[clang] 9f517fd - [clang][analyzer] Improve bug report in alpha.security.ReturnPtrRange
Balázs Kéri via cfe-commits
cfe-commits at lists.llvm.org
Wed Aug 11 03:52:27 PDT 2021
Author: Balázs Kéri
Date: 2021-08-11T13:04:55+02:00
New Revision: 9f517fd11ee9b9e49eabff7400cfe13b424e9b06
URL: https://github.com/llvm/llvm-project/commit/9f517fd11ee9b9e49eabff7400cfe13b424e9b06
DIFF: https://github.com/llvm/llvm-project/commit/9f517fd11ee9b9e49eabff7400cfe13b424e9b06.diff
LOG: [clang][analyzer] Improve bug report in alpha.security.ReturnPtrRange
Add some notes and track of bad return value.
Reviewed By: steakhal
Differential Revision: https://reviews.llvm.org/D107051
Added:
Modified:
clang/lib/StaticAnalyzer/Checkers/ReturnPointerRangeChecker.cpp
clang/test/Analysis/misc-ps-region-store.m
clang/test/Analysis/return-ptr-range.cpp
Removed:
################################################################################
diff --git a/clang/lib/StaticAnalyzer/Checkers/ReturnPointerRangeChecker.cpp b/clang/lib/StaticAnalyzer/Checkers/ReturnPointerRangeChecker.cpp
index 885750218b9e5..c4dc06d4a0777 100644
--- a/clang/lib/StaticAnalyzer/Checkers/ReturnPointerRangeChecker.cpp
+++ b/clang/lib/StaticAnalyzer/Checkers/ReturnPointerRangeChecker.cpp
@@ -12,6 +12,7 @@
//===----------------------------------------------------------------------===//
#include "clang/StaticAnalyzer/Checkers/BuiltinCheckerRegistration.h"
+#include "clang/StaticAnalyzer/Core/BugReporter/BugReporterVisitors.h"
#include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"
#include "clang/StaticAnalyzer/Core/Checker.h"
#include "clang/StaticAnalyzer/Core/CheckerManager.h"
@@ -79,16 +80,44 @@ void ReturnPointerRangeChecker::checkPreStmt(const ReturnStmt *RS,
"Returned pointer value points outside the original object "
"(potential buffer overflow)"));
- // FIXME: It would be nice to eventually make this diagnostic more clear,
- // e.g., by referencing the original declaration or by saying *why* this
- // reference is outside the range.
-
// Generate a report for this bug.
- auto report =
+ auto Report =
std::make_unique<PathSensitiveBugReport>(*BT, BT->getDescription(), N);
-
- report->addRange(RetE->getSourceRange());
- C.emitReport(std::move(report));
+ Report->addRange(RetE->getSourceRange());
+
+ const auto ConcreteElementCount = ElementCount.getAs<nonloc::ConcreteInt>();
+ const auto ConcreteIdx = Idx.getAs<nonloc::ConcreteInt>();
+
+ const auto *DeclR = ER->getSuperRegion()->getAs<DeclRegion>();
+
+ if (DeclR)
+ Report->addNote("Original object declared here",
+ {DeclR->getDecl(), C.getSourceManager()});
+
+ if (ConcreteElementCount) {
+ SmallString<128> SBuf;
+ llvm::raw_svector_ostream OS(SBuf);
+ OS << "Original object ";
+ if (DeclR) {
+ OS << "'";
+ DeclR->getDecl()->printName(OS);
+ OS << "' ";
+ }
+ OS << "is an array of " << ConcreteElementCount->getValue() << " '";
+ ER->getValueType().print(OS,
+ PrintingPolicy(C.getASTContext().getLangOpts()));
+ OS << "' objects";
+ if (ConcreteIdx) {
+ OS << ", returned pointer points at index " << ConcreteIdx->getValue();
+ }
+
+ Report->addNote(SBuf,
+ {RetE, C.getSourceManager(), C.getLocationContext()});
+ }
+
+ bugreporter::trackExpressionValue(N, RetE, *Report);
+
+ C.emitReport(std::move(Report));
}
}
diff --git a/clang/test/Analysis/misc-ps-region-store.m b/clang/test/Analysis/misc-ps-region-store.m
index 9c31324e7e59d..6332ff5a50103 100644
--- a/clang/test/Analysis/misc-ps-region-store.m
+++ b/clang/test/Analysis/misc-ps-region-store.m
@@ -461,10 +461,11 @@ void element_region_with_symbolic_superregion(int* p) {
// Test returning an out-of-bounds pointer (CWE-466)
//===----------------------------------------------------------------------===//
-static int test_cwe466_return_outofbounds_pointer_a[10];
+static int test_cwe466_return_outofbounds_pointer_a[10]; // expected-note{{Original object declared here}}
int *test_cwe466_return_outofbounds_pointer() {
int *p = test_cwe466_return_outofbounds_pointer_a+11;
return p; // expected-warning{{Returned pointer value points outside the original object}}
+ // expected-note at -1{{Original object 'test_cwe466_return_outofbounds_pointer_a' is an array of 10 'int' objects, returned pointer points at index 11}}
}
//===----------------------------------------------------------------------===//
diff --git a/clang/test/Analysis/return-ptr-range.cpp b/clang/test/Analysis/return-ptr-range.cpp
index 9763b51264e6f..34c953ee213b7 100644
--- a/clang/test/Analysis/return-ptr-range.cpp
+++ b/clang/test/Analysis/return-ptr-range.cpp
@@ -1,29 +1,39 @@
-// RUN: %clang_analyze_cc1 -analyzer-checker=alpha.security.ReturnPtrRange -verify %s
-
-int arr[10];
-int *ptr;
+// RUN: %clang_analyze_cc1 -analyzer-checker=core,alpha.security.ReturnPtrRange -analyzer-output text -verify %s
int conjure_index();
-int *test_element_index_lifetime() {
- do {
+namespace test_element_index_lifetime {
+
+int arr[10]; // expected-note{{Original object declared here}} expected-note{{Original object declared here}}
+int *ptr;
+
+int *test_global_ptr() {
+ do { // expected-note{{Loop condition is false. Exiting loop}}
int x = conjure_index();
- ptr = arr + x;
- if (x != 20)
+ ptr = arr + x; // expected-note{{Value assigned to 'ptr'}}
+ if (x != 20) // expected-note{{Assuming 'x' is equal to 20}}
+ // expected-note at -1{{Taking false branch}}
return arr; // no-warning
- } while (0);
- return ptr; // expected-warning{{Returned pointer value points outside the original object (potential buffer overflow)}}
+ } while(0);
+ return ptr; // expected-warning{{Returned pointer value points outside the original object (potential buffer overflow) [alpha.security.ReturnPtrRange]}}
+ // expected-note at -1{{Returned pointer value points outside the original object (potential buffer overflow)}}
+ // expected-note at -2{{Original object 'arr' is an array of 10 'int' objects}}
}
-int *test_element_index_lifetime_with_local_ptr() {
+int *test_local_ptr() {
int *local_ptr;
- do {
+ do { // expected-note{{Loop condition is false. Exiting loop}}
int x = conjure_index();
- local_ptr = arr + x;
- if (x != 20)
+ local_ptr = arr + x; // expected-note{{Value assigned to 'local_ptr'}}
+ if (x != 20) // expected-note{{Assuming 'x' is equal to 20}}
+ // expected-note at -1{{Taking false branch}}
return arr; // no-warning
- } while (0);
- return local_ptr; // expected-warning{{Returned pointer value points outside the original object (potential buffer overflow)}}
+ } while(0);
+ return local_ptr; // expected-warning{{Returned pointer value points outside the original object (potential buffer overflow) [alpha.security.ReturnPtrRange]}}
+ // expected-note at -1{{Returned pointer value points outside the original object (potential buffer overflow)}}
+ // expected-note at -2{{Original object 'arr' is an array of 10 'int' objects}}
+}
+
}
template <typename T, int N>
@@ -55,17 +65,53 @@ void use_iterable_object() {
template <int N>
class BadIterable {
- int buffer[N];
+ int buffer[N]; // expected-note{{Original object declared here}}
int *start, *finish;
public:
- BadIterable() : start(buffer), finish(buffer + N) {}
+ BadIterable() : start(buffer), finish(buffer + N) {} // expected-note{{Value assigned to 'iter.finish'}}
int* begin() { return start; }
- int* end() { return finish + 1; } // expected-warning{{Returned pointer value points outside the original object (potential buffer overflow)}}
+ int* end() { return finish + 1; } // expected-warning{{Returned pointer value points outside the original object}}
+ // expected-note at -1{{Returned pointer value points outside the original object}}
+ // expected-note at -2{{Original object 'buffer' is an array of 20 'int' objects, returned pointer points at index 21}}
};
void use_bad_iterable_object() {
- BadIterable<20> iter;
- iter.end();
+ BadIterable<20> iter; // expected-note{{Calling default constructor for 'BadIterable<20>'}}
+ // expected-note at -1{{Returning from default constructor for 'BadIterable<20>'}}
+ iter.end(); // expected-note{{Calling 'BadIterable::end'}}
}
+
+int *test_idx_sym(int I) {
+ static int arr[10]; // expected-note{{Original object declared here}} expected-note{{'arr' initialized here}}
+
+ if (I != 11) // expected-note{{Assuming 'I' is equal to 11}}
+ // expected-note at -1{{Taking false branch}}
+ return arr;
+ return arr + I; // expected-warning{{Returned pointer value points outside the original object}}
+ // expected-note at -1{{Returned pointer value points outside the original object}}
+ // expected-note at -2{{Original object 'arr' is an array of 10 'int' objects, returned pointer points at index 11}}
+}
+
+namespace test_array_of_struct {
+
+struct Data {
+ int A;
+ char *B;
+};
+
+Data DataArr[10]; // expected-note{{Original object declared here}}
+
+Data *test_struct_array() {
+ int I = conjure_index();
+ if (I != 11) // expected-note{{Assuming 'I' is equal to 11}}
+ // expected-note at -1{{Taking false branch}}
+ return DataArr;
+ return DataArr + I; // expected-warning{{Returned pointer value points outside the original object}}
+ // expected-note at -1{{Returned pointer value points outside the original object}}
+ // expected-note at -2{{Original object 'DataArr' is an array of 10 'test_array_of_struct::Data' objects, returned pointer points at index 11}}
+}
+
+}
+
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