Merge pull request #19023 from nextcloud/enh+fix/17131/hasher-config

expose Argon2 options (as we did for bcrypt)

config/config.sample.php

@@ -1433,6 +1433,37 @@ $CONFIG = array(
  */
 'tempdirectory' => '/tmp/nextcloudtemp',
 
+/**
+ * Hashing
+ *
+ * Nextcloud uses the Argon2 algorithm (with PHP >= 7.2) to create hashes by its
+ * own and exposes its configuration options as following. More information can
+ * be found at: https://www.php.net/manual/en/function.password-hash.php
+ */
+
+/**
+ * The allowed maximum memory in KiB to be used by the algorithm for computing a
+ * hash. The smallest possible value is 8. Values that undershoot the minimum
+ * will be ignored in favor of the default.
+ */
+'hashingMemoryCost' => PASSWORD_ARGON2_DEFAULT_MEMORY_COST,
+
+/**
+ * The allowed maximum time in seconds that can be used by the algorithm for
+ * computing a hash. The value must be an integer, and the minimum value is 1.
+ * Values that undershoot the minimum will be ignored in favor of the default.
+ */
+'hashingTimeCost' => PASSWORD_ARGON2_DEFAULT_TIME_COST,
+
+/**
+ * The allowed number of CPU threads that can be used by the algorithm for
+ * computing a hash. The value must be an integer, and the minimum value is 1.
+ * Rationally it does not help to provide a number higher than the available
+ * threads on the machine. Values that undershoot the minimum will be ignored
+ * in favor of the default.
+ */
+'hashingThreads' => PASSWORD_ARGON2_DEFAULT_THREADS,
+
 /**
  * The hashing cost used by hashes generated by Nextcloud
  * Using a higher value requires more time and CPU power to calculate the hashes

lib/private/Security/Hasher.php

@@ -63,6 +63,20 @@ class Hasher implements IHasher {
 	public function __construct(IConfig $config) {
 		$this->config = $config;
 
+		if (\defined('PASSWORD_ARGON2I')) {
+			// password_hash fails, when the minimum values are undershot.
+			// In this case, ignore and revert to default
+			if ($this->config->getSystemValueInt('hashingMemoryCost', PASSWORD_ARGON2_DEFAULT_MEMORY_COST) >= 8) {
+				$this->options['memory_cost'] = $this->config->getSystemValueInt('hashingMemoryCost', PASSWORD_ARGON2_DEFAULT_MEMORY_COST);
+			}
+			if ($this->config->getSystemValueInt('hashingTimeCost', PASSWORD_ARGON2_DEFAULT_MEMORY_COST) >= 1) {
+				$this->options['time_cost'] = $this->config->getSystemValueInt('hashingTimeCost', PASSWORD_ARGON2_DEFAULT_TIME_COST);
+			}
+			if ($this->config->getSystemValueInt('hashingThreads', PASSWORD_ARGON2_DEFAULT_MEMORY_COST) >= 1) {
+				$this->options['threads'] = $this->config->getSystemValueInt('hashingThreads', PASSWORD_ARGON2_DEFAULT_THREADS);
+			}
+		}
+
 		$hashingCost = $this->config->getSystemValue('hashingCost', null);
 		if(!\is_null($hashingCost)) {
 			$this->options['cost'] = $hashingCost;