1eda8bd0fc07df35c9ad7de5b698bb717b063e7afRichard Smith//===-- ubsan_type_hash.h ---------------------------------------*- C++ -*-===// 2eda8bd0fc07df35c9ad7de5b698bb717b063e7afRichard Smith// 3eda8bd0fc07df35c9ad7de5b698bb717b063e7afRichard Smith// The LLVM Compiler Infrastructure 4eda8bd0fc07df35c9ad7de5b698bb717b063e7afRichard Smith// 5eda8bd0fc07df35c9ad7de5b698bb717b063e7afRichard Smith// This file is distributed under the University of Illinois Open Source 6eda8bd0fc07df35c9ad7de5b698bb717b063e7afRichard Smith// License. See LICENSE.TXT for details. 7eda8bd0fc07df35c9ad7de5b698bb717b063e7afRichard Smith// 8eda8bd0fc07df35c9ad7de5b698bb717b063e7afRichard Smith//===----------------------------------------------------------------------===// 9eda8bd0fc07df35c9ad7de5b698bb717b063e7afRichard Smith// 10eda8bd0fc07df35c9ad7de5b698bb717b063e7afRichard Smith// Hashing of types for Clang's undefined behavior checker. 11eda8bd0fc07df35c9ad7de5b698bb717b063e7afRichard Smith// 12eda8bd0fc07df35c9ad7de5b698bb717b063e7afRichard Smith//===----------------------------------------------------------------------===// 13eda8bd0fc07df35c9ad7de5b698bb717b063e7afRichard Smith#ifndef UBSAN_TYPE_HASH_H 14eda8bd0fc07df35c9ad7de5b698bb717b063e7afRichard Smith#define UBSAN_TYPE_HASH_H 15eda8bd0fc07df35c9ad7de5b698bb717b063e7afRichard Smith 16eda8bd0fc07df35c9ad7de5b698bb717b063e7afRichard Smith#include "sanitizer_common/sanitizer_common.h" 17eda8bd0fc07df35c9ad7de5b698bb717b063e7afRichard Smith 18eda8bd0fc07df35c9ad7de5b698bb717b063e7afRichard Smithnamespace __ubsan { 19eda8bd0fc07df35c9ad7de5b698bb717b063e7afRichard Smith 20eda8bd0fc07df35c9ad7de5b698bb717b063e7afRichard Smithtypedef uptr HashValue; 21eda8bd0fc07df35c9ad7de5b698bb717b063e7afRichard Smith 2225ee97fe8ada76755c8bd1087fac9cc3cd03b28cRichard Smith/// \brief Information about the dynamic type of an object (extracted from its 2325ee97fe8ada76755c8bd1087fac9cc3cd03b28cRichard Smith/// vptr). 2425ee97fe8ada76755c8bd1087fac9cc3cd03b28cRichard Smithclass DynamicTypeInfo { 2525ee97fe8ada76755c8bd1087fac9cc3cd03b28cRichard Smith const char *MostDerivedTypeName; 2625ee97fe8ada76755c8bd1087fac9cc3cd03b28cRichard Smith sptr Offset; 270ad23f7f860e27b8b9a889be665cfaea830503ceRichard Smith const char *SubobjectTypeName; 2825ee97fe8ada76755c8bd1087fac9cc3cd03b28cRichard Smith 2925ee97fe8ada76755c8bd1087fac9cc3cd03b28cRichard Smithpublic: 300ad23f7f860e27b8b9a889be665cfaea830503ceRichard Smith DynamicTypeInfo(const char *MDTN, sptr Offset, const char *STN) 310ad23f7f860e27b8b9a889be665cfaea830503ceRichard Smith : MostDerivedTypeName(MDTN), Offset(Offset), SubobjectTypeName(STN) {} 3225ee97fe8ada76755c8bd1087fac9cc3cd03b28cRichard Smith 3325ee97fe8ada76755c8bd1087fac9cc3cd03b28cRichard Smith /// Determine whether the object had a valid dynamic type. 3425ee97fe8ada76755c8bd1087fac9cc3cd03b28cRichard Smith bool isValid() const { return MostDerivedTypeName; } 3525ee97fe8ada76755c8bd1087fac9cc3cd03b28cRichard Smith /// Get the name of the most-derived type of the object. 3625ee97fe8ada76755c8bd1087fac9cc3cd03b28cRichard Smith const char *getMostDerivedTypeName() const { return MostDerivedTypeName; } 3725ee97fe8ada76755c8bd1087fac9cc3cd03b28cRichard Smith /// Get the offset from the most-derived type to this base class. 3825ee97fe8ada76755c8bd1087fac9cc3cd03b28cRichard Smith sptr getOffset() const { return Offset; } 390ad23f7f860e27b8b9a889be665cfaea830503ceRichard Smith /// Get the name of the most-derived type at the specified offset. 400ad23f7f860e27b8b9a889be665cfaea830503ceRichard Smith const char *getSubobjectTypeName() const { return SubobjectTypeName; } 4125ee97fe8ada76755c8bd1087fac9cc3cd03b28cRichard Smith}; 4225ee97fe8ada76755c8bd1087fac9cc3cd03b28cRichard Smith 4325ee97fe8ada76755c8bd1087fac9cc3cd03b28cRichard Smith/// \brief Get information about the dynamic type of an object. 44799172d60d32feb1acba1a6867f3a9c39a999e5cPirama Arumuga NainarDynamicTypeInfo getDynamicTypeInfoFromObject(void *Object); 45799172d60d32feb1acba1a6867f3a9c39a999e5cPirama Arumuga Nainar 46799172d60d32feb1acba1a6867f3a9c39a999e5cPirama Arumuga Nainar/// \brief Get information about the dynamic type of an object from its vtable. 47799172d60d32feb1acba1a6867f3a9c39a999e5cPirama Arumuga NainarDynamicTypeInfo getDynamicTypeInfoFromVtable(void *Vtable); 4825ee97fe8ada76755c8bd1087fac9cc3cd03b28cRichard Smith 49eda8bd0fc07df35c9ad7de5b698bb717b063e7afRichard Smith/// \brief Check whether the dynamic type of \p Object has a \p Type subobject 50eda8bd0fc07df35c9ad7de5b698bb717b063e7afRichard Smith/// at offset 0. 51eda8bd0fc07df35c9ad7de5b698bb717b063e7afRichard Smith/// \return \c true if the type matches, \c false if not. 5226a725f0b2fd30b98adae6353b432d0c955e10bdRichard Smithbool checkDynamicType(void *Object, void *Type, HashValue Hash); 5326a725f0b2fd30b98adae6353b432d0c955e10bdRichard Smith 5426a725f0b2fd30b98adae6353b432d0c955e10bdRichard Smithconst unsigned VptrTypeCacheSize = 128; 5526a725f0b2fd30b98adae6353b432d0c955e10bdRichard Smith 56c58a43648cd6121c51a2e795a28e2ef90d7813e6Pirama Arumuga Nainar/// A sanity check for Vtable. Offsets to top must be reasonably small 57c58a43648cd6121c51a2e795a28e2ef90d7813e6Pirama Arumuga Nainar/// numbers (by absolute value). It's a weak check for Vtable corruption. 58c58a43648cd6121c51a2e795a28e2ef90d7813e6Pirama Arumuga Nainarconst int VptrMaxOffsetToTop = 1<<20; 59c58a43648cd6121c51a2e795a28e2ef90d7813e6Pirama Arumuga Nainar 6026a725f0b2fd30b98adae6353b432d0c955e10bdRichard Smith/// \brief A cache of the results of checkDynamicType. \c checkDynamicType would 6126a725f0b2fd30b98adae6353b432d0c955e10bdRichard Smith/// return \c true (modulo hash collisions) if 6226a725f0b2fd30b98adae6353b432d0c955e10bdRichard Smith/// \code 6326a725f0b2fd30b98adae6353b432d0c955e10bdRichard Smith/// __ubsan_vptr_type_cache[Hash % VptrTypeCacheSize] == Hash 6426a725f0b2fd30b98adae6353b432d0c955e10bdRichard Smith/// \endcode 6518af39e73d651f1903f2d46ac51b3842b378763fWill Dietzextern "C" SANITIZER_INTERFACE_ATTRIBUTE 6618af39e73d651f1903f2d46ac51b3842b378763fWill DietzHashValue __ubsan_vptr_type_cache[VptrTypeCacheSize]; 67eda8bd0fc07df35c9ad7de5b698bb717b063e7afRichard Smith 68eda8bd0fc07df35c9ad7de5b698bb717b063e7afRichard Smith} // namespace __ubsan 69eda8bd0fc07df35c9ad7de5b698bb717b063e7afRichard Smith 70eda8bd0fc07df35c9ad7de5b698bb717b063e7afRichard Smith#endif // UBSAN_TYPE_HASH_H 71