Vendor import of clang trunk r130700:

http://llvm.org/svn/llvm-project/cfe/trunk@130700
author: dim <dim@FreeBSD.org> 2011-05-02 19:39:53 +0000
committer: dim <dim@FreeBSD.org> 2011-05-02 19:39:53 +0000
commit: 110eaaceddcec790f7e6a5e3bf1261c9aa1e73ab (patch)
tree: 64a10f4c4154739d4a8191d7e1b52ce497f4ebd6 /lib/StaticAnalyzer/Checkers/CheckSecuritySyntaxOnly.cpp
parent: a0fb00f9837bd0d2e5948f16f6a6b82a7a628f51 (diff)
download: FreeBSD-src-110eaaceddcec790f7e6a5e3bf1261c9aa1e73ab.zip
FreeBSD-src-110eaaceddcec790f7e6a5e3bf1261c9aa1e73ab.tar.gz
1 files changed, 144 insertions, 72 deletions
diff --git a/lib/StaticAnalyzer/Checkers/CheckSecuritySyntaxOnly.cpp b/lib/StaticAnalyzer/Checkers/CheckSecuritySyntaxOnly.cpp
index 185520c..53810ee 100644
--- a/lib/StaticAnalyzer/Checkers/CheckSecuritySyntaxOnly.cpp
+++ b/lib/StaticAnalyzer/Checkers/CheckSecuritySyntaxOnly.cpp
@@ -12,11 +12,12 @@
 //===----------------------------------------------------------------------===//
 
 #include "ClangSACheckers.h"
-#include "clang/StaticAnalyzer/Core/CheckerV2.h"
+#include "clang/StaticAnalyzer/Core/Checker.h"
 #include "clang/StaticAnalyzer/Core/BugReporter/BugReporter.h"
 #include "clang/Basic/TargetInfo.h"
 #include "clang/AST/StmtVisitor.h"
 #include "llvm/Support/raw_ostream.h"
+#include "llvm/ADT/StringSwitch.h"
 
 using namespace clang;
 using namespace ento;
@@ -33,21 +34,13 @@ static bool isArc4RandomAvailable(const ASTContext &Ctx) {
 namespace {
 class WalkAST : public StmtVisitor<WalkAST> {
   BugReporter &BR;
-  IdentifierInfo *II_gets;
-  IdentifierInfo *II_getpw;
-  IdentifierInfo *II_mktemp;
-  enum { num_rands = 9 };
-  IdentifierInfo *II_rand[num_rands];
-  IdentifierInfo *II_random;
   enum { num_setids = 6 };
   IdentifierInfo *II_setid[num_setids];
 
   const bool CheckRand;
 
 public:
-  WalkAST(BugReporter &br) : BR(br),
-                             II_gets(0), II_getpw(0), II_mktemp(0),
-                             II_rand(), II_random(0), II_setid(),
+  WalkAST(BugReporter &br) : BR(br), II_setid(),
                  CheckRand(isArc4RandomAvailable(BR.getContext())) {}
 
   // Statement visitor methods.
@@ -59,16 +52,22 @@ public:
   void VisitChildren(Stmt *S);
 
   // Helpers.
-  IdentifierInfo *GetIdentifier(IdentifierInfo *& II, const char *str);
+  IdentifierInfo *getIdentifier(IdentifierInfo *& II, const char *str);
+  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_rand(const CallExpr *CE, const FunctionDecl *FD);
-  void CheckCall_random(const CallExpr *CE, const FunctionDecl *FD);
-  void CheckUncheckedReturnValue(CallExpr *CE);
+  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_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 checkUncheckedReturnValue(CallExpr *CE);
 };
 } // end anonymous namespace
 
@@ -76,7 +75,7 @@ public:
 // Helper methods.
 //===----------------------------------------------------------------------===//
 
-IdentifierInfo *WalkAST::GetIdentifier(IdentifierInfo *& II, const char *str) {
+IdentifierInfo *WalkAST::getIdentifier(IdentifierInfo *& II, const char *str) {
   if (!II)
     II = &BR.getContext().Idents.get(str);
 
@@ -94,15 +93,43 @@ void WalkAST::VisitChildren(Stmt *S) {
 }
 
 void WalkAST::VisitCallExpr(CallExpr *CE) {
-  if (const FunctionDecl *FD = CE->getDirectCallee()) {
-    CheckCall_gets(CE, FD);
-    CheckCall_getpw(CE, FD);
-    CheckCall_mktemp(CE, FD);
-    if (CheckRand) {
-      CheckCall_rand(CE, FD);
-      CheckCall_random(CE, FD);
-    }
-  }
+  // 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;
+  llvm::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)
+    .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)
+    .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);
@@ -112,13 +139,13 @@ 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);
+        checkUncheckedReturnValue(CE);
       Visit(child);
     }
 }
 
 void WalkAST::VisitForStmt(ForStmt *FS) {
-  CheckLoopConditionForFloat(FS);
+  checkLoopConditionForFloat(FS);
 
   // Recurse and check children.
   VisitChildren(FS);
@@ -131,7 +158,7 @@ void WalkAST::VisitForStmt(ForStmt *FS) {
 //===----------------------------------------------------------------------===//
 
 static const DeclRefExpr*
-GetIncrementedVar(const Expr *expr, const VarDecl *x, const VarDecl *y) {
+getIncrementedVar(const Expr *expr, const VarDecl *x, const VarDecl *y) {
   expr = expr->IgnoreParenCasts();
 
   if (const BinaryOperator *B = dyn_cast<BinaryOperator>(expr)) {
@@ -139,10 +166,10 @@ GetIncrementedVar(const Expr *expr, const VarDecl *x, const VarDecl *y) {
           B->getOpcode() == BO_Comma))
       return NULL;
 
-    if (const DeclRefExpr *lhs = GetIncrementedVar(B->getLHS(), x, y))
+    if (const DeclRefExpr *lhs = getIncrementedVar(B->getLHS(), x, y))
       return lhs;
 
-    if (const DeclRefExpr *rhs = GetIncrementedVar(B->getRHS(), x, y))
+    if (const DeclRefExpr *rhs = getIncrementedVar(B->getRHS(), x, y))
       return rhs;
 
     return NULL;
@@ -155,7 +182,7 @@ GetIncrementedVar(const Expr *expr, const VarDecl *x, const VarDecl *y) {
 
   if (const UnaryOperator *U = dyn_cast<UnaryOperator>(expr))
     return U->isIncrementDecrementOp()
-      ? GetIncrementedVar(U->getSubExpr(), x, y) : NULL;
+      ? getIncrementedVar(U->getSubExpr(), x, y) : NULL;
 
   return NULL;
 }
@@ -164,7 +191,7 @@ GetIncrementedVar(const Expr *expr, const VarDecl *x, const VarDecl *y) {
 ///  use a floating point variable as a loop counter.
 ///  CERT: FLP30-C, FLP30-CPP.
 ///
-void WalkAST::CheckLoopConditionForFloat(const ForStmt *FS) {
+void WalkAST::checkLoopConditionForFloat(const ForStmt *FS) {
   // Does the loop have a condition?
   const Expr *condition = FS->getCond();
 
@@ -211,7 +238,7 @@ void WalkAST::CheckLoopConditionForFloat(const ForStmt *FS) {
     return;
 
   // Does either variable appear in increment?
-  const DeclRefExpr *drInc = GetIncrementedVar(increment, vdLHS, vdRHS);
+  const DeclRefExpr *drInc = getIncrementedVar(increment, vdLHS, vdRHS);
 
   if (!drInc)
     return;
@@ -243,10 +270,7 @@ void WalkAST::CheckLoopConditionForFloat(const ForStmt *FS) {
 // CWE-242: Use of Inherently Dangerous Function
 //===----------------------------------------------------------------------===//
 
-void WalkAST::CheckCall_gets(const CallExpr *CE, const FunctionDecl *FD) {
-  if (FD->getIdentifier() != GetIdentifier(II_gets, "gets"))
-    return;
-
+void WalkAST::checkCall_gets(const CallExpr *CE, const FunctionDecl *FD) {
   const FunctionProtoType *FPT
     = dyn_cast<FunctionProtoType>(FD->getType().IgnoreParens());
   if (!FPT)
@@ -278,10 +302,7 @@ void WalkAST::CheckCall_gets(const CallExpr *CE, const FunctionDecl *FD) {
 // CWE-477: Use of Obsolete Functions
 //===----------------------------------------------------------------------===//
 
-void WalkAST::CheckCall_getpw(const CallExpr *CE, const FunctionDecl *FD) {
-  if (FD->getIdentifier() != GetIdentifier(II_getpw, "getpw"))
-    return;
-
+void WalkAST::checkCall_getpw(const CallExpr *CE, const FunctionDecl *FD) {
   const FunctionProtoType *FPT
     = dyn_cast<FunctionProtoType>(FD->getType().IgnoreParens());
   if (!FPT)
@@ -317,16 +338,13 @@ void WalkAST::CheckCall_getpw(const CallExpr *CE, const FunctionDecl *FD) {
 // CWE-377: Insecure Temporary File
 //===----------------------------------------------------------------------===//
 
-void WalkAST::CheckCall_mktemp(const CallExpr *CE, const FunctionDecl *FD) {
-  if (FD->getIdentifier() != GetIdentifier(II_mktemp, "mktemp"))
-    return;
-
+void WalkAST::checkCall_mktemp(const CallExpr *CE, const FunctionDecl *FD) {
   const FunctionProtoType *FPT
     = dyn_cast<FunctionProtoType>(FD->getType().IgnoreParens());
   if(!FPT)
     return;
 
-  // Verify that the funcion takes a single argument.
+  // Verify that the function takes a single argument.
   if (FPT->getNumArgs() != 1)
     return;
 
@@ -349,32 +367,86 @@ void WalkAST::CheckCall_mktemp(const CallExpr *CE, const FunctionDecl *FD) {
 }
 
 //===----------------------------------------------------------------------===//
-// Check: Linear congruent random number generators should not be used
-// Originally: <rdar://problem/63371000>
-// CWE-338: Use of cryptographically weak prng
+// 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 (!checkCall_strCommon(CE, FD))
+    return;
 
-void WalkAST::CheckCall_rand(const CallExpr *CE, const FunctionDecl *FD) {
-  if (II_rand[0] == NULL) {
-    // This check applies to these functions
-    static const char * const identifiers[num_rands] = {
-      "drand48", "erand48", "jrand48", "lrand48", "mrand48", "nrand48",
-      "lcong48",
-      "rand", "rand_r"
-    };
+  // Issue a warning.
+  SourceRange R = CE->getCallee()->getSourceRange();
+  BR.EmitBasicReport("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 'strncpy'. CWE-119.",
+                     CE->getLocStart(), &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 (!checkCall_strCommon(CE, FD))
+    return;
+
+  // Issue a warning.
+  SourceRange R = CE->getCallee()->getSourceRange();
+  BR.EmitBasicReport("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 'strncat'. CWE-119.",
+                     CE->getLocStart(), &R, 1);
+}
 
-    for (size_t i = 0; i < num_rands; i++)
-      II_rand[i] = &BR.getContext().Idents.get(identifiers[i]);
+//===----------------------------------------------------------------------===//
+// 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;
   }
 
-  const IdentifierInfo *id = FD->getIdentifier();
-  size_t identifierid;
+  return true;
+}
 
-  for (identifierid = 0; identifierid < num_rands; identifierid++)
-    if (id == II_rand[identifierid])
-      break;
+//===----------------------------------------------------------------------===//
+// Check: Linear congruent random number generators should not be used
+// Originally: <rdar://problem/63371000>
+// CWE-338: Use of cryptographically weak prng
+//===----------------------------------------------------------------------===//
 
-  if (identifierid >= num_rands)
+void WalkAST::checkCall_rand(const CallExpr *CE, const FunctionDecl *FD) {
+  if (!CheckRand)
     return;
 
   const FunctionProtoType *FTP
@@ -415,8 +487,8 @@ void WalkAST::CheckCall_rand(const CallExpr *CE, const FunctionDecl *FD) {
 // Originally: <rdar://problem/63371000>
 //===----------------------------------------------------------------------===//
 
-void WalkAST::CheckCall_random(const CallExpr *CE, const FunctionDecl *FD) {
-  if (FD->getIdentifier() != GetIdentifier(II_random, "random"))
+void WalkAST::checkCall_random(const CallExpr *CE, const FunctionDecl *FD) {
+  if (!CheckRand)
     return;
 
   const FunctionProtoType *FTP
@@ -442,7 +514,7 @@ void WalkAST::CheckCall_random(const CallExpr *CE, const FunctionDecl *FD) {
 // Originally: <rdar://problem/6337132>
 //===----------------------------------------------------------------------===//
 
-void WalkAST::CheckUncheckedReturnValue(CallExpr *CE) {
+void WalkAST::checkUncheckedReturnValue(CallExpr *CE) {
   const FunctionDecl *FD = CE->getDirectCallee();
   if (!FD)
     return;
@@ -502,7 +574,7 @@ void WalkAST::CheckUncheckedReturnValue(CallExpr *CE) {
 //===----------------------------------------------------------------------===//
 
 namespace {
-class SecuritySyntaxChecker : public CheckerV2<check::ASTCodeBody> {
+class SecuritySyntaxChecker : public Checker<check::ASTCodeBody> {
 public:
   void checkASTCodeBody(const Decl *D, AnalysisManager& mgr,
                         BugReporter &BR) const {
author	dim <dim@FreeBSD.org>	2011-05-02 19:39:53 +0000
committer	dim <dim@FreeBSD.org>	2011-05-02 19:39:53 +0000
commit	110eaaceddcec790f7e6a5e3bf1261c9aa1e73ab (patch)
tree	64a10f4c4154739d4a8191d7e1b52ce497f4ebd6 /lib/StaticAnalyzer/Checkers/CheckSecuritySyntaxOnly.cpp
parent	a0fb00f9837bd0d2e5948f16f6a6b82a7a628f51 (diff)
download	FreeBSD-src-110eaaceddcec790f7e6a5e3bf1261c9aa1e73ab.zip FreeBSD-src-110eaaceddcec790f7e6a5e3bf1261c9aa1e73ab.tar.gz