Author: Balázs Kéri Date: 2023-05-16T09:28:14+02:00 New Revision: 258c9bebbdfa793493b71db555f5deb5ade499b4
URL: https://github.com/llvm/llvm-project/commit/258c9bebbdfa793493b71db555f5deb5ade499b4 DIFF: https://github.com/llvm/llvm-project/commit/258c9bebbdfa793493b71db555f5deb5ade499b4.diff LOG: [clang][analyzer] Handle special value AT_FDCWD in affected standard functions Some file and directory related functions have an integer file descriptor argument that can be a valid file descriptor or a special value AT_FDCWD. This value is relatively often used in open source projects and is usually defined as a negative number, and the checker reports false warnings (a valid file descriptor is not negative) if this fix is not included. Reviewed By: steakhal Differential Revision: https://reviews.llvm.org/D149160 Added: Modified: clang/lib/StaticAnalyzer/Checkers/StdLibraryFunctionsChecker.cpp clang/test/Analysis/std-c-library-functions-arg-constraints.c Removed: ################################################################################ diff --git a/clang/lib/StaticAnalyzer/Checkers/StdLibraryFunctionsChecker.cpp b/clang/lib/StaticAnalyzer/Checkers/StdLibraryFunctionsChecker.cpp index 4e3ea0934b6f1..ef85d60c658ec 100644 --- a/clang/lib/StaticAnalyzer/Checkers/StdLibraryFunctionsChecker.cpp +++ b/clang/lib/StaticAnalyzer/Checkers/StdLibraryFunctionsChecker.cpp @@ -1392,6 +1392,7 @@ void StdLibraryFunctionsChecker::initFunctionSummaries( SValBuilder &SVB = C.getSValBuilder(); BasicValueFactory &BVF = SVB.getBasicValueFactory(); const ASTContext &ACtx = BVF.getContext(); + Preprocessor &PP = C.getPreprocessor(); // Helper class to lookup a type by its name. class LookupType { @@ -1527,14 +1528,11 @@ void StdLibraryFunctionsChecker::initFunctionSummaries( const RangeInt UCharRangeMax = std::min(BVF.getMaxValue(ACtx.UnsignedCharTy).getLimitedValue(), IntMax); - // The platform dependent value of EOF. - // Try our best to parse this from the Preprocessor, otherwise fallback to -1. - const auto EOFv = [&C]() -> RangeInt { - if (const std::optional<int> OptInt = - tryExpandAsInteger("EOF", C.getPreprocessor())) - return *OptInt; - return -1; - }(); + // Get platform dependent values of some macros. + // Try our best to parse this from the Preprocessor, otherwise fallback to a + // default value (what is found in a library header). + const auto EOFv = tryExpandAsInteger("EOF", PP).value_or(-1); + const auto AT_FDCWDv = tryExpandAsInteger("AT_FDCWD", PP).value_or(-100); // Auxiliary class to aid adding summaries to the summary map. struct AddToFunctionSummaryMap { @@ -1979,6 +1977,12 @@ void StdLibraryFunctionsChecker::initFunctionSummaries( ConstraintSet{ReturnValueCondition(WithinRange, Range(-1, IntMax))}; const auto &ReturnsValidFileDescriptor = ReturnsNonnegative; + auto ValidFileDescriptorOrAtFdcwd = [&](ArgNo ArgN) { + return std::make_shared<RangeConstraint>( + ArgN, WithinRange, Range({AT_FDCWDv, AT_FDCWDv}, {0, IntMax}), + "a valid file descriptor or AT_FDCWD"); + }; + // FILE *fopen(const char *restrict pathname, const char *restrict mode); addToFunctionSummaryMap( "fopen", @@ -2130,6 +2134,7 @@ void StdLibraryFunctionsChecker::initFunctionSummaries( Summary(NoEvalCall) .Case(ReturnsZero, ErrnoMustNotBeChecked) .Case(ReturnsMinusOne, ErrnoNEZeroIrrelevant) + .ArgConstraint(ValidFileDescriptorOrAtFdcwd(ArgNo(0))) .ArgConstraint(NotNull(ArgNo(1)))); // int dup(int fildes); @@ -2207,7 +2212,7 @@ void StdLibraryFunctionsChecker::initFunctionSummaries( .Case(ReturnsZero, ErrnoMustNotBeChecked) .Case(ReturnsMinusOne, ErrnoNEZeroIrrelevant) .ArgConstraint(NotNull(ArgNo(0))) - .ArgConstraint(ArgumentCondition(1, WithinRange, Range(0, IntMax))) + .ArgConstraint(ValidFileDescriptorOrAtFdcwd(ArgNo(1))) .ArgConstraint(NotNull(ArgNo(2)))); // int lockf(int fd, int cmd, off_t len); @@ -2318,6 +2323,7 @@ void StdLibraryFunctionsChecker::initFunctionSummaries( Summary(NoEvalCall) .Case(ReturnsZero, ErrnoMustNotBeChecked) .Case(ReturnsMinusOne, ErrnoNEZeroIrrelevant) + .ArgConstraint(ValidFileDescriptorOrAtFdcwd(ArgNo(0))) .ArgConstraint(NotNull(ArgNo(1)))); std::optional<QualType> Dev_tTy = lookupTy("dev_t"); @@ -2339,6 +2345,7 @@ void StdLibraryFunctionsChecker::initFunctionSummaries( Summary(NoEvalCall) .Case(ReturnsZero, ErrnoMustNotBeChecked) .Case(ReturnsMinusOne, ErrnoNEZeroIrrelevant) + .ArgConstraint(ValidFileDescriptorOrAtFdcwd(ArgNo(0))) .ArgConstraint(NotNull(ArgNo(1)))); // int chmod(const char *path, mode_t mode); @@ -2357,7 +2364,7 @@ void StdLibraryFunctionsChecker::initFunctionSummaries( Summary(NoEvalCall) .Case(ReturnsZero, ErrnoMustNotBeChecked) .Case(ReturnsMinusOne, ErrnoNEZeroIrrelevant) - .ArgConstraint(ArgumentCondition(0, WithinRange, Range(0, IntMax))) + .ArgConstraint(ValidFileDescriptorOrAtFdcwd(ArgNo(0))) .ArgConstraint(NotNull(ArgNo(1)))); // int fchmod(int fildes, mode_t mode); @@ -2381,7 +2388,7 @@ void StdLibraryFunctionsChecker::initFunctionSummaries( Summary(NoEvalCall) .Case(ReturnsZero, ErrnoMustNotBeChecked) .Case(ReturnsMinusOne, ErrnoNEZeroIrrelevant) - .ArgConstraint(ArgumentCondition(0, WithinRange, Range(0, IntMax))) + .ArgConstraint(ValidFileDescriptorOrAtFdcwd(ArgNo(0))) .ArgConstraint(NotNull(ArgNo(1)))); // int chown(const char *path, uid_t owner, gid_t group); @@ -2446,9 +2453,9 @@ void StdLibraryFunctionsChecker::initFunctionSummaries( Summary(NoEvalCall) .Case(ReturnsZero, ErrnoMustNotBeChecked) .Case(ReturnsMinusOne, ErrnoNEZeroIrrelevant) - .ArgConstraint(ArgumentCondition(0, WithinRange, Range(0, IntMax))) + .ArgConstraint(ValidFileDescriptorOrAtFdcwd(ArgNo(0))) .ArgConstraint(NotNull(ArgNo(1))) - .ArgConstraint(ArgumentCondition(2, WithinRange, Range(0, IntMax))) + .ArgConstraint(ValidFileDescriptorOrAtFdcwd(ArgNo(2))) .ArgConstraint(NotNull(ArgNo(3)))); // int unlink(const char *pathname); @@ -2466,7 +2473,7 @@ void StdLibraryFunctionsChecker::initFunctionSummaries( Summary(NoEvalCall) .Case(ReturnsZero, ErrnoMustNotBeChecked) .Case(ReturnsMinusOne, ErrnoNEZeroIrrelevant) - .ArgConstraint(ArgumentCondition(0, WithinRange, Range(0, IntMax))) + .ArgConstraint(ValidFileDescriptorOrAtFdcwd(ArgNo(0))) .ArgConstraint(NotNull(ArgNo(1)))); std::optional<QualType> StructStatTy = lookupTy("stat"); @@ -2515,7 +2522,7 @@ void StdLibraryFunctionsChecker::initFunctionSummaries( Summary(NoEvalCall) .Case(ReturnsZero, ErrnoMustNotBeChecked) .Case(ReturnsMinusOne, ErrnoNEZeroIrrelevant) - .ArgConstraint(ArgumentCondition(0, WithinRange, Range(0, IntMax))) + .ArgConstraint(ValidFileDescriptorOrAtFdcwd(ArgNo(0))) .ArgConstraint(NotNull(ArgNo(1))) .ArgConstraint(NotNull(ArgNo(2)))); @@ -2690,7 +2697,7 @@ void StdLibraryFunctionsChecker::initFunctionSummaries( ReturnValueCondition(WithinRange, Range(0, Ssize_tMax))}, ErrnoMustNotBeChecked) .Case(ReturnsMinusOne, ErrnoNEZeroIrrelevant) - .ArgConstraint(ArgumentCondition(0, WithinRange, Range(0, IntMax))) + .ArgConstraint(ValidFileDescriptorOrAtFdcwd(ArgNo(0))) .ArgConstraint(NotNull(ArgNo(1))) .ArgConstraint(NotNull(ArgNo(2))) .ArgConstraint(BufferSize(/*Buffer=*/ArgNo(2), @@ -2707,7 +2714,9 @@ void StdLibraryFunctionsChecker::initFunctionSummaries( Summary(NoEvalCall) .Case(ReturnsZero, ErrnoMustNotBeChecked) .Case(ReturnsMinusOne, ErrnoNEZeroIrrelevant) + .ArgConstraint(ValidFileDescriptorOrAtFdcwd(ArgNo(0))) .ArgConstraint(NotNull(ArgNo(1))) + .ArgConstraint(ValidFileDescriptorOrAtFdcwd(ArgNo(2))) .ArgConstraint(NotNull(ArgNo(3)))); // char *realpath(const char *restrict file_name, diff --git a/clang/test/Analysis/std-c-library-functions-arg-constraints.c b/clang/test/Analysis/std-c-library-functions-arg-constraints.c index 1d9e3ae688cc7..981318c755e1e 100644 --- a/clang/test/Analysis/std-c-library-functions-arg-constraints.c +++ b/clang/test/Analysis/std-c-library-functions-arg-constraints.c @@ -3,6 +3,7 @@ // RUN: -analyzer-checker=core \ // RUN: -analyzer-checker=apiModeling.StdCLibraryFunctions \ // RUN: -analyzer-checker=alpha.unix.StdCLibraryFunctionArgs \ +// RUN: -analyzer-config apiModeling.StdCLibraryFunctions:ModelPOSIX=true \ // RUN: -analyzer-checker=debug.StdCLibraryFunctionsTester \ // RUN: -analyzer-checker=debug.ExprInspection \ // RUN: -triple x86_64-unknown-linux-gnu \ @@ -13,6 +14,7 @@ // RUN: -analyzer-checker=core \ // RUN: -analyzer-checker=apiModeling.StdCLibraryFunctions \ // RUN: -analyzer-checker=alpha.unix.StdCLibraryFunctionArgs \ +// RUN: -analyzer-config apiModeling.StdCLibraryFunctions:ModelPOSIX=true \ // RUN: -analyzer-checker=debug.StdCLibraryFunctionsTester \ // RUN: -analyzer-checker=debug.ExprInspection \ // RUN: -triple x86_64-unknown-linux-gnu \ @@ -309,3 +311,26 @@ void test_min_buf_size(void) { // bugpath-warning{{The 1st argument to '__buf_size_arg_constraint_concrete' is out of the accepted range; It should be a buffer with size equal to or greater than 10}} \ // bugpath-note{{The 1st argument to '__buf_size_arg_constraint_concrete' is out of the accepted range; It should be a buffer with size equal to or greater than 10}} } + +void test_file_fd_at_functions() { + (void)linkat(-22, "from", AT_FDCWD, "to", 0); // \ + // report-warning{{The 1st argument to 'linkat' is -22 but should be a valid file descriptor or AT_FDCWD}} \ + // bugpath-warning{{The 1st argument to 'linkat' is -22 but should be a valid file descriptor or AT_FDCWD}} \ + // bugpath-note{{The 1st argument to 'linkat' is -22 but should be a valid file descriptor or AT_FDCWD}} + + // no warning for these functions if the AT_FDCWD value is used + (void)linkat(AT_FDCWD, "from", AT_FDCWD, "to", 0); + (void)faccessat(AT_FDCWD, "path", 0, 0); + (void)symlinkat("oldpath", AT_FDCWD, "newpath"); + (void)mkdirat(AT_FDCWD, "path", 0); + (void)mknodat(AT_FDCWD, "path", 0, 0); + (void)fchmodat(AT_FDCWD, "path", 0, 0); + (void)fchownat(AT_FDCWD, "path", 0, 0, 0); + (void)linkat(AT_FDCWD, "oldpath", AT_FDCWD, "newpath", 0); + (void)unlinkat(AT_FDCWD, "newpath", 0); + struct stat St; + (void)fstatat(AT_FDCWD, "newpath", &St, 0); + char Buf[10]; + (void)readlinkat(AT_FDCWD, "newpath", Buf, 10); + (void)renameat(AT_FDCWD, "oldpath", AT_FDCWD, "newpath"); +} _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
