Commit message: git_connect_git(): forbid newlines in host and path

When we connect to a git:// server, we send an initial request that
looks something like:

  002dgit-upload-pack repo.git\0host=example.com

If the repo path contains a newline, then it's included literally, and
we get:

  002egit-upload-pack repo
  .git\0host=example.com

This works fine if you really do have a newline in your repository name;
the server side uses the pktline framing to parse the string, not
newlines. However, there are many _other_ protocols in the wild that do
parse on newlines, such as HTTP. So a carefully constructed git:// URL
can actually turn into a valid HTTP request. For example:

  git://localhost:1234/%0d%0a%0d%0aGET%20/%20HTTP/1.1 %0d%0aHost:localhost%0d%0a%0d%0a

becomes:

  0050git-upload-pack /
  GET / HTTP/1.1
  Host:localhost

  host=localhost:1234

on the wire. Again, this isn't a problem for a real Git server, but it
does mean that feeding a malicious URL to Git (e.g., through a
submodule) can cause it to make unexpected cross-protocol requests.
Since repository names with newlines are presumably quite rare (and
indeed, we already disallow them in git-over-http), let's just disallow
them over this protocol.

Hostnames could likewise inject a newline, but this is unlikely a
problem in practice; we'd try resolving the hostname with a newline in
it, which wouldn't work. Still, it doesn't hurt to err on the side of
caution there, since we would not expect them to work in the first
place.

The ssh and local code paths are unaffected by this patch. In both cases
we're trying to run upload-pack via a shell, and will quote the newline
so that it makes it intact. An attacker can point an ssh url at an
arbitrary port, of course, but unless there's an actual ssh server
there, we'd never get as far as sending our shell command anyway.  We
_could_ similarly restrict newlines in those protocols out of caution,
but there seems little benefit to doing so.

The new test here is run alongside the git-daemon tests, which cover the
same protocol, but it shouldn't actually contact the daemon at all.  In
theory we could make the test more robust by setting up an actual
repository with a newline in it (so that our clone would succeed if our
new check didn't kick in). But a repo directory with newline in it is
likely not portable across all filesystems. Likewise, we could check
git-daemon's log that it was not contacted at all, but we do not
currently record the log (and anyway, it would make the test racy with
the daemon's log write). We'll just check the client-side stderr to make
sure we hit the expected code path.

Reported-by: Harold Kim <h.kim@flatt.tech>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
CVE: CVE-2021-40330
CWE: NVD-CWE-noinfo
Vulnerability description: git_connect_git in connect.c in Git before 2.30.1 allows a repository path to contain a newline character, which may result in unexpected cross-protocol requests, as demonstrated by the git://localhost:1234/%0d%0a%0d%0aGET%20/%20HTTP/1.1 substring.

Project: git
File: connect.c

enum protocol_version discover_version(struct packet_reader *reader)
{
	enum protocol_version version = protocol_unknown_version;

	/*
	 * Peek the first line of the server's response to
	 * determine the protocol version the server is speaking.
	 */
	switch (packet_reader_peek(reader)) {
	case PACKET_READ_EOF:
		die_initial_contact(0);
	case PACKET_READ_FLUSH:
	case PACKET_READ_DELIM:
		version = protocol_v0;
		break;
	case PACKET_READ_NORMAL:
		version = determine_protocol_version_client(reader->line);
		break;
	}

	switch (version) {
	case protocol_v2:
		process_capabilities_v2(reader);
		break;
	case protocol_v1:
		/* Read the peeked version line */
		packet_reader_read(reader);
		break;
	case protocol_v0:
		break;
	case protocol_unknown_version:
		BUG("unknown protocol version");
	}

	return version;
}

Project: git
File: connect.c

static enum protocol get_protocol(const char *name)
{
	if (!strcmp(name, "ssh"))
		return PROTO_SSH;
	if (!strcmp(name, "git"))
		return PROTO_GIT;
	if (!strcmp(name, "git+ssh")) /* deprecated - do not use */
		return PROTO_SSH;
	if (!strcmp(name, "ssh+git")) /* deprecated - do not use */
		return PROTO_SSH;
	if (!strcmp(name, "file"))
		return PROTO_FILE;
	die(_("protocol '%s' is not supported"), name);
}

Project: git
File: connect.c

static struct child_process *git_proxy_connect(int fd[2], char *host)
{
	const char *port = STR(DEFAULT_GIT_PORT);
	struct child_process *proxy;

	get_host_and_port(&host, &port);

	if (looks_like_command_line_option(host))
		die(_("strange hostname '%s' blocked"), host);
	if (looks_like_command_line_option(port))
		die(_("strange port '%s' blocked"), 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);
	proxy->in = -1;
	proxy->out = -1;
	if (start_command(proxy))
		die(_("cannot start proxy %s"), git_proxy_command);
	fd[0] = proxy->out; /* read from proxy stdout */
	fd[1] = proxy->in;  /* write to proxy stdin */
	return proxy;
}

Project: git
File: connect.c

static struct child_process *git_tcp_connect(int fd[2], char *host, int flags)
{
	int sockfd = git_tcp_connect_sock(host, flags);

	fd[0] = sockfd;
	fd[1] = dup(sockfd);

	return &no_fork;
}

Project: git
File: connect.c

static void annotate_refs_with_symref_info(struct ref *ref)
{
	struct string_list symref = STRING_LIST_INIT_DUP;
	const char *feature_list = server_capabilities_v1;

	while (feature_list) {
		int len;
		const char *val;

		val = parse_feature_value(feature_list, "symref", &len);
		if (!val)
			break;
		parse_one_symref_info(&symref, val, len);
		feature_list = val + 1;
	}
	string_list_sort(&symref);

	for (; ref; ref = ref->next) {
		struct string_list_item *item;
		item = string_list_lookup(&symref, ref->name);
		if (!item)
			continue;
		ref->symref = xstrdup((char *)item->util);
	}
	string_list_clear(&symref, 0);
}

Project: git
File: connect.c

struct child_process *git_connect(int fd[2], const char *url,
				  const char *prog, int flags)
{
	char *hostandport, *path;
	struct child_process *conn;
	enum protocol protocol;
	enum protocol_version version = get_protocol_version_config();

	/*
	 * NEEDSWORK: If we are trying to use protocol v2 and we are planning
	 * to perform a push, then fallback to v0 since the client doesn't know
	 * how to push yet using v2.
	 */
	if (version == protocol_v2 && !strcmp("git-receive-pack", prog))
		version = protocol_v0;

	/* Without this we cannot rely on waitpid() to tell
	 * what happened to our children.
	 */
	signal(SIGCHLD, SIG_DFL);

	protocol = parse_connect_url(url, &hostandport, &path);
	if ((flags & CONNECT_DIAG_URL) && (protocol != PROTO_SSH)) {
		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: path=%s\n", path ? path : "NULL");
		conn = NULL;
	} else if (protocol == PROTO_GIT) {
		conn = git_connect_git(fd, hostandport, path, prog, version, flags);
	} else {
		struct strbuf cmd = STRBUF_INIT;
		const char *const *var;

		conn = xmalloc(sizeof(*conn));
		child_process_init(conn);

		if (looks_like_command_line_option(path))
			die(_("strange pathname '%s' blocked"), path);

		strbuf_addstr(&cmd, prog);
		strbuf_addch(&cmd, ' ');
		sq_quote_buf(&cmd, path);

		/* remove repo-local variables from the environment */
		for (var = local_repo_env; *var; var++)
			argv_array_push(&conn->env_array, *var);

		conn->use_shell = 1;
		conn->in = conn->out = -1;
		if (protocol == PROTO_SSH) {
			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);
				strbuf_release(&cmd);
				return NULL;
			}
			fill_ssh_args(conn, ssh_host, port, version, flags);
		} else {
			transport_check_allowed("file");
			if (version > 0) {
				argv_array_pushf(&conn->env_array, GIT_PROTOCOL_ENVIRONMENT "=version=%d",
						 version);
			}
		}
		argv_array_push(&conn->args, cmd.buf);

		if (start_command(conn))
			die(_("unable to fork"));

		fd[0] = conn->out; /* read from child's stdout */
		fd[1] = conn->in;  /* write to child's stdin */
		strbuf_release(&cmd);
	}
	free(hostandport);
	free(path);
	return conn;
}

Project: git
File: connect.c

static int git_tcp_connect_sock(char *host, 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>";

	memset(&hints, 0, sizeof(hints));
	if (flags & CONNECT_IPV4)
		hints.ai_family = AF_INET;
	else if (flags & CONNECT_IPV6)
		hints.ai_family = AF_INET6;
	hints.ai_socktype = SOCK_STREAM;
	hints.ai_protocol = IPPROTO_TCP;

	if (flags & CONNECT_VERBOSE)
		fprintf(stderr, _("Looking up %s ... "), host);

	gai = getaddrinfo(host, port, &hints, &ai);
	if (gai)
		die(_("unable to look up %s (port %s) (%s)"), host, port, gai_strerror(gai));

	if (flags & CONNECT_VERBOSE)
		/* TRANSLATORS: this is the end of "Looking up %s ... " */
		fprintf(stderr, _("done.\nConnecting to %s (port %s) ... "), host, port);

	for (ai0 = ai; ai; ai = ai->ai_next, cnt++) {
		sockfd = socket(ai->ai_family,
				ai->ai_socktype, ai->ai_protocol);
		if ((sockfd < 0) ||
		    (connect(sockfd, ai->ai_addr, ai->ai_addrlen) < 0)) {
			strbuf_addf(&error_message, "%s[%d: %s]: errno=%s\n",
				    host, cnt, ai_name(ai), strerror(errno));
			if (0 <= sockfd)
				close(sockfd);
			sockfd = -1;
			continue;
		}
		if (flags & CONNECT_VERBOSE)
			fprintf(stderr, "%s ", ai_name(ai));
		break;
	}

	freeaddrinfo(ai0);

	if (sockfd < 0)
		die(_("unable to connect to %s:\n%s"), host, error_message.buf);

	enable_keepalive(sockfd);

	if (flags & CONNECT_VERBOSE)
		/* TRANSLATORS: this is the end of "Connecting to %s (port %s) ... " */
		fprintf_ln(stderr, _("done."));

	strbuf_release(&error_message);

	return sockfd;
}

Project: git
File: connect.c

static NORETURN void die_initial_contact(int unexpected)
{
	/*
	 * A hang-up after seeing some response from the other end
	 * means that it is unexpected, as we know the other end is
	 * willing to talk to us.  A hang-up before seeing any
	 * response does not necessarily mean an ACL problem, though.
	 */
	if (unexpected)
		die(_("the remote end hung up upon initial contact"));
	else
		die(_("Could not read from remote repository.\n\n"
		      "Please make sure you have the correct access rights\n"
		      "and the repository exists."));
}

Project: git
File: connect.c

static int process_ref(const char *line, int len, struct ref ***list,
		       unsigned int flags, struct oid_array *extra_have)
{
	struct object_id old_oid;
	const char *name;

	if (parse_oid_hex(line, &old_oid, &name))
		return 0;
	if (*name != ' ')
		return 0;
	name++;

	if (extra_have && !strcmp(name, ".have")) {
		oid_array_append(extra_have, &old_oid);
	} else if (!strcmp(name, "capabilities^{}")) {
		die(_("protocol error: unexpected capabilities^{}"));
	} else if (check_ref(name, flags)) {
		struct ref *ref = alloc_ref(name);
		oidcpy(&ref->old_oid, &old_oid);
		**list = ref;
		*list = &ref->next;
	}
	check_no_capabilities(line, len);
	return 1;
}

Project: git
File: connect.c

int server_supports_v2(const char *c, int die_on_error)
{
	int i;

	for (i = 0; i < server_capabilities_v2.argc; i++) {
		const char *out;
		if (skip_prefix(server_capabilities_v2.argv[i], c, &out) &&
		    (!*out || *out == '='))
			return 1;
	}

	if (die_on_error)
		die(_("server doesn't support '%s'"), c);

	return 0;
}

Project: git
File: connect.c

static enum protocol parse_connect_url(const char *url_orig, char **ret_host,
				       char **ret_path)
{
	char *url;
	char *host, *path;
	char *end;
	int separator = '/';
	enum protocol protocol = PROTO_LOCAL;

	if (is_url(url_orig))
		url = url_decode(url_orig);
	else
		url = xstrdup(url_orig);

	host = strstr(url, "://");
	if (host) {
		*host = '\0';
		protocol = get_protocol(url);
		host += 3;
	} else {
		host = url;
		if (!url_is_local_not_ssh(url)) {
			protocol = PROTO_SSH;
			separator = ':';
		}
	}

	/*
	 * Don't do destructive transforms as protocol code does
	 * '[]' unwrapping in get_host_and_port()
	 */
	end = host_end(&host, 0);

	if (protocol == PROTO_LOCAL)
		path = end;
	else if (protocol == PROTO_FILE && has_dos_drive_prefix(end))
		path = end; /* "file://$(pwd)" may be "file://C:/projects/repo" */
	else
		path = strchr(end, separator);

	if (!path || !*path)
		die(_("no path specified; see 'git help pull' for valid url syntax"));

	/*
	 * null-terminate hostname and point path to ~ for URL's like this:
	 *    ssh://host.xz/~user/repo
	 */

	end = path; /* Need to \0 terminate host here */
	if (separator == ':')
		path++; /* path starts after ':' */
	if (protocol == PROTO_GIT || protocol == PROTO_SSH) {
		if (path[1] == '~')
			path++;
	}

	path = xstrdup(path);
	*end = '\0';

	*ret_host = xstrdup(host);
	*ret_path = path;
	free(url);
	return protocol;
}

Project: git
File: connect.c

static int process_dummy_ref(const char *line)
{
	struct object_id oid;
	const char *name;

	if (parse_oid_hex(line, &oid, &name))
		return 0;
	if (*name != ' ')
		return 0;
	name++;

	return oideq(&null_oid, &oid) && !strcmp(name, "capabilities^{}");
}

Project: git
File: connect.c

static void override_ssh_variant(enum ssh_variant *ssh_variant)
{
	const char *variant = getenv("GIT_SSH_VARIANT");

	if (!variant && git_config_get_string_const("ssh.variant", &variant))
		return;

	if (!strcmp(variant, "auto"))
		*ssh_variant = VARIANT_AUTO;
	else if (!strcmp(variant, "plink"))
		*ssh_variant = VARIANT_PLINK;
	else if (!strcmp(variant, "putty"))
		*ssh_variant = VARIANT_PUTTY;
	else if (!strcmp(variant, "tortoiseplink"))
		*ssh_variant = VARIANT_TORTOISEPLINK;
	else if (!strcmp(variant, "simple"))
		*ssh_variant = VARIANT_SIMPLE;
	else
		*ssh_variant = VARIANT_SSH;
}

Project: git
File: connect.c

static int git_tcp_connect_sock(char *host, 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 (flags & CONNECT_VERBOSE)
		fprintf(stderr, _("Looking up %s ... "), host);

	he = gethostbyname(host);
	if (!he)
		die(_("unable to look up %s (%s)"), host, hstrerror(h_errno));
	nport = strtoul(port, &ep, 10);
	if ( ep == port || *ep ) {
		/* Not numeric */
		struct servent *se = getservbyname(port,"tcp");
		if ( !se )
			die(_("unknown port %s"), port);
		nport = se->s_port;
	}

	if (flags & CONNECT_VERBOSE)
		/* TRANSLATORS: this is the end of "Looking up %s ... " */
		fprintf(stderr, _("done.\nConnecting to %s (port %s) ... "), host, port);

	for (cnt = 0, ap = he->h_addr_list; *ap; ap++, cnt++) {
		memset(&sa, 0, sizeof sa);
		sa.sin_family = he->h_addrtype;
		sa.sin_port = htons(nport);
		memcpy(&sa.sin_addr, *ap, he->h_length);

		sockfd = socket(he->h_addrtype, SOCK_STREAM, 0);
		if ((sockfd < 0) ||
		    connect(sockfd, (struct sockaddr *)&sa, sizeof sa) < 0) {
			strbuf_addf(&error_message, "%s[%d: %s]: errno=%s\n",
				host,
				cnt,
				inet_ntoa(*(struct in_addr *)&sa.sin_addr),
				strerror(errno));
			if (0 <= sockfd)
				close(sockfd);
			sockfd = -1;
			continue;
		}
		if (flags & CONNECT_VERBOSE)
			fprintf(stderr, "%s ",
				inet_ntoa(*(struct in_addr *)&sa.sin_addr));
		break;
	}

	if (sockfd < 0)
		die(_("unable to connect to %s:\n%s"), host, error_message.buf);

	enable_keepalive(sockfd);

	if (flags & CONNECT_VERBOSE)
		/* TRANSLATORS: this is the end of "Connecting to %s (port %s) ... " */
		fprintf_ln(stderr, _("done."));

	return sockfd;
}

Project: git
File: connect.c

static void enable_keepalive(int sockfd)
{
	int ka = 1;

	if (setsockopt(sockfd, SOL_SOCKET, SO_KEEPALIVE, &ka, sizeof(ka)) < 0)
		error_errno(_("unable to set SO_KEEPALIVE on socket"));
}

Project: git
File: connect.c

static void push_ssh_options(struct argv_array *args, struct argv_array *env,
			     enum ssh_variant variant, const char *port,
			     enum protocol_version version, int flags)
{
	if (variant == VARIANT_SSH &&
	    version > 0) {
		argv_array_push(args, "-o");
		argv_array_push(args, "SendEnv=" GIT_PROTOCOL_ENVIRONMENT);
		argv_array_pushf(env, GIT_PROTOCOL_ENVIRONMENT "=version=%d",
				 version);
	}

	if (flags & CONNECT_IPV4) {
		switch (variant) {
		case VARIANT_AUTO:
			BUG("VARIANT_AUTO passed to push_ssh_options");
		case VARIANT_SIMPLE:
			die(_("ssh variant 'simple' does not support -4"));
		case VARIANT_SSH:
		case VARIANT_PLINK:
		case VARIANT_PUTTY:
		case VARIANT_TORTOISEPLINK:
			argv_array_push(args, "-4");
		}
	} else if (flags & CONNECT_IPV6) {
		switch (variant) {
		case VARIANT_AUTO:
			BUG("VARIANT_AUTO passed to push_ssh_options");
		case VARIANT_SIMPLE:
			die(_("ssh variant 'simple' does not support -6"));
		case VARIANT_SSH:
		case VARIANT_PLINK:
		case VARIANT_PUTTY:
		case VARIANT_TORTOISEPLINK:
			argv_array_push(args, "-6");
		}
	}

	if (variant == VARIANT_TORTOISEPLINK)
		argv_array_push(args, "-batch");

	if (port) {
		switch (variant) {
		case VARIANT_AUTO:
			BUG("VARIANT_AUTO passed to push_ssh_options");
		case VARIANT_SIMPLE:
			die(_("ssh variant 'simple' does not support setting port"));
		case VARIANT_SSH:
			argv_array_push(args, "-p");
			break;
		case VARIANT_PLINK:
		case VARIANT_PUTTY:
		case VARIANT_TORTOISEPLINK:
			argv_array_push(args, "-P");
		}

		argv_array_push(args, port);
	}
}

Project: git
File: connect.c

static enum ssh_variant determine_ssh_variant(const char *ssh_command,
					      int is_cmdline)
{
	enum ssh_variant ssh_variant = VARIANT_AUTO;
	const char *variant;
	char *p = NULL;

	override_ssh_variant(&ssh_variant);

	if (ssh_variant != VARIANT_AUTO)
		return ssh_variant;

	if (!is_cmdline) {
		p = xstrdup(ssh_command);
		variant = basename(p);
	} else {
		const char **ssh_argv;

		p = xstrdup(ssh_command);
		if (split_cmdline(p, &ssh_argv) > 0) {
			variant = basename((char *)ssh_argv[0]);
			/*
			 * At this point, variant points into the buffer
			 * referenced by p, hence we do not need ssh_argv
			 * any longer.
			 */
			free(ssh_argv);
		} else {
			free(p);
			return ssh_variant;
		}
	}

	if (!strcasecmp(variant, "ssh") ||
	    !strcasecmp(variant, "ssh.exe"))
		ssh_variant = VARIANT_SSH;
	else if (!strcasecmp(variant, "plink") ||
		 !strcasecmp(variant, "plink.exe"))
		ssh_variant = VARIANT_PLINK;
	else if (!strcasecmp(variant, "tortoiseplink") ||
		 !strcasecmp(variant, "tortoiseplink.exe"))
		ssh_variant = VARIANT_TORTOISEPLINK;

	free(p);
	return ssh_variant;
}

Project: git
File: connect.c

struct ref **get_remote_heads(struct packet_reader *reader,
			      struct ref **list, unsigned int flags,
			      struct oid_array *extra_have,
			      struct oid_array *shallow_points)
{
	struct ref **orig_list = list;
	int len = 0;
	enum get_remote_heads_state state = EXPECTING_FIRST_REF;
	const char *arg;

	*list = NULL;

	while (state != EXPECTING_DONE) {
		switch (packet_reader_read(reader)) {
		case PACKET_READ_EOF:
			die_initial_contact(1);
		case PACKET_READ_NORMAL:
			len = reader->pktlen;
			if (len > 4 && skip_prefix(reader->line, "ERR ", &arg))
				die(_("remote error: %s"), arg);
			break;
		case PACKET_READ_FLUSH:
			state = EXPECTING_DONE;
			break;
		case PACKET_READ_DELIM:
			die(_("invalid packet"));
		}

		switch (state) {
		case EXPECTING_FIRST_REF:
			process_capabilities(reader->line, &len);
			if (process_dummy_ref(reader->line)) {
				state = EXPECTING_SHALLOW;
				break;
			}
			state = EXPECTING_REF;
			/* fallthrough */
		case EXPECTING_REF:
			if (process_ref(reader->line, len, &list, flags, extra_have))
				break;
			state = EXPECTING_SHALLOW;
			/* fallthrough */
		case EXPECTING_SHALLOW:
			if (process_shallow(reader->line, len, shallow_points))
				break;
			die(_("protocol error: unexpected '%s'"), reader->line);
		case EXPECTING_DONE:
			break;
		}
	}

	annotate_refs_with_symref_info(*orig_list);

	return list;
}

Project: git
File: connect.c

static void process_capabilities(const char *line, int *len)
{
	int nul_location = strlen(line);
	if (nul_location == *len)
		return;
	server_capabilities_v1 = xstrdup(line + nul_location + 1);
	*len = nul_location;
}

Project: git
File: connect.c

const char *server_feature_value(const char *feature, int *len)
{
	return parse_feature_value(server_capabilities_v1, feature, len);
}

Project: git
File: connect.c

static int process_shallow(const char *line, int len,
			   struct oid_array *shallow_points)
{
	const char *arg;
	struct object_id old_oid;

	if (!skip_prefix(line, "shallow ", &arg))
		return 0;

	if (get_oid_hex(arg, &old_oid))
		die(_("protocol error: expected shallow sha-1, got '%s'"), arg);
	if (!shallow_points)
		die(_("repository on the other end cannot be shallow"));
	oid_array_append(shallow_points, &old_oid);
	check_no_capabilities(line, len);
	return 1;
}

Project: git
File: connect.c

static int process_ref_v2(const char *line, struct ref ***list)
{
	int ret = 1;
	int i = 0;
	struct object_id old_oid;
	struct ref *ref;
	struct string_list line_sections = STRING_LIST_INIT_DUP;
	const char *end;

	/*
	 * Ref lines have a number of fields which are space deliminated.  The
	 * first field is the OID of the ref.  The second field is the ref
	 * name.  Subsequent fields (symref-target and peeled) are optional and
	 * don't have a particular order.
	 */
	if (string_list_split(&line_sections, line, ' ', -1) < 2) {
		ret = 0;
		goto out;
	}

	if (parse_oid_hex(line_sections.items[i++].string, &old_oid, &end) ||
	    *end) {
		ret = 0;
		goto out;
	}

	ref = alloc_ref(line_sections.items[i++].string);

	oidcpy(&ref->old_oid, &old_oid);
	**list = ref;
	*list = &ref->next;

	for (; i < line_sections.nr; i++) {
		const char *arg = line_sections.items[i].string;
		if (skip_prefix(arg, "symref-target:", &arg))
			ref->symref = xstrdup(arg);

		if (skip_prefix(arg, "peeled:", &arg)) {
			struct object_id peeled_oid;
			char *peeled_name;
			struct ref *peeled;
			if (parse_oid_hex(arg, &peeled_oid, &end) || *end) {
				ret = 0;
				goto out;
			}

			peeled_name = xstrfmt("%s^{}", ref->name);
			peeled = alloc_ref(peeled_name);

			oidcpy(&peeled->old_oid, &peeled_oid);
			**list = peeled;
			*list = &peeled->next;

			free(peeled_name);
		}
	}

out:
	string_list_clear(&line_sections, 0);
	return ret;
}

Project: git
File: connect.c

static struct child_process *git_connect_git(int fd[2], char *hostandport,
					     const char *path, const char *prog,
					     enum protocol_version version,
					     int flags)
{
	struct child_process *conn;
	struct strbuf request = STRBUF_INIT;
	/*
	 * Set up virtual host information based on where we will
	 * 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);

	transport_check_allowed("git");
	if (strchr(target_host, '\n') || strchr(path, '\n'))
		die(_("newline is forbidden in git:// hosts and repo paths"));

	/*
	 * These underlying connection commands die() if they
	 * cannot connect.
	 */
	if (git_use_proxy(hostandport))
		conn = git_proxy_connect(fd, hostandport);
	else
		conn = git_tcp_connect(fd, hostandport, flags);
	/*
	 * Separate original protocol components prog and path
	 * from extended host header with a NUL byte.
	 *
	 * Note: Do not add any other headers here!  Doing so
	 * will cause older git-daemon servers to crash.
	 */
	strbuf_addf(&request,
		    "%s %s%chost=%s%c",
		    prog, path, 0,
		    target_host, 0);

	/* If using a new version put that stuff here after a second null byte */
	if (version > 0) {
		strbuf_addch(&request, '\0');
		strbuf_addf(&request, "version=%d%c",
			    version, '\0');
	}

	packet_write(fd[1], request.buf, request.len);

	free(target_host);
	strbuf_release(&request);
	return conn;
}

Project: git
File: connect.c

static void fill_ssh_args(struct child_process *conn, const char *ssh_host,
			  const char *port, enum protocol_version version,
			  int flags)
{
	const char *ssh;
	enum ssh_variant variant;

	if (looks_like_command_line_option(ssh_host))
		die(_("strange hostname '%s' blocked"), ssh_host);

	ssh = get_ssh_command();
	if (ssh) {
		variant = determine_ssh_variant(ssh, 1);
	} else {
		/*
		 * 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";
		variant = determine_ssh_variant(ssh, 0);
	}

	if (variant == VARIANT_AUTO) {
		struct child_process detect = CHILD_PROCESS_INIT;

		detect.use_shell = conn->use_shell;
		detect.no_stdin = detect.no_stdout = detect.no_stderr = 1;

		argv_array_push(&detect.args, ssh);
		argv_array_push(&detect.args, "-G");
		push_ssh_options(&detect.args, &detect.env_array,
				 VARIANT_SSH, port, version, flags);
		argv_array_push(&detect.args, ssh_host);

		variant = run_command(&detect) ? VARIANT_SIMPLE : VARIANT_SSH;
	}

	argv_array_push(&conn->args, ssh);
	push_ssh_options(&conn->args, &conn->env_array, variant, port, version, flags);
	argv_array_push(&conn->args, ssh_host);
}

Project: git
File: connect.c

static void check_no_capabilities(const char *line, int len)
{
	if (strlen(line) != len)
		warning(_("ignoring capabilities after first line '%s'"),
			line + strlen(line));
}

Project: git
File: connect.c

int server_supports_feature(const char *c, const char *feature,
			    int die_on_error)
{
	int i;

	for (i = 0; i < server_capabilities_v2.argc; i++) {
		const char *out;
		if (skip_prefix(server_capabilities_v2.argv[i], c, &out) &&
		    (!*out || *(out++) == '=')) {
			if (parse_feature_request(out, feature))
				return 1;
			else
				break;
		}
	}

	if (die_on_error)
		die(_("server doesn't support feature '%s'"), feature);

	return 0;
}

Project: git
File: connect.c

struct ref **get_remote_refs(int fd_out, struct packet_reader *reader,
			     struct ref **list, int for_push,
			     const struct argv_array *ref_prefixes,
			     const struct string_list *server_options)
{
	int i;
	*list = NULL;

	if (server_supports_v2("ls-refs", 1))
		packet_write_fmt(fd_out, "command=ls-refs\n");

	if (server_supports_v2("agent", 0))
		packet_write_fmt(fd_out, "agent=%s", git_user_agent_sanitized());

	if (server_options && server_options->nr &&
	    server_supports_v2("server-option", 1))
		for (i = 0; i < server_options->nr; i++)
			packet_write_fmt(fd_out, "server-option=%s",
					 server_options->items[i].string);

	packet_delim(fd_out);
	/* When pushing we don't want to request the peeled tags */
	if (!for_push)
		packet_write_fmt(fd_out, "peel\n");
	packet_write_fmt(fd_out, "symrefs\n");
	for (i = 0; ref_prefixes && i < ref_prefixes->argc; i++) {
		packet_write_fmt(fd_out, "ref-prefix %s\n",
				 ref_prefixes->argv[i]);
	}
	packet_flush(fd_out);

	/* Process response from server */
	while (packet_reader_read(reader) == PACKET_READ_NORMAL) {
		if (!process_ref_v2(reader->line, &list))
			die(_("invalid ls-refs response: %s"), reader->line);
	}

	if (reader->status != PACKET_READ_FLUSH)
		die(_("expected flush after ref listing"));

	return list;
}

Project: git
File: connect.c

static void process_capabilities_v2(struct packet_reader *reader)
{
	while (packet_reader_read(reader) == PACKET_READ_NORMAL)
		argv_array_push(&server_capabilities_v2, reader->line);

	if (reader->status != PACKET_READ_FLUSH)
		die(_("expected flush after capabilities"));
}