Line data Source code
1 : /* hwfeatures.c - Detect hardware features.
2 : * Copyright (C) 2007, 2011 Free Software Foundation, Inc.
3 : * Copyright (C) 2012 g10 Code GmbH
4 : *
5 : * This file is part of Libgcrypt.
6 : *
7 : * Libgcrypt is free software; you can redistribute it and/or modify
8 : * it under the terms of the GNU Lesser General Public License as
9 : * published by the Free Software Foundation; either version 2.1 of
10 : * the License, or (at your option) any later version.
11 : *
12 : * Libgcrypt is distributed in the hope that it will be useful,
13 : * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 : * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 : * GNU Lesser General Public License for more details.
16 : *
17 : * You should have received a copy of the GNU Lesser General Public
18 : * License along with this program; if not, see <http://www.gnu.org/licenses/>.
19 : */
20 :
21 : #include <config.h>
22 : #include <stdio.h>
23 : #include <ctype.h>
24 : #include <stdlib.h>
25 : #include <string.h>
26 : #include <stdarg.h>
27 : #include <unistd.h>
28 : #ifdef HAVE_SYSLOG
29 : # include <syslog.h>
30 : #endif /*HAVE_SYSLOG*/
31 :
32 : #include "g10lib.h"
33 : #include "hwf-common.h"
34 :
35 : /* The name of a file used to globally disable selected features. */
36 : #define HWF_DENY_FILE "/etc/gcrypt/hwf.deny"
37 :
38 : /* A table to map hardware features to a string. */
39 : static struct
40 : {
41 : unsigned int flag;
42 : const char *desc;
43 : } hwflist[] =
44 : {
45 : { HWF_PADLOCK_RNG, "padlock-rng" },
46 : { HWF_PADLOCK_AES, "padlock-aes" },
47 : { HWF_PADLOCK_SHA, "padlock-sha" },
48 : { HWF_PADLOCK_MMUL, "padlock-mmul"},
49 : { HWF_INTEL_CPU, "intel-cpu" },
50 : { HWF_INTEL_FAST_SHLD, "intel-fast-shld" },
51 : { HWF_INTEL_BMI2, "intel-bmi2" },
52 : { HWF_INTEL_SSSE3, "intel-ssse3" },
53 : { HWF_INTEL_PCLMUL, "intel-pclmul" },
54 : { HWF_INTEL_AESNI, "intel-aesni" },
55 : { HWF_INTEL_RDRAND, "intel-rdrand" },
56 : { HWF_INTEL_AVX, "intel-avx" },
57 : { HWF_INTEL_AVX2, "intel-avx2" },
58 : { HWF_ARM_NEON, "arm-neon" }
59 : };
60 :
61 : /* A bit vector with the hardware features which shall not be used.
62 : This variable must be set prior to any initialization. */
63 : static unsigned int disabled_hw_features;
64 :
65 : /* A bit vector describing the hardware features currently
66 : available. */
67 : static unsigned int hw_features;
68 :
69 : /* Convenience macros. */
70 : #define my_isascii(c) (!((c) & 0x80))
71 :
72 :
73 :
74 : /* Disable a feature by name. This function must be called *before*
75 : _gcry_detect_hw_features is called. */
76 : gpg_err_code_t
77 0 : _gcry_disable_hw_feature (const char *name)
78 : {
79 : int i;
80 :
81 0 : for (i=0; i < DIM (hwflist); i++)
82 0 : if (!strcmp (hwflist[i].desc, name))
83 : {
84 0 : disabled_hw_features |= hwflist[i].flag;
85 0 : return 0;
86 : }
87 0 : return GPG_ERR_INV_NAME;
88 : }
89 :
90 :
91 : /* Return a bit vector describing the available hardware features.
92 : The HWF_ constants are used to test for them. */
93 : unsigned int
94 105129 : _gcry_get_hw_features (void)
95 : {
96 105129 : return hw_features;
97 : }
98 :
99 :
100 : /* Enumerate all features. The caller is expected to start with an
101 : IDX of 0 and then increment IDX until NULL is returned. */
102 : const char *
103 15 : _gcry_enum_hw_features (int idx, unsigned int *r_feature)
104 : {
105 15 : if (idx < 0 || idx >= DIM (hwflist))
106 1 : return NULL;
107 14 : if (r_feature)
108 14 : *r_feature = hwflist[idx].flag;
109 14 : return hwflist[idx].desc;
110 : }
111 :
112 :
113 : /* Read a file with features which shall not be used. The file is a
114 : simple text file where empty lines and lines with the first non
115 : white-space character being '#' are ignored. */
116 : static void
117 31 : parse_hwf_deny_file (void)
118 : {
119 31 : const char *fname = HWF_DENY_FILE;
120 : FILE *fp;
121 : char buffer[256];
122 : char *p, *pend;
123 31 : int i, lnr = 0;
124 :
125 31 : fp = fopen (fname, "r");
126 31 : if (!fp)
127 31 : return;
128 :
129 : for (;;)
130 : {
131 0 : if (!fgets (buffer, sizeof buffer, fp))
132 : {
133 0 : if (!feof (fp))
134 : {
135 : #ifdef HAVE_SYSLOG
136 0 : syslog (LOG_USER|LOG_WARNING,
137 : "Libgcrypt warning: error reading '%s', line %d",
138 : fname, lnr);
139 : #endif /*HAVE_SYSLOG*/
140 : }
141 0 : fclose (fp);
142 0 : return;
143 : }
144 0 : lnr++;
145 0 : for (p=buffer; my_isascii (*p) && isspace (*p); p++)
146 : ;
147 0 : pend = strchr (p, '\n');
148 0 : if (pend)
149 0 : *pend = 0;
150 0 : pend = p + (*p? (strlen (p)-1):0);
151 0 : for ( ;pend > p; pend--)
152 0 : if (my_isascii (*pend) && isspace (*pend))
153 0 : *pend = 0;
154 0 : if (!*p || *p == '#')
155 0 : continue;
156 :
157 0 : for (i=0; i < DIM (hwflist); i++)
158 : {
159 0 : if (!strcmp (hwflist[i].desc, p))
160 : {
161 0 : disabled_hw_features |= hwflist[i].flag;
162 0 : break;
163 : }
164 : }
165 0 : if (i == DIM (hwflist))
166 : {
167 : #ifdef HAVE_SYSLOG
168 0 : syslog (LOG_USER|LOG_WARNING,
169 : "Libgcrypt warning: unknown feature in '%s', line %d",
170 : fname, lnr);
171 : #endif /*HAVE_SYSLOG*/
172 : }
173 0 : }
174 : }
175 :
176 :
177 : /* Detect the available hardware features. This function is called
178 : once right at startup and we assume that no other threads are
179 : running. */
180 : void
181 31 : _gcry_detect_hw_features (void)
182 : {
183 31 : hw_features = 0;
184 :
185 31 : if (fips_mode ())
186 31 : return; /* Hardware support is not to be evaluated. */
187 :
188 31 : parse_hwf_deny_file ();
189 :
190 : #if defined (HAVE_CPU_ARCH_X86)
191 : {
192 31 : hw_features = _gcry_hwf_detect_x86 ();
193 : }
194 : #endif /* HAVE_CPU_ARCH_X86 */
195 : #if defined (HAVE_CPU_ARCH_ARM)
196 : {
197 : hw_features = _gcry_hwf_detect_arm ();
198 : }
199 : #endif /* HAVE_CPU_ARCH_ARM */
200 :
201 31 : hw_features &= ~disabled_hw_features;
202 : }
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