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 2.48.0 2025-01-10 git-credential(1)
git 2.48.0 - Generated Sat Jan 11 09:20:00 CST 2025