diff --git a/clang/docs/analyzer/developer-docs/DebugChecks.rst b/clang/docs/analyzer/developer-docs/DebugChecks.rst --- a/clang/docs/analyzer/developer-docs/DebugChecks.rst +++ b/clang/docs/analyzer/developer-docs/DebugChecks.rst @@ -275,6 +275,28 @@ See clang_analyzer_denote(). +- ``void clang_analyzer_isTainted(a single argument of any type);`` + + Queries the analyzer whether the expression used as argument is tainted or not. + This is useful in tests, where we don't want to issue warning for all tainted + expressions but only check for certain expressions. + This would help to reduce the *noise* that the `TaintTest` debug checker would + introduce and let you focus on the `expected-warning`s that you really care + about. + + Example usage:: + + int read_integer() { + int n; + clang_analyzer_isTainted(n); // expected-warning{{NO}} + scanf("%d", &n); + clang_analyzer_isTainted(n); // expected-warning{{YES}} + clang_analyzer_isTainted(n + 2); // expected-warning{{YES}} + clang_analyzer_isTainted(n > 0); // expected-warning{{YES}} + int next_tainted_value = n; // no-warning + return n; + } + Statistics ========== diff --git a/clang/lib/StaticAnalyzer/Checkers/ExprInspectionChecker.cpp b/clang/lib/StaticAnalyzer/Checkers/ExprInspectionChecker.cpp --- a/clang/lib/StaticAnalyzer/Checkers/ExprInspectionChecker.cpp +++ b/clang/lib/StaticAnalyzer/Checkers/ExprInspectionChecker.cpp @@ -6,6 +6,7 @@ // //===----------------------------------------------------------------------===// +#include "Taint.h" #include "clang/StaticAnalyzer/Checkers/BuiltinCheckerRegistration.h" #include "clang/StaticAnalyzer/Checkers/SValExplainer.h" #include "clang/StaticAnalyzer/Core/BugReporter/BugType.h" @@ -46,6 +47,7 @@ void analyzerHashDump(const CallExpr *CE, CheckerContext &C) const; void analyzerDenote(const CallExpr *CE, CheckerContext &C) const; void analyzerExpress(const CallExpr *CE, CheckerContext &C) const; + void analyzerIsTainted(const CallExpr *CE, CheckerContext &C) const; typedef void (ExprInspectionChecker::*FnCheck)(const CallExpr *, CheckerContext &C) const; @@ -73,26 +75,34 @@ // These checks should have no effect on the surrounding environment // (globals should not be invalidated, etc), hence the use of evalCall. - FnCheck Handler = llvm::StringSwitch(C.getCalleeName(CE)) - .Case("clang_analyzer_eval", &ExprInspectionChecker::analyzerEval) - .Case("clang_analyzer_checkInlined", - &ExprInspectionChecker::analyzerCheckInlined) - .Case("clang_analyzer_crash", &ExprInspectionChecker::analyzerCrash) - .Case("clang_analyzer_warnIfReached", - &ExprInspectionChecker::analyzerWarnIfReached) - .Case("clang_analyzer_warnOnDeadSymbol", - &ExprInspectionChecker::analyzerWarnOnDeadSymbol) - .StartsWith("clang_analyzer_explain", &ExprInspectionChecker::analyzerExplain) - .StartsWith("clang_analyzer_dump", &ExprInspectionChecker::analyzerDump) - .Case("clang_analyzer_getExtent", &ExprInspectionChecker::analyzerGetExtent) - .Case("clang_analyzer_printState", - &ExprInspectionChecker::analyzerPrintState) - .Case("clang_analyzer_numTimesReached", - &ExprInspectionChecker::analyzerNumTimesReached) - .Case("clang_analyzer_hashDump", &ExprInspectionChecker::analyzerHashDump) - .Case("clang_analyzer_denote", &ExprInspectionChecker::analyzerDenote) - .Case("clang_analyzer_express", &ExprInspectionChecker::analyzerExpress) - .Default(nullptr); + FnCheck Handler = + llvm::StringSwitch(C.getCalleeName(CE)) + .Case("clang_analyzer_eval", &ExprInspectionChecker::analyzerEval) + .Case("clang_analyzer_checkInlined", + &ExprInspectionChecker::analyzerCheckInlined) + .Case("clang_analyzer_crash", &ExprInspectionChecker::analyzerCrash) + .Case("clang_analyzer_warnIfReached", + &ExprInspectionChecker::analyzerWarnIfReached) + .Case("clang_analyzer_warnOnDeadSymbol", + &ExprInspectionChecker::analyzerWarnOnDeadSymbol) + .StartsWith("clang_analyzer_explain", + &ExprInspectionChecker::analyzerExplain) + .StartsWith("clang_analyzer_dump", + &ExprInspectionChecker::analyzerDump) + .Case("clang_analyzer_getExtent", + &ExprInspectionChecker::analyzerGetExtent) + .Case("clang_analyzer_printState", + &ExprInspectionChecker::analyzerPrintState) + .Case("clang_analyzer_numTimesReached", + &ExprInspectionChecker::analyzerNumTimesReached) + .Case("clang_analyzer_hashDump", + &ExprInspectionChecker::analyzerHashDump) + .Case("clang_analyzer_denote", &ExprInspectionChecker::analyzerDenote) + .Case("clang_analyzer_express", + &ExprInspectionChecker::analyzerExpress) + .StartsWith("clang_analyzer_isTainted", + &ExprInspectionChecker::analyzerIsTainted) + .Default(nullptr); if (!Handler) return false; @@ -412,6 +422,17 @@ reportBug(*Str, C); } +void ExprInspectionChecker::analyzerIsTainted(const CallExpr *CE, + CheckerContext &C) const { + if (CE->getNumArgs() != 1) { + reportBug("clang_analyzer_isTainted() requires exactly one argument", C); + return; + } + const bool IsTainted = + taint::isTainted(C.getState(), CE->getArg(0), C.getLocationContext()); + reportBug(IsTainted ? "YES" : "NO", C); +} + void ento::registerExprInspectionChecker(CheckerManager &Mgr) { Mgr.registerChecker(); } diff --git a/clang/test/Analysis/debug-exprinspection-istainted.c b/clang/test/Analysis/debug-exprinspection-istainted.c new file mode 100644 --- /dev/null +++ b/clang/test/Analysis/debug-exprinspection-istainted.c @@ -0,0 +1,27 @@ +// RUN: %clang_analyze_cc1 -verify %s \ +// RUN: -analyzer-checker=core \ +// RUN: -analyzer-checker=debug.ExprInspection \ +// RUN: -analyzer-checker=alpha.security.taint + +int scanf(const char *restrict format, ...); +void clang_analyzer_isTainted(char); +void clang_analyzer_isTainted_any_suffix(char); +void clang_analyzer_isTainted_many_arguments(char, int, int); + +void foo() { + char buf[32] = ""; + clang_analyzer_isTainted(buf[0]); // expected-warning {{NO}} + clang_analyzer_isTainted_any_suffix(buf[0]); // expected-warning {{NO}} + scanf("%s", buf); + clang_analyzer_isTainted(buf[0]); // expected-warning {{YES}} + clang_analyzer_isTainted_any_suffix(buf[0]); // expected-warning {{YES}} + + int tainted_value = buf[0]; // no-warning +} + +void exactly_one_argument_required() { + char buf[32] = ""; + scanf("%s", buf); + clang_analyzer_isTainted_many_arguments(buf[0], 42, 42); + // expected-warning@-1 {{clang_analyzer_isTainted() requires exactly one argument}} +}