Implement token system to fix CSRF vulnerabilities

Specially crafted pages can force authenticated users to unknowingly perform
actions on the AUR website despite being on an attacker's website. This
cross-site request forgery (CSRF) vulnerability applies to all POST data on
the AUR.

Implement a token system using a double submit cookie. Have a hidden form
value on every page containing POST forms. Use the newly added check_token() to
verify the token sent via POST matches the "AURSID" cookie value. Random
nature of the token limits potential for CSRF.

Signed-off-by: canyonknight <canyonknight@gmail.com>
Signed-off-by: Lukas Fleischer <archlinux@cryptocrack.de>

5 files changed, 61 insertions, 44 deletions

diff --git a/web/html/account.php b/web/html/account.php
index 387fd93..5a0ef50 100644
--- a/web/html/account.php
+++ b/web/html/account.php
@@ -88,11 +88,13 @@ if (isset($_COOKIE["AURSID"])) {
 	} elseif ($action == "UpdateAccount") {
 		# user is submitting their modifications to an existing account
 		#
-		process_account_form($atype, "edit", "UpdateAccount",
-				in_request("U"), in_request("T"), in_request("S"),
-				in_request("E"), in_request("P"), in_request("C"),
-				in_request("R"), in_request("L"), in_request("I"),
-				in_request("ID"));
+		if (check_token()) {
+			process_account_form($atype, "edit", "UpdateAccount",
+					in_request("U"), in_request("T"), in_request("S"),
+					in_request("E"), in_request("P"), in_request("C"),
+					in_request("R"), in_request("L"), in_request("I"),
+					in_request("ID"));
+		}
 
 
 	} else {
diff --git a/web/html/addvote.php b/web/html/addvote.php
index f0e7d31..a5ec4a1 100644
--- a/web/html/addvote.php
+++ b/web/html/addvote.php
@@ -16,7 +16,11 @@ if (isset($_COOKIE["AURSID"])) {
 if ($atype == "Trusted User" OR $atype == "Developer") {
 	$dbh = db_connect();
 
-	if (!empty($_POST['addVote'])) {
+	if (!empty($_POST['addVote']) && !check_token()) {
+		$error = __("Invalid token for user action.");
+	}
+
+	if (!empty($_POST['addVote']) && check_token()) {
 		$error = "";
 
 		if (!empty($_POST['user'])) {
@@ -99,6 +103,7 @@ if ($atype == "Trusted User" OR $atype == "Developer") {
 <b><?php print __('Proposal') ?></b><br />
 <textarea name='agenda' rows='25' cols='80'><?php if (!empty($_POST['agenda'])) { print htmlentities($_POST['agenda']); } ?></textarea><br />
 <input type='hidden' name='addVote' value='1' />
+<input type='hidden' name='token' value='<?php print htmlspecialchars($_COOKIE['AURSID']) ?>' />
 <input type='submit' class='button' value='<?php print __('Submit'); ?>' />
 </p>
 </form>
diff --git a/web/html/packages.php b/web/html/packages.php
index dc06c7e..7f31d3d 100644
--- a/web/html/packages.php
+++ b/web/html/packages.php
@@ -36,46 +36,48 @@ if (isset($_POST['IDs'])) {
 
 # Determine what action to do
 $output = "";
-if (current_action("do_Flag")) {
-	$output = pkg_flag($atype, $ids, true);
-} elseif (current_action("do_UnFlag")) {
-	$output = pkg_flag($atype, $ids, False);
-} elseif (current_action("do_Adopt")) {
-	$output = pkg_adopt($atype, $ids, true);
-} elseif (current_action("do_Disown")) {
-	$output = pkg_adopt($atype, $ids, False);
-} elseif (current_action("do_Vote")) {
-	$output = pkg_vote($atype, $ids, true);
-} elseif (current_action("do_UnVote")) {
-	$output = pkg_vote($atype, $ids, False);
-} elseif (current_action("do_Delete")) {
-	if (isset($_POST['confirm_Delete'])) {
-		if (!isset($_POST['merge_Into']) || empty($_POST['merge_Into'])) {
-			$output = pkg_delete($atype, $ids, NULL);
-			unset($_GET['ID']);
-		}
-		else {
-			$mergepkgid = pkgid_from_name($_POST['merge_Into']);
-			if ($mergepkgid) {
-				$output = pkg_delete($atype, $ids, $mergepkgid);
+if (check_token()) {
+	if (current_action("do_Flag")) {
+		$output = pkg_flag($atype, $ids, true);
+	} elseif (current_action("do_UnFlag")) {
+		$output = pkg_flag($atype, $ids, False);
+	} elseif (current_action("do_Adopt")) {
+		$output = pkg_adopt($atype, $ids, true);
+	} elseif (current_action("do_Disown")) {
+		$output = pkg_adopt($atype, $ids, False);
+	} elseif (current_action("do_Vote")) {
+		$output = pkg_vote($atype, $ids, true);
+	} elseif (current_action("do_UnVote")) {
+		$output = pkg_vote($atype, $ids, False);
+	} elseif (current_action("do_Delete")) {
+		if (isset($_POST['confirm_Delete'])) {
+			if (!isset($_POST['merge_Into']) || empty($_POST['merge_Into'])) {
+				$output = pkg_delete($atype, $ids, NULL);
 				unset($_GET['ID']);
 			}
 			else {
-				$output = __("Cannot find package to merge votes and comments into.");
+				$mergepkgid = pkgid_from_name($_POST['merge_Into']);
+				if ($mergepkgid) {
+					$output = pkg_delete($atype, $ids, $mergepkgid);
+					unset($_GET['ID']);
+				}
+				else {
+					$output = __("Cannot find package to merge votes and comments into.");
+				}
 			}
 		}
+		else {
+			$output = __("The selected packages have not been deleted, check the confirmation checkbox.");
+		}
+	} elseif (current_action("do_Notify")) {
+		$output = pkg_notify($atype, $ids);
+	} elseif (current_action("do_UnNotify")) {
+		$output = pkg_notify($atype, $ids, False);
+	} elseif (current_action("do_DeleteComment")) {
+		$output = pkg_delete_comment($atype);
+	} elseif (current_action("do_ChangeCategory")) {
+		$output = pkg_change_category($atype);
 	}
-	else {
-		$output = __("The selected packages have not been deleted, check the confirmation checkbox.");
-	}
-} elseif (current_action("do_Notify")) {
-	$output = pkg_notify($atype, $ids);
-} elseif (current_action("do_UnNotify")) {
-	$output = pkg_notify($atype, $ids, False);
-} elseif (current_action("do_DeleteComment")) {
-	$output = pkg_delete_comment($atype);
-} elseif (current_action("do_ChangeCategory")) {
-	$output = pkg_change_category($atype);
 }
 
 html_header($title);
diff --git a/web/html/pkgsubmit.php b/web/html/pkgsubmit.php
index 539f056..c566cb4 100644
--- a/web/html/pkgsubmit.php
+++ b/web/html/pkgsubmit.php
@@ -27,9 +27,16 @@ if ($uid):
 
 	if (isset($_REQUEST['pkgsubmit'])) {
 
+		# Make sure authenticated user submitted the package themselves
+		if (!check_token()) {
+			$error = __("Invalid token for user action.");
+		}
+
 		# Before processing, make sure we even have a file
-		if ($_FILES['pfile']['size'] == 0){
-			$error = __("Error - No file uploaded");
+		if (!$error) {
+			if ($_FILES['pfile']['size'] == 0){
+				$error = __("Error - No file uploaded");
+			}
 		}
 
 		# Check whether the file is gzip'ed
@@ -448,7 +455,8 @@ html_header("Submit");
 ?>
 
 <form action='pkgsubmit.php' method='post' enctype='multipart/form-data'>
-	<div> <input type='hidden' name='pkgsubmit' value='1' /> </div>
+	<div> <input type='hidden' name='pkgsubmit' value='1' />
+	<input type='hidden' name='token' value='<?php print htmlspecialchars($_COOKIE['AURSID']) ?>' /> </div>
 	<table border='0' cellspacing='5'>
 		<tr>
 			<td class='f4' align='right'><?php print __("Package Category"); ?>:</td>
diff --git a/web/html/tu.php b/web/html/tu.php
index 6e202c8..59cac1a 100644
--- a/web/html/tu.php
+++ b/web/html/tu.php
@@ -72,7 +72,7 @@ if ($atype == "Trusted User" OR $atype == "Developer") {
 				}
 
 				if ($canvote == 1) {
-					if (isset($_POST['doVote'])) {
+					if (isset($_POST['doVote']) && check_token()) {
 						if (isset($_POST['voteYes'])) {
 							$myvote = "Yes";
 						} else if (isset($_POST['voteNo'])) {