Gotweb

Blame

Date:: Sun Oct 23 14:38:32 2022 UTC
Message:: introduce gotd(8), a Git repository server reachable via ssh(1) This is an initial barebones implementation which provides the absolute minimum of functionality required to serve got(1) and git(1) clients. Basic fetch/send functionality has been tested and seems to work here, but this server is not yet expected to be stable. More testing is welcome. See the man pages for setup instructions. The current design uses one reader and one writer process per repository, which will have to be extended to N readers and N writers in the future. At startup, each process will chroot(2) into its assigned repository. This works because gotd(8) can only be started as root, and will then fork+exec, chroot, and privdrop. At present the parent process runs with the following pledge(2) promises: "stdio rpath wpath cpath proc getpw sendfd recvfd fattr flock unix unveil" The parent is the only process able to modify the repository in a way that becomes visible to Git clients. The parent uses unveil(2) to restrict its view of the filesystem to /tmp and the repositories listed in the configuration file gotd.conf(5). Per-repository chroot(2) processes use "stdio rpath sendfd recvfd". The writer defers to the parent for modifying references in the repository to point at newly uploaded commits. The reader is fine without such help, because Git repositories can be read without having to create any lock-files. gotd(8) requires a dedicated user ID, which should own repositories on the filesystem, and a separate secondary group, which should not have filesystem-level repository access, and must be allowed access to the gotd(8) socket. To obtain Git repository access, users must be members of this secondary group, and must have their login shell set to gotsh(1). gotsh(1) connects to the gotd(8) socket and speaks Git-protocol towards the client on the other end of the SSH connection. gotsh(1) is not an interactive command shell. At present, authenticated clients are granted read/write access to all repositories and all references (except for the "refs/got/" and the "refs/remotes/" namespaces, which are already being protected from modification). While complicated access control mechanism are not a design goal, making it possible to safely offer anonymous Git repository access over ssh(1) is on the road map.
Actions:: History | Blob | Raw File

  1 3efd8e31 2022-10-23 thomas /*
  2 3efd8e31 2022-10-23 thomas  * Copyright (c) 2018, 2022 Stefan Sperling <stsp@openbsd.org>
  3 3efd8e31 2022-10-23 thomas  *
  4 3efd8e31 2022-10-23 thomas  * Permission to use, copy, modify, and distribute this software for any
  5 3efd8e31 2022-10-23 thomas  * purpose with or without fee is hereby granted, provided that the above
  6 3efd8e31 2022-10-23 thomas  * copyright notice and this permission notice appear in all copies.
  7 3efd8e31 2022-10-23 thomas  *
  8 3efd8e31 2022-10-23 thomas  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  9 3efd8e31 2022-10-23 thomas  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 10 3efd8e31 2022-10-23 thomas  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 11 3efd8e31 2022-10-23 thomas  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 12 3efd8e31 2022-10-23 thomas  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 13 3efd8e31 2022-10-23 thomas  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 14 3efd8e31 2022-10-23 thomas  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 15 3efd8e31 2022-10-23 thomas  */
 16 3efd8e31 2022-10-23 thomas 
 17 3efd8e31 2022-10-23 thomas #include <errno.h>
 18 3efd8e31 2022-10-23 thomas #include <stdio.h>
 19 3efd8e31 2022-10-23 thomas #include <signal.h>
 20 3efd8e31 2022-10-23 thomas #include <poll.h>
 21 3efd8e31 2022-10-23 thomas #include <time.h>
 22 3efd8e31 2022-10-23 thomas #include <unistd.h>
 23 3efd8e31 2022-10-23 thomas 
 24 3efd8e31 2022-10-23 thomas #include "got_error.h"
 25 3efd8e31 2022-10-23 thomas 
 26 3efd8e31 2022-10-23 thomas #include "got_lib_poll.h"
 27 3efd8e31 2022-10-23 thomas 
 28 3efd8e31 2022-10-23 thomas const struct got_error *
 29 3efd8e31 2022-10-23 thomas got_poll_fd(int fd, int events, int timeout)
 30 3efd8e31 2022-10-23 thomas {
 31 3efd8e31 2022-10-23 thomas 	struct pollfd pfd[1];
 32 3efd8e31 2022-10-23 thomas 	struct timespec ts;
 33 3efd8e31 2022-10-23 thomas 	sigset_t sigset;
 34 3efd8e31 2022-10-23 thomas 	int n;
 35 3efd8e31 2022-10-23 thomas 
 36 3efd8e31 2022-10-23 thomas 	pfd[0].fd = fd;
 37 3efd8e31 2022-10-23 thomas 	pfd[0].events = events;
 38 3efd8e31 2022-10-23 thomas 
 39 3efd8e31 2022-10-23 thomas 	ts.tv_sec = timeout;
 40 3efd8e31 2022-10-23 thomas 	ts.tv_nsec = 0;
 41 3efd8e31 2022-10-23 thomas 
 42 3efd8e31 2022-10-23 thomas 	if (sigemptyset(&sigset) == -1)
 43 3efd8e31 2022-10-23 thomas 		return got_error_from_errno("sigemptyset");
 44 3efd8e31 2022-10-23 thomas 	if (sigaddset(&sigset, SIGWINCH) == -1)
 45 3efd8e31 2022-10-23 thomas 		return got_error_from_errno("sigaddset");
 46 3efd8e31 2022-10-23 thomas 
 47 3efd8e31 2022-10-23 thomas 	n = ppoll(pfd, 1, timeout == INFTIM ? NULL : &ts, &sigset);
 48 3efd8e31 2022-10-23 thomas 	if (n == -1)
 49 3efd8e31 2022-10-23 thomas 		return got_error_from_errno("ppoll");
 50 3efd8e31 2022-10-23 thomas 	if (n == 0) {
 51 3efd8e31 2022-10-23 thomas 		if (pfd[0].revents & POLLHUP)
 52 3efd8e31 2022-10-23 thomas 			return got_error(GOT_ERR_EOF);
 53 3efd8e31 2022-10-23 thomas 		return got_error(GOT_ERR_TIMEOUT);
 54 3efd8e31 2022-10-23 thomas 	}
 55 3efd8e31 2022-10-23 thomas 	if (pfd[0].revents & (POLLERR | POLLNVAL))
 56 3efd8e31 2022-10-23 thomas 		return got_error_from_errno("poll error");
 57 3efd8e31 2022-10-23 thomas 	if (pfd[0].revents & events)
 58 3efd8e31 2022-10-23 thomas 		return NULL;
 59 3efd8e31 2022-10-23 thomas 	if (pfd[0].revents & POLLHUP)
 60 3efd8e31 2022-10-23 thomas 		return got_error(GOT_ERR_EOF);
 61 3efd8e31 2022-10-23 thomas 
 62 3efd8e31 2022-10-23 thomas 	return got_error(GOT_ERR_INTERRUPT);
 63 3efd8e31 2022-10-23 thomas }
 64 3efd8e31 2022-10-23 thomas 
 65 3efd8e31 2022-10-23 thomas const struct got_error *
 66 3efd8e31 2022-10-23 thomas got_poll_read_full(int fd, size_t *len, void *buf, size_t bufsize,
 67 3efd8e31 2022-10-23 thomas     size_t minbytes)
 68 3efd8e31 2022-10-23 thomas {
 69 3efd8e31 2022-10-23 thomas 	const struct got_error *err = NULL;
 70 3efd8e31 2022-10-23 thomas 	size_t have = 0;
 71 3efd8e31 2022-10-23 thomas 	ssize_t r;
 72 3efd8e31 2022-10-23 thomas 
 73 3efd8e31 2022-10-23 thomas 	if (minbytes > bufsize)
 74 3efd8e31 2022-10-23 thomas 		return got_error(GOT_ERR_NO_SPACE);
 75 3efd8e31 2022-10-23 thomas 
 76 3efd8e31 2022-10-23 thomas 	while (have < minbytes) {
 77 3efd8e31 2022-10-23 thomas 		err = got_poll_fd(fd, POLLIN, INFTIM);
 78 3efd8e31 2022-10-23 thomas 		if (err)
 79 3efd8e31 2022-10-23 thomas 			return err;
 80 3efd8e31 2022-10-23 thomas 		r = read(fd, buf + have, bufsize - have);
 81 3efd8e31 2022-10-23 thomas 		if (r == -1)
 82 3efd8e31 2022-10-23 thomas 			return got_error_from_errno("read");
 83 3efd8e31 2022-10-23 thomas 		if (r == 0)
 84 3efd8e31 2022-10-23 thomas 			return got_error(GOT_ERR_EOF);
 85 3efd8e31 2022-10-23 thomas 		have += r;
 86 3efd8e31 2022-10-23 thomas 	}
 87 3efd8e31 2022-10-23 thomas 
 88 3efd8e31 2022-10-23 thomas 	*len = have;
 89 3efd8e31 2022-10-23 thomas 	return NULL;
 90 3efd8e31 2022-10-23 thomas }
 91 3efd8e31 2022-10-23 thomas 
 92 3efd8e31 2022-10-23 thomas const struct got_error *
 93 3efd8e31 2022-10-23 thomas got_poll_write_full(int fd, const void *buf, off_t len)
 94 3efd8e31 2022-10-23 thomas {
 95 3efd8e31 2022-10-23 thomas 	const struct got_error *err = NULL;
 96 3efd8e31 2022-10-23 thomas 	off_t wlen = 0;
 97 3efd8e31 2022-10-23 thomas 	ssize_t w = 0;
 98 3efd8e31 2022-10-23 thomas 
 99 3efd8e31 2022-10-23 thomas 	while (wlen != len) {
100 3efd8e31 2022-10-23 thomas 		if (wlen > 0) {
101 3efd8e31 2022-10-23 thomas 			err = got_poll_fd(fd, POLLOUT, INFTIM);
102 3efd8e31 2022-10-23 thomas 			if (err)
103 3efd8e31 2022-10-23 thomas 				return err;
104 3efd8e31 2022-10-23 thomas 		}
105 3efd8e31 2022-10-23 thomas 		w = write(fd, buf + wlen, len - wlen);
106 3efd8e31 2022-10-23 thomas 		if (w == -1) {
107 3efd8e31 2022-10-23 thomas 			if (errno != EAGAIN)
108 3efd8e31 2022-10-23 thomas 				return got_error_from_errno("write");
109 3efd8e31 2022-10-23 thomas 		} else
110 3efd8e31 2022-10-23 thomas 			wlen += w;
111 3efd8e31 2022-10-23 thomas 	}
112 3efd8e31 2022-10-23 thomas 
113 3efd8e31 2022-10-23 thomas 	return NULL;
114 3efd8e31 2022-10-23 thomas }