[PATCH v9 0/1] MR8786: winebuild: Add flag to disable dynamicbase/aslr
Commit 518e394794160818ffe6826c874ff2f550c95bbb introduced new and important default behavior for PE binaries built using `winegcc`/`wineg++`/`winebuild`. * `/DYNAMICBASE` - Generates an executable image that can be randomly rebased at load time by using the address space layout randomization (ASLR) feature of Windows that was first available in Windows Vista. * `/HIGHENTROPYVA` - Randomized 64-bit virtual addresses make it more difficult for an attacker to guess the location of a particular memory region. ... however as identified in https://bugs.winehq.org/show_bug.cgi?id=58480, this new default behavior can severely impact applications that interact with binaries created for Windows XP and older. This is quite common for legacy audio plugins, such as VST2(TM) plugins. This MR keeps the new default "dynamicbase" and "highentropyva" flags by default, but mirrors the mingw/msys2 `--disable-dynamicbase` flag as explained here: https://www.msys2.org/news/#2021-01-31-aslr-enabled-by-default. MSVC also provides a similarly named flag [here](https://learn.microsoft.com/en-us/cpp/build/reference/dynamicbase). Downstream, the LMMS project has successfully deployed the mingw flag and the MSVC flag for our Windows builds. Our Linux builds use a custom wine-bridge and would benefit from the same. We've currently tested this MR downstream against a snapshot of master branch to passing results. Downstream PRs: * Linux: https://github.com/LMMS/lmms/pull/7987 * Windows: https://github.com/LMMS/lmms/pull/7976 -- v9: winebuild: Add flag to disable dynamicbase/aslr https://gitlab.winehq.org/wine/wine/-/merge_requests/8786
From: Tres Finocchiaro <tres.finocchiaro(a)gmail.com> --- tools/winebuild/main.c | 7 +++++++ tools/winebuild/winebuild.man.in | 4 ++++ 2 files changed, 11 insertions(+) diff --git a/tools/winebuild/main.c b/tools/winebuild/main.c index b38c70dc71e..8d407f18e6a 100644 --- a/tools/winebuild/main.c +++ b/tools/winebuild/main.c @@ -182,6 +182,7 @@ static const char usage_str[] = " --data-only Generate a data-only dll (i.e. without any executable code)\n" " -d, --delay-lib=LIB Import the specified library in delayed mode\n" " -D SYM Ignored for C flags compatibility\n" +" --disable-dynamicbase Disable 'ASLR' address space layout randomization (default: ASLR on)\n" " -e, --entry=FUNC Set the DLL entry point function (default: DllMain)\n" " -E, --export=FILE Export the symbols defined in the .spec or .def file\n" " --external-symbols Allow linking to external symbols\n" @@ -226,6 +227,7 @@ enum long_options_values { LONG_OPT_DLL = 1, LONG_OPT_DEF, + LONG_OPT_DISABLE_DYNAMICBASE, LONG_OPT_EXE, LONG_OPT_IMPLIB, LONG_OPT_BUILTIN, @@ -256,6 +258,7 @@ static const struct long_option long_options[] = /* mode options */ { "dll", 0, LONG_OPT_DLL }, { "def", 0, LONG_OPT_DEF }, + { "disable-dynamicbase", 0, LONG_OPT_DISABLE_DYNAMICBASE }, { "exe", 0, LONG_OPT_EXE }, { "implib", 0, LONG_OPT_IMPLIB }, { "staticlib", 0, LONG_OPT_STATICLIB }, @@ -436,6 +439,9 @@ static void option_callback( int optc, char *optarg ) case LONG_OPT_DEF: set_exec_mode( MODE_DEF ); break; + case LONG_OPT_DISABLE_DYNAMICBASE: + main_spec->dll_characteristics &= ~IMAGE_DLLCHARACTERISTICS_DYNAMIC_BASE; + break; case LONG_OPT_EXE: set_exec_mode( MODE_EXE ); if (!main_spec->subsystem) main_spec->subsystem = IMAGE_SUBSYSTEM_WINDOWS_GUI; @@ -598,6 +604,7 @@ int main(int argc, char **argv) else { spec->characteristics |= IMAGE_FILE_LARGE_ADDRESS_AWARE; + /* no-op if disable-dynamicbase is set */ spec->dll_characteristics |= IMAGE_DLLCHARACTERISTICS_HIGH_ENTROPY_VA; } diff --git a/tools/winebuild/winebuild.man.in b/tools/winebuild/winebuild.man.in index 73bcc836d12..25f17aff0bf 100644 --- a/tools/winebuild/winebuild.man.in +++ b/tools/winebuild/winebuild.man.in @@ -133,6 +133,10 @@ Specify a code generation option. Currently \fB\-fPIC\fR and \fB\-fasynchronous-unwind-tables\fR are supported. Other options are ignored for compatibility with the C compiler. .TP +.B \--disable-dynamicbase +Disable 'ASLR' address space layout randomization in executable image. +The default is 'ASLR' enabled. +.TP .B \--fake-module Create a fake PE module for a dll or exe, instead of the normal assembly or object file. The PE module contains the resources for the -- GitLab https://gitlab.winehq.org/wine/wine/-/merge_requests/8786
On Fri Aug 22 21:29:52 2025 +0000, Alexandre Julliard wrote:
Looks good, thanks. Could you please also update the man page? Sure, is this OK?
Preview using `man tools/winebuild/winebuild.man.in`: ```diff -f option Specify a code generation option. Currently -fPIC and -fasynchronous-unwind-tables are supported. Other options are ignored for compatibility with the C compiler. + --disable-dynamicbase + Disable 'ASLR' address space layout randomization in executable + image. The default is 'ASLR' enabled. + --fake-module Create a fake PE module for a dll or exe, instead of the normal assembly or object file. The PE module contains the resources for the module, but no executable code. ``` -- https://gitlab.winehq.org/wine/wine/-/merge_requests/8786#note_113682
On Fri Aug 22 23:05:51 2025 +0000, Tres Finocchiaro wrote:
Sure, is this OK? Preview using `man tools/winebuild/winebuild.man.in`: ```diff -f option Specify a code generation option. Currently -fPIC and -fasynchronous-unwind-tables are supported. Other options are ignored for compatibility with the C compiler. + --disable-dynamicbase + Disable 'ASLR' address space layout randomization in executable + image. The default is 'ASLR' enabled. + --fake-module Create a fake PE module for a dll or exe, instead of the normal assembly or object file. The PE module contains the resources for the module, but no executable code. ``` Sure, that's fine.
-- https://gitlab.winehq.org/wine/wine/-/merge_requests/8786#note_113719
participants (3)
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Alexandre Julliard (＠julliard) -
Tres Finocchiaro
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Tres Finocchiaro (＠tresf)