GIT-CREDENTIAL(1) Git Manual GIT-CREDENTIAL(1)

NAME

git-credential - Retrieve and store user credentials

SYNOPSIS

'git credential' (fill|approve|reject|capability)

DESCRIPTION

Git has an internal interface for storing and retrieving credentials
from system-specific helpers, as well as prompting the user for
usernames and passwords. The git-credential command exposes this
interface to scripts which may want to retrieve, store, or prompt for
credentials in the same manner as Git. The design of this scriptable
interface models the internal C API; see credential.h for more
background on the concepts.

git-credential takes an "action" option on the command-line (one of
fill, approve, or reject) and reads a credential description on stdin
(see INPUT/OUTPUT FORMAT).

If the action is fill, git-credential will attempt to add "username"
and "password" attributes to the description by reading config files,
by contacting any configured credential helpers, or by prompting the
user. The username and password attributes of the credential
description are then printed to stdout together with the attributes
already provided.

If the action is approve, git-credential will send the description to
any configured credential helpers, which may store the credential for
later use.

If the action is reject, git-credential will send the description to
any configured credential helpers, which may erase any stored
credentials matching the description.

If the action is capability, git-credential will announce any
capabilities it supports to standard output.

If the action is approve or reject, no output should be emitted.

TYPICAL USE OF GIT CREDENTIAL

An application using git-credential will typically use git credential
following these steps:

1. Generate a credential description based on the context.

For example, if we want a password for
https://example.com/foo.git, we might generate the following
credential description (don't forget the blank line at the end;
it tells git credential that the application finished feeding all
the information it has):

protocol=https
host=example.com
path=foo.git

2. Ask git-credential to give us a username and password for this
description. This is done by running git credential fill, feeding
the description from step (1) to its standard input. The complete
credential description (including the credential per se, i.e. the
login and password) will be produced on standard output, like:

protocol=https
host=example.com
username=bob
password=secr3t

In most cases, this means the attributes given in the input will
be repeated in the output, but Git may also modify the credential
description, for example by removing the path attribute when the
protocol is HTTP(s) and credential.useHttpPath is false.

If the git credential knew about the password, this step may not
have involved the user actually typing this password (the user
may have typed a password to unlock the keychain instead, or no
user interaction was done if the keychain was already unlocked)
before it returned password=secr3t.

3. Use the credential (e.g., access the URL with the username and
password from step (2)), and see if it's accepted.

4. Report on the success or failure of the password. If the
credential allowed the operation to complete successfully, then
it can be marked with an "approve" action to tell git credential
to reuse it in its next invocation. If the credential was
rejected during the operation, use the "reject" action so that
git credential will ask for a new password in its next
invocation. In either case, git credential should be fed with the
credential description obtained from step (2) (which also
contains the fields provided in step (1)).

INPUT/OUTPUT FORMAT
git credential reads and/or writes (depending on the action used)
credential information in its standard input/output. This information
can correspond either to keys for which git credential will obtain
the login information (e.g. host, protocol, path), or to the actual
credential data to be obtained (username/password).

The credential is split into a set of named attributes, with one
attribute per line. Each attribute is specified by a key-value pair,
separated by an = (equals) sign, followed by a newline.

The key may contain any bytes except =, newline, or NUL. The value
may contain any bytes except newline or NUL. A line, including the
trailing newline, may not exceed 65535 bytes in order to allow
implementations to parse efficiently.

Attributes with keys that end with C-style array brackets [] can have
multiple values. Each instance of a multi-valued attribute forms an
ordered list of values - the order of the repeated attributes defines
the order of the values. An empty multi-valued attribute (key[]=\n)
acts to clear any previous entries and reset the list.

In all cases, all bytes are treated as-is (i.e., there is no quoting,
and one cannot transmit a value with newline or NUL in it). The list
of attributes is terminated by a blank line or end-of-file.

Git understands the following attributes:

protocol
The protocol over which the credential will be used (e.g.,
https).

host
The remote hostname for a network credential. This includes the
port number if one was specified (e.g., "example.com:8088").

path
The path with which the credential will be used. E.g., for
accessing a remote https repository, this will be the
repository's path on the server.

username
The credential's username, if we already have one (e.g., from a
URL, the configuration, the user, or from a previously run
helper).

password
The credential's password, if we are asking it to be stored.

password_expiry_utc
Generated passwords such as an OAuth access token may have an
expiry date. When reading credentials from helpers, git
credential fill ignores expired passwords. Represented as Unix
time UTC, seconds since 1970.

oauth_refresh_token
An OAuth refresh token may accompany a password that is an OAuth
access token. Helpers must treat this attribute as confidential
like the password attribute. Git itself has no special behaviour
for this attribute.

url
When this special attribute is read by git credential, the value
is parsed as a URL and treated as if its constituent parts were
read (e.g., url=https://example.com would behave as if
protocol=https and host=example.com had been provided). This can
help callers avoid parsing URLs themselves.

Note that specifying a protocol is mandatory and if the URL
doesn't specify a hostname (e.g., "cert:///path/to/file") the
credential will contain a hostname attribute whose value is an
empty string.

Components which are missing from the URL (e.g., there is no
username in the example above) will be left unset.

authtype
This indicates that the authentication scheme in question should
be used. Common values for HTTP and HTTPS include basic, bearer,
and digest, although the latter is insecure and should not be
used. If credential is used, this may be set to an arbitrary
string suitable for the protocol in question (usually HTTP).

This value should not be sent unless the appropriate capability
(see below) is provided on input.

credential
The pre-encoded credential, suitable for the protocol in question
(usually HTTP). If this key is sent, authtype is mandatory, and
username and password are not used. For HTTP, Git concatenates
the authtype value and this value with a single space to
determine the Authorization header.

This value should not be sent unless the appropriate capability
(see below) is provided on input.

ephemeral
This boolean value indicates, if true, that the value in the
credential field should not be saved by the credential helper
because its usefulness is limited in time. For example, an HTTP
Digest credential value is computed using a nonce and reusing it
will not result in successful authentication. This may also be
used for situations with short duration (e.g., 24-hour)
credentials. The default value is false.

The credential helper will still be invoked with store or erase
so that it can determine whether the operation was successful.

This value should not be sent unless the appropriate capability
(see below) is provided on input.

state[]
This value provides an opaque state that will be passed back to
this helper if it is called again. Each different credential
helper may specify this once. The value should include a prefix
unique to the credential helper and should ignore values that
don't match its prefix.

This value should not be sent unless the appropriate capability
(see below) is provided on input.

continue
This is a boolean value, which, if enabled, indicates that this
authentication is a non-final part of a multistage authentication
step. This is common in protocols such as NTLM and Kerberos,
where two rounds of client authentication are required, and
setting this flag allows the credential helper to implement the
multistage authentication step. This flag should only be sent if
a further stage is required; that is, if another round of
authentication is expected.

This value should not be sent unless the appropriate capability
(see below) is provided on input. This attribute is one-way from
a credential helper to pass information to Git (or other programs
invoking git credential).

wwwauth[]
When an HTTP response is received by Git that includes one or
more WWW-Authenticate authentication headers, these will be
passed by Git to credential helpers.

Each WWW-Authenticate header value is passed as a multi-valued
attribute wwwauth[], where the order of the attributes is the
same as they appear in the HTTP response. This attribute is
one-way from Git to pass additional information to credential
helpers.

capability[]
This signals that Git, or the helper, as appropriate, supports
the capability in question. This can be used to provide better,
more specific data as part of the protocol. A capability[]
directive must precede any value depending on it and these
directives should be the first item announced in the protocol.

There are two currently supported capabilities. The first is
authtype, which indicates that the authtype, credential, and
ephemeral values are understood. The second is state, which
indicates that the state[] and continue values are understood.

It is not obligatory to use the additional features just because
the capability is supported, but they should not be provided
without the capability.

Unrecognised attributes and capabilities are silently discarded.

CAPABILITY INPUT/OUTPUT FORMAT
For git credential capability, the format is slightly different.
First, a version 0 announcement is made to indicate the current
version of the protocol, and then each capability is announced with a
line like capability authtype. Credential helpers may also implement
this format, again with the capability argument. Additional lines may
be added in the future; callers should ignore lines which they don't
understand.

Because this is a new part of the credential helper protocol, older
versions of Git, as well as some credential helpers, may not support
it. If a non-zero exit status is received, or if the first line
doesn't start with the word version and a space, callers should
assume that no capabilities are supported.

The intention of this format is to differentiate it from the
credential output in an unambiguous way. It is possible to use very
simple credential helpers (e.g., inline shell scripts) which always
produce identical output. Using a distinct format allows users to
continue to use this syntax without having to worry about correctly
implementing capability advertisements or accidentally confusing
callers querying for capabilities.

GIT

Part of the git(1) suite

Git 2.48.1 2025-01-13 GIT-CREDENTIAL(1)