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Abstract interactions with valgrind behind new checkmem.h
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-152
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11 files changed

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-152
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‎Makefile.am‎

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@@ -47,6 +47,7 @@ noinst_HEADERS += src/modinv64_impl.h
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noinst_HEADERS += src/precomputed_ecmult.h
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noinst_HEADERS += src/precomputed_ecmult_gen.h
4949
noinst_HEADERS += src/assumptions.h
50+
noinst_HEADERS += src/checkmem.h
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noinst_HEADERS += src/util.h
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noinst_HEADERS += src/int128.h
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noinst_HEADERS += src/int128_impl.h

‎src/checkmem.h‎

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@@ -0,0 +1,74 @@
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/***********************************************************************
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* Copyright (c) 2022 Pieter Wuille *
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* Distributed under the MIT software license, see the accompanying *
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* file COPYING or https://www.opensource.org/licenses/mit-license.php.*
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***********************************************************************/
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/* The code here is inspired by Kris Kwiatkowski's approach in
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* https://github.com/kriskwiatkowski/pqc/blob/main/src/common/ct_check.h
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* to provide a general interface for memory-checking mechanisms, primarily
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* for constant-time checking.
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*/
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/* These macros are defined by this header file:
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*
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* - SECP256K1_CHECKMEM_ENABLED:
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* - 1 if memory-checking integration is available, 0 otherwise.
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* This is just a compile-time macro. Use the next macro to check it is actually
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* available at runtime.
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* - SECP256K1_CHECKMEM_RUNNING():
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* - Acts like a function call, returning 1 if memory checking is available
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* at runtime.
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* - SECP256K1_CHECKMEM_CHECK(p, len):
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* - Assert or otherwise fail in case the len-byte memory block pointed to by p is
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* not considered entirely defined.
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* - SECP256K1_CHECKMEM_CHECK_VERIFY(p, len):
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* - Like SECP256K1_CHECKMEM_CHECK, but only works in VERIFY mode.
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* - SECP256K1_CHECKMEM_UNDEFINE(p, len):
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* - marks the len-byte memory block pointed to by p as undefined data (secret data,
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* in the context of constant-time checking).
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* - SECP256K1_CHECKMEM_DEFINE(p, len):
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* - marks the len-byte memory pointed to by p as defined data (public data, in the
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* context of constant-time checking).
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*
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*/
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#ifndef SECP256K1_CHECKMEM_H
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#define SECP256K1_CHECKMEM_H
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/* Define a statement-like macro that ignores the arguments. */
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#define SECP256K1_CHECKMEM_NOOP(p, len) do { (void)(p); (void)(len); } while(0)
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/* If valgrind integration is desired (through the VALGRIND define), implement the
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* SECP256K1_CHECKMEM_* macros using valgrind. */
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#if !defined SECP256K1_CHECKMEM_ENABLED
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# if defined VALGRIND
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# include <stddef.h>
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# include <valgrind/memcheck.h>
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# define SECP256K1_CHECKMEM_ENABLED 1
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# define SECP256K1_CHECKMEM_UNDEFINE(p, len) VALGRIND_MAKE_MEM_UNDEFINED((p), (len))
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# define SECP256K1_CHECKMEM_DEFINE(p, len) VALGRIND_MAKE_MEM_DEFINED((p), (len))
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# define SECP256K1_CHECKMEM_CHECK(p, len) VALGRIND_CHECK_MEM_IS_DEFINED((p), (len))
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/* VALGRIND_MAKE_MEM_DEFINED returns 0 iff not running on memcheck.
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* This is more precise than the RUNNING_ON_VALGRIND macro, which
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* checks for valgrind in general instead of memcheck specifically. */
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# define SECP256K1_CHECKMEM_RUNNING() (VALGRIND_MAKE_MEM_DEFINED(NULL, 0) != 0)
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# endif
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#endif
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/* As a fall-back, map these macros to dummy statements. */
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#if !defined SECP256K1_CHECKMEM_ENABLED
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# define SECP256K1_CHECKMEM_ENABLED 0
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# define SECP256K1_CHECKMEM_UNDEFINE(p, len) SECP256K1_CHECKMEM_NOOP((p), (len))
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# define SECP256K1_CHECKMEM_DEFINE(p, len) SECP256K1_CHECKMEM_NOOP((p), (len))
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# define SECP256K1_CHECKMEM_CHECK(p, len) SECP256K1_CHECKMEM_NOOP((p), (len))
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# define SECP256K1_CHECKMEM_RUNNING() (0)
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#endif
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#if defined VERIFY
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#define SECP256K1_CHECKMEM_CHECK_VERIFY(p, len) SECP256K1_CHECKMEM_CHECK((p), (len))
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#else
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#define SECP256K1_CHECKMEM_CHECK_VERIFY(p, len) SECP256K1_CHECKMEM_NOOP((p), (len))
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#endif
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#endif /* SECP256K1_CHECKMEM_H */

‎src/field_10x26_impl.h‎

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Original file line numberDiff line numberDiff line change
@@ -7,6 +7,7 @@
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#ifndef SECP256K1_FIELD_REPR_IMPL_H
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#define SECP256K1_FIELD_REPR_IMPL_H
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#include "checkmem.h"
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#include "util.h"
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#include "field.h"
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#include "modinv32_impl.h"
@@ -1132,7 +1133,7 @@ static void secp256k1_fe_sqr(secp256k1_fe *r, const secp256k1_fe *a) {
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11331134
static SECP256K1_INLINE void secp256k1_fe_cmov(secp256k1_fe *r, const secp256k1_fe *a, int flag) {
11341135
uint32_t mask0, mask1;
1135-
VG_CHECK_VERIFY(r->n, sizeof(r->n));
1136+
SECP256K1_CHECKMEM_CHECK_VERIFY(r->n, sizeof(r->n));
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mask0 = flag + ~((uint32_t)0);
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mask1 = ~mask0;
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r->n[0] = (r->n[0] & mask0) | (a->n[0] & mask1);
@@ -1231,7 +1232,7 @@ static SECP256K1_INLINE void secp256k1_fe_half(secp256k1_fe *r) {
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static SECP256K1_INLINE void secp256k1_fe_storage_cmov(secp256k1_fe_storage *r, const secp256k1_fe_storage *a, int flag) {
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uint32_t mask0, mask1;
1234-
VG_CHECK_VERIFY(r->n, sizeof(r->n));
1235+
SECP256K1_CHECKMEM_CHECK_VERIFY(r->n, sizeof(r->n));
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mask0 = flag + ~((uint32_t)0);
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mask1 = ~mask0;
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r->n[0] = (r->n[0] & mask0) | (a->n[0] & mask1);

‎src/field_5x52_impl.h‎

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Original file line numberDiff line numberDiff line change
@@ -7,6 +7,7 @@
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#ifndef SECP256K1_FIELD_REPR_IMPL_H
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#define SECP256K1_FIELD_REPR_IMPL_H
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#include "checkmem.h"
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#include "util.h"
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#include "field.h"
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#include "modinv64_impl.h"
@@ -472,7 +473,7 @@ static void secp256k1_fe_sqr(secp256k1_fe *r, const secp256k1_fe *a) {
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473474
static SECP256K1_INLINE void secp256k1_fe_cmov(secp256k1_fe *r, const secp256k1_fe *a, int flag) {
474475
uint64_t mask0, mask1;
475-
VG_CHECK_VERIFY(r->n, sizeof(r->n));
476+
SECP256K1_CHECKMEM_CHECK_VERIFY(r->n, sizeof(r->n));
476477
mask0 = flag + ~((uint64_t)0);
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mask1 = ~mask0;
478479
r->n[0] = (r->n[0] & mask0) | (a->n[0] & mask1);
@@ -555,7 +556,7 @@ static SECP256K1_INLINE void secp256k1_fe_half(secp256k1_fe *r) {
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556557
static SECP256K1_INLINE void secp256k1_fe_storage_cmov(secp256k1_fe_storage *r, const secp256k1_fe_storage *a, int flag) {
557558
uint64_t mask0, mask1;
558-
VG_CHECK_VERIFY(r->n, sizeof(r->n));
559+
SECP256K1_CHECKMEM_CHECK_VERIFY(r->n, sizeof(r->n));
559560
mask0 = flag + ~((uint64_t)0);
560561
mask1 = ~mask0;
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r->n[0] = (r->n[0] & mask0) | (a->n[0] & mask1);

‎src/scalar_4x64_impl.h‎

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@@ -7,6 +7,7 @@
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#ifndef SECP256K1_SCALAR_REPR_IMPL_H
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#define SECP256K1_SCALAR_REPR_IMPL_H
99

10+
#include "checkmem.h"
1011
#include "int128.h"
1112
#include "modinv64_impl.h"
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@@ -810,7 +811,7 @@ SECP256K1_INLINE static void secp256k1_scalar_mul_shift_var(secp256k1_scalar *r,
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811812
static SECP256K1_INLINE void secp256k1_scalar_cmov(secp256k1_scalar *r, const secp256k1_scalar *a, int flag) {
812813
uint64_t mask0, mask1;
813-
VG_CHECK_VERIFY(r->d, sizeof(r->d));
814+
SECP256K1_CHECKMEM_CHECK_VERIFY(r->d, sizeof(r->d));
814815
mask0 = flag + ~((uint64_t)0);
815816
mask1 = ~mask0;
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r->d[0] = (r->d[0] & mask0) | (a->d[0] & mask1);

‎src/scalar_8x32_impl.h‎

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@@ -7,6 +7,7 @@
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#ifndef SECP256K1_SCALAR_REPR_IMPL_H
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#define SECP256K1_SCALAR_REPR_IMPL_H
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10+
#include "checkmem.h"
1011
#include "modinv32_impl.h"
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1213
/* Limbs of the secp256k1 order. */
@@ -631,7 +632,7 @@ SECP256K1_INLINE static void secp256k1_scalar_mul_shift_var(secp256k1_scalar *r,
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632633
static SECP256K1_INLINE void secp256k1_scalar_cmov(secp256k1_scalar *r, const secp256k1_scalar *a, int flag) {
633634
uint32_t mask0, mask1;
634-
VG_CHECK_VERIFY(r->d, sizeof(r->d));
635+
SECP256K1_CHECKMEM_CHECK_VERIFY(r->d, sizeof(r->d));
635636
mask0 = flag + ~((uint32_t)0);
636637
mask1 = ~mask0;
637638
r->d[0] = (r->d[0] & mask0) | (a->d[0] & mask1);

‎src/scalar_low_impl.h‎

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@@ -7,6 +7,7 @@
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#ifndef SECP256K1_SCALAR_REPR_IMPL_H
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#define SECP256K1_SCALAR_REPR_IMPL_H
99

10+
#include "checkmem.h"
1011
#include "scalar.h"
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1213
#include <string.h>
@@ -115,7 +116,7 @@ SECP256K1_INLINE static int secp256k1_scalar_eq(const secp256k1_scalar *a, const
115116

116117
static SECP256K1_INLINE void secp256k1_scalar_cmov(secp256k1_scalar *r, const secp256k1_scalar *a, int flag) {
117118
uint32_t mask0, mask1;
118-
VG_CHECK_VERIFY(r, sizeof(*r));
119+
SECP256K1_CHECKMEM_CHECK_VERIFY(r, sizeof(*r));
119120
mask0 = flag + ~((uint32_t)0);
120121
mask1 = ~mask0;
121122
*r = (*r & mask0) | (*a & mask1);

‎src/secp256k1.c‎

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@@ -21,6 +21,7 @@
2121
#include "../include/secp256k1_preallocated.h"
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2323
#include "assumptions.h"
24+
#include "checkmem.h"
2425
#include "util.h"
2526

2627
#include "field_impl.h"
@@ -40,10 +41,6 @@
4041
# error "secp256k1.h processed without SECP256K1_BUILD defined while building secp256k1.c"
4142
#endif
4243

43-
#if defined(VALGRIND)
44-
# include <valgrind/memcheck.h>
45-
#endif
46-
4744
#define ARG_CHECK(cond) do { \
4845
if (EXPECT(!(cond), 0)) { \
4946
secp256k1_callback_call(&ctx->illegal_callback, #cond); \
@@ -215,17 +212,10 @@ void secp256k1_scratch_space_destroy(const secp256k1_context *ctx, secp256k1_scr
215212
}
216213

217214
/* Mark memory as no-longer-secret for the purpose of analysing constant-time behaviour
218-
* of the software. This is setup for use with valgrind but could be substituted with
219-
* the appropriate instrumentation for other analysis tools.
215+
* of the software.
220216
*/
221217
static SECP256K1_INLINE void secp256k1_declassify(const secp256k1_context* ctx, const void *p, size_t len) {
222-
#if defined(VALGRIND)
223-
if (EXPECT(ctx->declassify,0)) VALGRIND_MAKE_MEM_DEFINED(p, len);
224-
#else
225-
(void)ctx;
226-
(void)p;
227-
(void)len;
228-
#endif
218+
if (EXPECT(ctx->declassify, 0)) SECP256K1_CHECKMEM_DEFINE(p, len);
229219
}
230220

231221
static int secp256k1_pubkey_load(const secp256k1_context* ctx, secp256k1_ge* ge, const secp256k1_pubkey* pubkey) {

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