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c38bb727 BL |
1 | /* |
2 | * Copyright 2016 The OpenSSL Project Authors. All Rights Reserved. | |
3 | * | |
4 | * Licensed under the OpenSSL licenses, (the "License"); | |
5 | * you may not use this file except in compliance with the License. | |
6 | * You may obtain a copy of the License at | |
7 | * https://www.openssl.org/source/license.html | |
8 | * or in the file LICENSE in the source distribution. | |
9 | */ | |
10 | ||
11 | /* | |
12 | * Confirm that if (d, r) = a / b, then b * d + r == a, and that sign(d) == | |
13 | * sign(a), and 0 <= r <= b | |
14 | */ | |
15 | ||
16 | #include <stdio.h> | |
17 | #include <openssl/bn.h> | |
d69d8f90 | 18 | #include <openssl/err.h> |
c38bb727 BL |
19 | #include "fuzzer.h" |
20 | ||
61389f09 | 21 | /* 256 kB */ |
22 | #define MAX_LEN (256 * 1000) | |
23 | ||
8087bcb3 KR |
24 | static BN_CTX *ctx; |
25 | static BIGNUM *b1; | |
26 | static BIGNUM *b2; | |
27 | static BIGNUM *b3; | |
28 | static BIGNUM *b4; | |
29 | static BIGNUM *b5; | |
30 | ||
f3e911d5 KR |
31 | int FuzzerInitialize(int *argc, char ***argv) |
32 | { | |
8087bcb3 KR |
33 | b1 = BN_new(); |
34 | b2 = BN_new(); | |
35 | b3 = BN_new(); | |
36 | b4 = BN_new(); | |
37 | b5 = BN_new(); | |
38 | ctx = BN_CTX_new(); | |
39 | ||
d69d8f90 KR |
40 | OPENSSL_init_crypto(OPENSSL_INIT_LOAD_CRYPTO_STRINGS, NULL); |
41 | ERR_get_state(); | |
42 | ||
90d28f05 BL |
43 | return 1; |
44 | } | |
45 | ||
f3e911d5 KR |
46 | int FuzzerTestOneInput(const uint8_t *buf, size_t len) |
47 | { | |
90d28f05 BL |
48 | int success = 0; |
49 | size_t l1 = 0, l2 = 0; | |
50 | /* s1 and s2 will be the signs for b1 and b2. */ | |
51 | int s1 = 0, s2 = 0; | |
c38bb727 | 52 | |
61389f09 | 53 | /* limit the size of the input to avoid timeout */ |
54 | if (len > MAX_LEN) | |
55 | len = MAX_LEN; | |
56 | ||
90d28f05 BL |
57 | /* We are going to split the buffer in two, sizes l1 and l2, giving b1 and |
58 | * b2. | |
59 | */ | |
c38bb727 BL |
60 | if (len > 0) { |
61 | --len; | |
90d28f05 BL |
62 | /* Use first byte to divide the remaining buffer into 3Fths. I admit |
63 | * this disallows some number sizes. If it matters, better ideas are | |
64 | * welcome (Ben). | |
65 | */ | |
c38bb727 BL |
66 | l1 = ((buf[0] & 0x3f) * len) / 0x3f; |
67 | s1 = buf[0] & 0x40; | |
68 | s2 = buf[0] & 0x80; | |
69 | ++buf; | |
70 | l2 = len - l1; | |
71 | } | |
72 | OPENSSL_assert(BN_bin2bn(buf, l1, b1) == b1); | |
73 | BN_set_negative(b1, s1); | |
74 | OPENSSL_assert(BN_bin2bn(buf + l1, l2, b2) == b2); | |
75 | BN_set_negative(b2, s2); | |
76 | ||
90d28f05 | 77 | /* divide by 0 is an error */ |
c38bb727 BL |
78 | if (BN_is_zero(b2)) { |
79 | success = 1; | |
80 | goto done; | |
81 | } | |
82 | ||
83 | OPENSSL_assert(BN_div(b3, b4, b1, b2, ctx)); | |
84 | if (BN_is_zero(b1)) | |
85 | success = BN_is_zero(b3) && BN_is_zero(b4); | |
86 | else if (BN_is_negative(b1)) | |
87 | success = (BN_is_negative(b3) != BN_is_negative(b2) || BN_is_zero(b3)) | |
88 | && (BN_is_negative(b4) || BN_is_zero(b4)); | |
89 | else | |
90 | success = (BN_is_negative(b3) == BN_is_negative(b2) || BN_is_zero(b3)) | |
91 | && (!BN_is_negative(b4) || BN_is_zero(b4)); | |
92 | OPENSSL_assert(BN_mul(b5, b3, b2, ctx)); | |
93 | OPENSSL_assert(BN_add(b5, b5, b4)); | |
94 | ||
95 | success = success && BN_cmp(b5, b1) == 0; | |
96 | if (!success) { | |
97 | BN_print_fp(stdout, b1); | |
98 | putchar('\n'); | |
99 | BN_print_fp(stdout, b2); | |
100 | putchar('\n'); | |
101 | BN_print_fp(stdout, b3); | |
102 | putchar('\n'); | |
103 | BN_print_fp(stdout, b4); | |
104 | putchar('\n'); | |
105 | BN_print_fp(stdout, b5); | |
106 | putchar('\n'); | |
107 | printf("%d %d %d %d %d %d %d\n", BN_is_negative(b1), | |
108 | BN_is_negative(b2), | |
109 | BN_is_negative(b3), BN_is_negative(b4), BN_is_zero(b4), | |
110 | BN_is_negative(b3) != BN_is_negative(b2) | |
111 | && (BN_is_negative(b4) || BN_is_zero(b4)), | |
112 | BN_cmp(b5, b1)); | |
113 | puts("----\n"); | |
114 | } | |
115 | ||
116 | done: | |
117 | OPENSSL_assert(success); | |
d69d8f90 | 118 | ERR_clear_error(); |
c38bb727 BL |
119 | |
120 | return 0; | |
121 | } | |
ad4da7fb KR |
122 | |
123 | void FuzzerCleanup(void) | |
124 | { | |
8087bcb3 KR |
125 | BN_free(b1); |
126 | BN_free(b2); | |
127 | BN_free(b3); | |
128 | BN_free(b4); | |
129 | BN_free(b5); | |
130 | BN_CTX_free(ctx); | |
ad4da7fb | 131 | } |