llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT--> @llvm/pr-subscribers-clang Author: Balázs Kéri (balazske) <details> <summary>Changes</summary> Read the 'mmap' flags from macro values and use a better test for the error situation. --- Full diff: https://github.com/llvm/llvm-project/pull/97078.diff 2 Files Affected: - (modified) clang/lib/StaticAnalyzer/Checkers/MmapWriteExecChecker.cpp (+33-16) - (modified) clang/test/Analysis/mmap-writeexec.c (+5-4) ``````````diff diff --git a/clang/lib/StaticAnalyzer/Checkers/MmapWriteExecChecker.cpp b/clang/lib/StaticAnalyzer/Checkers/MmapWriteExecChecker.cpp index cd1dd1b2fc511..a5a2bd62b47d6 100644 --- a/clang/lib/StaticAnalyzer/Checkers/MmapWriteExecChecker.cpp +++ b/clang/lib/StaticAnalyzer/Checkers/MmapWriteExecChecker.cpp @@ -21,30 +21,55 @@ #include "clang/StaticAnalyzer/Core/PathSensitive/CallDescription.h" #include "clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h" #include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h" +#include "clang/StaticAnalyzer/Core/PathSensitive/CheckerHelpers.h" using namespace clang; using namespace ento; namespace { -class MmapWriteExecChecker : public Checker<check::PreCall> { +class MmapWriteExecChecker + : public Checker<check::BeginFunction, check::PreCall> { CallDescription MmapFn{CDM::CLibrary, {"mmap"}, 6}; CallDescription MprotectFn{CDM::CLibrary, {"mprotect"}, 3}; - static int ProtWrite; - static int ProtExec; - static int ProtRead; const BugType BT{this, "W^X check fails, Write Exec prot flags set", "Security"}; + mutable bool FlagsInitialized = false; + mutable int ProtRead = 0x01; + mutable int ProtWrite = 0x02; + mutable int ProtExec = 0x04; + public: + void checkBeginFunction(CheckerContext &C) const; void checkPreCall(const CallEvent &Call, CheckerContext &C) const; + int ProtExecOv; int ProtReadOv; }; } -int MmapWriteExecChecker::ProtWrite = 0x02; -int MmapWriteExecChecker::ProtExec = 0x04; -int MmapWriteExecChecker::ProtRead = 0x01; +void MmapWriteExecChecker::checkBeginFunction(CheckerContext &C) const { + if (FlagsInitialized) + return; + + FlagsInitialized = true; + + const std::optional<int> FoundProtRead = + tryExpandAsInteger("PROT_READ", C.getPreprocessor()); + const std::optional<int> FoundProtWrite = + tryExpandAsInteger("PROT_WRITE", C.getPreprocessor()); + const std::optional<int> FoundProtExec = + tryExpandAsInteger("PROT_EXEC", C.getPreprocessor()); + if (FoundProtRead && FoundProtWrite && FoundProtExec) { + ProtRead = *FoundProtRead; + ProtWrite = *FoundProtWrite; + ProtExec = *FoundProtExec; + } else { + // FIXME: Are these useful? + ProtRead = ProtReadOv; + ProtExec = ProtExecOv; + } +} void MmapWriteExecChecker::checkPreCall(const CallEvent &Call, CheckerContext &C) const { @@ -54,16 +79,8 @@ void MmapWriteExecChecker::checkPreCall(const CallEvent &Call, if (!ProtLoc) return; int64_t Prot = ProtLoc->getValue().getSExtValue(); - if (ProtExecOv != ProtExec) - ProtExec = ProtExecOv; - if (ProtReadOv != ProtRead) - ProtRead = ProtReadOv; - - // Wrong settings - if (ProtRead == ProtExec) - return; - if ((Prot & (ProtWrite | ProtExec)) == (ProtWrite | ProtExec)) { + if ((Prot & ProtWrite) && (Prot & ProtExec)) { ExplodedNode *N = C.generateNonFatalErrorNode(); if (!N) return; diff --git a/clang/test/Analysis/mmap-writeexec.c b/clang/test/Analysis/mmap-writeexec.c index 8fd86ceb9d2a2..88fcc7788e683 100644 --- a/clang/test/Analysis/mmap-writeexec.c +++ b/clang/test/Analysis/mmap-writeexec.c @@ -1,13 +1,14 @@ // RUN: %clang_analyze_cc1 -triple i686-unknown-linux -analyzer-checker=alpha.security.MmapWriteExec -analyzer-config alpha.security.MmapWriteExec:MmapProtExec=1 -analyzer-config alpha.security.MmapWriteExec:MmapProtRead=4 -DUSE_ALTERNATIVE_PROT_EXEC_DEFINITION -verify %s // RUN: %clang_analyze_cc1 -triple x86_64-unknown-apple-darwin10 -analyzer-checker=alpha.security.MmapWriteExec -verify %s -#define PROT_WRITE 0x02 #ifndef USE_ALTERNATIVE_PROT_EXEC_DEFINITION -#define PROT_EXEC 0x04 -#define PROT_READ 0x01 -#else #define PROT_EXEC 0x01 +#define PROT_WRITE 0x02 #define PROT_READ 0x04 +#else +#define PROT_EXEC 0x08 +#define PROT_WRITE 0x04 +#define PROT_READ 0x02 #endif #define MAP_PRIVATE 0x0002 #define MAP_ANON 0x1000 `````````` </details> https://github.com/llvm/llvm-project/pull/97078 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
