1 /* Copyright (c) 2016, Google Inc.
2 *
3 * Permission to use, copy, modify, and/or distribute this software for any
4 * purpose with or without fee is hereby granted, provided that the above
5 * copyright notice and this permission notice appear in all copies.
6 *
7 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
8 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
9 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
10 * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
11 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
12 * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
13 * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
14
15 #include "internal.h"
16
17 #if defined(OPENSSL_ARM) && defined(OPENSSL_LINUX) && \
18 !defined(OPENSSL_STATIC_ARMCAP)
19 #include <errno.h>
20 #include <fcntl.h>
21 #include <sys/auxv.h>
22 #include <sys/types.h>
23 #include <unistd.h>
24
25 #include <openssl/arm_arch.h>
26 #include <openssl/mem.h>
27
28 #include "cpu_arm_linux.h"
29
open_eintr(const char * path,int flags)30 static int open_eintr(const char *path, int flags) {
31 int ret;
32 do {
33 ret = open(path, flags);
34 } while (ret < 0 && errno == EINTR);
35 return ret;
36 }
37
read_eintr(int fd,void * out,size_t len)38 static ssize_t read_eintr(int fd, void *out, size_t len) {
39 ssize_t ret;
40 do {
41 ret = read(fd, out, len);
42 } while (ret < 0 && errno == EINTR);
43 return ret;
44 }
45
46 // read_file opens |path| and reads until end-of-file. On success, it returns
47 // one and sets |*out_ptr| and |*out_len| to a newly-allocated buffer with the
48 // contents. Otherwise, it returns zero.
read_file(char ** out_ptr,size_t * out_len,const char * path)49 static int read_file(char **out_ptr, size_t *out_len, const char *path) {
50 int fd = open_eintr(path, O_RDONLY);
51 if (fd < 0) {
52 return 0;
53 }
54
55 static const size_t kReadSize = 1024;
56 int ret = 0;
57 size_t cap = kReadSize, len = 0;
58 char *buf = OPENSSL_malloc(cap);
59 if (buf == NULL) {
60 goto err;
61 }
62
63 for (;;) {
64 if (cap - len < kReadSize) {
65 size_t new_cap = cap * 2;
66 if (new_cap < cap) {
67 goto err;
68 }
69 char *new_buf = OPENSSL_realloc(buf, new_cap);
70 if (new_buf == NULL) {
71 goto err;
72 }
73 buf = new_buf;
74 cap = new_cap;
75 }
76
77 ssize_t bytes_read = read_eintr(fd, buf + len, kReadSize);
78 if (bytes_read < 0) {
79 goto err;
80 }
81 if (bytes_read == 0) {
82 break;
83 }
84 len += bytes_read;
85 }
86
87 *out_ptr = buf;
88 *out_len = len;
89 ret = 1;
90 buf = NULL;
91
92 err:
93 OPENSSL_free(buf);
94 close(fd);
95 return ret;
96 }
97
98 static int g_needs_hwcap2_workaround;
99
OPENSSL_cpuid_setup(void)100 void OPENSSL_cpuid_setup(void) {
101 // We ignore the return value of |read_file| and proceed with an empty
102 // /proc/cpuinfo on error. If |getauxval| works, we will still detect
103 // capabilities.
104 char *cpuinfo_data = NULL;
105 size_t cpuinfo_len = 0;
106 read_file(&cpuinfo_data, &cpuinfo_len, "/proc/cpuinfo");
107 STRING_PIECE cpuinfo;
108 cpuinfo.data = cpuinfo_data;
109 cpuinfo.len = cpuinfo_len;
110
111 // Matching OpenSSL, only report other features if NEON is present.
112 unsigned long hwcap = getauxval(AT_HWCAP);
113 if (hwcap & HWCAP_NEON) {
114 OPENSSL_armcap_P |= ARMV7_NEON;
115
116 // Some ARMv8 Android devices don't expose AT_HWCAP2. Fall back to
117 // /proc/cpuinfo. See https://crbug.com/boringssl/46. As of February 2021,
118 // this is now rare (see Chrome's Net.NeedsHWCAP2Workaround metric), but AES
119 // and PMULL extensions are very useful, so we still carry the workaround
120 // for now.
121 unsigned long hwcap2 = getauxval(AT_HWCAP2);
122 if (hwcap2 == 0) {
123 hwcap2 = crypto_get_arm_hwcap2_from_cpuinfo(&cpuinfo);
124 g_needs_hwcap2_workaround = hwcap2 != 0;
125 }
126
127 if (hwcap2 & HWCAP2_AES) {
128 OPENSSL_armcap_P |= ARMV8_AES;
129 }
130 if (hwcap2 & HWCAP2_PMULL) {
131 OPENSSL_armcap_P |= ARMV8_PMULL;
132 }
133 if (hwcap2 & HWCAP2_SHA1) {
134 OPENSSL_armcap_P |= ARMV8_SHA1;
135 }
136 if (hwcap2 & HWCAP2_SHA2) {
137 OPENSSL_armcap_P |= ARMV8_SHA256;
138 }
139 }
140
141 OPENSSL_free(cpuinfo_data);
142 }
143
CRYPTO_has_broken_NEON(void)144 int CRYPTO_has_broken_NEON(void) { return 0; }
145
CRYPTO_needs_hwcap2_workaround(void)146 int CRYPTO_needs_hwcap2_workaround(void) {
147 OPENSSL_init_cpuid();
148 return g_needs_hwcap2_workaround;
149 }
150
151 #endif // OPENSSL_ARM && OPENSSL_LINUX && !OPENSSL_STATIC_ARMCAP
152