In some applications of the update hook a user may be allowed to
modify a branch, but only if the file level difference is also an
allowed change. This is the commonly requested feature of allowing
users to modify only certain files.
A new repository.*.allow syntax permits granting the three basic
file level operations:
A: file is added relative to the other tree
M: file exists in both trees, but its SHA-1 or mode differs
D: file is removed relative to the other tree
on a per-branch and path-name basis. The user must also have a
branch level allow line already granting them access to create,
rewind or update (CRU) that branch before the hook will consult
any file level rules.
In order for a branch change to succeed _all_ files that differ
relative to some base (by default the old value of this branch,
but it can also be any valid tree-ish) must be allowed by file
level allow rules. A push is rejected if any diff exists that
is not covered by at least one allow rule.
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In some applications of this paranoid update hook the set of ACL
rules that need to be applied to a user can be large, and the
number of users that those rules must also be applied to can be
more than a handful of individuals. Rather than repeating the same
rules multiple times (once for each user) we now allow users to be
members of groups, where the group supplies the list of ACL rules.
For various reasons we don't depend on the underlying OS groups
and instead perform our own group handling.
Users can be made a member of one or more groups by setting the
user.memberOf property within the "users/$who.acl" file:
[user]
memberOf = developer
memberOf = administrator
This will cause the hook to also parse the "groups/$groupname.acl"
file for each value of user.memberOf, and merge any allow rules
that match the current repository with the user's own private rules
(if they had any).
Since some rules are basically the same but may have a component
differ based on the individual user, any user.* key may be inserted
into a rule using the "${user.foo}" syntax. The allow rule does
not match if the user does not define one (and exactly one) value
for the key "foo".
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
I'm using a variant of this update hook in a corporate environment
where we perform some validations of the commits and tags that
are being pushed. The model is a "central repository" type setup,
where users are given access to push to specific branches within
the shared central repository. In this particular installation we
run a specially patched git-receive-pack in setuid mode via SSH,
allowing all writes into the repository as the repository owner,
but only if this hook blesses it.
One of the major checks we perform with this hook is that the
'committer' line of a commit, or the 'tagger' line of a new annotated
tag actually correlates to the UNIX user who is performing the push.
Users can falsify these lines on their local repositories, but
the central repository that management trusts will reject all such
forgery attempts. Of course 'author' lines are still allowed to
be any value, as sometimes changes do come from other individuals.
Another nice feature of this hook is the access control lists for
all repositories on the system can also be stored and tracked in
a supporting Git repository, which can also be access controlled
by itself. This allows full auditing of who-had-what-when-and-why,
thanks to git-blame's data mining capabilities.
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
