Revision b0e3e2d06ba3b71079d7b9b6402a0f410180c09b authored by Jeff King on 17 January 2023, 03:04:44 UTC, committed by Johannes Schindelin on 12 March 2023, 19:31:54 UTC
The IOCTLFUNCTION option has been deprecated, and generates a compiler
warning in recent versions of curl. We can switch to using SEEKFUNCTION
instead. It was added in 2008 via curl 7.18.0; our INSTALL file already
indicates we require at least curl 7.19.4.

But there's one catch: curl says we should use CURL_SEEKFUNC_{OK,FAIL},
and those didn't arrive until 7.19.5. One workaround would be to use a
bare 0/1 here (or define our own macros).  But let's just bump the
minimum required version to 7.19.5. That version is only a minor version
bump from our existing requirement, and is only a 2 month time bump for
versions that are almost 13 years old. So it's not likely that anybody
cares about the distinction.

Switching means we have to rewrite the ioctl functions into seek
functions. In some ways they are simpler (seeking is the only
operation), but in some ways more complex (the ioctl allowed only a full
rewind, but now we can seek to arbitrary offsets).

Curl will only ever use SEEK_SET (per their documentation), so I didn't
bother implementing anything else, since it would naturally be
completely untested. This seems unlikely to change, but I added an
assertion just in case.

Likewise, I doubt curl will ever try to seek outside of the buffer sizes
we've told it, but I erred on the defensive side here, rather than do an
out-of-bounds read.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
1 parent fda237c
Raw File
send-pack.c
#include "builtin.h"
#include "config.h"
#include "commit.h"
#include "refs.h"
#include "object-store.h"
#include "pkt-line.h"
#include "sideband.h"
#include "run-command.h"
#include "remote.h"
#include "connect.h"
#include "send-pack.h"
#include "quote.h"
#include "transport.h"
#include "version.h"
#include "oid-array.h"
#include "gpg-interface.h"
#include "cache.h"
#include "shallow.h"

int option_parse_push_signed(const struct option *opt,
			     const char *arg, int unset)
{
	if (unset) {
		*(int *)(opt->value) = SEND_PACK_PUSH_CERT_NEVER;
		return 0;
	}
	switch (git_parse_maybe_bool(arg)) {
	case 1:
		*(int *)(opt->value) = SEND_PACK_PUSH_CERT_ALWAYS;
		return 0;
	case 0:
		*(int *)(opt->value) = SEND_PACK_PUSH_CERT_NEVER;
		return 0;
	}
	if (!strcasecmp("if-asked", arg)) {
		*(int *)(opt->value) = SEND_PACK_PUSH_CERT_IF_ASKED;
		return 0;
	}
	die("bad %s argument: %s", opt->long_name, arg);
}

static void feed_object(const struct object_id *oid, FILE *fh, int negative)
{
	if (negative &&
	    !has_object_file_with_flags(oid,
					OBJECT_INFO_SKIP_FETCH_OBJECT |
					OBJECT_INFO_QUICK))
		return;

	if (negative)
		putc('^', fh);
	fputs(oid_to_hex(oid), fh);
	putc('\n', fh);
}

/*
 * Make a pack stream and spit it out into file descriptor fd
 */
static int pack_objects(int fd, struct ref *refs, struct oid_array *extra, struct send_pack_args *args)
{
	/*
	 * The child becomes pack-objects --revs; we feed
	 * the revision parameters to it via its stdin and
	 * let its stdout go back to the other end.
	 */
	struct child_process po = CHILD_PROCESS_INIT;
	FILE *po_in;
	int i;
	int rc;

	strvec_push(&po.args, "pack-objects");
	strvec_push(&po.args, "--all-progress-implied");
	strvec_push(&po.args, "--revs");
	strvec_push(&po.args, "--stdout");
	if (args->use_thin_pack)
		strvec_push(&po.args, "--thin");
	if (args->use_ofs_delta)
		strvec_push(&po.args, "--delta-base-offset");
	if (args->quiet || !args->progress)
		strvec_push(&po.args, "-q");
	if (args->progress)
		strvec_push(&po.args, "--progress");
	if (is_repository_shallow(the_repository))
		strvec_push(&po.args, "--shallow");
	po.in = -1;
	po.out = args->stateless_rpc ? -1 : fd;
	po.git_cmd = 1;
	po.clean_on_exit = 1;
	if (start_command(&po))
		die_errno("git pack-objects failed");

	/*
	 * We feed the pack-objects we just spawned with revision
	 * parameters by writing to the pipe.
	 */
	po_in = xfdopen(po.in, "w");
	for (i = 0; i < extra->nr; i++)
		feed_object(&extra->oid[i], po_in, 1);

	while (refs) {
		if (!is_null_oid(&refs->old_oid))
			feed_object(&refs->old_oid, po_in, 1);
		if (!is_null_oid(&refs->new_oid))
			feed_object(&refs->new_oid, po_in, 0);
		refs = refs->next;
	}

	fflush(po_in);
	if (ferror(po_in))
		die_errno("error writing to pack-objects");
	fclose(po_in);

	if (args->stateless_rpc) {
		char *buf = xmalloc(LARGE_PACKET_MAX);
		while (1) {
			ssize_t n = xread(po.out, buf, LARGE_PACKET_MAX);
			if (n <= 0)
				break;
			send_sideband(fd, -1, buf, n, LARGE_PACKET_MAX);
		}
		free(buf);
		close(po.out);
		po.out = -1;
	}

	rc = finish_command(&po);
	if (rc) {
		/*
		 * For a normal non-zero exit, we assume pack-objects wrote
		 * something useful to stderr. For death by signal, though,
		 * we should mention it to the user. The exception is SIGPIPE
		 * (141), because that's a normal occurrence if the remote end
		 * hangs up (and we'll report that by trying to read the unpack
		 * status).
		 */
		if (rc > 128 && rc != 141)
			error("pack-objects died of signal %d", rc - 128);
		return -1;
	}
	return 0;
}

static int receive_unpack_status(struct packet_reader *reader)
{
	if (packet_reader_read(reader) != PACKET_READ_NORMAL)
		return error(_("unexpected flush packet while reading remote unpack status"));
	if (!skip_prefix(reader->line, "unpack ", &reader->line))
		return error(_("unable to parse remote unpack status: %s"), reader->line);
	if (strcmp(reader->line, "ok"))
		return error(_("remote unpack failed: %s"), reader->line);
	return 0;
}

static int receive_status(struct packet_reader *reader, struct ref *refs)
{
	struct ref *hint;
	int ret;
	struct ref_push_report *report = NULL;
	int new_report = 0;
	int once = 0;

	hint = NULL;
	ret = receive_unpack_status(reader);
	while (1) {
		struct object_id old_oid, new_oid;
		const char *head;
		const char *refname;
		char *p;
		if (packet_reader_read(reader) != PACKET_READ_NORMAL)
			break;
		head = reader->line;
		p = strchr(head, ' ');
		if (!p) {
			error("invalid status line from remote: %s", reader->line);
			ret = -1;
			break;
		}
		*p++ = '\0';

		if (!strcmp(head, "option")) {
			const char *key, *val;

			if (!hint || !(report || new_report)) {
				if (!once++)
					error("'option' without a matching 'ok/ng' directive");
				ret = -1;
				continue;
			}
			if (new_report) {
				if (!hint->report) {
					hint->report = xcalloc(1, sizeof(struct ref_push_report));
					report = hint->report;
				} else {
					report = hint->report;
					while (report->next)
						report = report->next;
					report->next = xcalloc(1, sizeof(struct ref_push_report));
					report = report->next;
				}
				new_report = 0;
			}
			key = p;
			p = strchr(key, ' ');
			if (p)
				*p++ = '\0';
			val = p;
			if (!strcmp(key, "refname"))
				report->ref_name = xstrdup_or_null(val);
			else if (!strcmp(key, "old-oid") && val &&
				 !parse_oid_hex(val, &old_oid, &val))
				report->old_oid = oiddup(&old_oid);
			else if (!strcmp(key, "new-oid") && val &&
				 !parse_oid_hex(val, &new_oid, &val))
				report->new_oid = oiddup(&new_oid);
			else if (!strcmp(key, "forced-update"))
				report->forced_update = 1;
			continue;
		}

		report = NULL;
		new_report = 0;
		if (strcmp(head, "ok") && strcmp(head, "ng")) {
			error("invalid ref status from remote: %s", head);
			ret = -1;
			break;
		}
		refname = p;
		p = strchr(refname, ' ');
		if (p)
			*p++ = '\0';
		/* first try searching at our hint, falling back to all refs */
		if (hint)
			hint = find_ref_by_name(hint, refname);
		if (!hint)
			hint = find_ref_by_name(refs, refname);
		if (!hint) {
			warning("remote reported status on unknown ref: %s",
				refname);
			continue;
		}
		if (hint->status != REF_STATUS_EXPECTING_REPORT &&
		    hint->status != REF_STATUS_OK &&
		    hint->status != REF_STATUS_REMOTE_REJECT) {
			warning("remote reported status on unexpected ref: %s",
				refname);
			continue;
		}
		if (!strcmp(head, "ng")) {
			hint->status = REF_STATUS_REMOTE_REJECT;
			if (p)
				hint->remote_status = xstrdup(p);
			else
				hint->remote_status = "failed";
		} else {
			hint->status = REF_STATUS_OK;
			hint->remote_status = xstrdup_or_null(p);
			new_report = 1;
		}
	}
	return ret;
}

static int sideband_demux(int in, int out, void *data)
{
	int *fd = data, ret;
	if (async_with_fork())
		close(fd[1]);
	ret = recv_sideband("send-pack", fd[0], out);
	close(out);
	return ret;
}

static int advertise_shallow_grafts_cb(const struct commit_graft *graft, void *cb)
{
	struct strbuf *sb = cb;
	if (graft->nr_parent == -1)
		packet_buf_write(sb, "shallow %s\n", oid_to_hex(&graft->oid));
	return 0;
}

static void advertise_shallow_grafts_buf(struct strbuf *sb)
{
	if (!is_repository_shallow(the_repository))
		return;
	for_each_commit_graft(advertise_shallow_grafts_cb, sb);
}

#define CHECK_REF_NO_PUSH -1
#define CHECK_REF_STATUS_REJECTED -2
#define CHECK_REF_UPTODATE -3
static int check_to_send_update(const struct ref *ref, const struct send_pack_args *args)
{
	if (!ref->peer_ref && !args->send_mirror)
		return CHECK_REF_NO_PUSH;

	/* Check for statuses set by set_ref_status_for_push() */
	switch (ref->status) {
	case REF_STATUS_REJECT_NONFASTFORWARD:
	case REF_STATUS_REJECT_ALREADY_EXISTS:
	case REF_STATUS_REJECT_FETCH_FIRST:
	case REF_STATUS_REJECT_NEEDS_FORCE:
	case REF_STATUS_REJECT_STALE:
	case REF_STATUS_REJECT_REMOTE_UPDATED:
	case REF_STATUS_REJECT_NODELETE:
		return CHECK_REF_STATUS_REJECTED;
	case REF_STATUS_UPTODATE:
		return CHECK_REF_UPTODATE;

	default:
	case REF_STATUS_EXPECTING_REPORT:
		/* already passed checks on the local side */
	case REF_STATUS_OK:
		/* of course this is OK */
		return 0;
	}
}

/*
 * the beginning of the next line, or the end of buffer.
 *
 * NEEDSWORK: perhaps move this to git-compat-util.h or somewhere and
 * convert many similar uses found by "git grep -A4 memchr".
 */
static const char *next_line(const char *line, size_t len)
{
	const char *nl = memchr(line, '\n', len);
	if (!nl)
		return line + len; /* incomplete line */
	return nl + 1;
}

static int generate_push_cert(struct strbuf *req_buf,
			      const struct ref *remote_refs,
			      struct send_pack_args *args,
			      const char *cap_string,
			      const char *push_cert_nonce)
{
	const struct ref *ref;
	struct string_list_item *item;
	char *signing_key = xstrdup(get_signing_key());
	const char *cp, *np;
	struct strbuf cert = STRBUF_INIT;
	int update_seen = 0;

	strbuf_addstr(&cert, "certificate version 0.1\n");
	strbuf_addf(&cert, "pusher %s ", signing_key);
	datestamp(&cert);
	strbuf_addch(&cert, '\n');
	if (args->url && *args->url) {
		char *anon_url = transport_anonymize_url(args->url);
		strbuf_addf(&cert, "pushee %s\n", anon_url);
		free(anon_url);
	}
	if (push_cert_nonce[0])
		strbuf_addf(&cert, "nonce %s\n", push_cert_nonce);
	if (args->push_options)
		for_each_string_list_item(item, args->push_options)
			strbuf_addf(&cert, "push-option %s\n", item->string);
	strbuf_addstr(&cert, "\n");

	for (ref = remote_refs; ref; ref = ref->next) {
		if (check_to_send_update(ref, args) < 0)
			continue;
		update_seen = 1;
		strbuf_addf(&cert, "%s %s %s\n",
			    oid_to_hex(&ref->old_oid),
			    oid_to_hex(&ref->new_oid),
			    ref->name);
	}
	if (!update_seen)
		goto free_return;

	if (sign_buffer(&cert, &cert, signing_key))
		die(_("failed to sign the push certificate"));

	packet_buf_write(req_buf, "push-cert%c%s", 0, cap_string);
	for (cp = cert.buf; cp < cert.buf + cert.len; cp = np) {
		np = next_line(cp, cert.buf + cert.len - cp);
		packet_buf_write(req_buf,
				 "%.*s", (int)(np - cp), cp);
	}
	packet_buf_write(req_buf, "push-cert-end\n");

free_return:
	free(signing_key);
	strbuf_release(&cert);
	return update_seen;
}

#define NONCE_LEN_LIMIT 256

static void reject_invalid_nonce(const char *nonce, int len)
{
	int i = 0;

	if (NONCE_LEN_LIMIT <= len)
		die("the receiving end asked to sign an invalid nonce <%.*s>",
		    len, nonce);

	for (i = 0; i < len; i++) {
		int ch = nonce[i] & 0xFF;
		if (isalnum(ch) ||
		    ch == '-' || ch == '.' ||
		    ch == '/' || ch == '+' ||
		    ch == '=' || ch == '_')
			continue;
		die("the receiving end asked to sign an invalid nonce <%.*s>",
		    len, nonce);
	}
}

int send_pack(struct send_pack_args *args,
	      int fd[], struct child_process *conn,
	      struct ref *remote_refs,
	      struct oid_array *extra_have)
{
	int in = fd[0];
	int out = fd[1];
	struct strbuf req_buf = STRBUF_INIT;
	struct strbuf cap_buf = STRBUF_INIT;
	struct ref *ref;
	int need_pack_data = 0;
	int allow_deleting_refs = 0;
	int status_report = 0;
	int use_sideband = 0;
	int quiet_supported = 0;
	int agent_supported = 0;
	int advertise_sid = 0;
	int use_atomic = 0;
	int atomic_supported = 0;
	int use_push_options = 0;
	int push_options_supported = 0;
	int object_format_supported = 0;
	unsigned cmds_sent = 0;
	int ret;
	struct async demux;
	const char *push_cert_nonce = NULL;
	struct packet_reader reader;

	git_config_get_bool("transfer.advertisesid", &advertise_sid);

	/* Does the other end support the reporting? */
	if (server_supports("report-status-v2"))
		status_report = 2;
	else if (server_supports("report-status"))
		status_report = 1;
	if (server_supports("delete-refs"))
		allow_deleting_refs = 1;
	if (server_supports("ofs-delta"))
		args->use_ofs_delta = 1;
	if (server_supports("side-band-64k"))
		use_sideband = 1;
	if (server_supports("quiet"))
		quiet_supported = 1;
	if (server_supports("agent"))
		agent_supported = 1;
	if (!server_supports("session-id"))
		advertise_sid = 0;
	if (server_supports("no-thin"))
		args->use_thin_pack = 0;
	if (server_supports("atomic"))
		atomic_supported = 1;
	if (server_supports("push-options"))
		push_options_supported = 1;

	if (!server_supports_hash(the_hash_algo->name, &object_format_supported))
		die(_("the receiving end does not support this repository's hash algorithm"));

	if (args->push_cert != SEND_PACK_PUSH_CERT_NEVER) {
		int len;
		push_cert_nonce = server_feature_value("push-cert", &len);
		if (push_cert_nonce) {
			reject_invalid_nonce(push_cert_nonce, len);
			push_cert_nonce = xmemdupz(push_cert_nonce, len);
		} else if (args->push_cert == SEND_PACK_PUSH_CERT_ALWAYS) {
			die(_("the receiving end does not support --signed push"));
		} else if (args->push_cert == SEND_PACK_PUSH_CERT_IF_ASKED) {
			warning(_("not sending a push certificate since the"
				  " receiving end does not support --signed"
				  " push"));
		}
	}

	if (!remote_refs) {
		fprintf(stderr, "No refs in common and none specified; doing nothing.\n"
			"Perhaps you should specify a branch.\n");
		return 0;
	}
	if (args->atomic && !atomic_supported)
		die(_("the receiving end does not support --atomic push"));

	use_atomic = atomic_supported && args->atomic;

	if (args->push_options && !push_options_supported)
		die(_("the receiving end does not support push options"));

	use_push_options = push_options_supported && args->push_options;

	if (status_report == 1)
		strbuf_addstr(&cap_buf, " report-status");
	else if (status_report == 2)
		strbuf_addstr(&cap_buf, " report-status-v2");
	if (use_sideband)
		strbuf_addstr(&cap_buf, " side-band-64k");
	if (quiet_supported && (args->quiet || !args->progress))
		strbuf_addstr(&cap_buf, " quiet");
	if (use_atomic)
		strbuf_addstr(&cap_buf, " atomic");
	if (use_push_options)
		strbuf_addstr(&cap_buf, " push-options");
	if (object_format_supported)
		strbuf_addf(&cap_buf, " object-format=%s", the_hash_algo->name);
	if (agent_supported)
		strbuf_addf(&cap_buf, " agent=%s", git_user_agent_sanitized());
	if (advertise_sid)
		strbuf_addf(&cap_buf, " session-id=%s", trace2_session_id());

	/*
	 * NEEDSWORK: why does delete-refs have to be so specific to
	 * send-pack machinery that set_ref_status_for_push() cannot
	 * set this bit for us???
	 */
	for (ref = remote_refs; ref; ref = ref->next)
		if (ref->deletion && !allow_deleting_refs)
			ref->status = REF_STATUS_REJECT_NODELETE;

	/*
	 * Clear the status for each ref and see if we need to send
	 * the pack data.
	 */
	for (ref = remote_refs; ref; ref = ref->next) {
		switch (check_to_send_update(ref, args)) {
		case 0: /* no error */
			break;
		case CHECK_REF_STATUS_REJECTED:
			/*
			 * When we know the server would reject a ref update if
			 * we were to send it and we're trying to send the refs
			 * atomically, abort the whole operation.
			 */
			if (use_atomic) {
				strbuf_release(&req_buf);
				strbuf_release(&cap_buf);
				reject_atomic_push(remote_refs, args->send_mirror);
				error("atomic push failed for ref %s. status: %d\n",
				      ref->name, ref->status);
				return args->porcelain ? 0 : -1;
			}
			/* else fallthrough */
		default:
			continue;
		}
		if (!ref->deletion)
			need_pack_data = 1;

		if (args->dry_run || !status_report)
			ref->status = REF_STATUS_OK;
		else
			ref->status = REF_STATUS_EXPECTING_REPORT;
	}

	if (!args->dry_run)
		advertise_shallow_grafts_buf(&req_buf);

	/*
	 * Finally, tell the other end!
	 */
	if (!args->dry_run && push_cert_nonce)
		cmds_sent = generate_push_cert(&req_buf, remote_refs, args,
					       cap_buf.buf, push_cert_nonce);
	else if (!args->dry_run)
		for (ref = remote_refs; ref; ref = ref->next) {
			char *old_hex, *new_hex;

			if (check_to_send_update(ref, args) < 0)
				continue;

			old_hex = oid_to_hex(&ref->old_oid);
			new_hex = oid_to_hex(&ref->new_oid);
			if (!cmds_sent) {
				packet_buf_write(&req_buf,
						 "%s %s %s%c%s",
						 old_hex, new_hex, ref->name, 0,
						 cap_buf.buf);
				cmds_sent = 1;
			} else {
				packet_buf_write(&req_buf, "%s %s %s",
						 old_hex, new_hex, ref->name);
			}
		}

	if (use_push_options) {
		struct string_list_item *item;

		packet_buf_flush(&req_buf);
		for_each_string_list_item(item, args->push_options)
			packet_buf_write(&req_buf, "%s", item->string);
	}

	if (args->stateless_rpc) {
		if (!args->dry_run && (cmds_sent || is_repository_shallow(the_repository))) {
			packet_buf_flush(&req_buf);
			send_sideband(out, -1, req_buf.buf, req_buf.len, LARGE_PACKET_MAX);
		}
	} else {
		write_or_die(out, req_buf.buf, req_buf.len);
		packet_flush(out);
	}
	strbuf_release(&req_buf);
	strbuf_release(&cap_buf);

	if (use_sideband && cmds_sent) {
		memset(&demux, 0, sizeof(demux));
		demux.proc = sideband_demux;
		demux.data = fd;
		demux.out = -1;
		demux.isolate_sigpipe = 1;
		if (start_async(&demux))
			die("send-pack: unable to fork off sideband demultiplexer");
		in = demux.out;
	}

	packet_reader_init(&reader, in, NULL, 0,
			   PACKET_READ_CHOMP_NEWLINE |
			   PACKET_READ_DIE_ON_ERR_PACKET);

	if (need_pack_data && cmds_sent) {
		if (pack_objects(out, remote_refs, extra_have, args) < 0) {
			if (args->stateless_rpc)
				close(out);
			if (git_connection_is_socket(conn))
				shutdown(fd[0], SHUT_WR);

			/*
			 * Do not even bother with the return value; we know we
			 * are failing, and just want the error() side effects,
			 * as well as marking refs with their remote status (if
			 * we get one).
			 */
			if (status_report)
				receive_status(&reader, remote_refs);

			if (use_sideband) {
				close(demux.out);
				finish_async(&demux);
			}
			fd[1] = -1;
			return -1;
		}
		if (!args->stateless_rpc)
			/* Closed by pack_objects() via start_command() */
			fd[1] = -1;
	}
	if (args->stateless_rpc && cmds_sent)
		packet_flush(out);

	if (status_report && cmds_sent)
		ret = receive_status(&reader, remote_refs);
	else
		ret = 0;
	if (args->stateless_rpc)
		packet_flush(out);

	if (use_sideband && cmds_sent) {
		close(demux.out);
		if (finish_async(&demux)) {
			error("error in sideband demultiplexer");
			ret = -1;
		}
	}

	if (ret < 0)
		return ret;

	if (args->porcelain)
		return 0;

	for (ref = remote_refs; ref; ref = ref->next) {
		switch (ref->status) {
		case REF_STATUS_NONE:
		case REF_STATUS_UPTODATE:
		case REF_STATUS_OK:
			break;
		default:
			return -1;
		}
	}
	return 0;
}
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