<?php
namespace Aws\Credentials;
use Aws;
use Aws\Api\DateTimeResult;
use Aws\CacheInterface;
use Aws\Exception\CredentialsException;
use Aws\Sts\StsClient;
use GuzzleHttp\Promise;
/**
* Credential providers are functions that accept no arguments and return a
* promise that is fulfilled with an {@see \Aws\Credentials\CredentialsInterface}
* or rejected with an {@see \Aws\Exception\CredentialsException}.
*
* <code>
* use Aws\Credentials\CredentialProvider;
* $provider = CredentialProvider::defaultProvider();
* // Returns a CredentialsInterface or throws.
* $creds = $provider()->wait();
* </code>
*
* Credential providers can be composed to create credentials using conditional
* logic that can create different credentials in different environments. You
* can compose multiple providers into a single provider using
* {@see Aws\Credentials\CredentialProvider::chain}. This function accepts
* providers as variadic arguments and returns a new function that will invoke
* each provider until a successful set of credentials is returned.
*
* <code>
* // First try an INI file at this location.
* $a = CredentialProvider::ini(null, '/path/to/file.ini');
* // Then try an INI file at this location.
* $b = CredentialProvider::ini(null, '/path/to/other-file.ini');
* // Then try loading from environment variables.
* $c = CredentialProvider::env();
* // Combine the three providers together.
* $composed = CredentialProvider::chain($a, $b, $c);
* // Returns a promise that is fulfilled with credentials or throws.
* $promise = $composed();
* // Wait on the credentials to resolve.
* $creds = $promise->wait();
* </code>
*/
class CredentialProvider
{
const ENV_ARN = 'AWS_ROLE_ARN';
const ENV_KEY = 'AWS_ACCESS_KEY_ID';
const ENV_PROFILE = 'AWS_PROFILE';
const ENV_ROLE_SESSION_NAME = 'AWS_ROLE_SESSION_NAME';
const ENV_SECRET = 'AWS_SECRET_ACCESS_KEY';
const ENV_SESSION = 'AWS_SESSION_TOKEN';
const ENV_TOKEN_FILE = 'AWS_WEB_IDENTITY_TOKEN_FILE';
const ENV_SHARED_CREDENTIALS_FILE = 'AWS_SHARED_CREDENTIALS_FILE';
/**
* Create a default credential provider that
* first checks for environment variables,
* then checks for assumed role via web identity,
* then checks for cached SSO credentials from the CLI,
* then check for credential_process in the "default" profile in ~/.aws/credentials,
* then checks for the "default" profile in ~/.aws/credentials,
* then for credential_process in the "default profile" profile in ~/.aws/config,
* then checks for "profile default" profile in ~/.aws/config (which is
* the default profile of AWS CLI),
* then tries to make a GET Request to fetch credentials if ECS environment variable is presented,
* finally checks for EC2 instance profile credentials.
*
* This provider is automatically wrapped in a memoize function that caches
* previously provided credentials.
*
* @param array $config Optional array of ecs/instance profile credentials
* provider options.
*
* @return callable
*/
public static function defaultProvider(array $config = [])
{
$cacheable = [
'web_identity',
'sso',
'process_credentials',
'process_config',
'ecs',
'instance'
];
$defaultChain = [
'env' => self::env(),
'web_identity' => self::assumeRoleWithWebIdentityCredentialProvider($config),
];
if (
!isset($config['use_aws_shared_config_files'])
|| $config['use_aws_shared_config_files'] !== false
) {
$defaultChain['sso'] = self::sso(
'profile default',
self::getHomeDir() . '/.aws/config',
$config
);
$defaultChain['process_credentials'] = self::process();
$defaultChain['ini'] = self::ini();
$defaultChain['process_config'] = self::process(
'profile default',
self::getHomeDir() . '/.aws/config'
);
$defaultChain['ini_config'] = self::ini(
'profile default',
self::getHomeDir() . '/.aws/config'
);
}
$shouldUseEcsCredentialsProvider = getenv(EcsCredentialProvider::ENV_URI);
// getenv() is not thread safe - fall back to $_SERVER
if ($shouldUseEcsCredentialsProvider === false) {
$shouldUseEcsCredentialsProvider = isset($_SERVER[EcsCredentialProvider::ENV_URI])
? $_SERVER[EcsCredentialProvider::ENV_URI]
: false;
}
if (!empty($shouldUseEcsCredentialsProvider)) {
$defaultChain['ecs'] = self::ecsCredentials($config);
} else {
$defaultChain['instance'] = self::instanceProfile($config);
}
if (isset($config['credentials'])
&& $config['credentials'] instanceof CacheInterface
) {
foreach ($cacheable as $provider) {
if (isset($defaultChain[$provider])) {
$defaultChain[$provider] = self::cache(
$defaultChain[$provider],
$config['credentials'],
'aws_cached_' . $provider . '_credentials'
);
}
}
}
return self::memoize(
call_user_func_array(
'self::chain',
array_values($defaultChain)
)
);
}
/**
* Create a credential provider function from a set of static credentials.
*
* @param CredentialsInterface $creds
*
* @return callable
*/
public static function fromCredentials(CredentialsInterface $creds)
{
$promise = Promise\promise_for($creds);
return function () use ($promise) {
return $promise;
};
}
/**
* Creates an aggregate credentials provider that invokes the provided
* variadic providers one after the other until a provider returns
* credentials.
*
* @return callable
*/
public static function chain()
{
$links = func_get_args();
if (empty($links)) {
throw new \InvalidArgumentException('No providers in chain');
}
return function () use ($links) {
/** @var callable $parent */
$parent = array_shift($links);
$promise = $parent();
while ($next = array_shift($links)) {
$promise = $promise->otherwise($next);
}
return $promise;
};
}
/**
* Wraps a credential provider and caches previously provided credentials.
*
* Ensures that cached credentials are refreshed when they expire.
*
* @param callable $provider Credentials provider function to wrap.
*
* @return callable
*/
public static function memoize(callable $provider)
{
return function () use ($provider) {
static $result;
static $isConstant;
// Constant credentials will be returned constantly.
if ($isConstant) {
return $result;
}
// Create the initial promise that will be used as the cached value
// until it expires.
if (null === $result) {
$result = $provider();
}
// Return credentials that could expire and refresh when needed.
return $result
->then(function (CredentialsInterface $creds) use ($provider, &$isConstant, &$result) {
// Determine if these are constant credentials.
if (!$creds->getExpiration()) {
$isConstant = true;
return $creds;
}
// Refresh expired credentials.
if (!$creds->isExpired()) {
return $creds;
}
// Refresh the result and forward the promise.
return $result = $provider();
})
->otherwise(function($reason) use (&$result) {
// Cleanup rejected promise.
$result = null;
return new Promise\RejectedPromise($reason);
});
};
}
/**
* Wraps a credential provider and saves provided credentials in an
* instance of Aws\CacheInterface. Forwards calls when no credentials found
* in cache and updates cache with the results.
*
* @param callable $provider Credentials provider function to wrap
* @param CacheInterface $cache Cache to store credentials
* @param string|null $cacheKey (optional) Cache key to use
*
* @return callable
*/
public static function cache(
callable $provider,
CacheInterface $cache,
$cacheKey = null
) {
$cacheKey = $cacheKey ?: 'aws_cached_credentials';
return function () use ($provider, $cache, $cacheKey) {
$found = $cache->get($cacheKey);
if ($found instanceof CredentialsInterface && !$found->isExpired()) {
return Promise\promise_for($found);
}
return $provider()
->then(function (CredentialsInterface $creds) use (
$cache,
$cacheKey
) {
$cache->set(
$cacheKey,
$creds,
null === $creds->getExpiration() ?
0 : $creds->getExpiration() - time()
);
return $creds;
});
};
}
/**
* Provider that creates credentials from environment variables
* AWS_ACCESS_KEY_ID, AWS_SECRET_ACCESS_KEY, and AWS_SESSION_TOKEN.
*
* @return callable
*/
public static function env()
{
return function () {
// Use credentials from environment variables, if available
$key = getenv(self::ENV_KEY);
$secret = getenv(self::ENV_SECRET);
if ($key && $secret) {
return Promise\promise_for(
new Credentials($key, $secret, getenv(self::ENV_SESSION) ?: NULL)
);
}
return self::reject('Could not find environment variable '
. 'credentials in ' . self::ENV_KEY . '/' . self::ENV_SECRET);
};
}
/**
* Credential provider that creates credentials using instance profile
* credentials.
*
* @param array $config Array of configuration data.
*
* @return InstanceProfileProvider
* @see Aws\Credentials\InstanceProfileProvider for $config details.
*/
public static function instanceProfile(array $config = [])
{
return new InstanceProfileProvider($config);
}
/**
* Credential provider that retrieves cached SSO credentials from the CLI
*
* @return callable
*/
public static function sso($ssoProfileName, $filename = null, $config = [])
{
$filename = $filename ?: (self::getHomeDir() . '/.aws/config');
return function () use ($ssoProfileName, $filename, $config) {
if (!is_readable($filename)) {
return self::reject("Cannot read credentials from $filename");
}
$profiles = self::loadProfiles($filename);
if (!isset($profiles[$ssoProfileName])) {
return self::reject("Profile {$ssoProfileName} does not exist in {$filename}.");
}
$ssoProfile = $profiles[$ssoProfileName];
if (empty($ssoProfile['sso_start_url'])
|| empty($ssoProfile['sso_region'])
|| empty($ssoProfile['sso_account_id'])
|| empty($ssoProfile['sso_role_name'])
) {
return self::reject(
"Profile {$ssoProfileName} in {$filename} must contain the following keys: "
. "sso_start_url, sso_region, sso_account_id, and sso_role_name."
);
}
$tokenLocation = self::getHomeDir()
. '/.aws/sso/cache/'
. utf8_encode(sha1($ssoProfile['sso_start_url']))
. ".json";
if (!is_readable($tokenLocation)) {
return self::reject("Unable to read token file at $tokenLocation");
}
$tokenData = json_decode(file_get_contents($tokenLocation), true);
if (empty($tokenData['accessToken']) || empty($tokenData['expiresAt'])) {
return self::reject(
"Token file at {$tokenLocation} must contain an access token and an expiration"
);
}
try {
$expiration = (new DateTimeResult($tokenData['expiresAt']))->getTimestamp();
} catch (\Exception $e) {
return self::reject("Cached SSO credentials returned an invalid expiration");
}
$now = time();
if ($expiration < $now) {
return self::reject("Cached SSO credentials returned expired credentials");
}
$ssoClient = null;
if (empty($config['ssoClient'])) {
$ssoClient = new Aws\SSO\SSOClient([
'region' => $ssoProfile['sso_region'],
'version' => '2019-06-10',
'credentials' => false
]);
} else {
$ssoClient = $config['ssoClient'];
}
$ssoResponse = $ssoClient->getRoleCredentials([
'accessToken' => $tokenData['accessToken'],
'accountId' => $ssoProfile['sso_account_id'],
'roleName' => $ssoProfile['sso_role_name']
]);
$ssoCredentials = $ssoResponse['roleCredentials'];
return Promise\promise_for(
new Credentials(
$ssoCredentials['accessKeyId'],
$ssoCredentials['secretAccessKey'],
$ssoCredentials['sessionToken'],
$expiration
)
);
};
}
/**
* Credential provider that creates credentials using
* ecs credentials by a GET request, whose uri is specified
* by environment variable
*
* @param array $config Array of configuration data.
*
* @return EcsCredentialProvider
* @see Aws\Credentials\EcsCredentialProvider for $config details.
*/
public static function ecsCredentials(array $config = [])
{
return new EcsCredentialProvider($config);
}
/**
* Credential provider that creates credentials using assume role
*
* @param array $config Array of configuration data
* @return callable
* @see Aws\Credentials\AssumeRoleCredentialProvider for $config details.
*/
public static function assumeRole(array $config=[])
{
return new AssumeRoleCredentialProvider($config);
}
/**
* Credential provider that creates credentials by assuming role from a
* Web Identity Token
*
* @param array $config Array of configuration data
* @return callable
* @see Aws\Credentials\AssumeRoleWithWebIdentityCredentialProvider for
* $config details.
*/
public static function assumeRoleWithWebIdentityCredentialProvider(array $config = [])
{
return function () use ($config) {
$arnFromEnv = getenv(self::ENV_ARN);
$tokenFromEnv = getenv(self::ENV_TOKEN_FILE);
$stsClient = isset($config['stsClient'])
? $config['stsClient']
: null;
$region = isset($config['region'])
? $config['region']
: null;
if ($tokenFromEnv && $arnFromEnv) {
$sessionName = getenv(self::ENV_ROLE_SESSION_NAME)
? getenv(self::ENV_ROLE_SESSION_NAME)
: null;
$provider = new AssumeRoleWithWebIdentityCredentialProvider([
'RoleArn' => $arnFromEnv,
'WebIdentityTokenFile' => $tokenFromEnv,
'SessionName' => $sessionName,
'client' => $stsClient,
'region' => $region
]);
return $provider();
}
$profileName = getenv(self::ENV_PROFILE) ?: 'default';
if (isset($config['filename'])) {
$profiles = self::loadProfiles($config['filename']);
} else {
$profiles = self::loadDefaultProfiles();
}
if (isset($profiles[$profileName])) {
$profile = $profiles[$profileName];
if (isset($profile['region'])) {
$region = $profile['region'];
}
if (isset($profile['web_identity_token_file'])
&& isset($profile['role_arn'])
) {
$sessionName = isset($profile['role_session_name'])
? $profile['role_session_name']
: null;
$provider = new AssumeRoleWithWebIdentityCredentialProvider([
'RoleArn' => $profile['role_arn'],
'WebIdentityTokenFile' => $profile['web_identity_token_file'],
'SessionName' => $sessionName,
'client' => $stsClient,
'region' => $region
]);
return $provider();
}
} else {
return self::reject("Unknown profile: $profileName");
}
return self::reject("No RoleArn or WebIdentityTokenFile specified");
};
}
/**
* Credentials provider that creates credentials using an ini file stored
* in the current user's home directory. A source can be provided
* in this file for assuming a role using the credential_source config option.
*
* @param string|null $profile Profile to use. If not specified will use
* the "default" profile in "~/.aws/credentials".
* @param string|null $filename If provided, uses a custom filename rather
* than looking in the home directory.
* @param array|null $config If provided, may contain the following:
* preferStaticCredentials: If true, prefer static
* credentials to role_arn if both are present
* disableAssumeRole: If true, disable support for
* roles that assume an IAM role. If true and role profile
* is selected, an error is raised.
* stsClient: StsClient used to assume role specified in profile
*
* @return callable
*/
public static function ini($profile = null, $filename = null, array $config = [])
{
$filename = self::getFileName($filename);
$profile = $profile ?: (getenv(self::ENV_PROFILE) ?: 'default');
return function () use ($profile, $filename, $config) {
$preferStaticCredentials = isset($config['preferStaticCredentials'])
? $config['preferStaticCredentials']
: false;
$disableAssumeRole = isset($config['disableAssumeRole'])
? $config['disableAssumeRole']
: false;
$stsClient = isset($config['stsClient']) ? $config['stsClient'] : null;
if (!is_readable($filename)) {
return self::reject("Cannot read credentials from $filename");
}
$data = self::loadProfiles($filename);
if ($data === false) {
return self::reject("Invalid credentials file: $filename");
}
if (!isset($data[$profile])) {
return self::reject("'$profile' not found in credentials file");
}
/*
In the CLI, the presence of both a role_arn and static credentials have
different meanings depending on how many profiles have been visited. For
the first profile processed, role_arn takes precedence over any static
credentials, but for all subsequent profiles, static credentials are
used if present, and only in their absence will the profile's
source_profile and role_arn keys be used to load another set of
credentials. This bool is intended to yield compatible behaviour in this
sdk.
*/
$preferStaticCredentialsToRoleArn = ($preferStaticCredentials
&& isset($data[$profile]['aws_access_key_id'])
&& isset($data[$profile]['aws_secret_access_key']));
if (isset($data[$profile]['role_arn'])
&& !$preferStaticCredentialsToRoleArn
) {
if ($disableAssumeRole) {
return self::reject(
"Role assumption profiles are disabled. "
. "Failed to load profile " . $profile);
}
return self::loadRoleProfile(
$data,
$profile,
$filename,
$stsClient,
$config
);
}
if (!isset($data[$profile]['aws_access_key_id'])
|| !isset($data[$profile]['aws_secret_access_key'])
) {
return self::reject("No credentials present in INI profile "
. "'$profile' ($filename)");
}
if (empty($data[$profile]['aws_session_token'])) {
$data[$profile]['aws_session_token']
= isset($data[$profile]['aws_security_token'])
? $data[$profile]['aws_security_token']
: null;
}
return Promise\promise_for(
new Credentials(
$data[$profile]['aws_access_key_id'],
$data[$profile]['aws_secret_access_key'],
$data[$profile]['aws_session_token']
)
);
};
}
/**
* Credentials provider that creates credentials using a process configured in
* ini file stored in the current user's home directory.
*
* @param string|null $profile Profile to use. If not specified will use
* the "default" profile in "~/.aws/credentials".
* @param string|null $filename If provided, uses a custom filename rather
* than looking in the home directory.
*
* @return callable
*/
public static function process($profile = null, $filename = null)
{
$filename = self::getFileName($filename);
$profile = $profile ?: (getenv(self::ENV_PROFILE) ?: 'default');
return function () use ($profile, $filename) {
if (!is_readable($filename)) {
return self::reject("Cannot read process credentials from $filename");
}
$data = \Aws\parse_ini_file($filename, true, INI_SCANNER_RAW);
if ($data === false) {
return self::reject("Invalid credentials file: $filename");
}
if (!isset($data[$profile])) {
return self::reject("'$profile' not found in credentials file");
}
if (!isset($data[$profile]['credential_process'])) {
return self::reject("No credential_process present in INI profile "
. "'$profile' ($filename)");
}
$credentialProcess = $data[$profile]['credential_process'];
$json = shell_exec($credentialProcess);
$processData = json_decode($json, true);
// Only support version 1
if (isset($processData['Version'])) {
if ($processData['Version'] !== 1) {
return self::reject("credential_process does not return Version == 1");
}
}
if (!isset($processData['AccessKeyId'])
|| !isset($processData['SecretAccessKey']))
{
return self::reject("credential_process does not return valid credentials");
}
if (isset($processData['Expiration'])) {
try {
$expiration = new DateTimeResult($processData['Expiration']);
} catch (\Exception $e) {
return self::reject("credential_process returned invalid expiration");
}
$now = new DateTimeResult();
if ($expiration < $now) {
return self::reject("credential_process returned expired credentials");
}
$expires = $expiration->getTimestamp();
} else {
$expires = null;
}
if (empty($processData['SessionToken'])) {
$processData['SessionToken'] = null;
}
return Promise\promise_for(
new Credentials(
$processData['AccessKeyId'],
$processData['SecretAccessKey'],
$processData['SessionToken'],
$expires
)
);
};
}
/**
* Assumes role for profile that includes role_arn
*
* @return callable
*/
private static function loadRoleProfile(
$profiles,
$profileName,
$filename,
$stsClient,
$config = []
) {
$roleProfile = $profiles[$profileName];
$roleArn = isset($roleProfile['role_arn']) ? $roleProfile['role_arn'] : '';
$roleSessionName = isset($roleProfile['role_session_name'])
? $roleProfile['role_session_name']
: 'aws-sdk-php-' . round(microtime(true) * 1000);
if (
empty($roleProfile['source_profile'])
== empty($roleProfile['credential_source'])
) {
return self::reject("Either source_profile or credential_source must be set " .
"using profile " . $profileName . ", but not both."
);
}
$sourceProfileName = "";
if (!empty($roleProfile['source_profile'])) {
$sourceProfileName = $roleProfile['source_profile'];
if (!isset($profiles[$sourceProfileName])) {
return self::reject("source_profile " . $sourceProfileName
. " using profile " . $profileName . " does not exist"
);
}
if (isset($config['visited_profiles']) &&
in_array($roleProfile['source_profile'], $config['visited_profiles'])
) {
return self::reject("Circular source_profile reference found.");
}
$config['visited_profiles'] [] = $roleProfile['source_profile'];
} else {
if (empty($roleArn)) {
return self::reject(
"A role_arn must be provided with credential_source in " .
"file {$filename} under profile {$profileName} "
);
}
}
if (empty($stsClient)) {
$sourceRegion = isset($profiles[$sourceProfileName]['region'])
? $profiles[$sourceProfileName]['region']
: 'us-east-1';
$config['preferStaticCredentials'] = true;
$sourceCredentials = null;
if (!empty($roleProfile['source_profile'])){
$sourceCredentials = call_user_func(
CredentialProvider::ini($sourceProfileName, $filename, $config)
)->wait();
} else {
$sourceCredentials = self::getCredentialsFromSource(
$profileName,
$filename
);
}
$stsClient = new StsClient([
'credentials' => $sourceCredentials,
'region' => $sourceRegion,
'version' => '2011-06-15',
]);
}
$result = $stsClient->assumeRole([
'RoleArn' => $roleArn,
'RoleSessionName' => $roleSessionName
]);
$credentials = $stsClient->createCredentials($result);
return Promise\promise_for($credentials);
}
/**
* Gets the environment's HOME directory if available.
*
* @return null|string
*/
private static function getHomeDir()
{
// On Linux/Unix-like systems, use the HOME environment variable
if ($homeDir = getenv('HOME')) {
return $homeDir;
}
// Get the HOMEDRIVE and HOMEPATH values for Windows hosts
$homeDrive = getenv('HOMEDRIVE');
$homePath = getenv('HOMEPATH');
return ($homeDrive && $homePath) ? $homeDrive . $homePath : null;
}
/**
* Gets profiles from specified $filename, or default ini files.
*/
private static function loadProfiles($filename)
{
$profileData = \Aws\parse_ini_file($filename, true, INI_SCANNER_RAW);
// If loading .aws/credentials, also load .aws/config when AWS_SDK_LOAD_NONDEFAULT_CONFIG is set
if ($filename === self::getHomeDir() . '/.aws/credentials'
&& getenv('AWS_SDK_LOAD_NONDEFAULT_CONFIG')
) {
$configFilename = self::getHomeDir() . '/.aws/config';
$configProfileData = \Aws\parse_ini_file($configFilename, true, INI_SCANNER_RAW);
foreach ($configProfileData as $name => $profile) {
// standardize config profile names
$name = str_replace('profile ', '', $name);
if (!isset($profileData[$name])) {
$profileData[$name] = $profile;
}
}
}
return $profileData;
}
/**
* Gets profiles from ~/.aws/credentials and ~/.aws/config ini files
*/
private static function loadDefaultProfiles() {
$profiles = [];
$credFile = self::getHomeDir() . '/.aws/credentials';
$configFile = self::getHomeDir() . '/.aws/config';
if (file_exists($credFile)) {
$profiles = \Aws\parse_ini_file($credFile, true, INI_SCANNER_RAW);
}
if (file_exists($configFile)) {
$configProfileData = \Aws\parse_ini_file($configFile, true, INI_SCANNER_RAW);
foreach ($configProfileData as $name => $profile) {
// standardize config profile names
$name = str_replace('profile ', '', $name);
if (!isset($profiles[$name])) {
$profiles[$name] = $profile;
}
}
}
return $profiles;
}
public static function getCredentialsFromSource(
$profileName = '',
$filename = '',
$config = []
) {
$data = self::loadProfiles($filename);
$credentialSource = !empty($data[$profileName]['credential_source'])
? $data[$profileName]['credential_source']
: null;
$credentialsPromise = null;
switch ($credentialSource) {
case 'Environment':
$credentialsPromise = self::env();
break;
case 'Ec2InstanceMetadata':
$credentialsPromise = self::instanceProfile($config);
break;
case 'EcsContainer':
$credentialsPromise = self::ecsCredentials($config);
break;
default:
throw new CredentialsException(
"Invalid credential_source found in config file: {$credentialSource}. Valid inputs "
. "include Environment, Ec2InstanceMetadata, and EcsContainer."
);
}
$credentialsResult = null;
try {
$credentialsResult = $credentialsPromise()->wait();
} catch (\Exception $reason) {
return self::reject(
"Unable to successfully retrieve credentials from the source specified in the"
. " credentials file: {$credentialSource}; failure message was: "
. $reason->getMessage()
);
}
return function () use ($credentialsResult) {
return Promise\promise_for($credentialsResult);
};
}
private static function reject($msg)
{
return new Promise\RejectedPromise(new CredentialsException($msg));
}
/**
* @param $filename
* @return string
*/
private static function getFileName($filename)
{
if (!isset($filename)) {
$filename = getenv(self::ENV_SHARED_CREDENTIALS_FILE) ?:
(self::getHomeDir() . '/.aws/credentials');
}
return $filename;
}
}