The steps advised, in documentation, for setting up access to repositories via SSH seems to not be working for CentOS 7.
According to the steps in the guide, vcs-user should be used in both sshd_config and the ssh-hook script.
On CentOS 7 this appears to cause Permission denied errors (status code 126).
Working solution, so far, is to set AuthorizedKeysCommandUser to the daemon-user.
I have taken the following, other, steps in an attempt to fix it:
Adding the daemon-user group to the groups vcs-user are in
Using sudo/su to change to the daemon-user in the SSH-hook script
In sudoers, giving the vcs-user access to the ssh-auth and ssh-exec scripts
Environment (the ones i could think of that could matter, maybe):
CentOS Linux release 7.0.1406 (Core)
nginx/1.7.9
PHP 5.4.16 (fpm-fcgi)
5.5.40-MariaDB
OpenSSH_6.4p1
OpenSSL 1.0.1e-fips