Merge branch 'mh/connect' into pu

Rewrite Git-URL parsing routine (hopefully) without changing any
behaviour.

It has been two months without any support.  We may want to discard
this.

* mh/connect:
  connect: [host:port] is legacy for ssh
  connect: move ssh command line preparation to a separate function
  connect: actively reject git:// urls with a user part
  connect: change the --diag-url output to separate user and host
  connect: make parse_connect_url() return the user part of the url as a separate value
  connect: group CONNECT_DIAG_URL handling code
  connect: make parse_connect_url() return separated host and port
  connect: re-derive a host:port string from the separate host and port variables
  connect: call get_host_and_port() earlier
  connect: document why we sometimes call get_port after get_host_and_port

Author: gitster

connect.c

@@ -363,18 +363,16 @@ static const char *ai_name(const struct addrinfo *ai)
 /*
  * Returns a connected socket() fd, or else die()s.
  */
-static int git_tcp_connect_sock(char *host, int flags)
+static int git_tcp_connect_sock(const char *host, const char *port, int flags)
 {
 	struct strbuf error_message = STRBUF_INIT;
 	int sockfd = -1;
-	const char *port = STR(DEFAULT_GIT_PORT);
 	struct addrinfo hints, *ai0, *ai;
 	int gai;
 	int cnt = 0;
 
-	get_host_and_port(&host, &port);
-	if (!*port)
-		port = "<none>";
+	if (!port)
+		port = STR(DEFAULT_GIT_PORT);
 
 	memset(&hints, 0, sizeof(hints));
 	if (flags & CONNECT_IPV4)
@@ -431,19 +429,19 @@ static int git_tcp_connect_sock(char *host, int flags)
 /*
  * Returns a connected socket() fd, or else die()s.
  */
-static int git_tcp_connect_sock(char *host, int flags)
+static int git_tcp_connect_sock(const char *host, const char *port, int flags)
 {
 	struct strbuf error_message = STRBUF_INIT;
 	int sockfd = -1;
-	const char *port = STR(DEFAULT_GIT_PORT);
 	char *ep;
 	struct hostent *he;
 	struct sockaddr_in sa;
 	char **ap;
 	unsigned int nport;
 	int cnt;
 
-	get_host_and_port(&host, &port);
+	if (!port)
+		port = STR(DEFAULT_GIT_PORT);
 
 	if (flags & CONNECT_VERBOSE)
 		fprintf(stderr, "Looking up %s ... ", host);
@@ -502,9 +500,10 @@ static int git_tcp_connect_sock(char *host, int flags)
 #endif /* NO_IPV6 */
 
 
-static void git_tcp_connect(int fd[2], char *host, int flags)
+static void git_tcp_connect(int fd[2], const char *host, const char *port,
+			    int flags)
 {
-	int sockfd = git_tcp_connect_sock(host, flags);
+	int sockfd = git_tcp_connect_sock(host, port, flags);
 
 	fd[0] = sockfd;
 	fd[1] = dup(sockfd);
@@ -570,18 +569,16 @@ static int git_use_proxy(const char *host)
 	return (git_proxy_command && *git_proxy_command);
 }
 
-static struct child_process *git_proxy_connect(int fd[2], char *host)
+static struct child_process *git_proxy_connect(int fd[2], const char *host,
+					       const char *port)
 {
-	const char *port = STR(DEFAULT_GIT_PORT);
 	struct child_process *proxy;
 
-	get_host_and_port(&host, &port);
-
 	proxy = xmalloc(sizeof(*proxy));
 	child_process_init(proxy);
 	argv_array_push(&proxy->args, git_proxy_command);
 	argv_array_push(&proxy->args, host);
-	argv_array_push(&proxy->args, port);
+	argv_array_push(&proxy->args, port ? port : STR(DEFAULT_GIT_PORT));
 	proxy->in = -1;
 	proxy->out = -1;
 	if (start_command(proxy))
@@ -611,11 +608,14 @@ static char *get_port(char *host)
  * Extract protocol and relevant parts from the specified connection URL.
  * The caller must free() the returned strings.
  */
-static enum protocol parse_connect_url(const char *url_orig, char **ret_host,
+static enum protocol parse_connect_url(const char *url_orig, char **ret_user,
+				       char **ret_host, char **ret_port,
 				       char **ret_path)
 {
 	char *url;
 	char *host, *path;
+	const char *user = NULL;
+	const char *port = NULL;
 	char *end;
 	int separator = '/';
 	enum protocol protocol = PROTO_LOCAL;
@@ -638,10 +638,7 @@ static enum protocol parse_connect_url(const char *url_orig, char **ret_host,
 		}
 	}
 
-	/*
-	 * Don't do destructive transforms as protocol code does
-	 * '[]' unwrapping in get_host_and_port()
-	 */
+	/* '[]' unwrapping is done in get_host_and_port() */
 	end = host_end(&host, 0);
 
 	if (protocol == PROTO_LOCAL)
@@ -670,14 +667,40 @@ static enum protocol parse_connect_url(const char *url_orig, char **ret_host,
 	path = xstrdup(path);
 	*end = '\0';
 
+	get_host_and_port(&host, &port);
+
+	if (*host) {
+		/*
+		 * At this point, the host part may look like user@host:port.
+		 * As the `user` portion tends to be less strict than
+		 * `host:port`, we first put it out of the equation: since a
+		 * hostname cannot contain a '@', we start from the last '@'
+		 * in the string.
+		 */
+		char *end_user = strrchr(host, '@');
+		if (end_user) {
+			*end_user = '\0';
+			user = host;
+			host = end_user + 1;
+		}
+	}
+	/*
+	 * get_host_and_port does not return a port in the [host:port]:path
+	 * case. In that case, it is called with "[host:port]" and returns
+	 * "host:port" and NULL. To support this undocumented legacy
+	 * (for ssh only) we still need to split the port.
+	 */
+	if (!port && protocol == PROTO_SSH)
+		port = get_port(host);
+
+	*ret_user = user ? xstrdup(user) : NULL;
 	*ret_host = xstrdup(host);
+	*ret_port = port ? xstrdup(port) : NULL;
 	*ret_path = path;
 	free(url);
 	return protocol;
 }
 
-static struct child_process no_fork = CHILD_PROCESS_INIT;
-
 static const char *get_ssh_command(void)
 {
 	const char *ssh;
@@ -691,6 +714,63 @@ static const char *get_ssh_command(void)
 	return NULL;
 }
 
+static int prepare_ssh_command(struct argv_array *cmd, const char *user,
+			       const char *host, const char *port, int flags)
+{
+	const char *ssh;
+	int putty = 0, tortoiseplink = 0, use_shell = 1;
+	transport_check_allowed("ssh");
+
+	ssh = get_ssh_command();
+	if (!ssh) {
+		const char *base;
+		char *ssh_dup;
+
+		/*
+		 * GIT_SSH is the no-shell version of
+		 * GIT_SSH_COMMAND (and must remain so for
+		 * historical compatibility).
+		 */
+		use_shell = 0;
+
+		ssh = getenv("GIT_SSH");
+		if (!ssh)
+			ssh = "ssh";
+
+		ssh_dup = xstrdup(ssh);
+		base = basename(ssh_dup);
+
+		tortoiseplink = !strcasecmp(base, "tortoiseplink") ||
+			!strcasecmp(base, "tortoiseplink.exe");
+		putty = tortoiseplink ||
+			!strcasecmp(base, "plink") ||
+			!strcasecmp(base, "plink.exe");
+
+		free(ssh_dup);
+	}
+
+	argv_array_push(cmd, ssh);
+	if (flags & CONNECT_IPV4)
+		argv_array_push(cmd, "-4");
+	else if (flags & CONNECT_IPV6)
+		argv_array_push(cmd, "-6");
+	if (tortoiseplink)
+		argv_array_push(cmd, "-batch");
+	if (port) {
+		/* P is for PuTTY, p is for OpenSSH */
+		argv_array_push(cmd, putty ? "-P" : "-p");
+		argv_array_push(cmd, port);
+	}
+	if (user)
+		argv_array_pushf(cmd, "%s@%s", user, host);
+	else
+		argv_array_push(cmd, host);
+
+	return use_shell;
+}
+
+static struct child_process no_fork = CHILD_PROCESS_INIT;
+
 /*
  * This returns a dummy child_process if the transport protocol does not
  * need fork(2), or a struct child_process object if it does.  Once done,
@@ -705,7 +785,7 @@ static const char *get_ssh_command(void)
 struct child_process *git_connect(int fd[2], const char *url,
 				  const char *prog, int flags)
 {
-	char *hostandport, *path;
+	char *user, *host, *port, *path;
 	struct child_process *conn = &no_fork;
 	enum protocol protocol;
 	struct strbuf cmd = STRBUF_INIT;
@@ -715,11 +795,13 @@ struct child_process *git_connect(int fd[2], const char *url,
 	 */
 	signal(SIGCHLD, SIG_DFL);
 
-	protocol = parse_connect_url(url, &hostandport, &path);
-	if ((flags & CONNECT_DIAG_URL) && (protocol != PROTO_SSH)) {
+	protocol = parse_connect_url(url, &user, &host, &port, &path);
+	if (flags & CONNECT_DIAG_URL) {
 		printf("Diag: url=%s\n", url ? url : "NULL");
 		printf("Diag: protocol=%s\n", prot_name(protocol));
-		printf("Diag: hostandport=%s\n", hostandport ? hostandport : "NULL");
+		printf("Diag: user=%s\n", user ? user : "NULL");
+		printf("Diag: host=%s\n", host ? host : "NULL");
+		printf("Diag: port=%s\n", port ? port : "NONE");
 		printf("Diag: path=%s\n", path ? path : "NULL");
 		conn = NULL;
 	} else if (protocol == PROTO_GIT) {
@@ -728,21 +810,38 @@ struct child_process *git_connect(int fd[2], const char *url,
 		 * connect, unless the user has overridden us in
 		 * the environment.
 		 */
-		char *target_host = getenv("GIT_OVERRIDE_VIRTUAL_HOST");
-		if (target_host)
-			target_host = xstrdup(target_host);
-		else
-			target_host = xstrdup(hostandport);
+		struct strbuf target_host = STRBUF_INIT;
+		struct strbuf virtual_host = STRBUF_INIT;
+		const char *colon = strchr(host, ':');
+		char *override_vhost = getenv("GIT_OVERRIDE_VIRTUAL_HOST");
+
+		if (user)
+			die("user@host is not allowed in git:// urls");
+
+		/* If the host contains a colon (ipv6 address), it needs to
+		 * be enclosed with square brackets. */
+		if (colon)
+			strbuf_addch(&target_host, '[');
+		strbuf_addstr(&target_host, host);
+		if (colon)
+			strbuf_addch(&target_host, ']');
+		if (port) {
+			strbuf_addch(&target_host, ':');
+			strbuf_addstr(&target_host, port);
+		}
+
+		strbuf_addstr(&virtual_host, override_vhost ? override_vhost
+							    : target_host.buf);
 
 		transport_check_allowed("git");
 
 		/* These underlying connection commands die() if they
 		 * cannot connect.
 		 */
-		if (git_use_proxy(hostandport))
-			conn = git_proxy_connect(fd, hostandport);
+		if (git_use_proxy(target_host.buf))
+			conn = git_proxy_connect(fd, host, port);
 		else
-			git_tcp_connect(fd, hostandport, flags);
+			git_tcp_connect(fd, host, port, flags);
 		/*
 		 * Separate original protocol components prog and path
 		 * from extended host header with a NUL byte.
@@ -753,8 +852,9 @@ struct child_process *git_connect(int fd[2], const char *url,
 		packet_write_fmt(fd[1],
 			     "%s %s%chost=%s%c",
 			     prog, path, 0,
-			     target_host, 0);
-		free(target_host);
+			     virtual_host.buf, 0);
+		strbuf_release(&virtual_host);
+		strbuf_release(&target_host);
 	} else {
 		conn = xmalloc(sizeof(*conn));
 		child_process_init(conn);
@@ -765,74 +865,12 @@ struct child_process *git_connect(int fd[2], const char *url,
 
 		/* remove repo-local variables from the environment */
 		conn->env = local_repo_env;
-		conn->use_shell = 1;
 		conn->in = conn->out = -1;
 		if (protocol == PROTO_SSH) {
-			const char *ssh;
-			int putty = 0, tortoiseplink = 0;
-			char *ssh_host = hostandport;
-			const char *port = NULL;
-			transport_check_allowed("ssh");
-			get_host_and_port(&ssh_host, &port);
-
-			if (!port)
-				port = get_port(ssh_host);
-
-			if (flags & CONNECT_DIAG_URL) {
-				printf("Diag: url=%s\n", url ? url : "NULL");
-				printf("Diag: protocol=%s\n", prot_name(protocol));
-				printf("Diag: userandhost=%s\n", ssh_host ? ssh_host : "NULL");
-				printf("Diag: port=%s\n", port ? port : "NONE");
-				printf("Diag: path=%s\n", path ? path : "NULL");
-
-				free(hostandport);
-				free(path);
-				free(conn);
-				return NULL;
-			}
-
-			ssh = get_ssh_command();
-			if (!ssh) {
-				const char *base;
-				char *ssh_dup;
-
-				/*
-				 * GIT_SSH is the no-shell version of
-				 * GIT_SSH_COMMAND (and must remain so for
-				 * historical compatibility).
-				 */
-				conn->use_shell = 0;
-
-				ssh = getenv("GIT_SSH");
-				if (!ssh)
-					ssh = "ssh";
-
-				ssh_dup = xstrdup(ssh);
-				base = basename(ssh_dup);
-
-				tortoiseplink = !strcasecmp(base, "tortoiseplink") ||
-					!strcasecmp(base, "tortoiseplink.exe");
-				putty = tortoiseplink ||
-					!strcasecmp(base, "plink") ||
-					!strcasecmp(base, "plink.exe");
-
-				free(ssh_dup);
-			}
-
-			argv_array_push(&conn->args, ssh);
-			if (flags & CONNECT_IPV4)
-				argv_array_push(&conn->args, "-4");
-			else if (flags & CONNECT_IPV6)
-				argv_array_push(&conn->args, "-6");
-			if (tortoiseplink)
-				argv_array_push(&conn->args, "-batch");
-			if (port) {
-				/* P is for PuTTY, p is for OpenSSH */
-				argv_array_push(&conn->args, putty ? "-P" : "-p");
-				argv_array_push(&conn->args, port);
-			}
-			argv_array_push(&conn->args, ssh_host);
+			conn->use_shell = prepare_ssh_command(
+				&conn->args, user, host, port, flags);
 		} else {
+			conn->use_shell = 1;
 			transport_check_allowed("file");
 		}
 		argv_array_push(&conn->args, cmd.buf);
@@ -844,7 +882,9 @@ struct child_process *git_connect(int fd[2], const char *url,
 		fd[1] = conn->in;  /* write to child's stdin */
 		strbuf_release(&cmd);
 	}
-	free(hostandport);
+	free(user);
+	free(host);
+	free(port);
 	free(path);
 	return conn;
 }