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openssh/misc.c
djm@openbsd.org fd4eeeec16 upstream commit 
fix ordering in previous to ensure errno isn't clobbered
before logging.

OpenBSD-Commit-ID: e260bc1e145a9690dcb0d5aa9460c7b96a0c8ab2
2017-12-12 10:32:04 +11:00

2130 lines
46 KiB
C
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/* $OpenBSD: misc.c,v 1.122 2017/12/08 02:14:33 djm Exp $ */
/*
* Copyright (c) 2000 Markus Friedl. All rights reserved.
* Copyright (c) 2005,2006 Damien Miller. 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.
*/
#include "includes.h"
#include <sys/types.h>
#include <sys/ioctl.h>
#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
#include <signal.h>
#include <stdarg.h>
#include <stdio.h>
#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 <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <netdb.h>
#ifdef HAVE_PATHS_H
# include <paths.h>
#include <pwd.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 "uidswap.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;
}
/* set/unset filedescriptor to non-blocking */
int
set_nonblock(int fd)
{
int val;
val = fcntl(fd, F_GETFL);
if (val < 0) {
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 < 0) {
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
}
/* Characters considered whitespace in strsep calls. */
#define WHITESPACE " \t\r\n"
#define QUOTE "\""
/* return next token in configuration line */
char *
strdelim(char **s)
{
char *old;
int wspace = 0;
if (*s == NULL)
return NULL;
old = *s;
*s = strpbrk(*s, 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 (*s[0] == '=')
wspace = 1;
*s[0] = '\0';
/* Skip any extra whitespace after first token */
*s += strspn(*s + 1, WHITESPACE) + 1;
if (*s[0] == '=' && !wspace)
*s += strspn(*s + 1, WHITESPACE) + 1;
return (old);
}
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);
#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)
{
long long port;
const char *errstr;
port = strtonum(s, 0, 65535, &errstr);
if (errstr != NULL)
return -1;
return (int)port;
}
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)
/*
* 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.
*/
long
convtime(const char *s)
{
long total, secs, multiplier = 1;
const char *p;
char *endp;
errno = 0;
total = 0;
p = s;
if (p == NULL || *p == '\0')
return -1;
while (*p) {
secs = strtol(p, &endp, 10);
if (p == endp ||
(errno == ERANGE && (secs == LONG_MIN || secs == LONG_MAX)) ||
secs < 0)
return -1;
switch (*endp++) {
case '\0':
endp--;
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:
return -1;
}
if (secs >= LONG_MAX / multiplier)
return -1;
secs *= multiplier;
if (total >= LONG_MAX - secs)
return -1;
total += secs;
if (total < 0)
return -1;
p = endp;
}
return total;
}
/*
* 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) < 0)
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.
*/
static 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;
}
char *
hpdelim(char **cp)
{
return hpdelim2(cp, NULL);
}
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;
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;
ret = xmalloc(strlen(src) + 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;
*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("addargs: argument too long");
nalloc = args->nalloc;
if (args->list == NULL) {
nalloc = 32;
args->num = 0;
} 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("replacearg: argument too long");
if (which >= args->num)
fatal("replacearg: 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->list != NULL) {
for (i = 0; i < args->num; i++)
free(args->list[i]);
free(args->list);
args->nalloc = args->num = 0;
args->list = NULL;
}
}
/*
* Expands tildes in the file name. Returns data allocated by xmalloc.
* Warning: this calls getpw*.
*/
char *
tilde_expand_filename(const char *filename, uid_t uid)
{
const char *path, *sep;
char user[128], *ret;
struct passwd *pw;
u_int len, slash;
if (*filename != '~')
return (xstrdup(filename));
filename++;
path = strchr(filename, '/');
if (path != NULL && path > filename) { /* ~user/path */
slash = path - filename;
if (slash > sizeof(user) - 1)
fatal("tilde_expand_filename: ~username too long");
memcpy(user, filename, slash);
user[slash] = '\0';
if ((pw = getpwnam(user)) == NULL)
fatal("tilde_expand_filename: No such user %s", user);
} else if ((pw = getpwuid(uid)) == NULL) /* ~/path */
fatal("tilde_expand_filename: No such uid %ld", (long)uid);
/* Make sure directory has a trailing '/' */
len = strlen(pw->pw_dir);
if (len == 0 || pw->pw_dir[len - 1] != '/')
sep = "/";
else
sep = "";
/* Skip leading '/' from specified path */
if (path != NULL)
filename = path + 1;
if (xasprintf(&ret, "%s%s%s", pw->pw_dir, sep, filename) >= PATH_MAX)
fatal("tilde_expand_filename: Path too long");
return (ret);
}
/*
* Expand a string with a set of %[char] escapes. 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.
*/
char *
percent_expand(const char *string, ...)
{
#define EXPAND_MAX_KEYS 16
u_int num_keys, i, j;
struct {
const char *key;
const char *repl;
} keys[EXPAND_MAX_KEYS];
char buf[4096];
va_list ap;
/* Gather keys */
va_start(ap, string);
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("%s: NULL replacement", __func__);
}
if (num_keys == EXPAND_MAX_KEYS && va_arg(ap, char *) != NULL)
fatal("%s: too many keys", __func__);
va_end(ap);
/* Expand string */
*buf = '\0';
for (i = 0; *string != '\0'; string++) {
if (*string != '%') {
append:
buf[i++] = *string;
if (i >= sizeof(buf))
fatal("%s: string too long", __func__);
buf[i] = '\0';
continue;
}
string++;
/* %% case */
if (*string == '%')
goto append;
if (*string == '\0')
fatal("%s: invalid format", __func__);
for (j = 0; j < num_keys; j++) {
if (strchr(keys[j].key, *string) != NULL) {
i = strlcat(buf, keys[j].repl, sizeof(buf));
if (i >= sizeof(buf))
fatal("%s: string too long", __func__);
break;
}
}
if (j >= num_keys)
fatal("%s: unknown key %%%c", __func__, *string);
}
return (xstrdup(buf));
#undef EXPAND_MAX_KEYS
}
/*
* Read an entire line from a public key file into a static buffer, discarding
* lines that exceed the buffer size. Returns 0 on success, -1 on failure.
*/
int
read_keyfile_line(FILE *f, const char *filename, char *buf, size_t bufsz,
u_long *lineno)
{
while (fgets(buf, bufsz, f) != NULL) {
if (buf[0] == '\0')
continue;
(*lineno)++;
if (buf[strlen(buf) - 1] == '\n' || feof(f)) {
return 0;
} else {
debug("%s: %s line %lu exceeds size limit", __func__,
filename, *lineno);
/* discard remainder of line */
while (fgetc(f) != '\n' && !feof(f))
; /* nothing */
}
}
return -1;
}
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("%s: invalid tunnel %u", __func__, tun);
return -1;
}
if (fd < 0) {
debug("%s: %s open: %s", __func__, name, strerror(errno));
return -1;
}
debug("%s: %s mode %d fd %d", __func__, 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("%s: get interface %s flags: %s", __func__,
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("%s: activate interface %s: %s", __func__,
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);
}
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_timeval(struct timeval *tv, int ms)
{
if (ms < 0)
ms = 0;
tv->tv_sec = ms / 1000;
tv->tv_usec = (ms % 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 = bw->rate;
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;
if (!timerisset(&bw->bwstart)) {
monotime_tv(&bw->bwstart);
return;
}
bw->lamt += read_len;
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;
if ((tmpdir = getenv("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("%s: template string too short", __func__);
}
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 },
{ "lowdelay", IPTOS_LOWDELAY },
{ "throughput", IPTOS_THROUGHPUT },
{ "reliability", IPTOS_RELIABILITY },
{ NULL, -1 }
};
int
parse_ipqos(const char *cp)
{
u_int i;
char *ep;
long 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 = strtol(cp, &ep, 0);
if (*cp == '\0' || *ep != '\0' || val < 0 || val > 255)
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("%s: path \"%s\" too long for Unix domain socket",
__func__, path);
errno = ENAMETOOLONG;
return -1;
}
sock = socket(PF_UNIX, SOCK_STREAM, 0);
if (sock < 0) {
saved_errno = errno;
error("%s: socket: %.100s", __func__, 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)) < 0) {
saved_errno = errno;
error("%s: cannot bind to path %s: %s",
__func__, path, strerror(errno));
close(sock);
errno = saved_errno;
return -1;
}
if (listen(sock, backlog) < 0) {
saved_errno = errno;
error("%s: cannot listen on path %s: %s",
__func__, 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 1 if bind to specified port by specified user is permitted */
int
bind_permitted(int port, uid_t uid)
{
if (port < IPPORT_RESERVED && uid != 0)
return 0;
return 1;
}
/* returns 1 if process is already daemonized, 0 otherwise */
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;
}
/*
* 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 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;
/* Start of a token */
quote = 0;
if (s[i] == '\\' &&
(s[i + 1] == '\'' || s[i + 1] == '\"' || s[i + 1] == '\\'))
i++;
else if (s[i] == '\'' || s[i] == '"')
quote = s[i++];
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] == '\\') {
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] == quote)
break; /* done */
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("%s: sshbuf_new failed", __func__);
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("%s: sshbuf_put_u8: %s",
__func__, ssh_err(r));
}
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("%s: buffer error: %s", __func__, ssh_err(r));
}
if ((ret = malloc(sshbuf_len(buf) + 1)) == NULL)
fatal("%s: malloc failed", __func__);
memcpy(ret, sshbuf_ptr(buf), sshbuf_len(buf));
ret[sshbuf_len(buf)] = '\0';
sshbuf_free(buf);
sshbuf_free(arg);
return ret;
}
/*
* Runs command in a subprocess wuth 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, struct passwd *pw, const char *command,
int ac, char **av, FILE **child, u_int flags)
{
FILE *f = NULL;
struct stat st;
int fd, devnull, p[2], i;
pid_t pid;
char *cp, errmsg[512];
u_int envsize;
char **child_env;
if (child != NULL)
*child = NULL;
debug3("%s: %s command \"%s\" running as %s (flags 0x%x)", __func__,
tag, command, pw->pw_name, flags);
/* Check consistency */
if ((flags & SSH_SUBPROCESS_STDOUT_DISCARD) != 0 &&
(flags & SSH_SUBPROCESS_STDOUT_CAPTURE) != 0) {
error("%s: inconsistent flags", __func__);
return 0;
}
if (((flags & SSH_SUBPROCESS_STDOUT_CAPTURE) == 0) != (child == NULL)) {
error("%s: inconsistent flags/output", __func__);
return 0;
}
/*
* If executing an explicit binary, then verify the it exists
* and appears safe-ish to execute
*/
if (*av[0] != '/') {
error("%s path is not absolute", tag);
return 0;
}
temporarily_use_uid(pw);
if (stat(av[0], &st) < 0) {
error("Could not stat %s \"%s\": %s", tag,
av[0], strerror(errno));
restore_uid();
return 0;
}
if (safe_path(av[0], &st, NULL, 0, errmsg, sizeof(errmsg)) != 0) {
error("Unsafe %s \"%s\": %s", tag, av[0], errmsg);
restore_uid();
return 0;
}
/* Prepare to keep the child's stdout if requested */
if (pipe(p) != 0) {
error("%s: pipe: %s", tag, strerror(errno));
restore_uid();
return 0;
}
restore_uid();
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. */
envsize = 5;
child_env = xcalloc(sizeof(*child_env), envsize);
child_set_env(&child_env, &envsize, "PATH", _PATH_STDPATH);
child_set_env(&child_env, &envsize, "USER", pw->pw_name);
child_set_env(&child_env, &envsize, "LOGNAME", pw->pw_name);
child_set_env(&child_env, &envsize, "HOME", pw->pw_dir);
if ((cp = getenv("LANG")) != NULL)
child_set_env(&child_env, &envsize, "LANG", cp);
for (i = 0; i < NSIG; i++)
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);
/* Don't use permanently_set_uid() here to avoid fatal() */
if (setresgid(pw->pw_gid, pw->pw_gid, pw->pw_gid) != 0) {
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) != 0) {
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);
}
execve(av[0], av, child_env);
error("%s exec \"%s\": %s", tag, command, strerror(errno));
_exit(127);
default: /* parent */
break;
}
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("%s: %s pid %ld", __func__, tag, (long)pid);
if (child != NULL)
*child = f;
return pid;
}
/* 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) < 0 ||
(!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)
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) < 0) {
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) {
*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. */
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;
}
const char *
atoi_err(const char *nptr, int *val)
{
const char *errstr = NULL;
long long num;
if (nptr == NULL || *nptr == '\0')
return "missing";
num = strtonum(nptr, 0, INT_MAX, &errstr);
if (errstr == NULL)
*val = (int)num;
return errstr;
}
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