[sanitizer] Initial implementation of a Hardened Allocator

Summary:
This is an initial implementation of a Hardened Allocator based on Sanitizer Common's CombinedAllocator.
It aims at mitigating heap based vulnerabilities by adding several features to the base allocator, while staying relatively fast.
The following were implemented:
- additional consistency checks on the allocation function parameters and on the heap chunks;
- use of checksum protected chunk header, to detect corruption;
- randomness to the allocator base;
- delayed freelist (quarantine), to mitigate use after free and overall determinism.
Additional mitigations are in the works.

Reviewers: eugenis, aizatsky, pcc, krasin, vitalybuka, glider, dvyukov, kcc

Subscribers: kubabrecka, filcab, llvm-commits

Differential Revision: http://reviews.llvm.org/D20084

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@271968 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 63 insertions, 0 deletions

diff --git a/lib/scudo/scudo_allocator.h b/lib/scudo/scudo_allocator.h
new file mode 100644
index 000000000..7e9c78860
--- /dev/null
+++ b/lib/scudo/scudo_allocator.h
@@ -0,0 +1,63 @@
+//===-- scudo_allocator.h ---------------------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+///
+/// Header for scudo_allocator.cpp.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef SCUDO_ALLOCATOR_H_
+#define SCUDO_ALLOCATOR_H_
+
+#ifndef __x86_64__
+# error "The Scudo hardened allocator currently only supports x86_64."
+#endif
+
+#include "scudo_flags.h"
+
+#include "sanitizer_common/sanitizer_allocator.h"
+
+namespace __scudo {
+
+enum AllocType : u8 {
+  FromMalloc    = 0, // Memory block came from malloc, realloc, calloc, etc.
+  FromNew       = 1, // Memory block came from operator new.
+  FromNewArray  = 2, // Memory block came from operator new [].
+  FromMemalign  = 3, // Memory block came from memalign, posix_memalign, etc.
+};
+
+struct AllocatorOptions {
+  u32 QuarantineSizeMb;
+  u32 ThreadLocalQuarantineSizeKb;
+  bool MayReturnNull;
+  bool DeallocationTypeMismatch;
+  bool DeleteSizeMismatch;
+  bool ZeroContents;
+
+  void setFrom(const Flags *f, const CommonFlags *cf);
+  void copyTo(Flags *f, CommonFlags *cf) const;
+};
+
+void initAllocator(const AllocatorOptions &options);
+void drainQuarantine();
+
+void *scudoMalloc(uptr Size, AllocType Type);
+void scudoFree(void *Ptr, AllocType Type);
+void scudoSizedFree(void *Ptr, uptr Size, AllocType Type);
+void *scudoRealloc(void *Ptr, uptr Size);
+void *scudoCalloc(uptr NMemB, uptr Size);
+void *scudoMemalign(uptr Alignment, uptr Size);
+void *scudoValloc(uptr Size);
+void *scudoPvalloc(uptr Size);
+int scudoPosixMemalign(void **MemPtr, uptr Alignment, uptr Size);
+void *scudoAlignedAlloc(uptr Alignment, uptr Size);
+uptr scudoMallocUsableSize(void *Ptr);
+
+} // namespace __scudo
+
+#endif  // SCUDO_ALLOCATOR_H_