1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Copyright 2025 Google LLC 4 */ 5 #include <crypto/poly1305.h> 6 #include "poly1305-testvecs.h" 7 8 /* 9 * A fixed key used when presenting Poly1305 as an unkeyed hash function in 10 * order to reuse hash-test-template.h. At the beginning of the test suite, 11 * this is initialized to bytes generated from a fixed seed. 12 */ 13 static u8 test_key[POLY1305_KEY_SIZE]; 14 15 /* This probably should be in the actual API, but just define it here for now */ 16 static void poly1305(const u8 key[POLY1305_KEY_SIZE], const u8 *data, 17 size_t len, u8 out[POLY1305_DIGEST_SIZE]) 18 { 19 struct poly1305_desc_ctx ctx; 20 21 poly1305_init(&ctx, key); 22 poly1305_update(&ctx, data, len); 23 poly1305_final(&ctx, out); 24 } 25 26 static void poly1305_init_withtestkey(struct poly1305_desc_ctx *ctx) 27 { 28 poly1305_init(ctx, test_key); 29 } 30 31 static void poly1305_withtestkey(const u8 *data, size_t len, 32 u8 out[POLY1305_DIGEST_SIZE]) 33 { 34 poly1305(test_key, data, len, out); 35 } 36 37 /* Generate the HASH_KUNIT_CASES using hash-test-template.h. */ 38 #define HASH poly1305_withtestkey 39 #define HASH_CTX poly1305_desc_ctx 40 #define HASH_SIZE POLY1305_DIGEST_SIZE 41 #define HASH_INIT poly1305_init_withtestkey 42 #define HASH_UPDATE poly1305_update 43 #define HASH_FINAL poly1305_final 44 #include "hash-test-template.h" 45 46 static int poly1305_suite_init(struct kunit_suite *suite) 47 { 48 rand_bytes_seeded_from_len(test_key, POLY1305_KEY_SIZE); 49 return hash_suite_init(suite); 50 } 51 52 static void poly1305_suite_exit(struct kunit_suite *suite) 53 { 54 hash_suite_exit(suite); 55 } 56 57 /* 58 * Poly1305 test case which uses a key and message consisting only of one bits: 59 * 60 * - Using an all-one-bits r_key tests the key clamping. 61 * - Using an all-one-bits s_key tests carries in implementations of the 62 * addition mod 2**128 during finalization. 63 * - Using all-one-bits message, and to a lesser extent r_key, tends to maximize 64 * any intermediate accumulator values. This increases the chance of 65 * detecting bugs that occur only in rare cases where the accumulator values 66 * get very large, for example the bug fixed by commit 678cce4019d746da 67 * ("crypto: x86/poly1305 - fix overflow during partial reduction"). 68 * 69 * Accumulator overflow bugs may be specific to particular update lengths (in 70 * blocks) and/or particular values of the previous acculumator. Note that the 71 * accumulator starts at 0 which gives the lowest chance of an overflow. Thus, 72 * a single all-one-bits test vector may be insufficient. 73 * 74 * Considering that, do the following test: continuously update a single 75 * Poly1305 context with all-one-bits data of varying lengths (0, 16, 32, ..., 76 * 4096 bytes). After each update, generate the MAC from the current context, 77 * and feed that MAC into a separate Poly1305 context. Repeat that entire 78 * sequence of updates 32 times without re-initializing either context, 79 * resulting in a total of 8224 MAC computations from a long-running, cumulative 80 * context. Finally, generate and verify the MAC of all the MACs. 81 */ 82 static void test_poly1305_allones_keys_and_message(struct kunit *test) 83 { 84 struct poly1305_desc_ctx mac_ctx, macofmacs_ctx; 85 u8 mac[POLY1305_DIGEST_SIZE]; 86 87 static_assert(TEST_BUF_LEN >= 4096); 88 memset(test_buf, 0xff, 4096); 89 90 poly1305_init(&mac_ctx, test_buf); 91 poly1305_init(&macofmacs_ctx, test_buf); 92 for (int i = 0; i < 32; i++) { 93 for (size_t len = 0; len <= 4096; len += 16) { 94 struct poly1305_desc_ctx tmp_ctx; 95 96 poly1305_update(&mac_ctx, test_buf, len); 97 tmp_ctx = mac_ctx; 98 poly1305_final(&tmp_ctx, mac); 99 poly1305_update(&macofmacs_ctx, mac, 100 POLY1305_DIGEST_SIZE); 101 } 102 } 103 poly1305_final(&macofmacs_ctx, mac); 104 KUNIT_ASSERT_MEMEQ(test, mac, poly1305_allones_macofmacs, 105 POLY1305_DIGEST_SIZE); 106 } 107 108 /* 109 * Poly1305 test case which uses r_key=1, s_key=0, and a 48-byte message 110 * consisting of three blocks with integer values [2**128 - i, 0, 0]. In this 111 * case, the result of the polynomial evaluation is 2**130 - i. For small 112 * values of i, this is very close to the modulus 2**130 - 5, which helps catch 113 * edge case bugs in the modular reduction logic. 114 */ 115 static void test_poly1305_reduction_edge_cases(struct kunit *test) 116 { 117 static const u8 key[POLY1305_KEY_SIZE] = { 1 }; /* r_key=1, s_key=0 */ 118 u8 data[3 * POLY1305_BLOCK_SIZE] = {}; 119 u8 expected_mac[POLY1305_DIGEST_SIZE]; 120 u8 actual_mac[POLY1305_DIGEST_SIZE]; 121 122 for (int i = 1; i <= 10; i++) { 123 /* Set the first data block to 2**128 - i. */ 124 data[0] = -i; 125 memset(&data[1], 0xff, POLY1305_BLOCK_SIZE - 1); 126 127 /* 128 * Assuming s_key=0, the expected MAC as an integer is 129 * (2**130 - i mod 2**130 - 5) + 0 mod 2**128. If 1 <= i <= 5, 130 * that's 5 - i. If 6 <= i <= 10, that's 2**128 - i. 131 */ 132 if (i <= 5) { 133 expected_mac[0] = 5 - i; 134 memset(&expected_mac[1], 0, POLY1305_DIGEST_SIZE - 1); 135 } else { 136 expected_mac[0] = -i; 137 memset(&expected_mac[1], 0xff, 138 POLY1305_DIGEST_SIZE - 1); 139 } 140 141 /* Compute and verify the MAC. */ 142 poly1305(key, data, sizeof(data), actual_mac); 143 KUNIT_ASSERT_MEMEQ(test, actual_mac, expected_mac, 144 POLY1305_DIGEST_SIZE); 145 } 146 } 147 148 static struct kunit_case poly1305_test_cases[] = { 149 HASH_KUNIT_CASES, 150 KUNIT_CASE(test_poly1305_allones_keys_and_message), 151 KUNIT_CASE(test_poly1305_reduction_edge_cases), 152 KUNIT_CASE(benchmark_hash), 153 {}, 154 }; 155 156 static struct kunit_suite poly1305_test_suite = { 157 .name = "poly1305", 158 .test_cases = poly1305_test_cases, 159 .suite_init = poly1305_suite_init, 160 .suite_exit = poly1305_suite_exit, 161 }; 162 kunit_test_suite(poly1305_test_suite); 163 164 MODULE_DESCRIPTION("KUnit tests and benchmark for Poly1305"); 165 MODULE_LICENSE("GPL"); 166