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-rw-r--r--contrib/llvm/tools/clang/lib/StaticAnalyzer/Checkers/CStringSyntaxChecker.cpp287
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diff --git a/contrib/llvm/tools/clang/lib/StaticAnalyzer/Checkers/CStringSyntaxChecker.cpp b/contrib/llvm/tools/clang/lib/StaticAnalyzer/Checkers/CStringSyntaxChecker.cpp
deleted file mode 100644
index b828ac059236..000000000000
--- a/contrib/llvm/tools/clang/lib/StaticAnalyzer/Checkers/CStringSyntaxChecker.cpp
+++ /dev/null
@@ -1,287 +0,0 @@
-//== CStringSyntaxChecker.cpp - CoreFoundation containers API *- C++ -*-==//
-//
-// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
-// See https://llvm.org/LICENSE.txt for license information.
-// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-//
-//===----------------------------------------------------------------------===//
-//
-// An AST checker that looks for common pitfalls when using C string APIs.
-// - Identifies erroneous patterns in the last argument to strncat - the number
-// of bytes to copy.
-//
-//===----------------------------------------------------------------------===//
-#include "clang/StaticAnalyzer/Checkers/BuiltinCheckerRegistration.h"
-#include "clang/AST/Expr.h"
-#include "clang/AST/OperationKinds.h"
-#include "clang/AST/StmtVisitor.h"
-#include "clang/Analysis/AnalysisDeclContext.h"
-#include "clang/Basic/TargetInfo.h"
-#include "clang/Basic/TypeTraits.h"
-#include "clang/StaticAnalyzer/Core/BugReporter/BugReporter.h"
-#include "clang/StaticAnalyzer/Core/Checker.h"
-#include "clang/StaticAnalyzer/Core/PathSensitive/AnalysisManager.h"
-#include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"
-#include "llvm/ADT/SmallString.h"
-#include "llvm/Support/raw_ostream.h"
-
-using namespace clang;
-using namespace ento;
-
-namespace {
-class WalkAST: public StmtVisitor<WalkAST> {
- const CheckerBase *Checker;
- BugReporter &BR;
- AnalysisDeclContext* AC;
-
- /// Check if two expressions refer to the same declaration.
- bool sameDecl(const Expr *A1, const Expr *A2) {
- if (const auto *D1 = dyn_cast<DeclRefExpr>(A1->IgnoreParenCasts()))
- if (const auto *D2 = dyn_cast<DeclRefExpr>(A2->IgnoreParenCasts()))
- return D1->getDecl() == D2->getDecl();
- return false;
- }
-
- /// Check if the expression E is a sizeof(WithArg).
- bool isSizeof(const Expr *E, const Expr *WithArg) {
- if (const auto *UE = dyn_cast<UnaryExprOrTypeTraitExpr>(E))
- if (UE->getKind() == UETT_SizeOf && !UE->isArgumentType())
- return sameDecl(UE->getArgumentExpr(), WithArg);
- return false;
- }
-
- /// Check if the expression E is a strlen(WithArg).
- bool isStrlen(const Expr *E, const Expr *WithArg) {
- if (const auto *CE = dyn_cast<CallExpr>(E)) {
- const FunctionDecl *FD = CE->getDirectCallee();
- if (!FD)
- return false;
- return (CheckerContext::isCLibraryFunction(FD, "strlen") &&
- sameDecl(CE->getArg(0), WithArg));
- }
- return false;
- }
-
- /// Check if the expression is an integer literal with value 1.
- bool isOne(const Expr *E) {
- if (const auto *IL = dyn_cast<IntegerLiteral>(E))
- return (IL->getValue().isIntN(1));
- return false;
- }
-
- StringRef getPrintableName(const Expr *E) {
- if (const auto *D = dyn_cast<DeclRefExpr>(E->IgnoreParenCasts()))
- return D->getDecl()->getName();
- return StringRef();
- }
-
- /// Identify erroneous patterns in the last argument to strncat - the number
- /// of bytes to copy.
- bool containsBadStrncatPattern(const CallExpr *CE);
-
- /// Identify erroneous patterns in the last argument to strlcpy - the number
- /// of bytes to copy.
- /// The bad pattern checked is when the size is known
- /// to be larger than the destination can handle.
- /// char dst[2];
- /// size_t cpy = 4;
- /// strlcpy(dst, "abcd", sizeof("abcd") - 1);
- /// strlcpy(dst, "abcd", 4);
- /// strlcpy(dst + 3, "abcd", 2);
- /// strlcpy(dst, "abcd", cpy);
- /// Identify erroneous patterns in the last argument to strlcat - the number
- /// of bytes to copy.
- /// The bad pattern checked is when the last argument is basically
- /// pointing to the destination buffer size or argument larger or
- /// equal to.
- /// char dst[2];
- /// strlcat(dst, src2, sizeof(dst));
- /// strlcat(dst, src2, 2);
- /// strlcat(dst, src2, 10);
- bool containsBadStrlcpyStrlcatPattern(const CallExpr *CE);
-
-public:
- WalkAST(const CheckerBase *Checker, BugReporter &BR, AnalysisDeclContext *AC)
- : Checker(Checker), BR(BR), AC(AC) {}
-
- // Statement visitor methods.
- void VisitChildren(Stmt *S);
- void VisitStmt(Stmt *S) {
- VisitChildren(S);
- }
- void VisitCallExpr(CallExpr *CE);
-};
-} // end anonymous namespace
-
-// The correct size argument should look like following:
-// strncat(dst, src, sizeof(dst) - strlen(dest) - 1);
-// We look for the following anti-patterns:
-// - strncat(dst, src, sizeof(dst) - strlen(dst));
-// - strncat(dst, src, sizeof(dst) - 1);
-// - strncat(dst, src, sizeof(dst));
-bool WalkAST::containsBadStrncatPattern(const CallExpr *CE) {
- if (CE->getNumArgs() != 3)
- return false;
- const Expr *DstArg = CE->getArg(0);
- const Expr *SrcArg = CE->getArg(1);
- const Expr *LenArg = CE->getArg(2);
-
- // Identify wrong size expressions, which are commonly used instead.
- if (const auto *BE = dyn_cast<BinaryOperator>(LenArg->IgnoreParenCasts())) {
- // - sizeof(dst) - strlen(dst)
- if (BE->getOpcode() == BO_Sub) {
- const Expr *L = BE->getLHS();
- const Expr *R = BE->getRHS();
- if (isSizeof(L, DstArg) && isStrlen(R, DstArg))
- return true;
-
- // - sizeof(dst) - 1
- if (isSizeof(L, DstArg) && isOne(R->IgnoreParenCasts()))
- return true;
- }
- }
- // - sizeof(dst)
- if (isSizeof(LenArg, DstArg))
- return true;
-
- // - sizeof(src)
- if (isSizeof(LenArg, SrcArg))
- return true;
- return false;
-}
-
-bool WalkAST::containsBadStrlcpyStrlcatPattern(const CallExpr *CE) {
- if (CE->getNumArgs() != 3)
- return false;
- const Expr *DstArg = CE->getArg(0);
- const Expr *LenArg = CE->getArg(2);
-
- const auto *DstArgDecl = dyn_cast<DeclRefExpr>(DstArg->IgnoreParenImpCasts());
- const auto *LenArgDecl = dyn_cast<DeclRefExpr>(LenArg->IgnoreParenLValueCasts());
- uint64_t DstOff = 0;
- if (isSizeof(LenArg, DstArg))
- return false;
- // - size_t dstlen = sizeof(dst)
- if (LenArgDecl) {
- const auto *LenArgVal = dyn_cast<VarDecl>(LenArgDecl->getDecl());
- if (LenArgVal->getInit())
- LenArg = LenArgVal->getInit();
- }
-
- // - integral value
- // We try to figure out if the last argument is possibly longer
- // than the destination can possibly handle if its size can be defined.
- if (const auto *IL = dyn_cast<IntegerLiteral>(LenArg->IgnoreParenImpCasts())) {
- uint64_t ILRawVal = IL->getValue().getZExtValue();
-
- // Case when there is pointer arithmetic on the destination buffer
- // especially when we offset from the base decreasing the
- // buffer length accordingly.
- if (!DstArgDecl) {
- if (const auto *BE = dyn_cast<BinaryOperator>(DstArg->IgnoreParenImpCasts())) {
- DstArgDecl = dyn_cast<DeclRefExpr>(BE->getLHS()->IgnoreParenImpCasts());
- if (BE->getOpcode() == BO_Add) {
- if ((IL = dyn_cast<IntegerLiteral>(BE->getRHS()->IgnoreParenImpCasts()))) {
- DstOff = IL->getValue().getZExtValue();
- }
- }
- }
- }
- if (DstArgDecl) {
- if (const auto *Buffer = dyn_cast<ConstantArrayType>(DstArgDecl->getType())) {
- ASTContext &C = BR.getContext();
- uint64_t BufferLen = C.getTypeSize(Buffer) / 8;
- auto RemainingBufferLen = BufferLen - DstOff;
- if (RemainingBufferLen < ILRawVal)
- return true;
- }
- }
- }
-
- return false;
-}
-
-void WalkAST::VisitCallExpr(CallExpr *CE) {
- const FunctionDecl *FD = CE->getDirectCallee();
- if (!FD)
- return;
-
- if (CheckerContext::isCLibraryFunction(FD, "strncat")) {
- if (containsBadStrncatPattern(CE)) {
- const Expr *DstArg = CE->getArg(0);
- const Expr *LenArg = CE->getArg(2);
- PathDiagnosticLocation Loc =
- PathDiagnosticLocation::createBegin(LenArg, BR.getSourceManager(), AC);
-
- StringRef DstName = getPrintableName(DstArg);
-
- SmallString<256> S;
- llvm::raw_svector_ostream os(S);
- os << "Potential buffer overflow. ";
- if (!DstName.empty()) {
- os << "Replace with 'sizeof(" << DstName << ") "
- "- strlen(" << DstName <<") - 1'";
- os << " or u";
- } else
- os << "U";
- os << "se a safer 'strlcat' API";
-
- BR.EmitBasicReport(FD, Checker, "Anti-pattern in the argument",
- "C String API", os.str(), Loc,
- LenArg->getSourceRange());
- }
- } else if (CheckerContext::isCLibraryFunction(FD, "strlcpy") ||
- CheckerContext::isCLibraryFunction(FD, "strlcat")) {
- if (containsBadStrlcpyStrlcatPattern(CE)) {
- const Expr *DstArg = CE->getArg(0);
- const Expr *LenArg = CE->getArg(2);
- PathDiagnosticLocation Loc =
- PathDiagnosticLocation::createBegin(LenArg, BR.getSourceManager(), AC);
-
- StringRef DstName = getPrintableName(DstArg);
-
- SmallString<256> S;
- llvm::raw_svector_ostream os(S);
- os << "The third argument allows to potentially copy more bytes than it should. ";
- os << "Replace with the value ";
- if (!DstName.empty())
- os << "sizeof(" << DstName << ")";
- else
- os << "sizeof(<destination buffer>)";
- os << " or lower";
-
- BR.EmitBasicReport(FD, Checker, "Anti-pattern in the argument",
- "C String API", os.str(), Loc,
- LenArg->getSourceRange());
- }
- }
-
- // Recurse and check children.
- VisitChildren(CE);
-}
-
-void WalkAST::VisitChildren(Stmt *S) {
- for (Stmt *Child : S->children())
- if (Child)
- Visit(Child);
-}
-
-namespace {
-class CStringSyntaxChecker: public Checker<check::ASTCodeBody> {
-public:
-
- void checkASTCodeBody(const Decl *D, AnalysisManager& Mgr,
- BugReporter &BR) const {
- WalkAST walker(this, BR, Mgr.getAnalysisDeclContext(D));
- walker.Visit(D->getBody());
- }
-};
-}
-
-void ento::registerCStringSyntaxChecker(CheckerManager &mgr) {
- mgr.registerChecker<CStringSyntaxChecker>();
-}
-
-bool ento::shouldRegisterCStringSyntaxChecker(const LangOptions &LO) {
- return true;
-}
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