openssl/crypto/bio/bss_conn.c

/*
 * Copyright 1995-2018 The OpenSSL Project Authors. All Rights Reserved.
 *
 * Licensed under the Apache License 2.0 (the "License").  You may not use
 * this file except in compliance with the License.  You can obtain a copy
 * in the file LICENSE in the source distribution or at
 * https://www.openssl.org/source/license.html
 */

#include <stdio.h>
#include <errno.h>

#include "bio_lcl.h"

#ifndef OPENSSL_NO_SOCK

typedef struct bio_connect_st {
    int state;
    int connect_family;
    char *param_hostname;
    char *param_service;
    int connect_mode;

    BIO_ADDRINFO *addr_first;
    const BIO_ADDRINFO *addr_iter;
    /*
     * int socket; this will be kept in bio->num so that it is compatible
     * with the bss_sock bio
     */
    /*
     * called when the connection is initially made callback(BIO,state,ret);
     * The callback should return 'ret'.  state is for compatibility with the
     * ssl info_callback
     */
    BIO_info_cb *info_callback;
} BIO_CONNECT;

static int conn_write(BIO *h, const char *buf, int num);
static int conn_read(BIO *h, char *buf, int size);
static int conn_puts(BIO *h, const char *str);
static long conn_ctrl(BIO *h, int cmd, long arg1, void *arg2);
static int conn_new(BIO *h);
static int conn_free(BIO *data);
static long conn_callback_ctrl(BIO *h, int cmd, BIO_info_cb *);

static int conn_state(BIO *b, BIO_CONNECT *c);
static void conn_close_socket(BIO *data);
BIO_CONNECT *BIO_CONNECT_new(void);
void BIO_CONNECT_free(BIO_CONNECT *a);

#define BIO_CONN_S_BEFORE                1
#define BIO_CONN_S_GET_ADDR              2
#define BIO_CONN_S_CREATE_SOCKET         3
#define BIO_CONN_S_CONNECT               4
#define BIO_CONN_S_OK                    5
#define BIO_CONN_S_BLOCKED_CONNECT       6

static const BIO_METHOD methods_connectp = {
    BIO_TYPE_CONNECT,
    "socket connect",
    /* TODO: Convert to new style write function */
    bwrite_conv,
    conn_write,
    /* TODO: Convert to new style read function */
    bread_conv,
    conn_read,
    conn_puts,
    NULL,                       /* conn_gets, */
    conn_ctrl,
    conn_new,
    conn_free,
    conn_callback_ctrl,
};

static int conn_state(BIO *b, BIO_CONNECT *c)
{
    int ret = -1, i;
    BIO_info_cb *cb = NULL;

    if (c->info_callback != NULL)
        cb = c->info_callback;

    for (;;) {
        switch (c->state) {
        case BIO_CONN_S_BEFORE:
            if (c->param_hostname == NULL && c->param_service == NULL) {
                BIOerr(BIO_F_CONN_STATE, BIO_R_NO_HOSTNAME_OR_SERVICE_SPECIFIED);
                ERR_add_error_data(4,
                                   "hostname=", c->param_hostname,
                                   " service=", c->param_service);
                goto exit_loop;
            }
            c->state = BIO_CONN_S_GET_ADDR;
            break;

        case BIO_CONN_S_GET_ADDR:
            {
                int family = AF_UNSPEC;
                switch (c->connect_family) {
                case BIO_FAMILY_IPV6:
                    if (1) { /* This is a trick we use to avoid bit rot.
                              * at least the "else" part will always be
                              * compiled.
                              */
#ifdef AF_INET6
                        family = AF_INET6;
                    } else {
#endif
                        BIOerr(BIO_F_CONN_STATE, BIO_R_UNAVAILABLE_IP_FAMILY);
                        goto exit_loop;
                    }
                    break;
                case BIO_FAMILY_IPV4:
                    family = AF_INET;
                    break;
                case BIO_FAMILY_IPANY:
                    family = AF_UNSPEC;
                    break;
                default:
                    BIOerr(BIO_F_CONN_STATE, BIO_R_UNSUPPORTED_IP_FAMILY);
                    goto exit_loop;
                }
                if (BIO_lookup(c->param_hostname, c->param_service,
                               BIO_LOOKUP_CLIENT,
                               family, SOCK_STREAM, &c->addr_first) == 0)
                    goto exit_loop;
            }
            if (c->addr_first == NULL) {
                BIOerr(BIO_F_CONN_STATE, BIO_R_LOOKUP_RETURNED_NOTHING);
                goto exit_loop;
            }
            c->addr_iter = c->addr_first;
            c->state = BIO_CONN_S_CREATE_SOCKET;
            break;

        case BIO_CONN_S_CREATE_SOCKET:
            ret = BIO_socket(BIO_ADDRINFO_family(c->addr_iter),
                             BIO_ADDRINFO_socktype(c->addr_iter),
                             BIO_ADDRINFO_protocol(c->addr_iter), 0);
            if (ret == (int)INVALID_SOCKET) {
                SYSerr(SYS_F_SOCKET, get_last_socket_error());
                ERR_add_error_data(4,
                                   "hostname=", c->param_hostname,
                                   " service=", c->param_service);
                BIOerr(BIO_F_CONN_STATE, BIO_R_UNABLE_TO_CREATE_SOCKET);
                goto exit_loop;
            }
            b->num = ret;
            c->state = BIO_CONN_S_CONNECT;
            break;

        case BIO_CONN_S_CONNECT:
            BIO_clear_retry_flags(b);
            ret = BIO_connect(b->num, BIO_ADDRINFO_address(c->addr_iter),
                              BIO_SOCK_KEEPALIVE | c->connect_mode);
            b->retry_reason = 0;
            if (ret == 0) {
                if (BIO_sock_should_retry(ret)) {
                    BIO_set_retry_special(b);
                    c->state = BIO_CONN_S_BLOCKED_CONNECT;
                    b->retry_reason = BIO_RR_CONNECT;
                    ERR_clear_error();
                } else if ((c->addr_iter = BIO_ADDRINFO_next(c->addr_iter))
                           != NULL) {
                    /*
                     * if there are more addresses to try, do that first
                     */
                    BIO_closesocket(b->num);
                    c->state = BIO_CONN_S_CREATE_SOCKET;
                    ERR_clear_error();
                    break;
                } else {
                    SYSerr(SYS_F_CONNECT, get_last_socket_error());
                    ERR_add_error_data(4,
                                       "hostname=", c->param_hostname,
                                       " service=", c->param_service);
                    BIOerr(BIO_F_CONN_STATE, BIO_R_CONNECT_ERROR);
                }
                goto exit_loop;
            } else {
                c->state = BIO_CONN_S_OK;
            }
            break;

        case BIO_CONN_S_BLOCKED_CONNECT:
            i = BIO_sock_error(b->num);
            if (i) {
                BIO_clear_retry_flags(b);
                SYSerr(SYS_F_CONNECT, i);
                ERR_add_error_data(4,
                                   "hostname=", c->param_hostname,
                                   " service=", c->param_service);
                BIOerr(BIO_F_CONN_STATE, BIO_R_NBIO_CONNECT_ERROR);
                ret = 0;
                goto exit_loop;
            } else
                c->state = BIO_CONN_S_OK;
            break;

        case BIO_CONN_S_OK:
            ret = 1;
            goto exit_loop;
        default:
            /* abort(); */
            goto exit_loop;
        }

        if (cb != NULL) {
            if ((ret = cb((BIO *)b, c->state, ret)) == 0)
                goto end;
        }
    }

    /* Loop does not exit */
 exit_loop:
    if (cb != NULL)
        ret = cb((BIO *)b, c->state, ret);
 end:
    return ret;
}

BIO_CONNECT *BIO_CONNECT_new(void)
{
    BIO_CONNECT *ret;

    if ((ret = OPENSSL_zalloc(sizeof(*ret))) == NULL) {
        BIOerr(BIO_F_BIO_CONNECT_NEW, ERR_R_MALLOC_FAILURE);
        return NULL;
    }
    ret->state = BIO_CONN_S_BEFORE;
    ret->connect_family = BIO_FAMILY_IPANY;
    return ret;
}

void BIO_CONNECT_free(BIO_CONNECT *a)
{
    if (a == NULL)
        return;
    OPENSSL_free(a->param_hostname);
    OPENSSL_free(a->param_service);
    BIO_ADDRINFO_free(a->addr_first);
    OPENSSL_free(a);
}

const BIO_METHOD *BIO_s_connect(void)
{
    return &methods_connectp;
}

static int conn_new(BIO *bi)
{
    bi->init = 0;
    bi->num = (int)INVALID_SOCKET;
    bi->flags = 0;
    if ((bi->ptr = (char *)BIO_CONNECT_new()) == NULL)
        return 0;
    else
        return 1;
}

static void conn_close_socket(BIO *bio)
{
    BIO_CONNECT *c;

    c = (BIO_CONNECT *)bio->ptr;
    if (bio->num != (int)INVALID_SOCKET) {
        /* Only do a shutdown if things were established */
        if (c->state == BIO_CONN_S_OK)
            shutdown(bio->num, 2);
        BIO_closesocket(bio->num);
        bio->num = (int)INVALID_SOCKET;
    }
}

static int conn_free(BIO *a)
{
    BIO_CONNECT *data;

    if (a == NULL)
        return 0;
    data = (BIO_CONNECT *)a->ptr;

    if (a->shutdown) {
        conn_close_socket(a);
        BIO_CONNECT_free(data);
        a->ptr = NULL;
        a->flags = 0;
        a->init = 0;
    }
    return 1;
}

static int conn_read(BIO *b, char *out, int outl)
{
    int ret = 0;
    BIO_CONNECT *data;

    data = (BIO_CONNECT *)b->ptr;
    if (data->state != BIO_CONN_S_OK) {
        ret = conn_state(b, data);
        if (ret <= 0)
            return ret;
    }

    if (out != NULL) {
        clear_socket_error();
        ret = readsocket(b->num, out, outl);
        BIO_clear_retry_flags(b);
        if (ret <= 0) {
            if (BIO_sock_should_retry(ret))
                BIO_set_retry_read(b);
        }
    }
    return ret;
}

static int conn_write(BIO *b, const char *in, int inl)
{
    int ret;
    BIO_CONNECT *data;

    data = (BIO_CONNECT *)b->ptr;
    if (data->state != BIO_CONN_S_OK) {
        ret = conn_state(b, data);
        if (ret <= 0)
            return ret;
    }

    clear_socket_error();
    ret = writesocket(b->num, in, inl);
    BIO_clear_retry_flags(b);
    if (ret <= 0) {
        if (BIO_sock_should_retry(ret))
            BIO_set_retry_write(b);
    }
    return ret;
}

static long conn_ctrl(BIO *b, int cmd, long num, void *ptr)
{
    BIO *dbio;
    int *ip;
    const char **pptr = NULL;
    long ret = 1;
    BIO_CONNECT *data;

    data = (BIO_CONNECT *)b->ptr;

    switch (cmd) {
    case BIO_CTRL_RESET:
        ret = 0;
        data->state = BIO_CONN_S_BEFORE;
        conn_close_socket(b);
        BIO_ADDRINFO_free(data->addr_first);
        data->addr_first = NULL;
        b->flags = 0;
        break;
    case BIO_C_DO_STATE_MACHINE:
        /* use this one to start the connection */
        if (data->state != BIO_CONN_S_OK)
            ret = (long)conn_state(b, data);
        else
            ret = 1;
        break;
    case BIO_C_GET_CONNECT:
        if (ptr != NULL) {
            pptr = (const char **)ptr;
            if (num == 0) {
                *pptr = data->param_hostname;
            } else if (num == 1) {
                *pptr = data->param_service;
            } else if (num == 2) {
                *pptr = (const char *)BIO_ADDRINFO_address(data->addr_iter);
            } else if (num == 3) {
                switch (BIO_ADDRINFO_family(data->addr_iter)) {
# ifdef AF_INET6
                case AF_INET6:
                    ret = BIO_FAMILY_IPV6;
                    break;
# endif
                case AF_INET:
                    ret = BIO_FAMILY_IPV4;
                    break;
                case 0:
                    ret = data->connect_family;
                    break;
                default:
                    ret = -1;
                    break;
                }
            } else {
                ret = 0;
            }
        } else {
            ret = 0;
        }
        break;
    case BIO_C_SET_CONNECT:
        if (ptr != NULL) {
            b->init = 1;
            if (num == 0) {
                char *hold_service = data->param_service;
                /* We affect the hostname regardless.  However, the input
                 * string might contain a host:service spec, so we must
                 * parse it, which might or might not affect the service
                 */
                OPENSSL_free(data->param_hostname);
                data->param_hostname = NULL;
                ret = BIO_parse_hostserv(ptr,
                                         &data->param_hostname,
                                         &data->param_service,
                                         BIO_PARSE_PRIO_HOST);
                if (hold_service != data->param_service)
                    OPENSSL_free(hold_service);
            } else if (num == 1) {
                OPENSSL_free(data->param_service);
                data->param_service = BUF_strdup(ptr);
            } else if (num == 2) {
                const BIO_ADDR *addr = (const BIO_ADDR *)ptr;
                if (ret) {
                    data->param_hostname = BIO_ADDR_hostname_string(addr, 1);
                    data->param_service = BIO_ADDR_service_string(addr, 1);
                    BIO_ADDRINFO_free(data->addr_first);
                    data->addr_first = NULL;
                    data->addr_iter = NULL;
                }
            } else if (num == 3) {
                data->connect_family = *(int *)ptr;
            } else {
                ret = 0;
            }
        }
        break;
    case BIO_C_SET_NBIO:
        if (num != 0)
            data->connect_mode |= BIO_SOCK_NONBLOCK;
        else
            data->connect_mode &= ~BIO_SOCK_NONBLOCK;
        break;
    case BIO_C_SET_CONNECT_MODE:
        data->connect_mode = (int)num;
        break;
    case BIO_C_GET_FD:
        if (b->init) {
            ip = (int *)ptr;
            if (ip != NULL)
                *ip = b->num;
            ret = b->num;
        } else
            ret = -1;
        break;
    case BIO_CTRL_GET_CLOSE:
        ret = b->shutdown;
        break;
    case BIO_CTRL_SET_CLOSE:
        b->shutdown = (int)num;
        break;
    case BIO_CTRL_PENDING:
    case BIO_CTRL_WPENDING:
        ret = 0;
        break;
    case BIO_CTRL_FLUSH:
        break;
    case BIO_CTRL_DUP:
        {
            dbio = (BIO *)ptr;
            if (data->param_hostname)
                BIO_set_conn_hostname(dbio, data->param_hostname);
            if (data->param_service)
                BIO_set_conn_port(dbio, data->param_service);
            BIO_set_conn_ip_family(dbio, data->connect_family);
            BIO_set_conn_mode(dbio, data->connect_mode);
            /*
             * FIXME: the cast of the function seems unlikely to be a good
             * idea
             */
            (void)BIO_set_info_callback(dbio, data->info_callback);
        }
        break;
    case BIO_CTRL_SET_CALLBACK:
        ret = 0; /* use callback ctrl */
        break;
    case BIO_CTRL_GET_CALLBACK:
        {
            BIO_info_cb **fptr;

            fptr = (BIO_info_cb **)ptr;
            *fptr = data->info_callback;
        }
        break;
    default:
        ret = 0;
        break;
    }
    return ret;
}

static long conn_callback_ctrl(BIO *b, int cmd, BIO_info_cb *fp)
{
    long ret = 1;
    BIO_CONNECT *data;

    data = (BIO_CONNECT *)b->ptr;

    switch (cmd) {
    case BIO_CTRL_SET_CALLBACK:
        {
            data->info_callback = fp;
        }
        break;
    default:
        ret = 0;
        break;
    }
    return ret;
}

static int conn_puts(BIO *bp, const char *str)
{
    int n, ret;

    n = strlen(str);
    ret = conn_write(bp, str, n);
    return ret;
}

BIO *BIO_new_connect(const char *str)
{
    BIO *ret;

    ret = BIO_new(BIO_s_connect());
    if (ret == NULL)
        return NULL;
    if (BIO_set_conn_hostname(ret, str))
        return ret;
    BIO_free(ret);
    return NULL;
}

#endif