# community.crypto.openssl_dhparam module – Generate OpenSSL Diffie-Hellman Parameters

Note

This module is part of the community.crypto collection (version 2.10.0).

To install it, use: `ansible-galaxy collection install community.crypto`. You need further requirements to be able to use this module, see Requirements for details.

To use it in a playbook, specify: `community.crypto.openssl_dhparam`.

- Synopsis

- Requirements

- Parameters

- Attributes

- See Also

- Examples

- Return Values

## Synopsis

- This module allows one to (re)generate OpenSSL DH-params.

- This module uses file common arguments to specify generated file permissions.

- Please note that the module regenerates existing DH params if they do not match the module’s options. If you are concerned that this could overwrite your existing DH params, consider using the backup option.

- The module can use the cryptography Python library, or the `openssl` executable. By default, it tries to detect which one is available. This can be overridden with the select_crypto_backend option.

## Requirements

The below requirements are needed on the host that executes this module.

- Either cryptography >= 2.0

- Or OpenSSL binary `openssl`

## Parameters

Parameter | Comments
--- | ---
attributes aliases: attr string | The attributes the resulting filesystem object should have. To get supported flags look at the man page for chattr on the target system. This string should contain the attributes in the same order as the one displayed by lsattr. The `=` operator is assumed as default, otherwise `+` or `-` operators need to be included in the string.

backup

boolean

Create a backup file including a timestamp so you can get the original DH params back if you overwrote them with new ones by accident.

Choices:

- `false` ← (default)

- `true`

force

boolean

Should the parameters be regenerated even it it already exists.

Choices:

- `false` ← (default)

- `true`

group string | Name of the group that should own the filesystem object, as would be fed to chown. When left unspecified, it uses the current group of the current user unless you are root, in which case it can preserve the previous ownership.

mode

any

The permissions the resulting filesystem object should have.

For those used to /usr/bin/chmod remember that modes are actually octal numbers. You must either add a leading zero so that Ansible’s YAML parser knows it is an octal number (like `0644` or `01777`) or quote it (like `'644'` or `'1777'`) so Ansible receives a string and can do its own conversion from string into number.

Giving Ansible a number without following one of these rules will end up with a decimal number which will have unexpected results.

As of Ansible 1.8, the mode may be specified as a symbolic mode (for example, `u+rwx` or `u=rw,g=r,o=r`).

If `mode` is not specified and the destination filesystem object does not exist, the default `umask` on the system will be used when setting the mode for the newly created filesystem object.

If `mode` is not specified and the destination filesystem object does exist, the mode of the existing filesystem object will be used.

Specifying `mode` is the best way to ensure filesystem objects are created with the correct permissions. See CVE-2020-1736 for further details.

owner string | Name of the user that should own the filesystem object, as would be fed to chown. When left unspecified, it uses the current user unless you are root, in which case it can preserve the previous ownership.
path path / required | Name of the file in which the generated parameters will be saved.

return_content

boolean

added in community.crypto 1.0.0

If set to `true`, will return the (current or generated) DH parameter’s content as dhparams.

Choices:

- `false` ← (default)

- `true`

select_crypto_backend

string

added in community.crypto 1.0.0

Determines which crypto backend to use.

The default choice is `auto`, which tries to use `cryptography` if available, and falls back to `openssl`.

If set to `openssl`, will try to use the OpenSSL `openssl` executable.

If set to `cryptography`, will try to use the cryptography library.

Choices:

- `"auto"` ← (default)

- `"cryptography"`

- `"openssl"`

selevel string | The level part of the SELinux filesystem object context. This is the MLS/MCS attribute, sometimes known as the `range`. When set to `_default`, it will use the `level` portion of the policy if available.
serole string | The role part of the SELinux filesystem object context. When set to `_default`, it will use the `role` portion of the policy if available.
setype string | The type part of the SELinux filesystem object context. When set to `_default`, it will use the `type` portion of the policy if available.
seuser string | The user part of the SELinux filesystem object context. By default it uses the `system` policy, where applicable. When set to `_default`, it will use the `user` portion of the policy if available.
size integer | Size (in bits) of the generated DH-params. Default: `4096`

state

string

Whether the parameters should exist or not, taking action if the state is different from what is stated.

Choices:

- `"absent"`

- `"present"` ← (default)

unsafe_writes

boolean

Influence when to use atomic operation to prevent data corruption or inconsistent reads from the target filesystem object.

By default this module uses atomic operations to prevent data corruption or inconsistent reads from the target filesystem objects, but sometimes systems are configured or just broken in ways that prevent this. One example is docker mounted filesystem objects, which cannot be updated atomically from inside the container and can only be written in an unsafe manner.

This option allows Ansible to fall back to unsafe methods of updating filesystem objects when atomic operations fail (however, it doesn’t force Ansible to perform unsafe writes).

IMPORTANT! Unsafe writes are subject to race conditions and can lead to data corruption.

Choices:

- `false` ← (default)

- `true`

## Attributes

Attribute | Support | Description
--- | --- | ---
check_mode | Support: full | Can run in `check_mode` and return changed status prediction without modifying target.
diff_mode | Support: none | Will return details on what has changed (or possibly needs changing in `check_mode`), when in diff mode.
safe_file_operations | Support: full | Uses Ansible’s strict file operation functions to ensure proper permissions and avoid data corruption.

## See Also

See also

community.crypto.x509_certificate

  Generate and/or check OpenSSL certificates.

community.crypto.openssl_csr

  Generate OpenSSL Certificate Signing Request (CSR).

community.crypto.openssl_pkcs12

  Generate OpenSSL PKCS#12 archive.

community.crypto.openssl_privatekey

  Generate OpenSSL private keys.

community.crypto.openssl_publickey

  Generate an OpenSSL public key from its private key.

## Examples

    - name: Generate Diffie-Hellman parameters with the default size (4096 bits)
      community.crypto.openssl_dhparam:
        path: /etc/ssl/dhparams.pem

    - name: Generate DH Parameters with a different size (2048 bits)
      community.crypto.openssl_dhparam:
        path: /etc/ssl/dhparams.pem
        size: 2048

    - name: Force regenerate an DH parameters if they already exist
      community.crypto.openssl_dhparam:
        path: /etc/ssl/dhparams.pem
        force: true

## Return Values

Common return values are documented here, the following are the fields unique to this module:

Key | Description
--- | ---
backup_file string | Name of backup file created. Returned: changed and if backup is `true` Sample: `"/path/to/dhparams.pem.2019-03-09@11:22~"`
dhparams string added in community.crypto 1.0.0 | The (current or generated) DH params’ content. Returned: if state is `present` and return_content is `true`
filename string | Path to the generated Diffie-Hellman parameters. Returned: changed or success Sample: `"/etc/ssl/dhparams.pem"`
size integer | Size (in bits) of the Diffie-Hellman parameters. Returned: changed or success Sample: `4096`

### Authors

- Thom Wiggers (@thomwiggers)

### Collection links

Issue Tracker Repository (Sources) Submit a bug report Request a feature Communication