diff --git a/changelog/20752.txt b/changelog/20752.txt new file mode 100644 index 000000000000..667bc37f37b3 --- /dev/null +++ b/changelog/20752.txt @@ -0,0 +1,3 @@ +```release-note:feature +**Vault PKI ACME Server**: Support for the ACME certificate lifecycle management protocol has been added to the Vault PKI Plugin. This allows standard ACME clients, such as the EFF's certbot and the CNCF's k8s cert-manager, to request certificates from a Vault server with no knowledge of Vault APIs or authentication mechanisms. For public-facing Vault instances, we recommend requiring External Account Bindings (EAB) to limit the ability to request certificates to only authenticated clients. +``` diff --git a/website/content/api-docs/secret/pki.mdx b/website/content/api-docs/secret/pki.mdx index 9c2a4ecd35f9..7fddd167d108 100644 --- a/website/content/api-docs/secret/pki.mdx +++ b/website/content/api-docs/secret/pki.mdx @@ -19,6 +19,13 @@ update your API calls accordingly. ## Table of Contents - [Notice About New Multi-Issuer Functionality](#notice-about-new-multi-issuer-functionality) +- [ACME Certificate Issuance](#acme-certificate-issuance) + - [ACME Directories](#acme-directories) + - [Get ACME EAB Binding Token](#get-acme-eab-binding-token) + - [List Unused ACME EAB Binding Tokens](#list-unused-acme-eab-binding-tokens) + - [Delete Unused ACME EAB Binding Tokens](#delete-unused-acme-eab-binding-tokens) + - [Get ACME Configuration](#get-acme-configuration) + - [Set ACME Configuration](#set-acme-configuration) - [Issuing Certificates](#issuing-certificates) - [List Roles](#list-roles) - [Read Role](#read-role) @@ -106,6 +113,324 @@ to mix different types of CAs (roots and intermediates). current issuing certificate on migration from an older Vault version (Vault < 1.11.0). +## ACME Certificate Issuance + +Starting with Vault 1.14, Vault supports the [ACME certificate lifecycle +management protocol](https://datatracker.ietf.org/doc/html/rfc8555) for issuing +and renewing leaf server certificates. + +In order to use ACME, a [cluster path](#set-cluster-configuration) must be +set and ACME must be [enabled in its configuration](#set-acme-configuration) +with the [required headers](#acme-required-headers) enabled on the mount +tuning. + +Using ACME with a role requires `no_store=false` to be set on the role; this +allows the certificate to be stored and later fetched through the ACME +protocol. + +### ACME Directories + +Vault PKI supports the following ACME directories, providing different +restrictions around usage (defaults, a specific issuer and/or a specific +role). To interact with these directories, specify the directory URL in +an ACME client. For example, with the EFF's [CertBot](https://certbot.eff.org/): + +``` +$ certbot certonly --server https://localhost:8200/v1/pki/acme/directory ... +``` + +These endpoints are unauthenticated from a Vault authentication model, but +internally authenticated via the ACME protocol. + +| Method | Path | Issuer | Role | +| :----- | :--------------------------------------------------- | :-------------------- | :----------------------------------- | +| `ACME` | `/pki/acme/directory` | `default` | Sign-Verbatim or Specified in Config | +| `ACME` | `/pki/issuer/:issuer_ref/acme/directory` | `:issuer_ref` | Sign-Verbatim or Specified in Config | +| `ACME` | `/pki/roles/:role/acme/directory` | Specified by the role | `:role` | +| `ACME` | `/pki/issuer/:issuer_ref/roles/:role/acme/directory` | `:issuer_ref` | `:role` | + +When a role is not specified (for the first two directory URLs), and no +`default_role` is specified in the [ACME configuration](#set-acme-configuration), +then _any_ identifier for which the client can prove ownership of will be +issued for. This is similar to using the [Sign Verbatim](#sign-verbatim) +endpoint, but with additional verification that the client has proven +ownership (within the ACME protocol) of the requested certificate +identifiers. + +#### ACME Challenge Types + +Vault supports the following ACME challenge types presently: + + - `http-01`, supporting both `dns` and `ip` identifiers, + - `dns-01`, supporting `dns` identifiers including wildcards. + +A custom DNS resolver used by the server for looking up DNS names for use +with both mechanisms can be added via the [ACME configuration](#set-acme-configuration). + +#### ACME External Account Bindings + +ACME External Account Binding (EAB) Policy can enforce that clients need to +have a valid external account binding to Vault. Before registering a new account, +an authenticated Vault client will need to [fetch a new EAB +token](#get-acme-eab-binding-token). This returns two values: a key identifier +and an HMAC key used by the ACME client to authenticate with EAB. For example: + +``` +$ vault write -f /pki/acme/new-eab +$ certbot certonly --server https://localhost:8200/v1/pki/acme/directory \ + --eab-kid --eab-hmac-key +``` + +With or without EAB, requests from the ACME client are not authenticated using +traditional Vault authentication, but are instead authenticated through the +ACME protocol. With EAB however, a Vault authenticated client will have to +fetch an EAB token and pass it to the ACME client for use on the initial +registration: this binds the ACME client's registration to an authenticated +Vault endpoint, but not further to the client's entity or other information. + +~> Note: Enabling EAB is strongly recommended for public-facing Vault + deployments. Use of the `VAULT_DISABLE_PUBLIC_ACME` environment variable + can be used to enforce all ACME instances have EAB enabled. + +#### ACME Accounts + +ACME Accounts are created specific to a particular directory and are not +portable across Performance Secondary clusters. + +#### ACME Required Headers + +ACME requires the following response headers (`allowed_response_headers`) +to be specified by [mount tuning](/vault/api-docs/system/mounts#tune-mount-configuration): + + - `Replay-Nonce` + - `Link` + - `Location` + +On an existing mount, these can be specified by running the following command: + +``` +$ vault secrets tune -allowed-response-headers=Location -allowed-response-headers=Replay-Nonce \ + -allowed-response-headers=Link \ + pki/ +``` + +### Get ACME EAB Binding Token + +This endpoint returns a new ACME binding token. The `id` response field can +be used as the key identifier and the `key` response field be used as the +EAB HMAC key in the ACME Client. + +Each call to this endpoint will generate and return a new EAB binding token. + +| Method | Path | +| :----- | :------------------ | +| `POST` | `/pki/acme/new-eab` | + +#### Parameters + +No parameters. + +#### Sample Request + +``` +$ curl \ + --header "X-Vault-Token: ..." \ + --request POST \ + http://127.0.0.1:8200/v1/pki/acme/new-eab +``` + +#### Sample Response + +``` +{ + "data": { + "created_on": "2023-05-24T14:33:00-04:00", + "id": "bc8088d9-3816-5177-ae8e-d8393265f7dd", + "key_bits": "256", + "key_type": "hs", + "key": "MHcCAQE... additional data elided ...", + } +} +``` + +### List Unused ACME EAB Binding Tokens + +This endpoint returns a list of all unused ACME binding tokens; once used, +they will be removed from this list. + +| Method | Path | +| :----- | :--------- | +| `LIST` | `/pki/eab` | + +#### Sample Request + +``` +$ curl \ + --header "X-Vault-Token: ..." \ + --request LIST \ + http://127.0.0.1:8200/v1/pki/eab +``` + +#### Sample Response + +``` +{ + "data": { + "key_info": { + "bc8088d9-3816-5177-ae8e-d8393265f7dd": { + "created_on": "2023-05-24T14:33:00-04:00", + "key_bits": "256", + "key_type": "hs" + } + }, + "keys": [ + "bc8088d9-3816-5177-ae8e-d8393265f7dd" + ] + } +} +``` + +### Delete Unused ACME EAB Binding Tokens + +This endpoint allows the deletion of an unused ACME binding token. + +| Method | Path | +| :------- | :----------------- | +| `DELETE` | `/pki/eab/:key_id` | + +#### Parameters + + - `key_id` `(string: )` - The id of the EAB binding token to + delete. This is part of the request URL. + +#### Sample Request + +``` +$ curl \ + --header "X-Vault-Token: ..." \ + --request DELETE \ + http://127.0.0.1:8200/v1/pki/eab/bc8088d9-3816-5177-ae8e-d8393265f7dd +``` + +### Get ACME Configuration + +This endpoint allows reading of the current ACME server configuration used by +this mount. + +| Method | Path | +| :----- | :----------------- | +| `GET` | `/pki/config/acme` | + +#### Sample Request + +``` +$ curl \ + --header "X-Vault-Token: ..." \ + http://127.0.0.1:8200/v1/pki/config/acme +``` + +#### Sample Response + +``` +{ + "data": { + "allowed_issuers": [ + "*" + ], + "allowed_roles": [ + "*" + ], + "default_role": "", + "dns_resolver": "", + "eab_policy": "not-required", + "enabled": true + }, +} +``` + +### Set ACME Configuration + +This endpoint allows setting the ACME server configuration used by this +mount. + +| Method | Path | +| :----- | :----------------- | +| `POST` | `/pki/config/acme` | + +#### Parameters + + - `allowed_issuers` `(list: ["*"])` - Specifies a list issuers allowed to + issue certificates via explicit ACME paths. If an allowed role specifies + an issuer outside this list, it will be allowed. The default value `*` + allows every issuer within the mount. + + - `allowed_roles` `(list: ["*"])` - Specifies a list of roles to allow to + issue certificates via explicit ACME paths. If no `default_role` is + specified, sign-verbatim-like issuance on the default ACME directory + will still occur. + + - `default_role` `(string: "")` - Optionally specifies a role to enforce + on the default ACME directory. Must be present in `allowed_roles` if + set. + + - `dns_resolver` `(string: "")` - An optional overriding DNS resolver to + use for challenge verification lookups. When not specified, the default + system resolver will be used. This allows domains on peered networks with + an accessible DNS resolver to be validated. + + - `eab_policy` `(string: "not-required")` - Specified policy to enforce + around [External Account Bindings (EABs)](#acme-external-account-bindings). + The allowed values are: + + - `not-required`, where EABs are not enforced but are validated if + specified. + + - `new-account-required`, where new accounts are required to have EAB + but existing accounts can still be used. + + - `always-required`, where all accounts regardless of age are required + to have EABs set. + + - `enabled` `(bool: false)` - Whether ACME is enabled on this mount. When + ACME is disabled, all requests to ACME directory URLs will return 404. + +#### Sample Payload + +``` +{ + "enabled": true +} +``` + +#### Sample Request + +``` +$ curl \ + --header "X-Vault-Token: ..." \ + --request POST \ + --data @payload.json \ + http://127.0.0.1:8200/v1/pki/config/acme +``` + +#### Sample Response + +``` +{ + "data": { + "allowed_issuers": [ + "*" + ], + "allowed_roles": [ + "*" + ], + "default_role": "", + "dns_resolver": "", + "eab_policy": "not-required", + "enabled": true + } +} +``` + ## Issuing Certificates The following API endpoints allow users or operators to request certificates @@ -3867,6 +4192,23 @@ expiration time. still be there, but not too long as to fill up storage with too many invalid requests. Defaults to `48h`. + - `tidy_acme` `(bool: false)` - Set to true to tidy stale ACME accounts, + orders, authorizations, EABs, and challenges. ACME orders are tidied (deleted) + `safety_buffer` after the certificate associated with them expires, or after + the order and relevant authorizations have expired if no certificate was + produced. Authorizations are tidied with the corresponding order. + + When a valid ACME Account is at least `acme_account_safety_buffer` + old, and has no remaining orders associated with it, the account is + marked as revoked. After another `acme_account_safety_buffer` has + passed from the revocation or deactivation date, a revoked or + deactivated ACME account is deleted. + + - `acme_account_safety_buffer` `(string: "720h")` - The amount of time that + must pass after creation that an account with no orders is marked revoked, + and the amount of time after being marked revoked or deactivated. The + default is 30 days as hours. + #### Sample Payload ```json