1 /*
2 * Copyright 1998-2023 The OpenSSL Project Authors. All Rights Reserved.
3 *
4 * Licensed under the Apache License 2.0 (the "License"). You may not use
5 * this file except in compliance with the License. You can obtain a copy
6 * in the file LICENSE in the source distribution or at
7 * https://www.openssl.org/source/license.html
8 */
9
10 #include "internal/e_os.h"
11 #include "crypto/cryptlib.h"
12
13 #if defined(__i386) || defined(__i386__) || defined(_M_IX86) || \
14 defined(__x86_64) || defined(__x86_64__) || \
15 defined(_M_AMD64) || defined(_M_X64)
16
17 extern unsigned int OPENSSL_ia32cap_P[OPENSSL_IA32CAP_P_MAX_INDEXES];
18
19 # if defined(OPENSSL_CPUID_OBJ)
20
21 /*
22 * Purpose of these minimalistic and character-type-agnostic subroutines
23 * is to break dependency on MSVCRT (on Windows) and locale. This makes
24 * OPENSSL_cpuid_setup safe to use as "constructor". "Character-type-
25 * agnostic" means that they work with either wide or 8-bit characters,
26 * exploiting the fact that first 127 characters can be simply casted
27 * between the sets, while the rest would be simply rejected by ossl_is*
28 * subroutines.
29 */
30 # ifdef _WIN32
31 typedef WCHAR variant_char;
32 # define OPENSSL_IA32CAP_P_MAX_CHAR_SIZE 256
ossl_getenv(const char * name)33 static variant_char *ossl_getenv(const char *name)
34 {
35 /*
36 * Since we pull only one environment variable, it's simpler to
37 * just ignore |name| and use equivalent wide-char L-literal.
38 * As well as to ignore excessively long values...
39 */
40 static WCHAR value[OPENSSL_IA32CAP_P_MAX_CHAR_SIZE];
41 DWORD len = GetEnvironmentVariableW(L"OPENSSL_ia32cap", value, OPENSSL_IA32CAP_P_MAX_CHAR_SIZE);
42
43 return (len > 0 && len < OPENSSL_IA32CAP_P_MAX_CHAR_SIZE) ? value : NULL;
44 }
45 # else
46 typedef char variant_char;
47 # define ossl_getenv getenv
48 # endif
49
50 # include "crypto/ctype.h"
51
todigit(variant_char c)52 static int todigit(variant_char c)
53 {
54 if (ossl_isdigit(c))
55 return c - '0';
56 else if (ossl_isxdigit(c))
57 return ossl_tolower(c) - 'a' + 10;
58
59 /* return largest base value to make caller terminate the loop */
60 return 16;
61 }
62
ossl_strtouint64(const variant_char * str)63 static uint64_t ossl_strtouint64(const variant_char *str)
64 {
65 uint64_t ret = 0;
66 unsigned int digit, base = 10;
67
68 if (*str == '0') {
69 base = 8, str++;
70 if (ossl_tolower(*str) == 'x')
71 base = 16, str++;
72 }
73
74 while ((digit = todigit(*str++)) < base)
75 ret = ret * base + digit;
76
77 return ret;
78 }
79
ossl_strchr(const variant_char * str,char srch)80 static variant_char *ossl_strchr(const variant_char *str, char srch)
81 { variant_char c;
82
83 while ((c = *str)) {
84 if (c == srch)
85 return (variant_char *)str;
86 str++;
87 }
88
89 return NULL;
90 }
91
92 # define OPENSSL_CPUID_SETUP
93 typedef uint64_t IA32CAP;
94
OPENSSL_cpuid_setup(void)95 void OPENSSL_cpuid_setup(void)
96 {
97 static int trigger = 0;
98 IA32CAP OPENSSL_ia32_cpuid(unsigned int *);
99 IA32CAP vec;
100 const variant_char *env;
101 int index = 2;
102
103 if (trigger)
104 return;
105
106 trigger = 1;
107 if ((env = ossl_getenv("OPENSSL_ia32cap")) != NULL) {
108 int off = (env[0] == '~') ? 1 : 0;
109
110 vec = ossl_strtouint64(env + off);
111
112 if (off) {
113 IA32CAP mask = vec;
114 vec = OPENSSL_ia32_cpuid(OPENSSL_ia32cap_P) & ~mask;
115 if (mask & (1<<24)) {
116 /*
117 * User disables FXSR bit, mask even other capabilities
118 * that operate exclusively on XMM, so we don't have to
119 * double-check all the time. We mask PCLMULQDQ, AMD XOP,
120 * AES-NI and AVX. Formally speaking we don't have to
121 * do it in x86_64 case, but we can safely assume that
122 * x86_64 users won't actually flip this flag.
123 */
124 vec &= ~((IA32CAP)(1<<1|1<<11|1<<25|1<<28) << 32);
125 }
126 } else if (env[0] == ':') {
127 vec = OPENSSL_ia32_cpuid(OPENSSL_ia32cap_P);
128 }
129
130 /* Processed indexes 0, 1 */
131 if ((env = ossl_strchr(env, ':')) != NULL)
132 env++;
133 for (; index < OPENSSL_IA32CAP_P_MAX_INDEXES; index += 2) {
134 if ((env != NULL) && (env[0] != '\0')) {
135 /* if env[0] == ':' current index is skipped */
136 if (env[0] != ':') {
137 IA32CAP vecx;
138
139 off = (env[0] == '~') ? 1 : 0;
140 vecx = ossl_strtouint64(env + off);
141 if (off) {
142 OPENSSL_ia32cap_P[index] &= ~(unsigned int)vecx;
143 OPENSSL_ia32cap_P[index + 1] &= ~(unsigned int)(vecx >> 32);
144 } else {
145 OPENSSL_ia32cap_P[index] = (unsigned int)vecx;
146 OPENSSL_ia32cap_P[index + 1] = (unsigned int)(vecx >> 32);
147 }
148 }
149 /* skip delimeter */
150 if ((env = ossl_strchr(env, ':')) != NULL)
151 env++;
152 } else { /* zeroize the next two indexes */
153 OPENSSL_ia32cap_P[index] = 0;
154 OPENSSL_ia32cap_P[index + 1] = 0;
155 }
156 }
157
158 /* If AVX10 is disabled, zero out its detailed cap bits */
159 if (!(OPENSSL_ia32cap_P[6] & (1 << 19)))
160 OPENSSL_ia32cap_P[9] = 0;
161 } else {
162 vec = OPENSSL_ia32_cpuid(OPENSSL_ia32cap_P);
163 }
164
165 /*
166 * |(1<<10) sets a reserved bit to signal that variable
167 * was initialized already... This is to avoid interference
168 * with cpuid snippets in ELF .init segment.
169 */
170 OPENSSL_ia32cap_P[0] = (unsigned int)vec | (1 << 10);
171 OPENSSL_ia32cap_P[1] = (unsigned int)(vec >> 32);
172 }
173 # else
174 unsigned int OPENSSL_ia32cap_P[OPENSSL_IA32CAP_P_MAX_INDEXES];
175 # endif
176 #endif
177
178 #ifndef OPENSSL_CPUID_OBJ
179 # ifndef OPENSSL_CPUID_SETUP
OPENSSL_cpuid_setup(void)180 void OPENSSL_cpuid_setup(void)
181 {
182 }
183 # endif
184
185 /*
186 * The rest are functions that are defined in the same assembler files as
187 * the CPUID functionality.
188 */
189
190 /*
191 * The volatile is used to ensure that the compiler generates code that reads
192 * all values from the array and doesn't try to optimize this away. The standard
193 * doesn't actually require this behavior if the original data pointed to is
194 * not volatile, but compilers do this in practice anyway.
195 *
196 * There are also assembler versions of this function.
197 */
198 # undef CRYPTO_memcmp
CRYPTO_memcmp(const void * in_a,const void * in_b,size_t len)199 int CRYPTO_memcmp(const void *in_a, const void *in_b, size_t len)
200 {
201 size_t i;
202 const volatile unsigned char *a = in_a;
203 const volatile unsigned char *b = in_b;
204 unsigned char x = 0;
205
206 for (i = 0; i < len; i++)
207 x |= a[i] ^ b[i];
208
209 return x;
210 }
211
212 /*
213 * For systems that don't provide an instruction counter register or equivalent.
214 */
OPENSSL_rdtsc(void)215 uint32_t OPENSSL_rdtsc(void)
216 {
217 return 0;
218 }
219
OPENSSL_instrument_bus(unsigned int * out,size_t cnt)220 size_t OPENSSL_instrument_bus(unsigned int *out, size_t cnt)
221 {
222 return 0;
223 }
224
OPENSSL_instrument_bus2(unsigned int * out,size_t cnt,size_t max)225 size_t OPENSSL_instrument_bus2(unsigned int *out, size_t cnt, size_t max)
226 {
227 return 0;
228 }
229 #endif
230