[PATCH] D158953: [analyzer] MmapWriteExecChecker: use getAs instead of castAs

[Ding Fei via Phabricator via cfe-commits]

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MmapWriteExecChecker: use getAs instead of castAs

Fixes https://github.com/llvm/llvm-project/issues/62285


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D158953

Files:
  clang/lib/StaticAnalyzer/Checkers/MmapWriteExecChecker.cpp
  clang/test/Analysis/mmap-writeexec.c


Index: clang/test/Analysis/mmap-writeexec.c
===================================================================
--- clang/test/Analysis/mmap-writeexec.c
+++ clang/test/Analysis/mmap-writeexec.c
@@ -42,3 +42,17 @@
   int m = mprotect(p, 1024, PROT_WRITE | PROT_EXEC); // expected-warning{{Both PROT_WRITE and PROT_EXEC flags are set. This can lead to exploitable memory regions, which could be overwritten with malicious code}}
   (void)m;
 }
+
+// gh62285: no crash on non concrete arg 'prot'
+typedef struct malloc_mmap_2
+{
+  int prot;
+} malloc_mmap_st_2;
+
+int gh62285(int cmd, void *arg2)
+{
+  malloc_mmap_st_2* args2 = arg2;
+  void *buf = ((void*)0);
+  buf = mmap((void*)0, 1, args2->prot, 1, 1, 1);
+  return 0;
+}
Index: clang/lib/StaticAnalyzer/Checkers/MmapWriteExecChecker.cpp
===================================================================
--- clang/lib/StaticAnalyzer/Checkers/MmapWriteExecChecker.cpp
+++ clang/lib/StaticAnalyzer/Checkers/MmapWriteExecChecker.cpp
@@ -48,8 +48,10 @@
                                          CheckerContext &C) const {
   if (matchesAny(Call, MmapFn, MprotectFn)) {
     SVal ProtVal = Call.getArgSVal(2);
-    auto ProtLoc = ProtVal.castAs<nonloc::ConcreteInt>();
-    int64_t Prot = ProtLoc.getValue().getSExtValue();
+    auto ProtLoc = ProtVal.getAs<nonloc::ConcreteInt>();
+    if (!ProtLoc)
+      return;
+    int64_t Prot = ProtLoc->getValue().getSExtValue();
     if (ProtExecOv != ProtExec)
       ProtExec = ProtExecOv;
     if (ProtReadOv != ProtRead)


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