Revert "SafeStack: Add a SafeStack build configuration"

SafeStack support has been abandoned.

Bug: 908597
Change-Id: Ie4e8709c4682814fb7bebad2eb2a65990f69c3d0
Reviewed-on: https://chromium-review.googlesource.com/c/1351587
Commit-Queue: Vlad Tsyrklevich <vtsyrklevich@chromium.org>
Reviewed-by: Nico Weber <thakis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#611286}

build/config/compiler/BUILD.gn

@@ -393,7 +393,7 @@ config("compiler") {
 
     # Compiler instrumentation can introduce dependencies in DSOs to symbols in
     # the executable they are loaded into, so they are unresolved at link-time.
-    if (!using_sanitizer && !is_safestack) {
+    if (!using_sanitizer) {
       ldflags += [
         "-Wl,-z,defs",
         "-Wl,--as-needed",

build/config/sanitizers/BUILD.gn

@@ -197,9 +197,6 @@ config("default_sanitizer_ldflags") {
     if (is_ubsan_vptr) {
       ldflags += [ "-fsanitize=vptr" ]
     }
-    if (is_safestack) {
-      ldflags += [ "-fsanitize=safe-stack" ]
-    }
 
     if (use_sanitizer_coverage) {
       if (use_libfuzzer) {
@@ -440,12 +437,6 @@ config("msan_flags") {
   }
 }
 
-config("safestack_flags") {
-  if (is_safestack) {
-    cflags = [ "-fsanitize=safe-stack" ]
-  }
-}
-
 config("tsan_flags") {
   if (is_tsan) {
     assert(is_linux, "tsan only supported on linux x86_64")
@@ -561,7 +552,6 @@ all_sanitizer_configs = [
   ":cfi_flags",
   ":lsan_flags",
   ":msan_flags",
-  ":safestack_flags",
   ":tsan_flags",
   ":ubsan_flags",
   ":ubsan_no_recover",

build/config/sanitizers/sanitizers.gni

@@ -33,9 +33,6 @@ declare_args() {
   # Compile for Undefined Behaviour Sanitizer's vptr checks.
   is_ubsan_vptr = false
 
-  # Compile with SafeStack shadow stack support.
-  is_safestack = false
-
   # Track where uninitialized memory originates from. From fastest to slowest:
   # 0 - no tracking, 1 - track only the initial allocation site, 2 - track the
   # chain of stores leading from allocation site to use site.
@@ -158,9 +155,9 @@ if (use_fuzzing_engine && sanitizer_coverage_flags == "") {
   sanitizer_coverage_flags = "trace-pc-guard,indirect-calls"
 }
 
-# Whether we are linking against a debugging sanitizer runtime library. Among
-# other things, this changes the default symbol level and other settings in
-# order to prepare to create stack traces "live" using the sanitizer runtime.
+# Whether we are linking against a sanitizer runtime library. Among other
+# things, this changes the default symbol level and other settings in order to
+# prepare to create stack traces "live" using the sanitizer runtime.
 using_sanitizer =
     is_asan || is_lsan || is_tsan || is_msan || is_ubsan || is_ubsan_null ||
     is_ubsan_vptr || is_ubsan_security || use_sanitizer_coverage || use_cfi_diag
@@ -171,9 +168,6 @@ assert(!using_sanitizer || is_clang,
 assert(!is_cfi || is_clang,
        "is_cfi requires setting is_clang = true in 'gn args'")
 
-assert(!is_safestack || is_clang,
-       "is_safestack requires setting is_clang = true in 'gn args'")
-
 prebuilt_instrumented_libraries_available =
     is_msan && (msan_track_origins == 0 || msan_track_origins == 2)
 

build/linux/chrome.safestack.map

-# This is a separate SafeStack version script to avoid accidentally exporting
-# a pthread_create symbol in the default build
-{
-global:
-  __bss_start;
-  __data_start;
-  data_start;
-  _edata;
-  _end;
-  _IO_stdin_used;
-
-  # Initialization and finalization functions for static global
-  # variables.
-  _fini;
-  _init;
-  __libc_csu_fini;
-  __libc_csu_init;
-
-  # Chrome's main function.  Exported for historical purposes.
-  ChromeMain;
-
-  # Program entry point.
-  _start;
-
-  # Memory allocation symbols.  We want chrome and any libraries to
-  # share the same heap, so it is correct to export these symbols.
-  calloc;
-  cfree;
-  free;
-  __free_hook;
-  __libc_calloc;
-  __libc_cfree;
-  __libc_free;
-  __libc_malloc;
-  __libc_memalign;
-  __libc_pvalloc;
-  __libc_realloc;
-  __libc_valloc;
-  mallinfo;
-  malloc;
-  __malloc_hook;
-  malloc_size;
-  malloc_stats;
-  malloc_usable_size;
-  mallopt;
-  memalign;
-  __memalign_hook;
-  __posix_memalign;
-  posix_memalign;
-  pvalloc;
-  realloc;
-  __realloc_hook;
-  valloc;
-
-  # Various flavors of operator new and operator delete.
-  _ZdaPv;
-  _ZdaPvm;
-  _ZdaPvmSt11align_val_t;
-  _ZdaPvRKSt9nothrow_t;
-  _ZdaPvSt11align_val_t;
-  _ZdaPvSt11align_val_tRKSt9nothrow_t;
-  _ZdlPv;
-  _ZdlPvm;
-  _ZdlPvmSt11align_val_t;
-  _ZdlPvRKSt9nothrow_t;
-  _ZdlPvSt11align_val_t;
-  _ZdlPvSt11align_val_tRKSt9nothrow_t;
-  _Znam;
-  _ZnamRKSt9nothrow_t;
-  _ZnamSt11align_val_t;
-  _ZnamSt11align_val_tRKSt9nothrow_t;
-  _Znwm;
-  _ZnwmRKSt9nothrow_t;
-  _ZnwmSt11align_val_t;
-  _ZnwmSt11align_val_tRKSt9nothrow_t;
-
-  # Various flavors of localtime().  These are exported by the chrome
-  # sandbox to intercept calls to localtime(), which would otherwise
-  # fail in untrusted processes that don't have permission to read
-  # /etc/localtime.  These overrides forward the request to the browser
-  # process, which uses dlsym(localtime) to make the real calls.
-  localtime;
-  localtime64;
-  localtime64_r;
-  localtime_r;
-
-  # The SafeStack runtime overrides thread creation routines to allocate shadow
-  # stacks on thread creation.
-  pthread_create;
-
-local:
-  *;
-};

chrome/BUILD.gn

@@ -283,11 +283,7 @@ if (!is_android && !is_mac) {
         }
 
         if (is_desktop_linux && !is_component_build && !using_sanitizer) {
-          if (is_safestack) {
-            version_script = "//build/linux/chrome.safestack.map"
-          } else {
-            version_script = "//build/linux/chrome.map"
-          }
+          version_script = "//build/linux/chrome.map"
           inputs = [
             version_script,
           ]