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_SSE4_1, "intel-sse4.1" },
54 : { HWF_INTEL_PCLMUL, "intel-pclmul" },
55 : { HWF_INTEL_AESNI, "intel-aesni" },
56 : { HWF_INTEL_RDRAND, "intel-rdrand" },
57 : { HWF_INTEL_AVX, "intel-avx" },
58 : { HWF_INTEL_AVX2, "intel-avx2" },
59 : { HWF_ARM_NEON, "arm-neon" },
60 : { HWF_ARM_AES, "arm-aes" },
61 : { HWF_ARM_SHA1, "arm-sha1" },
62 : { HWF_ARM_SHA2, "arm-sha2" },
63 : { HWF_ARM_PMULL, "arm-pmull" }
64 : };
65 :
66 : /* A bit vector with the hardware features which shall not be used.
67 : This variable must be set prior to any initialization. */
68 : static unsigned int disabled_hw_features;
69 :
70 : /* A bit vector describing the hardware features currently
71 : available. */
72 : static unsigned int hw_features;
73 :
74 : /* Convenience macros. */
75 : #define my_isascii(c) (!((c) & 0x80))
76 :
77 :
78 :
79 : /* Disable a feature by name. This function must be called *before*
80 : _gcry_detect_hw_features is called. */
81 : gpg_err_code_t
82 0 : _gcry_disable_hw_feature (const char *name)
83 : {
84 : int i;
85 :
86 0 : if (!strcmp(name, "all"))
87 : {
88 0 : disabled_hw_features = ~0;
89 0 : return 0;
90 : }
91 :
92 0 : for (i=0; i < DIM (hwflist); i++)
93 0 : if (!strcmp (hwflist[i].desc, name))
94 : {
95 0 : disabled_hw_features |= hwflist[i].flag;
96 0 : return 0;
97 : }
98 0 : return GPG_ERR_INV_NAME;
99 : }
100 :
101 :
102 : /* Return a bit vector describing the available hardware features.
103 : The HWF_ constants are used to test for them. */
104 : unsigned int
105 0 : _gcry_get_hw_features (void)
106 : {
107 0 : return hw_features;
108 : }
109 :
110 :
111 : /* Enumerate all features. The caller is expected to start with an
112 : IDX of 0 and then increment IDX until NULL is returned. */
113 : const char *
114 0 : _gcry_enum_hw_features (int idx, unsigned int *r_feature)
115 : {
116 0 : if (idx < 0 || idx >= DIM (hwflist))
117 0 : return NULL;
118 0 : if (r_feature)
119 0 : *r_feature = hwflist[idx].flag;
120 0 : return hwflist[idx].desc;
121 : }
122 :
123 :
124 : /* Read a file with features which shall not be used. The file is a
125 : simple text file where empty lines and lines with the first non
126 : white-space character being '#' are ignored. */
127 : static void
128 0 : parse_hwf_deny_file (void)
129 : {
130 0 : const char *fname = HWF_DENY_FILE;
131 : FILE *fp;
132 : char buffer[256];
133 : char *p, *pend;
134 0 : int i, lnr = 0;
135 :
136 0 : fp = fopen (fname, "r");
137 0 : if (!fp)
138 0 : return;
139 :
140 : for (;;)
141 : {
142 0 : if (!fgets (buffer, sizeof buffer, fp))
143 : {
144 0 : if (!feof (fp))
145 : {
146 : #ifdef HAVE_SYSLOG
147 0 : syslog (LOG_USER|LOG_WARNING,
148 : "Libgcrypt warning: error reading '%s', line %d",
149 : fname, lnr);
150 : #endif /*HAVE_SYSLOG*/
151 : }
152 0 : fclose (fp);
153 0 : return;
154 : }
155 0 : lnr++;
156 0 : for (p=buffer; my_isascii (*p) && isspace (*p); p++)
157 : ;
158 0 : pend = strchr (p, '\n');
159 0 : if (pend)
160 0 : *pend = 0;
161 0 : pend = p + (*p? (strlen (p)-1):0);
162 0 : for ( ;pend > p; pend--)
163 0 : if (my_isascii (*pend) && isspace (*pend))
164 0 : *pend = 0;
165 0 : if (!*p || *p == '#')
166 0 : continue;
167 :
168 0 : if (_gcry_disable_hw_feature (p) == GPG_ERR_INV_NAME)
169 : {
170 : #ifdef HAVE_SYSLOG
171 0 : syslog (LOG_USER|LOG_WARNING,
172 : "Libgcrypt warning: unknown feature in '%s', line %d",
173 : fname, lnr);
174 : #endif /*HAVE_SYSLOG*/
175 : }
176 : }
177 : }
178 :
179 :
180 : /* Detect the available hardware features. This function is called
181 : once right at startup and we assume that no other threads are
182 : running. */
183 : void
184 0 : _gcry_detect_hw_features (void)
185 : {
186 0 : hw_features = 0;
187 :
188 0 : if (fips_mode ())
189 0 : return; /* Hardware support is not to be evaluated. */
190 :
191 0 : parse_hwf_deny_file ();
192 :
193 : #if defined (HAVE_CPU_ARCH_X86)
194 : {
195 0 : hw_features = _gcry_hwf_detect_x86 ();
196 : }
197 : #endif /* HAVE_CPU_ARCH_X86 */
198 : #if defined (HAVE_CPU_ARCH_ARM)
199 : {
200 : hw_features = _gcry_hwf_detect_arm ();
201 : }
202 : #endif /* HAVE_CPU_ARCH_ARM */
203 :
204 0 : hw_features &= ~disabled_hw_features;
205 : }
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