[SOLVED] nginx with git-http-backend: insufficent access permission for `git push` with www-data user

nginx with git-http-backend: insufficent access permission for `git push` with www-data user

I am trying to set up nginx with fcgiwrap to forward requests under https://<host>/git/<repo>.git to git-http-backend.

The server is freshly installed debian linux, so there should be no awkward things in the background.

Error scenario

The fcgiwrap socket runs as www-data user and should have access to the git repository (see below). However, when trying to push I get below git message (pertaining to a problem with access permission, I presume):

$ git push origin master
Counting objects: 6, done.
Delta compression using up to 8 threads.
Compressing objects: 100% (2/2), done.
Writing objects: 100% (6/6), 385 bytes | 0 bytes/s, done.
Total 6 (delta 0), reused 0 (delta 0)
remote: error: insufficient permission for adding an object to repository database objects
remote: fatal: failed to write object
error: unpack failed: unpack-objects abnormal exit
To https://xxx:xxx@127.0.0.1/git/test.git
 ! [remote rejected] master -> master (unpacker error)
error: failed to push some refs to 'https://xxx:xxx@127.0.0.1/git/test.git'

Setup

nginx config:

server {                                                                                                                                                                          
        server_name  xxxxxxx.com;                                                                                                                                        

        location ~ /git(/.*) {                                                                                                                                                    
                auth_basic      "Private Git Repository";                                                                                                                         
                auth_basic_user_file /etc/nginx/.htpasswd;                                                                                                                        

                # fcgiwrap is set up to listen on this host:port                                                                                                                  
                fastcgi_pass unix:/var/run/fcgiwrap.socket;                                                                                                                       
                include       fastcgi_params;
                fastcgi_param SCRIPT_FILENAME     /usr/lib/git-core/git-http-backend;
                # export all repositories under GIT_PROJECT_ROOT
                fastcgi_param GIT_HTTP_EXPORT_ALL "";
                fastcgi_param GIT_PROJECT_ROOT    /opt/git;
                fastcgi_param PATH_INFO           $1;
                fastcgi_param REMOTE_USER $remote_user;
        }
}

FastCGIWrap:

$ apt-get install fcgiwrap
$ cat /etc/init.d/fcgiwrap
...
FCGI_USER="www-data"
FCGI_GROUP="www-data"
# Socket owner/group (will default to FCGI_USER/FCGI_GROUP if not defined)
FCGI_SOCKET_OWNER="www-data"
FCGI_SOCKET_GROUP="www-data"
...

Permissions in /opt/git:

$ chown -R git:git /opt/git/
$ chmod -R 775 /opt/git/
$ chmod -R a+s /opt/git/
$ ls -la /opt/git                                                                                                                         0 !193 0jobs
drwsrwsr-x 6 git  git  4096 Aug 11 15:21 .
drwxr-xr-x 3 root root 4096 Jul 15 12:01 ..
drwsrwsr-x 7 git  git  4096 Aug 12 11:47 test.git

git repo config:

$ cat /opt/git/test.git/config
[core]
        repositoryformatversion = 0
        filemode = true
        bare = true
        sharedrepository = 1
        sharedRepository = 1
[receive]
        denyNonFastforwards = true
[http]
    receivepack = true

nginx user is www-data which is a member of git group:

$ groups www-data
www-data : www-data git
$ cat /etc/group | grep www-data
www-data:x:33:
git:x:1001:www-data

Workarounds

Oddly, if I chgrp -R www-data /opt/git/ it works. I would like to have it as git:git though.
chmod a+s /usr/lib/git-core/git-http-* works. Now I can also do chmod -R 705 /opt/git/ and it works. I suppose because now the root user executes the commands. I doubt this is secure. So it should not be used...
Use ssh. Using ssh works, or even logging in as user www-data and pushing directly to the repo works (since the group permissions ARE set correctly!). However, this is no option as https access is required!

What am I missing?

I'm running out of ideas. Pushing per ssh works. If I do chown -R 770 /opt/git/ then I can't even clone or fetch via https any more. So it seems like www-data user does not have access via the git-http-backend cgi script. But why??? The user is a member of the git group and should have group access!!!

Related

Error pushing to GitHub - insufficient permission for adding an object to repository database : Focuses on permissions but does not mention an answer to the specific problem of an nginx user not having access via git-http-backend.

Solution

Reboot !!

Can't believe it... A simple server reboot solved it.

I just came to trying this because I had to actually log out and back in when adding group permission to my user. Seems like permission stuff sometimes does not apply on-the-fly? Wow...