From 26dde295d0ad12a011fc4062ad642852f7ff68fa Mon Sep 17 00:00:00 2001 From: Jonas Nick Date: Sat, 6 Jan 2024 15:37:30 +0000 Subject: [PATCH] extrakeys: add secp256k1_pubkey_sort --- include/secp256k1_extrakeys.h | 15 ++ src/modules/extrakeys/Makefile.am.include | 2 + src/modules/extrakeys/hsort.h | 22 +++ src/modules/extrakeys/hsort_impl.h | 116 +++++++++++++ src/modules/extrakeys/main_impl.h | 35 ++++ src/modules/extrakeys/tests_impl.h | 194 ++++++++++++++++++++++ 6 files changed, 384 insertions(+) create mode 100644 src/modules/extrakeys/hsort.h create mode 100644 src/modules/extrakeys/hsort_impl.h diff --git a/include/secp256k1_extrakeys.h b/include/secp256k1_extrakeys.h index ad70b92f95..9f0911634a 100644 --- a/include/secp256k1_extrakeys.h +++ b/include/secp256k1_extrakeys.h @@ -240,6 +240,21 @@ SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_keypair_xonly_tweak_add const unsigned char *tweak32 ) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3); +/** Sort public keys using lexicographic order of their compressed + * serialization. + * + * Returns: 0 if the arguments are invalid. 1 otherwise. + * + * Args: ctx: pointer to a context object + * In: pubkeys: array of pointers to pubkeys to sort + * n_pubkeys: number of elements in the pubkeys array + */ +SECP256K1_API int secp256k1_pubkey_sort( + const secp256k1_context *ctx, + const secp256k1_pubkey **pubkeys, + size_t n_pubkeys +) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2); + #ifdef __cplusplus } #endif diff --git a/src/modules/extrakeys/Makefile.am.include b/src/modules/extrakeys/Makefile.am.include index 0d901ec1f4..d0ff7c4257 100644 --- a/src/modules/extrakeys/Makefile.am.include +++ b/src/modules/extrakeys/Makefile.am.include @@ -2,3 +2,5 @@ include_HEADERS += include/secp256k1_extrakeys.h noinst_HEADERS += src/modules/extrakeys/tests_impl.h noinst_HEADERS += src/modules/extrakeys/tests_exhaustive_impl.h noinst_HEADERS += src/modules/extrakeys/main_impl.h +noinst_HEADERS += src/modules/extrakeys/hsort.h +noinst_HEADERS += src/modules/extrakeys/hsort_impl.h \ No newline at end of file diff --git a/src/modules/extrakeys/hsort.h b/src/modules/extrakeys/hsort.h new file mode 100644 index 0000000000..5352ef1e39 --- /dev/null +++ b/src/modules/extrakeys/hsort.h @@ -0,0 +1,22 @@ +/*********************************************************************** + * Copyright (c) 2021 Russell O'Connor, Jonas Nick * + * Distributed under the MIT software license, see the accompanying * + * file COPYING or https://www.opensource.org/licenses/mit-license.php.* + ***********************************************************************/ + +#ifndef SECP256K1_HSORT_H +#define SECP256K1_HSORT_H + +#include +#include + +/* In-place, iterative heapsort with an interface matching glibc's qsort_r. This + * is preferred over standard library implementations because they generally + * make no guarantee about being fast for malicious inputs. + * + * See the qsort_r manpage for a description of the interface. + */ +static void secp256k1_hsort(void *ptr, size_t count, size_t size, + int (*cmp)(const void *, const void *, void *), + void *cmp_data); +#endif diff --git a/src/modules/extrakeys/hsort_impl.h b/src/modules/extrakeys/hsort_impl.h new file mode 100644 index 0000000000..e05aefdf8f --- /dev/null +++ b/src/modules/extrakeys/hsort_impl.h @@ -0,0 +1,116 @@ +/*********************************************************************** + * Copyright (c) 2021 Russell O'Connor, Jonas Nick * + * Distributed under the MIT software license, see the accompanying * + * file COPYING or https://www.opensource.org/licenses/mit-license.php.* + ***********************************************************************/ + +#ifndef SECP256K1_HSORT_IMPL_H +#define SECP256K1_HSORT_IMPL_H + +#include "hsort.h" + +/* An array is a heap when, for all non-zero indexes i, the element at index i + * compares as less than or equal to the element at index parent(i) = (i-1)/2. + */ + +static SECP256K1_INLINE size_t child1(size_t i) { + VERIFY_CHECK(i <= (SIZE_MAX - 1)/2); + return 2*i + 1; +} + +static SECP256K1_INLINE size_t child2(size_t i) { + VERIFY_CHECK(i <= SIZE_MAX/2 - 1); + return child1(i)+1; +} + +static SECP256K1_INLINE void heap_swap64(unsigned char *a, size_t i, size_t j, size_t stride) { + unsigned char tmp[64]; + VERIFY_CHECK(stride <= 64); + memcpy(tmp, a + i*stride, stride); + memmove(a + i*stride, a + j*stride, stride); + memcpy(a + j*stride, tmp, stride); +} + +static SECP256K1_INLINE void heap_swap(unsigned char *a, size_t i, size_t j, size_t stride) { + while (64 < stride) { + heap_swap64(a + (stride - 64), i, j, 64); + stride -= 64; + } + heap_swap64(a, i, j, stride); +} + +static SECP256K1_INLINE void heap_down(unsigned char *a, size_t i, size_t heap_size, size_t stride, + int (*cmp)(const void *, const void *, void *), void *cmp_data) { + while (i < heap_size/2) { + VERIFY_CHECK(i <= SIZE_MAX/2 - 1); + /* Proof: + * i < heap_size/2 + * i + 1 <= heap_size/2 + * 2*i + 2 <= heap_size <= SIZE_MAX + * 2*i <= SIZE_MAX - 2 + */ + + VERIFY_CHECK(child1(i) < heap_size); + /* Proof: + * i < heap_size/2 + * i + 1 <= heap_size/2 + * 2*i + 2 <= heap_size + * 2*i + 1 < heap_size + * child1(i) < heap_size + */ + + /* Let [x] be notation for the contents at a[x*stride]. + * + * If [child1(i)] > [i] and [child2(i)] > [i], + * swap [i] with the larger child to ensure the new parent is larger + * than both children. When [child1(i)] == [child2(i)], swap [i] with + * [child2(i)]. + * Else if [child1(i)] > [i], swap [i] with [child1(i)]. + * Else if [child2(i)] > [i], swap [i] with [child2(i)]. + */ + if (child2(i) < heap_size + && 0 <= cmp(a + child2(i)*stride, a + child1(i)*stride, cmp_data)) { + if (0 < cmp(a + child2(i)*stride, a + i*stride, cmp_data)) { + heap_swap(a, i, child2(i), stride); + i = child2(i); + } else { + /* At this point we have [child2(i)] >= [child1(i)] and we have + * [child2(i)] <= [i], and thus [child1(i)] <= [i] which means + * that the next comparison can be skipped. */ + return; + } + } else if (0 < cmp(a + child1(i)*stride, a + i*stride, cmp_data)) { + heap_swap(a, i, child1(i), stride); + i = child1(i); + } else { + return; + } + } + /* heap_size/2 <= i + * heap_size/2 < i + 1 + * heap_size < 2*i + 2 + * heap_size <= 2*i + 1 + * heap_size <= child1(i) + * Thus child1(i) and child2(i) are now out of bounds and we are at a leaf. + */ +} + +/* In-place heap sort. */ +static void secp256k1_hsort(void *ptr, size_t count, size_t size, + int (*cmp)(const void *, const void *, void *), + void *cmp_data ) { + size_t i; + + for(i = count/2; 0 < i; --i) { + heap_down(ptr, i-1, count, size, cmp, cmp_data); + } + for(i = count; 1 < i; --i) { + /* Extract the largest value from the heap */ + heap_swap(ptr, 0, i-1, size); + + /* Repair the heap condition */ + heap_down(ptr, 0, i-1, size, cmp, cmp_data); + } +} + +#endif diff --git a/src/modules/extrakeys/main_impl.h b/src/modules/extrakeys/main_impl.h index 0c7e266777..782c529012 100644 --- a/src/modules/extrakeys/main_impl.h +++ b/src/modules/extrakeys/main_impl.h @@ -9,6 +9,7 @@ #include "../../../include/secp256k1.h" #include "../../../include/secp256k1_extrakeys.h" +#include "hsort_impl.h" #include "../../util.h" static SECP256K1_INLINE int secp256k1_xonly_pubkey_load(const secp256k1_context* ctx, secp256k1_ge *ge, const secp256k1_xonly_pubkey *pubkey) { @@ -282,4 +283,38 @@ int secp256k1_keypair_xonly_tweak_add(const secp256k1_context* ctx, secp256k1_ke return ret; } +/* This struct wraps a const context pointer to satisfy the secp256k1_hsort api + * which expects a non-const cmp_data pointer. */ +typedef struct { + const secp256k1_context *ctx; +} secp256k1_pubkey_sort_cmp_data; + +static int secp256k1_pubkey_sort_cmp(const void* pk1, const void* pk2, void *cmp_data) { + return secp256k1_ec_pubkey_cmp(((secp256k1_pubkey_sort_cmp_data*)cmp_data)->ctx, + *(secp256k1_pubkey **)pk1, + *(secp256k1_pubkey **)pk2); +} + +int secp256k1_pubkey_sort(const secp256k1_context* ctx, const secp256k1_pubkey **pubkeys, size_t n_pubkeys) { + secp256k1_pubkey_sort_cmp_data cmp_data; + VERIFY_CHECK(ctx != NULL); + ARG_CHECK(pubkeys != NULL); + + cmp_data.ctx = ctx; + + /* Suppress wrong warning (fixed in MSVC 19.33) */ + #if defined(_MSC_VER) && (_MSC_VER < 1933) + #pragma warning(push) + #pragma warning(disable: 4090) + #endif + + secp256k1_hsort(pubkeys, n_pubkeys, sizeof(*pubkeys), secp256k1_pubkey_sort_cmp, &cmp_data); + + #if defined(_MSC_VER) && (_MSC_VER < 1933) + #pragma warning(pop) + #endif + + return 1; +} + #endif diff --git a/src/modules/extrakeys/tests_impl.h b/src/modules/extrakeys/tests_impl.h index 45521d1742..0983208b95 100644 --- a/src/modules/extrakeys/tests_impl.h +++ b/src/modules/extrakeys/tests_impl.h @@ -467,6 +467,194 @@ static void test_keypair_add(void) { } } +static void test_hsort_is_sorted(int *ints, size_t n) { + size_t i; + for (i = 1; i < n; i++) { + CHECK(ints[i-1] <= ints[i]); + } +} + +static int test_hsort_cmp(const void *i1, const void *i2, void *counter) { + *(size_t*)counter += 1; + return *(int*)i1 - *(int*)i2; +} + +#define NUM 64 +static void test_hsort(void) { + int ints[NUM] = { 0 }; + size_t counter = 0; + int i, j; + + secp256k1_hsort(ints, 0, sizeof(ints[0]), test_hsort_cmp, &counter); + CHECK(counter == 0); + secp256k1_hsort(ints, 1, sizeof(ints[0]), test_hsort_cmp, &counter); + CHECK(counter == 0); + secp256k1_hsort(ints, NUM, sizeof(ints[0]), test_hsort_cmp, &counter); + CHECK(counter > 0); + test_hsort_is_sorted(ints, NUM); + + /* Test hsort with length n array and random elements in + * [-interval/2, interval/2] */ + for (i = 0; i < COUNT; i++) { + int n = secp256k1_testrand_int(NUM); + int interval = secp256k1_testrand_int(63) + 1; + for (j = 0; j < n; j++) { + ints[j] = secp256k1_testrand_int(interval) - interval/2; + } + secp256k1_hsort(ints, n, sizeof(ints[0]), test_hsort_cmp, &counter); + test_hsort_is_sorted(ints, n); + } +} +#undef NUM + +static void test_sort_helper(secp256k1_pubkey *pk, size_t *pk_order, size_t n_pk) { + size_t i; + const secp256k1_pubkey *pk_test[5]; + + for (i = 0; i < n_pk; i++) { + pk_test[i] = &pk[pk_order[i]]; + } + secp256k1_pubkey_sort(CTX, pk_test, n_pk); + for (i = 0; i < n_pk; i++) { + CHECK(secp256k1_memcmp_var(pk_test[i], &pk[i], sizeof(*pk_test[i])) == 0); + } +} + +static void permute(size_t *arr, size_t n) { + size_t i; + for (i = n - 1; i >= 1; i--) { + size_t tmp, j; + j = secp256k1_testrand_int(i + 1); + tmp = arr[i]; + arr[i] = arr[j]; + arr[j] = tmp; + } +} + +static void rand_pk(secp256k1_pubkey *pk) { + unsigned char seckey[32]; + secp256k1_keypair keypair; + secp256k1_testrand256(seckey); + CHECK(secp256k1_keypair_create(CTX, &keypair, seckey) == 1); + CHECK(secp256k1_keypair_pub(CTX, pk, &keypair) == 1); +} + +static void test_sort_api(void) { + secp256k1_pubkey pks[2]; + const secp256k1_pubkey *pks_ptr[2]; + + pks_ptr[0] = &pks[0]; + pks_ptr[1] = &pks[1]; + + rand_pk(&pks[0]); + rand_pk(&pks[1]); + + CHECK(secp256k1_pubkey_sort(CTX, pks_ptr, 2) == 1); + CHECK_ILLEGAL(CTX, secp256k1_pubkey_sort(CTX, NULL, 2)); + CHECK(secp256k1_pubkey_sort(CTX, pks_ptr, 0) == 1); + /* Test illegal public keys */ + memset(&pks[0], 0, sizeof(pks[0])); + CHECK_ILLEGAL_VOID(CTX, CHECK(secp256k1_pubkey_sort(CTX, pks_ptr, 2) == 1)); + memset(&pks[1], 0, sizeof(pks[1])); + { + int32_t ecount = 0; + secp256k1_context_set_illegal_callback(CTX, counting_callback_fn, &ecount); + CHECK(secp256k1_pubkey_sort(CTX, pks_ptr, 2) == 1); + CHECK(ecount == 2); + secp256k1_context_set_illegal_callback(CTX, NULL, NULL); + } +} + +static void test_sort(void) { + secp256k1_pubkey pk[5]; + unsigned char pk_ser[5][33] = { + { 0x02, 0x08 }, + { 0x02, 0x0b }, + { 0x02, 0x0c }, + { 0x03, 0x05 }, + { 0x03, 0x0a }, + }; + int i; + size_t pk_order[5] = { 0, 1, 2, 3, 4 }; + + for (i = 0; i < 5; i++) { + CHECK(secp256k1_ec_pubkey_parse(CTX, &pk[i], pk_ser[i], sizeof(pk_ser[i]))); + } + + permute(pk_order, 1); + test_sort_helper(pk, pk_order, 1); + permute(pk_order, 2); + test_sort_helper(pk, pk_order, 2); + permute(pk_order, 3); + test_sort_helper(pk, pk_order, 3); + for (i = 0; i < COUNT; i++) { + permute(pk_order, 4); + test_sort_helper(pk, pk_order, 4); + } + for (i = 0; i < COUNT; i++) { + permute(pk_order, 5); + test_sort_helper(pk, pk_order, 5); + } + /* Check that sorting also works for random pubkeys */ + for (i = 0; i < COUNT; i++) { + int j; + const secp256k1_pubkey *pk_ptr[5]; + for (j = 0; j < 5; j++) { + rand_pk(&pk[j]); + pk_ptr[j] = &pk[j]; + } + secp256k1_pubkey_sort(CTX, pk_ptr, 5); + for (j = 1; j < 5; j++) { + CHECK(secp256k1_pubkey_sort_cmp(&pk_ptr[j - 1], &pk_ptr[j], CTX) <= 0); + } + } +} + +/* Test vectors from BIP-MuSig2 */ +static void test_sort_vectors(void) { + enum { N_PUBKEYS = 6 }; + unsigned char pk_ser[N_PUBKEYS][33] = { + { 0x02, 0xDD, 0x30, 0x8A, 0xFE, 0xC5, 0x77, 0x7E, 0x13, 0x12, 0x1F, + 0xA7, 0x2B, 0x9C, 0xC1, 0xB7, 0xCC, 0x01, 0x39, 0x71, 0x53, 0x09, + 0xB0, 0x86, 0xC9, 0x60, 0xE1, 0x8F, 0xD9, 0x69, 0x77, 0x4E, 0xB8 }, + { 0x02, 0xF9, 0x30, 0x8A, 0x01, 0x92, 0x58, 0xC3, 0x10, 0x49, 0x34, + 0x4F, 0x85, 0xF8, 0x9D, 0x52, 0x29, 0xB5, 0x31, 0xC8, 0x45, 0x83, + 0x6F, 0x99, 0xB0, 0x86, 0x01, 0xF1, 0x13, 0xBC, 0xE0, 0x36, 0xF9 }, + { 0x03, 0xDF, 0xF1, 0xD7, 0x7F, 0x2A, 0x67, 0x1C, 0x5F, 0x36, 0x18, + 0x37, 0x26, 0xDB, 0x23, 0x41, 0xBE, 0x58, 0xFE, 0xAE, 0x1D, 0xA2, + 0xDE, 0xCE, 0xD8, 0x43, 0x24, 0x0F, 0x7B, 0x50, 0x2B, 0xA6, 0x59 }, + { 0x02, 0x35, 0x90, 0xA9, 0x4E, 0x76, 0x8F, 0x8E, 0x18, 0x15, 0xC2, + 0xF2, 0x4B, 0x4D, 0x80, 0xA8, 0xE3, 0x14, 0x93, 0x16, 0xC3, 0x51, + 0x8C, 0xE7, 0xB7, 0xAD, 0x33, 0x83, 0x68, 0xD0, 0x38, 0xCA, 0x66 }, + { 0x02, 0xDD, 0x30, 0x8A, 0xFE, 0xC5, 0x77, 0x7E, 0x13, 0x12, 0x1F, + 0xA7, 0x2B, 0x9C, 0xC1, 0xB7, 0xCC, 0x01, 0x39, 0x71, 0x53, 0x09, + 0xB0, 0x86, 0xC9, 0x60, 0xE1, 0x8F, 0xD9, 0x69, 0x77, 0x4E, 0xFF }, + { 0x02, 0xDD, 0x30, 0x8A, 0xFE, 0xC5, 0x77, 0x7E, 0x13, 0x12, 0x1F, + 0xA7, 0x2B, 0x9C, 0xC1, 0xB7, 0xCC, 0x01, 0x39, 0x71, 0x53, 0x09, + 0xB0, 0x86, 0xC9, 0x60, 0xE1, 0x8F, 0xD9, 0x69, 0x77, 0x4E, 0xB8 } + }; + secp256k1_pubkey pubkeys[N_PUBKEYS]; + secp256k1_pubkey *sorted[N_PUBKEYS]; + const secp256k1_pubkey *pks_ptr[N_PUBKEYS]; + int i; + + sorted[0] = &pubkeys[3]; + sorted[1] = &pubkeys[0]; + sorted[2] = &pubkeys[0]; + sorted[3] = &pubkeys[4]; + sorted[4] = &pubkeys[1]; + sorted[5] = &pubkeys[2]; + + for (i = 0; i < N_PUBKEYS; i++) { + CHECK(secp256k1_ec_pubkey_parse(CTX, &pubkeys[i], pk_ser[i], sizeof(pk_ser[i]))); + pks_ptr[i] = &pubkeys[i]; + } + CHECK(secp256k1_pubkey_sort(CTX, pks_ptr, N_PUBKEYS) == 1); + for (i = 0; i < N_PUBKEYS; i++) { + CHECK(secp256k1_memcmp_var(pks_ptr[i], sorted[i], sizeof(secp256k1_pubkey)) == 0); + } +} + static void run_extrakeys_tests(void) { /* xonly key test cases */ test_xonly_pubkey(); @@ -478,6 +666,12 @@ static void run_extrakeys_tests(void) { /* keypair tests */ test_keypair(); test_keypair_add(); + + /* sorting tests */ + test_hsort(); + test_sort_api(); + test_sort(); + test_sort_vectors(); } #endif