Merge changes I934c73d4,I28cdc9a0,I9e734da9,I3c079d86

* changes:
  UPSTREAM: depend
  UPSTREAM: upstream: avoid possible NULL deref; from Pedro Martelletto
  Revert "upstream: fix compilation with DEBUG_KEXDH; bz#3160 ok dtucker@"
  Merge upstream-master into master

1 files changed, 1292 insertions, 134 deletions

diff --git a/misc.c b/misc.c
index d208b446..48ff6af8 100644
--- a/misc.c
+++ b/misc.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: misc.c,v 1.96 2015/01/16 06:40:12 deraadt Exp $ */
+/* $OpenBSD: misc.c,v 1.147 2020/04/25 06:59:36 dtucker Exp $ */
 /*
  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
  * Copyright (c) 2005,2006 Damien Miller.  All rights reserved.
@@ -29,9 +29,19 @@
 #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
+#ifdef HAVE_POLL_H
+#include <poll.h>
+#endif
+#include <signal.h>
 #include <stdarg.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -43,6 +53,7 @@
 #include <netinet/in_systm.h>
 #include <netinet/ip.h>
 #include <netinet/tcp.h>
+#include <arpa/inet.h>
 
 #include <ctype.h>
 #include <errno.h>
@@ -60,6 +71,9 @@
 #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 *
@@ -83,9 +97,9 @@ set_nonblock(int fd)
 {
 	int val;
 
-	val = fcntl(fd, F_GETFL, 0);
-	if (val < 0) {
-		error("fcntl(%d, F_GETFL, 0): %s", fd, strerror(errno));
+	val = fcntl(fd, F_GETFL);
+	if (val == -1) {
+		error("fcntl(%d, F_GETFL): %s", fd, strerror(errno));
 		return (-1);
 	}
 	if (val & O_NONBLOCK) {
@@ -107,9 +121,9 @@ unset_nonblock(int fd)
 {
 	int val;
 
-	val = fcntl(fd, F_GETFL, 0);
-	if (val < 0) {
-		error("fcntl(%d, F_GETFL, 0): %s", fd, strerror(errno));
+	val = fcntl(fd, F_GETFL);
+	if (val == -1) {
+		error("fcntl(%d, F_GETFL): %s", fd, strerror(errno));
 		return (-1);
 	}
 	if (!(val & O_NONBLOCK)) {
@@ -156,13 +170,164 @@ set_nodelay(int fd)
 		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
+}
+
+/*
+ * 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)
+{
+	struct pollfd pfd;
+	struct timeval t_start;
+	int oerrno, r;
+
+	monotime_tv(&t_start);
+	pfd.fd = fd;
+	pfd.events = events;
+	for (; *timeoutp >= 0;) {
+		r = poll(&pfd, 1, *timeoutp);
+		oerrno = errno;
+		ms_subtract_diff(&t_start, timeoutp);
+		errno = oerrno;
+		if (r > 0)
+			return 0;
+		else if (r == -1 && errno != EAGAIN)
+			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) {
+	return waitfd(fd, timeoutp, POLLIN);
+}
+
+/*
+ * 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);
+	if (connect(sockfd, serv_addr, addrlen) == 0) {
+		/* Succeeded already? */
+		unset_nonblock(sockfd);
+		return 0;
+	} else if (errno != EINPROGRESS)
+		return -1;
+
+	if (waitfd(sockfd, timeoutp, POLLIN | POLLOUT) == -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 */
-char *
-strdelim(char **s)
+static char *
+strdelim_internal(char **s, int split_equals)
 {
 	char *old;
 	int wspace = 0;
@@ -172,7 +337,8 @@ strdelim(char **s)
 
 	old = *s;
 
-	*s = strpbrk(*s, WHITESPACE QUOTE "=");
+	*s = strpbrk(*s,
+	    split_equals ? WHITESPACE QUOTE "=" : WHITESPACE QUOTE);
 	if (*s == NULL)
 		return (old);
 
@@ -189,18 +355,37 @@ strdelim(char **s)
 	}
 
 	/* Allow only one '=' to be skipped */
-	if (*s[0] == '=')
+	if (split_equals && *s[0] == '=')
 		wspace = 1;
 	*s[0] = '\0';
 
 	/* Skip any extra whitespace after first token */
 	*s += strspn(*s + 1, WHITESPACE) + 1;
-	if (*s[0] == '=' && !wspace)
+	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)
 {
@@ -235,13 +420,16 @@ pwcopy(struct passwd *pw)
 int
 a2port(const char *s)
 {
+	struct servent *se;
 	long long port;
 	const char *errstr;
 
 	port = strtonum(s, 0, 65535, &errstr);
-	if (errstr != NULL)
-		return -1;
-	return (int)port;
+	if (errstr == NULL)
+		return (int)port;
+	if ((se = getservbyname(s, "tcp")) != NULL)
+		return ntohs(se->s_port);
+	return -1;
 }
 
 int
@@ -305,7 +493,7 @@ a2tun(const char *s, int *remote)
 long
 convtime(const char *s)
 {
-	long total, secs;
+	long total, secs, multiplier = 1;
 	const char *p;
 	char *endp;
 
@@ -332,23 +520,28 @@ convtime(const char *s)
 			break;
 		case 'm':
 		case 'M':
-			secs *= MINUTES;
+			multiplier = MINUTES;
 			break;
 		case 'h':
 		case 'H':
-			secs *= HOURS;
+			multiplier = HOURS;
 			break;
 		case 'd':
 		case 'D':
-			secs *= DAYS;
+			multiplier = DAYS;
 			break;
 		case 'w':
 		case 'W':
-			secs *= WEEKS;
+			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;
@@ -369,7 +562,7 @@ put_host_port(const char *host, u_short port)
 
 	if (port == 0 || port == SSH_DEFAULT_PORT)
 		return(xstrdup(host));
-	if (asprintf(&hoststr, "[%s]:%d", host, (int)port) < 0)
+	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;
@@ -379,11 +572,12 @@ put_host_port(const char *host, u_short port)
  * 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 delimiter, if one was found.
+ * *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 *
-hpdelim(char **cp)
+hpdelim2(char **cp, char *delim)
 {
 	char *s, *old;
 
@@ -406,6 +600,8 @@ hpdelim(char **cp)
 
 	case ':':
 	case '/':
+		if (delim != NULL)
+			*delim = *s;
 		*s = '\0';	/* terminate */
 		*cp = s + 1;
 		break;
@@ -418,6 +614,12 @@ hpdelim(char **cp)
 }
 
 char *
+hpdelim(char **cp)
+{
+	return hpdelim2(cp, NULL);
+}
+
+char *
 cleanhostname(char *host)
 {
 	if (*host == '[' && host[strlen(host) - 1] == ']') {
@@ -450,6 +652,298 @@ colon(char *cp)
 	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, ...)
@@ -472,7 +966,7 @@ addargs(arglist *args, char *fmt, ...)
 	} else if (args->num+2 >= nalloc)
 		nalloc *= 2;
 
-	args->list = xrealloc(args->list, nalloc, sizeof(char *));
+	args->list = xrecallocarray(args->list, args->nalloc, nalloc, sizeof(char *));
 	args->nalloc = nalloc;
 	args->list[args->num++] = cp;
 	args->list[args->num] = NULL;
@@ -567,13 +1061,18 @@ char *
 percent_expand(const char *string, ...)
 {
 #define EXPAND_MAX_KEYS	16
-	u_int num_keys, i, j;
+	u_int num_keys, i;
 	struct {
 		const char *key;
 		const char *repl;
 	} keys[EXPAND_MAX_KEYS];
-	char buf[4096];
+	struct sshbuf *buf;
 	va_list ap;
+	int r;
+	char *ret;
+
+	if ((buf = sshbuf_new()) == NULL)
+		fatal("%s: sshbuf_new failed", __func__);
 
 	/* Gather keys */
 	va_start(ap, string);
@@ -590,125 +1089,113 @@ percent_expand(const char *string, ...)
 	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';
+			if ((r = sshbuf_put_u8(buf, *string)) != 0) {
+				fatal("%s: sshbuf_put_u8: %s",
+				    __func__, ssh_err(r));
+			}
 			continue;
 		}
 		string++;
 		/* %% case */
 		if (*string == '%')
 			goto append;
-		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__);
+		if (*string == '\0')
+			fatal("%s: invalid format", __func__);
+		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("%s: sshbuf_put: %s",
+					    __func__, ssh_err(r));
+				}
 				break;
 			}
 		}
-		if (j >= num_keys)
+		if (i >= num_keys)
 			fatal("%s: unknown key %%%c", __func__, *string);
 	}
-	return (xstrdup(buf));
+	if ((ret = sshbuf_dup_string(buf)) == NULL)
+		fatal("%s: sshbuf_dup_string failed", __func__);
+	sshbuf_free(buf);
+	return ret;
 #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)
+tun_open(int tun, int mode, char **ifname)
 {
 #if defined(CUSTOM_SYS_TUN_OPEN)
-	return (sys_tun_open(tun, mode));
+	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/tun%d", tun);
+		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/tun%d", 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);
+		return -1;
 	}
 
-	if (fd < 0) {
-		debug("%s: %s open failed: %s", __func__, name, strerror(errno));
-		return (-1);
+	if (fd == -1) {
+		debug("%s: %s open: %s", __func__, name, strerror(errno));
+		return -1;
 	}
 
 	debug("%s: %s mode %d fd %d", __func__, name, mode, fd);
 
-	/* Set the tunnel device operation mode */
-	snprintf(ifr.ifr_name, sizeof(ifr.ifr_name), "tun%d", tun);
+	/* 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)
+	if (ioctl(sock, SIOCGIFFLAGS, &ifr) == -1) {
+		debug("%s: get interface %s flags: %s", __func__,
+		    ifr.ifr_name, strerror(errno));
 		goto failed;
+	}
 
-	/* Set interface mode */
-	ifr.ifr_flags &= ~IFF_UP;
-	if (mode == SSH_TUNMODE_ETHERNET)
-		ifr.ifr_flags |= IFF_LINK0;
-	else
-		ifr.ifr_flags &= ~IFF_LINK0;
-	if (ioctl(sock, SIOCSIFFLAGS, &ifr) == -1)
-		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;
+		}
+	}
 
-	/* Bring interface up */
-	ifr.ifr_flags |= IFF_UP;
-	if (ioctl(sock, SIOCSIFFLAGS, &ifr) == -1)
-		goto failed;
+	if (ifname != NULL)
+		*ifname = xstrdup(ifr.ifr_name);
 
 	close(sock);
-	return (fd);
+	return fd;
 
  failed:
 	if (fd >= 0)
 		close(fd);
 	if (sock >= 0)
 		close(sock);
-	debug("%s: failed to set %s mode %d: %s", __func__, name,
-	    mode, strerror(errno));
-	return (-1);
+	return -1;
 #else
 	error("Tunnel interfaces are not supported on this platform");
 	return (-1);
@@ -725,16 +1212,16 @@ sanitise_stdfd(void)
 		    strerror(errno));
 		exit(1);
 	}
-	while (++dupfd <= 2) {
-		/* Only clobber closed fds */
-		if (fcntl(dupfd, F_GETFL, 0) >= 0)
-			continue;
-		if (dup2(nullfd, dupfd) == -1) {
-			fprintf(stderr, "dup2: %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 > 2)
+	if (nullfd > STDERR_FILENO)
 		close(nullfd);
 }
 
@@ -757,6 +1244,33 @@ tohex(const void *vp, size_t l)
 	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)
 {
@@ -866,8 +1380,8 @@ ms_subtract_diff(struct timeval *start, int *ms)
 {
 	struct timeval diff, finish;
 
-	gettimeofday(&finish, NULL);
-	timersub(&finish, start, &diff);	
+	monotime_tv(&finish);
+	timersub(&finish, start, &diff);
 	*ms -= (diff.tv_sec * 1000) + (diff.tv_usec / 1000);
 }
 
@@ -880,29 +1394,63 @@ ms_to_timeval(struct timeval *tv, int ms)
 	tv->tv_usec = (ms % 1000) * 1000;
 }
 
-time_t
-monotime(void)
+void
+monotime_ts(struct timespec *ts)
 {
-#if defined(HAVE_CLOCK_GETTIME) && \
-    (defined(CLOCK_MONOTONIC) || defined(CLOCK_BOOTTIME))
-	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) {
-#if defined(CLOCK_BOOTTIME)
-		if (clock_gettime(CLOCK_BOOTTIME, &ts) == 0)
-			return (ts.tv_sec);
-#endif
-#if defined(CLOCK_MONOTONIC)
-		if (clock_gettime(CLOCK_MONOTONIC, &ts) == 0)
-			return (ts.tv_sec);
-#endif
+# 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 && (CLOCK_MONOTONIC || CLOCK_BOOTTIME */
+#endif /* HAVE_CLOCK_GETTIME && (BOOTTIME || MONOTONIC || REALTIME) */
+	gettimeofday(&tv, NULL);
+	ts->tv_sec = tv.tv_sec;
+	ts->tv_nsec = (long)tv.tv_usec * 1000;
+}
 
-	return time(NULL);
+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
@@ -910,11 +1458,11 @@ bandwidth_limit_init(struct bwlimit *bw, u_int64_t kbps, size_t buflen)
 {
 	bw->buflen = buflen;
 	bw->rate = kbps;
-	bw->thresh = bw->rate;
+	bw->thresh = buflen;
 	bw->lamt = 0;
 	timerclear(&bw->bwstart);
 	timerclear(&bw->bwend);
-}	
+}
 
 /* Callback from read/write loop to insert bandwidth-limiting delays */
 void
@@ -923,16 +1471,15 @@ 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)) {
-		gettimeofday(&bw->bwstart, NULL);
+		monotime_tv(&bw->bwstart);
 		return;
 	}
-
-	bw->lamt += read_len;
 	if (bw->lamt < bw->thresh)
 		return;
 
-	gettimeofday(&bw->bwend, NULL);
+	monotime_tv(&bw->bwend);
 	timersub(&bw->bwend, &bw->bwstart, &bw->bwend);
 	if (!timerisset(&bw->bwend))
 		return;
@@ -966,7 +1513,7 @@ bandwidth_limit(struct bwlimit *bw, size_t read_len)
 	}
 
 	bw->lamt = 0;
-	gettimeofday(&bw->bwstart, NULL);
+	monotime_tv(&bw->bwstart);
 }
 
 /* Make a template filename for mk[sd]temp() */
@@ -990,6 +1537,7 @@ 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 },
@@ -1011,6 +1559,7 @@ static const struct {
 	{ "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 },
@@ -1066,17 +1615,18 @@ unix_listener(const char *path, int backlog, int unlink_first)
 
 	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: \"%s\" too long for Unix domain socket", __func__,
-		    path);
+	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) {
+	if (sock == -1) {
 		saved_errno = errno;
-		error("socket: %.100s", strerror(errno));
+		error("%s: socket: %.100s", __func__, strerror(errno));
 		errno = saved_errno;
 		return -1;
 	}
@@ -1084,20 +1634,20 @@ unix_listener(const char *path, int backlog, int unlink_first)
 		if (unlink(path) != 0 && errno != ENOENT)
 			error("unlink(%s): %.100s", path, strerror(errno));
 	}
-	if (bind(sock, (struct sockaddr *)&sunaddr, sizeof(sunaddr)) < 0) {
+	if (bind(sock, (struct sockaddr *)&sunaddr, sizeof(sunaddr)) == -1) {
 		saved_errno = errno;
-		error("bind: %.100s", strerror(errno));
+		error("%s: cannot bind to path %s: %s",
+		    __func__, path, strerror(errno));
 		close(sock);
-		error("%s: cannot bind to path: %s", __func__, path);
 		errno = saved_errno;
 		return -1;
 	}
-	if (listen(sock, backlog) < 0) {
+	if (listen(sock, backlog) == -1) {
 		saved_errno = errno;
-		error("listen: %.100s", strerror(errno));
+		error("%s: cannot listen on path %s: %s",
+		    __func__, path, strerror(errno));
 		close(sock);
 		unlink(path);
-		error("%s: cannot listen on path: %s", __func__, path);
 		errno = saved_errno;
 		return -1;
 	}
@@ -1107,7 +1657,7 @@ unix_listener(const char *path, int backlog, int unlink_first)
 void
 sock_set_v6only(int s)
 {
-#ifdef IPV6_V6ONLY
+#if defined(IPV6_V6ONLY) && !defined(__OpenBSD__)
 	int on = 1;
 
 	debug3("%s: set socket %d IPV6_V6ONLY", __func__, s);
@@ -1115,3 +1665,611 @@ sock_set_v6only(int s)
 		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 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;
+}
+
+/* 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;
+#if !defined(ANDROID)
+	struct stat st;
+#endif
+
+	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 !defined(ANDROID)
+		/* /data is owned by system user, which causes this check to fail */
+		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;
+		}
+#endif
+
+		/* 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) == -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) {
+		*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;
+	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;
+}
+
+int
+parse_absolute_time(const char *s, uint64_t *tp)
+{
+	struct tm tm;
+	time_t tt;
+	char buf[32], *fmt;
+
+	*tp = 0;
+
+	/*
+	 * 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 (strlen(s)) {
+	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 (strptime(buf, fmt, &tm) == NULL)
+		return SSH_ERR_INVALID_FORMAT;
+	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 > INT_MAX ? INT_MAX : t; /* XXX revisit in 2038 :P */
+	struct tm tm;
+
+	localtime_r(&tt, &tm);
+	strftime(buf, len, "%Y-%m-%dT%H:%M:%S", &tm);
+}
+
+/* check if path is absolute */
+int
+path_absolute(const char *path)
+{
+	return (*path == '/') ? 1 : 0;
+}
+
+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;
+}
+
+sshsig_t
+ssh_signal(int signum, sshsig_t handler)
+{
+	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;
+}