Add the clang library to the repo (with some of my changes, too).

1 files changed, 786 insertions, 0 deletions

diff --git a/clang/lib/StaticAnalyzer/Checkers/CheckSecuritySyntaxOnly.cpp b/clang/lib/StaticAnalyzer/Checkers/CheckSecuritySyntaxOnly.cpp
new file mode 100644
index 0000000..dde9071
--- /dev/null
+++ b/clang/lib/StaticAnalyzer/Checkers/CheckSecuritySyntaxOnly.cpp
@@ -0,0 +1,786 @@
+//==- CheckSecuritySyntaxOnly.cpp - Basic security checks --------*- C++ -*-==//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+//  This file defines a set of flow-insensitive security checks.
+//
+//===----------------------------------------------------------------------===//
+
+#include "ClangSACheckers.h"
+#include "clang/Analysis/AnalysisContext.h"
+#include "clang/AST/StmtVisitor.h"
+#include "clang/Basic/TargetInfo.h"
+#include "clang/StaticAnalyzer/Core/Checker.h"
+#include "clang/StaticAnalyzer/Core/BugReporter/BugReporter.h"
+#include "clang/StaticAnalyzer/Core/PathSensitive/AnalysisManager.h"
+#include "llvm/ADT/SmallString.h"
+#include "llvm/ADT/StringSwitch.h"
+#include "llvm/Support/raw_ostream.h"
+
+using namespace clang;
+using namespace ento;
+
+static bool isArc4RandomAvailable(const ASTContext &Ctx) {
+  const llvm::Triple &T = Ctx.getTargetInfo().getTriple();
+  return T.getVendor() == llvm::Triple::Apple ||
+         T.getOS() == llvm::Triple::FreeBSD ||
+         T.getOS() == llvm::Triple::NetBSD ||
+         T.getOS() == llvm::Triple::OpenBSD ||
+         T.getOS() == llvm::Triple::DragonFly;
+}
+
+namespace {
+struct DefaultBool {
+  bool val;
+  DefaultBool() : val(false) {}
+  operator bool() const { return val; }
+  DefaultBool &operator=(bool b) { val = b; return *this; }
+};
+  
+struct ChecksFilter {
+  DefaultBool check_gets;
+  DefaultBool check_getpw;
+  DefaultBool check_mktemp;
+  DefaultBool check_mkstemp;
+  DefaultBool check_strcpy;
+  DefaultBool check_rand;
+  DefaultBool check_vfork;
+  DefaultBool check_FloatLoopCounter;
+  DefaultBool check_UncheckedReturn;
+};
+  
+class WalkAST : public StmtVisitor<WalkAST> {
+  BugReporter &BR;
+  AnalysisDeclContext* AC;
+  enum { num_setids = 6 };
+  IdentifierInfo *II_setid[num_setids];
+
+  const bool CheckRand;
+  const ChecksFilter &filter;
+
+public:
+  WalkAST(BugReporter &br, AnalysisDeclContext* ac,
+          const ChecksFilter &f)
+  : BR(br), AC(ac), II_setid(),
+    CheckRand(isArc4RandomAvailable(BR.getContext())),
+    filter(f) {}
+
+  // Statement visitor methods.
+  void VisitCallExpr(CallExpr *CE);
+  void VisitForStmt(ForStmt *S);
+  void VisitCompoundStmt (CompoundStmt *S);
+  void VisitStmt(Stmt *S) { VisitChildren(S); }
+
+  void VisitChildren(Stmt *S);
+
+  // Helpers.
+  bool checkCall_strCommon(const CallExpr *CE, const FunctionDecl *FD);
+
+  typedef void (WalkAST::*FnCheck)(const CallExpr *,
+				   const FunctionDecl *);
+
+  // Checker-specific methods.
+  void checkLoopConditionForFloat(const ForStmt *FS);
+  void checkCall_gets(const CallExpr *CE, const FunctionDecl *FD);
+  void checkCall_getpw(const CallExpr *CE, const FunctionDecl *FD);
+  void checkCall_mktemp(const CallExpr *CE, const FunctionDecl *FD);
+  void checkCall_mkstemp(const CallExpr *CE, const FunctionDecl *FD);
+  void checkCall_strcpy(const CallExpr *CE, const FunctionDecl *FD);
+  void checkCall_strcat(const CallExpr *CE, const FunctionDecl *FD);
+  void checkCall_rand(const CallExpr *CE, const FunctionDecl *FD);
+  void checkCall_random(const CallExpr *CE, const FunctionDecl *FD);
+  void checkCall_vfork(const CallExpr *CE, const FunctionDecl *FD);
+  void checkUncheckedReturnValue(CallExpr *CE);
+};
+} // end anonymous namespace
+
+//===----------------------------------------------------------------------===//
+// AST walking.
+//===----------------------------------------------------------------------===//
+
+void WalkAST::VisitChildren(Stmt *S) {
+  for (Stmt::child_iterator I = S->child_begin(), E = S->child_end(); I!=E; ++I)
+    if (Stmt *child = *I)
+      Visit(child);
+}
+
+void WalkAST::VisitCallExpr(CallExpr *CE) {
+  // Get the callee.  
+  const FunctionDecl *FD = CE->getDirectCallee();
+
+  if (!FD)
+    return;
+
+  // Get the name of the callee. If it's a builtin, strip off the prefix.
+  IdentifierInfo *II = FD->getIdentifier();
+  if (!II)   // if no identifier, not a simple C function
+    return;
+  StringRef Name = II->getName();
+  if (Name.startswith("__builtin_"))
+    Name = Name.substr(10);
+
+  // Set the evaluation function by switching on the callee name.
+  FnCheck evalFunction = llvm::StringSwitch<FnCheck>(Name)
+    .Case("gets", &WalkAST::checkCall_gets)
+    .Case("getpw", &WalkAST::checkCall_getpw)
+    .Case("mktemp", &WalkAST::checkCall_mktemp)
+    .Case("mkstemp", &WalkAST::checkCall_mkstemp)
+    .Case("mkdtemp", &WalkAST::checkCall_mkstemp)
+    .Case("mkstemps", &WalkAST::checkCall_mkstemp)
+    .Cases("strcpy", "__strcpy_chk", &WalkAST::checkCall_strcpy)
+    .Cases("strcat", "__strcat_chk", &WalkAST::checkCall_strcat)
+    .Case("drand48", &WalkAST::checkCall_rand)
+    .Case("erand48", &WalkAST::checkCall_rand)
+    .Case("jrand48", &WalkAST::checkCall_rand)
+    .Case("lrand48", &WalkAST::checkCall_rand)
+    .Case("mrand48", &WalkAST::checkCall_rand)
+    .Case("nrand48", &WalkAST::checkCall_rand)
+    .Case("lcong48", &WalkAST::checkCall_rand)
+    .Case("rand", &WalkAST::checkCall_rand)
+    .Case("rand_r", &WalkAST::checkCall_rand)
+    .Case("random", &WalkAST::checkCall_random)
+    .Case("vfork", &WalkAST::checkCall_vfork)
+    .Default(NULL);
+
+  // If the callee isn't defined, it is not of security concern.
+  // Check and evaluate the call.
+  if (evalFunction)
+    (this->*evalFunction)(CE, FD);
+
+  // Recurse and check children.
+  VisitChildren(CE);
+}
+
+void WalkAST::VisitCompoundStmt(CompoundStmt *S) {
+  for (Stmt::child_iterator I = S->child_begin(), E = S->child_end(); I!=E; ++I)
+    if (Stmt *child = *I) {
+      if (CallExpr *CE = dyn_cast<CallExpr>(child))
+        checkUncheckedReturnValue(CE);
+      Visit(child);
+    }
+}
+
+void WalkAST::VisitForStmt(ForStmt *FS) {
+  checkLoopConditionForFloat(FS);
+
+  // Recurse and check children.
+  VisitChildren(FS);
+}
+
+//===----------------------------------------------------------------------===//
+// Check: floating poing variable used as loop counter.
+// Originally: <rdar://problem/6336718>
+// Implements: CERT security coding advisory FLP-30.
+//===----------------------------------------------------------------------===//
+
+static const DeclRefExpr*
+getIncrementedVar(const Expr *expr, const VarDecl *x, const VarDecl *y) {
+  expr = expr->IgnoreParenCasts();
+
+  if (const BinaryOperator *B = dyn_cast<BinaryOperator>(expr)) {
+    if (!(B->isAssignmentOp() || B->isCompoundAssignmentOp() ||
+          B->getOpcode() == BO_Comma))
+      return NULL;
+
+    if (const DeclRefExpr *lhs = getIncrementedVar(B->getLHS(), x, y))
+      return lhs;
+
+    if (const DeclRefExpr *rhs = getIncrementedVar(B->getRHS(), x, y))
+      return rhs;
+
+    return NULL;
+  }
+
+  if (const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(expr)) {
+    const NamedDecl *ND = DR->getDecl();
+    return ND == x || ND == y ? DR : NULL;
+  }
+
+  if (const UnaryOperator *U = dyn_cast<UnaryOperator>(expr))
+    return U->isIncrementDecrementOp()
+      ? getIncrementedVar(U->getSubExpr(), x, y) : NULL;
+
+  return NULL;
+}
+
+/// CheckLoopConditionForFloat - This check looks for 'for' statements that
+///  use a floating point variable as a loop counter.
+///  CERT: FLP30-C, FLP30-CPP.
+///
+void WalkAST::checkLoopConditionForFloat(const ForStmt *FS) {
+  if (!filter.check_FloatLoopCounter)
+    return;
+
+  // Does the loop have a condition?
+  const Expr *condition = FS->getCond();
+
+  if (!condition)
+    return;
+
+  // Does the loop have an increment?
+  const Expr *increment = FS->getInc();
+
+  if (!increment)
+    return;
+
+  // Strip away '()' and casts.
+  condition = condition->IgnoreParenCasts();
+  increment = increment->IgnoreParenCasts();
+
+  // Is the loop condition a comparison?
+  const BinaryOperator *B = dyn_cast<BinaryOperator>(condition);
+
+  if (!B)
+    return;
+
+  // Is this a comparison?
+  if (!(B->isRelationalOp() || B->isEqualityOp()))
+    return;
+
+  // Are we comparing variables?
+  const DeclRefExpr *drLHS =
+    dyn_cast<DeclRefExpr>(B->getLHS()->IgnoreParenLValueCasts());
+  const DeclRefExpr *drRHS =
+    dyn_cast<DeclRefExpr>(B->getRHS()->IgnoreParenLValueCasts());
+
+  // Does at least one of the variables have a floating point type?
+  drLHS = drLHS && drLHS->getType()->isRealFloatingType() ? drLHS : NULL;
+  drRHS = drRHS && drRHS->getType()->isRealFloatingType() ? drRHS : NULL;
+
+  if (!drLHS && !drRHS)
+    return;
+
+  const VarDecl *vdLHS = drLHS ? dyn_cast<VarDecl>(drLHS->getDecl()) : NULL;
+  const VarDecl *vdRHS = drRHS ? dyn_cast<VarDecl>(drRHS->getDecl()) : NULL;
+
+  if (!vdLHS && !vdRHS)
+    return;
+
+  // Does either variable appear in increment?
+  const DeclRefExpr *drInc = getIncrementedVar(increment, vdLHS, vdRHS);
+
+  if (!drInc)
+    return;
+
+  // Emit the error.  First figure out which DeclRefExpr in the condition
+  // referenced the compared variable.
+  const DeclRefExpr *drCond = vdLHS == drInc->getDecl() ? drLHS : drRHS;
+
+  SmallVector<SourceRange, 2> ranges;
+  SmallString<256> sbuf;
+  llvm::raw_svector_ostream os(sbuf);
+
+  os << "Variable '" << drCond->getDecl()->getName()
+     << "' with floating point type '" << drCond->getType().getAsString()
+     << "' should not be used as a loop counter";
+
+  ranges.push_back(drCond->getSourceRange());
+  ranges.push_back(drInc->getSourceRange());
+
+  const char *bugType = "Floating point variable used as loop counter";
+
+  PathDiagnosticLocation FSLoc =
+    PathDiagnosticLocation::createBegin(FS, BR.getSourceManager(), AC);
+  BR.EmitBasicReport(AC->getDecl(),
+                     bugType, "Security", os.str(),
+                     FSLoc, ranges.data(), ranges.size());
+}
+
+//===----------------------------------------------------------------------===//
+// Check: Any use of 'gets' is insecure.
+// Originally: <rdar://problem/6335715>
+// Implements (part of): 300-BSI (buildsecurityin.us-cert.gov)
+// CWE-242: Use of Inherently Dangerous Function
+//===----------------------------------------------------------------------===//
+
+void WalkAST::checkCall_gets(const CallExpr *CE, const FunctionDecl *FD) {
+  if (!filter.check_gets)
+    return;
+  
+  const FunctionProtoType *FPT
+    = dyn_cast<FunctionProtoType>(FD->getType().IgnoreParens());
+  if (!FPT)
+    return;
+
+  // Verify that the function takes a single argument.
+  if (FPT->getNumArgs() != 1)
+    return;
+
+  // Is the argument a 'char*'?
+  const PointerType *PT = dyn_cast<PointerType>(FPT->getArgType(0));
+  if (!PT)
+    return;
+
+  if (PT->getPointeeType().getUnqualifiedType() != BR.getContext().CharTy)
+    return;
+
+  // Issue a warning.
+  SourceRange R = CE->getCallee()->getSourceRange();
+  PathDiagnosticLocation CELoc =
+    PathDiagnosticLocation::createBegin(CE, BR.getSourceManager(), AC);
+  BR.EmitBasicReport(AC->getDecl(),
+                     "Potential buffer overflow in call to 'gets'",
+                     "Security",
+                     "Call to function 'gets' is extremely insecure as it can "
+                     "always result in a buffer overflow",
+                     CELoc, &R, 1);
+}
+
+//===----------------------------------------------------------------------===//
+// Check: Any use of 'getpwd' is insecure.
+// CWE-477: Use of Obsolete Functions
+//===----------------------------------------------------------------------===//
+
+void WalkAST::checkCall_getpw(const CallExpr *CE, const FunctionDecl *FD) {
+  if (!filter.check_getpw)
+    return;
+
+  const FunctionProtoType *FPT
+    = dyn_cast<FunctionProtoType>(FD->getType().IgnoreParens());
+  if (!FPT)
+    return;
+
+  // Verify that the function takes two arguments.
+  if (FPT->getNumArgs() != 2)
+    return;
+
+  // Verify the first argument type is integer.
+  if (!FPT->getArgType(0)->isIntegerType())
+    return;
+
+  // Verify the second argument type is char*.
+  const PointerType *PT = dyn_cast<PointerType>(FPT->getArgType(1));
+  if (!PT)
+    return;
+
+  if (PT->getPointeeType().getUnqualifiedType() != BR.getContext().CharTy)
+    return;
+
+  // Issue a warning.
+  SourceRange R = CE->getCallee()->getSourceRange();
+  PathDiagnosticLocation CELoc =
+    PathDiagnosticLocation::createBegin(CE, BR.getSourceManager(), AC);
+  BR.EmitBasicReport(AC->getDecl(),
+                     "Potential buffer overflow in call to 'getpw'",
+                     "Security",
+                     "The getpw() function is dangerous as it may overflow the "
+                     "provided buffer. It is obsoleted by getpwuid().",
+                     CELoc, &R, 1);
+}
+
+//===----------------------------------------------------------------------===//
+// Check: Any use of 'mktemp' is insecure.  It is obsoleted by mkstemp().
+// CWE-377: Insecure Temporary File
+//===----------------------------------------------------------------------===//
+
+void WalkAST::checkCall_mktemp(const CallExpr *CE, const FunctionDecl *FD) {
+  if (!filter.check_mktemp) {
+    // Fall back to the security check of looking for enough 'X's in the
+    // format string, since that is a less severe warning.
+    checkCall_mkstemp(CE, FD);
+    return;
+  }
+
+  const FunctionProtoType *FPT
+    = dyn_cast<FunctionProtoType>(FD->getType().IgnoreParens());
+  if(!FPT)
+    return;
+
+  // Verify that the function takes a single argument.
+  if (FPT->getNumArgs() != 1)
+    return;
+
+  // Verify that the argument is Pointer Type.
+  const PointerType *PT = dyn_cast<PointerType>(FPT->getArgType(0));
+  if (!PT)
+    return;
+
+  // Verify that the argument is a 'char*'.
+  if (PT->getPointeeType().getUnqualifiedType() != BR.getContext().CharTy)
+    return;
+
+  // Issue a waring.
+  SourceRange R = CE->getCallee()->getSourceRange();
+  PathDiagnosticLocation CELoc =
+    PathDiagnosticLocation::createBegin(CE, BR.getSourceManager(), AC);
+  BR.EmitBasicReport(AC->getDecl(),
+                     "Potential insecure temporary file in call 'mktemp'",
+                     "Security",
+                     "Call to function 'mktemp' is insecure as it always "
+                     "creates or uses insecure temporary file.  Use 'mkstemp' "
+                     "instead",
+                     CELoc, &R, 1);
+}
+
+
+//===----------------------------------------------------------------------===//
+// Check: Use of 'mkstemp', 'mktemp', 'mkdtemp' should contain at least 6 X's.
+//===----------------------------------------------------------------------===//
+
+void WalkAST::checkCall_mkstemp(const CallExpr *CE, const FunctionDecl *FD) {
+  if (!filter.check_mkstemp)
+    return;
+
+  StringRef Name = FD->getIdentifier()->getName();
+  std::pair<signed, signed> ArgSuffix =
+    llvm::StringSwitch<std::pair<signed, signed> >(Name)
+      .Case("mktemp", std::make_pair(0,-1))
+      .Case("mkstemp", std::make_pair(0,-1))
+      .Case("mkdtemp", std::make_pair(0,-1))
+      .Case("mkstemps", std::make_pair(0,1))
+      .Default(std::make_pair(-1, -1));
+  
+  assert(ArgSuffix.first >= 0 && "Unsupported function");
+
+  // Check if the number of arguments is consistent with out expectations.
+  unsigned numArgs = CE->getNumArgs();
+  if ((signed) numArgs <= ArgSuffix.first)
+    return;
+  
+  const StringLiteral *strArg =
+    dyn_cast<StringLiteral>(CE->getArg((unsigned)ArgSuffix.first)
+                              ->IgnoreParenImpCasts());
+  
+  // Currently we only handle string literals.  It is possible to do better,
+  // either by looking at references to const variables, or by doing real
+  // flow analysis.
+  if (!strArg || strArg->getCharByteWidth() != 1)
+    return;
+
+  // Count the number of X's, taking into account a possible cutoff suffix.
+  StringRef str = strArg->getString();
+  unsigned numX = 0;
+  unsigned n = str.size();
+
+  // Take into account the suffix.
+  unsigned suffix = 0;
+  if (ArgSuffix.second >= 0) {
+    const Expr *suffixEx = CE->getArg((unsigned)ArgSuffix.second);
+    llvm::APSInt Result;
+    if (!suffixEx->EvaluateAsInt(Result, BR.getContext()))
+      return;
+    // FIXME: Issue a warning.
+    if (Result.isNegative())
+      return;
+    suffix = (unsigned) Result.getZExtValue();
+    n = (n > suffix) ? n - suffix : 0;
+  }
+  
+  for (unsigned i = 0; i < n; ++i)
+    if (str[i] == 'X') ++numX;
+  
+  if (numX >= 6)
+    return;
+  
+  // Issue a warning.
+  SourceRange R = strArg->getSourceRange();
+  PathDiagnosticLocation CELoc =
+    PathDiagnosticLocation::createBegin(CE, BR.getSourceManager(), AC);
+  SmallString<512> buf;
+  llvm::raw_svector_ostream out(buf);
+  out << "Call to '" << Name << "' should have at least 6 'X's in the"
+    " format string to be secure (" << numX << " 'X'";
+  if (numX != 1)
+    out << 's';
+  out << " seen";
+  if (suffix) {
+    out << ", " << suffix << " character";
+    if (suffix > 1)
+      out << 's';
+    out << " used as a suffix";
+  }
+  out << ')';
+  BR.EmitBasicReport(AC->getDecl(),
+                     "Insecure temporary file creation", "Security",
+                     out.str(), CELoc, &R, 1);
+}
+
+//===----------------------------------------------------------------------===//
+// Check: Any use of 'strcpy' is insecure.
+//
+// CWE-119: Improper Restriction of Operations within 
+// the Bounds of a Memory Buffer 
+//===----------------------------------------------------------------------===//
+void WalkAST::checkCall_strcpy(const CallExpr *CE, const FunctionDecl *FD) {
+  if (!filter.check_strcpy)
+    return;
+  
+  if (!checkCall_strCommon(CE, FD))
+    return;
+
+  // Issue a warning.
+  SourceRange R = CE->getCallee()->getSourceRange();
+  PathDiagnosticLocation CELoc =
+    PathDiagnosticLocation::createBegin(CE, BR.getSourceManager(), AC);
+  BR.EmitBasicReport(AC->getDecl(),
+                     "Potential insecure memory buffer bounds restriction in "
+                     "call 'strcpy'",
+                     "Security",
+                     "Call to function 'strcpy' is insecure as it does not "
+                     "provide bounding of the memory buffer. Replace "
+                     "unbounded copy functions with analogous functions that "
+                     "support length arguments such as 'strlcpy'. CWE-119.",
+                     CELoc, &R, 1);
+}
+
+//===----------------------------------------------------------------------===//
+// Check: Any use of 'strcat' is insecure.
+//
+// CWE-119: Improper Restriction of Operations within 
+// the Bounds of a Memory Buffer 
+//===----------------------------------------------------------------------===//
+void WalkAST::checkCall_strcat(const CallExpr *CE, const FunctionDecl *FD) {
+  if (!filter.check_strcpy)
+    return;
+
+  if (!checkCall_strCommon(CE, FD))
+    return;
+
+  // Issue a warning.
+  SourceRange R = CE->getCallee()->getSourceRange();
+  PathDiagnosticLocation CELoc =
+    PathDiagnosticLocation::createBegin(CE, BR.getSourceManager(), AC);
+  BR.EmitBasicReport(AC->getDecl(),
+                     "Potential insecure memory buffer bounds restriction in "
+                     "call 'strcat'",
+                     "Security",
+                     "Call to function 'strcat' is insecure as it does not "
+                     "provide bounding of the memory buffer. Replace "
+                     "unbounded copy functions with analogous functions that "
+                     "support length arguments such as 'strlcat'. CWE-119.",
+                     CELoc, &R, 1);
+}
+
+//===----------------------------------------------------------------------===//
+// Common check for str* functions with no bounds parameters.
+//===----------------------------------------------------------------------===//
+bool WalkAST::checkCall_strCommon(const CallExpr *CE, const FunctionDecl *FD) {
+  const FunctionProtoType *FPT
+    = dyn_cast<FunctionProtoType>(FD->getType().IgnoreParens());
+  if (!FPT)
+    return false;
+
+  // Verify the function takes two arguments, three in the _chk version.
+  int numArgs = FPT->getNumArgs();
+  if (numArgs != 2 && numArgs != 3)
+    return false;
+
+  // Verify the type for both arguments.
+  for (int i = 0; i < 2; i++) {
+    // Verify that the arguments are pointers.
+    const PointerType *PT = dyn_cast<PointerType>(FPT->getArgType(i));
+    if (!PT)
+      return false;
+
+    // Verify that the argument is a 'char*'.
+    if (PT->getPointeeType().getUnqualifiedType() != BR.getContext().CharTy)
+      return false;
+  }
+
+  return true;
+}
+
+//===----------------------------------------------------------------------===//
+// Check: Linear congruent random number generators should not be used
+// Originally: <rdar://problem/63371000>
+// CWE-338: Use of cryptographically weak prng
+//===----------------------------------------------------------------------===//
+
+void WalkAST::checkCall_rand(const CallExpr *CE, const FunctionDecl *FD) {
+  if (!filter.check_rand || !CheckRand)
+    return;
+
+  const FunctionProtoType *FTP
+    = dyn_cast<FunctionProtoType>(FD->getType().IgnoreParens());
+  if (!FTP)
+    return;
+
+  if (FTP->getNumArgs() == 1) {
+    // Is the argument an 'unsigned short *'?
+    // (Actually any integer type is allowed.)
+    const PointerType *PT = dyn_cast<PointerType>(FTP->getArgType(0));
+    if (!PT)
+      return;
+
+    if (! PT->getPointeeType()->isIntegerType())
+      return;
+  }
+  else if (FTP->getNumArgs() != 0)
+    return;
+
+  // Issue a warning.
+  SmallString<256> buf1;
+  llvm::raw_svector_ostream os1(buf1);
+  os1 << '\'' << *FD << "' is a poor random number generator";
+
+  SmallString<256> buf2;
+  llvm::raw_svector_ostream os2(buf2);
+  os2 << "Function '" << *FD
+      << "' is obsolete because it implements a poor random number generator."
+      << "  Use 'arc4random' instead";
+
+  SourceRange R = CE->getCallee()->getSourceRange();
+  PathDiagnosticLocation CELoc =
+    PathDiagnosticLocation::createBegin(CE, BR.getSourceManager(), AC);
+  BR.EmitBasicReport(AC->getDecl(), os1.str(), "Security", os2.str(),
+                     CELoc, &R, 1);
+}
+
+//===----------------------------------------------------------------------===//
+// Check: 'random' should not be used
+// Originally: <rdar://problem/63371000>
+//===----------------------------------------------------------------------===//
+
+void WalkAST::checkCall_random(const CallExpr *CE, const FunctionDecl *FD) {
+  if (!CheckRand || !filter.check_rand)
+    return;
+
+  const FunctionProtoType *FTP
+    = dyn_cast<FunctionProtoType>(FD->getType().IgnoreParens());
+  if (!FTP)
+    return;
+
+  // Verify that the function takes no argument.
+  if (FTP->getNumArgs() != 0)
+    return;
+
+  // Issue a warning.
+  SourceRange R = CE->getCallee()->getSourceRange();
+  PathDiagnosticLocation CELoc =
+    PathDiagnosticLocation::createBegin(CE, BR.getSourceManager(), AC);
+  BR.EmitBasicReport(AC->getDecl(),
+                     "'random' is not a secure random number generator",
+                     "Security",
+                     "The 'random' function produces a sequence of values that "
+                     "an adversary may be able to predict.  Use 'arc4random' "
+                     "instead", CELoc, &R, 1);
+}
+
+//===----------------------------------------------------------------------===//
+// Check: 'vfork' should not be used.
+// POS33-C: Do not use vfork().
+//===----------------------------------------------------------------------===//
+
+void WalkAST::checkCall_vfork(const CallExpr *CE, const FunctionDecl *FD) {
+  if (!filter.check_vfork)
+    return;
+
+  // All calls to vfork() are insecure, issue a warning.
+  SourceRange R = CE->getCallee()->getSourceRange();
+  PathDiagnosticLocation CELoc =
+    PathDiagnosticLocation::createBegin(CE, BR.getSourceManager(), AC);
+  BR.EmitBasicReport(AC->getDecl(),
+                     "Potential insecure implementation-specific behavior in "
+                     "call 'vfork'",
+                     "Security",
+                     "Call to function 'vfork' is insecure as it can lead to "
+                     "denial of service situations in the parent process. "
+                     "Replace calls to vfork with calls to the safer "
+                     "'posix_spawn' function",
+                     CELoc, &R, 1);
+}
+
+//===----------------------------------------------------------------------===//
+// Check: Should check whether privileges are dropped successfully.
+// Originally: <rdar://problem/6337132>
+//===----------------------------------------------------------------------===//
+
+void WalkAST::checkUncheckedReturnValue(CallExpr *CE) {
+  if (!filter.check_UncheckedReturn)
+    return;
+  
+  const FunctionDecl *FD = CE->getDirectCallee();
+  if (!FD)
+    return;
+
+  if (II_setid[0] == NULL) {
+    static const char * const identifiers[num_setids] = {
+      "setuid", "setgid", "seteuid", "setegid",
+      "setreuid", "setregid"
+    };
+
+    for (size_t i = 0; i < num_setids; i++)
+      II_setid[i] = &BR.getContext().Idents.get(identifiers[i]);
+  }
+
+  const IdentifierInfo *id = FD->getIdentifier();
+  size_t identifierid;
+
+  for (identifierid = 0; identifierid < num_setids; identifierid++)
+    if (id == II_setid[identifierid])
+      break;
+
+  if (identifierid >= num_setids)
+    return;
+
+  const FunctionProtoType *FTP
+    = dyn_cast<FunctionProtoType>(FD->getType().IgnoreParens());
+  if (!FTP)
+    return;
+
+  // Verify that the function takes one or two arguments (depending on
+  //   the function).
+  if (FTP->getNumArgs() != (identifierid < 4 ? 1 : 2))
+    return;
+
+  // The arguments must be integers.
+  for (unsigned i = 0; i < FTP->getNumArgs(); i++)
+    if (! FTP->getArgType(i)->isIntegerType())
+      return;
+
+  // Issue a warning.
+  SmallString<256> buf1;
+  llvm::raw_svector_ostream os1(buf1);
+  os1 << "Return value is not checked in call to '" << *FD << '\'';
+
+  SmallString<256> buf2;
+  llvm::raw_svector_ostream os2(buf2);
+  os2 << "The return value from the call to '" << *FD
+      << "' is not checked.  If an error occurs in '" << *FD
+      << "', the following code may execute with unexpected privileges";
+
+  SourceRange R = CE->getCallee()->getSourceRange();
+  PathDiagnosticLocation CELoc =
+    PathDiagnosticLocation::createBegin(CE, BR.getSourceManager(), AC);
+  BR.EmitBasicReport(AC->getDecl(), os1.str(), "Security", os2.str(),
+                     CELoc, &R, 1);
+}
+
+//===----------------------------------------------------------------------===//
+// SecuritySyntaxChecker
+//===----------------------------------------------------------------------===//
+
+namespace {
+class SecuritySyntaxChecker : public Checker<check::ASTCodeBody> {
+public:
+  ChecksFilter filter;
+  
+  void checkASTCodeBody(const Decl *D, AnalysisManager& mgr,
+                        BugReporter &BR) const {
+    WalkAST walker(BR, mgr.getAnalysisDeclContext(D), filter);
+    walker.Visit(D->getBody());
+  }
+};
+}
+
+#define REGISTER_CHECKER(name) \
+void ento::register##name(CheckerManager &mgr) {\
+  mgr.registerChecker<SecuritySyntaxChecker>()->filter.check_##name = true;\
+}
+
+REGISTER_CHECKER(gets)
+REGISTER_CHECKER(getpw)
+REGISTER_CHECKER(mkstemp)
+REGISTER_CHECKER(mktemp)
+REGISTER_CHECKER(strcpy)
+REGISTER_CHECKER(rand)
+REGISTER_CHECKER(vfork)
+REGISTER_CHECKER(FloatLoopCounter)
+REGISTER_CHECKER(UncheckedReturn)
+
+