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Diffstat (limited to 'src/lib/libcrypto/bn/bn_shift.c')
-rw-r--r-- | src/lib/libcrypto/bn/bn_shift.c | 175 |
1 files changed, 0 insertions, 175 deletions
diff --git a/src/lib/libcrypto/bn/bn_shift.c b/src/lib/libcrypto/bn/bn_shift.c deleted file mode 100644 index 12edc7c0a0..0000000000 --- a/src/lib/libcrypto/bn/bn_shift.c +++ /dev/null | |||
@@ -1,175 +0,0 @@ | |||
1 | /* $OpenBSD: bn_shift.c,v 1.22 2023/07/08 12:21:58 beck Exp $ */ | ||
2 | /* | ||
3 | * Copyright (c) 2022, 2023 Joel Sing <jsing@openbsd.org> | ||
4 | * | ||
5 | * Permission to use, copy, modify, and distribute this software for any | ||
6 | * purpose with or without fee is hereby granted, provided that the above | ||
7 | * copyright notice and this permission notice appear in all copies. | ||
8 | * | ||
9 | * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES | ||
10 | * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF | ||
11 | * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR | ||
12 | * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES | ||
13 | * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN | ||
14 | * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF | ||
15 | * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. | ||
16 | */ | ||
17 | |||
18 | #include <openssl/bn.h> | ||
19 | #include <openssl/err.h> | ||
20 | |||
21 | #include "bn_local.h" | ||
22 | |||
23 | static inline int | ||
24 | bn_lshift(BIGNUM *r, const BIGNUM *a, int n) | ||
25 | { | ||
26 | size_t count, shift_bits, shift_words; | ||
27 | size_t lshift, rshift; | ||
28 | ssize_t rstride; | ||
29 | BN_ULONG *dst, *src; | ||
30 | |||
31 | if (n < 0) { | ||
32 | BNerror(BN_R_INVALID_LENGTH); | ||
33 | return 0; | ||
34 | } | ||
35 | shift_bits = n; | ||
36 | |||
37 | /* | ||
38 | * Left bit shift, potentially across word boundaries. | ||
39 | * | ||
40 | * When shift is not an exact multiple of BN_BITS2, the bottom bits of | ||
41 | * the previous word need to be right shifted and combined with the left | ||
42 | * shifted bits using bitwise OR. If shift is an exact multiple of | ||
43 | * BN_BITS2, the source for the left and right shifts are the same | ||
44 | * and the shifts become zero bits (which is effectively a memmove). | ||
45 | */ | ||
46 | shift_words = shift_bits / BN_BITS2; | ||
47 | lshift = shift_bits % BN_BITS2; | ||
48 | rshift = (BN_BITS2 - lshift) % BN_BITS2; | ||
49 | rstride = 0 - (lshift + rshift) / BN_BITS2; | ||
50 | |||
51 | if (a->top < 1) { | ||
52 | BN_zero(r); | ||
53 | return 1; | ||
54 | } | ||
55 | |||
56 | count = a->top + shift_words + 1; | ||
57 | |||
58 | if (count < shift_words) | ||
59 | return 0; | ||
60 | |||
61 | if (!bn_wexpand(r, count)) | ||
62 | return 0; | ||
63 | |||
64 | src = a->d + a->top - 1; | ||
65 | dst = r->d + a->top + shift_words; | ||
66 | |||
67 | /* Handle right shift for top most word. */ | ||
68 | *dst = (*src >> rshift) & rstride; | ||
69 | dst--; | ||
70 | |||
71 | /* Handle left shift and right shift for remaining words. */ | ||
72 | while (src > a->d) { | ||
73 | *dst = *src << lshift | src[rstride] >> rshift; | ||
74 | src--; | ||
75 | dst--; | ||
76 | } | ||
77 | *dst = *src << lshift; | ||
78 | |||
79 | /* Zero any additional words resulting from the left shift. */ | ||
80 | while (dst > r->d) { | ||
81 | dst--; | ||
82 | *dst = 0; | ||
83 | } | ||
84 | |||
85 | r->top = count; | ||
86 | bn_correct_top(r); | ||
87 | |||
88 | BN_set_negative(r, a->neg); | ||
89 | |||
90 | return 1; | ||
91 | } | ||
92 | |||
93 | static inline int | ||
94 | bn_rshift(BIGNUM *r, const BIGNUM *a, int n) | ||
95 | { | ||
96 | size_t count, shift_bits, shift_words; | ||
97 | size_t lshift, rshift; | ||
98 | ssize_t lstride; | ||
99 | BN_ULONG *dst, *src; | ||
100 | size_t i; | ||
101 | |||
102 | if (n < 0) { | ||
103 | BNerror(BN_R_INVALID_LENGTH); | ||
104 | return 0; | ||
105 | } | ||
106 | shift_bits = n; | ||
107 | |||
108 | /* | ||
109 | * Right bit shift, potentially across word boundaries. | ||
110 | * | ||
111 | * When shift is not an exact multiple of BN_BITS2, the top bits of | ||
112 | * the next word need to be left shifted and combined with the right | ||
113 | * shifted bits using bitwise OR. If shift is an exact multiple of | ||
114 | * BN_BITS2, the source for the left and right shifts are the same | ||
115 | * and the shifts become zero (which is effectively a memmove). | ||
116 | */ | ||
117 | shift_words = shift_bits / BN_BITS2; | ||
118 | rshift = shift_bits % BN_BITS2; | ||
119 | lshift = (BN_BITS2 - rshift) % BN_BITS2; | ||
120 | lstride = (lshift + rshift) / BN_BITS2; | ||
121 | |||
122 | if (a->top <= shift_words) { | ||
123 | BN_zero(r); | ||
124 | return 1; | ||
125 | } | ||
126 | count = a->top - shift_words; | ||
127 | |||
128 | if (!bn_wexpand(r, count)) | ||
129 | return 0; | ||
130 | |||
131 | src = a->d + shift_words; | ||
132 | dst = r->d; | ||
133 | |||
134 | for (i = 1; i < count; i++) { | ||
135 | *dst = src[lstride] << lshift | *src >> rshift; | ||
136 | src++; | ||
137 | dst++; | ||
138 | } | ||
139 | *dst = *src >> rshift; | ||
140 | |||
141 | r->top = count; | ||
142 | bn_correct_top(r); | ||
143 | |||
144 | BN_set_negative(r, a->neg); | ||
145 | |||
146 | return 1; | ||
147 | } | ||
148 | |||
149 | int | ||
150 | BN_lshift1(BIGNUM *r, const BIGNUM *a) | ||
151 | { | ||
152 | return bn_lshift(r, a, 1); | ||
153 | } | ||
154 | LCRYPTO_ALIAS(BN_lshift1); | ||
155 | |||
156 | int | ||
157 | BN_lshift(BIGNUM *r, const BIGNUM *a, int n) | ||
158 | { | ||
159 | return bn_lshift(r, a, n); | ||
160 | } | ||
161 | LCRYPTO_ALIAS(BN_lshift); | ||
162 | |||
163 | int | ||
164 | BN_rshift1(BIGNUM *r, const BIGNUM *a) | ||
165 | { | ||
166 | return bn_rshift(r, a, 1); | ||
167 | } | ||
168 | LCRYPTO_ALIAS(BN_rshift1); | ||
169 | |||
170 | int | ||
171 | BN_rshift(BIGNUM *r, const BIGNUM *a, int n) | ||
172 | { | ||
173 | return bn_rshift(r, a, n); | ||
174 | } | ||
175 | LCRYPTO_ALIAS(BN_rshift); | ||