[llvm-branch-commits] [clang] Backport fix for crash reported in #88181 (PR #89022)

[Balazs Benics via llvm-branch-commits]

https://github.com/steakhal created https://github.com/llvm/llvm-project/pull/89022

Fixes #88181

(cherry picked from commit e096c144921daba59963f15e89d2ca6fb32d3a78)

The user requested the backport [here](https://github.com/llvm/llvm-project/pull/88536#issuecomment-2052237181).

>From ebe4abe49354d8f42fe403b8d0e6487f0febcf50 Mon Sep 17 00:00:00 2001
From: Balazs Benics <benicsbalazs at gmail.com>
Date: Wed, 17 Apr 2024 08:02:49 +0200
Subject: [PATCH] [analyzer] Fix a security.cert.env.InvalidPtr crash

Fixes #88181

(cherry picked from commit e096c144921daba59963f15e89d2ca6fb32d3a78)
---
 clang/docs/ReleaseNotes.rst                            |  4 ++++
 .../StaticAnalyzer/Checkers/cert/InvalidPtrChecker.cpp |  6 +++++-
 clang/test/Analysis/invalid-ptr-checker.cpp            | 10 ++++++++++
 3 files changed, 19 insertions(+), 1 deletion(-)
 create mode 100644 clang/test/Analysis/invalid-ptr-checker.cpp

diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index ce7e615d878944..1e88b58725bd95 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -1474,6 +1474,10 @@ Crash and bug fixes
 - Fix false positive in mutation check when using pointer to member function.
   (`#66204 <https://github.com/llvm/llvm-project/issues/66204>`_)
 
+- Fixed a crash in ``security.cert.env.InvalidPtr`` checker when accidentally
+  matched user-defined ``strerror`` and similar library functions.
+  (`#88181 <https://github.com/llvm/llvm-project/issues/88181>`_)
+
 Improvements
 ^^^^^^^^^^^^
 
diff --git a/clang/lib/StaticAnalyzer/Checkers/cert/InvalidPtrChecker.cpp b/clang/lib/StaticAnalyzer/Checkers/cert/InvalidPtrChecker.cpp
index e5dd907c660d8e..b2947f590c4ec1 100644
--- a/clang/lib/StaticAnalyzer/Checkers/cert/InvalidPtrChecker.cpp
+++ b/clang/lib/StaticAnalyzer/Checkers/cert/InvalidPtrChecker.cpp
@@ -205,8 +205,12 @@ void InvalidPtrChecker::postPreviousReturnInvalidatingCall(
       CE, LCtx, CE->getType(), C.blockCount());
   State = State->BindExpr(CE, LCtx, RetVal);
 
+  const auto *SymRegOfRetVal =
+      dyn_cast_or_null<SymbolicRegion>(RetVal.getAsRegion());
+  if (!SymRegOfRetVal)
+    return;
+
   // Remember to this region.
-  const auto *SymRegOfRetVal = cast<SymbolicRegion>(RetVal.getAsRegion());
   const MemRegion *MR = SymRegOfRetVal->getBaseRegion();
   State = State->set<PreviousCallResultMap>(FD, MR);
 
diff --git a/clang/test/Analysis/invalid-ptr-checker.cpp b/clang/test/Analysis/invalid-ptr-checker.cpp
new file mode 100644
index 00000000000000..58bb45e0fb8421
--- /dev/null
+++ b/clang/test/Analysis/invalid-ptr-checker.cpp
@@ -0,0 +1,10 @@
+// RUN: %clang_analyze_cc1 -analyzer-checker=core,security.cert.env.InvalidPtr -verify %s
+
+// expected-no-diagnostics
+
+namespace other {
+int strerror(int errnum); // custom strerror
+void no_crash_on_custom_strerror() {
+  (void)strerror(0); // no-crash
+}
+} // namespace other