secp256k1

src/checkmem.h

/***********************************************************************
* Copyright (c) 2022 Pieter Wuille *
* Distributed under the MIT software license, see the accompanying *
* file COPYING or https://www.opensource.org/licenses/mit-license.php.*
***********************************************************************/
/* The code here is inspired by Kris Kwiatkowski's approach in
* https://github.com/kriskwiatkowski/pqc/blob/main/src/common/ct_check.h
* to provide a general interface for memory-checking mechanisms, primarily
* for constant-time checking.
*/
/* These macros are defined by this header file:
*
* - SECP256K1_CHECKMEM_ENABLED:
* - 1 if memory-checking integration is available, 0 otherwise.
* This is just a compile-time macro. Use the next macro to check it is actually
* available at runtime.
* - SECP256K1_CHECKMEM_RUNNING():
* - Acts like a function call, returning 1 if memory checking is available
* at runtime.
* - SECP256K1_CHECKMEM_CHECK(p, len):
* - Assert or otherwise fail in case the len-byte memory block pointed to by p is
* not considered entirely defined.
* - SECP256K1_CHECKMEM_CHECK_VERIFY(p, len):
* - Like SECP256K1_CHECKMEM_CHECK, but only works in VERIFY mode.
* - SECP256K1_CHECKMEM_UNDEFINE(p, len):
* - marks the len-byte memory block pointed to by p as undefined data (secret data,
* in the context of constant-time checking).
* - SECP256K1_CHECKMEM_DEFINE(p, len):
* - marks the len-byte memory pointed to by p as defined data (public data, in the
* context of constant-time checking).
* - SECP256K1_CHECKMEM_MSAN_DEFINE(p, len):
* - Like SECP256K1_CHECKMEM_DEFINE, but applies only to memory_sanitizer.
*
*/
#ifndef SECP256K1_CHECKMEM_H
#define SECP256K1_CHECKMEM_H
/* Define a statement-like macro that ignores the arguments. */
#define SECP256K1_CHECKMEM_NOOP(p, len) do { (void)(p); (void)(len); } while(0)
expanded from macro 'SECP256K1_CHECKMEM_NOOP'
/* If compiling under msan, map the SECP256K1_CHECKMEM_* functionality to msan.
* Choose this preferentially, even when VALGRIND is defined, as msan-compiled
* binaries can't be run under valgrind anyway. */
#if defined(__has_feature)
# if __has_feature(memory_sanitizer)
# include <sanitizer/msan_interface.h>
# define SECP256K1_CHECKMEM_ENABLED 1
# if defined(__clang__) && ((__clang_major__ == 21 && __clang_minor__ >= 1) || __clang_major__ >= 22)
# define SECP256K1_CHECKMEM_UNDEFINE(p, len) do { \
/* Work around https://github.com/llvm/llvm-project/issues/160094 */ \
_Pragma("clang diagnostic push") \
_Pragma("clang diagnostic ignored \"-Wuninitialized-const-pointer\"") \
__msan_allocated_memory((p), (len)); \
_Pragma("clang diagnostic pop") \
} while(0)
# else
# define SECP256K1_CHECKMEM_UNDEFINE(p, len) __msan_allocated_memory((p), (len))
# endif
# define SECP256K1_CHECKMEM_DEFINE(p, len) __msan_unpoison((p), (len))
# define SECP256K1_CHECKMEM_MSAN_DEFINE(p, len) __msan_unpoison((p), (len))
# define SECP256K1_CHECKMEM_CHECK(p, len) __msan_check_mem_is_initialized((p), (len))
# define SECP256K1_CHECKMEM_RUNNING() (1)
# endif
#endif
#if !defined SECP256K1_CHECKMEM_MSAN_DEFINE
# define SECP256K1_CHECKMEM_MSAN_DEFINE(p, len) SECP256K1_CHECKMEM_NOOP((p), (len))
expanded from macro 'SECP256K1_CHECKMEM_MSAN_DEFINE'
#endif
/* If valgrind integration is desired (through the VALGRIND define), implement the
* SECP256K1_CHECKMEM_* macros using valgrind. */
#if !defined SECP256K1_CHECKMEM_ENABLED
# if defined VALGRIND
# include <stddef.h>
# if defined(__clang__) && defined(__APPLE__)
# pragma clang diagnostic push
# pragma clang diagnostic ignored "-Wreserved-identifier"
# endif
# include <valgrind/memcheck.h>
# if defined(__clang__) && defined(__APPLE__)
# pragma clang diagnostic pop
# endif
# define SECP256K1_CHECKMEM_ENABLED 1
# define SECP256K1_CHECKMEM_UNDEFINE(p, len) VALGRIND_MAKE_MEM_UNDEFINED((p), (len))
# define SECP256K1_CHECKMEM_DEFINE(p, len) VALGRIND_MAKE_MEM_DEFINED((p), (len))
# define SECP256K1_CHECKMEM_CHECK(p, len) VALGRIND_CHECK_MEM_IS_DEFINED((p), (len))
/* VALGRIND_MAKE_MEM_DEFINED returns 0 iff not running on memcheck.
* This is more precise than the RUNNING_ON_VALGRIND macro, which
* checks for valgrind in general instead of memcheck specifically. */
# define SECP256K1_CHECKMEM_RUNNING() (VALGRIND_MAKE_MEM_DEFINED(NULL, 0) != 0)
# endif
#endif
/* As a fall-back, map these macros to dummy statements. */
#if !defined SECP256K1_CHECKMEM_ENABLED
# define SECP256K1_CHECKMEM_ENABLED 0
# define SECP256K1_CHECKMEM_UNDEFINE(p, len) SECP256K1_CHECKMEM_NOOP((p), (len))
# define SECP256K1_CHECKMEM_DEFINE(p, len) SECP256K1_CHECKMEM_NOOP((p), (len))
# define SECP256K1_CHECKMEM_CHECK(p, len) SECP256K1_CHECKMEM_NOOP((p), (len))
# define SECP256K1_CHECKMEM_RUNNING() (0)
#endif
#if defined VERIFY
#define SECP256K1_CHECKMEM_CHECK_VERIFY(p, len) SECP256K1_CHECKMEM_CHECK((p), (len))
#else
#define SECP256K1_CHECKMEM_CHECK_VERIFY(p, len) SECP256K1_CHECKMEM_NOOP((p), (len))
#endif
#endif /* SECP256K1_CHECKMEM_H */