1 files changed, 111 insertions, 29 deletions

diff --git a/system/core/Input.php b/system/core/Input.php
index 162e40c85..ec935d531 100644
--- a/system/core/Input.php
+++ b/system/core/Input.php
@@ -328,39 +328,121 @@ class CI_Input {
 			return $this->ip_address;
 		}
 
-		if (config_item('proxy_ips') != '' && $this->server('HTTP_X_FORWARDED_FOR') && $this->server('REMOTE_ADDR'))
+		$proxy_ips = config_item('proxy_ips');
+		if ( ! empty($proxy_ips) && ! is_array($proxy_ips))
 		{
-			$proxies = preg_split('/[\s,]/', config_item('proxy_ips'), -1, PREG_SPLIT_NO_EMPTY);
-			$proxies = is_array($proxies) ? $proxies : array($proxies);
-
-			$this->ip_address = in_array($_SERVER['REMOTE_ADDR'], $proxies) ? $_SERVER['HTTP_X_FORWARDED_FOR'] : $_SERVER['REMOTE_ADDR'];
-		}
-		elseif ( ! $this->server('HTTP_CLIENT_IP') && $this->server('REMOTE_ADDR'))
-		{
-			$this->ip_address = $_SERVER['REMOTE_ADDR'];
-		}
-		elseif ($this->server('REMOTE_ADDR') && $this->server('HTTP_CLIENT_IP'))
-		{
-			$this->ip_address = $_SERVER['HTTP_CLIENT_IP'];
-		}
-		elseif ($this->server('HTTP_CLIENT_IP'))
-		{
-			$this->ip_address = $_SERVER['HTTP_CLIENT_IP'];
-		}
-		elseif ($this->server('HTTP_X_FORWARDED_FOR'))
-		{
-			$this->ip_address = $_SERVER['HTTP_X_FORWARDED_FOR'];
+			$proxy_ips = explode(',', str_replace(' ', '', $proxy_ips));
 		}
 
-		if ($this->ip_address === FALSE)
-		{
-			return $this->ip_address = '0.0.0.0';
-		}
+		$this->ip_address = $this->server('REMOTE_ADDR');
 
-		if (strpos($this->ip_address, ',') !== FALSE)
+		if ($proxy_ips)
 		{
-			$x = explode(',', $this->ip_address);
-			$this->ip_address = trim(end($x));
+			foreach (array('HTTP_X_FORWARDED_FOR', 'HTTP_CLIENT_IP', 'HTTP_X_CLIENT_IP', 'HTTP_X_CLUSTER_CLIENT_IP') as $header)
+			{
+				if (($spoof = $this->server($header)) !== NULL)
+				{
+					// Some proxies typically list the whole chain of IP
+					// addresses through which the client has reached us.
+					// e.g. client_ip, proxy_ip1, proxy_ip2, etc.
+					if (strpos($spoof, ',') !== FALSE)
+					{
+						$spoof = explode(',', $spoof, 2);
+						$spoof = $spoof[0];
+					}
+
+					if ( ! $this->valid_ip($spoof))
+					{
+						$spoof = NULL;
+					}
+					else
+					{
+						break;
+					}
+				}
+			}
+
+			if ($spoof)
+			{
+				for ($i = 0, $c = count($proxy_ips); $i < $c; $i++)
+				{
+					// Check if we have an IP address or a subnet
+					if (strpos($proxy_ips[$i], '/') === FALSE)
+					{
+						// An IP address (and not a subnet) is specified.
+						// We can compare right away.
+						if ($proxy_ips[$i] === $this->ip_address)
+						{
+							$this->ip_address = $spoof;
+							break;
+						}
+
+						continue;
+					}
+
+					// We have a subnet ... now the heavy lifting begins
+					isset($separator) OR $separator = $this->valid_ip($this->ip_address, 'ipv6') ? ':' : '.';
+
+					// If the proxy entry doesn't match the IP protocol - skip it
+					if (strpos($proxy_ips[$i], $separator) === FALSE)
+					{
+						continue;
+					}
+
+					// Convert the REMOTE_ADDR IP address to binary, if needed
+					if ( ! isset($ip, $sprintf))
+					{
+						if ($separator === ':')
+						{
+							// Make sure we're have the "full" IPv6 format
+							$ip = explode(':',
+								str_replace('::',
+									str_repeat(':', 9 - substr_count($this->ip_address, ':')),
+									$this->ip_address
+								)
+							);
+
+							for ($i = 0; $i < 8; $i++)
+							{
+								$ip[$i] = intval($ip[$i], 16);
+							}
+
+							$sprintf = '%016b%016b%016b%016b%016b%016b%016b%016b';
+						}
+						else
+						{
+							$ip = explode('.', $this->ip_address);
+							$sprintf = '%08b%08b%08b%08b';
+						}
+
+						$ip = vsprintf($sprintf, $ip);
+					}
+
+					// Split the netmask length off the network address
+					list($netaddr, $masklen) = explode('/', $proxy_ips[$i], 2);
+
+					// Again, an IPv6 address is most likely in a compressed form
+					if ($separator === ':')
+					{
+						$netaddr = explode(':', str_replace('::', str_repeat(':', 9 - substr_count($netaddr, ':')), $netaddr));
+						for ($i = 0; $i < 8; $i++)
+						{
+							$netaddr[$i] = intval($netaddr[$i], 16);
+						}
+					}
+					else
+					{
+						$netaddr = explode('.', $netaddr);
+					}
+
+					// Convert to binary and finally compare
+					if (strncmp($ip, vsprintf($sprintf, $netaddr), $masklen) === 0)
+					{
+						$this->ip_address = $spoof;
+						break;
+					}
+				}
+			}
 		}
 
 		if ( ! $this->valid_ip($this->ip_address))
@@ -518,7 +600,7 @@ class CI_Input {
 		$_SERVER['PHP_SELF'] = strip_tags($_SERVER['PHP_SELF']);
 
 		// CSRF Protection check
-		if ($this->_enable_csrf === TRUE)
+		if ($this->_enable_csrf === TRUE && ! $this->is_cli_request())
 		{
 			$this->security->csrf_verify();
 		}