Patch eap.o memory leak

WiFi Enterprise option can leak up to 3 allocations per connect/disconnect
cycle: anonymous Identity, password, and some unidentified allocation.

This solution patches eap.o from libwpa2 to call a special 2 part
wrapper instead of vPortFree for cleanup.

cores/esp8266/coredecls.h

@@ -21,6 +21,7 @@ void esp_schedule();
 void esp_yield();
 void tune_timeshift64 (uint64_t now_us);
 void disable_extra4k_at_link_time (void) __attribute__((noinline));
+void enable_wifi_enterprise_patch(void) __attribute__((noinline));
 bool sntp_set_timezone_in_seconds(int32_t timezone);
 void __disableWiFiAtBootTime (void) __attribute__((noinline));
 void __real_system_restart_local() __attribute__((noreturn));

cores/esp8266/heap.cpp

@@ -5,7 +5,13 @@
 
 #include <stdlib.h>
 #include "umm_malloc/umm_malloc.h"
-extern "C" size_t umm_umul_sat(const size_t a, const size_t b);;
+extern "C" size_t umm_umul_sat(const size_t a, const size_t b);
+
+// z2EapFree: See wpa2_eap_patch.cpp for details
+extern "C" void z2EapFree(void *ptr, const char* file, int line) __attribute__((weak, alias("vPortFree"), nothrow));
+// I don't understand all the compiler noise around this alias.
+// Adding "__attribute__ ((nothrow))" seems to resolve the issue.
+// This may be relevant: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81824 
 
 // Need FORCE_ALWAYS_INLINE to put HeapSelect class constructor/deconstructor in IRAM
 #define FORCE_ALWAYS_INLINE_HEAP_SELECT

cores/esp8266/wpa2_eap_patch.cpp

@@ -0,0 +1,118 @@
+/*
+ * To implement this patch, the SDK module `eap.o` from archive `libwpa2.a` must
+ * be patched to call `z2EapFree` instead of `vPortFree`. This limits extending
+ * the execution time of vPortFree to that module only. Not impacting other
+ * modules.
+ *
+ */
+
+#include <string.h>
+#include <ets_sys.h>
+#include <pgmspace.h>
+#include "coredecls.h"
+#if 0
+#include "esp8266_undocumented.h"
+#define DEBUG_PRINTF ets_uart_printf
+#else
+#define DEBUG_PRINTF(...)
+#endif
+
+extern "C" {
+
+// extern "C" void z2EapFree(void *ptr, const char* file, int line) __attribute__((weak, alias("vPortFree")));
+
+/*
+ * Limited 2-part wrapper for vPortFree calls made in SDK module `eap.o` from
+ * archive `libwpa2.a`.
+ *
+ * vPortFree calls from eap.o are monitored for calls from line 799. This is
+ * the location of the memory leak. At entry register a12 contains the structure
+ * address which has the addresses of the allocations that will be leaked.
+ *
+ * Part 1 of this wrapper, z2EapFree, appends the value of register a12 as a
+ * 4th argument to part2 of this wrapper, patch_wpa2_eap_vPortFree_a12(). Which
+ * in turn checks and frees the additional allocations, that would have been
+ * lost.
+ *
+ * extern "C" z2EapFree(void*);
+ */
+
+/*
+ * Part 1 of Limited vPortFree Wrapper
+ */
+asm(
+    // ".section     .iram.text.z2EapFree,\"ax\",@progbits\n\t"
+    ".section     .text.z2EapFree,\"ax\",@progbits\n\t"
+    ".literal_position\n\t"
+    ".literal     .patch_wpa2_eap_vPortFree_a12, patch_wpa2_eap_vPortFree_a12\n\t"
+    ".align       4\n\t"
+    ".global      z2EapFree\n\t"
+    ".type        z2EapFree, @function\n\t"
+    "\n"
+"z2EapFree:\n\t"
+    "addi         a1,     a1,     -16\n\t"
+    "s32i         a0,     a1,     0\n\t"
+    "mov          a5,     a12\n\t"
+    "l32r         a0,     .patch_wpa2_eap_vPortFree_a12\n\t"
+    "callx0       a0\n\t"
+    "l32i         a0,     a1,     0\n\t"
+    "addi         a1,     a1,     16\n\t"
+    "ret\n\t"
+    ".size z2EapFree, .-z2EapFree\n\t"
+);
+
+/*
+ * While some insight can be gained from the ESP32 repo for this structure.
+ * It does not match exactly. This alternate structure focuses on correct offset
+ * rather than trying to exactly reconstruct the original labels.
+ */
+struct StateMachine { // size 200 bytes
+    void* befoeConfig[16];
+    void* config[26];
+    // 0  - mov a2, a12, 64  // username / Identity
+    // 1  - mov a2, a12, 68
+    // 2  - mov a2, a12, 72  // anonymous Identity
+    // 3  - mov a2, a12, 76
+    // 4  - mov a2, a12, 80  // password
+    // 21 - mov a2, a12, 148 // ??
+    void* afterConfig[8];
+};
+
+/*
+ * Part 2 of Limited vPortFree Wrapper
+ *
+ * Presently, all SDKs have the same memory leaks in the same module at the
+ * same line.
+ */
+void patch_wpa2_eap_vPortFree_a12(void *ptr, const char* file, int line, void* a12) {
+    if (799 == line) {
+        struct StateMachine* sm = (struct StateMachine*)a12;
+        if (ptr == sm->config[0]) {
+            // Fix leaky frunction - eap.o only frees one out of 4 config items
+            // finish the other 3 first
+            vPortFree(sm->config[2], file, line);
+            vPortFree(sm->config[4], file, line);
+            vPortFree(sm->config[21], file, line);
+            // ptr is sm->config[0], let fall through handle it
+        }
+        DEBUG_PRINTF("\nz2EapFree/vPortFree patch working\n");
+    }
+    vPortFree(ptr, file, line);
+}
+
+};
+
+/*
+ * This will minimize code space for non-wifi enterprise sketches which do not
+ * need the patch and disable_extra4k_at_link_time().
+ */
+void enable_wifi_enterprise_patch(void) {
+    /*
+     * Calling this from setup or anywhere ensures that the patch code is
+     * included in the build.
+     *
+     * Also, WiFi Enterprise uses a lot of system stack space and may crash
+     * unless we:
+     */
+    disable_extra4k_at_link_time();
+}

tools/sdk/lib/eval_fix_sdks.sh

@@ -0,0 +1,97 @@
+#!/bin/bash
+# set -e
+
+add_path_ifexist() {
+  if [[ -d $1 ]]; then
+		export PATH=$( realpath $1 ):$PATH
+		return 0
+	fi
+	return 1
+}
+
+if ! which xtensa-lx106-elf-ar | grep "tools/xtensa-lx106-elf/bin" >>/dev/null; then
+		add_path_ifexist "../../../xtensa-lx106-elf/bin" || add_path_ifexist "../../xtensa-lx106-elf/bin"
+fi
+
+
+list_sdks() {
+  cat <<EOF
+NONOSDK22x_190313
+NONOSDK22x_190703
+NONOSDK22x_191024
+NONOSDK22x_191105
+NONOSDK22x_191122
+NONOSDK221
+NONOSDK3V0
+EOF
+}
+
+remove_ifexist() {
+  [[ -f $1 ]] && rm $1
+}
+
+cleanup() {
+  remove_ifexist old.txt
+  remove_ifexist old2.txt
+  remove_ifexist new.txt
+  for sdk in `list_sdks`; do
+    remove_ifexist $sdk/eap/o
+  done
+}
+
+unasm() {
+  xtensa-lx106-elf-objdump -d $*
+}
+
+analyze() {
+  cleanup
+
+  for sdk in `list_sdks`; do
+    pushd $sdk
+    xtensa-lx106-elf-ar x libwpa2.a eap.o
+    popd
+  done
+  echo ""
+
+  find . -name eap.o -exec md5sum {} \; | sort
+  echo ""
+
+  unset prev_sdk
+  for sdk in `list_sdks`; do
+    unasm -j ".text.eap_peer_config_deinit" ${sdk}/eap.o >new.txt
+    if [[ -f old.txt ]]; then
+      echo "eap_peer_config_deinit: diff $prev_sdk $sdk"
+      diff old.txt new.txt
+      echo ""
+    fi
+    mv new.txt old.txt
+    prev_sdk=${sdk}
+  done
+
+  unset prev_sdk
+  for sdk in `list_sdks`; do
+    unasm -j ".text.wpa2_sm_rx_eapol" ${sdk}/eap.o >new.txt
+    if [[ -f old2.txt ]]; then
+      echo "wpa2_sm_rx_eapol: diff $prev_sdk $sdk"
+      diff old2.txt new.txt
+      echo ""
+    fi
+    mv new.txt old2.txt
+    prev_sdk=${sdk}
+  done
+
+  cleanup
+}
+
+
+patch_all() {
+  for sdk in `list_sdks`; do
+    pushd $sdk
+    ../fix_sdk_libs.sh
+    popd
+  done
+}
+
+# analyze
+patch_all
+exit 0

tools/sdk/lib/fix_sdk_libs.sh

@@ -1,36 +1,98 @@
 #!/bin/bash
 set -e
 
-export PATH=../../xtensa-lx106-elf/bin:$PATH
+add_path_ifexist() {
+  if [[ -d $1 ]]; then
+		export PATH=$( realpath $1 ):$PATH
+		return 0
+	fi
+	return 1
+}
+
+if ! which xtensa-lx106-elf-ar | grep "tools/xtensa-lx106-elf/bin" >>/dev/null; then
+		add_path_ifexist "../../../xtensa-lx106-elf/bin" || add_path_ifexist "../../xtensa-lx106-elf/bin"
+fi
+WORK_SPACE=${PWD}
+
 VERSION=$(basename ${PWD})
 
 addSymbol_system_func1() {
-	ADDRESS=$1
-	xtensa-lx106-elf-objcopy --add-symbol system_func1=.irom0.text:${ADDRESS},function,global user_interface.o
+	if ! xtensa-lx106-elf-nm  user_interface.o | grep -q " T system_func1"; then # Don't add symbol if it already exists
+		ADDRESS=$1
+		xtensa-lx106-elf-objcopy --add-symbol system_func1=.irom0.text:${ADDRESS},function,global user_interface.o
+	fi
 }
 
+patchFile() {
+	FILE=$1
+	ADDRESS=$2 # DO NOT PASS AS HEX!
+	LENGTH=$3 # DO NOT PASS AS HEX!
+	EXPECTED=$4
+	REPLACEWITH=$5
+	if [[ "$(dd if=$FILE bs=1 count=$LENGTH skip=$ADDRESS status=none | base64 -w0)" = "$EXPECTED" ]]; then
+		echo "Patching  $VERSION $1 ..."
+		echo $5 | base64 -d | dd of=$FILE bs=1 count=$LENGTH seek=$ADDRESS conv=notrunc
+	elif ! [[ "$(dd if=$FILE bs=1 count=$LENGTH skip=$ADDRESS status=none | base64 -w0)" = "$REPLACEWITH" ]]; then
+		echo "PATCH FAILED!"
+		echo "dd if=$FILE bs=1 count=$LENGTH skip=$ADDRESS status=none | base64 -w0"
+		dd if=$FILE bs=1 count=$LENGTH skip=$ADDRESS status=none | hexdump -C
+		dd if=$FILE bs=1 count=$LENGTH skip=$ADDRESS status=none | base64 -w0
+		echo ""
+		exit 0
+	fi
+}
+
+# # xtensa-lx106-elf-ar x libwpa2.a eap.o
+if [[ "--shell" == "$1" ]]; then
+	# need to poke around a bit
+	bash --rcfile <(echo '. ~/.bashrc; cd ${WORK_SPACE}')
+	exit 0
+fi
+
+if [[ ! -f libmain.a ]]; then
+  echo -e "\n\n*** Archive libmain.a is missing ***\n\n"
+  exit 1
+fi
 
 # Remove mem_manager.o from libmain.a to use custom heap implementation,
 # and time.o to fix redefinition of time-related functions:
 xtensa-lx106-elf-ar d libmain.a mem_manager.o
 xtensa-lx106-elf-ar d libmain.a time.o
 
+# Patch WPA2-Enterprise double-free
+xtensa-lx106-elf-ar x libwpa2.a eap.o
+eapcs=$(sha256sum eap.o | awk '{print $1}')
+
 # Rename `hostname` and `default_hostname` symbols:
 xtensa-lx106-elf-ar x libmain.a eagle_lwip_if.o user_interface.o
-xtensa-lx106-elf-objcopy --redefine-sym hostname=wifi_station_hostname user_interface.o 
-xtensa-lx106-elf-objcopy --redefine-sym hostname=wifi_station_hostname eagle_lwip_if.o 
-xtensa-lx106-elf-objcopy --redefine-sym default_hostname=wifi_station_default_hostname user_interface.o 
-xtensa-lx106-elf-objcopy --redefine-sym default_hostname=wifi_station_default_hostname eagle_lwip_if.o 
+lwipcs=$(sha256sum eagle_lwip_if.o | awk '{print $1}')
+uics=$(sha256sum user_interface.o | awk '{print $1}')
+xtensa-lx106-elf-objcopy --redefine-sym hostname=wifi_station_hostname user_interface.o
+xtensa-lx106-elf-objcopy --redefine-sym hostname=wifi_station_hostname eagle_lwip_if.o
+xtensa-lx106-elf-objcopy --redefine-sym default_hostname=wifi_station_default_hostname user_interface.o
+xtensa-lx106-elf-objcopy --redefine-sym default_hostname=wifi_station_default_hostname eagle_lwip_if.o
+
 
 if [[ ${VERSION} == "NONOSDK221" ]]; then
 	addSymbol_system_func1 "0x60"
+	patchFile "eap.o" "3055" "2" "wAA=" "8CA=" # WPA2-Enterprise patch which replaces a double-free with nop, see #8082
+	patchFile "eap.o" "26352" "9" "dlBvcnRGcmVl" "ejJFYXBGcmVl"   # special vPortFree to recover leaked memory
 elif [[ ${VERSION} == "NONOSDK22x"* ]]; then
 	addSymbol_system_func1 "0x54"
+	patchFile "eap.o" "3059" "2" "wAA=" "8CA=" # WPA2-Enterprise patch which replaces a double-free with nop, see #8082
+	patchFile "eap.o" "26356" "9" "dlBvcnRGcmVl" "ejJFYXBGcmVl"   # special vPortFree to recover leaked memory
 elif [[ ${VERSION} == "NONOSDK3"* ]]; then
 	addSymbol_system_func1 "0x60"
+	patchFile "eap.o" "3059" "2" "wAA=" "8CA=" # WPA2-Enterprise patch which replaces a double-free with nop, see #8082
+	patchFile "eap.o" "26356" "9" "dlBvcnRGcmVl" "ejJFYXBGcmVl"   # special vPortFree to recover leaked memory
 else
 	echo "WARN: Unknown address for system_func1() called by system_restart_local()"
 fi
 
-xtensa-lx106-elf-ar r libmain.a eagle_lwip_if.o user_interface.o 
-rm -f eagle_lwip_if.o user_interface.o
+if [[ $(sha256sum eap.o | awk '{print $1}') != $eapcs ]]; then
+	xtensa-lx106-elf-ar r libwpa2.a eap.o
+fi
+if [[ $(sha256sum user_interface.o | awk '{print $1}') != $uics || $(sha256sum eagle_lwip_if.o | awk '{print $1}') != $lwipcs ]]; then
+	xtensa-lx106-elf-ar r libmain.a eagle_lwip_if.o user_interface.o
+fi
+rm -f eagle_lwip_if.o user_interface.o eap.o