upstream commit

Add URI support to ssh, sftp and scp.  For example
ssh://user@host or sftp://user@host/path.  The connection parameters
described in draft-ietf-secsh-scp-sftp-ssh-uri-04 are not implemented since
the ssh fingerprint format in the draft uses md5 with no way to specify the
hash function type.  OK djm@

Upstream-ID: 4ba3768b662d6722de59e6ecb00abf2d4bf9cacc

misc.c

@@ -1,4 +1,4 @@
-/* $OpenBSD: misc.c,v 1.113 2017/08/18 05:48:04 djm Exp $ */
+/* $OpenBSD: misc.c,v 1.114 2017/10/21 23:06:24 millert Exp $ */
 /*
  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
  * Copyright (c) 2005,2006 Damien Miller.  All rights reserved.
@@ -395,11 +395,12 @@ 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)
+static char *
+hpdelim2(char **cp, char *delim)
 {
 	char *s, *old;
 
@@ -422,6 +423,8 @@ hpdelim(char **cp)
 
 	case ':':
 	case '/':
+		if (delim != NULL)
+			*delim = *s;
 		*s = '\0';	/* terminate */
 		*cp = s + 1;
 		break;
@@ -433,6 +436,12 @@ hpdelim(char **cp)
 	return old;
 }
 
+char *
+hpdelim(char **cp)
+{
+	return hpdelim2(cp, NULL);
+}
+
 char *
 cleanhostname(char *host)
 {
@@ -466,6 +475,75 @@ 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 = tmp = 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.
@@ -491,7 +569,7 @@ parse_user_host_port(const char *s, char **userp, char **hostp, int *portp)
 	if ((sdup = tmp = strdup(s)) == NULL)
 		return -1;
 	/* Extract optional username */
-	if ((cp = strchr(tmp, '@')) != NULL) {
+	if ((cp = strrchr(tmp, '@')) != NULL) {
 		*cp = '\0';
 		if (*tmp == '\0')
 			goto out;
@@ -527,6 +605,168 @@ parse_user_host_port(const char *s, char **userp, char **hostp, int *portp)
 	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, ...)
@@ -1743,3 +1983,50 @@ child_set_env(char ***envp, u_int *envsizep, const char *name,
 	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;
+}

misc.h

@@ -1,4 +1,4 @@
-/* $OpenBSD: misc.h,v 1.63 2017/08/18 05:48:04 djm Exp $ */
+/* $OpenBSD: misc.h,v 1.64 2017/10/21 23:06:24 millert Exp $ */
 
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
@@ -54,7 +54,9 @@ char	*put_host_port(const char *, u_short);
 char	*hpdelim(char **);
 char	*cleanhostname(char *);
 char	*colon(char *);
+int	 parse_user_host_path(const char *, char **, char **, char **);
 int	 parse_user_host_port(const char *, char **, char **, int *);
+int	 parse_uri(const char *, const char *, char **, char **, int *, char **);
 long	 convtime(const char *);
 char	*tilde_expand_filename(const char *, uid_t);
 char	*percent_expand(const char *, ...) __attribute__((__sentinel__));
@@ -66,6 +68,7 @@ time_t	 monotime(void);
 double	 monotime_double(void);
 void	 lowercase(char *s);
 int	 unix_listener(const char *, int, int);
+int	 valid_domain(char *, int, const char **);
 
 void	 sock_set_v6only(int);