conf.c

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/*
 *   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.
 *
 *   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.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program; if not, write to the Free Software
 *   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
 */
 
/**
 * $Id: 5fec103472f42db31d3fbac38fd9f7dbf458a070 $
 *
 * @file tls/conf.c
 * @brief Configuration parsing for TLS servers and clients.
 *
 * @copyright 2026 Network RADIUS SAS (legal@networkradius.com)
 */
RCSID("$Id: 5fec103472f42db31d3fbac38fd9f7dbf458a070 $")
USES_APPLE_DEPRECATED_API       /* OpenSSL API has been deprecated by Apple */
 
#ifdef WITH_TLS
#define LOG_PREFIX "tls"
 
#ifdef HAVE_SYS_STAT_H
#  include <sys/stat.h>
#endif
#include <openssl/conf.h>
#include <openssl/pem.h>
 
#include <freeradius-devel/server/module.h>
#include <freeradius-devel/server/virtual_servers.h>
#include <freeradius-devel/util/debug.h>
#include <freeradius-devel/util/syserror.h>
#include <freeradius-devel/util/rand.h>
#include <freeradius-devel/util/math.h>
 
#include "base.h"
#include "log.h"
#include "strerror.h"
#include "utils.h"
 
static int tls_conf_parse_cache_mode(TALLOC_CTX *ctx, void *out, void *parent, CONF_ITEM *ci, conf_parser_t const *rule);
static int tls_virtual_server_cf_parse(TALLOC_CTX *ctx, void *out, void *parent, CONF_ITEM *ci, conf_parser_t const *rule);
static int tls_fragment_size_parse(TALLOC_CTX *ctx, void *out, void *parent, CONF_ITEM *ci, conf_parser_t const *rule);
static int tls_padding_parse(TALLOC_CTX *ctx, void *out, void *parent, CONF_ITEM *ci, conf_parser_t const *rule);
static int tls_ticket_lifetime_parse(TALLOC_CTX *ctx, void *out, void *parent, CONF_ITEM *ci, conf_parser_t const *rule);
static int tls_chain_private_key_file_parse(TALLOC_CTX *ctx, void *out, void *parent, CONF_ITEM *ci, conf_parser_t const *rule);
 
/** Certificate formats
 *
 */
static fr_table_num_sorted_t const certificate_format_table[] = {
        { L("ASN1"),                    SSL_FILETYPE_ASN1                       },
        { L("DER"),                     SSL_FILETYPE_ASN1                       },      /* Alternate name for ASN1 */
        { L("PEM"),                     SSL_FILETYPE_PEM                        }
};
static size_t certificate_format_table_len = NUM_ELEMENTS(certificate_format_table);
 
static fr_table_num_sorted_t const chain_verify_mode_table[] = {
        { L("hard"),                    FR_TLS_CHAIN_VERIFY_HARD                },
        { L("none"),                    FR_TLS_CHAIN_VERIFY_NONE                },
        { L("soft"),                    FR_TLS_CHAIN_VERIFY_SOFT                }
};
static size_t chain_verify_mode_table_len = NUM_ELEMENTS(chain_verify_mode_table);
 
static fr_table_num_sorted_t const cache_mode_table[] = {
        { L("auto"),                    FR_TLS_TICKET_AUTO                      },
        { L("disabled"),                FR_TLS_TICKET_DISABLED                  },
        { L("stateful"),                FR_TLS_TICKET_STATEFUL                  },
        { L("stateless"),               FR_TLS_TICKET_STATELESS                 }
};
static size_t cache_mode_table_len = NUM_ELEMENTS(cache_mode_table);
 
static fr_table_num_sorted_t const verify_mode_table[] = {
        { L("all"),                     FR_TLS_VERIFY_MODE_ALL          },
        { L("client"),                  FR_TLS_VERIFY_MODE_LEAF         },
        { L("client-and-issuer"),       FR_TLS_VERIFY_MODE_LEAF | FR_TLS_VERIFY_MODE_ISSUER },
        { L("disabled"),                FR_TLS_VERIFY_MODE_DISABLED     },
        { L("untrusted"),               FR_TLS_VERIFY_MODE_UNTRUSTED    }
};
static size_t verify_mode_table_len = NUM_ELEMENTS(verify_mode_table);
 
static conf_parser_t tls_ticket_config[] = {
        { FR_CONF_OFFSET("mode", fr_tls_ticket_conf_t, mode),
                         .func = tls_conf_parse_cache_mode,
                         .uctx = &(cf_table_parse_ctx_t){
                                .table = cache_mode_table,
                                .len = &cache_mode_table_len
                         },
                         .dflt = "auto" },
        { FR_CONF_OFFSET_HINT_TYPE("name", FR_TYPE_STRING, fr_tls_ticket_conf_t, id_name),
                         .dflt = "%{EAP-Type}%interpreter('server')", .quote = T_DOUBLE_QUOTED_STRING },
        { FR_CONF_OFFSET("lifetime", fr_tls_ticket_conf_t, lifetime), .func = tls_ticket_lifetime_parse, .dflt = "1d" },
        { FR_CONF_OFFSET_IS_SET("min_lifetime", FR_TYPE_TIME_DELTA, 0, fr_tls_ticket_conf_t, min_lifetime),
                         .dflt = "10s" },
 
        { FR_CONF_OFFSET("require_extended_master_secret", fr_tls_ticket_conf_t, require_extms), .dflt = "yes" },
        { FR_CONF_OFFSET("require_perfect_forward_secrecy", fr_tls_ticket_conf_t, require_pfs), .dflt = "no" },
 
        { FR_CONF_OFFSET("session_ticket_key", fr_tls_ticket_conf_t, session_ticket_key) },
 
        /*
         *      Deprecated
         */
        { FR_CONF_V3_DEPRECATED("enable", fr_tls_ticket_conf_t, NULL) },
        { FR_CONF_V3_DEPRECATED("max_entries", fr_tls_ticket_conf_t, NULL) },
        { FR_CONF_V3_DEPRECATED("persist_dir", fr_tls_ticket_conf_t, NULL) },
 
        CONF_PARSER_TERMINATOR
};
 
static conf_parser_t tls_chain_config[] = {
        { FR_CONF_OFFSET("format", fr_tls_chain_conf_t, file_format),
                         .func = cf_table_parse_int,
                         .uctx = &(cf_table_parse_ctx_t){
                                .table = certificate_format_table,
                                .len = &certificate_format_table_len
                         },
                         .dflt = "pem" },
        /*
         *      private_key_file must be the last file row.  Its parse
         *      callback loads every file in the section.
         */
        { FR_CONF_OFFSET_FLAGS("ca_file", CONF_FLAG_FILE_READABLE | CONF_FLAG_MULTI, fr_tls_chain_conf_t, ca_files) },
        { FR_CONF_OFFSET_FLAGS("certificate_file", CONF_FLAG_FILE_READABLE | CONF_FLAG_FILE_EXISTS | CONF_FLAG_REQUIRED, fr_tls_chain_conf_t, certificate_file) },
        { FR_CONF_OFFSET_FLAGS("private_key_password", CONF_FLAG_SECRET, fr_tls_chain_conf_t, password) },
        { FR_CONF_OFFSET_FLAGS("private_key_file", CONF_FLAG_FILE_READABLE | CONF_FLAG_FILE_EXISTS | CONF_FLAG_REQUIRED, fr_tls_chain_conf_t, private_key_file),
                         .func = tls_chain_private_key_file_parse },
 
        { FR_CONF_OFFSET("verify_mode", fr_tls_chain_conf_t, verify_mode),
                         .func = cf_table_parse_uint8,
                         .uctx = &(cf_table_parse_ctx_t){
                                .table = chain_verify_mode_table,
                                .len = &chain_verify_mode_table_len
                         },
                         .dflt = "hard" },
        { FR_CONF_OFFSET("include_root_ca", fr_tls_chain_conf_t, include_root_ca), .dflt = "no" },
        CONF_PARSER_TERMINATOR
};
 
static conf_parser_t tls_verify_config[] = {
        { FR_CONF_OFFSET("mode", fr_tls_verify_conf_t, mode),
                         .func = cf_table_parse_uint8,
                         .uctx = &(cf_table_parse_ctx_t){
                                .table = verify_mode_table,
                                .len = &verify_mode_table_len
                         },
                         .dflt = "all" },
        { FR_CONF_OFFSET("attribute_mode", fr_tls_verify_conf_t, attribute_mode),
                         .func = cf_table_parse_uint8,
                         .uctx = &(cf_table_parse_ctx_t){
                                .table = verify_mode_table,
                                .len = &verify_mode_table_len
                         },
                         .dflt = "client-and-issuer" },
        { FR_CONF_OFFSET("der_decode", fr_tls_verify_conf_t, der_decode) },
        CONF_PARSER_TERMINATOR
};
 
#ifdef PSK_MAX_IDENTITY_LEN
static conf_parser_t tls_psk_config[] = {
        { FR_CONF_OFFSET("identity", fr_tls_psk_conf_t, identity) },
        { FR_CONF_OFFSET_FLAGS("key", CONF_FLAG_SECRET, fr_tls_psk_conf_t, key) },
        CONF_PARSER_TERMINATOR
};
#endif
 
conf_parser_t fr_tls_server_config[] = {
        { FR_CONF_OFFSET_TYPE_FLAGS("virtual_server", FR_TYPE_VOID, 0, fr_tls_conf_t, virtual_server), .func = tls_virtual_server_cf_parse },
 
        { FR_CONF_SUBSECTION_ALLOC_MULTI("chain", 0, fr_tls_conf_t, chains, tls_chain_config),
          .subcs_type = "fr_tls_chain_conf_t", .name2 = CF_IDENT_ANY },
 
        { FR_CONF_V3_DEPRECATED("pem_file_type", fr_tls_conf_t, NULL) },
        { FR_CONF_V3_DEPRECATED("certificate_file", fr_tls_conf_t, NULL) },
        { FR_CONF_V3_DEPRECATED("private_key_password", fr_tls_conf_t, NULL) },
        { FR_CONF_V3_DEPRECATED("private_key_file", fr_tls_conf_t, NULL) },
 
        { FR_CONF_OFFSET("verify_depth", fr_tls_conf_t, verify_depth), .dflt = "0" },
        { FR_CONF_OFFSET_FLAGS("ca_path", CONF_FLAG_FILE_READABLE, fr_tls_conf_t, ca_path) },
        { FR_CONF_OFFSET_FLAGS("ca_file", CONF_FLAG_FILE_READABLE, fr_tls_conf_t, ca_file) },
 
#ifdef PSK_MAX_IDENTITY_LEN
        { FR_CONF_OFFSET_SUBSECTION("psk", 0, fr_tls_conf_t, psk, tls_psk_config) },
        { FR_CONF_V3_DEPRECATED("psk_identity", fr_tls_conf_t, NULL) },
        { FR_CONF_V3_DEPRECATED("psk_hexphrase", fr_tls_conf_t, NULL) },
        { FR_CONF_V3_DEPRECATED("psk_query", fr_tls_conf_t, NULL) },
#endif
        { FR_CONF_OFFSET("keylog_file", fr_tls_conf_t, keylog_file) },
 
        { FR_CONF_OFFSET_FLAGS("dh_file", CONF_FLAG_FILE_READABLE, fr_tls_conf_t, dh_file) },
        { FR_CONF_OFFSET("fragment_size", fr_tls_conf_t, fragment_size), .func = tls_fragment_size_parse, .dflt = "1024" },
        { FR_CONF_OFFSET("padding", fr_tls_conf_t, padding_block_size), .func = tls_padding_parse },
 
        { FR_CONF_OFFSET("disable_single_dh_use", fr_tls_conf_t, disable_single_dh_use) },
 
        { FR_CONF_OFFSET("cipher_list", fr_tls_conf_t, cipher_list) },
        { FR_CONF_OFFSET("cipher_suites", fr_tls_conf_t, cipher_suites) },
        { FR_CONF_OFFSET("group_list", fr_tls_conf_t, group_list) },
        { FR_CONF_OFFSET("cipher_server_preference", fr_tls_conf_t, cipher_server_preference), .dflt = "yes" },
#ifdef SSL3_FLAGS_NO_RENEGOTIATE_CIPHERS
        { FR_CONF_OFFSET("allow_renegotiation", fr_tls_conf_t, allow_renegotiation), .dflt = "no" },
#endif
 
#ifndef OPENSSL_NO_ECDH
        { FR_CONF_OFFSET("ecdh_curve", fr_tls_conf_t, ecdh_curve), .dflt = "prime256v1" },
#endif
        { FR_CONF_OFFSET("tls_max_version", fr_tls_conf_t, tls_max_version) },
 
        { FR_CONF_OFFSET("tls_min_version", fr_tls_conf_t, tls_min_version), .dflt = "1.2" },
 
        { FR_CONF_OFFSET("client_hello_parse", fr_tls_conf_t, client_hello_parse )},
 
        { FR_CONF_OFFSET_SUBSECTION("session", 0, fr_tls_conf_t, cache, tls_ticket_config) },
 
        { FR_CONF_OFFSET_SUBSECTION("verify", 0, fr_tls_conf_t, verify, tls_verify_config) },
 
        { FR_CONF_OFFSET_SUBSECTION("cache", CONF_FLAG_V3_DEPRECATED, fr_tls_conf_t, cache, tls_ticket_config) },
        { FR_CONF_V3_DEPRECATED("check_cert_issuer", fr_tls_conf_t, check_cert_issuer) },
        { FR_CONF_V3_DEPRECATED("check_cert_cn", fr_tls_conf_t, check_cert_cn) },
        CONF_PARSER_TERMINATOR
};
 
conf_parser_t fr_tls_client_config[] = {
        /*
         *      Optional.  Without it a client validates the server certificate
         *      with OpenSSL alone, which is what a caller that owns its own
         *      transport wants.  With it, fr_tls_session_alloc_client() runs
         *      the `verify certificate` section of the named virtual server.
         */
        { FR_CONF_OFFSET_TYPE_FLAGS("virtual_server", FR_TYPE_VOID, CONF_FLAG_OK_MISSING, fr_tls_conf_t, virtual_server),
          .func = tls_virtual_server_cf_parse },
 
        { FR_CONF_SUBSECTION_ALLOC_MULTI("chain", CONF_FLAG_OK_MISSING, fr_tls_conf_t, chains, tls_chain_config),
          .subcs_type = "fr_tls_chain_conf_t" },
 
        { FR_CONF_OFFSET_SUBSECTION("verify", 0, fr_tls_conf_t, verify, tls_verify_config) },
 
        { FR_CONF_OFFSET_SUBSECTION("session", 0, fr_tls_conf_t, cache, tls_ticket_config) },
 
        { FR_CONF_V3_DEPRECATED("pem_file_type", fr_tls_conf_t, NULL) },
        { FR_CONF_V3_DEPRECATED("certificate_file", fr_tls_conf_t, NULL) },
        { FR_CONF_V3_DEPRECATED("private_key_password", fr_tls_conf_t, NULL) },
        { FR_CONF_V3_DEPRECATED("private_key_file", fr_tls_conf_t, NULL) },
 
#ifdef PSK_MAX_IDENTITY_LEN
        { FR_CONF_OFFSET_SUBSECTION("psk", 0, fr_tls_conf_t, psk, tls_psk_config) },
        { FR_CONF_V3_DEPRECATED("psk_identity", fr_tls_conf_t, NULL) },
        { FR_CONF_V3_DEPRECATED("psk_hexphrase", fr_tls_conf_t, NULL) },
#endif
 
        { FR_CONF_OFFSET("keylog_file", fr_tls_conf_t, keylog_file) },
 
        { FR_CONF_OFFSET("verify_depth", fr_tls_conf_t, verify_depth), .dflt = "0" },
        { FR_CONF_OFFSET_FLAGS("ca_path", CONF_FLAG_FILE_READABLE, fr_tls_conf_t, ca_path) },
 
        { FR_CONF_OFFSET_FLAGS("ca_file", CONF_FLAG_FILE_READABLE, fr_tls_conf_t, ca_file) },
        { FR_CONF_OFFSET("dh_file", fr_tls_conf_t, dh_file) },
        { FR_CONF_OFFSET("random_file", fr_tls_conf_t, random_file) },
        { FR_CONF_OFFSET("fragment_size", fr_tls_conf_t, fragment_size), .func = tls_fragment_size_parse, .dflt = "1024" },
 
        { FR_CONF_OFFSET("cipher_list", fr_tls_conf_t, cipher_list) },
        { FR_CONF_OFFSET("cipher_suites", fr_tls_conf_t, cipher_suites) },
 
#ifndef OPENSSL_NO_ECDH
        { FR_CONF_OFFSET("ecdh_curve", fr_tls_conf_t, ecdh_curve), .dflt = "prime256v1" },
#endif
 
        { FR_CONF_OFFSET("tls_max_version", fr_tls_conf_t, tls_max_version) },
 
        { FR_CONF_OFFSET("tls_min_version", fr_tls_conf_t, tls_min_version), .dflt = "1.2" },
 
        { FR_CONF_OFFSET_SUBSECTION("cache", CONF_FLAG_V3_DEPRECATED, fr_tls_conf_t, cache, tls_ticket_config) },
        { FR_CONF_V3_DEPRECATED("check_cert_issuer", fr_tls_conf_t, check_cert_issuer) },
        { FR_CONF_V3_DEPRECATED("check_cert_cn", fr_tls_conf_t, check_cert_cn) },
        CONF_PARSER_TERMINATOR
};
 
static int tls_virtual_server_cf_parse(TALLOC_CTX *ctx, void *out, void *parent, CONF_ITEM *ci, conf_parser_t const *rule)
{
        fr_tls_conf_t   *conf = talloc_get_type_abort(parent, fr_tls_conf_t);
        virtual_server_t const  *vs = NULL;
 
        if (virtual_server_cf_parse(ctx, &vs, parent, ci, rule) < 0) return -1;
 
        if (!vs) return 0;
 
        /*
         *      `out` points to conf->virtual_server
         */
        *((CONF_SECTION const **)out) = virtual_server_cs(vs);
        conf->verify_certificate = cf_section_find(conf->virtual_server, "verify", "certificate") ? true : false;
        conf->new_session = cf_section_find(conf->virtual_server, "new", "session") ? true : false;
        conf->establish_session = cf_section_find(conf->virtual_server, "establish", "session") ? true : false;
        conf->fail_session = cf_section_find(conf->virtual_server, "fail", "session") ? true : false;
        conf->encode_session = cf_section_find(conf->virtual_server, "encode", "session") ? true : false;
        conf->decode_session = cf_section_find(conf->virtual_server, "decode", "session") ? true : false;
#ifdef PSK_MAX_IDENTITY_LEN
        conf->load_psk = cf_section_find(conf->virtual_server, "load", "psk") ? true : false;
#else
        if (cf_section_find(conf->virtual_server, "load", "psk")) {
                cf_log_err(ci, "Specified virtual_server has a \"load psk { ... }\" section, "
                           "but OpenSSL was built without PSK support");
                return -1;
        }
#endif
        return 0;
}
 
static int tls_conf_parse_cache_mode(TALLOC_CTX *ctx, void *out, void *parent, CONF_ITEM *ci, conf_parser_t const *rule)
{
        fr_tls_conf_t   *conf = talloc_get_type_abort((uint8_t *)parent - offsetof(fr_tls_conf_t, cache), fr_tls_conf_t);
        int             cache_mode;
 
        if (cf_table_parse_int(ctx, &cache_mode, parent, ci, rule) < 0) return -1;
 
        /*
         *      Ensure our virtual server contains the
         *      correct sections for the specified
         *      cache mode.
         */
        switch (cache_mode) {
        case FR_TLS_TICKET_DISABLED:
        case FR_TLS_TICKET_STATELESS:
                break;
 
        case FR_TLS_TICKET_STATEFUL:
                if (!conf->virtual_server) {
                        cf_log_err(ci, "A virtual_server must be set when session.mode = \"stateful\"");
                error:
                        return -1;
                }
 
                if (!cf_section_find(conf->virtual_server, "load", "session")) {
                        cf_log_err(ci, "Specified virtual_server must contain a \"load session { ... }\" section "
                                   "when session.mode = \"stateful\"");
                        goto error;
                }
 
                if (!cf_section_find(conf->virtual_server, "store", "session")) {
                        cf_log_err(ci, "Specified virtual_server must contain a \"store session { ... }\" section "
                                   "when session.mode = \"stateful\"");
                        goto error;
                }
 
                if (!cf_section_find(conf->virtual_server, "clear", "session")) {
                        cf_log_err(ci, "Specified virtual_server must contain a \"clear session { ... }\" section "
                                   "when session.mode = \"stateful\"");
                        goto error;
                }
 
                if (conf->tls_min_version >= (float)1.3) {
                        cf_log_err(ci, "session.mode = \"stateful\" is not supported with tls_min_version >= 1.3");
                        goto error;
                }
                break;
 
        case FR_TLS_TICKET_AUTO:
                if (!conf->virtual_server) {
                        WARN("A virtual_server must be provided for stateful caching. "
                             "session.mode = \"auto\" rewritten to session.mode = \"stateless\"");
                cache_stateless:
                        cache_mode = FR_TLS_TICKET_STATELESS;
                        break;
                }
 
                if (!cf_section_find(conf->virtual_server, "load", "session")) {
                        cf_log_warn(ci, "Specified virtual_server missing \"load session { ... }\" section. "
                                    "session.mode = \"auto\" rewritten to session.mode = \"stateless\"");
                        goto cache_stateless;
                }
 
                if (!cf_section_find(conf->virtual_server, "store", "session")) {
                        cf_log_warn(ci, "Specified virtual_server missing \"store session { ... }\" section. "
                                    "session.mode = \"auto\" rewritten to session.mode = \"stateless\"");
                        goto cache_stateless;
                }
 
                if (!cf_section_find(conf->virtual_server, "clear", "session")) {
                        cf_log_warn(ci, "Specified virtual_server missing \"clear cache { ... }\" section. "
                                    "session.mode = \"auto\" rewritten to session.mode = \"stateless\"");
                        goto cache_stateless;
                }
 
                if (conf->tls_min_version >= (float)1.3) {
                        cf_log_err(ci, "stateful session-resumption is not supported with tls_min_version >= 1.3. "
                                   "session.mode = \"auto\" rewritten to session.mode = \"stateless\"");
                        goto cache_stateless;
                }
                break;
        }
 
        /*
         *      Generate random, ephemeral, session-ticket keys.
         */
        if (cache_mode & FR_TLS_TICKET_STATELESS) {
                /*
                 *      Fill the key with randomness if one
                 *      wasn't specified by the user.
                 */
                if (!conf->cache.session_ticket_key) {
                        MEM(conf->cache.session_ticket_key = talloc_array(conf, uint8_t, 256));
                        fr_rand_buffer(UNCONST(uint8_t *, conf->cache.session_ticket_key),
                                       talloc_array_length(conf->cache.session_ticket_key));
                }
        }
 
        *((int *)out) = cache_mode;
 
        return 0;
}
 
/** Keep `fragment_size` between 100 and the TLS record limit
 *
 * A TLS record holds at most SSL3_RT_MAX_PLAIN_LENGTH bytes, so a larger
 * fragment size gains nothing.  The EAP RFCs ask for fragments of at least
 * 1020 bytes, but the server accepts down to 100.
 */
static int tls_fragment_size_parse(TALLOC_CTX *ctx, void *out, void *parent, CONF_ITEM *ci, conf_parser_t const *rule)
{
        uint32_t *fragment_size = out;
 
        if (cf_pair_parse_value(ctx, out, parent, ci, rule) < 0) return -1;
 
        if (*fragment_size < 100) {
                cf_log_warn(ci, "Ignoring \"fragment_size = %u\", forcing to \"fragment_size = 100\"", *fragment_size);
                *fragment_size = 100;
        }
        if (*fragment_size > SSL3_RT_MAX_PLAIN_LENGTH) {
                cf_log_warn(ci, "Ignoring \"fragment_size = %u\", forcing to \"fragment_size = %u\"",
                            *fragment_size, (unsigned int)SSL3_RT_MAX_PLAIN_LENGTH);
                *fragment_size = SSL3_RT_MAX_PLAIN_LENGTH;
        }
 
        return 0;
}
 
/** Parse padding, and clamp / round it.
 *
 * - 0 means "no padding"
 * - >256 is clamped to 256
 * - we round to multiples of 16.
 *
 * We mangle the padding before writing it to the configuration,
 * because we can't write to the configuration afterwards, due to
 * mprotect().
 */
static int tls_padding_parse(TALLOC_CTX *ctx, void *out, void *parent, CONF_ITEM *ci, conf_parser_t const *rule)
{
        uint32_t *padding = out;
 
        if (cf_pair_parse_value(ctx, out, parent, ci, rule) < 0) return -1;
 
        if (!*padding) return 0;
 
        if (*padding > FR_TLS_MAX_BLOCK_PADDING) {
                cf_log_warn(ci, "Ignoring \"padding = %u\", forcing to \"padding = %u\"",
                            *padding, (unsigned int) FR_TLS_MAX_BLOCK_PADDING);
                *padding = FR_TLS_MAX_BLOCK_PADDING;
        }
 
        *padding = ROUND_UP_POW2(*padding, FR_TLS_BLOCK_PADDING_MULTIPLE);
 
        return 0;
}
 
/** Keep `session.lifetime` at or below #FR_TLS_MAX_SESSION_LIFETIME
 *
 */
static int tls_ticket_lifetime_parse(TALLOC_CTX *ctx, void *out, void *parent, CONF_ITEM *ci, conf_parser_t const *rule)
{
        fr_time_delta_t         *lifetime = out;
        fr_time_delta_t const   max = fr_time_delta_from_sec(FR_TLS_MAX_SESSION_LIFETIME);
 
        if (cf_pair_parse_value(ctx, out, parent, ci, rule) < 0) return -1;
 
        if (fr_time_delta_gt(*lifetime, max)) {
                cf_log_warn(ci, "Ignoring \"lifetime = %pV\", forcing to \"lifetime = %pV\"",
                            fr_box_time_delta(*lifetime), fr_box_time_delta(max));
                *lifetime = max;
        }
 
        return 0;
}
 
#ifdef __APPLE__
/*
 *      Setting private_key_password to this marker reads the
 *      password from certadmin instead.
 */
static char const *special_string = "Apple:UsecertAdmin";
 
/** Read the private key password from certadmin
 *
 * @param[in,out] chain         whose password is replaced when set to the marker.
 * @param[in] ci                for error messages.
 * @return
 *      - 0 on success, or if the password is not the marker.
 *      - -1 if certadmin failed.
 */
static int tls_chain_password_certadmin(fr_tls_chain_conf_t *chain, CONF_ITEM *ci)
{
        char            cmd[256];
        char            *password, *buf;
        long const      max_password_len = 128;
        FILE            *cmd_pipe;
 
        if (!chain->password) return 0;
        if (strncmp(chain->password, special_string, strlen(special_string)) != 0) return 0;
 
        snprintf(cmd, sizeof(cmd) - 1, "/usr/sbin/certadmin --get-private-key-passphrase \"%s\"",
                 chain->private_key_file);
 
        DEBUG2("Getting private key passphrase using command \"%s\"", cmd);
 
        cmd_pipe = popen(cmd, "r");
        if (!cmd_pipe) {
                cf_log_err(ci, "%s command failed: Unable to get private_key_password", cmd);
                cf_log_err(ci, "Error reading private_key_file %s", chain->private_key_file);
                return -1;
        }
 
        MEM(password = talloc_array(chain, char, max_password_len));
 
        buf = fgets(password, max_password_len, cmd_pipe);
        if (!buf || ferror(cmd_pipe)) {
                pclose(cmd_pipe);
                talloc_free(password);
                cf_log_err(ci, "%s command failed: Unable to get private_key_password", cmd);
                cf_log_err(ci, "Error reading private_key_file %s", chain->private_key_file);
                return -1;
        }
        pclose(cmd_pipe);
 
        /* Get rid of newline at end of password. */
        for (buf = password; buf < (password + max_password_len); buf++) {
                if ((unsigned char)*buf < ' ') {
                        *buf = '\0';
                        goto found;
                }
        }
 
        talloc_free(password);
        cf_log_err(ci, "%s command failed: Unable to get private_key_password", cmd);
        cf_log_err(ci, "Error reading private_key_file %s - password is too long", chain->private_key_file);
        return -1;
 
found:
        DEBUG3("Password from command = \"%s\"", password);
        talloc_const_free(chain->password);
        chain->password = password;
 
        return 0;
}
#endif
 
/** Free the OpenSSL objects that a chain section holds
 */
static int _tls_chain_conf_free(fr_tls_chain_conf_t *chain)
{
        if (chain->leaf) X509_free(chain->leaf);
DIAG_OFF_OPTIONAL(used-but-marked-unused)       /* fix spurious warnings for sk macros */
        if (chain->extra) sk_X509_pop_free(chain->extra, X509_free);
DIAG_ON_OPTIONAL(used-but-marked-unused)
        if (chain->private_key) EVP_PKEY_free(chain->private_key);
 
        return 0;
}
 
/** Read one certificate from a file
 *
 * @param[in] ci                for error messages.
 * @param[in] fp                positioned at the next certificate.
 * @param[in] format            SSL_FILETYPE_PEM or SSL_FILETYPE_ASN1.
 * @param[in] aux               read the PEM auxiliary trust data, as OpenSSL does for the leaf.
 * @return
 *      - The certificate.
 *      - NULL at the end of a PEM file, with the error queue empty.
 *      - NULL on error, with the error left on the queue.
 */
static X509 *tls_chain_cert_read(CONF_ITEM *ci, FILE *fp, int format, bool aux)
{
        X509 *cert;
 
        switch (format) {
        case SSL_FILETYPE_PEM:
                cert = aux ? PEM_read_X509_AUX(fp, NULL, NULL, NULL) : PEM_read_X509(fp, NULL, NULL, NULL);
                if (!cert) {
                        unsigned long err = ERR_peek_last_error();
 
                        /*
                         *      OpenSSL reports the end of a file by writing
                         *      PEM_R_NO_START_LINE to the thread local buffer.
                         */
DIAG_OFF_OPTIONAL(used-but-marked-unused)       /* fix spurious warnings for ERR_GET macros */
                        if ((ERR_GET_LIB(err) == ERR_LIB_PEM) && (ERR_GET_REASON(err) == PEM_R_NO_START_LINE)) {
                                ERR_clear_error();
                        }
DIAG_ON_OPTIONAL(used-but-marked-unused)
                }
                return cert;
 
        case SSL_FILETYPE_ASN1:
                return d2i_X509_fp(fp, NULL);
 
        default:
                cf_log_err(ci, "Unknown certificate format %d", format);
                return NULL;
        }
}
 
/** Load the certificates and the private key of a `chain { ... }` section
 *
 * Reads certificate files in this order:
 *
 *  1. The leaf, then the remaining certificates, from certificate_file.
 *  2. One certificate from each ca_file.
 *  3. The private key from private_key_file.
 *
 * This callback stores the loaded objects in leaf, extra, and private_key,
 * and records the earliest notAfter in valid_until.
 */
static int tls_chain_private_key_file_parse(TALLOC_CTX *ctx, void *out, void *parent, CONF_ITEM *ci, conf_parser_t const *rule)
{
        fr_tls_chain_conf_t     *chain = talloc_get_type_abort(parent, fr_tls_chain_conf_t);
        FILE                    *fp;
        X509                    *cert;
        size_t                  i, ca_cnt;
        int                     n;
 
        if (cf_pair_parse_value(ctx, out, parent, ci, rule) < 0) return -1;
 
#ifdef __APPLE__
        if (tls_chain_password_certadmin(chain, ci) < 0) return -1;
#endif
 
        talloc_set_destructor(chain, _tls_chain_conf_free);
 
        /*
         *      The leaf comes first, then the rest of the chain.
         */
        fp = fopen(chain->certificate_file, "r");
        if (!fp) {
                cf_log_err(ci, "Failed opening certificate_file \"%s\": %s", chain->certificate_file, fr_syserror(errno));
                return -1;
        }
 
        chain->leaf = tls_chain_cert_read(ci, fp, chain->file_format, true);
        if (!chain->leaf) {
                fr_tls_strerror_printf("No certificate found");
                cf_log_perr(ci, "Failed reading certificate_file \"%s\"", chain->certificate_file);
                fclose(fp);
                return -1;
        }
 
        MEM(chain->extra = sk_X509_new_null());
        while ((cert = tls_chain_cert_read(ci, fp, chain->file_format, false))) {
                if (chain->file_format != SSL_FILETYPE_PEM) {
                        X509_free(cert);
                        break;          /* A DER file holds exactly one certificate */
                }
DIAG_OFF_OPTIONAL(used-but-marked-unused)       /* fix spurious warnings for sk macros */
                MEM(sk_X509_push(chain->extra, cert) > 0);
DIAG_ON_OPTIONAL(used-but-marked-unused)
        }
        fclose(fp);
        if (ERR_peek_error()) {
                fr_tls_strerror_printf(NULL);
                cf_log_perr(ci, "Failed reading certificate_file \"%s\"", chain->certificate_file);
                return -1;
        }
 
        /*
         *      One certificate per ca_file.
         */
        ca_cnt = chain->ca_files ? talloc_array_length(chain->ca_files) : 0;
        for (i = 0; i < ca_cnt; i++) {
                fp = fopen(chain->ca_files[i], "r");
                if (!fp) {
                        cf_log_err(ci, "Failed opening ca_file \"%s\": %s", chain->ca_files[i], fr_syserror(errno));
                        return -1;
                }
                cert = tls_chain_cert_read(ci, fp, chain->file_format, false);
                fclose(fp);
                if (!cert) {
                        fr_tls_strerror_printf("No certificate found");
                        cf_log_perr(ci, "Failed reading ca_file \"%s\"", chain->ca_files[i]);
                        return -1;
                }
DIAG_OFF_OPTIONAL(used-but-marked-unused)       /* fix spurious warnings for sk macros */
                MEM(sk_X509_push(chain->extra, cert) > 0);
DIAG_ON_OPTIONAL(used-but-marked-unused)
        }
 
        /*
         *      The password callback stops OpenSSL prompting on stdin
         *      when the key is encrypted and no password is set.
         */
        fp = fopen(chain->private_key_file, "r");
        if (!fp) {
                cf_log_err(ci, "Failed opening private_key_file \"%s\": %s", chain->private_key_file, fr_syserror(errno));
                return -1;
        }
        switch (chain->file_format) {
        case SSL_FILETYPE_PEM:
                chain->private_key = PEM_read_PrivateKey(fp, NULL, fr_tls_session_password_cb,
                                                         UNCONST(char *, chain->password));
                break;
 
        case SSL_FILETYPE_ASN1:
                chain->private_key = d2i_PrivateKey_fp(fp, NULL);
                break;
 
        default:
                fr_assert(0);
                break;
        }
        fclose(fp);
        if (!chain->private_key) {
                fr_tls_strerror_printf(NULL);
                cf_log_perr(ci, "Failed reading private_key_file \"%s\"", chain->private_key_file);
                return -1;
        }
 
        if (X509_check_private_key(chain->leaf, chain->private_key) != 1) {
                fr_tls_strerror_printf(NULL);
                cf_log_perr(ci, "Private key does not match the certificate public key");
                return -1;
        }
 
        /*
         *      Record the earliest notAfter.
         */
        chain->valid_until = fr_unix_time_wrap(0);
DIAG_OFF_OPTIONAL(used-but-marked-unused)       /* fix spurious warnings for sk macros */
        for (n = -1; n < sk_X509_num(chain->extra); n++) {
                time_t not_after;
 
                cert = (n < 0) ? chain->leaf : sk_X509_value(chain->extra, n);
                if (fr_tls_utils_asn1time_to_epoch(&not_after, X509_get0_notAfter(cert)) < 0) {
                        cf_log_perr(ci, "Failed parsing notAfter time of certificate %d in the chain", n + 2);
                        return -1;
                }
                if (!fr_unix_time_ispos(chain->valid_until) ||
                    fr_unix_time_gt(chain->valid_until, fr_unix_time_from_time(not_after))) {
                        chain->valid_until = fr_unix_time_from_time(not_after);
                }
        }
DIAG_ON_OPTIONAL(used-but-marked-unused)
 
        cf_log_debug(ci, "Certificate chain valid until %pV", fr_box_date(chain->valid_until));
 
        return 0;
}
#endif  /* WITH_TLS */