                /*
                 * send back to indicate we have processed
                 * all messages from parent.
                 */
                proc_compose(&env->sc_ps, PROC_PARENT, imsg->hdr.type, NULL, 0);
                break;
        case IMSG_CTL_RESET:
                IMSG_SIZE_CHECK(imsg, &mode);
                memcpy(&mode, imsg->data, sizeof(mode));
                if (mode == RESET_ALL || mode == RESET_CA) {
                        log_debug("%s: config reset", __func__);
                        ca_reset(env);
                }
                break;
        case IMSG_OCSP_FD:
                ocsp_receive_fd(env, imsg);
                break;
        case IMSG_OCSP_CFG:
                config_getocsp(env, imsg);
                break;
        case IMSG_PRIVKEY:
        case IMSG_PUBKEY:
                config_getkey(env, imsg);
                break;
        case IMSG_CTL_STATIC:
                config_getstatic(env, imsg);
                break;
        default:
                return (-1);
        }

        return (0);
}

int
ca_dispatch_ikev2(int fd, struct privsep_proc *p, struct imsg *imsg)
{
        struct iked     *env = iked_env;

        switch (imsg->hdr.type) {
        case IMSG_CERTREQ:
                ca_getreq(env, imsg);
                break;
        case IMSG_CERT:
                ca_getcert(env, imsg);
                break;
        case IMSG_AUTH:
                ca_getauth(env, imsg);
                break;
        default:
                return (-1);
        }

        return (0);
}

int
ca_dispatch_control(int fd, struct privsep_proc *p, struct imsg *imsg)
{
        struct iked     *env = iked_env;
        struct ca_store *store = env->sc_priv;

        switch (imsg->hdr.type) {
        case IMSG_CTL_SHOW_CERTSTORE:
                ca_store_info(env, imsg, "CA", store->ca_cas);
                ca_store_info(env, imsg, "CERT", store->ca_certs);
                /* Send empty reply to indicate end of information. */
                proc_compose_imsg(&env->sc_ps, PROC_CONTROL, -1,
                    IMSG_CTL_SHOW_CERTSTORE, imsg->hdr.peerid,
                    -1, NULL, 0);
                break;
        default:
                return (-1);
        }

        return (0);
}

int
ca_setcert(struct iked *env, struct iked_sahdr *sh, struct iked_id *id,
    uint8_t type, uint8_t *data, size_t len, enum privsep_procid procid)
{
        struct iovec            iov[4];
        int                     iovcnt = 0;
        struct iked_static_id   idb;

        /* Must send the cert and a valid Id to the ca process */
        if (procid == PROC_CERT) {
                if (id == NULL || id->id_type == IKEV2_ID_NONE ||
                    ibuf_size(id->id_buf) > IKED_ID_SIZE)
                        return (-1);
                bzero(&idb, sizeof(idb));

                /* Convert to a static Id */
                idb.id_type = id->id_type;
                idb.id_offset = id->id_offset;
                idb.id_length = ibuf_size(id->id_buf);
                memcpy(&idb.id_data, ibuf_data(id->id_buf),
                    ibuf_size(id->id_buf));

                iov[iovcnt].iov_base = &idb;
                iov[iovcnt].iov_len = sizeof(idb);
                iovcnt++;
        }

        iov[iovcnt].iov_base = sh;
        iov[iovcnt].iov_len = sizeof(*sh);
        iovcnt++;
        iov[iovcnt].iov_base = &type;
        iov[iovcnt].iov_len = sizeof(type);
        iovcnt++;
        if (data != NULL) {
                iov[iovcnt].iov_base = data;
                iov[iovcnt].iov_len = len;
                iovcnt++;
        }

        if (proc_composev(&env->sc_ps, procid, IMSG_CERT, iov, iovcnt) == -1)
                return (-1);
        return (0);
}

static int
ca_setscert(struct iked *env, struct iked_sahdr *sh, uint8_t type, X509 *cert)
{
        struct iovec            iov[3];
        int                     iovcnt = 0;
        struct ibuf             *buf;
        int                     ret;

        if ((buf = ca_x509_serialize(cert)) == NULL)
                return (-1);

        iov[iovcnt].iov_base = sh;
        iov[iovcnt].iov_len = sizeof(*sh);
        iovcnt++;
        iov[iovcnt].iov_base = &type;
        iov[iovcnt].iov_len = sizeof(type);
        iovcnt++;
        iov[iovcnt].iov_base = ibuf_data(buf);
        iov[iovcnt].iov_len = ibuf_size(buf);
        iovcnt++;

        ret = proc_composev(&env->sc_ps, PROC_IKEV2, IMSG_SCERT, iov, iovcnt);
        ibuf_free(buf);
        return (ret);
}

int
ca_setreq(struct iked *env, struct iked_sa *sa,
    struct iked_static_id *localid, uint8_t type, uint8_t more, uint8_t *data,
    size_t len, enum privsep_procid procid)
{
        struct iovec            iov[5];
        int                     iovcnt = 0;
        struct iked_static_id   idb;
        struct iked_id          id;
        int                     ret = -1;

        /* Convert to a static Id */
        bzero(&id, sizeof(id));
        if (ikev2_policy2id(localid, &id, 1) != 0)
                return (-1);

        if (ibuf_size(id.id_buf) > IKED_ID_SIZE)
                return (-1);
        bzero(&idb, sizeof(idb));
        idb.id_type = id.id_type;
        idb.id_offset = id.id_offset;
        idb.id_length = ibuf_size(id.id_buf);
        memcpy(&idb.id_data, ibuf_data(id.id_buf), ibuf_size(id.id_buf));
        iov[iovcnt].iov_base = &idb;
        iov[iovcnt].iov_len = sizeof(idb);
        iovcnt++;

        iov[iovcnt].iov_base = &sa->sa_hdr;
        iov[iovcnt].iov_len = sizeof(sa->sa_hdr);
        iovcnt++;
        iov[iovcnt].iov_base = &type;
        iov[iovcnt].iov_len = sizeof(type);
        iovcnt++;
        iov[iovcnt].iov_base = &more;
        iov[iovcnt].iov_len = sizeof(more);
        iovcnt++;
        if (data != NULL) {
                iov[iovcnt].iov_base = data;
                iov[iovcnt].iov_len = len;
                iovcnt++;
        }

        if (proc_composev(&env->sc_ps, procid, IMSG_CERTREQ, iov, iovcnt) == -1)
                goto done;

        sa_stateflags(sa, IKED_REQ_CERTREQ);

        ret = 0;
 done:
        ibuf_free(id.id_buf);
        return (ret);
}

static int
auth_sig_compatible(uint8_t type)
{
        switch (type) {
        case IKEV2_AUTH_RSA_SIG:
        case IKEV2_AUTH_ECDSA_256:
        case IKEV2_AUTH_ECDSA_384:
        case IKEV2_AUTH_ECDSA_521:
        case IKEV2_AUTH_SIG_ANY:
                return (1);
        }
        return (0);
}

int
ca_setauth(struct iked *env, struct iked_sa *sa,
    struct ibuf *authmsg, enum privsep_procid id)
{
        struct iovec             iov[3];
        int                      iovcnt = 3;
        struct iked_policy      *policy = sa->sa_policy;
        uint8_t                  type = policy->pol_auth.auth_method;

        if (id == PROC_CERT) {
                /* switch encoding to IKEV2_AUTH_SIG if SHA2 is supported */
                if (sa->sa_sigsha2 && auth_sig_compatible(type)) {
                        log_debug("%s: switching %s to SIG", __func__,
                            print_map(type, ikev2_auth_map));
                        type = IKEV2_AUTH_SIG;
                } else if (!sa->sa_sigsha2 && type == IKEV2_AUTH_SIG_ANY) {
                        log_debug("%s: switching SIG to RSA_SIG(*)", __func__);
                        /* XXX ca might auto-switch to ECDSA */
                        type = IKEV2_AUTH_RSA_SIG;
                } else if (type == IKEV2_AUTH_SIG) {
                        log_debug("%s: using SIG (RFC7427)", __func__);
                }
        }

        if (type == IKEV2_AUTH_SHARED_KEY_MIC) {
                sa->sa_stateflags |= IKED_REQ_AUTH;
                return (ikev2_msg_authsign(env, sa,
                    &policy->pol_auth, authmsg));
        }

        iov[0].iov_base = &sa->sa_hdr;
        iov[0].iov_len = sizeof(sa->sa_hdr);
        iov[1].iov_base = &type;
        iov[1].iov_len = sizeof(type);
        if (type == IKEV2_AUTH_NONE)
                iovcnt--;
        else {
                iov[2].iov_base = ibuf_data(authmsg);
                iov[2].iov_len = ibuf_size(authmsg);
                log_debug("%s: auth length %zu", __func__, ibuf_size(authmsg));
        }

        if (proc_composev(&env->sc_ps, id, IMSG_AUTH, iov, iovcnt) == -1)
                return (-1);
        return (0);
}

int
ca_getcert(struct iked *env, struct imsg *imsg)
{
        struct ca_store         *store = env->sc_priv;
        X509                    *issuer = NULL, *cert;
        STACK_OF(X509)          *untrusted = NULL;
        EVP_PKEY                *certkey;
        struct iked_sahdr        sh;
        uint8_t                  type;
        uint8_t                 *ptr;
        size_t                   len;
        struct iked_static_id    id;
        unsigned int             i;
        struct iovec             iov[3];
        int                      iovcnt = 3, cmd, ret = 0;
        struct iked_id           key;

        ptr = (uint8_t *)imsg->data;
        len = IMSG_DATA_SIZE(imsg);
        i = sizeof(id) + sizeof(sh) + sizeof(type);
        if (len < i)
                return (-1);

        memcpy(&id, ptr, sizeof(id));
        if (id.id_type == IKEV2_ID_NONE)
                return (-1);
        memcpy(&sh, ptr + sizeof(id), sizeof(sh));
        memcpy(&type, ptr + sizeof(id) + sizeof(sh), sizeof(uint8_t));

        ptr += i;
        len -= i;

        bzero(&key, sizeof(key));

        if (type == IKEV2_CERT_BUNDLE &&
            ca_decode_cert_bundle(env, &sh, &ptr, &len, &untrusted) == 0)
                type = IKEV2_CERT_X509_CERT;

        switch (type) {
        case IKEV2_CERT_X509_CERT:
                /* Look in local cert storage first */
                cert = ca_by_subjectaltname(store->ca_certs, &id);
                if (cert) {
                        log_debug("%s: found local cert", __func__);
                        if ((certkey = X509_get0_pubkey(cert)) != NULL) {
                                ret = ca_pubkey_serialize(certkey, &key);
                                if (ret == 0) {
                                        ptr = ibuf_data(key.id_buf);
                                        len = ibuf_size(key.id_buf);
                                        type = key.id_type;
                                        break;
                                }
                        }
                }
                if (env->sc_ocsp_url == NULL)
                        ret = ca_validate_cert(env, &id, ptr, len, untrusted, NULL);
                else {
                        ret = ca_validate_cert(env, &id, ptr, len, untrusted, &issuer);
                        if (ret == 0) {
                                ret = ocsp_validate_cert(env, ptr, len, sh,
                                    type, issuer);
                                X509_free(issuer);
                                if (ret == 0) {
                                        sk_X509_pop_free(untrusted, X509_free);
                                        return (0);
                                }
                        } else
                                X509_free(issuer);
                }
                break;
        case IKEV2_CERT_RSA_KEY:
        case IKEV2_CERT_ECDSA:
                ret = ca_validate_pubkey(env, &id, ptr, len, NULL);
                break;
        case IKEV2_CERT_NONE:
                /* Fallback to public key */
                ret = ca_validate_pubkey(env, &id, NULL, 0, &key);
                if (ret == 0) {
                        ptr = ibuf_data(key.id_buf);
                        len = ibuf_size(key.id_buf);
                        type = key.id_type;
                }
                break;
        default:
                log_debug("%s: unsupported cert type %d", __func__, type);
                ret = -1;
                break;
        }

        if (ret == 0)
                cmd = IMSG_CERTVALID;
        else
                cmd = IMSG_CERTINVALID;

        iov[0].iov_base = &sh;
        iov[0].iov_len = sizeof(sh);
        iov[1].iov_base = &type;
        iov[1].iov_len = sizeof(type);
        iov[2].iov_base = ptr;
        iov[2].iov_len = len;

        ret = proc_composev(&env->sc_ps, PROC_IKEV2, cmd, iov, iovcnt);
        ibuf_free(key.id_buf);
        sk_X509_pop_free(untrusted, X509_free);

        return (ret);
}

static unsigned int
ca_chain_by_issuer(struct ca_store *store, X509_NAME *subject,
    struct iked_static_id *id, X509 **dst, size_t dstlen)
{
        STACK_OF(X509_OBJECT)   *h;
        X509_OBJECT             *xo;
        X509                    *cert;
        int                     i;
        unsigned int            n;
        X509_NAME               *issuer, *subj;

        if (subject == NULL || dstlen == 0)
                return (0);

        if ((cert = ca_by_issuer(store->ca_certs, subject, id)) != NULL) {
                *dst = cert;
                return (1);
        }

        h = X509_STORE_get0_objects(store->ca_cas);
        for (i = 0; i < sk_X509_OBJECT_num(h); i++) {
                xo = sk_X509_OBJECT_value(h, i);
                if (X509_OBJECT_get_type(xo) != X509_LU_X509)
                        continue;
                cert = X509_OBJECT_get0_X509(xo);
                if ((issuer = X509_get_issuer_name(cert)) == NULL)
                        continue;
                if (X509_NAME_cmp(subject, issuer) == 0) {
                        if ((subj = X509_get_subject_name(cert)) == NULL)
                                continue;
                        /* Skip root CAs */
                        if (X509_NAME_cmp(subj, issuer) == 0)
                                continue;
                        n = ca_chain_by_issuer(store, subj, id,
                            dst + 1, dstlen - 1);
                        if (n > 0) {
                                *dst = cert;
                                return (n + 1);
                        }
                }
        }

        return (0);
}

int
ca_getreq(struct iked *env, struct imsg *imsg)
{
        struct ca_store         *store = env->sc_priv;
        struct iked_sahdr        sh;
        uint8_t                  type, more;
        uint8_t                 *ptr;
        size_t                   len;
        unsigned int             i;
        X509                    *ca = NULL, *cert = NULL;
        X509                    *chain[IKED_SCERT_MAX + 1];
        size_t                   chain_len = 0;
        struct ibuf             *buf;
        struct iked_static_id    id;
        char                     idstr[IKED_ID_SIZE];
        X509_NAME               *subj;
        char                    *subj_name;

        ptr = (uint8_t *)imsg->data;
        len = IMSG_DATA_SIZE(imsg);
        i = sizeof(id) + sizeof(type) + sizeof(sh) + sizeof(more);
        if (len < i)
                return (-1);

        memcpy(&id, ptr, sizeof(id));
        if (id.id_type == IKEV2_ID_NONE)
                return (-1);
        memcpy(&sh, ptr + sizeof(id), sizeof(sh));
        memcpy(&type, ptr + sizeof(id) + sizeof(sh), sizeof(type));
        memcpy(&more, ptr + sizeof(id) + sizeof(sh) + sizeof(type), sizeof(more));

        ptr += i;
        len -= i;

        switch (type) {
        case IKEV2_CERT_RSA_KEY:
        case IKEV2_CERT_ECDSA:
                /*
                 * Find a local raw public key that matches the type
                 * received in the CERTREQ payoad
                 */
                if (store->ca_pubkey.id_type != type ||
                    store->ca_pubkey.id_buf == NULL)
                        goto fallback;

                buf = ibuf_dup(store->ca_pubkey.id_buf);
                log_debug("%s: using local public key of type %s", __func__,
                    print_map(type, ikev2_cert_map));
                break;
        case IKEV2_CERT_X509_CERT:
                if (len == 0 || len % SHA_DIGEST_LENGTH) {
                        log_info("%s: invalid CERTREQ data.",
                            SPI_SH(&sh, __func__));
                        return (-1);
                }

                /*
                 * Find a local certificate signed by any of the CAs
                 * received in the CERTREQ payload
                 */
                for (i = 0; i < len; i += SHA_DIGEST_LENGTH) {
                        if ((ca = ca_by_subjectpubkey(store->ca_cas, ptr + i,
                            SHA_DIGEST_LENGTH)) == NULL)
                                continue;
                        subj = X509_get_subject_name(ca);
                        if (subj == NULL)
                                return (-1);
                        subj_name = X509_NAME_oneline(subj, NULL, 0);
                        if (subj_name == NULL)
                                return (-1);
                        log_debug("%s: found CA %s", __func__, subj_name);
                        OPENSSL_free(subj_name);

                        chain_len = ca_chain_by_issuer(store, subj, &id,
                            chain, nitems(chain));
                        if (chain_len > 0) {
                                cert = chain[chain_len - 1];
                                if (!ca_cert_local(env, cert)) {
                                        log_info("%s: found cert with matching "
                                            "ID but without matching key.",
                                            SPI_SH(&sh, __func__));
                                        continue;
                                }
                                break;
                        }
                }

                for (i = chain_len; i >= 2; i--)
                        ca_setscert(env, &sh, type, chain[i - 2]);

                /* Fallthrough */
        case IKEV2_CERT_NONE:
 fallback:
                /*
                 * If no certificate or key matching any of the trust-anchors
                 * was found and this was the last CERTREQ, try to find one with
                 * subjectAltName matching the ID
                 */
                if (cert == NULL && more)
                        return (0);

                if (cert == NULL)
                        cert = ca_by_subjectaltname(store->ca_certs, &id);

                /* Set type if coming from fallback */
                if (cert != NULL)
                        type = IKEV2_CERT_X509_CERT;

                /* If there is no matching certificate use local raw pubkey */
                if (cert == NULL) {
                        if (ikev2_print_static_id(&id, idstr, sizeof(idstr)) == -1)
                                return (-1);
                        log_info("%s: no valid local certificate found for %s",
                            SPI_SH(&sh, __func__), idstr);
                        ca_store_certs_info(SPI_SH(&sh, __func__),
                            store->ca_certs);
                        if (store->ca_pubkey.id_buf == NULL)
                                return (-1);
                        buf = ibuf_dup(store->ca_pubkey.id_buf);
                        type = store->ca_pubkey.id_type;
                        log_info("%s: using local public key of type %s",
                            SPI_SH(&sh, __func__),
                            print_map(type, ikev2_cert_map));
                        break;
                }

                subj = X509_get_subject_name(cert);
                if (subj == NULL)
                        return (-1);
                subj_name = X509_NAME_oneline(subj, NULL, 0);
                if (subj_name == NULL)
                        return (-1);
                log_debug("%s: found local certificate %s", __func__,
                    subj_name);
                OPENSSL_free(subj_name);

                if ((buf = ca_x509_serialize(cert)) == NULL)
                        return (-1);
                break;
        default:
                log_warnx("%s: unknown cert type requested",
                    SPI_SH(&sh, __func__));
                return (-1);
        }

        ca_setcert(env, &sh, NULL, type,
            ibuf_data(buf), ibuf_size(buf), PROC_IKEV2);
        ibuf_free(buf);

        return (0);
}

int
ca_getauth(struct iked *env, struct imsg *imsg)
{
        struct ca_store         *store = env->sc_priv;
        struct iked_sahdr        sh;
        uint8_t                  method;
        uint8_t                 *ptr;
        size_t                   len;
        unsigned int             i;
        int                      ret = -1;
        struct iked_sa           sa;
        struct iked_policy       policy;
        struct iked_id          *id;
        struct ibuf             *authmsg;

        ptr = (uint8_t *)imsg->data;
        len = IMSG_DATA_SIZE(imsg);
        i = sizeof(method) + sizeof(sh);
        if (len <= i)
                return (-1);

        memcpy(&sh, ptr, sizeof(sh));
        memcpy(&method, ptr + sizeof(sh), sizeof(uint8_t));
        if (method == IKEV2_AUTH_SHARED_KEY_MIC)
                return (-1);

        ptr += i;
        len -= i;

        if ((authmsg = ibuf_new(ptr, len)) == NULL)
                return (-1);

        /*
         * Create fake SA and policy
         */
        bzero(&sa, sizeof(sa));
        bzero(&policy, sizeof(policy));
        memcpy(&sa.sa_hdr, &sh, sizeof(sh));
        sa.sa_policy = &policy;
        if (sh.sh_initiator)
                id = &sa.sa_icert;
        else
                id = &sa.sa_rcert;
        memcpy(id, &store->ca_privkey, sizeof(*id));
        policy.pol_auth.auth_method = method == IKEV2_AUTH_SIG ?
            method : store->ca_privkey_method;

        if (ikev2_msg_authsign(env, &sa, &policy.pol_auth, authmsg) != 0) {
                log_debug("%s: AUTH sign failed", __func__);
                policy.pol_auth.auth_method = IKEV2_AUTH_NONE;
        }

        ret = ca_setauth(env, &sa, sa.sa_localauth.id_buf, PROC_IKEV2);

        ibuf_free(sa.sa_localauth.id_buf);
        sa.sa_localauth.id_buf = NULL;
        ibuf_free(authmsg);

        return (ret);
}

int
ca_reload(struct iked *env)
{
        struct ca_store         *store = env->sc_priv;
        uint8_t                  md[EVP_MAX_MD_SIZE];
        char                     file[PATH_MAX];
        struct iovec             iov[2];
        struct dirent           *entry;
        STACK_OF(X509_OBJECT)   *h;
        X509_OBJECT             *xo;
        X509                    *x509;
        DIR                     *dir;
        int                      i, iovcnt = 0;
        unsigned int             len;
        X509_NAME               *subj;
        char                    *subj_name;

        /*
         * Load CAs
         */
        if ((dir = opendir(IKED_CA_DIR)) == NULL)
                return (-1);

        while ((entry = readdir(dir)) != NULL) {
                if ((entry->d_type != DT_REG) &&
                    (entry->d_type != DT_LNK))
                        continue;

                if (snprintf(file, sizeof(file), "%s%s",
                    IKED_CA_DIR, entry->d_name) < 0)
                        continue;

                if (!X509_load_cert_file(store->ca_calookup, file,
                    X509_FILETYPE_PEM)) {
                        log_warn("%s: failed to load ca file %s", __func__,
                            entry->d_name);
                        ca_sslerror(__func__);
                        continue;
                }
                log_debug("%s: loaded ca file %s", __func__, entry->d_name);
        }
        closedir(dir);

        /*
         * Load CRLs for the CAs
         */
        if ((dir = opendir(IKED_CRL_DIR)) == NULL)
                return (-1);

        while ((entry = readdir(dir)) != NULL) {
                if ((entry->d_type != DT_REG) &&
                    (entry->d_type != DT_LNK))
                        continue;

                if (snprintf(file, sizeof(file), "%s%s",
                    IKED_CRL_DIR, entry->d_name) < 0)
                        continue;

                if (!X509_load_crl_file(store->ca_calookup, file,
                    X509_FILETYPE_PEM)) {
                        log_warn("%s: failed to load crl file %s", __func__,
                            entry->d_name);
                        ca_sslerror(__func__);
                        continue;
                }

                /* Only enable CRL checks if we actually loaded a CRL */
                X509_STORE_set_flags(store->ca_cas, X509_V_FLAG_CRL_CHECK);

                log_debug("%s: loaded crl file %s", __func__, entry->d_name);
        }
        closedir(dir);

        /*
         * Load certificates
         */
        if ((dir = opendir(IKED_CERT_DIR)) == NULL)
                return (-1);

        while ((entry = readdir(dir)) != NULL) {
                if ((entry->d_type != DT_REG) &&
                    (entry->d_type != DT_LNK))
                        continue;

                if (snprintf(file, sizeof(file), "%s%s",
                    IKED_CERT_DIR, entry->d_name) < 0)
                        continue;

                if (!ca_load_cert_file(store, file)) {
                        log_warn("%s: failed to load cert file %s", __func__,
                            entry->d_name);
                        ca_sslerror(__func__);
                        continue;
                }
                log_debug("%s: loaded cert file %s", __func__, entry->d_name);
        }
        closedir(dir);

        /*
         * Save CAs signatures for the IKEv2 CERTREQ
         */
        ibuf_free(env->sc_certreq);
        if ((env->sc_certreq = ibuf_new(NULL, 0)) == NULL)
                return (-1);

        h = X509_STORE_get0_objects(store->ca_cas);
        for (i = 0; i < sk_X509_OBJECT_num(h); i++) {
                xo = sk_X509_OBJECT_value(h, i);
                if (X509_OBJECT_get_type(xo) != X509_LU_X509)
                        continue;

                x509 = X509_OBJECT_get0_X509(xo);
                len = sizeof(md);
                ca_subjectpubkey_digest(x509, md, &len);
                subj = X509_get_subject_name(x509);
                if (subj == NULL)
                        return (-1);
                subj_name = X509_NAME_oneline(subj, NULL, 0);
                if (subj_name == NULL)
                        return (-1);
                log_debug("%s: %s", __func__, subj_name);
                OPENSSL_free(subj_name);

                if (ibuf_add(env->sc_certreq, md, len) != 0) {
                        ibuf_free(env->sc_certreq);
                        env->sc_certreq = NULL;
                        return (-1);
                }
        }

        if (ibuf_size(env->sc_certreq)) {
                env->sc_certreqtype = IKEV2_CERT_X509_CERT;
                iov[0].iov_base = &env->sc_certreqtype;
                iov[0].iov_len = sizeof(env->sc_certreqtype);
                iovcnt++;
                iov[1].iov_base = ibuf_data(env->sc_certreq);
                iov[1].iov_len = ibuf_size(env->sc_certreq);
                iovcnt++;

                log_debug("%s: loaded %zu ca certificate%s", __func__,
                    ibuf_size(env->sc_certreq) / SHA_DIGEST_LENGTH,
                    ibuf_size(env->sc_certreq) == SHA_DIGEST_LENGTH ?
                    "" : "s");

                (void)proc_composev(&env->sc_ps, PROC_IKEV2, IMSG_CERTREQ,
                    iov, iovcnt);
        }

        h = X509_STORE_get0_objects(store->ca_certs);
        for (i = 0; i < sk_X509_OBJECT_num(h); i++) {
                xo = sk_X509_OBJECT_value(h, i);
                if (X509_OBJECT_get_type(xo) != X509_LU_X509)
                        continue;

                x509 = X509_OBJECT_get0_X509(xo);

                (void)ca_validate_cert(env, NULL, x509, 0, NULL, NULL);
        }

        if (!env->sc_certreqtype)
                env->sc_certreqtype = store->ca_pubkey.id_type;

        log_debug("%s: local cert type %s", __func__,
            print_map(env->sc_certreqtype, ikev2_cert_map));

        iov[0].iov_base = &env->sc_certreqtype;
        iov[0].iov_len = sizeof(env->sc_certreqtype);
        if (iovcnt == 0)
                iovcnt++;
        (void)proc_composev(&env->sc_ps, PROC_IKEV2, IMSG_CERTREQ, iov, iovcnt);

        return (0);
}

int
ca_load_cert_file(struct ca_store *store, char *file)
{
        int      ret = 0, i, count = 0;
        BIO     *in = NULL;
        X509    *x = NULL;

        in = BIO_new(BIO_s_file());

        if ((in == NULL) || (BIO_read_filename(in, file) <= 0))
                goto done;

        if ((x = PEM_read_bio_X509_AUX(in, NULL, NULL, "")) == NULL)
                goto done;
        if ((i = X509_STORE_add_cert(store->ca_certs, x)) == 0)
                goto done;
        count++;
        X509_free(x);
        x = NULL;

        while ((x = PEM_read_bio_X509_AUX(in, NULL, NULL, "")) != NULL) {
                i = X509_STORE_add_cert(store->ca_cas, x);
                if (i == 0)
                        goto done;
                count++;
                X509_free(x);
                x = NULL;
        }
        ret = count;
done:
        X509_free(x);
        BIO_free(in);

        return (ret);
}

X509 *
ca_by_subjectpubkey(X509_STORE *ctx, uint8_t *sig, size_t siglen)
{
        STACK_OF(X509_OBJECT)   *h;
        X509_OBJECT             *xo;
        X509                    *ca;
        int                      i;
        unsigned int             len;
        uint8_t                  md[EVP_MAX_MD_SIZE];

        h = X509_STORE_get0_objects(ctx);

        for (i = 0; i < sk_X509_OBJECT_num(h); i++) {
                xo = sk_X509_OBJECT_value(h, i);
                if (X509_OBJECT_get_type(xo) != X509_LU_X509)
                        continue;

                ca = X509_OBJECT_get0_X509(xo);
                len = sizeof(md);
                ca_subjectpubkey_digest(ca, md, &len);

                if (len == siglen && memcmp(md, sig, len) == 0)
                        return (ca);
        }

        return (NULL);
}

X509 *
ca_by_issuer(X509_STORE *ctx, X509_NAME *subject, struct iked_static_id *id)
{
        STACK_OF(X509_OBJECT)   *h;
        X509_OBJECT             *xo;
        X509                    *cert;
        int                      i;
        X509_NAME               *issuer;

        if (subject == NULL)
                return (NULL);

        h = X509_STORE_get0_objects(ctx);
        for (i = 0; i < sk_X509_OBJECT_num(h); i++) {
                xo = sk_X509_OBJECT_value(h, i);
                if (X509_OBJECT_get_type(xo) != X509_LU_X509)
                        continue;

                cert = X509_OBJECT_get0_X509(xo);
                if ((issuer = X509_get_issuer_name(cert)) == NULL)
                        continue;
                else if (X509_NAME_cmp(subject, issuer) == 0) {
                        switch (id->id_type) {
                        case IKEV2_ID_ASN1_DN:
                                if (ca_x509_subject_cmp(cert, id) == 0)
                                        return (cert);
                                break;
                        default:
                                if (ca_x509_subjectaltname_cmp(cert, id) == 0)
                                        return (cert);
                                break;
                        }
                }
        }

        return (NULL);
}

X509 *
ca_by_subjectaltname(X509_STORE *ctx, struct iked_static_id *id)
{
        STACK_OF(X509_OBJECT)   *h;
        X509_OBJECT             *xo;
        X509                    *cert;
        int                      i;

        h = X509_STORE_get0_objects(ctx);
        for (i = 0; i < sk_X509_OBJECT_num(h); i++) {
                xo = sk_X509_OBJECT_value(h, i);
                if (X509_OBJECT_get_type(xo) != X509_LU_X509)
                        continue;

                cert = X509_OBJECT_get0_X509(xo);
                switch (id->id_type) {
                case IKEV2_ID_ASN1_DN:
                        if (ca_x509_subject_cmp(cert, id) == 0)
                                return (cert);
                        break;
                default:
                        if (ca_x509_subjectaltname_cmp(cert, id) == 0)
                                return (cert);
                        break;
                }
        }

        return (NULL);
}

void
ca_store_certs_info(const char *msg, X509_STORE *ctx)
{
        STACK_OF(X509_OBJECT)   *h;
        X509_OBJECT             *xo;
        X509                    *cert;
        int                      i;

        h = X509_STORE_get0_objects(ctx);
        for (i = 0; i < sk_X509_OBJECT_num(h); i++) {
                xo = sk_X509_OBJECT_value(h, i);
                if (X509_OBJECT_get_type(xo) != X509_LU_X509)
                        continue;
                cert = X509_OBJECT_get0_X509(xo);
                ca_cert_info(msg, cert);
        }
}

int
ca_cert_local(struct iked *env, X509  *cert)
{
        struct ca_store *store = env->sc_priv;
        EVP_PKEY        *certkey = NULL, *localpub = NULL;
        int              ret = 0;

        if ((localpub = ca_bytes_to_pkey(ibuf_data(store->ca_pubkey.id_buf),
            ibuf_size(store->ca_pubkey.id_buf))) == NULL)
                goto done;

        if ((certkey = X509_get0_pubkey(cert)) == NULL) {
                log_info("%s: no public key in cert", __func__);
                goto done;
        }

        if (EVP_PKEY_cmp(certkey, localpub) != 1) {
                log_debug("%s: certificate key mismatch", __func__);
                goto done;
        }

        ret = 1;
 done:
        EVP_PKEY_free(localpub);

        return (ret);
}

void
ca_cert_info(const char *msg, X509 *cert)
{
        ASN1_INTEGER    *asn1_serial;
        BUF_MEM         *memptr;
        BIO             *rawserial = NULL;
        char             buf[BUFSIZ];
        X509_NAME       *name;

        if ((asn1_serial = X509_get_serialNumber(cert)) == NULL ||
            (rawserial = BIO_new(BIO_s_mem())) == NULL ||
            i2a_ASN1_INTEGER(rawserial, asn1_serial) <= 0)
                goto out;

        name = X509_get_issuer_name(cert);
        if (name != NULL &&
            X509_NAME_oneline(name, buf, sizeof(buf)))
                log_info("%s: issuer: %s", msg, buf);
        BIO_get_mem_ptr(rawserial, &memptr);
        if (memptr->data != NULL && memptr->length < INT32_MAX)
                log_info("%s: serial: %.*s", msg, (int)memptr->length,
                    memptr->data);
        name = X509_get_subject_name(cert);
        if (name != NULL &&
            X509_NAME_oneline(name, buf, sizeof(buf)))
                log_info("%s: subject: %s", msg, buf);
        ca_x509_subjectaltname_log(cert, msg);
out:
        BIO_free(rawserial);
}

int
ca_subjectpubkey_digest(X509 *x509, uint8_t *md, unsigned int *size)
{
        EVP_PKEY        *pkey;
        uint8_t         *buf = NULL;
        int              buflen;

        if (*size < SHA_DIGEST_LENGTH)
                return (-1);

        /*
         * Generate a SHA-1 digest of the Subject Public Key Info
         * element in the X.509 certificate, an ASN.1 sequence
         * that includes the public key type (eg. RSA) and the
         * public key value (see 3.7 of RFC7296).
         */
        if ((pkey = X509_get0_pubkey(x509)) == NULL)
                return (-1);
        buflen = i2d_PUBKEY(pkey, &buf);
        if (buflen == 0)
                return (-1);
        if (!EVP_Digest(buf, buflen, md, size, EVP_sha1(), NULL)) {
                OPENSSL_free(buf);
                return (-1);
        }
        OPENSSL_free(buf);

        return (0);
}

void
ca_store_info(struct iked *env, struct imsg *imsg, const char *msg, X509_STORE *ctx)
{
        STACK_OF(X509_OBJECT)   *h;
        X509_OBJECT             *xo;
        X509                    *cert;
        int                      i;
        X509_NAME               *subject;
        char                    *name;
        char                    *buf;
        int                      buflen;

        h = X509_STORE_get0_objects(ctx);
        for (i = 0; i < sk_X509_OBJECT_num(h); i++) {
                xo = sk_X509_OBJECT_value(h, i);
                if (X509_OBJECT_get_type(xo) != X509_LU_X509)
                        continue;
                cert = X509_OBJECT_get0_X509(xo);
                if ((subject = X509_get_subject_name(cert)) == NULL ||
                    (name = X509_NAME_oneline(subject, NULL, 0)) == NULL)
                        continue;
                buflen = asprintf(&buf, "%s: %s\n", msg, name);
                OPENSSL_free(name);
                if (buflen == -1)
                        continue;
                proc_compose_imsg(&env->sc_ps, PROC_CONTROL, -1,
                    IMSG_CTL_SHOW_CERTSTORE, imsg->hdr.peerid,
                    -1, buf, buflen + 1);
                free(buf);
        }
}

struct ibuf *
ca_x509_serialize(X509 *x509)
{
        long             len;
        struct ibuf     *buf;
        uint8_t         *d = NULL;
        BIO             *out;

        if ((out = BIO_new(BIO_s_mem())) == NULL)
                return (NULL);
        if (!i2d_X509_bio(out, x509)) {
                BIO_free(out);
                return (NULL);
        }

        len = BIO_get_mem_data(out, &d);
        buf = ibuf_new(d, len);
        BIO_free(out);

        return (buf);
}

int
ca_pubkey_serialize(EVP_PKEY *key, struct iked_id *id)
{
        RSA             *rsa = NULL;
        EC_KEY          *ec = NULL;
        uint8_t         *d;
        int              len = 0;
        int              ret = -1;

        switch (EVP_PKEY_id(key)) {
        case EVP_PKEY_RSA:
                id->id_type = 0;
                id->id_offset = 0;
                ibuf_free(id->id_buf);
                id->id_buf = NULL;

                if ((rsa = EVP_PKEY_get0_RSA(key)) == NULL)
                        goto done;
                if ((len = i2d_RSAPublicKey(rsa, NULL)) <= 0)
                        goto done;
                if ((id->id_buf = ibuf_new(NULL, len)) == NULL)
                        goto done;

                d = ibuf_data(id->id_buf);
                if (i2d_RSAPublicKey(rsa, &d) != len) {
                        ibuf_free(id->id_buf);
                        id->id_buf = NULL;
                        goto done;
                }

                id->id_type = IKEV2_CERT_RSA_KEY;
                break;
        case EVP_PKEY_EC:
                id->id_type = 0;
                id->id_offset = 0;
                ibuf_free(id->id_buf);
                id->id_buf = NULL;

                if ((ec = EVP_PKEY_get0_EC_KEY(key)) == NULL)
                        goto done;
                if ((len = i2d_EC_PUBKEY(ec, NULL)) <= 0)
                        goto done;
                if ((id->id_buf = ibuf_new(NULL, len)) == NULL)
                        goto done;

                d = ibuf_data(id->id_buf);
                if (i2d_EC_PUBKEY(ec, &d) != len) {
                        ibuf_free(id->id_buf);
                        id->id_buf = NULL;
                        goto done;
                }

                id->id_type = IKEV2_CERT_ECDSA;
                break;
        default:
                log_debug("%s: unsupported key type %d", __func__,
                    EVP_PKEY_id(key));
                return (-1);
        }

        log_debug("%s: type %s length %d", __func__,
            print_map(id->id_type, ikev2_cert_map), len);

        ret = 0;
 done:

        return (ret);
}

int
ca_privkey_serialize(EVP_PKEY *key, struct iked_id *id)
{
        RSA             *rsa = NULL;
        EC_KEY          *ec = NULL;
        uint8_t         *d;
        int              len = 0;
        int              ret = -1;

        switch (EVP_PKEY_id(key)) {
        case EVP_PKEY_RSA:
                id->id_type = 0;
                id->id_offset = 0;
                ibuf_free(id->id_buf);
                id->id_buf = NULL;

                if ((rsa = EVP_PKEY_get0_RSA(key)) == NULL)
                        goto done;
                if ((len = i2d_RSAPrivateKey(rsa, NULL)) <= 0)
                        goto done;
                if ((id->id_buf = ibuf_new(NULL, len)) == NULL)
                        goto done;

                d = ibuf_data(id->id_buf);
                if (i2d_RSAPrivateKey(rsa, &d) != len) {
                        ibuf_free(id->id_buf);
                        id->id_buf = NULL;
                        goto done;
                }

                id->id_type = IKEV2_CERT_RSA_KEY;
                break;
        case EVP_PKEY_EC:
                id->id_type = 0;
                id->id_offset = 0;
                ibuf_free(id->id_buf);
                id->id_buf = NULL;

                if ((ec = EVP_PKEY_get0_EC_KEY(key)) == NULL)
                        goto done;
                if ((len = i2d_ECPrivateKey(ec, NULL)) <= 0)
                        goto done;
                if ((id->id_buf = ibuf_new(NULL, len)) == NULL)
                        goto done;

                d = ibuf_data(id->id_buf);
                if (i2d_ECPrivateKey(ec, &d) != len) {
                        ibuf_free(id->id_buf);
                        id->id_buf = NULL;
                        goto done;
                }

                id->id_type = IKEV2_CERT_ECDSA;
                break;
        default:
                log_debug("%s: unsupported key type %d", __func__,
                    EVP_PKEY_id(key));
                return (-1);
        }

        log_debug("%s: type %s length %d", __func__,
            print_map(id->id_type, ikev2_cert_map), len);

        ret = 0;
 done:

        return (ret);
}

EVP_PKEY *
ca_bytes_to_pkey(uint8_t *data, size_t len)
{
        BIO             *rawcert = NULL;
        EVP_PKEY        *localkey = NULL, *out = NULL;
        RSA             *localrsa = NULL;
        EC_KEY          *localec = NULL;

        if ((rawcert = BIO_new_mem_buf(data, len)) == NULL)
                goto done;

        if ((localkey = EVP_PKEY_new()) == NULL)
                goto sslerr;

        if ((localrsa = d2i_RSAPublicKey_bio(rawcert, NULL))) {
                if (EVP_PKEY_set1_RSA(localkey, localrsa) != 1)
                        goto sslerr;
        } else if (BIO_reset(rawcert) == 1 &&
            (localec = d2i_EC_PUBKEY_bio(rawcert, NULL))) {
                if (EVP_PKEY_set1_EC_KEY(localkey, localec) != 1)
                        goto sslerr;
        } else {
                log_info("%s: unknown public key type", __func__);
                goto done;
        }

        out = localkey;
        localkey = NULL;

 sslerr:
        if (out == NULL)
                ca_sslerror(__func__);
 done:
        EVP_PKEY_free(localkey);
        RSA_free(localrsa);
        EC_KEY_free(localec);
        BIO_free(rawcert);

        return (out);
}

int
ca_privkey_to_method(struct iked_id *privkey)
{
        BIO             *rawcert = NULL;
        EC_KEY          *ec = NULL;
        const EC_GROUP  *group = NULL;
        uint8_t  method = IKEV2_AUTH_NONE;

        switch (privkey->id_type) {
        case IKEV2_CERT_RSA_KEY:
                method = IKEV2_AUTH_RSA_SIG;
                break;
        case IKEV2_CERT_ECDSA:
                if ((rawcert = BIO_new_mem_buf(ibuf_data(privkey->id_buf),
                    ibuf_size(privkey->id_buf))) == NULL)
                        goto out;
                if ((ec = d2i_ECPrivateKey_bio(rawcert, NULL)) == NULL)
                        goto out;
                if ((group = EC_KEY_get0_group(ec)) == NULL)
                        goto out;
                switch (EC_GROUP_get_degree(group)) {
                case 256:
                        method = IKEV2_AUTH_ECDSA_256;
                        break;
                case 384:
                        method = IKEV2_AUTH_ECDSA_384;
                        break;
                case 521:
                        method = IKEV2_AUTH_ECDSA_521;
                        break;
                }
        }

        log_debug("%s: type %s method %s", __func__,
            print_map(privkey->id_type, ikev2_cert_map),
            print_map(method, ikev2_auth_map));

 out:
        EC_KEY_free(ec);
        BIO_free(rawcert);
        return (method);
}

/*
 * Return dynamically allocated buffer containing certificate name.
 * The resulting buffer must be freed with OpenSSL_free().
 */
char *
ca_asn1_name(uint8_t *asn1, size_t len)
{
        X509_NAME       *name = NULL;
        char            *str = NULL;
        const uint8_t   *p;

        p = asn1;
        if ((name = d2i_X509_NAME(NULL, &p, len)) == NULL)
                return (NULL);
        str = X509_NAME_oneline(name, NULL, 0);
        X509_NAME_free(name);

        return (str);
}

/*
 * Copy 'src' to 'dst' until 'marker' is found while unescaping '\'
 * characters. The return value tells the caller where to continue
 * parsing (might be the end of the string) or NULL on error.
 */
static char *
ca_x509_name_unescape(char *src, char *dst, char marker)
{
        while (*src) {
                if (*src == marker) {
                        src++;
                        break;
                }
                if (*src == '\\') {
                        src++;
                        if (!*src) {
                                log_warnx("%s: '\\' at end of string",
                                    __func__);
                                *dst = '\0';
                                return (NULL);
                        }
                }
                *dst++ = *src++;
        }
        *dst = '\0';
        return (src);
}
/*
 * Parse an X509 subject name where 'subject' is in the format
 *    /type0=value0/type1=value1/type2=...
 * where characters may be escaped by '\'.
 * See lib/libssl/src/apps/apps.c:parse_name()
 */
void *
ca_x509_name_parse(char *subject)
{
        char            *cp, *value = NULL, *type = NULL;
        size_t           maxlen;
        X509_NAME       *name = NULL;

        if (*subject != '/') {
                log_warnx("%s: leading '/' missing in '%s'", __func__, subject);
                goto err;
        }

        /* length of subject is upper bound for unescaped type/value */
        maxlen = strlen(subject) + 1;

        if ((type = calloc(1, maxlen)) == NULL ||
            (value = calloc(1, maxlen)) == NULL ||
            (name = X509_NAME_new()) == NULL)
                goto err;

        cp = subject + 1;
        while (*cp) {
                /* unescape type, terminated by '=' */
                cp = ca_x509_name_unescape(cp, type, '=');
                if (cp == NULL) {
                        log_warnx("%s: could not parse type", __func__);
                        goto err;
                }
                if (!*cp) {
                        log_warnx("%s: missing value", __func__);
                        goto err;
                }
                /* unescape value, terminated by '/' */
                cp = ca_x509_name_unescape(cp, value, '/');
                if (cp == NULL) {
                        log_warnx("%s: could not parse value", __func__);
                        goto err;
                }
                if (!*type || !*value) {
                        log_warnx("%s: empty type or value", __func__);
                        goto err;
                }
                log_debug("%s: setting '%s' to '%s'", __func__, type, value);
                if (!X509_NAME_add_entry_by_txt(name, type, MBSTRING_ASC,
                    value, -1, -1, 0)) {
                        log_warnx("%s: setting '%s' to '%s' failed", __func__,
                            type, value);
                        ca_sslerror(__func__);
                        goto err;
                }
        }
        free(type);
        free(value);
        return (name);

err:
        X509_NAME_free(name);
        free(type);
        free(value);
        return (NULL);
}

int
ca_validate_pubkey(struct iked *env, struct iked_static_id *id,
    void *data, size_t len, struct iked_id *out)
{
        RSA             *localrsa = NULL;
        EVP_PKEY        *peerkey = NULL, *localkey = NULL;
        int              ret = -1;
        FILE            *fp = NULL;
        char             idstr[IKED_ID_SIZE];
        char             file[PATH_MAX];
        struct iked_id   idp;

        switch (id->id_type) {
        case IKEV2_ID_IPV4:
        case IKEV2_ID_FQDN:
        case IKEV2_ID_UFQDN:
        case IKEV2_ID_IPV6:
                break;
        default:
                /* Some types like ASN1_DN will not be mapped to file names */
                log_debug("%s: unsupported public key type %s",
                    __func__, print_map(id->id_type, ikev2_id_map));
                return (-1);
        }

        bzero(&idp, sizeof(idp));
        if ((idp.id_buf = ibuf_new(id->id_data, id->id_length)) == NULL)
                goto done;

        idp.id_type = id->id_type;
        idp.id_offset = id->id_offset;
        if (ikev2_print_id(&idp, idstr, sizeof(idstr)) == -1)
                goto done;

        if (len == 0 && data) {
                /* Data is already an public key */
                peerkey = (EVP_PKEY *)data;
        }
        if (len > 0) {
                if ((peerkey = ca_bytes_to_pkey(data, len)) == NULL)
                        goto done;
        }

        lc_idtype(idstr);
        if (strlcpy(file, IKED_PUBKEY_DIR, sizeof(file)) >= sizeof(file) ||
            strlcat(file, idstr, sizeof(file)) >= sizeof(file)) {
                log_debug("%s: public key id too long %s", __func__, idstr);
                goto done;
        }

        if ((fp = fopen(file, "r")) == NULL) {
                /* Log to debug when called from ca_validate_cert */
                logit(len == 0 ? LOG_DEBUG : LOG_INFO,
                    "%s: could not open public key %s", __func__, file);
                goto done;
        }
        localkey = PEM_read_PUBKEY(fp, NULL, NULL, NULL);
        if (localkey == NULL) {
                /* reading PKCS #8 failed, try PEM RSA */
                rewind(fp);
                localrsa = PEM_read_RSAPublicKey(fp, NULL, NULL, NULL);
                fclose(fp);
                if (localrsa == NULL)
                        goto sslerr;
                if ((localkey = EVP_PKEY_new()) == NULL)
                        goto sslerr;
                if (!EVP_PKEY_set1_RSA(localkey, localrsa))
                        goto sslerr;
        } else {
                fclose(fp);
        }
        if (localkey == NULL)
                goto sslerr;

        if (peerkey && EVP_PKEY_cmp(peerkey, localkey) != 1) {
                log_debug("%s: public key does not match %s", __func__, file);
                goto done;
        }

        log_debug("%s: valid public key in file %s", __func__, file);

        if (out && ca_pubkey_serialize(localkey, out))
                goto done;

        ret = 0;
 sslerr:
        if (ret != 0)
                ca_sslerror(__func__);
 done:
        ibuf_free(idp.id_buf);
        EVP_PKEY_free(localkey);
        RSA_free(localrsa);
        if (len > 0)
                EVP_PKEY_free(peerkey);

        return (ret);
}

int
ca_validate_cert(struct iked *env, struct iked_static_id *id,
    void *data, size_t len, STACK_OF(X509) *untrusted, X509 **issuerp)
{
        struct ca_store         *store = env->sc_priv;
        X509_STORE_CTX          *csc = NULL;
        X509_VERIFY_PARAM       *param;
        BIO                     *rawcert = NULL;
        X509                    *cert = NULL;
        EVP_PKEY                *pkey;
        int                      ret = -1, result, error;
        const char              *errstr = "failed";
        X509_NAME               *subj;
        char                    *subj_name;
        int                      depth = -1;

        if (issuerp)
                *issuerp = NULL;
        if (len == 0) {
                /* Data is already an X509 certificate */
                cert = (X509 *)data;
        } else {
                /* Convert data to X509 certificate */
                if ((rawcert = BIO_new_mem_buf(data, len)) == NULL)
                        goto done;
                if ((cert = d2i_X509_bio(rawcert, NULL)) == NULL)
                        goto done;
        }

        /* Certificate needs a valid subjectName */
        if (X509_get_subject_name(cert) == NULL) {
                errstr = "invalid subject";
                goto done;
        }

        if (id != NULL) {
                if ((pkey = X509_get0_pubkey(cert)) == NULL) {
                        errstr = "no public key in cert";
                        goto done;
                }
                ret = ca_validate_pubkey(env, id, pkey, 0, NULL);
                if (ret == 0) {
                        errstr = "in public key file, ok";
                        goto done;
                }

                switch (id->id_type) {
                case IKEV2_ID_ASN1_DN:
                        if (ca_x509_subject_cmp(cert, id) < 0) {
                                errstr = "ASN1_DN identifier mismatch";
                                goto done;
                        }
                        break;
                default:
                        if (ca_x509_subjectaltname_cmp(cert, id) != 0) {
                                errstr = "invalid subjectAltName extension";
                                goto done;
                        }
                        break;
                }
        }

        csc = X509_STORE_CTX_new();
        if (csc == NULL) {
                errstr = "failed to alloc csc";
                goto done;
        }
        X509_STORE_CTX_init(csc, store->ca_cas, cert, untrusted);
        param = X509_STORE_get0_param(store->ca_cas);
        if (X509_VERIFY_PARAM_get_flags(param) & X509_V_FLAG_CRL_CHECK) {
                X509_STORE_CTX_set_flags(csc, X509_V_FLAG_CRL_CHECK);
                X509_STORE_CTX_set_flags(csc, X509_V_FLAG_CRL_CHECK_ALL);
        }
        if (env->sc_cert_partial_chain)
                X509_STORE_CTX_set_flags(csc, X509_V_FLAG_PARTIAL_CHAIN);

        result = X509_verify_cert(csc);
        error = X509_STORE_CTX_get_error(csc);
        depth = X509_STORE_CTX_get_error_depth(csc);
        if (error == 0 && issuerp) {
                if (X509_STORE_CTX_get1_issuer(issuerp, csc, cert) != 1) {
                        log_debug("%s: cannot get issuer", __func__);
                        *issuerp = NULL;
                }
        }
        X509_STORE_CTX_cleanup(csc);
        if (error != 0) {
                errstr = X509_verify_cert_error_string(error);
                goto done;
        }

        if (!result) {
                /* XXX should we accept self-signed certificates? */
                errstr = "rejecting self-signed certificate";
                goto done;
        }

        /* Success */
        ret = 0;
        errstr = "ok";

 done:
        if (cert != NULL) {
                subj = X509_get_subject_name(cert);
                if (subj == NULL)
                        goto err;
                subj_name = X509_NAME_oneline(subj, NULL, 0);
                if (subj_name == NULL)
                        goto err;
                log_debug("%s: %s (depth = %d) %.100s", __func__, subj_name,
                    depth, errstr);
                OPENSSL_free(subj_name);
        }
 err:

        if (len > 0)
                X509_free(cert);
        BIO_free(rawcert);
        X509_STORE_CTX_free(csc);

        return (ret);
}

/* check if subject from cert matches the id */
int
ca_x509_subject_cmp(X509 *cert, struct iked_static_id *id)
{
        X509_NAME       *subject, *idname = NULL;
        const uint8_t   *idptr;
        size_t           idlen;
        int              ret = -1;

        if (id->id_type != IKEV2_ID_ASN1_DN)
                return (-1);
        if ((subject = X509_get_subject_name(cert)) == NULL)
                return (-1);
        if (id->id_length <= id->id_offset)
                return (-1);
        idlen = id->id_length - id->id_offset;
        idptr = id->id_data + id->id_offset;
        if ((idname = d2i_X509_NAME(NULL, &idptr, idlen)) == NULL)
                return (-1);
        if (X509_NAME_cmp(subject, idname) == 0)
                ret = 0;
        X509_NAME_free(idname);
        return (ret);
}

#define MODE_ALT_LOG    1
#define MODE_ALT_GET    2
#define MODE_ALT_CMP    3
int
ca_x509_subjectaltname_do(X509 *cert, int mode, const char *logmsg,
    struct iked_static_id *id, struct iked_id *retid)
{
        STACK_OF(GENERAL_NAME) *stack = NULL;
        GENERAL_NAME *entry;
        ASN1_STRING *cstr;
        char idstr[IKED_ID_SIZE];
        int crit, ret, i, type, len;
        const uint8_t *data;

        ret = -1;
        crit = -1;
        if ((stack = X509_get_ext_d2i(cert, NID_subject_alt_name,
            &crit, NULL)) != NULL) {
                for (i = 0; i < sk_GENERAL_NAME_num(stack); i++) {
                        entry = sk_GENERAL_NAME_value(stack, i);
                        switch (entry->type) {
                        case GEN_DNS:
                                cstr = entry->d.dNSName;
                                if (ASN1_STRING_type(cstr) != V_ASN1_IA5STRING)
                                        continue;
                                type = IKEV2_ID_FQDN;
                                break;
                        case GEN_EMAIL:
                                cstr = entry->d.rfc822Name;
                                if (ASN1_STRING_type(cstr) != V_ASN1_IA5STRING)
                                        continue;
                                type = IKEV2_ID_UFQDN;
                                break;
                        case GEN_IPADD:
                                cstr = entry->d.iPAddress;
                                switch (ASN1_STRING_length(cstr)) {
                                case 4:
                                        type = IKEV2_ID_IPV4;
                                        break;
                                case 16:
                                        type = IKEV2_ID_IPV6;
                                        break;
                                default:
                                        log_debug("%s: invalid subjectAltName"
                                           " IP address", __func__);
                                        continue;
                                }
                                break;
                        default:
                                continue;
                        }
                        len = ASN1_STRING_length(cstr);
                        data = ASN1_STRING_get0_data(cstr);
                        if (mode == MODE_ALT_LOG) {
                                struct iked_id sanid;

                                bzero(&sanid, sizeof(sanid));
                                sanid.id_offset = 0;
                                sanid.id_type = type;
                                if ((sanid.id_buf = ibuf_new(data, len))
                                    == NULL) {
                                        log_debug("%s: failed to get id buffer",
                                            __func__);
                                        continue;
                                }
                                ikev2_print_id(&sanid, idstr, sizeof(idstr));
                                log_info("%s: altname: %s", logmsg, idstr);
                                ibuf_free(sanid.id_buf);
                                sanid.id_buf = NULL;
                        }
                        /* Compare length and data */
                        if (mode == MODE_ALT_CMP) {
                                if (type == id->id_type &&
                                    (len == (id->id_length - id->id_offset)) &&
                                    (memcmp(id->id_data + id->id_offset,
                                    data, len)) == 0) {
                                        ret = 0;
                                        break;
                                }
                        }
                        /* Get first ID */
                        if (mode == MODE_ALT_GET) {
                                ibuf_free(retid->id_buf);
                                if ((retid->id_buf = ibuf_new(data, len)) == NULL) {
                                        log_debug("%s: failed to get id buffer",
                                            __func__);
                                        ret = -2;
                                        break;
                                }
                                retid->id_offset = 0;
                                ikev2_print_id(retid, idstr, sizeof(idstr));
                                log_debug("%s: %s", __func__, idstr);
                                ret = 0;
                                break;
                        }
                }
                sk_GENERAL_NAME_pop_free(stack, GENERAL_NAME_free);
        } else if (crit == -2)
                log_info("%s: multiple subjectAltName extensions are invalid",
                    __func__);
        else if (crit == -1)
                log_debug("%s: did not find subjectAltName in certificate",
                    __func__);
        else
                log_debug("%s: failed to decode subjectAltName", __func__);
        return ret;
}

int
ca_x509_subjectaltname_log(X509 *cert, const char *logmsg)
{
        return ca_x509_subjectaltname_do(cert, MODE_ALT_LOG, logmsg, NULL, NULL);
}

int
ca_x509_subjectaltname_cmp(X509 *cert, struct iked_static_id *id)
{
        return ca_x509_subjectaltname_do(cert, MODE_ALT_CMP, NULL, id, NULL);
}

int
ca_x509_subjectaltname_get(X509 *cert, struct iked_id *retid)
{
        return ca_x509_subjectaltname_do(cert, MODE_ALT_GET, NULL, NULL, retid);
}

void
ca_sslerror(const char *caller)
{
        unsigned long    error;

        while ((error = ERR_get_error()) != 0)
                log_warnx("%s: %s: %.100s", __func__, caller,
                    ERR_error_string(error, NULL));
}