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openssh-portable/misc.c

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/* $OpenBSD: misc.c,v 1.196 2024/06/06 17:15:25 djm Exp $ */
/*
* Copyright (c) 2000 Markus Friedl. All rights reserved.
* Copyright (c) 2005-2020 Damien Miller. All rights reserved.
* Copyright (c) 2004 Henning Brauer <henning@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 "includes.h"
#include <sys/types.h>
#include <sys/ioctl.h>
#ifndef WINDOWS
#include <sys/mman.h>
#endif /* WINDOWS */
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/wait.h>
#include <sys/un.h>
#include <limits.h>
#ifdef HAVE_LIBGEN_H
# include <libgen.h>
#endif
#ifdef HAVE_POLL_H
#include <poll.h>
#endif
#ifdef HAVE_NLIST_H
#include <nlist.h>
#endif
#include <signal.h>
#include <stdarg.h>
#include <stdio.h>
#ifdef HAVE_STDINT_H
# include <stdint.h>
#endif
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/tcp.h>
#include <arpa/inet.h>
#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <netdb.h>
#ifdef HAVE_PATHS_H
# include <paths.h>
#include <pwd.h>
#include <grp.h>
#endif
#ifdef SSH_TUN_OPENBSD
#include <net/if.h>
#endif
#include "xmalloc.h"
#include "misc.h"
#include "log.h"
#include "ssh.h"
#include "sshbuf.h"
#include "ssherr.h"
#include "platform.h"
/* remove newline at end of string */
char *
chop(char *s)
{
char *t = s;
while (*t) {
if (*t == '\n' || *t == '\r') {
*t = '\0';
return s;
}
t++;
}
return s;
}
/* remove whitespace from end of string */
void
rtrim(char *s)
{
size_t i;
if ((i = strlen(s)) == 0)
return;
for (i--; i > 0; i--) {
if (isspace((unsigned char)s[i]))
s[i] = '\0';
}
}
/* set/unset filedescriptor to non-blocking */
int
set_nonblock(int fd)
{
int val;
val = fcntl(fd, F_GETFL);
if (val == -1) {
error("fcntl(%d, F_GETFL): %s", fd, strerror(errno));
return (-1);
}
if (val & O_NONBLOCK) {
debug3("fd %d is O_NONBLOCK", fd);
return (0);
}
debug2("fd %d setting O_NONBLOCK", fd);
val |= O_NONBLOCK;
if (fcntl(fd, F_SETFL, val) == -1) {
debug("fcntl(%d, F_SETFL, O_NONBLOCK): %s", fd,
strerror(errno));
return (-1);
}
return (0);
}
int
unset_nonblock(int fd)
{
int val;
val = fcntl(fd, F_GETFL);
if (val == -1) {
error("fcntl(%d, F_GETFL): %s", fd, strerror(errno));
return (-1);
}
if (!(val & O_NONBLOCK)) {
debug3("fd %d is not O_NONBLOCK", fd);
return (0);
}
debug("fd %d clearing O_NONBLOCK", fd);
val &= ~O_NONBLOCK;
if (fcntl(fd, F_SETFL, val) == -1) {
debug("fcntl(%d, F_SETFL, ~O_NONBLOCK): %s",
fd, strerror(errno));
return (-1);
}
return (0);
}
const char *
ssh_gai_strerror(int gaierr)
{
if (gaierr == EAI_SYSTEM && errno != 0)
return strerror(errno);
return gai_strerror(gaierr);
}
/* disable nagle on socket */
void
set_nodelay(int fd)
{
int opt;
socklen_t optlen;
optlen = sizeof opt;
if (getsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &opt, &optlen) == -1) {
debug("getsockopt TCP_NODELAY: %.100s", strerror(errno));
return;
}
if (opt == 1) {
debug2("fd %d is TCP_NODELAY", fd);
return;
}
opt = 1;
debug2("fd %d setting TCP_NODELAY", fd);
if (setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &opt, sizeof opt) == -1)
error("setsockopt TCP_NODELAY: %.100s", strerror(errno));
}
/* Allow local port reuse in TIME_WAIT */
int
set_reuseaddr(int fd)
{
int on = 1;
if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) == -1) {
error("setsockopt SO_REUSEADDR fd %d: %s", fd, strerror(errno));
return -1;
}
return 0;
}
/* Get/set routing domain */
char *
get_rdomain(int fd)
{
#if defined(HAVE_SYS_GET_RDOMAIN)
return sys_get_rdomain(fd);
#elif defined(__OpenBSD__)
int rtable;
char *ret;
socklen_t len = sizeof(rtable);
if (getsockopt(fd, SOL_SOCKET, SO_RTABLE, &rtable, &len) == -1) {
error("Failed to get routing domain for fd %d: %s",
fd, strerror(errno));
return NULL;
}
xasprintf(&ret, "%d", rtable);
return ret;
#else /* defined(__OpenBSD__) */
return NULL;
#endif
}
int
set_rdomain(int fd, const char *name)
{
#if defined(HAVE_SYS_SET_RDOMAIN)
return sys_set_rdomain(fd, name);
#elif defined(__OpenBSD__)
int rtable;
const char *errstr;
if (name == NULL)
return 0; /* default table */
rtable = (int)strtonum(name, 0, 255, &errstr);
if (errstr != NULL) {
/* Shouldn't happen */
error("Invalid routing domain \"%s\": %s", name, errstr);
return -1;
}
if (setsockopt(fd, SOL_SOCKET, SO_RTABLE,
&rtable, sizeof(rtable)) == -1) {
error("Failed to set routing domain %d on fd %d: %s",
rtable, fd, strerror(errno));
return -1;
}
return 0;
#else /* defined(__OpenBSD__) */
error("Setting routing domain is not supported on this platform");
return -1;
#endif
}
int
get_sock_af(int fd)
{
struct sockaddr_storage to;
socklen_t tolen = sizeof(to);
memset(&to, 0, sizeof(to));
if (getsockname(fd, (struct sockaddr *)&to, &tolen) == -1)
return -1;
#ifdef IPV4_IN_IPV6
if (to.ss_family == AF_INET6 &&
IN6_IS_ADDR_V4MAPPED(&((struct sockaddr_in6 *)&to)->sin6_addr))
return AF_INET;
#endif
return to.ss_family;
}
void
set_sock_tos(int fd, int tos)
{
#ifndef IP_TOS_IS_BROKEN
int af;
switch ((af = get_sock_af(fd))) {
case -1:
/* assume not a socket */
break;
case AF_INET:
# ifdef IP_TOS
debug3_f("set socket %d IP_TOS 0x%02x", fd, tos);
if (setsockopt(fd, IPPROTO_IP, IP_TOS,
&tos, sizeof(tos)) == -1) {
error("setsockopt socket %d IP_TOS %d: %s",
fd, tos, strerror(errno));
}
# endif /* IP_TOS */
break;
case AF_INET6:
# ifdef IPV6_TCLASS
debug3_f("set socket %d IPV6_TCLASS 0x%02x", fd, tos);
if (setsockopt(fd, IPPROTO_IPV6, IPV6_TCLASS,
&tos, sizeof(tos)) == -1) {
error("setsockopt socket %d IPV6_TCLASS %d: %s",
fd, tos, strerror(errno));
}
# endif /* IPV6_TCLASS */
break;
default:
debug2_f("unsupported socket family %d", af);
break;
}
#endif /* IP_TOS_IS_BROKEN */
}
/*
* Wait up to *timeoutp milliseconds for events on fd. Updates
* *timeoutp with time remaining.
* Returns 0 if fd ready or -1 on timeout or error (see errno).
*/
static int
waitfd(int fd, int *timeoutp, short events, volatile sig_atomic_t *stop)
{
struct pollfd pfd;
#ifdef WINDOWS
struct timeval t_start;
int oerrno, r, have_timeout = (*timeoutp >= 0);
#else
struct timespec timeout;
int oerrno, r;
sigset_t nsigset, osigset;
if (timeoutp && *timeoutp == -1)
timeoutp = NULL;
#endif /* WINDOWS */
pfd.fd = fd;
pfd.events = events;
#ifdef WINDOWS
/*
* Windows does not support sigprocmask
* which was implemented to handle ctrl+c during multiplexing.
* When Win32-OpenSSH adds multiplexing support, modify and use
* native_sig_handler in contrib/win32/win32compat/signal.c here
*
*/
for (; !have_timeout || *timeoutp >= 0;) {
monotime_tv(&t_start);
r = poll(&pfd, 1, *timeoutp);
#else
ptimeout_init(&timeout);
if (timeoutp != NULL)
ptimeout_deadline_ms(&timeout, *timeoutp);
if (stop != NULL)
sigfillset(&nsigset);
for (; timeoutp == NULL || *timeoutp >= 0;) {
if (stop != NULL) {
sigprocmask(SIG_BLOCK, &nsigset, &osigset);
if (*stop) {
sigprocmask(SIG_SETMASK, &osigset, NULL);
errno = EINTR;
return -1;
}
}
r = ppoll(&pfd, 1, ptimeout_get_tsp(&timeout),
stop != NULL ? &osigset : NULL);
#endif /* WINDOWS */
oerrno = errno;
#ifdef WINDOWS
if (have_timeout)
ms_subtract_diff(&t_start, timeoutp);
#else
if (stop != NULL)
sigprocmask(SIG_SETMASK, &osigset, NULL);
if (timeoutp)
*timeoutp = ptimeout_get_ms(&timeout);
#endif /* WINDOWS */
errno = oerrno;
if (r > 0)
return 0;
else if (r == -1 && errno != EAGAIN && errno != EINTR)
return -1;
else if (r == 0)
break;
}
/* timeout */
errno = ETIMEDOUT;
return -1;
}
/*
* Wait up to *timeoutp milliseconds for fd to be readable. Updates
* *timeoutp with time remaining.
* Returns 0 if fd ready or -1 on timeout or error (see errno).
*/
int
waitrfd(int fd, int *timeoutp, volatile sig_atomic_t *stop) {
return waitfd(fd, timeoutp, POLLIN, stop);
}
/*
* Attempt a non-blocking connect(2) to the specified address, waiting up to
* *timeoutp milliseconds for the connection to complete. If the timeout is
* <=0, then wait indefinitely.
*
* Returns 0 on success or -1 on failure.
*/
int
timeout_connect(int sockfd, const struct sockaddr *serv_addr,
socklen_t addrlen, int *timeoutp)
{
int optval = 0;
socklen_t optlen = sizeof(optval);
/* No timeout: just do a blocking connect() */
if (timeoutp == NULL || *timeoutp <= 0)
return connect(sockfd, serv_addr, addrlen);
set_nonblock(sockfd);
for (;;) {
if (connect(sockfd, serv_addr, addrlen) == 0) {
/* Succeeded already? */
unset_nonblock(sockfd);
return 0;
} else if (errno == EINTR)
continue;
else if (errno != EINPROGRESS)
return -1;
break;
}
if (waitfd(sockfd, timeoutp, POLLIN | POLLOUT, NULL) == -1)
return -1;
/* Completed or failed */
if (getsockopt(sockfd, SOL_SOCKET, SO_ERROR, &optval, &optlen) == -1) {
debug("getsockopt: %s", strerror(errno));
return -1;
}
if (optval != 0) {
errno = optval;
return -1;
}
unset_nonblock(sockfd);
return 0;
}
/* Characters considered whitespace in strsep calls. */
#define WHITESPACE " \t\r\n"
#define QUOTE "\""
/* return next token in configuration line */
static char *
strdelim_internal(char **s, int split_equals)
{
char *old;
int wspace = 0;
if (*s == NULL)
return NULL;
old = *s;
*s = strpbrk(*s,
split_equals ? WHITESPACE QUOTE "=" : WHITESPACE QUOTE);
if (*s == NULL)
return (old);
if (*s[0] == '\"') {
memmove(*s, *s + 1, strlen(*s)); /* move nul too */
/* Find matching quote */
if ((*s = strpbrk(*s, QUOTE)) == NULL) {
return (NULL); /* no matching quote */
} else {
*s[0] = '\0';
*s += strspn(*s + 1, WHITESPACE) + 1;
return (old);
}
}
/* Allow only one '=' to be skipped */
if (split_equals && *s[0] == '=')
wspace = 1;
*s[0] = '\0';
/* Skip any extra whitespace after first token */
*s += strspn(*s + 1, WHITESPACE) + 1;
if (split_equals && *s[0] == '=' && !wspace)
*s += strspn(*s + 1, WHITESPACE) + 1;
return (old);
}
/*
* Return next token in configuration line; splts on whitespace or a
* single '=' character.
*/
char *
strdelim(char **s)
{
return strdelim_internal(s, 1);
}
/*
* Return next token in configuration line; splts on whitespace only.
*/
char *
strdelimw(char **s)
{
return strdelim_internal(s, 0);
}
struct passwd *
pwcopy(struct passwd *pw)
{
struct passwd *copy = xcalloc(1, sizeof(*copy));
copy->pw_name = xstrdup(pw->pw_name);
copy->pw_passwd = xstrdup(pw->pw_passwd == NULL ? "*" : pw->pw_passwd);
#ifdef HAVE_STRUCT_PASSWD_PW_GECOS
copy->pw_gecos = xstrdup(pw->pw_gecos);
#endif
copy->pw_uid = pw->pw_uid;
copy->pw_gid = pw->pw_gid;
#ifdef HAVE_STRUCT_PASSWD_PW_EXPIRE
copy->pw_expire = pw->pw_expire;
#endif
#ifdef HAVE_STRUCT_PASSWD_PW_CHANGE
copy->pw_change = pw->pw_change;
#endif
#ifdef HAVE_STRUCT_PASSWD_PW_CLASS
copy->pw_class = xstrdup(pw->pw_class);
#endif
copy->pw_dir = xstrdup(pw->pw_dir);
copy->pw_shell = xstrdup(pw->pw_shell);
return copy;
}
/*
* Convert ASCII string to TCP/IP port number.
* Port must be >=0 and <=65535.
* Return -1 if invalid.
*/
int
a2port(const char *s)
{
struct servent *se;
long long port;
const char *errstr;
port = strtonum(s, 0, 65535, &errstr);
if (errstr == NULL)
return (int)port;
if ((se = getservbyname(s, "tcp")) != NULL)
return ntohs(se->s_port);
return -1;
}
int
a2tun(const char *s, int *remote)
{
const char *errstr = NULL;
char *sp, *ep;
int tun;
if (remote != NULL) {
*remote = SSH_TUNID_ANY;
sp = xstrdup(s);
if ((ep = strchr(sp, ':')) == NULL) {
free(sp);
return (a2tun(s, NULL));
}
ep[0] = '\0'; ep++;
*remote = a2tun(ep, NULL);
tun = a2tun(sp, NULL);
free(sp);
return (*remote == SSH_TUNID_ERR ? *remote : tun);
}
if (strcasecmp(s, "any") == 0)
return (SSH_TUNID_ANY);
tun = strtonum(s, 0, SSH_TUNID_MAX, &errstr);
if (errstr != NULL)
return (SSH_TUNID_ERR);
return (tun);
}
#define SECONDS 1
#define MINUTES (SECONDS * 60)
#define HOURS (MINUTES * 60)
#define DAYS (HOURS * 24)
#define WEEKS (DAYS * 7)
static char *
scandigits(char *s)
{
while (isdigit((unsigned char)*s))
s++;
return s;
}
/*
* Convert a time string into seconds; format is
* a sequence of:
* time[qualifier]
*
* Valid time qualifiers are:
* <none> seconds
* s|S seconds
* m|M minutes
* h|H hours
* d|D days
* w|W weeks
*
* Examples:
* 90m 90 minutes
* 1h30m 90 minutes
* 2d 2 days
* 1w 1 week
*
* Return -1 if time string is invalid.
*/
int
convtime(const char *s)
{
int secs, total = 0, multiplier;
char *p, *os, *np, c = 0;
const char *errstr;
if (s == NULL || *s == '\0')
return -1;
p = os = strdup(s); /* deal with const */
if (os == NULL)
return -1;
while (*p) {
np = scandigits(p);
if (np) {
c = *np;
*np = '\0';
}
secs = (int)strtonum(p, 0, INT_MAX, &errstr);
if (errstr)
goto fail;
*np = c;
multiplier = 1;
switch (c) {
case '\0':
np--; /* back up */
break;
case 's':
case 'S':
break;
case 'm':
case 'M':
multiplier = MINUTES;
break;
case 'h':
case 'H':
multiplier = HOURS;
break;
case 'd':
case 'D':
multiplier = DAYS;
break;
case 'w':
case 'W':
multiplier = WEEKS;
break;
default:
goto fail;
}
if (secs > INT_MAX / multiplier)
goto fail;
secs *= multiplier;
if (total > INT_MAX - secs)
goto fail;
total += secs;
if (total < 0)
goto fail;
p = ++np;
}
free(os);
return total;
fail:
free(os);
return -1;
}
#define TF_BUFS 8
#define TF_LEN 9
const char *
fmt_timeframe(time_t t)
{
char *buf;
static char tfbuf[TF_BUFS][TF_LEN]; /* ring buffer */
static int idx = 0;
unsigned int sec, min, hrs, day;
unsigned long long week;
buf = tfbuf[idx++];
if (idx == TF_BUFS)
idx = 0;
week = t;
sec = week % 60;
week /= 60;
min = week % 60;
week /= 60;
hrs = week % 24;
week /= 24;
day = week % 7;
week /= 7;
if (week > 0)
snprintf(buf, TF_LEN, "%02lluw%01ud%02uh", week, day, hrs);
else if (day > 0)
snprintf(buf, TF_LEN, "%01ud%02uh%02um", day, hrs, min);
else
snprintf(buf, TF_LEN, "%02u:%02u:%02u", hrs, min, sec);
return (buf);
}
/*
* Returns a standardized host+port identifier string.
* Caller must free returned string.
*/
char *
put_host_port(const char *host, u_short port)
{
char *hoststr;
if (port == 0 || port == SSH_DEFAULT_PORT)
return(xstrdup(host));
if (asprintf(&hoststr, "[%s]:%d", host, (int)port) == -1)
fatal("put_host_port: asprintf: %s", strerror(errno));
debug3("put_host_port: %s", hoststr);
return hoststr;
}
/*
* Search for next delimiter between hostnames/addresses and ports.
* Argument may be modified (for termination).
* Returns *cp if parsing succeeds.
* *cp is set to the start of the next field, if one was found.
* The delimiter char, if present, is stored in delim.
* If this is the last field, *cp is set to NULL.
*/
char *
hpdelim2(char **cp, char *delim)
{
char *s, *old;
if (cp == NULL || *cp == NULL)
return NULL;
old = s = *cp;
if (*s == '[') {
if ((s = strchr(s, ']')) == NULL)
return NULL;
else
s++;
} else if ((s = strpbrk(s, ":/")) == NULL)
s = *cp + strlen(*cp); /* skip to end (see first case below) */
switch (*s) {
case '\0':
*cp = NULL; /* no more fields*/
break;
case ':':
case '/':
if (delim != NULL)
*delim = *s;
*s = '\0'; /* terminate */
*cp = s + 1;
break;
default:
return NULL;
}
return old;
}
/* The common case: only accept colon as delimiter. */
char *
hpdelim(char **cp)
{
char *r, delim = '\0';
r = hpdelim2(cp, &delim);
if (delim == '/')
return NULL;
return r;
}
char *
cleanhostname(char *host)
{
if (*host == '[' && host[strlen(host) - 1] == ']') {
host[strlen(host) - 1] = '\0';
return (host + 1);
} else
return host;
}
char *
colon(char *cp)
{
int flag = 0;
if (*cp == ':') /* Leading colon is part of file name. */
return NULL;
#ifdef WINDOWS
/*
* Account for Windows file names in the form x: or /x:
* Note: This may conflict with potential single character targets
*/
if ((*cp != '\0' && cp[1] == ':') ||
(cp[0] == '/' && cp[1] != '\0' && cp[2] == ':'))
return NULL;
#endif
if (*cp == '[')
flag = 1;
for (; *cp; ++cp) {
if (*cp == '@' && *(cp+1) == '[')
flag = 1;
if (*cp == ']' && *(cp+1) == ':' && flag)
return (cp+1);
if (*cp == ':' && !flag)
return (cp);
if (*cp == '/')
return NULL;
}
return NULL;
}
/*
* Parse a [user@]host:[path] string.
* Caller must free returned user, host and path.
* Any of the pointer return arguments may be NULL (useful for syntax checking).
* If user was not specified then *userp will be set to NULL.
* If host was not specified then *hostp will be set to NULL.
* If path was not specified then *pathp will be set to ".".
* Returns 0 on success, -1 on failure.
*/
int
parse_user_host_path(const char *s, char **userp, char **hostp, char **pathp)
{
char *user = NULL, *host = NULL, *path = NULL;
char *sdup, *tmp;
int ret = -1;
if (userp != NULL)
*userp = NULL;
if (hostp != NULL)
*hostp = NULL;
if (pathp != NULL)
*pathp = NULL;
sdup = xstrdup(s);
/* Check for remote syntax: [user@]host:[path] */
if ((tmp = colon(sdup)) == NULL)
goto out;
/* Extract optional path */
*tmp++ = '\0';
if (*tmp == '\0')
tmp = ".";
path = xstrdup(tmp);
/* Extract optional user and mandatory host */
tmp = strrchr(sdup, '@');
if (tmp != NULL) {
*tmp++ = '\0';
host = xstrdup(cleanhostname(tmp));
if (*sdup != '\0')
user = xstrdup(sdup);
} else {
host = xstrdup(cleanhostname(sdup));
user = NULL;
}
/* Success */
if (userp != NULL) {
*userp = user;
user = NULL;
}
if (hostp != NULL) {
*hostp = host;
host = NULL;
}
if (pathp != NULL) {
*pathp = path;
path = NULL;
}
ret = 0;
out:
free(sdup);
free(user);
free(host);
free(path);
return ret;
}
/*
* Parse a [user@]host[:port] string.
* Caller must free returned user and host.
* Any of the pointer return arguments may be NULL (useful for syntax checking).
* If user was not specified then *userp will be set to NULL.
* If port was not specified then *portp will be -1.
* Returns 0 on success, -1 on failure.
*/
int
parse_user_host_port(const char *s, char **userp, char **hostp, int *portp)
{
char *sdup, *cp, *tmp;
char *user = NULL, *host = NULL;
int port = -1, ret = -1;
if (userp != NULL)
*userp = NULL;
if (hostp != NULL)
*hostp = NULL;
if (portp != NULL)
*portp = -1;
if ((sdup = tmp = strdup(s)) == NULL)
return -1;
/* Extract optional username */
if ((cp = strrchr(tmp, '@')) != NULL) {
*cp = '\0';
if (*tmp == '\0')
goto out;
if ((user = strdup(tmp)) == NULL)
goto out;
tmp = cp + 1;
}
/* Extract mandatory hostname */
if ((cp = hpdelim(&tmp)) == NULL || *cp == '\0')
goto out;
host = xstrdup(cleanhostname(cp));
/* Convert and verify optional port */
if (tmp != NULL && *tmp != '\0') {
if ((port = a2port(tmp)) <= 0)
goto out;
}
/* Success */
if (userp != NULL) {
*userp = user;
user = NULL;
}
if (hostp != NULL) {
*hostp = host;
host = NULL;
}
if (portp != NULL)
*portp = port;
ret = 0;
out:
free(sdup);
free(user);
free(host);
return ret;
}
/*
* Converts a two-byte hex string to decimal.
* Returns the decimal value or -1 for invalid input.
*/
static int
hexchar(const char *s)
{
unsigned char result[2];
int i;
for (i = 0; i < 2; i++) {
if (s[i] >= '0' && s[i] <= '9')
result[i] = (unsigned char)(s[i] - '0');
else if (s[i] >= 'a' && s[i] <= 'f')
result[i] = (unsigned char)(s[i] - 'a') + 10;
else if (s[i] >= 'A' && s[i] <= 'F')
result[i] = (unsigned char)(s[i] - 'A') + 10;
else
return -1;
}
return (result[0] << 4) | result[1];
}
/*
* Decode an url-encoded string.
* Returns a newly allocated string on success or NULL on failure.
*/
static char *
urldecode(const char *src)
{
char *ret, *dst;
int ch;
size_t srclen;
if ((srclen = strlen(src)) >= SIZE_MAX)
fatal_f("input too large");
ret = xmalloc(srclen + 1);
for (dst = ret; *src != '\0'; src++) {
switch (*src) {
case '+':
*dst++ = ' ';
break;
case '%':
if (!isxdigit((unsigned char)src[1]) ||
!isxdigit((unsigned char)src[2]) ||
(ch = hexchar(src + 1)) == -1) {
free(ret);
return NULL;
}
*dst++ = ch;
src += 2;
break;
default:
*dst++ = *src;
break;
}
}
*dst = '\0';
return ret;
}
/*
* Parse an (scp|ssh|sftp)://[user@]host[:port][/path] URI.
* See https://tools.ietf.org/html/draft-ietf-secsh-scp-sftp-ssh-uri-04
* Either user or path may be url-encoded (but not host or port).
* Caller must free returned user, host and path.
* Any of the pointer return arguments may be NULL (useful for syntax checking)
* but the scheme must always be specified.
* If user was not specified then *userp will be set to NULL.
* If port was not specified then *portp will be -1.
* If path was not specified then *pathp will be set to NULL.
* Returns 0 on success, 1 if non-uri/wrong scheme, -1 on error/invalid uri.
*/
int
parse_uri(const char *scheme, const char *uri, char **userp, char **hostp,
int *portp, char **pathp)
{
char *uridup, *cp, *tmp, ch;
char *user = NULL, *host = NULL, *path = NULL;
int port = -1, ret = -1;
size_t len;
len = strlen(scheme);
if (strncmp(uri, scheme, len) != 0 || strncmp(uri + len, "://", 3) != 0)
return 1;
uri += len + 3;
if (userp != NULL)
*userp = NULL;
if (hostp != NULL)
*hostp = NULL;
if (portp != NULL)
*portp = -1;
if (pathp != NULL)
*pathp = NULL;
uridup = tmp = xstrdup(uri);
/* Extract optional ssh-info (username + connection params) */
if ((cp = strchr(tmp, '@')) != NULL) {
char *delim;
#ifdef WINDOWS
/* TODO - This looks to be a core bug in unix code as user can be in UPN format
* The above line should be strrchr() instead of strchr.
* For time being, special handling when username is in User@domain format
*/
char *cp_1 = cp;
if ((cp_1 = strchr(cp + 1, '@')) != NULL)
cp = cp_1;
#endif
*cp = '\0';
/* Extract username and connection params */
if ((delim = strchr(tmp, ';')) != NULL) {
/* Just ignore connection params for now */
*delim = '\0';
}
if (*tmp == '\0') {
/* Empty username */
goto out;
}
if ((user = urldecode(tmp)) == NULL)
goto out;
tmp = cp + 1;
}
/* Extract mandatory hostname */
if ((cp = hpdelim2(&tmp, &ch)) == NULL || *cp == '\0')
goto out;
host = xstrdup(cleanhostname(cp));
if (!valid_domain(host, 0, NULL))
goto out;
if (tmp != NULL && *tmp != '\0') {
if (ch == ':') {
/* Convert and verify port. */
if ((cp = strchr(tmp, '/')) != NULL)
*cp = '\0';
if ((port = a2port(tmp)) <= 0)
goto out;
tmp = cp ? cp + 1 : NULL;
}
if (tmp != NULL && *tmp != '\0') {
/* Extract optional path */
if ((path = urldecode(tmp)) == NULL)
goto out;
}
}
/* Success */
if (userp != NULL) {
*userp = user;
user = NULL;
}
if (hostp != NULL) {
*hostp = host;
host = NULL;
}
if (portp != NULL)
*portp = port;
if (pathp != NULL) {
*pathp = path;
path = NULL;
}
ret = 0;
out:
free(uridup);
free(user);
free(host);
free(path);
return ret;
}
/* function to assist building execv() arguments */
void
addargs(arglist *args, char *fmt, ...)
{
va_list ap;
char *cp;
u_int nalloc;
int r;
va_start(ap, fmt);
r = vasprintf(&cp, fmt, ap);
va_end(ap);
if (r == -1)
fatal_f("argument too long");
nalloc = args->nalloc;
if (args->list == NULL) {
nalloc = 32;
args->num = 0;
} else if (args->num > (256 * 1024))
fatal_f("too many arguments");
else if (args->num >= args->nalloc)
fatal_f("arglist corrupt");
else if (args->num+2 >= nalloc)
nalloc *= 2;
args->list = xrecallocarray(args->list, args->nalloc,
nalloc, sizeof(char *));
args->nalloc = nalloc;
args->list[args->num++] = cp;
args->list[args->num] = NULL;
}
void
replacearg(arglist *args, u_int which, char *fmt, ...)
{
va_list ap;
char *cp;
int r;
va_start(ap, fmt);
r = vasprintf(&cp, fmt, ap);
va_end(ap);
if (r == -1)
fatal_f("argument too long");
if (args->list == NULL || args->num >= args->nalloc)
fatal_f("arglist corrupt");
if (which >= args->num)
fatal_f("tried to replace invalid arg %d >= %d",
which, args->num);
free(args->list[which]);
args->list[which] = cp;
}
void
freeargs(arglist *args)
{
u_int i;
if (args == NULL)
return;
if (args->list != NULL && args->num < args->nalloc) {
for (i = 0; i < args->num; i++)
free(args->list[i]);
free(args->list);
}
args->nalloc = args->num = 0;
args->list = NULL;
}
#ifdef WINDOWS
void
duplicateargs(arglist *dest, const arglist *source)
{
if (!source || !dest)
return;
if (source->list != NULL) {
for (int i = 0; i < source->num; i++) {
addargs(dest, "%s", source->list[i]);
}
}
}
#endif
/*
* Expands tildes in the file name. Returns data allocated by xmalloc.
* Warning: this calls getpw*.
*/
int
tilde_expand(const char *filename, uid_t uid, char **retp)
{
char *ocopy = NULL, *copy, *s = NULL;
const char *path = NULL, *user = NULL;
struct passwd *pw;
size_t len;
int ret = -1, r, slash;
*retp = NULL;
if (*filename != '~') {
*retp = xstrdup(filename);
return 0;
}
ocopy = copy = xstrdup(filename + 1);
if (*copy == '\0') /* ~ */
path = NULL;
else if (*copy == '/') {
copy += strspn(copy, "/");
if (*copy == '\0')
path = NULL; /* ~/ */
else
path = copy; /* ~/path */
} else {
user = copy;
if ((path = strchr(copy, '/')) != NULL) {
copy[path - copy] = '\0';
path++;
path += strspn(path, "/");
if (*path == '\0') /* ~user/ */
path = NULL;
/* else ~user/path */
}
/* else ~user */
}
if (user != NULL) {
if ((pw = getpwnam(user)) == NULL) {
error_f("No such user %s", user);
goto out;
}
} else if ((pw = getpwuid(uid)) == NULL) {
error_f("No such uid %ld", (long)uid);
goto out;
}
/* Make sure directory has a trailing '/' */
slash = (len = strlen(pw->pw_dir)) == 0 || pw->pw_dir[len - 1] != '/';
if ((r = xasprintf(&s, "%s%s%s", pw->pw_dir,
slash ? "/" : "", path != NULL ? path : "")) <= 0) {
error_f("xasprintf failed");
goto out;
}
if (r >= PATH_MAX) {
error_f("Path too long");
goto out;
}
/* success */
ret = 0;
*retp = s;
s = NULL;
out:
free(s);
free(ocopy);
return ret;
}
char *
tilde_expand_filename(const char *filename, uid_t uid)
{
char *ret;
if (tilde_expand(filename, uid, &ret) != 0)
cleanup_exit(255);
return ret;
}
/*
* Expand a string with a set of %[char] escapes and/or ${ENVIRONMENT}
* substitutions. A number of escapes may be specified as
* (char *escape_chars, char *replacement) pairs. The list must be terminated
* by a NULL escape_char. Returns replaced string in memory allocated by
* xmalloc which the caller must free.
*/
static char *
vdollar_percent_expand(int *parseerror, int dollar, int percent,
const char *string, va_list ap)
{
#define EXPAND_MAX_KEYS 64
u_int num_keys = 0, i;
struct {
const char *key;
const char *repl;
} keys[EXPAND_MAX_KEYS];
struct sshbuf *buf;
int r, missingvar = 0;
char *ret = NULL, *var, *varend, *val;
size_t len;
if ((buf = sshbuf_new()) == NULL)
fatal_f("sshbuf_new failed");
if (parseerror == NULL)
fatal_f("null parseerror arg");
*parseerror = 1;
/* Gather keys if we're doing percent expansion. */
if (percent) {
for (num_keys = 0; num_keys < EXPAND_MAX_KEYS; num_keys++) {
keys[num_keys].key = va_arg(ap, char *);
if (keys[num_keys].key == NULL)
break;
keys[num_keys].repl = va_arg(ap, char *);
if (keys[num_keys].repl == NULL) {
fatal_f("NULL replacement for token %s",
keys[num_keys].key);
}
}
if (num_keys == EXPAND_MAX_KEYS && va_arg(ap, char *) != NULL)
fatal_f("too many keys");
if (num_keys == 0)
fatal_f("percent expansion without token list");
}
/* Expand string */
for (i = 0; *string != '\0'; string++) {
/* Optionally process ${ENVIRONMENT} expansions. */
if (dollar && string[0] == '$' && string[1] == '{') {
string += 2; /* skip over '${' */
if ((varend = strchr(string, '}')) == NULL) {
error_f("environment variable '%s' missing "
"closing '}'", string);
goto out;
}
len = varend - string;
if (len == 0) {
error_f("zero-length environment variable");
goto out;
}
var = xmalloc(len + 1);
(void)strlcpy(var, string, len + 1);
if ((val = getenv(var)) == NULL) {
error_f("env var ${%s} has no value", var);
missingvar = 1;
} else {
debug3_f("expand ${%s} -> '%s'", var, val);
if ((r = sshbuf_put(buf, val, strlen(val))) !=0)
fatal_fr(r, "sshbuf_put ${}");
}
free(var);
string += len;
continue;
}
/*
* Process percent expansions if we have a list of TOKENs.
* If we're not doing percent expansion everything just gets
* appended here.
*/
if (*string != '%' || !percent) {
append:
if ((r = sshbuf_put_u8(buf, *string)) != 0)
fatal_fr(r, "sshbuf_put_u8 %%");
continue;
}
string++;
/* %% case */
if (*string == '%')
goto append;
if (*string == '\0') {
error_f("invalid format");
goto out;
}
for (i = 0; i < num_keys; i++) {
if (strchr(keys[i].key, *string) != NULL) {
if ((r = sshbuf_put(buf, keys[i].repl,
strlen(keys[i].repl))) != 0)
fatal_fr(r, "sshbuf_put %%-repl");
break;
}
}
if (i >= num_keys) {
error_f("unknown key %%%c", *string);
goto out;
}
}
if (!missingvar && (ret = sshbuf_dup_string(buf)) == NULL)
fatal_f("sshbuf_dup_string failed");
*parseerror = 0;
out:
sshbuf_free(buf);
return *parseerror ? NULL : ret;
#undef EXPAND_MAX_KEYS
}
/*
* Expand only environment variables.
* Note that although this function is variadic like the other similar
* functions, any such arguments will be unused.
*/
char *
dollar_expand(int *parseerr, const char *string, ...)
{
char *ret;
int err;
va_list ap;
va_start(ap, string);
ret = vdollar_percent_expand(&err, 1, 0, string, ap);
va_end(ap);
if (parseerr != NULL)
*parseerr = err;
return ret;
}
/*
* Returns expanded string or NULL if a specified environment variable is
* not defined, or calls fatal if the string is invalid.
*/
char *
percent_expand(const char *string, ...)
{
char *ret;
int err;
va_list ap;
va_start(ap, string);
ret = vdollar_percent_expand(&err, 0, 1, string, ap);
va_end(ap);
if (err)
fatal_f("failed");
return ret;
}
/*
* Returns expanded string or NULL if a specified environment variable is
* not defined, or calls fatal if the string is invalid.
*/
char *
percent_dollar_expand(const char *string, ...)
{
char *ret;
int err;
va_list ap;
va_start(ap, string);
ret = vdollar_percent_expand(&err, 1, 1, string, ap);
va_end(ap);
if (err)
fatal_f("failed");
return ret;
}
int
tun_open(int tun, int mode, char **ifname)
{
#if defined(CUSTOM_SYS_TUN_OPEN)
return (sys_tun_open(tun, mode, ifname));
#elif defined(SSH_TUN_OPENBSD)
struct ifreq ifr;
char name[100];
int fd = -1, sock;
const char *tunbase = "tun";
if (ifname != NULL)
*ifname = NULL;
if (mode == SSH_TUNMODE_ETHERNET)
tunbase = "tap";
/* Open the tunnel device */
if (tun <= SSH_TUNID_MAX) {
snprintf(name, sizeof(name), "/dev/%s%d", tunbase, tun);
fd = open(name, O_RDWR);
} else if (tun == SSH_TUNID_ANY) {
for (tun = 100; tun >= 0; tun--) {
snprintf(name, sizeof(name), "/dev/%s%d",
tunbase, tun);
if ((fd = open(name, O_RDWR)) >= 0)
break;
}
} else {
debug_f("invalid tunnel %u", tun);
return -1;
}
if (fd == -1) {
debug_f("%s open: %s", name, strerror(errno));
return -1;
}
debug_f("%s mode %d fd %d", name, mode, fd);
/* Bring interface up if it is not already */
snprintf(ifr.ifr_name, sizeof(ifr.ifr_name), "%s%d", tunbase, tun);
if ((sock = socket(PF_UNIX, SOCK_STREAM, 0)) == -1)
goto failed;
if (ioctl(sock, SIOCGIFFLAGS, &ifr) == -1) {
debug_f("get interface %s flags: %s", ifr.ifr_name,
strerror(errno));
goto failed;
}
if (!(ifr.ifr_flags & IFF_UP)) {
ifr.ifr_flags |= IFF_UP;
if (ioctl(sock, SIOCSIFFLAGS, &ifr) == -1) {
debug_f("activate interface %s: %s", ifr.ifr_name,
strerror(errno));
goto failed;
}
}
if (ifname != NULL)
*ifname = xstrdup(ifr.ifr_name);
close(sock);
return fd;
failed:
if (fd >= 0)
close(fd);
if (sock >= 0)
close(sock);
return -1;
#else
error("Tunnel interfaces are not supported on this platform");
return (-1);
#endif
}
void
sanitise_stdfd(void)
{
int nullfd, dupfd;
if ((nullfd = dupfd = open(_PATH_DEVNULL, O_RDWR)) == -1) {
fprintf(stderr, "Couldn't open /dev/null: %s\n",
strerror(errno));
exit(1);
}
while (++dupfd <= STDERR_FILENO) {
/* Only populate closed fds. */
if (fcntl(dupfd, F_GETFL) == -1 && errno == EBADF) {
if (dup2(nullfd, dupfd) == -1) {
fprintf(stderr, "dup2: %s\n", strerror(errno));
exit(1);
}
}
}
if (nullfd > STDERR_FILENO)
close(nullfd);
}
char *
tohex(const void *vp, size_t l)
{
const u_char *p = (const u_char *)vp;
char b[3], *r;
size_t i, hl;
if (l > 65536)
return xstrdup("tohex: length > 65536");
hl = l * 2 + 1;
r = xcalloc(1, hl);
for (i = 0; i < l; i++) {
snprintf(b, sizeof(b), "%02x", p[i]);
strlcat(r, b, hl);
}
return (r);
}
/*
* Extend string *sp by the specified format. If *sp is not NULL (or empty),
* then the separator 'sep' will be prepended before the formatted arguments.
* Extended strings are heap allocated.
*/
void
xextendf(char **sp, const char *sep, const char *fmt, ...)
{
va_list ap;
char *tmp1, *tmp2;
va_start(ap, fmt);
xvasprintf(&tmp1, fmt, ap);
va_end(ap);
if (*sp == NULL || **sp == '\0') {
free(*sp);
*sp = tmp1;
return;
}
xasprintf(&tmp2, "%s%s%s", *sp, sep == NULL ? "" : sep, tmp1);
free(tmp1);
free(*sp);
*sp = tmp2;
}
u_int64_t
get_u64(const void *vp)
{
const u_char *p = (const u_char *)vp;
u_int64_t v;
v = (u_int64_t)p[0] << 56;
v |= (u_int64_t)p[1] << 48;
v |= (u_int64_t)p[2] << 40;
v |= (u_int64_t)p[3] << 32;
v |= (u_int64_t)p[4] << 24;
v |= (u_int64_t)p[5] << 16;
v |= (u_int64_t)p[6] << 8;
v |= (u_int64_t)p[7];
return (v);
}
u_int32_t
get_u32(const void *vp)
{
const u_char *p = (const u_char *)vp;
u_int32_t v;
v = (u_int32_t)p[0] << 24;
v |= (u_int32_t)p[1] << 16;
v |= (u_int32_t)p[2] << 8;
v |= (u_int32_t)p[3];
return (v);
}
u_int32_t
get_u32_le(const void *vp)
{
const u_char *p = (const u_char *)vp;
u_int32_t v;
v = (u_int32_t)p[0];
v |= (u_int32_t)p[1] << 8;
v |= (u_int32_t)p[2] << 16;
v |= (u_int32_t)p[3] << 24;
return (v);
}
u_int16_t
get_u16(const void *vp)
{
const u_char *p = (const u_char *)vp;
u_int16_t v;
v = (u_int16_t)p[0] << 8;
v |= (u_int16_t)p[1];
return (v);
}
void
put_u64(void *vp, u_int64_t v)
{
u_char *p = (u_char *)vp;
p[0] = (u_char)(v >> 56) & 0xff;
p[1] = (u_char)(v >> 48) & 0xff;
p[2] = (u_char)(v >> 40) & 0xff;
p[3] = (u_char)(v >> 32) & 0xff;
p[4] = (u_char)(v >> 24) & 0xff;
p[5] = (u_char)(v >> 16) & 0xff;
p[6] = (u_char)(v >> 8) & 0xff;
p[7] = (u_char)v & 0xff;
}
void
put_u32(void *vp, u_int32_t v)
{
u_char *p = (u_char *)vp;
p[0] = (u_char)(v >> 24) & 0xff;
p[1] = (u_char)(v >> 16) & 0xff;
p[2] = (u_char)(v >> 8) & 0xff;
p[3] = (u_char)v & 0xff;
}
void
put_u32_le(void *vp, u_int32_t v)
{
u_char *p = (u_char *)vp;
p[0] = (u_char)v & 0xff;
p[1] = (u_char)(v >> 8) & 0xff;
p[2] = (u_char)(v >> 16) & 0xff;
p[3] = (u_char)(v >> 24) & 0xff;
}
void
put_u16(void *vp, u_int16_t v)
{
u_char *p = (u_char *)vp;
p[0] = (u_char)(v >> 8) & 0xff;
p[1] = (u_char)v & 0xff;
}
void
ms_subtract_diff(struct timeval *start, int *ms)
{
struct timeval diff, finish;
monotime_tv(&finish);
timersub(&finish, start, &diff);
*ms -= (diff.tv_sec * 1000) + (diff.tv_usec / 1000);
}
void
ms_to_timespec(struct timespec *ts, int ms)
{
if (ms < 0)
ms = 0;
ts->tv_sec = ms / 1000;
ts->tv_nsec = (ms % 1000) * 1000 * 1000;
}
void
monotime_ts(struct timespec *ts)
{
struct timeval tv;
#if defined(HAVE_CLOCK_GETTIME) && (defined(CLOCK_BOOTTIME) || \
defined(CLOCK_MONOTONIC) || defined(CLOCK_REALTIME))
static int gettime_failed = 0;
if (!gettime_failed) {
# ifdef CLOCK_BOOTTIME
if (clock_gettime(CLOCK_BOOTTIME, ts) == 0)
return;
# endif /* CLOCK_BOOTTIME */
# ifdef CLOCK_MONOTONIC
if (clock_gettime(CLOCK_MONOTONIC, ts) == 0)
return;
# endif /* CLOCK_MONOTONIC */
# ifdef CLOCK_REALTIME
/* Not monotonic, but we're almost out of options here. */
if (clock_gettime(CLOCK_REALTIME, ts) == 0)
return;
# endif /* CLOCK_REALTIME */
debug3("clock_gettime: %s", strerror(errno));
gettime_failed = 1;
}
#endif /* HAVE_CLOCK_GETTIME && (BOOTTIME || MONOTONIC || REALTIME) */
gettimeofday(&tv, NULL);
ts->tv_sec = tv.tv_sec;
ts->tv_nsec = (long)tv.tv_usec * 1000;
}
void
monotime_tv(struct timeval *tv)
{
struct timespec ts;
monotime_ts(&ts);
tv->tv_sec = ts.tv_sec;
tv->tv_usec = ts.tv_nsec / 1000;
}
time_t
monotime(void)
{
struct timespec ts;
monotime_ts(&ts);
return ts.tv_sec;
}
double
monotime_double(void)
{
struct timespec ts;
monotime_ts(&ts);
return ts.tv_sec + ((double)ts.tv_nsec / 1000000000);
}
void
bandwidth_limit_init(struct bwlimit *bw, u_int64_t kbps, size_t buflen)
{
bw->buflen = buflen;
bw->rate = kbps;
bw->thresh = buflen;
bw->lamt = 0;
timerclear(&bw->bwstart);
timerclear(&bw->bwend);
}
/* Callback from read/write loop to insert bandwidth-limiting delays */
void
bandwidth_limit(struct bwlimit *bw, size_t read_len)
{
u_int64_t waitlen;
struct timespec ts, rm;
bw->lamt += read_len;
if (!timerisset(&bw->bwstart)) {
monotime_tv(&bw->bwstart);
return;
}
if (bw->lamt < bw->thresh)
return;
monotime_tv(&bw->bwend);
timersub(&bw->bwend, &bw->bwstart, &bw->bwend);
if (!timerisset(&bw->bwend))
return;
bw->lamt *= 8;
waitlen = (double)1000000L * bw->lamt / bw->rate;
bw->bwstart.tv_sec = waitlen / 1000000L;
bw->bwstart.tv_usec = waitlen % 1000000L;
if (timercmp(&bw->bwstart, &bw->bwend, >)) {
timersub(&bw->bwstart, &bw->bwend, &bw->bwend);
/* Adjust the wait time */
if (bw->bwend.tv_sec) {
bw->thresh /= 2;
if (bw->thresh < bw->buflen / 4)
bw->thresh = bw->buflen / 4;
} else if (bw->bwend.tv_usec < 10000) {
bw->thresh *= 2;
if (bw->thresh > bw->buflen * 8)
bw->thresh = bw->buflen * 8;
}
TIMEVAL_TO_TIMESPEC(&bw->bwend, &ts);
while (nanosleep(&ts, &rm) == -1) {
if (errno != EINTR)
break;
ts = rm;
}
}
bw->lamt = 0;
monotime_tv(&bw->bwstart);
}
/* Make a template filename for mk[sd]temp() */
void
mktemp_proto(char *s, size_t len)
{
const char *tmpdir;
int r;
tmpdir = getenv("TMPDIR");
#ifdef WINDOWS
if (tmpdir == NULL) {
tmpdir = getenv("TEMP");
}
#endif
if (tmpdir != NULL) {
r = snprintf(s, len, "%s/ssh-XXXXXXXXXXXX", tmpdir);
if (r > 0 && (size_t)r < len)
return;
}
r = snprintf(s, len, "/tmp/ssh-XXXXXXXXXXXX");
if (r < 0 || (size_t)r >= len)
fatal_f("template string too short");
}
static const struct {
const char *name;
int value;
} ipqos[] = {
{ "none", INT_MAX }, /* can't use 0 here; that's CS0 */
{ "af11", IPTOS_DSCP_AF11 },
{ "af12", IPTOS_DSCP_AF12 },
{ "af13", IPTOS_DSCP_AF13 },
{ "af21", IPTOS_DSCP_AF21 },
{ "af22", IPTOS_DSCP_AF22 },
{ "af23", IPTOS_DSCP_AF23 },
{ "af31", IPTOS_DSCP_AF31 },
{ "af32", IPTOS_DSCP_AF32 },
{ "af33", IPTOS_DSCP_AF33 },
{ "af41", IPTOS_DSCP_AF41 },
{ "af42", IPTOS_DSCP_AF42 },
{ "af43", IPTOS_DSCP_AF43 },
{ "cs0", IPTOS_DSCP_CS0 },
{ "cs1", IPTOS_DSCP_CS1 },
{ "cs2", IPTOS_DSCP_CS2 },
{ "cs3", IPTOS_DSCP_CS3 },
{ "cs4", IPTOS_DSCP_CS4 },
{ "cs5", IPTOS_DSCP_CS5 },
{ "cs6", IPTOS_DSCP_CS6 },
{ "cs7", IPTOS_DSCP_CS7 },
{ "ef", IPTOS_DSCP_EF },
{ "le", IPTOS_DSCP_LE },
{ "lowdelay", IPTOS_LOWDELAY },
{ "throughput", IPTOS_THROUGHPUT },
{ "reliability", IPTOS_RELIABILITY },
{ NULL, -1 }
};
int
parse_ipqos(const char *cp)
{
const char *errstr;
u_int i;
int val;
if (cp == NULL)
return -1;
for (i = 0; ipqos[i].name != NULL; i++) {
if (strcasecmp(cp, ipqos[i].name) == 0)
return ipqos[i].value;
}
/* Try parsing as an integer */
val = (int)strtonum(cp, 0, 255, &errstr);
if (errstr)
return -1;
return val;
}
const char *
iptos2str(int iptos)
{
int i;
static char iptos_str[sizeof "0xff"];
for (i = 0; ipqos[i].name != NULL; i++) {
if (ipqos[i].value == iptos)
return ipqos[i].name;
}
snprintf(iptos_str, sizeof iptos_str, "0x%02x", iptos);
return iptos_str;
}
void
lowercase(char *s)
{
for (; *s; s++)
*s = tolower((u_char)*s);
}
int
unix_listener(const char *path, int backlog, int unlink_first)
{
struct sockaddr_un sunaddr;
int saved_errno, sock;
memset(&sunaddr, 0, sizeof(sunaddr));
sunaddr.sun_family = AF_UNIX;
if (strlcpy(sunaddr.sun_path, path,
sizeof(sunaddr.sun_path)) >= sizeof(sunaddr.sun_path)) {
error_f("path \"%s\" too long for Unix domain socket", path);
errno = ENAMETOOLONG;
return -1;
}
sock = socket(PF_UNIX, SOCK_STREAM, 0);
if (sock == -1) {
saved_errno = errno;
error_f("socket: %.100s", strerror(errno));
errno = saved_errno;
return -1;
}
if (unlink_first == 1) {
if (unlink(path) != 0 && errno != ENOENT)
error("unlink(%s): %.100s", path, strerror(errno));
}
if (bind(sock, (struct sockaddr *)&sunaddr, sizeof(sunaddr)) == -1) {
saved_errno = errno;
error_f("cannot bind to path %s: %s", path, strerror(errno));
close(sock);
errno = saved_errno;
return -1;
}
if (listen(sock, backlog) == -1) {
saved_errno = errno;
error_f("cannot listen on path %s: %s", path, strerror(errno));
close(sock);
unlink(path);
errno = saved_errno;
return -1;
}
return sock;
}
void
sock_set_v6only(int s)
{
#if defined(IPV6_V6ONLY) && !defined(__OpenBSD__)
int on = 1;
debug3("%s: set socket %d IPV6_V6ONLY", __func__, s);
if (setsockopt(s, IPPROTO_IPV6, IPV6_V6ONLY, &on, sizeof(on)) == -1)
error("setsockopt IPV6_V6ONLY: %s", strerror(errno));
#endif
}
/*
* Compares two strings that maybe be NULL. Returns non-zero if strings
* are both NULL or are identical, returns zero otherwise.
*/
static int
strcmp_maybe_null(const char *a, const char *b)
{
if ((a == NULL && b != NULL) || (a != NULL && b == NULL))
return 0;
if (a != NULL && strcmp(a, b) != 0)
return 0;
return 1;
}
/*
* Compare two forwards, returning non-zero if they are identical or
* zero otherwise.
*/
int
forward_equals(const struct Forward *a, const struct Forward *b)
{
if (strcmp_maybe_null(a->listen_host, b->listen_host) == 0)
return 0;
if (a->listen_port != b->listen_port)
return 0;
if (strcmp_maybe_null(a->listen_path, b->listen_path) == 0)
return 0;
if (strcmp_maybe_null(a->connect_host, b->connect_host) == 0)
return 0;
if (a->connect_port != b->connect_port)
return 0;
if (strcmp_maybe_null(a->connect_path, b->connect_path) == 0)
return 0;
/* allocated_port and handle are not checked */
return 1;
}
/* returns port number, FWD_PERMIT_ANY_PORT or -1 on error */
int
permitopen_port(const char *p)
{
int port;
if (strcmp(p, "*") == 0)
return FWD_PERMIT_ANY_PORT;
if ((port = a2port(p)) > 0)
return port;
return -1;
}
/* returns 1 if process is already daemonized, 0 otherwise */
#ifdef WINDOWS
/* This should go away once sshd platform specific startup code is refactored */
int
daemonized(void)
{
return 1;
}
#else /* !WINDOWS */
int
daemonized(void)
{
int fd;
if ((fd = open(_PATH_TTY, O_RDONLY | O_NOCTTY)) >= 0) {
close(fd);
return 0; /* have controlling terminal */
}
if (getppid() != 1)
return 0; /* parent is not init */
if (getsid(0) != getpid())
return 0; /* not session leader */
debug3("already daemonized");
return 1;
}
#endif /* !WINDOWS */
/*
* Splits 's' into an argument vector. Handles quoted string and basic
* escape characters (\\, \", \'). Caller must free the argument vector
* and its members.
*/
int
argv_split(const char *s, int *argcp, char ***argvp, int terminate_on_comment)
{
int r = SSH_ERR_INTERNAL_ERROR;
int argc = 0, quote, i, j;
char *arg, **argv = xcalloc(1, sizeof(*argv));
*argvp = NULL;
*argcp = 0;
for (i = 0; s[i] != '\0'; i++) {
/* Skip leading whitespace */
if (s[i] == ' ' || s[i] == '\t')
continue;
if (terminate_on_comment && s[i] == '#')
break;
/* Start of a token */
quote = 0;
argv = xreallocarray(argv, (argc + 2), sizeof(*argv));
arg = argv[argc++] = xcalloc(1, strlen(s + i) + 1);
argv[argc] = NULL;
/* Copy the token in, removing escapes */
for (j = 0; s[i] != '\0'; i++) {
if (s[i] == '\\') {
if (s[i + 1] == '\'' ||
s[i + 1] == '\"' ||
s[i + 1] == '\\' ||
(quote == 0 && s[i + 1] == ' ')) {
i++; /* Skip '\' */
arg[j++] = s[i];
} else {
/* Unrecognised escape */
arg[j++] = s[i];
}
} else if (quote == 0 && (s[i] == ' ' || s[i] == '\t'))
break; /* done */
else if (quote == 0 && (s[i] == '\"' || s[i] == '\''))
quote = s[i]; /* quote start */
else if (quote != 0 && s[i] == quote)
quote = 0; /* quote end */
else
arg[j++] = s[i];
}
if (s[i] == '\0') {
if (quote != 0) {
/* Ran out of string looking for close quote */
r = SSH_ERR_INVALID_FORMAT;
goto out;
}
break;
}
}
/* Success */
*argcp = argc;
*argvp = argv;
argc = 0;
argv = NULL;
r = 0;
out:
if (argc != 0 && argv != NULL) {
for (i = 0; i < argc; i++)
free(argv[i]);
free(argv);
}
return r;
}
/*
* Reassemble an argument vector into a string, quoting and escaping as
* necessary. Caller must free returned string.
*/
char *
argv_assemble(int argc, char **argv)
{
int i, j, ws, r;
char c, *ret;
struct sshbuf *buf, *arg;
if ((buf = sshbuf_new()) == NULL || (arg = sshbuf_new()) == NULL)
fatal_f("sshbuf_new failed");
for (i = 0; i < argc; i++) {
ws = 0;
sshbuf_reset(arg);
for (j = 0; argv[i][j] != '\0'; j++) {
r = 0;
c = argv[i][j];
switch (c) {
case ' ':
case '\t':
ws = 1;
r = sshbuf_put_u8(arg, c);
break;
case '\\':
case '\'':
case '"':
if ((r = sshbuf_put_u8(arg, '\\')) != 0)
break;
/* FALLTHROUGH */
default:
r = sshbuf_put_u8(arg, c);
break;
}
if (r != 0)
fatal_fr(r, "sshbuf_put_u8");
}
if ((i != 0 && (r = sshbuf_put_u8(buf, ' ')) != 0) ||
(ws != 0 && (r = sshbuf_put_u8(buf, '"')) != 0) ||
(r = sshbuf_putb(buf, arg)) != 0 ||
(ws != 0 && (r = sshbuf_put_u8(buf, '"')) != 0))
fatal_fr(r, "assemble");
}
if ((ret = malloc(sshbuf_len(buf) + 1)) == NULL)
fatal_f("malloc failed");
memcpy(ret, sshbuf_ptr(buf), sshbuf_len(buf));
ret[sshbuf_len(buf)] = '\0';
sshbuf_free(buf);
sshbuf_free(arg);
return ret;
}
char *
argv_next(int *argcp, char ***argvp)
{
char *ret = (*argvp)[0];
if (*argcp > 0 && ret != NULL) {
(*argcp)--;
(*argvp)++;
}
return ret;
}
void
argv_consume(int *argcp)
{
*argcp = 0;
}
void
argv_free(char **av, int ac)
{
int i;
if (av == NULL)
return;
for (i = 0; i < ac; i++)
free(av[i]);
free(av);
}
/* Returns 0 if pid exited cleanly, non-zero otherwise */
int
exited_cleanly(pid_t pid, const char *tag, const char *cmd, int quiet)
{
int status;
while (waitpid(pid, &status, 0) == -1) {
if (errno != EINTR) {
error("%s waitpid: %s", tag, strerror(errno));
return -1;
}
}
if (WIFSIGNALED(status)) {
error("%s %s exited on signal %d", tag, cmd, WTERMSIG(status));
return -1;
} else if (WEXITSTATUS(status) != 0) {
do_log2(quiet ? SYSLOG_LEVEL_DEBUG1 : SYSLOG_LEVEL_INFO,
"%s %s failed, status %d", tag, cmd, WEXITSTATUS(status));
return -1;
}
return 0;
}
/*
* Check a given path for security. This is defined as all components
* of the path to the file must be owned by either the owner of
* of the file or root and no directories must be group or world writable.
*
* XXX Should any specific check be done for sym links ?
*
* Takes a file name, its stat information (preferably from fstat() to
* avoid races), the uid of the expected owner, their home directory and an
* error buffer plus max size as arguments.
*
* Returns 0 on success and -1 on failure
*/
int
safe_path(const char *name, struct stat *stp, const char *pw_dir,
uid_t uid, char *err, size_t errlen)
{
char buf[PATH_MAX], homedir[PATH_MAX];
char *cp;
int comparehome = 0;
struct stat st;
if (realpath(name, buf) == NULL) {
snprintf(err, errlen, "realpath %s failed: %s", name,
strerror(errno));
return -1;
}
if (pw_dir != NULL && realpath(pw_dir, homedir) != NULL)
comparehome = 1;
if (!S_ISREG(stp->st_mode)) {
snprintf(err, errlen, "%s is not a regular file", buf);
return -1;
}
if ((!platform_sys_dir_uid(stp->st_uid) && stp->st_uid != uid) ||
(stp->st_mode & 022) != 0) {
snprintf(err, errlen, "bad ownership or modes for file %s",
buf);
return -1;
}
/* for each component of the canonical path, walking upwards */
for (;;) {
if ((cp = dirname(buf)) == NULL) {
snprintf(err, errlen, "dirname() failed");
return -1;
}
strlcpy(buf, cp, sizeof(buf));
if (stat(buf, &st) == -1 ||
(!platform_sys_dir_uid(st.st_uid) && st.st_uid != uid) ||
(st.st_mode & 022) != 0) {
snprintf(err, errlen,
"bad ownership or modes for directory %s", buf);
return -1;
}
/* If are past the homedir then we can stop */
if (comparehome && strcmp(homedir, buf) == 0) // CodeQL [SM01714] false positive: homedir is null terminated
break;
/*
* dirname should always complete with a "/" path,
* but we can be paranoid and check for "." too
*/
if ((strcmp("/", buf) == 0) || (strcmp(".", buf) == 0))
break;
}
return 0;
}
/*
* Version of safe_path() that accepts an open file descriptor to
* avoid races.
*
* Returns 0 on success and -1 on failure
*/
int
safe_path_fd(int fd, const char *file, struct passwd *pw,
char *err, size_t errlen)
{
struct stat st;
/* check the open file to avoid races */
if (fstat(fd, &st) == -1) {
snprintf(err, errlen, "cannot stat file %s: %s",
file, strerror(errno));
return -1;
}
return safe_path(file, &st, pw->pw_dir, pw->pw_uid, err, errlen);
}
/*
* Sets the value of the given variable in the environment. If the variable
* already exists, its value is overridden.
*/
void
child_set_env(char ***envp, u_int *envsizep, const char *name,
const char *value)
{
char **env;
u_int envsize;
u_int i, namelen;
if (strchr(name, '=') != NULL) {
error("Invalid environment variable \"%.100s\"", name);
return;
}
/*
* If we're passed an uninitialized list, allocate a single null
* entry before continuing.
*/
if ((*envp == NULL) != (*envsizep == 0))
fatal_f("environment size mismatch");
if (*envp == NULL && *envsizep == 0) {
*envp = xmalloc(sizeof(char *));
*envp[0] = NULL;
*envsizep = 1;
}
/*
* Find the slot where the value should be stored. If the variable
* already exists, we reuse the slot; otherwise we append a new slot
* at the end of the array, expanding if necessary.
*/
env = *envp;
namelen = strlen(name);
for (i = 0; env[i]; i++)
if (strncmp(env[i], name, namelen) == 0 && env[i][namelen] == '=')
break;
if (env[i]) {
/* Reuse the slot. */
free(env[i]);
} else {
/* New variable. Expand if necessary. */
envsize = *envsizep;
if (i >= envsize - 1) {
if (envsize >= 1000)
fatal("child_set_env: too many env vars");
envsize += 50;
env = (*envp) = xreallocarray(env, envsize, sizeof(char *));
*envsizep = envsize;
}
/* Need to set the NULL pointer at end of array beyond the new slot. */
env[i + 1] = NULL;
}
/* Allocate space and format the variable in the appropriate slot. */
/* XXX xasprintf */
env[i] = xmalloc(strlen(name) + 1 + strlen(value) + 1);
snprintf(env[i], strlen(name) + 1 + strlen(value) + 1, "%s=%s", name, value);
}
/*
* Check and optionally lowercase a domain name, also removes trailing '.'
* Returns 1 on success and 0 on failure, storing an error message in errstr.
*/
int
valid_domain(char *name, int makelower, const char **errstr)
{
size_t i, l = strlen(name);
u_char c, last = '\0';
static char errbuf[256];
if (l == 0) {
strlcpy(errbuf, "empty domain name", sizeof(errbuf));
goto bad;
}
if (!isalpha((u_char)name[0]) && !isdigit((u_char)name[0])) {
snprintf(errbuf, sizeof(errbuf), "domain name \"%.100s\" "
"starts with invalid character", name);
goto bad;
}
for (i = 0; i < l; i++) {
c = tolower((u_char)name[i]);
if (makelower)
name[i] = (char)c;
if (last == '.' && c == '.') {
snprintf(errbuf, sizeof(errbuf), "domain name "
"\"%.100s\" contains consecutive separators", name);
goto bad;
}
if (c != '.' && c != '-' && !isalnum(c) &&
c != '_') /* technically invalid, but common */ {
snprintf(errbuf, sizeof(errbuf), "domain name "
"\"%.100s\" contains invalid characters", name);
goto bad;
}
last = c;
}
if (name[l - 1] == '.')
name[l - 1] = '\0';
if (errstr != NULL)
*errstr = NULL;
return 1;
bad:
if (errstr != NULL)
*errstr = errbuf;
return 0;
}
/*
* Verify that a environment variable name (not including initial '$') is
* valid; consisting of one or more alphanumeric or underscore characters only.
* Returns 1 on valid, 0 otherwise.
*/
int
valid_env_name(const char *name)
{
const char *cp;
if (name[0] == '\0')
return 0;
for (cp = name; *cp != '\0'; cp++) {
if (!isalnum((u_char)*cp) && *cp != '_')
return 0;
}
return 1;
}
const char *
atoi_err(const char *nptr, int *val)
{
const char *errstr = NULL;
if (nptr == NULL || *nptr == '\0')
return "missing";
*val = strtonum(nptr, 0, INT_MAX, &errstr);
return errstr;
}
int
parse_absolute_time(const char *s, uint64_t *tp)
{
struct tm tm;
time_t tt;
char buf[32], *fmt;
const char *cp;
size_t l;
int is_utc = 0;
*tp = 0;
l = strlen(s);
if (l > 1 && strcasecmp(s + l - 1, "Z") == 0) {
is_utc = 1;
l--;
} else if (l > 3 && strcasecmp(s + l - 3, "UTC") == 0) {
is_utc = 1;
l -= 3;
}
/*
* POSIX strptime says "The application shall ensure that there
* is white-space or other non-alphanumeric characters between
* any two conversion specifications" so arrange things this way.
*/
switch (l) {
case 8: /* YYYYMMDD */
fmt = "%Y-%m-%d";
snprintf(buf, sizeof(buf), "%.4s-%.2s-%.2s", s, s + 4, s + 6);
break;
case 12: /* YYYYMMDDHHMM */
fmt = "%Y-%m-%dT%H:%M";
snprintf(buf, sizeof(buf), "%.4s-%.2s-%.2sT%.2s:%.2s",
s, s + 4, s + 6, s + 8, s + 10);
break;
case 14: /* YYYYMMDDHHMMSS */
fmt = "%Y-%m-%dT%H:%M:%S";
snprintf(buf, sizeof(buf), "%.4s-%.2s-%.2sT%.2s:%.2s:%.2s",
s, s + 4, s + 6, s + 8, s + 10, s + 12);
break;
default:
return SSH_ERR_INVALID_FORMAT;
}
memset(&tm, 0, sizeof(tm));
if ((cp = strptime(buf, fmt, &tm)) == NULL || *cp != '\0')
return SSH_ERR_INVALID_FORMAT;
if (is_utc) {
if ((tt = timegm(&tm)) < 0)
return SSH_ERR_INVALID_FORMAT;
} else {
if ((tt = mktime(&tm)) < 0)
return SSH_ERR_INVALID_FORMAT;
}
/* success */
*tp = (uint64_t)tt;
return 0;
}
void
format_absolute_time(uint64_t t, char *buf, size_t len)
{
time_t tt = t > SSH_TIME_T_MAX ? SSH_TIME_T_MAX : t;
struct tm tm;
localtime_r(&tt, &tm);
strftime(buf, len, "%Y-%m-%dT%H:%M:%S", &tm);
}
/*
* Parse a "pattern=interval" clause (e.g. a ChannelTimeout).
* Returns 0 on success or non-zero on failure.
* Caller must free *typep.
*/
int
parse_pattern_interval(const char *s, char **typep, int *secsp)
{
char *cp, *sdup;
int secs;
if (typep != NULL)
*typep = NULL;
if (secsp != NULL)
*secsp = 0;
if (s == NULL)
return -1;
sdup = xstrdup(s);
if ((cp = strchr(sdup, '=')) == NULL || cp == sdup) {
free(sdup);
return -1;
}
*cp++ = '\0';
if ((secs = convtime(cp)) < 0) {
free(sdup);
return -1;
}
/* success */
if (typep != NULL)
*typep = xstrdup(sdup);
if (secsp != NULL)
*secsp = secs;
free(sdup);
return 0;
}
/* check if path is absolute */
int
path_absolute(const char *path)
{
#ifdef WINDOWS
return is_absolute_path(path);
#else
return (*path == '/') ? 1 : 0;
#endif
}
void
skip_space(char **cpp)
{
char *cp;
for (cp = *cpp; *cp == ' ' || *cp == '\t'; cp++)
;
*cpp = cp;
}
/* authorized_key-style options parsing helpers */
/*
* Match flag 'opt' in *optsp, and if allow_negate is set then also match
* 'no-opt'. Returns -1 if option not matched, 1 if option matches or 0
* if negated option matches.
* If the option or negated option matches, then *optsp is updated to
* point to the first character after the option.
*/
int
opt_flag(const char *opt, int allow_negate, const char **optsp)
{
size_t opt_len = strlen(opt);
const char *opts = *optsp;
int negate = 0;
if (allow_negate && strncasecmp(opts, "no-", 3) == 0) {
opts += 3;
negate = 1;
}
if (strncasecmp(opts, opt, opt_len) == 0) {
*optsp = opts + opt_len;
return negate ? 0 : 1;
}
return -1;
}
char *
opt_dequote(const char **sp, const char **errstrp)
{
const char *s = *sp;
char *ret;
size_t i;
*errstrp = NULL;
if (*s != '"') {
*errstrp = "missing start quote";
return NULL;
}
s++;
if ((ret = malloc(strlen((s)) + 1)) == NULL) {
*errstrp = "memory allocation failed";
return NULL;
}
for (i = 0; *s != '\0' && *s != '"';) {
if (s[0] == '\\' && s[1] == '"')
s++;
ret[i++] = *s++;
}
if (*s == '\0') {
*errstrp = "missing end quote";
free(ret);
return NULL;
}
ret[i] = '\0';
s++;
*sp = s;
return ret;
}
int
opt_match(const char **opts, const char *term)
{
if (strncasecmp((*opts), term, strlen(term)) == 0 &&
(*opts)[strlen(term)] == '=') {
*opts += strlen(term) + 1;
return 1;
}
return 0;
}
void
opt_array_append2(const char *file, const int line, const char *directive,
char ***array, int **iarray, u_int *lp, const char *s, int i)
{
if (*lp >= INT_MAX)
fatal("%s line %d: Too many %s entries", file, line, directive);
if (iarray != NULL) {
*iarray = xrecallocarray(*iarray, *lp, *lp + 1,
sizeof(**iarray));
(*iarray)[*lp] = i;
}
*array = xrecallocarray(*array, *lp, *lp + 1, sizeof(**array));
(*array)[*lp] = xstrdup(s);
(*lp)++;
}
void
opt_array_append(const char *file, const int line, const char *directive,
char ***array, u_int *lp, const char *s)
{
opt_array_append2(file, line, directive, array, NULL, lp, s, 0);
}
void
opt_array_free2(char **array, int **iarray, u_int l)
{
u_int i;
if (array == NULL || l == 0)
return;
for (i = 0; i < l; i++)
free(array[i]);
free(array);
free(iarray);
}
sshsig_t
ssh_signal(int signum, sshsig_t handler)
{
#ifdef WINDOWS
return signal(signum, handler);
#else
struct sigaction sa, osa;
/* mask all other signals while in handler */
memset(&sa, 0, sizeof(sa));
sa.sa_handler = handler;
sigfillset(&sa.sa_mask);
#if defined(SA_RESTART) && !defined(NO_SA_RESTART)
if (signum != SIGALRM)
sa.sa_flags = SA_RESTART;
#endif
if (sigaction(signum, &sa, &osa) == -1) {
debug3("sigaction(%s): %s", strsignal(signum), strerror(errno));
return SIG_ERR;
}
return osa.sa_handler;
#endif // WINDOWS
}
int
stdfd_devnull(int do_stdin, int do_stdout, int do_stderr)
{
int devnull, ret = 0;
if ((devnull = open(_PATH_DEVNULL, O_RDWR)) == -1) {
error_f("open %s: %s", _PATH_DEVNULL,
strerror(errno));
return -1;
}
if ((do_stdin && dup2(devnull, STDIN_FILENO) == -1) ||
(do_stdout && dup2(devnull, STDOUT_FILENO) == -1) ||
(do_stderr && dup2(devnull, STDERR_FILENO) == -1)) {
error_f("dup2: %s", strerror(errno));
ret = -1;
}
if (devnull > STDERR_FILENO)
close(devnull);
return ret;
}
/*
* Runs command in a subprocess with a minimal environment.
* Returns pid on success, 0 on failure.
* The child stdout and stderr maybe captured, left attached or sent to
* /dev/null depending on the contents of flags.
* "tag" is prepended to log messages.
* NB. "command" is only used for logging; the actual command executed is
* av[0].
*/
pid_t
subprocess(const char *tag, const char *command,
int ac, char **av, FILE **child, u_int flags,
struct passwd *pw, privdrop_fn *drop_privs, privrestore_fn *restore_privs)
{
FILE *f = NULL;
struct stat st;
int fd, devnull, p[2], i;
pid_t pid;
char *cp, errmsg[512];
u_int nenv = 0;
char **env = NULL;
/* If dropping privs, then must specify user and restore function */
if (drop_privs != NULL && (pw == NULL || restore_privs == NULL)) {
error("%s: inconsistent arguments", tag); /* XXX fatal? */
return 0;
}
if (pw == NULL && (pw = getpwuid(getuid())) == NULL) {
error("%s: no user for current uid", tag);
return 0;
}
if (child != NULL)
*child = NULL;
debug3_f("%s command \"%s\" running as %s (flags 0x%x)",
tag, command, pw->pw_name, flags);
/* Check consistency */
if ((flags & SSH_SUBPROCESS_STDOUT_DISCARD) != 0 &&
(flags & SSH_SUBPROCESS_STDOUT_CAPTURE) != 0) {
error_f("inconsistent flags");
return 0;
}
if (((flags & SSH_SUBPROCESS_STDOUT_CAPTURE) == 0) != (child == NULL)) {
error_f("inconsistent flags/output");
return 0;
}
/*
* If executing an explicit binary, then verify the it exists
* and appears safe-ish to execute
*/
if (!path_absolute(av[0])) {
error("%s path is not absolute", tag);
return 0;
}
if (drop_privs != NULL)
drop_privs(pw);
if (stat(av[0], &st) == -1) {
error("Could not stat %s \"%s\": %s", tag,
av[0], strerror(errno));
goto restore_return;
}
if ((flags & SSH_SUBPROCESS_UNSAFE_PATH) == 0 &&
#ifdef WINDOWS
(check_secure_file_permission(av[0], pw, 1) != 0)) {
error("Permissions on %s:\"%s\" are too open", tag, av[0]);
#else
safe_path(av[0], &st, NULL, 0, errmsg, sizeof(errmsg)) != 0) {
error("Unsafe %s \"%s\": %s", tag, av[0], errmsg);
#endif
goto restore_return;
}
/* Prepare to keep the child's stdout if requested */
if (pipe(p) == -1) {
error("%s: pipe: %s", tag, strerror(errno));
restore_return:
if (restore_privs != NULL)
restore_privs();
return 0;
}
if (restore_privs != NULL)
restore_privs();
#ifdef FORK_NOT_SUPPORTED
{
posix_spawn_file_actions_t actions;
pid = -1;
if (posix_spawn_file_actions_init(&actions) != 0 ||
posix_spawn_file_actions_adddup2(&actions, p[1], STDOUT_FILENO) != 0)
fatal("posix_spawn initialization failed");
else {
#ifdef WINDOWS
extern PSID get_sid(const char*);
/* If the user's SID is the System SID and sshd is running as system,
* launch as a child process.
*/
if (IsWellKnownSid(get_sid(pw->pw_name), WinLocalSystemSid) && am_system()) {
debug("starting subprocess using posix_spawnp");
if (posix_spawnp((pid_t*)&pid, av[0], &actions, NULL, av, NULL) != 0)
fatal("posix_spawnp: %s", strerror(errno));
}
else
#endif
{
debug("starting subprocess as user using __posix_spawn_asuser");
if (__posix_spawn_asuser((pid_t*)&pid, av[0], &actions, NULL, av, NULL, pw->pw_name) != 0)
fatal("posix_spawn_user: %s", strerror(errno));
}
}
posix_spawn_file_actions_destroy(&actions);
}
#else
switch ((pid = fork())) {
case -1: /* error */
error("%s: fork: %s", tag, strerror(errno));
close(p[0]);
close(p[1]);
return 0;
case 0: /* child */
/* Prepare a minimal environment for the child. */
if ((flags & SSH_SUBPROCESS_PRESERVE_ENV) == 0) {
nenv = 5;
env = xcalloc(sizeof(*env), nenv);
child_set_env(&env, &nenv, "PATH", _PATH_STDPATH);
child_set_env(&env, &nenv, "USER", pw->pw_name);
child_set_env(&env, &nenv, "LOGNAME", pw->pw_name);
child_set_env(&env, &nenv, "HOME", pw->pw_dir);
if ((cp = getenv("LANG")) != NULL)
child_set_env(&env, &nenv, "LANG", cp);
}
for (i = 1; i < NSIG; i++)
ssh_signal(i, SIG_DFL);
if ((devnull = open(_PATH_DEVNULL, O_RDWR)) == -1) {
error("%s: open %s: %s", tag, _PATH_DEVNULL,
strerror(errno));
_exit(1);
}
if (dup2(devnull, STDIN_FILENO) == -1) {
error("%s: dup2: %s", tag, strerror(errno));
_exit(1);
}
/* Set up stdout as requested; leave stderr in place for now. */
fd = -1;
if ((flags & SSH_SUBPROCESS_STDOUT_CAPTURE) != 0)
fd = p[1];
else if ((flags & SSH_SUBPROCESS_STDOUT_DISCARD) != 0)
fd = devnull;
if (fd != -1 && dup2(fd, STDOUT_FILENO) == -1) {
error("%s: dup2: %s", tag, strerror(errno));
_exit(1);
}
closefrom(STDERR_FILENO + 1);
if (geteuid() == 0 &&
initgroups(pw->pw_name, pw->pw_gid) == -1) {
error("%s: initgroups(%s, %u): %s", tag,
pw->pw_name, (u_int)pw->pw_gid, strerror(errno));
_exit(1);
}
if (setresgid(pw->pw_gid, pw->pw_gid, pw->pw_gid) == -1) {
error("%s: setresgid %u: %s", tag, (u_int)pw->pw_gid,
strerror(errno));
_exit(1);
}
if (setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid) == -1) {
error("%s: setresuid %u: %s", tag, (u_int)pw->pw_uid,
strerror(errno));
_exit(1);
}
/* stdin is pointed to /dev/null at this point */
if ((flags & SSH_SUBPROCESS_STDOUT_DISCARD) != 0 &&
dup2(STDIN_FILENO, STDERR_FILENO) == -1) {
error("%s: dup2: %s", tag, strerror(errno));
_exit(1);
}
if (env != NULL)
execve(av[0], av, env);
else
execv(av[0], av);
error("%s %s \"%s\": %s", tag, env == NULL ? "execv" : "execve",
command, strerror(errno));
_exit(127);
default: /* parent */
break;
}
#endif
close(p[1]);
if ((flags & SSH_SUBPROCESS_STDOUT_CAPTURE) == 0)
close(p[0]);
else if ((f = fdopen(p[0], "r")) == NULL) {
error("%s: fdopen: %s", tag, strerror(errno));
close(p[0]);
/* Don't leave zombie child */
kill(pid, SIGTERM);
while (waitpid(pid, NULL, 0) == -1 && errno == EINTR)
;
return 0;
}
/* Success */
debug3_f("%s pid %ld", tag, (long)pid);
if (child != NULL)
*child = f;
return pid;
}
const char *
lookup_env_in_list(const char *env, char * const *envs, size_t nenvs)
{
size_t i, envlen;
envlen = strlen(env);
for (i = 0; i < nenvs; i++) {
if (strncmp(envs[i], env, envlen) == 0 &&
envs[i][envlen] == '=') {
return envs[i] + envlen + 1;
}
}
return NULL;
}
const char *
lookup_setenv_in_list(const char *env, char * const *envs, size_t nenvs)
{
char *name, *cp;
const char *ret;
name = xstrdup(env);
if ((cp = strchr(name, '=')) == NULL) {
free(name);
return NULL; /* not env=val */
}
*cp = '\0';
ret = lookup_env_in_list(name, envs, nenvs);
free(name);
return ret;
}
/*
* Helpers for managing poll(2)/ppoll(2) timeouts
* Will remember the earliest deadline and return it for use in poll/ppoll.
*/
/* Initialise a poll/ppoll timeout with an indefinite deadline */
void
ptimeout_init(struct timespec *pt)
{
/*
* Deliberately invalid for ppoll(2).
* Will be converted to NULL in ptimeout_get_tspec() later.
*/
pt->tv_sec = -1;
pt->tv_nsec = 0;
}
/* Specify a poll/ppoll deadline of at most 'sec' seconds */
void
ptimeout_deadline_sec(struct timespec *pt, long sec)
{
if (pt->tv_sec == -1 || pt->tv_sec >= sec) {
pt->tv_sec = sec;
pt->tv_nsec = 0;
}
}
/* Specify a poll/ppoll deadline of at most 'p' (timespec) */
static void
ptimeout_deadline_tsp(struct timespec *pt, struct timespec *p)
{
if (pt->tv_sec == -1 || timespeccmp(pt, p, >=))
*pt = *p;
}
/* Specify a poll/ppoll deadline of at most 'ms' milliseconds */
void
ptimeout_deadline_ms(struct timespec *pt, long ms)
{
struct timespec p;
p.tv_sec = ms / 1000;
p.tv_nsec = (ms % 1000) * 1000000;
ptimeout_deadline_tsp(pt, &p);
}
/* Specify a poll/ppoll deadline at wall clock monotime 'when' (timespec) */
void
ptimeout_deadline_monotime_tsp(struct timespec *pt, struct timespec *when)
{
struct timespec now, t;
monotime_ts(&now);
if (timespeccmp(&now, when, >=)) {
/* 'when' is now or in the past. Timeout ASAP */
pt->tv_sec = 0;
pt->tv_nsec = 0;
} else {
timespecsub(when, &now, &t);
ptimeout_deadline_tsp(pt, &t);
}
}
/* Specify a poll/ppoll deadline at wall clock monotime 'when' */
void
ptimeout_deadline_monotime(struct timespec *pt, time_t when)
{
struct timespec t;
t.tv_sec = when;
t.tv_nsec = 0;
ptimeout_deadline_monotime_tsp(pt, &t);
}
/* Get a poll(2) timeout value in milliseconds */
int
ptimeout_get_ms(struct timespec *pt)
{
if (pt->tv_sec == -1)
return -1;
if (pt->tv_sec >= (INT_MAX - (pt->tv_nsec / 1000000)) / 1000)
return INT_MAX;
return (pt->tv_sec * 1000) + (pt->tv_nsec / 1000000);
}
/* Get a ppoll(2) timeout value as a timespec pointer */
struct timespec *
ptimeout_get_tsp(struct timespec *pt)
{
return pt->tv_sec == -1 ? NULL : pt;
}
/* Returns non-zero if a timeout has been set (i.e. is not indefinite) */
int
ptimeout_isset(struct timespec *pt)
{
return pt->tv_sec != -1;
}
/*
* Returns zero if the library at 'path' contains symbol 's', nonzero
* otherwise.
*/
int
lib_contains_symbol(const char *path, const char *s)
{
#ifndef WINDOWS
#ifdef HAVE_NLIST_H
struct nlist nl[2];
int ret = -1, r;
memset(nl, 0, sizeof(nl));
nl[0].n_name = xstrdup(s);
nl[1].n_name = NULL;
if ((r = nlist(path, nl)) == -1) {
error_f("nlist failed for %s", path);
goto out;
}
if (r != 0 || nl[0].n_value == 0 || nl[0].n_type == 0) {
error_f("library %s does not contain symbol %s", path, s);
goto out;
}
/* success */
ret = 0;
out:
free(nl[0].n_name);
return ret;
#else /* HAVE_NLIST_H */
int fd, ret = -1;
struct stat st;
void *m = NULL;
size_t sz = 0;
memset(&st, 0, sizeof(st));
if ((fd = open(path, O_RDONLY)) < 0) {
error_f("open %s: %s", path, strerror(errno));
return -1;
}
if (fstat(fd, &st) != 0) {
error_f("fstat %s: %s", path, strerror(errno));
goto out;
}
if (!S_ISREG(st.st_mode)) {
error_f("%s is not a regular file", path);
goto out;
}
if (st.st_size < 0 ||
(size_t)st.st_size < strlen(s) ||
st.st_size >= INT_MAX/2) {
error_f("%s bad size %lld", path, (long long)st.st_size);
goto out;
}
sz = (size_t)st.st_size;
if ((m = mmap(NULL, sz, PROT_READ, MAP_PRIVATE, fd, 0)) == MAP_FAILED ||
m == NULL) {
error_f("mmap %s: %s", path, strerror(errno));
goto out;
}
if (memmem(m, sz, s, strlen(s)) == NULL) {
error_f("%s does not contain expected string %s", path, s);
goto out;
}
/* success */
ret = 0;
out:
if (m != NULL && m != MAP_FAILED)
munmap(m, sz);
close(fd);
return ret;
#endif /* HAVE_NLIST_H */
#else /* WINDOWS */
return 0;
#endif /* WINDOWS */
}
int
signal_is_crash(int sig)
{
switch (sig) {
case SIGSEGV:
case SIGBUS:
case SIGTRAP:
case SIGSYS:
case SIGFPE:
case SIGILL:
case SIGABRT:
return 1;
}
return 0;
}
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