Apply IP blocks to X-Forwarded-For header
authorSkizzerz <skizzerz@gmail.com>
Sat, 17 Nov 2012 23:23:09 +0000 (17:23 -0600)
committercsteipp <csteipp@wikimedia.org>
Fri, 29 Mar 2013 18:29:17 +0000 (11:29 -0700)
Adds a new configuration variable ($wgApplyIpBlocksToXff), which when
enabled will scan the XFF header for IP addresses and check if any of
them have been blocked. $wgApplyIpBlocksToXff is disabled by default.

Bug: 23343
Change-Id: I3e38b94d10600a60d2d4857de54307f34c4662c4

RELEASE-NOTES-1.21
includes/Block.php
includes/DefaultSettings.php
includes/User.php
languages/messages/MessagesEn.php
languages/messages/MessagesQqq.php
maintenance/language/messages.inc
tests/phpunit/includes/BlockTest.php

index 56d812c..ff0569e 100644 (file)
@@ -125,6 +125,8 @@ production.
   correctly.
 * (bug 45803) Whitespace within == Headline == syntax and within <hN> headings
   is now non-significant and not preserved in the HTML output.
+* (bug 23343) Implemented ability to apply IP blocks to the contents of X-Forwarded-For headers
+  by adding a new configuration variable $wgApplyIpBlocksToXff (disabled by default).
 
 === Bug fixes in 1.21 ===
 * (bug 40353) SpecialDoubleRedirect should support interwiki redirects.
index 7ee36ce..fc8ece6 100644 (file)
@@ -1074,6 +1074,187 @@ class Block {
                return null;
        }
 
+
+       /**
+        * Get all blocks that match any IP from an array of IP addresses. Blocks are
+        * sorted so that hard blocks are before soft blocks, and blocks that disable
+        * account creation are before those that don't.
+        *
+        * @param Array $ipChain list of IPs (strings), usually retrieved from the
+        *         X-Forwarded-For header of the request
+        * @param Bool $isAnon Exclude anonymous-only blocks if false
+        * @param Bool $fromMaster Whether to query the master or slave database
+        * @return Array of Blocks
+        * @since 1.21
+        */
+       public static function getBlocksForIPList( array $ipChain, $isAnon, $fromMaster = false ) {
+               if ( !count( $ipChain ) ) {
+                       return array();
+               }
+
+               wfProfileIn( __METHOD__ );
+               $conds = array();
+               foreach ( array_unique( $ipChain ) as $ipaddr ) {
+                       # Discard invalid IP addresses. Since XFF can be spoofed and we do not
+                       # necessarily trust the header given to us, make sure that we are only
+                       # checking for blocks on well-formatted IP addresses (IPv4 and IPv6).
+                       # Do not treat private IP spaces as special as it may be desirable for wikis
+                       # to block those IP ranges in order to stop misbehaving proxies that spoof XFF.
+                       if ( !IP::isValid( $ipaddr ) ) {
+                               continue;
+                       }
+                       # Don't check trusted IPs (includes local squids which will be in every request)
+                       if ( wfIsTrustedProxy( $ipaddr ) ) {
+                               continue;
+                       }
+                       # Check both the original IP (to check against single blocks), as well as build
+                       # the clause to check for rangeblocks for the given IP.
+                       $conds['ipb_address'][] = $ipaddr;
+                       $conds[] = self::getRangeCond( IP::toHex( $ipaddr ) );
+               }
+
+               if ( !count( $conds ) ) {
+                       wfProfileOut( __METHOD__ );
+                       return array();
+               }
+
+               if ( $fromMaster ) {
+                       $db = wfGetDB( DB_MASTER );
+               } else {
+                       $db = wfGetDB( DB_SLAVE );
+               }
+               $conds = $db->makeList( $conds, LIST_OR );
+               if ( !$isAnon ) {
+                       $conds = array( $conds, 'ipb_anon_only' => 0 );
+               }
+               $selectFields = array_merge(
+                       array( 'ipb_range_start', 'ipb_range_end' ),
+                       Block::selectFields()
+               );
+               $rows = $db->select( 'ipblocks',
+                       $selectFields,
+                       $conds,
+                       __METHOD__,
+                       array( 'ORDER BY' => 'ipb_anon_only ASC, ipb_create_account DESC' )
+               );
+
+               $blocks = array();
+               foreach ( $rows as $row ) {
+                       $block = self::newFromRow( $row );
+                       if ( !$block->deleteIfExpired()  ) {
+                               $blocks[] = $block;
+                       }
+               }
+
+               wfProfileOut( __METHOD__ );
+               return $blocks;
+       }
+
+       /**
+        * From a list of multiple blocks, find the most exact and strongest Block.
+        * The logic for finding the "best" block is:
+        *  - Blocks that match the block's target IP are preferred over ones in a range
+        *  - Hardblocks are chosen over softblocks that prevent account creation
+        *  - Softblocks that prevent account creation are chosen over other softblocks
+        *  - Other softblocks are chosen over autoblocks
+        *  - If there are multiple exact or range blocks at the same level, the one chosen
+        *    is random
+
+        * @param Array $ipChain list of IPs (strings). This is used to determine how "close"
+        *        a block is to the server, and if a block matches exactly, or is in a range.
+        *        The order is furthest from the server to nearest e.g., (Browser, proxy1, proxy2,
+        *        local-squid, ...)
+        * @param Array $block Array of blocks, sorted with hard blocks before soft blocks,
+        *        and ones that disable account creation before those that don't. The db query
+        *        probably had 'ORDER BY' => 'ipb_anon_only ASC, ipb_create_account DESC'
+        * @return Block|null the "best" block from the list
+        */
+       public static function chooseBlock( array $blocks, array $ipChain  ) {
+               if ( !count( $blocks ) ) {
+                       return null;
+               } elseif ( count( $blocks ) == 1 ) {
+                       return $blocks[0];
+               }
+
+               wfProfileIn( __METHOD__ );
+               $blocksListExact = array(
+                       'hard' => false,
+                       'disable_create' => false,
+                       'other' => false,
+                       'auto' => false
+               );
+               $blocksListRange = array(
+                       'hard' => false,
+                       'disable_create' => false,
+                       'other' => false,
+                       'auto' => false
+               );
+               $ipChain = array_reverse( $ipChain );
+
+               foreach ( $blocks as $block ) {
+                       // Stop searching if we have already have a "better" block. This
+                       // is why the order of the blocks matters
+                       if ( !$block->isHardblock() && $blocksListExact['hard'] ) {
+                               break;
+                       } elseif ( !$block->prevents( 'createaccount' ) && $blocksListExact['disable_create'] ) {
+                               break;
+                       }
+
+                       foreach ( $ipChain as $checkip ) {
+                               $checkipHex = IP::toHex( $checkip );
+                               if ( (string)$block->getTarget() === $checkip ) {
+                                       if ( $block->isHardblock() ) {
+                                               $blocksListExact['hard'] = $blocksListExact['hard'] ?: $block;
+                                       } elseif ( $block->prevents( 'createaccount' ) ) {
+                                               $blocksListExact['disable_create'] = $blocksListExact['disable_create'] ?: $block;
+                                       } elseif ( $block->mAuto ) {
+                                               $blocksListExact['auto'] = $blocksListExact['auto'] ?: $block;
+                                       } else {
+                                               $blocksListExact['other'] = $blocksListExact['other'] ?: $block;
+                                       }
+                                       // We found closest exact match in the ip list, so go to the next Block
+                                       break;
+                               } elseif ( array_filter( $blocksListExact ) == array()
+                                       && $block->getRangeStart() <= $checkipHex
+                                       && $block->getRangeEnd() >= $checkipHex
+                               ) {
+                                       if ( $block->isHardblock() ) {
+                                               $blocksListRange['hard'] = $blocksListRange['hard'] ?: $block;
+                                       } elseif ( $block->prevents( 'createaccount' ) ) {
+                                               $blocksListRange['disable_create'] = $blocksListRange['disable_create'] ?: $block;
+                                       } elseif ( $block->mAuto ) {
+                                               $blocksListRange['auto'] = $blocksListRange['auto'] ?: $block;
+                                       } else {
+                                               $blocksListRange['other'] = $blocksListRange['other'] ?: $block;
+                                       }
+                                       break;
+                               }
+                       }
+               }
+
+               if ( array_filter( $blocksListExact ) == array() ) {
+                       $blocksList = &$blocksListRange;
+               } else {
+                       $blocksList = &$blocksListExact;
+               }
+
+               $chosenBlock = null;
+               if ( $blocksList['hard'] ) {
+                       $chosenBlock = $blocksList['hard'];
+               } elseif ( $blocksList['disable_create'] ) {
+                       $chosenBlock = $blocksList['disable_create'];
+               } elseif ( $blocksList['other'] ) {
+                       $chosenBlock = $blocksList['other'];
+               } elseif ( $blocksList['auto'] ) {
+                       $chosenBlock = $blocksList['auto'];
+               } else {
+                       throw new MWException( "Proxy block found, but couldn't be classified." );
+               }
+
+               wfProfileOut( __METHOD__ );
+               return $chosenBlock;
+       }
+
        /**
         * From an existing Block, get the target and the type of target.
         * Note that, except for null, it is always safe to treat the target
index 26fe197..2fce7f7 100644 (file)
@@ -4324,6 +4324,13 @@ $wgSorbsUrl = array();
  */
 $wgProxyWhitelist = array();
 
+/**
+ * Whether to look at the X-Forwarded-For header's list of (potentially spoofed)
+ * IPs and apply IP blocks to them. This allows for IP blocks to work with correctly-configured
+ * (transparent) proxies without needing to block the proxies themselves.
+ */
+$wgApplyIpBlocksToXff = false;
+
 /**
  * Simple rate limiter options to brake edit floods.
  *
index 6b7348a..8809fe9 100644 (file)
@@ -1271,7 +1271,7 @@ class User {
         *                    done against master.
         */
        private function getBlockedStatus( $bFromSlave = true ) {
-               global $wgProxyWhitelist, $wgUser;
+               global $wgProxyWhitelist, $wgUser, $wgApplyIpBlocksToXff;
 
                if ( -1 != $this->mBlockedby ) {
                        return;
@@ -1317,6 +1317,25 @@ class User {
                        }
                }
 
+               # (bug 23343) Apply IP blocks to the contents of XFF headers, if enabled
+               if ( !$block instanceof Block
+                       && $wgApplyIpBlocksToXff
+                       && $ip !== null
+                       && !$this->isAllowed( 'proxyunbannable' )
+                       && !in_array( $ip, $wgProxyWhitelist )
+               ) {
+                       $xff = $this->getRequest()->getHeader( 'X-Forwarded-For' );
+                       $xff = array_map( 'trim', explode( ',', $xff ) );
+                       $xff = array_diff( $xff, array( $ip ) );
+                       $xffblocks = Block::getBlocksForIPList( $xff, $this->isAnon(), !$bFromSlave );
+                       $block = Block::chooseBlock( $xffblocks, $xff );
+                       if ( $block instanceof Block ) {
+                               # Mangle the reason to alert the user that the block
+                               # originated from matching the X-Forwarded-For header.
+                               $block->mReason = wfMessage( 'xffblockreason', $block->mReason )->text();
+                       }
+               }
+
                if ( $block instanceof Block ) {
                        wfDebug( __METHOD__ . ": Found block.\n" );
                        $this->mBlock = $block;
@@ -1330,7 +1349,7 @@ class User {
                        $this->mAllowUsertalk = false;
                }
 
-               # Extensions
+               // Extensions
                wfRunHooks( 'GetBlockedStatus', array( &$this ) );
 
                wfProfileOut( __METHOD__ );
index 52082af..b6fff48 100644 (file)
@@ -3307,6 +3307,7 @@ Please contact your Internet service provider or technical support of your organ
 'sorbsreason'                     => 'Your IP address is listed as an open proxy in the DNSBL used by {{SITENAME}}.',
 'sorbs_create_account_reason'     => 'Your IP address is listed as an open proxy in the DNSBL used by {{SITENAME}}.
 You cannot create an account',
+'xffblockreason'                  => 'An IP address present in the X-Forwarded-For header, either yours or that of a proxy server you are using, has been blocked. The original block reason was: $1',
 'cant-block-while-blocked'        => 'You cannot block other users while you are blocked.',
 'cant-see-hidden-user'            => "The user you are trying to block has already been blocked and hidden.
 Since you do not have the hideuser right, you cannot see or edit the user's block.",
index 14f8b25..700282a 100644 (file)
@@ -5374,6 +5374,9 @@ See also:
 * {{msg-mw|Sorbsreason}}
 * {{msg-mw|Sorbs create account_reason}}',
 'cant-see-hidden-user' => 'Used as (red) error message on [[Special:Block]] when you try to change (as sysop without the hideuser right) the block of a hidden user.',
+'xffblockreason' => "This text is shown to the user as a block reason and describes that the user is being blocked because an IP in the X-Forwarded-For header
+(which lists the user's IP as well as all IPs of the transparent proxy servers they went through) sent when they loaded the page has been blocked:
+* $1 is the original block reason for the IP address matched in the X-Forwarded-For header",
 'ipbblocked' => 'Error message shown when a user tries to alter block settings when they are themselves blocked.',
 'ipbnounblockself' => 'Error message shown when a user without the <tt>unblockself</tt> right tries to unblock themselves.',
 
index 7c16df6..ae33cca 100644 (file)
@@ -2291,6 +2291,7 @@ $wgMessageStructure = array(
                'sorbs',
                'sorbsreason',
                'sorbs_create_account_reason',
+               'xffblockreason',
                'cant-block-while-blocked',
                'cant-see-hidden-user',
                'ipbblocked',
index 19c9b68..704c912 100644 (file)
@@ -228,4 +228,117 @@ class BlockTest extends MediaWikiLangTestCase {
                $this->assertEquals( 'MetaWikiUser', $block->getByName(), 'Correct blocker name' );
                $this->assertEquals( 0, $block->getBy(), 'Correct blocker id' );
        }
+
+       function testBlocksOnXff() {
+
+               $blockList = array(
+                       array( 'target' => '70.2.0.0/16',
+                               'type' =>  Block::TYPE_RANGE,
+                               'desc' => 'Range Hardblock',
+                               'ACDisable' => false,
+                               'isHardblock' => true,
+                               'isAutoBlocking' => false,
+                       ),
+                       array( 'target' => '2001:4860:4001::/48',
+                               'type' =>  Block::TYPE_RANGE,
+                               'desc' => 'Range6 Hardblock',
+                               'ACDisable' => false,
+                               'isHardblock' => true,
+                               'isAutoBlocking' => false,
+                       ),
+                       array( 'target' => '60.2.0.0/16',
+                               'type' =>  Block::TYPE_RANGE,
+                               'desc' => 'Range Softblock with AC Disabled',
+                               'ACDisable' => true,
+                               'isHardblock' => false,
+                               'isAutoBlocking' => false,
+                       ),
+                       array( 'target' => '50.2.0.0/16',
+                               'type' =>  Block::TYPE_RANGE,
+                               'desc' => 'Range Softblock',
+                               'ACDisable' => false,
+                               'isHardblock' => false,
+                               'isAutoBlocking' => false,
+                       ),
+                       array( 'target' => '50.1.1.1',
+                               'type' =>  Block::TYPE_IP,
+                               'desc' => 'Exact Softblock',
+                               'ACDisable' => false,
+                               'isHardblock' => false,
+                               'isAutoBlocking' => false,
+                       ),
+               );
+
+               foreach ( $blockList as $insBlock ) {
+                       $target = $insBlock['target'];
+
+                       if ( $insBlock['type'] === Block::TYPE_IP ) {
+                               $target = User::newFromName( IP::sanitizeIP( $target ), false )->getName();
+                       } elseif ( $insBlock['type'] === Block::TYPE_RANGE ) {
+                               $target = IP::sanitizeRange( $target );
+                       }
+
+                       $block = new Block();
+                       $block->setTarget( $target );
+                       $block->setBlocker( 'testblocker@global' );
+                       $block->mReason = $insBlock['desc'];
+                       $block->mExpiry = 'infinity';
+                       $block->prevents( $insBlock['ACDisable'] );
+                       $block->isHardblock( $insBlock['isHardblock'] );
+                       $block->isAutoblocking( $insBlock['isAutoBlocking'] );
+                       $block->insert();
+               }
+
+               $xffHeaders = array(
+                       array( 'xff' => '1.2.3.4, 70.2.1.1, 60.2.1.1, 2.3.4.5',
+                               'count' => 2,
+                               'result' => 'Range Hardblock'
+                       ),
+                       array( 'xff' => '1.2.3.4, 50.2.1.1, 60.2.1.1, 2.3.4.5',
+                               'count' => 2,
+                               'result' => 'Range Softblock with AC Disabled'
+                       ),
+                       array( 'xff' => '1.2.3.4, 70.2.1.1, 50.1.1.1, 2.3.4.5',
+                               'count' => 2,
+                               'result' => 'Exact Softblock'
+                       ),
+                       array( 'xff' => '1.2.3.4, 70.2.1.1, 50.2.1.1, 50.1.1.1, 2.3.4.5',
+                               'count' => 3,
+                               'result' => 'Exact Softblock'
+                       ),
+                       array( 'xff' => '1.2.3.4, 70.2.1.1, 50.2.1.1, 2.3.4.5',
+                               'count' => 2,
+                               'result' => 'Range Hardblock'
+                       ),
+                       array( 'xff' => '1.2.3.4, 70.2.1.1, 60.2.1.1, 2.3.4.5',
+                               'count' => 2,
+                               'result' => 'Range Hardblock'
+                       ),
+                       array( 'xff' => '50.2.1.1, 60.2.1.1, 2.3.4.5',
+                               'count' => 2,
+                               'result' => 'Range Softblock with AC Disabled'
+                       ),
+                       array( 'xff' => '1.2.3.4, 50.1.1.1, 60.2.1.1, 2.3.4.5',
+                               'count' => 2,
+                               'result' => 'Exact Softblock'
+                       ),
+                       array( 'xff' => '1.2.3.4, <$A_BUNCH-OF{INVALID}TEXT\>, 60.2.1.1, 2.3.4.5',
+                               'count' => 1,
+                               'result' => 'Range Softblock with AC Disabled'
+                       ),
+                       array( 'xff' => '1.2.3.4, 50.2.1.1, 2001:4860:4001:802::1003, 2.3.4.5',
+                               'count' => 2,
+                               'result' => 'Range6 Hardblock'
+                       ),
+               );
+
+               foreach ( $xffHeaders as $test ) {
+                       $list = array_map( 'trim', explode( ',', $test['xff'] ) );
+                       $xffblocks = Block::getBlocksForIPList( $list, true );
+                       $this->assertEquals( $test['count'], count( $xffblocks ), 'Number of blocks for ' . $test['xff'] );
+                       $block = Block::chooseBlock( $xffblocks, $list );
+                       $this->assertEquals( $test['result'], $block->mReason, 'Correct block type for XFF header ' . $test['xff'] );
+               }
+
+       }
 }