[runtime] Disable guard stack overflow guard page on darwin

On macOS Mojave, it seems that changing the mapping of stack pages can lead to corruption bugs. mono#10802
BrzVlad · Oct 1, 2018 · c79f751 · c79f751
1 parent 23c4de0
commit c79f751
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Showing 5 changed files with 27 additions and 1 deletion.
diff --git a/configure.ac b/configure.ac
@@ -330,6 +330,7 @@ case "$host" in
 		need_link_unlink=yes
 		AC_DEFINE(PTHREAD_POINTER_ID)
 		AC_DEFINE(USE_MACH_SEMA, 1, [...])
+		AC_DEFINE(DISABLE_STACK_OVERFLOW_GUARD, 1, [Mapping of stack guard page is buggy on platform])
 		libdl=
 		libgc_threads=pthreads
 		has_dtrace=yes

diff --git a/mono/mini/exceptions-amd64.c b/mono/mini/exceptions-amd64.c
@@ -811,6 +811,7 @@ mono_arch_ip_from_context (void *sigctx)
 #endif	
 }
 
+#ifndef DISABLE_STACK_OVERFLOW_GUARD
 static MonoObject*
 restore_soft_guard_pages (void)
 {
@@ -844,6 +845,7 @@ prepare_for_guard_pages (MonoContext *mctx)
 	mctx->gregs [AMD64_RIP] = (guint64)restore_soft_guard_pages;
 	mctx->gregs [AMD64_RSP] = (guint64)sp;
 }
+#endif
 
 static void
 altstack_handle_and_restore (MonoContext *ctx, MonoObject *obj, gboolean stack_ovf)
@@ -858,9 +860,13 @@ altstack_handle_and_restore (MonoContext *ctx, MonoObject *obj, gboolean stack_o
 
 	mono_handle_exception (&mctx, obj);
 	if (stack_ovf) {
+#ifndef DISABLE_STACK_OVERFLOW_GUARD
 		MonoJitTlsData *jit_tls = mono_tls_get_jit_tls ();
 		jit_tls->stack_ovf_pending = 1;
 		prepare_for_guard_pages (&mctx);
+#else
+		g_error ("Soft stack overflow should be disabled");
+#endif
 	}
 	mono_restore_context (&mctx);
 }

diff --git a/mono/mini/exceptions-x86.c b/mono/mini/exceptions-x86.c
@@ -1037,6 +1037,7 @@ mono_arch_handle_exception (void *sigctx, gpointer obj)
 #endif
 }
 
+#ifndef DISABLE_STACK_OVERFLOW_GUARD
 static MonoObject*
 restore_soft_guard_pages ()
 {
@@ -1070,7 +1071,7 @@ prepare_for_guard_pages (MonoContext *mctx)
 	mctx->eip = (unsigned long)restore_soft_guard_pages;
 	mctx->esp = (unsigned long)sp;
 }
-
+#endif
 
 static void
 altstack_handle_and_restore (MonoContext *ctx, gpointer obj, gboolean stack_ovf)
@@ -1081,9 +1082,13 @@ altstack_handle_and_restore (MonoContext *ctx, gpointer obj, gboolean stack_ovf)
 
 	mono_handle_exception (&mctx, (MonoObject*)obj);
 	if (stack_ovf) {
+#ifndef DISABLE_STACK_OVERFLOW_GUARD
 		MonoJitTlsData *jit_tls = mono_tls_get_jit_tls ();
 		jit_tls->stack_ovf_pending = 1;
 		prepare_for_guard_pages (&mctx);
+#else
+		g_error ("Soft stack overflow should be disabled");
+#endif
 	}
 	mono_restore_context (&mctx);
 }

diff --git a/mono/mini/mini-exceptions.c b/mono/mini/mini-exceptions.c
@@ -2745,6 +2745,7 @@ mono_setup_altstack (MonoJitTlsData *tls)
 
 	/*g_print ("thread %p, stack_base: %p, stack_size: %d\n", (gpointer)pthread_self (), staddr, stsize);*/
 
+#ifndef DISABLE_STACK_OVERFLOW_GUARD
 	tls->stack_ovf_guard_base = staddr + mono_pagesize ();
 	tls->stack_ovf_guard_size = ALIGN_TO (8 * 4096, mono_pagesize ());
 
@@ -2756,6 +2757,7 @@ mono_setup_altstack (MonoJitTlsData *tls)
 		g_assert (gaddr == tls->stack_ovf_guard_base);
 		tls->stack_ovf_valloced = TRUE;
 	}
+#endif
 
 	/* Setup an alternate signal stack */
 	tls->signal_stack = mono_valloc (0, MONO_ARCH_SIGNAL_STACK_SIZE, MONO_MMAP_READ|MONO_MMAP_WRITE|MONO_MMAP_PRIVATE|MONO_MMAP_ANON, MONO_MEM_ACCOUNT_EXCEPTIONS);
@@ -2768,7 +2770,11 @@ mono_setup_altstack (MonoJitTlsData *tls)
 	sa.ss_flags = 0;
 	g_assert (sigaltstack (&sa, NULL) == 0);
 
+#ifndef DISABLE_STACK_OVERFLOW_GUARD
 	mono_gc_register_altstack ((char*)tls->stack_ovf_guard_base + tls->stack_ovf_guard_size, (char*)staddr + stsize - ((char*)tls->stack_ovf_guard_base + tls->stack_ovf_guard_size), tls->signal_stack, tls->signal_stack_size);
+#else
+	mono_gc_register_altstack (staddr, stsize, tls->signal_stack, tls->signal_stack_size);
+#endif
 }
 
 void
@@ -2785,10 +2791,12 @@ mono_free_altstack (MonoJitTlsData *tls)
 
 	if (tls->signal_stack)
 		mono_vfree (tls->signal_stack, MONO_ARCH_SIGNAL_STACK_SIZE, MONO_MEM_ACCOUNT_EXCEPTIONS);
+#ifndef DISABLE_STACK_OVERFLOW_GUARD
 	if (tls->stack_ovf_valloced)
 		mono_vfree (tls->stack_ovf_guard_base, tls->stack_ovf_guard_size, MONO_MEM_ACCOUNT_EXCEPTIONS);
 	else
 		mono_mprotect (tls->stack_ovf_guard_base, tls->stack_ovf_guard_size, MONO_MMAP_READ|MONO_MMAP_WRITE);
+#endif
 }
 
 #else /* !MONO_ARCH_SIGSEGV_ON_ALTSTACK */
@@ -2808,6 +2816,9 @@ mono_free_altstack (MonoJitTlsData *tls)
 gboolean
 mono_handle_soft_stack_ovf (MonoJitTlsData *jit_tls, MonoJitInfo *ji, void *ctx, MONO_SIG_HANDLER_INFO_TYPE *siginfo, guint8* fault_addr)
 {
+#ifdef DISABLE_STACK_OVERFLOW_GUARD
+	return FALSE;
+#else
 	if (mono_llvm_only)
 		return FALSE;
 
@@ -2847,6 +2858,7 @@ mono_handle_soft_stack_ovf (MonoJitTlsData *jit_tls, MonoJitInfo *ji, void *ctx,
 		return TRUE;
 	}
 	return FALSE;
+#endif
 }
 
 typedef struct {

diff --git a/mono/mini/mini-runtime.h b/mono/mini/mini-runtime.h
@@ -83,10 +83,12 @@ struct MonoJitTlsData {
 	guint            handling_stack_ovf : 1;
 	gpointer         signal_stack;
 	guint32          signal_stack_size;
+#ifndef DISABLE_STACK_OVERFLOW_GUARD
 	gpointer         stack_ovf_guard_base;
 	guint32          stack_ovf_guard_size;
 	guint            stack_ovf_valloced : 1;
 	guint            stack_ovf_pending : 1;
+#endif
 	MonoAbortFunction abort_func;
 	/* Used to implement --debug=casts */
 	MonoClass       *class_cast_from, *class_cast_to;