From 92cdd4cc7f6955760236e134126d8a68efa13360 Mon Sep 17 00:00:00 2001
From: Andreas Baumann <mail@andreasbaumann.cc>
Date: Wed, 12 Feb 2020 19:21:35 +0100
Subject: hand-picked changes for better password functions from tyzoids branch

---
 include/functions.php | 91 ++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 90 insertions(+), 1 deletion(-)

(limited to 'include/functions.php')

diff --git a/include/functions.php b/include/functions.php
index ace2934..8e9265c 100644
--- a/include/functions.php
+++ b/include/functions.php
@@ -164,7 +164,7 @@ function authenticate_user($user, $password, $password_is_hash = false)
 	$pun_user = $db->fetch_assoc($result);
 
 	$is_password_authorized = pun_hash_equals($password, $pun_user['password']);
-	$is_hash_authorized = pun_hash_equals(pun_hash($password), $pun_user['password']);
+	$is_hash_authorized = pun_password_verify($password, $pun_user['password']);
 
 	if (!isset($pun_user['id']) ||
 		($password_is_hash && !$is_password_authorized ||
@@ -1130,6 +1130,95 @@ function validate_redirect($redirect_url, $fallback_url)
 }
 
 
+//
+// Compute the hash of a password
+// using a secure password hashing algorithm, if available
+// As of PHP 7.2, this is BLOWFISH.
+// This function will fall back to unsecure defaults if
+// password_hash does not exist (requires >=PHP5.5)
+//
+function pun_password_hash($pass)
+{
+ global $password_hash_cost;
+
+ $cost = $password_hash_cost;
+ if (empty($cost))
+  $cost = 10;
+
+ if (function_exists('password_hash'))
+  return password_hash($pass, PASSWORD_DEFAULT, array('cost' => $cost));
+ else
+  return pun_hash($pass);
+}
+
+
+//
+// Verify that $pass and $hash match
+// This supports any password hashing algorithm
+// used by pun_password_hash
+//
+function pun_password_verify($pass, $hash)
+{
+ if (!empty($hash) && $hash[0] !== '$')
+  return pun_hash_equals(pun_hash($pass), $hash);
+ else
+  return password_verify($pass, $hash);
+}
+
+//
+// Verify that $pass and $hash match
+// This supports any password hashing algorithm
+// used by pun_password_hash, but is also
+// backwards-compatable with older versions of this software.
+//
+function pun_password_verify_legacy($pass, $hash, $salt = null)
+{
+ // MD5 from 1.2
+ if (strlen($hash) < 40)
+  return pun_hash_equals(md5($pass), $hash);
+
+ // SHA1-With-Salt from 1.3
+ if (!empty($salt))
+  return pun_hash_equals(sha1($salt . sha1($pass)), $hash);
+
+ // SHA1-Without-Salt from 1.4
+ if (strlen($hash) == 40)
+  return pun_hash_equals(sha1($pass), $hash);
+
+ // Support current password standard
+ return pun_password_verify($pass, $hash);
+}
+
+
+//
+// Check if $hash is outdated and needs to be rehashed
+//
+function pun_password_needs_rehash($hash)
+{
+ global $password_hash_cost;
+
+ // Determine appropriate cost
+ $cost = $password_hash_cost;
+ if (empty($cost))
+  $cost = 10;
+
+ // Check for legacy md5 hash
+ if (strlen($hash) < 40)
+  return true;
+
+ // Check for legacy sha1 hash. Note: legacy sha1 is used
+ // if password_hash is not available
+ if (function_exists('password_hash') && strlen($hash) == 40)
+  return true;
+
+ // Check for out-of-date hash type or cost
+ if (function_exists('password_needs_rehash'))
+  return password_needs_rehash($hash, PASSWORD_DEFAULT, array('cost' => $cost));
+
+ return false;
+}
+
+
 //
 // Generate a random password of length $len
 // Compatibility wrapper for random_key
-- 
cgit v1.2.3-54-g00ecf