[PATCH v4 0/3] MR8786: Draft: 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 -- v4: Revert HIGHENTROPYVA flag https://gitlab.winehq.org/wine/wine/-/merge_requests/8786
From: Tres Finocchiaro <tres.finocchiaro(a)gmail.com> --- tools/winebuild/main.c | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-) diff --git a/tools/winebuild/main.c b/tools/winebuild/main.c index b38c70dc71e..8683b5874de 100644 --- a/tools/winebuild/main.c +++ b/tools/winebuild/main.c @@ -36,6 +36,7 @@ int UsePIC = 0; int nb_errors = 0; int display_warnings = 0; +int disable_dynamicbase = 0; int native_arch = -1; int kill_at = 0; int verbose = 0; @@ -182,6 +183,7 @@ 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 +228,7 @@ 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 +259,7 @@ 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 +440,9 @@ static void option_callback( int optc, char *optarg ) case LONG_OPT_DEF: set_exec_mode( MODE_DEF ); break; + case LONG_OPT_DISABLE_DYNAMICBASE: + disable_dynamicbase = 1; + break; case LONG_OPT_EXE: set_exec_mode( MODE_EXE ); if (!main_spec->subsystem) main_spec->subsystem = IMAGE_SUBSYSTEM_WINDOWS_GUI; @@ -598,7 +605,13 @@ int main(int argc, char **argv) else { spec->characteristics |= IMAGE_FILE_LARGE_ADDRESS_AWARE; - spec->dll_characteristics |= IMAGE_DLLCHARACTERISTICS_HIGH_ENTROPY_VA; + if (!disable_dynamicbase) { + spec->dll_characteristics |= IMAGE_DLLCHARACTERISTICS_HIGH_ENTROPY_VA; + } + } + + if (disable_dynamicbase) { + spec->dll_characteristics &= ~IMAGE_DLLCHARACTERISTICS_DYNAMIC_BASE; } check_target(); -- GitLab https://gitlab.winehq.org/wine/wine/-/merge_requests/8786
From: Tres Finocchiaro <tres.finocchiaro(a)gmail.com> --- tools/winebuild/main.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/tools/winebuild/main.c b/tools/winebuild/main.c index 8683b5874de..5f161dae529 100644 --- a/tools/winebuild/main.c +++ b/tools/winebuild/main.c @@ -37,6 +37,7 @@ int UsePIC = 0; int nb_errors = 0; int display_warnings = 0; int disable_dynamicbase = 0; +int disable_high_entropy_va = 0; int native_arch = -1; int kill_at = 0; int verbose = 0; @@ -184,6 +185,7 @@ static const char usage_str[] = " -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" +" --disable-high-entropy-va Disable high-entropy 64-bit 'ASLR' (default: high-entropy 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" @@ -229,6 +231,7 @@ enum long_options_values LONG_OPT_DLL = 1, LONG_OPT_DEF, LONG_OPT_DISABLE_DYNAMICBASE, + LONG_OPT_DISABLE_HIGH_ENTROPY_VA, LONG_OPT_EXE, LONG_OPT_IMPLIB, LONG_OPT_BUILTIN, @@ -260,6 +263,7 @@ static const struct long_option long_options[] = { "dll", 0, LONG_OPT_DLL }, { "def", 0, LONG_OPT_DEF }, { "disable-dynamicbase", 0, LONG_OPT_DISABLE_DYNAMICBASE }, + { "disable-high-entropy-va", 0, LONG_OPT_DISABLE_HIGH_ENTROPY_VA }, { "exe", 0, LONG_OPT_EXE }, { "implib", 0, LONG_OPT_IMPLIB }, { "staticlib", 0, LONG_OPT_STATICLIB }, @@ -443,6 +447,9 @@ static void option_callback( int optc, char *optarg ) case LONG_OPT_DISABLE_DYNAMICBASE: disable_dynamicbase = 1; break; + case LONG_OPT_DISABLE_HIGH_ENTROPY_VA: + disable_high_entropy_va = 1; + break; case LONG_OPT_EXE: set_exec_mode( MODE_EXE ); if (!main_spec->subsystem) main_spec->subsystem = IMAGE_SUBSYSTEM_WINDOWS_GUI; @@ -605,7 +612,7 @@ int main(int argc, char **argv) else { spec->characteristics |= IMAGE_FILE_LARGE_ADDRESS_AWARE; - if (!disable_dynamicbase) { + if (!disable_high_entropy_va) { spec->dll_characteristics |= IMAGE_DLLCHARACTERISTICS_HIGH_ENTROPY_VA; } } -- GitLab https://gitlab.winehq.org/wine/wine/-/merge_requests/8786
From: Tres Finocchiaro <tres.finocchiaro(a)gmail.com> --- tools/winebuild/main.c | 10 +--------- 1 file changed, 1 insertion(+), 9 deletions(-) diff --git a/tools/winebuild/main.c b/tools/winebuild/main.c index 5f161dae529..ca8ff1d637d 100644 --- a/tools/winebuild/main.c +++ b/tools/winebuild/main.c @@ -37,7 +37,6 @@ int UsePIC = 0; int nb_errors = 0; int display_warnings = 0; int disable_dynamicbase = 0; -int disable_high_entropy_va = 0; int native_arch = -1; int kill_at = 0; int verbose = 0; @@ -185,7 +184,6 @@ static const char usage_str[] = " -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" -" --disable-high-entropy-va Disable high-entropy 64-bit 'ASLR' (default: high-entropy 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" @@ -231,7 +229,6 @@ enum long_options_values LONG_OPT_DLL = 1, LONG_OPT_DEF, LONG_OPT_DISABLE_DYNAMICBASE, - LONG_OPT_DISABLE_HIGH_ENTROPY_VA, LONG_OPT_EXE, LONG_OPT_IMPLIB, LONG_OPT_BUILTIN, @@ -263,7 +260,6 @@ static const struct long_option long_options[] = { "dll", 0, LONG_OPT_DLL }, { "def", 0, LONG_OPT_DEF }, { "disable-dynamicbase", 0, LONG_OPT_DISABLE_DYNAMICBASE }, - { "disable-high-entropy-va", 0, LONG_OPT_DISABLE_HIGH_ENTROPY_VA }, { "exe", 0, LONG_OPT_EXE }, { "implib", 0, LONG_OPT_IMPLIB }, { "staticlib", 0, LONG_OPT_STATICLIB }, @@ -446,10 +442,6 @@ static void option_callback( int optc, char *optarg ) break; case LONG_OPT_DISABLE_DYNAMICBASE: disable_dynamicbase = 1; - break; - case LONG_OPT_DISABLE_HIGH_ENTROPY_VA: - disable_high_entropy_va = 1; - break; case LONG_OPT_EXE: set_exec_mode( MODE_EXE ); if (!main_spec->subsystem) main_spec->subsystem = IMAGE_SUBSYSTEM_WINDOWS_GUI; @@ -612,7 +604,7 @@ int main(int argc, char **argv) else { spec->characteristics |= IMAGE_FILE_LARGE_ADDRESS_AWARE; - if (!disable_high_entropy_va) { + if (!disable_dynamicbase) { spec->dll_characteristics |= IMAGE_DLLCHARACTERISTICS_HIGH_ENTROPY_VA; } } -- GitLab https://gitlab.winehq.org/wine/wine/-/merge_requests/8786
On Wed Aug 20 20:26:37 2025 +0000, Alexandre Julliard wrote:
The only influence is when both flags are set, we stop allocating in the low 2Gb by default, which probably breaks plugins that have pointer truncation bugs. Unless both flags are set together, there shouldn't be any difference for the case of `.exe.so` binaries. There are more differences for the case of PE binaries, but that's controlled by the flags passed to `mingw`, not to `winebuild`. So there's no reason to add two separate options to `winebuild`. Clearing either flag is the same as clearing both. @julliard thanks for clarification. I've reverted the `HIGHENTROPYVA` portions of this MR and resolved the styling questions.
Unless both flags are set together, there shouldn't be any difference for the case of `.exe.so` binaries.
So according to this information, the following code would influence readability only, do you wish to remove it, keep it, or code-comment it? ```c if (!disable_dynamicbase) { spec->dll_characteristics |= IMAGE_DLLCHARACTERISTICS_HIGH_ENTROPY_VA; } ``` -- https://gitlab.winehq.org/wine/wine/-/merge_requests/8786#note_113478
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