c5665920f6
This removes all references I could find to: - credential provider - authentication backend - authentication provider - auth provider - auth backend in favor of the unified: - auth method
125 lines
4.4 KiB
Markdown
125 lines
4.4 KiB
Markdown
---
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layout: "docs"
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page_title: "TLS Certificates - Auth Methods"
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sidebar_current: "docs-auth-cert"
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description: |-
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The "cert" auth method allows users to authenticate with Vault using TLS client certificates.
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---
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# TLS Certificates Auth Method
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The `cert` auth method allows authentication using SSL/TLS client certificates
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which are either signed by a CA or self-signed.
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The trusted certificates and CAs are configured directly to the auth method
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using the `certs/` path. This method cannot read trusted certificates from an
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external source.
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CA certs are associated with a role; role names and CRL names are normalized to
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lower-case.
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## Revocation Checking
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Since Vault 0.4, the method supports revocation checking.
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An authorised user can submit PEM-formatted CRLs identified by a given name;
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these can be updated or deleted at will. (Note: Vault **does not** fetch CRLs;
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the CRLs themselves and any updates must be pushed into Vault when desired,
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such as via a `cron` job that fetches them from the source and pushes them into
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Vault.)
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When there are CRLs present, at the time of client authentication:
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* If the client presents any chain where no certificate in the chain matches a
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revoked serial number, authentication is allowed
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* If there is no chain presented by the client without a revoked serial number,
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authentication is denied
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This method provides good security while also allowing for flexibility. For
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instance, if an intermediate CA is going to be retired, a client can be
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configured with two certificate chains: one that contains the initial
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intermediate CA in the path, and the other that contains the replacement. When
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the initial intermediate CA is revoked, the chain containing the replacement
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will still allow the client to successfully authenticate.
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**N.B.**: Matching is performed by *serial number only*. For most CAs,
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including Vault's `pki` method, multiple CRLs can successfully be used as
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serial numbers are globally unique. However, since RFCs only specify that
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serial numbers must be unique per-CA, some CAs issue serial numbers in-order,
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which may cause clashes if attempting to use CRLs from two such CAs in the same
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mount of the method. The workaround here is to mount multiple copies of the
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`cert` method, configure each with one CA/CRL, and have clients connect to the
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appropriate mount.
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In addition, since the method does not fetch the CRLs itself, the CRL's
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designated time to next update is not considered. If a CRL is no longer in use,
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it is up to the administrator to remove it from the method.
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## Authentication
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### Via the CLI
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The below requires Vault to present a certificate signed by `ca.pem` and
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presents `cert.pem` (using `key.pem`) to authenticate against the `web` cert
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role. If a certificate role name is not specified, the auth method will try to
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authenticate against all trusted certificates.
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```
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$ vault login \
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-method=cert \
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-ca-cert=ca.pem \
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-client-cert=cert.pem \
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-client-key=key.pem \
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name=web
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```
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### Via the API
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The endpoint for the login is `/login`. The client simply connects with their
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TLS certificate and when the login endpoint is hit, the auth method will
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determine if there is a matching trusted certificate to authenticate the client.
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Optionally, you may specify a single certificate role to authenticate against.
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```sh
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$ curl \
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--request POST \
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--cacert ca.pem \
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--cert cert.pem \
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--key key.pem \
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--data '{"name": "web"}' \
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https://vault.rocks/v1/auth/cert/login
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```
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## Configuration
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Auth methods must be configured in advance before users or machines can
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authenticate. These steps are usually completed by an operator or configuration
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management tool.
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1. Enable the certificate auth method:
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```text
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$ vault auth enable cert
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```
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1. Configure it with trusted certificates that are allowed to authenticate:
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```text
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$ vault write auth/cert/certs/web \
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display_name=web \
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policies=web,prod \
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certificate=@web-cert.pem \
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ttl=3600
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```
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This creates a new trusted certificate "web" with same display name and the
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"web" and "prod" policies. The certificate (public key) used to verify
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clients is given by the "web-cert.pem" file. Lastly, an optional `ttl` value
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can be provided in seconds to limit the lease duration.
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## API
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The TLS Certificate auth method has a full HTTP API. Please see the
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[TLS Certificate API](/api/auth/cert/index.html) for more details.
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