OpenCoverage

constant_time_locl.h

Absolute File Name:/home/opencoverage/opencoverage/guest-scripts/libressl/src/crypto/constant_time_locl.h
Source codeSwitch to Preprocessed file
LineSourceCount
1/* crypto/constant_time_locl.h */-
2/*--
3 * Utilities for constant-time cryptography.-
4 *-
5 * Author: Emilia Kasper (emilia@openssl.org)-
6 * Based on previous work by Bodo Moeller, Emilia Kasper, Adam Langley-
7 * (Google).-
8 * ====================================================================-
9 * Copyright (c) 2014 The OpenSSL Project. All rights reserved.-
10 *-
11 * Redistribution and use in source and binary forms, with or without-
12 * modification, are permitted provided that the following conditions-
13 * are met:-
14 * 1. Redistributions of source code must retain the copyright-
15 * notice, this list of conditions and the following disclaimer.-
16 * 2. Redistributions in binary form must reproduce the above copyright-
17 * notice, this list of conditions and the following disclaimer in the-
18 * documentation and/or other materials provided with the distribution.-
19 * 3. All advertising materials mentioning features or use of this software-
20 * must display the following acknowledgement:-
21 * "This product includes cryptographic software written by-
22 * Eric Young (eay@cryptsoft.com)"-
23 * The word 'cryptographic' can be left out if the rouines from the library-
24 * being used are not cryptographic related :-).-
25 * 4. If you include any Windows specific code (or a derivative thereof) from-
26 * the apps directory (application code) you must include an acknowledgement:-
27 * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"-
28 *-
29 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND-
30 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE-
31 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE-
32 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE-
33 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL-
34 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS-
35 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)-
36 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT-
37 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY-
38 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF-
39 * SUCH DAMAGE.-
40 *-
41 * The licence and distribution terms for any publically available version or-
42 * derivative of this code cannot be changed. i.e. this code cannot simply be-
43 * copied and put under another distribution licence-
44 * [including the GNU Public Licence.]-
45 */-
46-
47#ifndef HEADER_CONSTANT_TIME_LOCL_H-
48# define HEADER_CONSTANT_TIME_LOCL_H-
49-
50__BEGIN_HIDDEN_DECLS-
51-
52/*--
53 * The boolean methods return a bitmask of all ones (0xff...f) for true-
54 * and 0 for false. This is useful for choosing a value based on the result-
55 * of a conditional in constant time. For example,-
56 *-
57 * if (a < b) {-
58 * c = a;-
59 * } else {-
60 * c = b;-
61 * }-
62 *-
63 * can be written as-
64 *-
65 * unsigned int lt = constant_time_lt(a, b);-
66 * c = constant_time_select(lt, a, b);-
67 */-
68-
69/*-
70 * Returns the given value with the MSB copied to all the other-
71 * bits. Uses the fact that arithmetic shift shifts-in the sign bit.-
72 * However, this is not ensured by the C standard so you may need to-
73 * replace this with something else on odd CPUs.-
74 */-
75static inline unsigned int constant_time_msb(unsigned int a);-
76-
77/*-
78 * Returns 0xff..f if a < b and 0 otherwise.-
79 */-
80static inline unsigned int constant_time_lt(unsigned int a, unsigned int b);-
81/* Convenience method for getting an 8-bit mask. */-
82static inline unsigned char constant_time_lt_8(unsigned int a,-
83 unsigned int b);-
84-
85/*-
86 * Returns 0xff..f if a >= b and 0 otherwise.-
87 */-
88static inline unsigned int constant_time_ge(unsigned int a, unsigned int b);-
89/* Convenience method for getting an 8-bit mask. */-
90static inline unsigned char constant_time_ge_8(unsigned int a,-
91 unsigned int b);-
92-
93/*-
94 * Returns 0xff..f if a == 0 and 0 otherwise.-
95 */-
96static inline unsigned int constant_time_is_zero(unsigned int a);-
97/* Convenience method for getting an 8-bit mask. */-
98static inline unsigned char constant_time_is_zero_8(unsigned int a);-
99-
100/*-
101 * Returns 0xff..f if a == b and 0 otherwise.-
102 */-
103static inline unsigned int constant_time_eq(unsigned int a, unsigned int b);-
104/* Convenience method for getting an 8-bit mask. */-
105static inline unsigned char constant_time_eq_8(unsigned int a,-
106 unsigned int b);-
107/* Signed integers. */-
108static inline unsigned int constant_time_eq_int(int a, int b);-
109/* Convenience method for getting an 8-bit mask. */-
110static inline unsigned char constant_time_eq_int_8(int a, int b);-
111-
112/*--
113 * Returns (mask & a) | (~mask & b).-
114 *-
115 * When |mask| is all 1s or all 0s (as returned by the methods above),-
116 * the select methods return either |a| (if |mask| is nonzero) or |b|-
117 * (if |mask| is zero).-
118 */-
119static inline unsigned int constant_time_select(unsigned int mask,-
120 unsigned int a,-
121 unsigned int b);-
122/* Convenience method for unsigned chars. */-
123static inline unsigned char constant_time_select_8(unsigned char mask,-
124 unsigned char a,-
125 unsigned char b);-
126/* Convenience method for signed integers. */-
127static inline int constant_time_select_int(unsigned int mask, int a, int b);-
128-
129static inline unsigned int constant_time_msb(unsigned int a)-
130{-
131 return 0 - (a >> (sizeof(a) * 8 - 1));
executed 2657590 times by 12 tests: return 0 - (a >> (sizeof(a) * 8 - 1));
Executed by:
  • bntest
  • dhtest
  • dsatest
  • ectest
  • exptest
  • libcrypto.so.44.0.1
  • mont
  • pkcs7test
  • rsa_test
  • servertest
  • ssltest
  • tlstest
2657590
132}-
133-
134static inline unsigned int constant_time_lt(unsigned int a, unsigned int b)-
135{-
136 return constant_time_msb(a ^ ((a ^ b) | ((a - b) ^ b)));
never executed: return constant_time_msb(a ^ ((a ^ b) | ((a - b) ^ b)));
0
137}-
138-
139static inline unsigned char constant_time_lt_8(unsigned int a, unsigned int b)-
140{-
141 return (unsigned char)(constant_time_lt(a, b));
never executed: return (unsigned char)(constant_time_lt(a, b));
0
142}-
143-
144static inline unsigned int constant_time_ge(unsigned int a, unsigned int b)-
145{-
146 return ~constant_time_lt(a, b);
never executed: return ~constant_time_lt(a, b);
0
147}-
148-
149static inline unsigned char constant_time_ge_8(unsigned int a, unsigned int b)-
150{-
151 return (unsigned char)(constant_time_ge(a, b));
never executed: return (unsigned char)(constant_time_ge(a, b));
0
152}-
153-
154static inline unsigned int constant_time_is_zero(unsigned int a)-
155{-
156 return constant_time_msb(~a & (a - 1));
executed 2657590 times by 12 tests: return constant_time_msb(~a & (a - 1));
Executed by:
  • bntest
  • dhtest
  • dsatest
  • ectest
  • exptest
  • libcrypto.so.44.0.1
  • mont
  • pkcs7test
  • rsa_test
  • servertest
  • ssltest
  • tlstest
2657590
157}-
158-
159static inline unsigned char constant_time_is_zero_8(unsigned int a)-
160{-
161 return (unsigned char)(constant_time_is_zero(a));
never executed: return (unsigned char)(constant_time_is_zero(a));
0
162}-
163-
164static inline unsigned int constant_time_eq(unsigned int a, unsigned int b)-
165{-
166 return constant_time_is_zero(a ^ b);
executed 2657590 times by 12 tests: return constant_time_is_zero(a ^ b);
Executed by:
  • bntest
  • dhtest
  • dsatest
  • ectest
  • exptest
  • libcrypto.so.44.0.1
  • mont
  • pkcs7test
  • rsa_test
  • servertest
  • ssltest
  • tlstest
2657590
167}-
168-
169static inline unsigned char constant_time_eq_8(unsigned int a, unsigned int b)-
170{-
171 return (unsigned char)(constant_time_eq(a, b));
never executed: return (unsigned char)(constant_time_eq(a, b));
0
172}-
173-
174static inline unsigned int constant_time_eq_int(int a, int b)-
175{-
176 return constant_time_eq((unsigned)(a), (unsigned)(b));
executed 2657590 times by 12 tests: return constant_time_eq((unsigned)(a), (unsigned)(b));
Executed by:
  • bntest
  • dhtest
  • dsatest
  • ectest
  • exptest
  • libcrypto.so.44.0.1
  • mont
  • pkcs7test
  • rsa_test
  • servertest
  • ssltest
  • tlstest
2657590
177}-
178-
179static inline unsigned char constant_time_eq_int_8(int a, int b)-
180{-
181 return constant_time_eq_8((unsigned)(a), (unsigned)(b));
never executed: return constant_time_eq_8((unsigned)(a), (unsigned)(b));
0
182}-
183-
184static inline unsigned int constant_time_select(unsigned int mask,-
185 unsigned int a,-
186 unsigned int b)-
187{-
188 return (mask & a) | (~mask & b);
never executed: return (mask & a) | (~mask & b);
0
189}-
190-
191static inline unsigned char constant_time_select_8(unsigned char mask,-
192 unsigned char a,-
193 unsigned char b)-
194{-
195 return (unsigned char)(constant_time_select(mask, a, b));
never executed: return (unsigned char)(constant_time_select(mask, a, b));
0
196}-
197-
198static inline int constant_time_select_int(unsigned int mask, int a, int b)-
199{-
200 return (int)(constant_time_select(mask, (unsigned)(a), (unsigned)(b)));
never executed: return (int)(constant_time_select(mask, (unsigned)(a), (unsigned)(b)));
0
201}-
202-
203__END_HIDDEN_DECLS-
204-
205#endif /* HEADER_CONSTANT_TIME_LOCL_H */-
Source codeSwitch to Preprocessed file
Generated by Squish Coco 4.2.2