OikawaKirie updated this revision to Diff 532372.
OikawaKirie edited the summary of this revision.
OikawaKirie added a comment.
Update the implementation of InvalidateBuffer in a multi-entrance-with-callback
manner.
Update test cases as suggested.
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D152435/new/
https://reviews.llvm.org/D152435
Files:
clang/lib/StaticAnalyzer/Checkers/CStringChecker.cpp
clang/test/Analysis/Inputs/system-header-simulator.h
clang/test/Analysis/issue-55019.cpp
clang/test/Analysis/pr22954.c
Index: clang/test/Analysis/pr22954.c
===================================================================
--- clang/test/Analysis/pr22954.c
+++ clang/test/Analysis/pr22954.c
@@ -557,11 +557,12 @@
char input[] = {'a', 'b', 'c', 'd'};
memcpy(x263.s1, input, *(len + n));
clang_analyzer_eval(x263.s1[0] == 0); // expected-warning{{UNKNOWN}}
+ // expected-warning@-1{{Potential leak of memory pointed to by 'x263.s2'}}
clang_analyzer_eval(x263.s1[1] == 0); // expected-warning{{UNKNOWN}}
clang_analyzer_eval(x263.s1[2] == 0); // expected-warning{{UNKNOWN}}
clang_analyzer_eval(x263.s1[3] == 0); // expected-warning{{UNKNOWN}}
clang_analyzer_eval(x263.s2 == 0); // expected-warning{{UNKNOWN}}
- return 0; // expected-warning{{Potential leak of memory pointed to by 'x263.s2'}}
+ return 0;
}
Index: clang/test/Analysis/issue-55019.cpp
===================================================================
--- /dev/null
+++ clang/test/Analysis/issue-55019.cpp
@@ -0,0 +1,89 @@
+// Refer issue 55019 for more details.
+// A supplemental test case of pr22954.c for other functions modeled in
+// the CStringChecker.
+
+// RUN: %clang_analyze_cc1 %s -verify \
+// RUN: -analyzer-checker=core \
+// RUN: -analyzer-checker=unix \
+// RUN: -analyzer-checker=debug.ExprInspection
+
+#include "Inputs/system-header-simulator.h"
+#include "Inputs/system-header-simulator-cxx.h"
+
+void *malloc(size_t);
+void free(void *);
+
+struct mystruct {
+ void *ptr;
+ char arr[4];
+};
+
+void clang_analyzer_dump(const void *);
+
+// CStringChecker::memsetAux
+void fmemset() {
+ mystruct x;
+ x.ptr = malloc(1);
+ clang_analyzer_dump(x.ptr); // expected-warning {{HeapSymRegion}}
+ memset(x.arr, 0, sizeof(x.arr));
+ clang_analyzer_dump(x.ptr); // expected-warning {{HeapSymRegion}}
+ free(x.ptr); // no-leak-warning
+}
+
+// CStringChecker::evalCopyCommon
+void fmemcpy() {
+ mystruct x;
+ x.ptr = malloc(1);
+ clang_analyzer_dump(x.ptr); // expected-warning {{HeapSymRegion}}
+ memcpy(x.arr, "hi", 2);
+ clang_analyzer_dump(x.ptr); // expected-warning {{HeapSymRegion}}
+ free(x.ptr); // no-leak-warning
+}
+
+// CStringChecker::evalStrcpyCommon
+void fstrcpy() {
+ mystruct x;
+ x.ptr = malloc(1);
+ clang_analyzer_dump(x.ptr); // expected-warning {{HeapSymRegion}}
+ strcpy(x.arr, "hi");
+ clang_analyzer_dump(x.ptr); // expected-warning {{HeapSymRegion}}
+ free(x.ptr); // no-leak-warning
+}
+
+void fstrncpy() {
+ mystruct x;
+ x.ptr = malloc(1);
+ clang_analyzer_dump(x.ptr); // expected-warning {{HeapSymRegion}}
+ strncpy(x.arr, "hi", sizeof(x.arr));
+ clang_analyzer_dump(x.ptr); // expected-warning {{HeapSymRegion}}
+ free(x.ptr); // no-leak-warning
+}
+
+// CStringChecker::evalStrsep
+void fstrsep() {
+ mystruct x;
+ x.ptr = malloc(1);
+ clang_analyzer_dump(x.ptr); // expected-warning {{HeapSymRegion}}
+ char *p = x.arr;
+ (void)strsep(&p, "x");
+ clang_analyzer_dump(x.ptr); // expected-warning {{HeapSymRegion}}
+ free(x.ptr); // no-leak-warning
+}
+
+// CStringChecker::evalStdCopyCommon
+void fstdcopy() {
+ mystruct x;
+ x.ptr = new char;
+ clang_analyzer_dump(x.ptr); // expected-warning {{HeapSymRegion}}
+
+ const char *p = "x";
+ std::copy(p, p + 1, x.arr);
+
+ // FIXME: As we currently cannot know whether the copy overflows, the checker
+ // invalidates the entire `x` object. When the copy size through iterators
+ // can be correctly modeled, we can then update the verify direction from
+ // SymRegion to HeapSymRegion as this std::copy call never overflows and
+ // hence the pointer `x.ptr` shall not be invalidated.
+ clang_analyzer_dump(x.ptr); // expected-warning {{SymRegion}}
+ delete static_cast<char*>(x.ptr); // no-leak-warning
+}
Index: clang/test/Analysis/Inputs/system-header-simulator.h
===================================================================
--- clang/test/Analysis/Inputs/system-header-simulator.h
+++ clang/test/Analysis/Inputs/system-header-simulator.h
@@ -63,7 +63,9 @@
char *strcpy(char *restrict, const char *restrict);
char *strncpy(char *dst, const char *src, size_t n);
+char *strsep(char **stringp, const char *delim);
void *memcpy(void *dst, const void *src, size_t n);
+void *memset(void *s, int c, size_t n);
typedef unsigned long __darwin_pthread_key_t;
typedef __darwin_pthread_key_t pthread_key_t;
Index: clang/lib/StaticAnalyzer/Checkers/CStringChecker.cpp
===================================================================
--- clang/lib/StaticAnalyzer/Checkers/CStringChecker.cpp
+++ clang/lib/StaticAnalyzer/Checkers/CStringChecker.cpp
@@ -260,11 +260,31 @@
const Expr *expr,
SVal val) const;
- static ProgramStateRef InvalidateBuffer(CheckerContext &C,
- ProgramStateRef state,
- const Expr *Ex, SVal V,
- bool IsSourceBuffer,
- const Expr *Size);
+ /// Invalidate the destination buffer determined by characters copied.
+ static ProgramStateRef
+ InvalidateDestinationBufferBySize(CheckerContext &C, ProgramStateRef S,
+ const Expr *BufE, SVal BufV, SVal SizeV,
+ QualType SizeTy);
+
+ /// Operation never overflows, do not invalidate the super region.
+ static ProgramStateRef InvalidateDestinationBufferNeverOverflows(
+ CheckerContext &C, ProgramStateRef S, const Expr *BufE, SVal BufV);
+
+ /// We do not know whether the operation can overflow (e.g. size is unknown),
+ /// invalidate the super region and escape related pointers.
+ static ProgramStateRef InvalidateDestinationBufferAlwaysEscapeSuperRegion(
+ CheckerContext &C, ProgramStateRef S, const Expr *BufE, SVal BufV);
+
+ /// Invalidate the source buffer for escaping pointers.
+ static ProgramStateRef InvalidateSourceBuffer(CheckerContext &C,
+ ProgramStateRef S,
+ const Expr *BufE, SVal BufV);
+
+ static ProgramStateRef
+ InvalidateBufferAux(CheckerContext &C, ProgramStateRef state, const Expr *Ex,
+ SVal V,
+ std::function<bool(RegionAndSymbolInvalidationTraits &,
+ const MemRegion *)>);
static bool SummarizeRegion(raw_ostream &os, ASTContext &Ctx,
const MemRegion *MR);
@@ -310,10 +330,9 @@
// Return true if the destination buffer of the copy function may be in bound.
// Expects SVal of Size to be positive and unsigned.
// Expects SVal of FirstBuf to be a FieldRegion.
- static bool IsFirstBufInBound(CheckerContext &C,
- ProgramStateRef state,
- const Expr *FirstBuf,
- const Expr *Size);
+ static bool IsFirstBufInBound(CheckerContext &C, ProgramStateRef state,
+ SVal BufVal, QualType BufTy, SVal LengthVal,
+ QualType LengthTy);
};
} //end anonymous namespace
@@ -967,37 +986,35 @@
return strRegion->getStringLiteral();
}
-bool CStringChecker::IsFirstBufInBound(CheckerContext &C,
- ProgramStateRef state,
- const Expr *FirstBuf,
- const Expr *Size) {
+bool CStringChecker::IsFirstBufInBound(CheckerContext &C, ProgramStateRef state,
+ SVal BufVal, QualType BufTy,
+ SVal LengthVal, QualType LengthTy) {
// If we do not know that the buffer is long enough we return 'true'.
// Otherwise the parent region of this field region would also get
// invalidated, which would lead to warnings based on an unknown state.
+ if (LengthVal.isUnknown())
+ return false;
+
// Originally copied from CheckBufferAccess and CheckLocation.
SValBuilder &svalBuilder = C.getSValBuilder();
ASTContext &Ctx = svalBuilder.getContext();
- const LocationContext *LCtx = C.getLocationContext();
- QualType sizeTy = Size->getType();
QualType PtrTy = Ctx.getPointerType(Ctx.CharTy);
- SVal BufVal = state->getSVal(FirstBuf, LCtx);
- SVal LengthVal = state->getSVal(Size, LCtx);
std::optional<NonLoc> Length = LengthVal.getAs<NonLoc>();
if (!Length)
return true; // cf top comment.
// Compute the offset of the last element to be accessed: size-1.
- NonLoc One = svalBuilder.makeIntVal(1, sizeTy).castAs<NonLoc>();
- SVal Offset = svalBuilder.evalBinOpNN(state, BO_Sub, *Length, One, sizeTy);
+ NonLoc One = svalBuilder.makeIntVal(1, LengthTy).castAs<NonLoc>();
+ SVal Offset = svalBuilder.evalBinOpNN(state, BO_Sub, *Length, One, LengthTy);
if (Offset.isUnknown())
return true; // cf top comment
NonLoc LastOffset = Offset.castAs<NonLoc>();
// Check that the first buffer is sufficiently long.
- SVal BufStart = svalBuilder.evalCast(BufVal, PtrTy, FirstBuf->getType());
+ SVal BufStart = svalBuilder.evalCast(BufVal, PtrTy, BufTy);
std::optional<Loc> BufLoc = BufStart.getAs<Loc>();
if (!BufLoc)
return true; // cf top comment.
@@ -1031,11 +1048,68 @@
return static_cast<bool>(StInBound);
}
-ProgramStateRef CStringChecker::InvalidateBuffer(CheckerContext &C,
- ProgramStateRef state,
- const Expr *E, SVal V,
- bool IsSourceBuffer,
- const Expr *Size) {
+ProgramStateRef CStringChecker::InvalidateDestinationBufferBySize(
+ CheckerContext &C, ProgramStateRef S, const Expr *BufE, SVal BufV,
+ SVal SizeV, QualType SizeTy) {
+ return InvalidateBufferAux(
+ C, S, BufE, BufV,
+ [&C, S, BufTy = BufE->getType(), BufV, SizeV,
+ SizeTy](RegionAndSymbolInvalidationTraits &ITraits, const MemRegion *R) {
+ // If destination buffer is a field region and access is in bound, do
+ // not invalidate its super region.
+ if (MemRegion::FieldRegionKind == R->getKind() &&
+ IsFirstBufInBound(C, S, BufV, BufTy, SizeV, SizeTy)) {
+ ITraits.setTrait(
+ R,
+ RegionAndSymbolInvalidationTraits::TK_DoNotInvalidateSuperRegion);
+ }
+ return false;
+ });
+}
+
+ProgramStateRef
+CStringChecker::InvalidateDestinationBufferAlwaysEscapeSuperRegion(
+ CheckerContext &C, ProgramStateRef S, const Expr *BufE, SVal BufV) {
+ return InvalidateBufferAux(
+ C, S, BufE, BufV,
+ [](RegionAndSymbolInvalidationTraits &, const MemRegion *R) {
+ return MemRegion::FieldRegionKind == R->getKind();
+ });
+}
+
+ProgramStateRef CStringChecker::InvalidateDestinationBufferNeverOverflows(
+ CheckerContext &C, ProgramStateRef S, const Expr *BufE, SVal BufV) {
+ return InvalidateBufferAux(
+ C, S, BufE, BufV,
+ [](RegionAndSymbolInvalidationTraits &ITraits, const MemRegion *R) {
+ if (MemRegion::FieldRegionKind == R->getKind())
+ ITraits.setTrait(
+ R,
+ RegionAndSymbolInvalidationTraits::TK_DoNotInvalidateSuperRegion);
+ return false;
+ });
+}
+
+ProgramStateRef CStringChecker::InvalidateSourceBuffer(CheckerContext &C,
+ ProgramStateRef S,
+ const Expr *BufE,
+ SVal BufV) {
+ return InvalidateBufferAux(
+ C, S, BufE, BufV,
+ [](RegionAndSymbolInvalidationTraits &ITraits, const MemRegion *R) {
+ ITraits.setTrait(
+ R->getBaseRegion(),
+ RegionAndSymbolInvalidationTraits::TK_PreserveContents);
+ ITraits.setTrait(R,
+ RegionAndSymbolInvalidationTraits::TK_SuppressEscape);
+ return true;
+ });
+}
+
+ProgramStateRef CStringChecker::InvalidateBufferAux(
+ CheckerContext &C, ProgramStateRef state, const Expr *E, SVal V,
+ std::function<bool(RegionAndSymbolInvalidationTraits &, const MemRegion *)>
+ SetRegionAndSymbolInvalidationTraits) {
std::optional<Loc> L = V.getAs<Loc>();
if (!L)
return state;
@@ -1055,27 +1129,8 @@
// Invalidate this region.
const LocationContext *LCtx = C.getPredecessor()->getLocationContext();
-
- bool CausesPointerEscape = false;
RegionAndSymbolInvalidationTraits ITraits;
- // Invalidate and escape only indirect regions accessible through the source
- // buffer.
- if (IsSourceBuffer) {
- ITraits.setTrait(R->getBaseRegion(),
- RegionAndSymbolInvalidationTraits::TK_PreserveContents);
- ITraits.setTrait(R, RegionAndSymbolInvalidationTraits::TK_SuppressEscape);
- CausesPointerEscape = true;
- } else {
- const MemRegion::Kind& K = R->getKind();
- if (K == MemRegion::FieldRegionKind)
- if (Size && IsFirstBufInBound(C, state, E, Size)) {
- // If destination buffer is a field region and access is in bound,
- // do not invalidate its super region.
- ITraits.setTrait(
- R,
- RegionAndSymbolInvalidationTraits::TK_DoNotInvalidateSuperRegion);
- }
- }
+ bool CausesPointerEscape = SetRegionAndSymbolInvalidationTraits(ITraits, R);
return state->invalidateRegions(R, E, C.blockCount(), LCtx,
CausesPointerEscape, nullptr, nullptr,
@@ -1182,8 +1237,8 @@
} else {
// If the destination buffer's extent is not equal to the value of
// third argument, just invalidate buffer.
- State = InvalidateBuffer(C, State, DstBuffer, MemVal,
- /*IsSourceBuffer*/ false, Size);
+ State = InvalidateDestinationBufferBySize(C, State, DstBuffer, MemVal,
+ SizeVal, Size->getType());
}
if (StateNullChar && !StateNonNullChar) {
@@ -1208,8 +1263,8 @@
} else {
// If the offset is not zero and char value is not concrete, we can do
// nothing but invalidate the buffer.
- State = InvalidateBuffer(C, State, DstBuffer, MemVal,
- /*IsSourceBuffer*/ false, Size);
+ State = InvalidateDestinationBufferBySize(C, State, DstBuffer, MemVal,
+ SizeVal, Size->getType());
}
return true;
}
@@ -1305,15 +1360,14 @@
// can use LazyCompoundVals to copy the source values into the destination.
// This would probably remove any existing bindings past the end of the
// copied region, but that's still an improvement over blank invalidation.
- state =
- InvalidateBuffer(C, state, Dest.Expression, C.getSVal(Dest.Expression),
- /*IsSourceBuffer*/ false, Size.Expression);
+ state = InvalidateDestinationBufferBySize(
+ C, state, Dest.Expression, C.getSVal(Dest.Expression), sizeVal,
+ Size.Expression->getType());
// Invalidate the source (const-invalidation without const-pointer-escaping
// the address of the top-level region).
- state = InvalidateBuffer(C, state, Source.Expression,
- C.getSVal(Source.Expression),
- /*IsSourceBuffer*/ true, nullptr);
+ state = InvalidateSourceBuffer(C, state, Source.Expression,
+ C.getSVal(Source.Expression));
C.addTransition(state);
}
@@ -1985,13 +2039,13 @@
// can use LazyCompoundVals to copy the source values into the destination.
// This would probably remove any existing bindings past the end of the
// string, but that's still an improvement over blank invalidation.
- state = InvalidateBuffer(C, state, Dst.Expression, *dstRegVal,
- /*IsSourceBuffer*/ false, nullptr);
+ state = InvalidateDestinationBufferBySize(C, state, Dst.Expression,
+ *dstRegVal, amountCopied,
+ C.getASTContext().getSizeType());
// Invalidate the source (const-invalidation without const-pointer-escaping
// the address of the top-level region).
- state = InvalidateBuffer(C, state, srcExpr.Expression, srcVal,
- /*IsSourceBuffer*/ true, nullptr);
+ state = InvalidateSourceBuffer(C, state, srcExpr.Expression, srcVal);
// Set the C string length of the destination, if we know it.
if (IsBounded && (appendK == ConcatFnKind::none)) {
@@ -2206,8 +2260,9 @@
// Invalidate the search string, representing the change of one delimiter
// character to NUL.
- State = InvalidateBuffer(C, State, SearchStrPtr.Expression, Result,
- /*IsSourceBuffer*/ false, nullptr);
+ // As the replacement never overflows, do not invalidate its super region.
+ State = InvalidateDestinationBufferNeverOverflows(
+ C, State, SearchStrPtr.Expression, Result);
// Overwrite the search string pointer. The new value is either an address
// further along in the same string, or NULL if there are no more tokens.
@@ -2256,8 +2311,10 @@
// Invalidate the destination buffer
const Expr *Dst = CE->getArg(2);
SVal DstVal = State->getSVal(Dst, LCtx);
- State = InvalidateBuffer(C, State, Dst, DstVal, /*IsSource=*/false,
- /*Size=*/nullptr);
+ // FIXME: As we do not know how many items are copied, we also invalidate the
+ // super region containing the target location.
+ State =
+ InvalidateDestinationBufferAlwaysEscapeSuperRegion(C, State, Dst, DstVal);
SValBuilder &SVB = C.getSValBuilder();
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