# Gforge's cvssh.pl script and git 4 messages from 2009-02-18 to 2009-02-18. Participants: Bosko Ivanisevic, Johannes Schindelin. Thread: https://gitlist.dev/t/17872 ## Bosko Ivanisevic, 2009-02-18 09:24 Subject: Gforge's cvssh.pl script and git Message-ID: <2c0671440902180124v50570270gc40b745d4a8b1245@mail.gmail.com> URL: https://gitlist.dev/e/2c0671440902180124v50570270gc40b745d4a8b1245%40mail.gmail.com ``` In the company I'm working someone has restricted access to all users to only use cvs via cvssh.pl script (source at the end of message) taken from gforge. This script is set as a shell for all users. Now I would like to change it so I can run git too. I've tried by adding 'git', 'git-upload-pack', 'git-receive-pack' and 'git-shell' in the array @allowed_commands. After that if I try to clone existing repository with: git clone ssh://testuser@server_name/tmp/test.git I get following error: fatal: ''/tmp/test.git'': unable to chdir or not a git archive fatal: The remote end hung up unexpectedly I first thought that testuser doesn't have permissions to read directory /tmp/test.git so I changed mode and gave r+w permissions recursively on that folder, but result was same. There is no way I can avoid this perl script (company policy) but I can change it. Problem is that I do not know Perl so much and I do not know what git is exactly doing behind the scene when it is run via ssh. Can anyone tell me why this perl script doesn't allow git to run properly and what has to be changed to enable git? #! /usr/bin/perl -w # # $Id: cvssh.pl 3987 2005-02-26 22:59:11Z tperdue $ # # "Shell" for a restricted account, limiting the available commands # Roland Mas, debian-sf (Sourceforge for Debian) # # Inspired from the grap.c file in Sourceforge 2.5 use strict ; use vars qw/ @allowed_options @allowed_commands $errmsg @cmd / ; use subs qw/ &reject / ; no locale ; @allowed_options = ('-c', '-e') ; @allowed_commands = ('cvs') ; # Clean up our environment delete @ENV{qw(IFS CDPATH ENV BASH_ENV PATH)}; @cmd = split (/ +/, $ENV{SSH_CLIENT}); if (scalar (grep {/192.168.0/} @cmd) == 0) { $errmsg = "Client address not allowed." ; &reject ; } if ($#ARGV != 1) { if ($#ARGV < 1) { $errmsg = "Not enough arguments." ; } else { $errmsg = "Too many arguments." ; } &reject ; } if (scalar (grep { $_ eq $ARGV[0] } @allowed_options) == 0) { $errmsg = "Option not allowed." ; &reject ; } @cmd = split (/ +/, $ARGV[1]) ; if (scalar (grep { $_ eq $cmd[0] } @allowed_commands) == 0) { $errmsg = "Command not allowed." ; &reject ; } exec @cmd ; sub reject { print "This is a restricted account.\n" . "You cannot execute anything here.\n" . # $errmsg . "\n" . "Goodbye.\n" ; exit 1 ; } ``` ## Johannes Schindelin, 2009-02-18 13:24 Subject: Re: Gforge's cvssh.pl script and git Message-ID: URL: https://gitlist.dev/e/alpine.DEB.1.00.0902181417510.6274%40intel-tinevez-2-302 In-Reply-To: <2c0671440902180124v50570270gc40b745d4a8b1245@mail.gmail.com> ``` Hi, On Wed, 18 Feb 2009, Bosko Ivanisevic wrote: > In the company I'm working someone has restricted access to all users > to only use cvs via cvssh.pl script (source at the end of message) > taken from gforge. This script is set as a shell for all users. Now I > would like to change it so I can run git too. I've tried by adding > 'git', 'git-upload-pack', 'git-receive-pack' and 'git-shell' in the > array @allowed_commands. After that if I try to clone existing > repository with: > > git clone ssh://testuser@server_name/tmp/test.git > > I get following error: > > fatal: ''/tmp/test.git'': unable to chdir or not a git archive > fatal: The remote end hung up unexpectedly > > I first thought that testuser doesn't have permissions to read > directory /tmp/test.git so I changed mode and gave r+w permissions > recursively on that folder, but result was same. r+w? Not a+rwx? And only on /tmp/test.git/, or also on /tmp/? A better way would be to use 'sudo -u testuser git ls-remote /tmp/test.git' if sudo is available (you haven't revealed useful information about the host). > There is no way I can avoid this perl script (company policy) but I > can change it. Problem is that I do not know Perl so much and I do not > know what git is exactly doing behind the scene when it is run via > ssh. I'd use 'system("some shell >&2");' to try to debug it. Hth, Dscho ``` ## Bosko Ivanisevic, 2009-02-18 14:31 Subject: Re: Gforge's cvssh.pl script and git Message-ID: <2c0671440902180631lbf08d5egb003082a3c683f62@mail.gmail.com> URL: https://gitlist.dev/e/2c0671440902180631lbf08d5egb003082a3c683f62%40mail.gmail.com In-Reply-To: ``` Hi, On Wed, Feb 18, 2009 at 2:24 PM, Johannes Schindelin wrote: > Hi, > > On Wed, 18 Feb 2009, Bosko Ivanisevic wrote: > >> In the company I'm working someone has restricted access to all users >> to only use cvs via cvssh.pl script (source at the end of message) >> taken from gforge. This script is set as a shell for all users. Now I >> would like to change it so I can run git too. I've tried by adding >> 'git', 'git-upload-pack', 'git-receive-pack' and 'git-shell' in the >> array @allowed_commands. After that if I try to clone existing >> repository with: >> >> git clone ssh://testuser@server_name/tmp/test.git >> >> I get following error: >> >> fatal: ''/tmp/test.git'': unable to chdir or not a git archive >> fatal: The remote end hung up unexpectedly >> >> I first thought that testuser doesn't have permissions to read >> directory /tmp/test.git so I changed mode and gave r+w permissions >> recursively on that folder, but result was same. > > r+w? Not a+rwx? > > And only on /tmp/test.git/, or also on /tmp/? > > A better way would be to use 'sudo -u testuser git ls-remote > /tmp/test.git' if sudo is available (you haven't revealed useful > information about the host). > Thanks for your reply. Here are more data. System is SuSe 10.3. On the test server which has same setup but I can change shell when I change testuser's shell to /bin/bash I can regularly clone git repository from remote machine, so all permissions are set correctly. Besides, output of: git ls-remote ssh://testuser@server_name:/tmp/test.git is: 3446c5347e0563cb87e1d8951c57b7f36996f44b HEAD 3446c5347e0563cb87e1d8951c57b7f36996f44b refs/heads/master That leads me to conclusion that perl's exec command makes some mess which prevents git of running correctly. >> There is no way I can avoid this perl script (company policy) but I >> can change it. Problem is that I do not know Perl so much and I do not >> know what git is exactly doing behind the scene when it is run via >> ssh. > > I'd use 'system("some shell >&2");' to try to debug it. > I didn't understand this part. If I change exec @cmd; command from perl script to: system("/bin/bash >&2); git clone just hangs on the client side. I guess I did something wrong but don't know what. Regards, Bosko ``` ## Johannes Schindelin, 2009-02-18 14:49 Subject: Re: Gforge's cvssh.pl script and git Message-ID: URL: https://gitlist.dev/e/alpine.DEB.1.00.0902181547240.6274%40intel-tinevez-2-302 In-Reply-To: <2c0671440902180631lbf08d5egb003082a3c683f62@mail.gmail.com> ``` Hi, On Wed, 18 Feb 2009, Bosko Ivanisevic wrote: > On Wed, Feb 18, 2009 at 2:24 PM, Johannes Schindelin > wrote: > > > On Wed, 18 Feb 2009, Bosko Ivanisevic wrote: > > > >> In the company I'm working someone has restricted access to all users > >> to only use cvs via cvssh.pl script (source at the end of message) > >> taken from gforge. This script is set as a shell for all users. Now I > >> would like to change it so I can run git too. I've tried by adding > >> 'git', 'git-upload-pack', 'git-receive-pack' and 'git-shell' in the > >> array @allowed_commands. After that if I try to clone existing > >> repository with: > >> > >> git clone ssh://testuser@server_name/tmp/test.git > >> > >> I get following error: > >> > >> fatal: ''/tmp/test.git'': unable to chdir or not a git archive > >> fatal: The remote end hung up unexpectedly > >> > >> I first thought that testuser doesn't have permissions to read > >> directory /tmp/test.git so I changed mode and gave r+w permissions > >> recursively on that folder, but result was same. > > > > r+w? Not a+rwx? > > > > And only on /tmp/test.git/, or also on /tmp/? > > > > A better way would be to use 'sudo -u testuser git ls-remote > > /tmp/test.git' if sudo is available (you haven't revealed useful > > information about the host). > > Thanks for your reply. Here are more data. System is SuSe 10.3. On the > test server which has same setup but I can change shell when I change > testuser's shell to /bin/bash I can regularly clone git repository from > remote machine, so all permissions are set correctly. Besides, output > of: > > git ls-remote ssh://testuser@server_name:/tmp/test.git > > is: > > 3446c5347e0563cb87e1d8951c57b7f36996f44b HEAD > 3446c5347e0563cb87e1d8951c57b7f36996f44b refs/heads/master > > That leads me to conclusion that perl's exec command makes some mess > which prevents git of running correctly. Maybe. Maybe it is also unsetting ENV which causes grief. > >> There is no way I can avoid this perl script (company policy) but I > >> can change it. Problem is that I do not know Perl so much and I do > >> not know what git is exactly doing behind the scene when it is run > >> via ssh. > > > > I'd use 'system("some shell >&2");' to try to debug it. > > > I didn't understand this part. If I change > > exec @cmd; > > command from perl script to: > > system("/bin/bash >&2); > > git clone just hangs on the client side. I guess I did something wrong > but don't know what. I did not mean to replace the exec. Rather, I meant you could do something like system('ls -l /tmp/test.git >&2'); to see what is actually happening. I mean, it could be that for some reason I do not understand, the whole thing runs in a chroot or some such. Ciao, Dscho ```