/* $OpenBSD: util.c,v 1.72 2019/06/28 13:32:44 deraadt Exp $     */
/* $EOM: util.c,v 1.23 2000/11/23 12:22:08 niklas Exp $  */

/*
 * Copyright (c) 1998, 1999, 2001 Niklas Hallqvist.  All rights reserved.
 * Copyright (c) 2000, 2001, 2004 Håkan Olsson.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/*
 * This code was written under funding by Ericsson Radio Systems.
 */

#include <sys/types.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <limits.h>
#include <netdb.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <ifaddrs.h>
#include <net/route.h>
#include <net/if.h>

#include "log.h"
#include "message.h"
#include "monitor.h"
#include "transport.h"
#include "util.h"

/*
 * Set if -N is given, allowing name lookups to be done, possibly stalling
 * the daemon for quite a while.
 */
int     allow_name_lookups = 0;

/*
 * XXX These might be turned into inlines or macros, maybe even
 * machine-dependent ones, for performance reasons.
 */
u_int16_t
decode_16(u_int8_t *cp)
{
        return cp[0] << 8 | cp[1];
}

u_int32_t
decode_32(u_int8_t *cp)
{
        return cp[0] << 24 | cp[1] << 16 | cp[2] << 8 | cp[3];
}

void
encode_16(u_int8_t *cp, u_int16_t x)
{
        *cp++ = x >> 8;
        *cp = x & 0xff;
}

void
encode_32(u_int8_t *cp, u_int32_t x)
{
        *cp++ = x >> 24;
        *cp++ = (x >> 16) & 0xff;
        *cp++ = (x >> 8) & 0xff;
        *cp = x & 0xff;
}

/* Check a buffer for all zeroes.  */
int
zero_test(const u_int8_t *p, size_t sz)
{
        while (sz-- > 0)
                if (*p++ != 0)
                        return 0;
        return 1;
}

static __inline int
hex2nibble(char c)
{
        if (c >= '0' && c <= '9')
                return c - '0';
        if (c >= 'a' && c <= 'f')
                return c - 'a' + 10;
        if (c >= 'A' && c <= 'F')
                return c - 'A' + 10;
        return -1;
}

/*
 * Convert hexadecimal string in S to raw binary buffer at BUF sized SZ
 * bytes.  Return 0 if everything is OK, -1 otherwise.
 */
int
hex2raw(char *s, u_int8_t *buf, size_t sz)
{
        u_int8_t *bp;
        char    *p;
        int     tmp;

        if (strlen(s) > sz * 2)
                return -1;
        for (p = s + strlen(s) - 1, bp = &buf[sz - 1]; bp >= buf; bp--) {
                *bp = 0;
                if (p >= s) {
                        tmp = hex2nibble(*p--);
                        if (tmp == -1)
                                return -1;
                        *bp = tmp;
                }
                if (p >= s) {
                        tmp = hex2nibble(*p--);
                        if (tmp == -1)
                                return -1;
                        *bp |= tmp << 4;
                }
        }
        return 0;
}

/*
 * Convert raw binary buffer to a newly allocated hexadecimal string.  Returns
 * NULL if an error occurred.  It is the caller's responsibility to free the
 * returned string.
 */
char *
raw2hex(u_int8_t *buf, size_t sz)
{
        char *s;
        size_t i;

        if ((s = malloc(sz * 2 + 1)) == NULL) {
                log_error("raw2hex: malloc (%lu) failed", (unsigned long)sz * 2 + 1);
                return NULL;
        }

        for (i = 0; i < sz; i++)
                snprintf(s + (2 * i), 2 * (sz - i) + 1, "%02x", buf[i]);

        s[sz * 2] = '\0';
        return s;
}

in_port_t
text2port(char *port_str)
{
        char           *port_str_end;
        long            port_long;
        struct servent *service;

        port_long = strtol(port_str, &port_str_end, 0);
        if (port_str == port_str_end) {
                service = getservbyname(port_str, "udp");
                if (!service) {
                        log_print("text2port: service \"%s\" unknown",
                            port_str);
                        return 0;
                }
                return ntohs(service->s_port);
        } else if (port_long < 1 || port_long > (long)USHRT_MAX) {
                log_print("text2port: port %ld out of range", port_long);
                return 0;
        }
        return port_long;
}

int
text2sockaddr(char *address, char *port, struct sockaddr **sa, sa_family_t af,
    int netmask)
{
        struct addrinfo *ai, hints;
        struct sockaddr_storage tmp_sas;
        struct ifaddrs *ifap, *ifa = NULL, *llifa = NULL;
        char *np = address;
        char ifname[IFNAMSIZ];
        u_char buf[BUFSIZ];
        struct rt_msghdr *rtm;
        struct sockaddr *sa2;
        struct sockaddr_in *sin;
        struct sockaddr_in6 *sin6;
        int fd = 0, seq, len, b;
        pid_t pid;

        bzero(&hints, sizeof hints);
        if (!allow_name_lookups)
                hints.ai_flags = AI_NUMERICHOST;
        hints.ai_family = PF_UNSPEC;
        hints.ai_socktype = SOCK_DGRAM;
        hints.ai_protocol = IPPROTO_UDP;

        if (getaddrinfo(address, port, &hints, &ai)) {
                /*
                 * If the 'default' keyword is used, do a route lookup for
                 * the default route, and use the interface associated with
                 * it to select a source address.
                 */
                if (!strcmp(address, "default")) {
                        fd = socket(AF_ROUTE, SOCK_RAW, af);

                        bzero(buf, sizeof(buf));

                        rtm = (struct rt_msghdr *)buf;
                        rtm->rtm_version = RTM_VERSION;
                        rtm->rtm_type = RTM_GET;
                        rtm->rtm_flags = RTF_UP;
                        rtm->rtm_addrs = RTA_DST;
                        rtm->rtm_seq = seq = arc4random();

                        /* default destination */
                        sa2 = (struct sockaddr *)((char *)rtm + rtm->rtm_hdrlen);
                        switch (af) {
                        case AF_INET: {
                                sin = (struct sockaddr_in *)sa2;
                                sin->sin_len = sizeof(*sin);
                                sin->sin_family = af;
                                break;
                        }
                        case AF_INET6: {
                                sin6 = (struct sockaddr_in6 *)sa2;
                                sin6->sin6_len = sizeof(*sin6);
                                sin6->sin6_family = af;
                                break;
                        }
                        default:
                                close(fd);
                                return -1;
                        }
                        rtm->rtm_addrs |= RTA_NETMASK|RTA_IFP|RTA_IFA;
                        rtm->rtm_msglen = sizeof(*rtm) + sizeof(*sa2);

                        if ((b = write(fd, buf, rtm->rtm_msglen)) == -1) {
                                close(fd);
                                return -1;
                        }

                        pid = getpid();

                        while ((len = read(fd, buf, sizeof(buf))) > 0) {
                                if (len < sizeof(*rtm)) {
                                        close(fd);
                                        return -1;
                                }
                                if (rtm->rtm_version != RTM_VERSION)
                                        continue;

                                if (rtm->rtm_type == RTM_GET &&
                                    rtm->rtm_pid == pid &&
                                    rtm->rtm_seq == seq) {
                                        if (rtm->rtm_errno) {
                                                close(fd);
                                                return -1;
                                        }
                                        break;
                                }
                        }
                        close(fd);

                        if ((rtm->rtm_addrs & (RTA_DST|RTA_GATEWAY)) ==
                            (RTA_DST|RTA_GATEWAY)) {
                                np = if_indextoname(rtm->rtm_index, ifname);
                                if (np == NULL)
                                        return -1;
                        }
                }

                if (getifaddrs(&ifap) != 0)
                        return -1;

                switch (af) {
                default:
                case AF_INET:
                        for (ifa = ifap; ifa; ifa = ifa->ifa_next)
                                if (!strcmp(ifa->ifa_name, np) &&
                                    ifa->ifa_addr != NULL &&
                                    ifa->ifa_addr->sa_family == AF_INET)
                                        break;
                        break;
                case AF_INET6:
                        for (ifa = ifap; ifa; ifa = ifa->ifa_next) {
                                if (!strcmp(ifa->ifa_name, np) &&
                                    ifa->ifa_addr != NULL &&
                                    ifa->ifa_addr->sa_family == AF_INET6) {
                                        if (IN6_IS_ADDR_LINKLOCAL(
                                            &((struct sockaddr_in6 *)
                                            ifa->ifa_addr)->sin6_addr) &&
                                            llifa == NULL)
                                                llifa = ifa;
                                        else
                                                break;
                                }
                        }
                        if (ifa == NULL) {
                                ifa = llifa;
                        }
                        break;
                }

                if (ifa) {
                        if (netmask)
                                memcpy(&tmp_sas, ifa->ifa_netmask,
                                    SA_LEN(ifa->ifa_netmask));
                        else
                                memcpy(&tmp_sas, ifa->ifa_addr,
                                    SA_LEN(ifa->ifa_addr));
                        freeifaddrs(ifap);
                } else {
                        freeifaddrs(ifap);
                        return -1;
                }
        } else {
                memcpy(&tmp_sas, ai->ai_addr, SA_LEN(ai->ai_addr));
                freeaddrinfo(ai);
        }

        *sa = malloc(SA_LEN((struct sockaddr *)&tmp_sas));
        if (!*sa)
                return -1;

        memcpy(*sa, &tmp_sas, SA_LEN((struct sockaddr *)&tmp_sas));
        return 0;
}

/*
 * Convert a sockaddr to text. With zflag non-zero fill out with zeroes,
 * i.e 10.0.0.10 --> "010.000.000.010"
 */
int
sockaddr2text(struct sockaddr *sa, char **address, int zflag)
{
        char    buf[NI_MAXHOST], *token, *bstart, *ep;
        int     addrlen, i, j;
        long    val;

        if (getnameinfo(sa, SA_LEN(sa), buf, sizeof buf, 0, 0,
                        allow_name_lookups ? 0 : NI_NUMERICHOST))
                return -1;

        if (zflag == 0) {
                *address = strdup(buf);
                if (!*address)
                        return -1;
        } else
                switch (sa->sa_family) {
                case AF_INET:
                        addrlen = sizeof "000.000.000.000";
                        *address = malloc(addrlen);
                        if (!*address)
                                return -1;
                        buf[addrlen] = '\0';
                        bstart = buf;
                        **address = '\0';
                        while ((token = strsep(&bstart, ".")) != NULL) {
                                if (strlen(*address) > 12) {
                                        free(*address);
                                        return -1;
                                }
                                val = strtol(token, &ep, 10);
                                if (ep == token || val < (long)0 ||
                                    val > (long)UCHAR_MAX) {
                                        free(*address);
                                        return -1;
                                }
                                snprintf(*address + strlen(*address),
                                    addrlen - strlen(*address), "%03ld", val);
                                if (bstart)
                                        strlcat(*address, ".", addrlen);
                        }
                        break;

                case AF_INET6:
                        /*
                         * XXX In the algorithm below there are some magic
                         * numbers we probably could give explaining names.
                         */
                        addrlen =
                            sizeof "0000:0000:0000:0000:0000:0000:0000:0000";
                        *address = malloc(addrlen);
                        if (!*address)
                                return -1;

                        for (i = 0, j = 0; i < 8; i++) {
                                snprintf((*address) + j, addrlen - j,
                                    "%02x%02x",
                                    ((struct sockaddr_in6 *)sa)->sin6_addr.s6_addr[2*i],
                                    ((struct sockaddr_in6 *)sa)->sin6_addr.s6_addr[2*i + 1]);
                                j += 4;
                                (*address)[j] =
                                    (j < (addrlen - 1)) ? ':' : '\0';
                                j++;
                        }
                        break;

                default:
                        *address = strdup("<error>");
                        if (!*address)
                                return -1;
                }

        return 0;
}

/*
 * sockaddr_addrlen and sockaddr_addrdata return the relevant sockaddr info
 * depending on address family.  Useful to keep other code shorter(/clearer?).
 */
int
sockaddr_addrlen(struct sockaddr *sa)
{
        switch (sa->sa_family) {
        case AF_INET6:
                return sizeof((struct sockaddr_in6 *)sa)->sin6_addr.s6_addr;
        case AF_INET:
                return sizeof((struct sockaddr_in *)sa)->sin_addr.s_addr;
        default:
                log_print("sockaddr_addrlen: unsupported protocol family %d",
                    sa->sa_family);
                return 0;
        }
}

u_int8_t *
sockaddr_addrdata(struct sockaddr *sa)
{
        switch (sa->sa_family) {
        case AF_INET6:
                return (u_int8_t *)&((struct sockaddr_in6 *)sa)->sin6_addr.s6_addr;
        case AF_INET:
                return (u_int8_t *)&((struct sockaddr_in *)sa)->sin_addr.s_addr;
        default:
                log_print("sockaddr_addrdata: unsupported protocol family %d",
                    sa->sa_family);
                return 0;
        }
}

in_port_t
sockaddr_port(struct sockaddr *sa)
{
        switch (sa->sa_family) {
        case AF_INET6:
                return ((struct sockaddr_in6 *)sa)->sin6_port;
        case AF_INET:
                return ((struct sockaddr_in *)sa)->sin_port;
        default:
                log_print("sockaddr_port: unsupported protocol family %d",
                    sa->sa_family);
                return 0;
        }
}

/* Utility function used to set the port of a sockaddr.  */
void
sockaddr_set_port(struct sockaddr *sa, in_port_t port)
{
        switch (sa->sa_family) {
        case AF_INET:
                ((struct sockaddr_in *)sa)->sin_port = htons (port);
                break;

        case AF_INET6:
                ((struct sockaddr_in6 *)sa)->sin6_port = htons (port);
                break;
        }
}

/*
 * Convert network address to text. The network address does not need
 * to be properly aligned.
 */
void
util_ntoa(char **buf, int af, u_int8_t *addr)
{
        struct sockaddr_storage from;
        struct sockaddr *sfrom = (struct sockaddr *) & from;
        socklen_t       fromlen = sizeof from;

        bzero(&from, fromlen);
        sfrom->sa_family = af;

        switch (af) {
        case AF_INET:
                sfrom->sa_len = sizeof(struct sockaddr_in);
                break;
        case AF_INET6:
                sfrom->sa_len = sizeof(struct sockaddr_in6);
                break;
        }

        memcpy(sockaddr_addrdata(sfrom), addr, sockaddr_addrlen(sfrom));

        if (sockaddr2text(sfrom, buf, 0)) {
                log_print("util_ntoa: could not make printable address out "
                    "of sockaddr %p", sfrom);
                *buf = 0;
        }
}

/*
 * Perform sanity check on files containing secret information.
 * Returns -1 on failure, 0 otherwise.
 * Also, if FILE_SIZE is a not a null pointer, store file size here.
 */

int
check_file_secrecy_fd(int fd, char *name, size_t *file_size)
{
        struct stat st;

        if (fstat(fd, &st) == -1) {
                log_error("check_file_secrecy: stat (\"%s\") failed", name);
                return -1;
        }
        if (st.st_uid != 0 && st.st_uid != getuid()) {
                log_print("check_file_secrecy_fd: "
                    "not loading %s - file owner is not process user", name);
                errno = EPERM;
                return -1;
        }
        if ((st.st_mode & (S_IRWXG | S_IRWXO)) != 0) {
                log_print("check_file_secrecy_fd: not loading %s - too open "
                    "permissions", name);
                errno = EPERM;
                return -1;
        }
        if (file_size)
                *file_size = (size_t)st.st_size;

        return 0;
}

/* Calculate timeout.  Returns -1 on error. */
long
get_timeout(struct timespec *timeout)
{
        struct timespec now, result;

        if (clock_gettime(CLOCK_MONOTONIC, &now) == -1)
                return -1;
        timespecsub(timeout, &now, &result);
        return result.tv_sec;
}

int
expand_string(char *label, size_t len, const char *srch, const char *repl)
{
        char *tmp;
        char *p, *q;

        if ((tmp = calloc(1, len)) == NULL) {
                log_error("expand_string: calloc");
                return (-1);
        }
        p = q = label;
        while ((q = strstr(p, srch)) != NULL) {
                *q = '\0';
                if ((strlcat(tmp, p, len) >= len) ||
                    (strlcat(tmp, repl, len) >= len)) {
                        log_print("expand_string: string too long");
                        return (-1);
                }
                q += strlen(srch);
                p = q;
        }
        if (strlcat(tmp, p, len) >= len) {
                log_print("expand_string: string too long");
                return (-1);
        }
        strlcpy(label, tmp, len);       /* always fits */
        free(tmp);

        return (0);
}