[newlib-cygwin/main] Cygwin: configure: disable High Entropy VA (64-bit ASLR) on AArch64

[Corinna Vinschen]

https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=c5a3641ba9173144ed40b85bea83c66bd649ee18

commit c5a3641ba9173144ed40b85bea83c66bd649ee18
Author:     Igor Podgainoi <Igor.Podgainoi@arm.com>
AuthorDate: Thu Feb 12 16:26:43 2026 +0000
Commit:     Corinna Vinschen <corinna@vinschen.de>
CommitDate: Thu Feb 12 21:11:10 2026 +0100

    Cygwin: configure: disable High Entropy VA (64-bit ASLR) on AArch64
    
    Currently Cygwin does not support the High Entropy Virtual Addressing
    feature, also known as IMAGE_DLL_CHARACTERISTICS_HIGH_ENTROPY_VA and
    64-bit Address Space Layout Randomization in Windows.
    
    Whereas on systems running on the x86_64 architecture this feature is
    already disabled by default in the toolchain during the build process,
    the AArch64 version of the toolchain leaves it enabled, even though it
    is not mandatory to use it on Windows on Arm. Only the normal ASLR flag
    IMAGE_DLLCHARACTERISTICS_DYNAMIC_BASE is mandatory, which this patch
    does not address.
    
    Therefore, this patch manually introduces the addition of High Entropy
    VA disabling flags into several places in various Makefile.am files.
    This should prevent memory overlap bugs on AArch64.
    
    Tests fixed on AArch64:
    winsup.api/ltp/fork06.exe
    winsup.api/ltp/fork07.exe
    winsup.api/ltp/fork11.exe
    
    Signed-off-by: Igor Podgainoi <igor.podgainoi@arm.com>

Diff:
---
 winsup/cygserver/Makefile.am | 2 +-
 winsup/cygwin/Makefile.am    | 2 +-
 winsup/testsuite/Makefile.am | 2 +-
 winsup/utils/Makefile.am     | 4 ++--
 4 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/winsup/cygserver/Makefile.am b/winsup/cygserver/Makefile.am
index efb578e53ece..9954ebe5daf0 100644
--- a/winsup/cygserver/Makefile.am
+++ b/winsup/cygserver/Makefile.am
@@ -38,7 +38,7 @@ cygserver_SOURCES = \
 
 cygserver_CXXFLAGS = $(cygserver_flags) -D__OUTSIDE_CYGWIN__
 cygserver_LDADD = -lntdll
-cygserver_LDFLAGS = -static -static-libgcc
+cygserver_LDFLAGS = -static -static-libgcc -Wl,--disable-high-entropy-va
 
 # Note: the objects in libcygserver are built without -D__OUTSIDE_CYGWIN__,
 # unlike cygserver.exe
diff --git a/winsup/cygwin/Makefile.am b/winsup/cygwin/Makefile.am
index 90a7332a8fbf..5f5fdc5ab0e2 100644
--- a/winsup/cygwin/Makefile.am
+++ b/winsup/cygwin/Makefile.am
@@ -620,7 +620,7 @@ $(NEW_DLL_NAME): $(LDSCRIPT) libdll.a $(VERSION_OFILES) $(LIBSERVER)\
 	$(AM_V_CXXLD)$(CXX) $(CXXFLAGS) \
 	-mno-use-libstdc-wrappers \
 	-Wl,--gc-sections -nostdlib -Wl,-T$(LDSCRIPT) \
-	-Wl,--dynamicbase -static \
+	-Wl,--dynamicbase -Wl,--disable-high-entropy-va -static \
 	$${SOURCE_DATE_EPOCH:+-Wl,--no-insert-timestamp} \
 	-Wl,--heap=0 -Wl,--out-implib,cygdll.a -shared -o $@ \
 	-e @DLL_ENTRY@ $(DEF_FILE) \
diff --git a/winsup/testsuite/Makefile.am b/winsup/testsuite/Makefile.am
index 0ff23d041897..529853849e2e 100644
--- a/winsup/testsuite/Makefile.am
+++ b/winsup/testsuite/Makefile.am
@@ -328,7 +328,7 @@ LDADD_FOR_TESTDLL = $(builddir)/../cygwin/libcygwin.a -lgcc -lkernel32 -luser32
 
 # flags for test executables
 AM_CPPFLAGS = -I$(srcdir)/libltp/include
-AM_LDFLAGS = $(LDFLAGS_FOR_TESTDLL)
+AM_LDFLAGS = $(LDFLAGS_FOR_TESTDLL) -Wl,--disable-high-entropy-va
 LDADD = $(builddir)/libltp.a $(builddir)/../cygwin/binmode.o $(LDADD_FOR_TESTDLL)
 
 # additional flags for specific test executables
diff --git a/winsup/utils/Makefile.am b/winsup/utils/Makefile.am
index 4a7936a6efdc..e44079a41d7f 100644
--- a/winsup/utils/Makefile.am
+++ b/winsup/utils/Makefile.am
@@ -73,14 +73,14 @@ tzmap.h:
 
 BUILT_SOURCES = tzmap.h
 
-AM_LDFLAGS = -static -Wl,--enable-auto-import
+AM_LDFLAGS = -static -Wl,--enable-auto-import -Wl,--disable-high-entropy-va
 LDADD = -lnetapi32
 
 cygpath_CXXFLAGS = -fno-threadsafe-statics $(AM_CXXFLAGS)
 cygpath_LDADD = $(LDADD) -luserenv -lntdll
 dumper_CXXFLAGS = -I$(top_srcdir)/../include $(AM_CXXFLAGS)
 dumper_LDADD = $(LDADD) -lpsapi -lntdll -lbfd @BFD_LIBS@
-dumper_LDFLAGS =
+dumper_LDFLAGS = -Wl,--disable-high-entropy-va
 ldd_LDADD = $(LDADD) -lpsapi -lntdll
 mount_CXXFLAGS = -DFSTAB_ONLY $(AM_CXXFLAGS)
 minidumper_LDADD = $(LDADD) -ldbghelp