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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.
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1 .\"

2 .\" Copyright (c) 2022 Stefan Sperling

3 .\"

4 .\" Permission to use, copy, modify, and distribute this software for any

5 .\" purpose with or without fee is hereby granted, provided that the above

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15 .\"

16 .Dd $Mdocdate$

17 .Dt GOTSH 1

18 .Os

19 .Sh NAME

20 .Nm gotsh

21 .Nd Game of Trees Shell

22 .Sh SYNOPSIS

23 .Nm Fl c Sq Cm git-receive-pack Ar repository-path

24 .Nm Fl c Sq Cm git-upload-pack Ar repository-path

25 .Sh DESCRIPTION

26 .Nm

27 is the network-facing interface to

28 .Xr gotd 8 .

29 It implements the server-side part of the Git network protocol used by

30 .Xr git 1

31 and

32 .Xr got 1 .

33 .Pp

34 .Nm

35 is not an interactive shell.

36 .Nm

37 is intended to be configured as the login shell of Git repository

38 user accounts on servers running

39 .Xr gotd 8 .

40 The users can then interact with

41 .Xr gotd 8

42 over the network.

43 When users invoke commands such as

44 .Cm got send

45 and

46 .Cm got fetch

47 on client machines,

48 .Xr got 1

49 will connect to the server with

50 .Xr ssh 1 .

51 .Nm

52 will facilitate communication between

53 .Xr gotd 8

54 running on the server machine and the

55 .Xr got 1

56 or

57 .Xr git 1

58 program running on the client machine.

59 .Pp

60 Users running

61 .Nm

62 must be members of the group which has read/write permission to the

63 .Xr gotd 8

64 unix socket.

65 The group used for this purpose can be configured in

66 .Xr gotd.conf 5 .

67 Users running

68 .Nm

69 should not have access to Git repositories by means other than

70 accessing the unix socket of

71 .Xr gotd 8

72 via

73 .Nm .

74 .Pp

75 It is recommended to restrict

76 .Xr ssh 1

77 features available to users of

78 .Nm .

79 See the EXAMPLES section for details.

80 .Sh ENVIRONMENT

81 .Bl -tag -width GOTD_UNIX_SOCKET

82 .It Ev GOTD_UNIX_SOCKET

83 Set the path to the unix socket which

84 .Xr gotd 8

85 is listening on.

86 If not specified, the default path

87 .Pa /var/run/gotd.sock

88 will be used.

89 .El

90 .Sh EXAMPLES

91 The following

92 .Xr sshd_config 5

93 directives are recommended to protect the server machine and any systems

94 reachable from it via

95 .Xr ssh 1

96 forwarding features.

97 This example assumes the group called

98 .Dq _gotsh

99 has read/write access to the

100 .Xr gotd 8

101 unix socket.

102 .Bd -literal -offset indent

103 Match Group _gotsh

104     DisableForwarding

105     PermitTTY no

106 .Sh SEE ALSO

107 .Xr got 1 ,

108 .Xr ssh 1 ,

109 .Xr gotd.conf 5 ,

110 .Xr sshd_config 5 ,

111 .Xr gotd 8

112 .Sh AUTHORS

113 .An Stefan Sperling Aq Mt stsp@openbsd.org