1//===-- InstrumentationRuntimeUBSan.cpp -----------------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9#include "InstrumentationRuntimeUBSan.h"
10
11#include "Plugins/Process/Utility/HistoryThread.h"
12#include "lldb/Breakpoint/StoppointCallbackContext.h"
13#include "lldb/Core/Debugger.h"
14#include "lldb/Core/Module.h"
15#include "lldb/Core/PluginInterface.h"
16#include "lldb/Core/PluginManager.h"
17#include "lldb/Core/ValueObject.h"
18#include "lldb/Expression/UserExpression.h"
19#include "lldb/Host/StreamFile.h"
20#include "lldb/Interpreter/CommandReturnObject.h"
21#include "lldb/Symbol/Symbol.h"
22#include "lldb/Symbol/SymbolContext.h"
23#include "lldb/Symbol/Variable.h"
24#include "lldb/Symbol/VariableList.h"
25#include "lldb/Target/InstrumentationRuntimeStopInfo.h"
26#include "lldb/Target/SectionLoadList.h"
27#include "lldb/Target/StopInfo.h"
28#include "lldb/Target/Target.h"
29#include "lldb/Target/Thread.h"
30#include "lldb/Utility/RegularExpression.h"
31#include "lldb/Utility/Stream.h"
32#include <cctype>
33
34#include <memory>
35
36using namespace lldb;
37using namespace lldb_private;
38
39LLDB_PLUGIN_DEFINE(InstrumentationRuntimeUBSan)
40
41InstrumentationRuntimeUBSan::~InstrumentationRuntimeUBSan() { Deactivate(); }
42
43lldb::InstrumentationRuntimeSP
44InstrumentationRuntimeUBSan::CreateInstance(const lldb::ProcessSP &process_sp) {
45 return InstrumentationRuntimeSP(new InstrumentationRuntimeUBSan(process_sp));
46}
47
48void InstrumentationRuntimeUBSan::Initialize() {
49 PluginManager::RegisterPlugin(
50 name: GetPluginNameStatic(),
51 description: "UndefinedBehaviorSanitizer instrumentation runtime plugin.",
52 create_callback: CreateInstance, get_type_callback: GetTypeStatic);
53}
54
55void InstrumentationRuntimeUBSan::Terminate() {
56 PluginManager::UnregisterPlugin(create_callback: CreateInstance);
57}
58
59lldb::InstrumentationRuntimeType InstrumentationRuntimeUBSan::GetTypeStatic() {
60 return eInstrumentationRuntimeTypeUndefinedBehaviorSanitizer;
61}
62
63static const char *ub_sanitizer_retrieve_report_data_prefix = R"(
64extern "C" {
65void
66__ubsan_get_current_report_data(const char **OutIssueKind,
67 const char **OutMessage, const char **OutFilename, unsigned *OutLine,
68 unsigned *OutCol, char **OutMemoryAddr);
69}
70)";
71
72static const char *ub_sanitizer_retrieve_report_data_command = R"(
73struct {
74 const char *issue_kind;
75 const char *message;
76 const char *filename;
77 unsigned line;
78 unsigned col;
79 char *memory_addr;
80} t;
81
82__ubsan_get_current_report_data(&t.issue_kind, &t.message, &t.filename, &t.line,
83 &t.col, &t.memory_addr);
84t;
85)";
86
87static addr_t RetrieveUnsigned(ValueObjectSP return_value_sp,
88 ProcessSP process_sp,
89 const std::string &expression_path) {
90 return return_value_sp->GetValueForExpressionPath(expression: expression_path.c_str())
91 ->GetValueAsUnsigned(fail_value: 0);
92}
93
94static std::string RetrieveString(ValueObjectSP return_value_sp,
95 ProcessSP process_sp,
96 const std::string &expression_path) {
97 addr_t ptr = RetrieveUnsigned(return_value_sp, process_sp, expression_path);
98 std::string str;
99 Status error;
100 process_sp->ReadCStringFromMemory(vm_addr: ptr, out_str&: str, error);
101 return str;
102}
103
104StructuredData::ObjectSP InstrumentationRuntimeUBSan::RetrieveReportData(
105 ExecutionContextRef exe_ctx_ref) {
106 ProcessSP process_sp = GetProcessSP();
107 if (!process_sp)
108 return StructuredData::ObjectSP();
109
110 ThreadSP thread_sp = exe_ctx_ref.GetThreadSP();
111 StackFrameSP frame_sp =
112 thread_sp->GetSelectedFrame(select_most_relevant: DoNoSelectMostRelevantFrame);
113 ModuleSP runtime_module_sp = GetRuntimeModuleSP();
114 Target &target = process_sp->GetTarget();
115
116 if (!frame_sp)
117 return StructuredData::ObjectSP();
118
119 StreamFileSP Stream = target.GetDebugger().GetOutputStreamSP();
120
121 EvaluateExpressionOptions options;
122 options.SetUnwindOnError(true);
123 options.SetTryAllThreads(true);
124 options.SetStopOthers(true);
125 options.SetIgnoreBreakpoints(true);
126 options.SetTimeout(process_sp->GetUtilityExpressionTimeout());
127 options.SetPrefix(ub_sanitizer_retrieve_report_data_prefix);
128 options.SetAutoApplyFixIts(false);
129 options.SetLanguage(eLanguageTypeObjC_plus_plus);
130
131 ValueObjectSP main_value;
132 ExecutionContext exe_ctx;
133 Status eval_error;
134 frame_sp->CalculateExecutionContext(exe_ctx);
135 ExpressionResults result = UserExpression::Evaluate(
136 exe_ctx, options, expr_cstr: ub_sanitizer_retrieve_report_data_command, expr_prefix: "",
137 result_valobj_sp&: main_value, error&: eval_error);
138 if (result != eExpressionCompleted) {
139 StreamString ss;
140 ss << "cannot evaluate UndefinedBehaviorSanitizer expression:\n";
141 ss << eval_error.AsCString();
142 Debugger::ReportWarning(message: ss.GetString().str(),
143 debugger_id: process_sp->GetTarget().GetDebugger().GetID());
144 return StructuredData::ObjectSP();
145 }
146
147 // Gather the PCs of the user frames in the backtrace.
148 StructuredData::Array *trace = new StructuredData::Array();
149 auto trace_sp = StructuredData::ObjectSP(trace);
150 for (unsigned I = 0; I < thread_sp->GetStackFrameCount(); ++I) {
151 const Address FCA = thread_sp->GetStackFrameAtIndex(idx: I)
152 ->GetFrameCodeAddressForSymbolication();
153 if (FCA.GetModule() == runtime_module_sp) // Skip PCs from the runtime.
154 continue;
155
156 lldb::addr_t PC = FCA.GetLoadAddress(target: &target);
157 trace->AddIntegerItem(value: PC);
158 }
159
160 std::string IssueKind = RetrieveString(return_value_sp: main_value, process_sp, expression_path: ".issue_kind");
161 std::string ErrMessage = RetrieveString(return_value_sp: main_value, process_sp, expression_path: ".message");
162 std::string Filename = RetrieveString(return_value_sp: main_value, process_sp, expression_path: ".filename");
163 unsigned Line = RetrieveUnsigned(return_value_sp: main_value, process_sp, expression_path: ".line");
164 unsigned Col = RetrieveUnsigned(return_value_sp: main_value, process_sp, expression_path: ".col");
165 uintptr_t MemoryAddr =
166 RetrieveUnsigned(return_value_sp: main_value, process_sp, expression_path: ".memory_addr");
167
168 auto *d = new StructuredData::Dictionary();
169 auto dict_sp = StructuredData::ObjectSP(d);
170 d->AddStringItem(key: "instrumentation_class", value: "UndefinedBehaviorSanitizer");
171 d->AddStringItem(key: "description", value: IssueKind);
172 d->AddStringItem(key: "summary", value: ErrMessage);
173 d->AddStringItem(key: "filename", value: Filename);
174 d->AddIntegerItem(key: "line", value: Line);
175 d->AddIntegerItem(key: "col", value: Col);
176 d->AddIntegerItem(key: "memory_address", value: MemoryAddr);
177 d->AddIntegerItem(key: "tid", value: thread_sp->GetID());
178 d->AddItem(key: "trace", value_sp: trace_sp);
179 return dict_sp;
180}
181
182static std::string GetStopReasonDescription(StructuredData::ObjectSP report) {
183 llvm::StringRef stop_reason_description_ref;
184 report->GetAsDictionary()->GetValueForKeyAsString(
185 key: "description", result&: stop_reason_description_ref);
186 std::string stop_reason_description =
187 std::string(stop_reason_description_ref);
188
189 if (!stop_reason_description.size()) {
190 stop_reason_description = "Undefined behavior detected";
191 } else {
192 stop_reason_description[0] = toupper(c: stop_reason_description[0]);
193 for (unsigned I = 1; I < stop_reason_description.size(); ++I)
194 if (stop_reason_description[I] == '-')
195 stop_reason_description[I] = ' ';
196 }
197 return stop_reason_description;
198}
199
200bool InstrumentationRuntimeUBSan::NotifyBreakpointHit(
201 void *baton, StoppointCallbackContext *context, user_id_t break_id,
202 user_id_t break_loc_id) {
203 assert(baton && "null baton");
204 if (!baton)
205 return false; ///< false => resume execution.
206
207 InstrumentationRuntimeUBSan *const instance =
208 static_cast<InstrumentationRuntimeUBSan *>(baton);
209
210 ProcessSP process_sp = instance->GetProcessSP();
211 ThreadSP thread_sp = context->exe_ctx_ref.GetThreadSP();
212 if (!process_sp || !thread_sp ||
213 process_sp != context->exe_ctx_ref.GetProcessSP())
214 return false;
215
216 if (process_sp->GetModIDRef().IsLastResumeForUserExpression())
217 return false;
218
219 StructuredData::ObjectSP report =
220 instance->RetrieveReportData(exe_ctx_ref: context->exe_ctx_ref);
221
222 if (report) {
223 thread_sp->SetStopInfo(
224 InstrumentationRuntimeStopInfo::CreateStopReasonWithInstrumentationData(
225 thread&: *thread_sp, description: GetStopReasonDescription(report), additional_data: report));
226 return true;
227 }
228
229 return false;
230}
231
232const RegularExpression &
233InstrumentationRuntimeUBSan::GetPatternForRuntimeLibrary() {
234 static RegularExpression regex(llvm::StringRef("libclang_rt\\.(a|t|ub)san_"));
235 return regex;
236}
237
238bool InstrumentationRuntimeUBSan::CheckIfRuntimeIsValid(
239 const lldb::ModuleSP module_sp) {
240 static ConstString ubsan_test_sym("__ubsan_on_report");
241 const Symbol *symbol = module_sp->FindFirstSymbolWithNameAndType(
242 name: ubsan_test_sym, symbol_type: lldb::eSymbolTypeAny);
243 return symbol != nullptr;
244}
245
246// FIXME: Factor out all the logic we have in common with the {a,t}san plugins.
247void InstrumentationRuntimeUBSan::Activate() {
248 if (IsActive())
249 return;
250
251 ProcessSP process_sp = GetProcessSP();
252 if (!process_sp)
253 return;
254
255 ModuleSP runtime_module_sp = GetRuntimeModuleSP();
256
257 ConstString symbol_name("__ubsan_on_report");
258 const Symbol *symbol = runtime_module_sp->FindFirstSymbolWithNameAndType(
259 name: symbol_name, symbol_type: eSymbolTypeCode);
260
261 if (symbol == nullptr)
262 return;
263
264 if (!symbol->ValueIsAddress() || !symbol->GetAddressRef().IsValid())
265 return;
266
267 Target &target = process_sp->GetTarget();
268 addr_t symbol_address = symbol->GetAddressRef().GetOpcodeLoadAddress(target: &target);
269
270 if (symbol_address == LLDB_INVALID_ADDRESS)
271 return;
272
273 Breakpoint *breakpoint =
274 process_sp->GetTarget()
275 .CreateBreakpoint(load_addr: symbol_address, /*internal=*/true,
276 /*hardware=*/request_hardware: false)
277 .get();
278 const bool sync = false;
279 breakpoint->SetCallback(callback: InstrumentationRuntimeUBSan::NotifyBreakpointHit,
280 baton: this, is_synchronous: sync);
281 breakpoint->SetBreakpointKind("undefined-behavior-sanitizer-report");
282 SetBreakpointID(breakpoint->GetID());
283
284 SetActive(true);
285}
286
287void InstrumentationRuntimeUBSan::Deactivate() {
288 SetActive(false);
289
290 auto BID = GetBreakpointID();
291 if (BID == LLDB_INVALID_BREAK_ID)
292 return;
293
294 if (ProcessSP process_sp = GetProcessSP()) {
295 process_sp->GetTarget().RemoveBreakpointByID(break_id: BID);
296 SetBreakpointID(LLDB_INVALID_BREAK_ID);
297 }
298}
299
300lldb::ThreadCollectionSP
301InstrumentationRuntimeUBSan::GetBacktracesFromExtendedStopInfo(
302 StructuredData::ObjectSP info) {
303 ThreadCollectionSP threads;
304 threads = std::make_shared<ThreadCollection>();
305
306 ProcessSP process_sp = GetProcessSP();
307
308 if (info->GetObjectForDotSeparatedPath(path: "instrumentation_class")
309 ->GetStringValue() != "UndefinedBehaviorSanitizer")
310 return threads;
311
312 std::vector<lldb::addr_t> PCs;
313 auto trace = info->GetObjectForDotSeparatedPath(path: "trace")->GetAsArray();
314 trace->ForEach(foreach_callback: [&PCs](StructuredData::Object *PC) -> bool {
315 PCs.push_back(x: PC->GetUnsignedIntegerValue());
316 return true;
317 });
318
319 if (PCs.empty())
320 return threads;
321
322 StructuredData::ObjectSP thread_id_obj =
323 info->GetObjectForDotSeparatedPath(path: "tid");
324 tid_t tid = thread_id_obj ? thread_id_obj->GetUnsignedIntegerValue() : 0;
325
326 // We gather symbolication addresses above, so no need for HistoryThread to
327 // try to infer the call addresses.
328 bool pcs_are_call_addresses = true;
329 ThreadSP new_thread_sp = std::make_shared<HistoryThread>(
330 args&: *process_sp, args&: tid, args&: PCs, args&: pcs_are_call_addresses);
331 std::string stop_reason_description = GetStopReasonDescription(report: info);
332 new_thread_sp->SetName(stop_reason_description.c_str());
333
334 // Save this in the Process' ExtendedThreadList so a strong pointer retains
335 // the object
336 process_sp->GetExtendedThreadList().AddThread(thread_sp: new_thread_sp);
337 threads->AddThread(thread_sp: new_thread_sp);
338
339 return threads;
340}
341

source code of lldb/source/Plugins/InstrumentationRuntime/UBSan/InstrumentationRuntimeUBSan.cpp