When we are trying to fill a credential, we loop over the
set of defined credential-helpers, then fall back to running
askpass, and then finally prompt on the terminal. Helpers
which cannot find a credential are free to tell us nothing,
but they cannot currently ask us to stop prompting.
This patch lets them provide a "quit" attribute, which asks
us to stop the process entirely (avoiding running more
helpers, as well as the askpass/terminal prompt).
This has a few possible uses:
1. A helper which prompts the user itself (e.g., in a
dialog) can provide a "cancel" button to the user to
stop further prompts.
2. Some helpers may know that prompting cannot possibly
work. For example, if their role is to broker a ticket
from an external auth system and that auth system
cannot be contacted, there is no point in continuing
(we need a ticket to authenticate, and the user cannot
provide one by typing it in).
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Instead of outputing only the username and password, print all the
attributes, even those that already appeared in the input.
This is closer to what the C API does, and allows one to take the exact
output of "git credential fill" as input to "git credential approve" or
"git credential reject".
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When parsing a URL into a credential struct, we carefully
record each part of the URL, including the path on the
remote host, and use the result as part of the credential
context.
This had two practical implications:
1. Credential helpers which store a credential for later
access are likely to use the "path" portion as part of
the storage key. That means that a request to
https://example.com/foo.git
would not use the same credential that was stored in an
earlier request for:
https://example.com/bar.git
2. The prompt shown to the user includes all relevant
context, including the path.
In most cases, however, users will have a single password
per host. The behavior in (1) will be inconvenient, and the
prompt in (2) will be overly long.
This patch introduces a config option to toggle the
relevance of http paths. When turned on, we use the path as
before. When turned off, we drop the path component from the
context: helpers don't see it, and it does not appear in the
prompt.
This is nothing you couldn't do with a clever credential
helper at the start of your stack, like:
[credential "http://"]
helper = "!f() { grep -v ^path= ; }; f"
helper = your_real_helper
But doing this:
[credential]
useHttpPath = false
is way easier and more readable. Furthermore, since most
users will want the "off" behavior, that is the new default.
Users who want it "on" can set the variable (either for all
credentials, or just for a subset using
credential.*.useHttpPath).
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The functionality for credential storage helpers is already
there; we just need to give the users a way to turn it on.
This patch provides a "credential.helper" configuration
variable which allows the user to provide one or more helper
strings.
Rather than simply matching credential.helper, we will also
compare URLs in subsection headings to the current context.
This means you can apply configuration to a subset of
credentials. For example:
[credential "https://example.com"]
helper = foo
would match a request for "https://example.com/foo.git", but
not one for "https://kernel.org/foo.git".
This is overkill for the "helper" variable, since users are
unlikely to want different helpers for different sites (and
since helpers run arbitrary code, they could do the matching
themselves anyway).
However, future patches will add new config variables where
this extra feature will be more useful.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
All of the components of a credential struct can be found in
a URL. For example, the URL:
http://foo:bar@example.com/repo.git
contains:
protocol=http
host=example.com
path=repo.git
username=foo
password=bar
We want to be able to turn URLs into broken-down credential
structs so that we know two things:
1. Which parts of the username/password we still need
2. What the context of the request is (for prompting or
as a key for storing credentials).
This code is based on http_auth_init in http.c, but needed a
few modifications in order to get all of the components that
the credential object is interested in.
Once the http code is switched over to the credential API,
then http_auth_init can just go away.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
There are a few places in git that need to get a username
and password credential from the user; the most notable one
is HTTP authentication for smart-http pushing.
Right now the only choices for providing credentials are to
put them plaintext into your ~/.netrc, or to have git prompt
you (either on the terminal or via an askpass program). The
former is not very secure, and the latter is not very
convenient.
Unfortunately, there is no "always best" solution for
password management. The details will depend on the tradeoff
you want between security and convenience, as well as how
git can integrate with other security systems (e.g., many
operating systems provide a keychain or password wallet for
single sign-on).
This patch provides an abstract notion of credentials as a
data item, and provides three basic operations:
- fill (i.e., acquire from external storage or from the
user)
- approve (mark a credential as "working" for further
storage)
- reject (mark a credential as "not working", so it can
be removed from storage)
These operations can be backed by external helper processes
that interact with system- or user-specific secure storage.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
