Add support for adding SSH public keys to profiles

Users can now add an SSH public key on the account edit page. This will
later be used to authenticate users via SSH.

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

1 files changed, 71 insertions, 7 deletions

diff --git a/web/lib/acctfuncs.inc.php b/web/lib/acctfuncs.inc.php
index 2d8dbafd..20ac081d 100644
--- a/web/lib/acctfuncs.inc.php
+++ b/web/lib/acctfuncs.inc.php
@@ -53,13 +53,14 @@ function html_format_pgp_fingerprint($fingerprint) {
  * @param string $L The language preference of the displayed user
  * @param string $I The IRC nickname of the displayed user
  * @param string $K The PGP key fingerprint of the displayed user
+ * @param string $PK The SSH public key of the displayed user
  * @param string $J The inactivity status of the displayed user
  * @param string $UID The user ID of the displayed user
  *
  * @return void
  */
-function display_account_form($A,$U="",$T="",$S="",
-		$E="",$P="",$C="",$R="",$L="",$I="",$K="",$J="", $UID=0) {
+function display_account_form($A,$U="",$T="",$S="",$E="",$P="",$C="",$R="",
+		$L="",$I="",$K="",$PK="",$J="", $UID=0) {
 	global $SUPPORTED_LANGS;
 
 	include("account_edit_form.php");
@@ -82,13 +83,14 @@ function display_account_form($A,$U="",$T="",$S="",
  * @param string $L The language preference of the user
  * @param string $I The IRC nickname of the user
  * @param string $K The PGP fingerprint of the user
+ * @param string $PK The SSH public key of the user
  * @param string $J The inactivity status of the user
  * @param string $UID The user ID of the modified account
  *
  * @return string|void Return void if successful, otherwise return error
  */
-function process_account_form($TYPE,$A,$U="",$T="",$S="",$E="",
-			$P="",$C="",$R="",$L="",$I="",$K="",$J="",$UID=0) {
+function process_account_form($TYPE,$A,$U="",$T="",$S="",$E="",$P="",$C="",
+		$R="",$L="",$I="",$K="",$PK="",$J="",$UID=0) {
 	global $SUPPORTED_LANGS;
 
 	$error = '';
@@ -146,6 +148,15 @@ function process_account_form($TYPE,$A,$U="",$T="",$S="",$E="",
 		$error = __("The PGP key fingerprint is invalid.");
 	}
 
+	if (!$error && !empty($PK)) {
+		if (valid_ssh_pubkey($PK)) {
+			$tokens = explode(" ", $PK);
+			$PK = $tokens[0] . " " . $tokens[1];
+		} else {
+			$error = __("The SSH public key is invalid.");
+		}
+	}
+
 	if (isset($_COOKIE['AURSID'])) {
 		$atype = account_from_sid($_COOKIE['AURSID']);
 		if (($atype == "User" && $T > 1) || ($atype == "Trusted User" && $T > 2)) {
@@ -192,11 +203,29 @@ function process_account_form($TYPE,$A,$U="",$T="",$S="",$E="",
 					"<strong>", htmlspecialchars($E,ENT_QUOTES), "</strong>");
 		}
 	}
+	if (!$error) {
+		/*
+		 * Check whether the SSH public key is available.
+		 * TODO: Fix race condition.
+		 */
+		$q = "SELECT COUNT(*) FROM Users ";
+		$q.= "WHERE SSHPubKey = " . $dbh->quote($PK);
+		if ($TYPE == "edit") {
+			$q.= " AND ID != " . intval($UID);
+		}
+		$result = $dbh->query($q);
+		$row = $result->fetch(PDO::FETCH_NUM);
+
+		if ($row[0]) {
+			$error = __("The SSH public key, %s%s%s, is already in use.",
+					"<strong>", htmlspecialchars($PK, ENT_QUOTES), "</strong>");
+		}
+	}
 
 	if ($error) {
 		print "<ul class='errorlist'><li>".$error."</li></ul>\n";
 		display_account_form($A, $U, $T, $S, $E, "", "",
-				$R, $L, $I, $K, $J, $UID);
+				$R, $L, $I, $K, $PK, $J, $UID);
 		return;
 	}
 
@@ -218,11 +247,13 @@ function process_account_form($TYPE,$A,$U="",$T="",$S="",$E="",
 		$L = $dbh->quote($L);
 		$I = $dbh->quote($I);
 		$K = $dbh->quote(str_replace(" ", "", $K));
+		$PK = $dbh->quote($PK);
 		$q = "INSERT INTO Users (AccountTypeID, Suspended, ";
 		$q.= "InactivityTS, Username, Email, Passwd, Salt, ";
-		$q.= "RealName, LangPreference, IRCNick, PGPKey) ";
+		$q.= "RealName, LangPreference, IRCNick, PGPKey, ";
+		$q.= "SSHPubKey) ";
 		$q.= "VALUES (1, 0, 0, $U, $E, $P, $salt, $R, $L, ";
-		$q.= "$I, $K)";
+		$q.= "$I, $K, $PK)";
 		$result = $dbh->exec($q);
 		if (!$result) {
 			print __("Error trying to create account, %s%s%s.",
@@ -290,6 +321,7 @@ function process_account_form($TYPE,$A,$U="",$T="",$S="",$E="",
 		$q.= ", LangPreference = " . $dbh->quote($L);
 		$q.= ", IRCNick = " . $dbh->quote($I);
 		$q.= ", PGPKey = " . $dbh->quote(str_replace(" ", "", $K));
+		$q.= ", SSHPubKey = " . $dbh->quote($PK);
 		$q.= ", InactivityTS = " . $inactivity_ts;
 		$q.= " WHERE ID = ".intval($UID);
 		$result = $dbh->exec($q);
@@ -800,6 +832,38 @@ function valid_pgp_fingerprint($fingerprint) {
 }
 
 /**
+ * Determine if the SSH public key is valid
+ *
+ * @param string $pubkey SSH public key to check
+ *
+ * @return bool True if the SSH public key is valid, otherwise false
+ */
+function valid_ssh_pubkey($pubkey) {
+	$valid_prefixes = array(
+		"ssh-rsa", "ssh-dss", "ecdsa-sha2-nistp256",
+		"ecdsa-sha2-nistp384", "ecdsa-sha2-nistp521", "ssh-ed25519"
+	);
+
+	$has_valid_prefix = false;
+	foreach ($valid_prefixes as $prefix) {
+		if (strpos($pubkey, $prefix . " ") === 0) {
+			$has_valid_prefix = true;
+			break;
+		}
+	}
+	if (!$has_valid_prefix) {
+		return false;
+	}
+
+	$tokens = explode(" ", $pubkey);
+	if (empty($tokens[1])) {
+		return false;
+	}
+
+	return (base64_encode(base64_decode($tokens[1], true)) == $tokens[1]);
+}
+
+/**
  * Determine if the user account has been suspended
  *
  * @param string $id The ID of user to check if suspended