Milestone 5: deliver embedded RDP sessions and lifecycle hardening

third_party/FreeRDP/winpr/libwinpr/utils/unwind/debug.c

@@ -0,0 +1,206 @@
+/**
+ * WinPR: Windows Portable Runtime
+ * WinPR Debugging helpers
+ *
+ * Copyright 2022 Armin Novak <armin.novak@thincast.com>
+ * Copyright 2022 Thincast Technologies GmbH
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE // NOLINT(bugprone-reserved-identifier,cert-dcl37-c,cert-dcl51-cpp)
+#endif
+
+#include <assert.h>
+#include <stdlib.h>
+#include <unwind.h>
+
+#include <winpr/string.h>
+#include "debug.h"
+
+#include <winpr/wlog.h>
+#include "../log.h"
+
+#include <dlfcn.h>
+
+#define TAG WINPR_TAG("utils.unwind")
+
+#define UNWIND_MAX_LINE_SIZE 1024ULL
+
+typedef struct
+{
+	union
+	{
+		uintptr_t uw;
+		void* pv;
+	} pc;
+	union
+	{
+		uintptr_t uptr;
+		void* pv;
+	} langSpecificData;
+} unwind_info_t;
+
+typedef struct
+{
+	size_t pos;
+	size_t size;
+	unwind_info_t* info;
+} unwind_context_t;
+
+static const char* unwind_reason_str(_Unwind_Reason_Code code)
+{
+	switch (code)
+	{
+#if defined(__arm__) && !defined(__USING_SJLJ_EXCEPTIONS__) && !defined(__ARM_DWARF_EH__) && \
+    !defined(__SEH__)
+		case _URC_OK:
+			return "_URC_OK";
+#else
+		case _URC_NO_REASON:
+			return "_URC_NO_REASON";
+		case _URC_FATAL_PHASE2_ERROR:
+			return "_URC_FATAL_PHASE2_ERROR";
+		case _URC_FATAL_PHASE1_ERROR:
+			return "_URC_FATAL_PHASE1_ERROR";
+		case _URC_NORMAL_STOP:
+			return "_URC_NORMAL_STOP";
+#endif
+		case _URC_FOREIGN_EXCEPTION_CAUGHT:
+			return "_URC_FOREIGN_EXCEPTION_CAUGHT";
+		case _URC_END_OF_STACK:
+			return "_URC_END_OF_STACK";
+		case _URC_HANDLER_FOUND:
+			return "_URC_HANDLER_FOUND";
+		case _URC_INSTALL_CONTEXT:
+			return "_URC_INSTALL_CONTEXT";
+		case _URC_CONTINUE_UNWIND:
+			return "_URC_CONTINUE_UNWIND";
+#if defined(__arm__) && !defined(__USING_SJLJ_EXCEPTIONS__) && !defined(__ARM_DWARF_EH__) && \
+    !defined(__SEH__)
+		case _URC_FAILURE:
+			return "_URC_FAILURE";
+#endif
+		default:
+			return "_URC_UNKNOWN";
+	}
+}
+
+static const char* unwind_reason_str_buffer(_Unwind_Reason_Code code, char* buffer, size_t size)
+{
+	const char* str = unwind_reason_str(code);
+	(void)_snprintf(buffer, size, "%s [0x%02x]", str, code);
+	return buffer;
+}
+
+static _Unwind_Reason_Code unwind_backtrace_callback(struct _Unwind_Context* context, void* arg)
+{
+	unwind_context_t* ctx = arg;
+
+	assert(ctx);
+
+	if (ctx->pos < ctx->size)
+	{
+		unwind_info_t* info = &ctx->info[ctx->pos++];
+		info->pc.uw = _Unwind_GetIP(context);
+
+		/* _Unwind_GetLanguageSpecificData has various return value definitions,
+		 * cast to the type we expect and disable linter warnings
+		 */
+		// NOLINTNEXTLINE(google-readability-casting,readability-redundant-casting)
+		info->langSpecificData.pv = (void*)_Unwind_GetLanguageSpecificData(context);
+	}
+
+	return _URC_NO_REASON;
+}
+
+void* winpr_unwind_backtrace(DWORD size)
+{
+	_Unwind_Reason_Code rc = _URC_FOREIGN_EXCEPTION_CAUGHT;
+	unwind_context_t* ctx = calloc(1, sizeof(unwind_context_t));
+	if (!ctx)
+		goto fail;
+	ctx->size = size;
+	ctx->info = calloc(size, sizeof(unwind_info_t));
+	if (!ctx->info)
+		goto fail;
+
+	rc = _Unwind_Backtrace(unwind_backtrace_callback, ctx);
+	if (rc != _URC_END_OF_STACK)
+	{
+		/* https://github.com/FreeRDP/FreeRDP/issues/11490
+		 *
+		 * there seems to be no consensus on what to return from this function.
+		 * so we just warn about unexpected return codes and return the context regardless.
+		 */
+		char buffer[64] = WINPR_C_ARRAY_INIT;
+		WLog_WARN(TAG, "_Unwind_Backtrace failed with %s",
+		          unwind_reason_str_buffer(rc, buffer, sizeof(buffer)));
+	}
+
+	return ctx;
+fail:
+	winpr_unwind_backtrace_free(ctx);
+	return nullptr;
+}
+
+void winpr_unwind_backtrace_free(void* buffer)
+{
+	unwind_context_t* ctx = buffer;
+	if (!ctx)
+		return;
+	free(ctx->info);
+	free(ctx);
+}
+
+char** winpr_unwind_backtrace_symbols(void* buffer, size_t* used)
+{
+	union
+	{
+		void* pv;
+		char* cp;
+		char** cpp;
+	} cnv;
+	unwind_context_t* ctx = buffer;
+	cnv.cpp = nullptr;
+
+	if (!ctx)
+		return nullptr;
+
+	cnv.pv = calloc(ctx->pos * (sizeof(char*) + UNWIND_MAX_LINE_SIZE), sizeof(char*));
+	if (!cnv.pv)
+		return nullptr;
+
+	if (used)
+		*used = ctx->pos;
+
+	for (size_t x = 0; x < ctx->pos; x++)
+	{
+		char* msg = cnv.cp + ctx->pos * sizeof(char*) + x * UNWIND_MAX_LINE_SIZE;
+		const unwind_info_t* info = &ctx->info[x];
+		Dl_info dlinfo = WINPR_C_ARRAY_INIT;
+		int rc = dladdr(info->pc.pv, &dlinfo);
+
+		cnv.cpp[x] = msg;
+
+		if (rc == 0)
+			(void)_snprintf(msg, UNWIND_MAX_LINE_SIZE, "unresolvable, address=%p", info->pc.pv);
+		else
+			(void)_snprintf(msg, UNWIND_MAX_LINE_SIZE, "dli_fname=%s [%p], dli_sname=%s [%p]",
+			                dlinfo.dli_fname, dlinfo.dli_fbase, dlinfo.dli_sname, dlinfo.dli_saddr);
+	}
+
+	// NOLINTNEXTLINE(clang-analyzer-unix.Malloc): function is an allocator
+	return cnv.cpp;
+}