From d8d1cf2e35d674502bfa2512ded21f7f9b421318 Mon Sep 17 00:00:00 2001
From: Sebastian Lackner <sebastian@fds-team.de>
Date: Sat, 16 Apr 2016 22:45:16 +0200
Subject: [PATCH] Added patch to trigger stack overflow exception earlier on
 x86_64.

---
 ...ack-overflow-exception-earlier-on-x8.patch | 29 +++++++++++++++++++
 patches/ntdll-Stack_Overflow/definition       |  1 +
 patches/patchinstall.sh                       | 16 ++++++++++
 3 files changed, 46 insertions(+)
 create mode 100644 patches/ntdll-Stack_Overflow/0001-ntdll-Trigger-stack-overflow-exception-earlier-on-x8.patch
 create mode 100644 patches/ntdll-Stack_Overflow/definition

diff --git a/patches/ntdll-Stack_Overflow/0001-ntdll-Trigger-stack-overflow-exception-earlier-on-x8.patch b/patches/ntdll-Stack_Overflow/0001-ntdll-Trigger-stack-overflow-exception-earlier-on-x8.patch
new file mode 100644
index 00000000..7ae36d89
--- /dev/null
+++ b/patches/ntdll-Stack_Overflow/0001-ntdll-Trigger-stack-overflow-exception-earlier-on-x8.patch
@@ -0,0 +1,29 @@
+From a679044828d05cd420b1fb4a0dc43fb49da8d665 Mon Sep 17 00:00:00 2001
+From: Sebastian Lackner <sebastian@fds-team.de>
+Date: Sat, 16 Apr 2016 22:29:12 +0200
+Subject: ntdll: Trigger stack overflow exception earlier on x86_64.
+
+The Cygwin/MSYS2 exception handler seems to exceed one page,
+which breaks handling of stack faults.
+---
+ dlls/ntdll/signal_x86_64.c | 3 ++-
+ 1 file changed, 2 insertions(+), 1 deletion(-)
+
+diff --git a/dlls/ntdll/signal_x86_64.c b/dlls/ntdll/signal_x86_64.c
+index 94157bb..81d1758 100644
+--- a/dlls/ntdll/signal_x86_64.c
++++ b/dlls/ntdll/signal_x86_64.c
+@@ -2600,8 +2600,9 @@ static void segv_handler( int signal, siginfo_t *siginfo, void *sigcontext )
+         virtual_handle_stack_fault( siginfo->si_addr ))
+     {
+         /* check if this was the last guard page */
+-        if ((char *)siginfo->si_addr < (char *)NtCurrentTeb()->DeallocationStack + 2*4096)
++        if ((char *)siginfo->si_addr < (char *)NtCurrentTeb()->DeallocationStack + 3*4096)
+         {
++            virtual_handle_stack_fault( (char *)siginfo->si_addr - 4096 );
+             rec = setup_exception( sigcontext, raise_segv_exception );
+             rec->ExceptionCode = EXCEPTION_STACK_OVERFLOW;
+         }
+-- 
+2.7.1
+
diff --git a/patches/ntdll-Stack_Overflow/definition b/patches/ntdll-Stack_Overflow/definition
new file mode 100644
index 00000000..0099150c
--- /dev/null
+++ b/patches/ntdll-Stack_Overflow/definition
@@ -0,0 +1 @@
+Fixes: Trigger stack overflow exception earlier on x86_64
diff --git a/patches/patchinstall.sh b/patches/patchinstall.sh
index 07413ef5..cc90a780 100755
--- a/patches/patchinstall.sh
+++ b/patches/patchinstall.sh
@@ -224,6 +224,7 @@ patch_enable_all ()
 	enable_ntdll_RtlIpStringToAddress_Tests="$1"
 	enable_ntdll_RtlQueryPackageIdentity="$1"
 	enable_ntdll_Serial_Port_Detection="$1"
+	enable_ntdll_Stack_Overflow="$1"
 	enable_ntdll_Status_Mapping="$1"
 	enable_ntdll_Syscall_Wrappers="$1"
 	enable_ntdll_SystemInterruptInformation="$1"
@@ -846,6 +847,9 @@ patch_enable ()
 		ntdll-Serial_Port_Detection)
 			enable_ntdll_Serial_Port_Detection="$2"
 			;;
+		ntdll-Stack_Overflow)
+			enable_ntdll_Stack_Overflow="$2"
+			;;
 		ntdll-Status_Mapping)
 			enable_ntdll_Status_Mapping="$2"
 			;;
@@ -5032,6 +5036,18 @@ if test "$enable_ntdll_Serial_Port_Detection" -eq 1; then
 	) >> "$patchlist"
 fi
 
+# Patchset ntdll-Stack_Overflow
+# |
+# | Modified files:
+# |   *	dlls/ntdll/signal_x86_64.c
+# |
+if test "$enable_ntdll_Stack_Overflow" -eq 1; then
+	patch_apply ntdll-Stack_Overflow/0001-ntdll-Trigger-stack-overflow-exception-earlier-on-x8.patch
+	(
+		echo '+    { "Sebastian Lackner", "ntdll: Trigger stack overflow exception earlier on x86_64.", 1 },';
+	) >> "$patchlist"
+fi
+
 # Patchset ntdll-Status_Mapping
 # |
 # | Modified files: