Kobo/WifiDialog: use PBKDF2-SHA1 passwords

On older Kobos like the Kobo Mini, wpa_supplicant accepts ASCII
passwords, newer models require a PBKDF2-SHA1 digest.  This is
implemented using libcrypto (OpenSSL).

NEWS.txt

@@ -9,6 +9,7 @@ Version 7.23 - not yet released
   - fix broken button text background
   - add OTG support (serial, sound, net) for Clara HD
   - fix "Network failure" in Wifi dialog
+  - support Wifi on Clara HD
 
 Version 7.22 - 2022/01/14
 * user interface

build/kobo.mk

@@ -1,3 +1,5 @@
+$(eval $(call pkg-config-library,LIBCRYPTO,libcrypto))
+
 KOBO_MENU_SOURCES = \
 	$(SRC)/Version.cpp \
 	$(SRC)/Asset.cpp \
@@ -37,7 +39,7 @@ KOBO_MENU_SOURCES = \
 	$(SRC)/Kobo/WifiDialog.cpp \
 	$(SRC)/Kobo/FakeSymbols.cpp \
 	$(SRC)/Kobo/KoboMenu.cpp
-KOBO_MENU_DEPENDS = WIDGET FORM SCREEN EVENT RESOURCE ASYNC LIBNET OS IO THREAD MATH UTIL
+KOBO_MENU_DEPENDS = WIDGET FORM SCREEN EVENT RESOURCE ASYNC LIBNET OS IO THREAD MATH UTIL LIBCRYPTO
 KOBO_MENU_STRIP = y
 
 $(eval $(call link-program,KoboMenu,KOBO_MENU))

build/libutil.mk

@@ -13,6 +13,7 @@ UTIL_SOURCES = \
 	$(UTIL_SRC_DIR)/TruncateString.cpp \
 	$(UTIL_SRC_DIR)/EscapeBackslash.cpp \
 	$(UTIL_SRC_DIR)/ExtractParameters.cpp \
+	$(UTIL_SRC_DIR)/HexFormat.cxx \
 	$(UTIL_SRC_DIR)/ConvertString.cpp \
 	$(UTIL_SRC_DIR)/StaticString.cxx \
 	$(UTIL_SRC_DIR)/StringBuilder.cxx \

doc/build.rst

@@ -133,6 +133,7 @@ The following command installs these on Debian::
       libtiff5-dev libgeotiff-dev \
       libc-ares-dev \
       libcurl4-openssl-dev \
+      libssl-dev \
       libc-ares-dev \
       liblua5.4-dev \
       libxml-parser-perl \

ide/provisioning/install-debian-packages.sh

@@ -38,6 +38,7 @@ apt-get install ${APTOPTS[*]} make g++ \
   libfreetype6-dev \
   libpng-dev libjpeg-dev \
   libtiff5-dev libgeotiff-dev \
+  libssl-dev \
   libcurl4-openssl-dev \
   libc-ares-dev \
   liblua5.4-dev \

src/Kobo/WPASupplicant.hpp

@@ -126,7 +126,7 @@ class WPASupplicant {
   }
 
   void SetNetworkPSK(unsigned id, const char *psk) {
-    SetNetworkString(id, "psk", psk);
+    SetNetworkID(id, "psk", psk);
   }
 
   void SelectNetwork(unsigned id);

src/Kobo/WifiDialog.cpp

@@ -36,6 +36,13 @@ Copyright_License {
 #include "WPASupplicant.hpp"
 #include "net/IPv4Address.hxx"
 #include "ui/event/PeriodicTimer.hpp"
+#include "util/HexFormat.hxx"
+
+/* workaround because OpenSSL has a typedef called "UI", which clashes
+   with our "UI" namespace */
+#define UI OPENSSL_UI
+#include <openssl/evp.h> // for PKCS5_PBKDF2_HMAC_SHA1()
+#undef UI
 
 class WifiListWidget final
   : public ListWidget {
@@ -216,8 +223,16 @@ WifiConnect(enum WifiSecurity security, WPASupplicant &wpa_supplicant, const cha
   wpa_supplicant.SetNetworkSSID(id, ssid);
 
   if (security == WPA_SECURITY) {
+    std::array<unsigned char, 32> pmk;
+    PKCS5_PBKDF2_HMAC_SHA1(psk, strlen(psk),
+                           (const unsigned char *)ssid, strlen(ssid),
+                           4096,
+                           pmk.size(), pmk.data());
+
+    std::array<char, sizeof(pmk) * 2 + 1> hex;
+    *HexFormat(hex.data(), {pmk.data(), pmk.size()}) = 0;
 
-    wpa_supplicant.SetNetworkPSK(id, psk);
+    wpa_supplicant.SetNetworkPSK(id, hex.data());
   } else if (security == WEP_SECURITY) {
     wpa_supplicant.SetNetworkID(id, "key_mgmt", "NONE");
 

src/util/HexFormat.cxx

@@ -0,0 +1,43 @@
+/*
+ * Copyright (C) 2018 Max Kellermann <[email protected]>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * - Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the
+ * distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
+ * FOUNDATION OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "HexFormat.hxx"
+
+#include <stdio.h>
+
+char *
+HexFormat(char *dest, ConstBuffer<uint8_t> src) noexcept
+{
+	for (auto i : src) {
+		sprintf(dest, "%02x", i);
+		dest += 2;
+	}
+
+	return dest;
+}

src/util/HexFormat.hxx

@@ -0,0 +1,64 @@
+/*
+ * Copyright (C) 2018 Max Kellermann <[email protected]>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * - Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the
+ * distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
+ * FOUNDATION OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef HEX_FORMAT_HXX
+#define HEX_FORMAT_HXX
+
+#include "ConstBuffer.hxx"
+#include "StringBuffer.hxx"
+
+#include <cstddef>
+#include <cstdint>
+
+/**
+ * Format the given byte sequence into a null-terminated hexadecimal
+ * string.
+ *
+ * @param dest the destination buffer; must be large enough to hold
+ * all hex digits plus the null terminator
+ * @return a pointer to the generated null terminator
+ */
+char *
+HexFormat(char *dest, ConstBuffer<uint8_t> src) noexcept;
+
+/**
+ * Like HexFormat(), but return a #StringBuffer with exactly the
+ * required size.
+ */
+template<size_t size>
+[[gnu::pure]]
+auto
+HexFormatBuffer(const uint8_t *src) noexcept
+{
+	StringBuffer<size * 2 + 1> dest;
+	HexFormat(dest.data(), {src, size});
+	return dest;
+}
+
+#endif