1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
|
/***************************************************************************
* _ _ ____ _
* Project ___| | | | _ \| |
* / __| | | | |_) | |
* | (__| |_| | _ <| |___
* \___|\___/|_| \_\_____|
*
* Copyright (C) 1998 - 2022, Daniel Stenberg, <daniel@haxx.se>, et al.
*
* This software is licensed as described in the file COPYING, which
* you should have received as part of this distribution. The terms
* are also available at https://curl.se/docs/copyright.html.
*
* You may opt to use, copy, modify, merge, publish, distribute and/or sell
* copies of the Software, and permit persons to whom the Software is
* furnished to do so, under the terms of the COPYING file.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
***************************************************************************/
#include "curl_setup.h"
#ifdef HAVE_FCNTL_H
#include <fcntl.h>
#endif
#include <curl/curl.h>
#include "vtls/vtls.h"
#include "sendf.h"
#include "rand.h"
/* The last 3 #include files should be in this order */
#include "curl_printf.h"
#include "curl_memory.h"
#include "memdebug.h"
static CURLcode randit(struct Curl_easy *data, unsigned int *rnd)
{
unsigned int r;
CURLcode result = CURLE_OK;
static unsigned int randseed;
static bool seeded = FALSE;
#ifdef CURLDEBUG
char *force_entropy = getenv("CURL_ENTROPY");
if(force_entropy) {
if(!seeded) {
unsigned int seed = 0;
size_t elen = strlen(force_entropy);
size_t clen = sizeof(seed);
size_t min = elen < clen ? elen : clen;
memcpy((char *)&seed, force_entropy, min);
randseed = ntohl(seed);
seeded = TRUE;
}
else
randseed++;
*rnd = randseed;
return CURLE_OK;
}
#endif
/* data may be NULL! */
result = Curl_ssl_random(data, (unsigned char *)rnd, sizeof(*rnd));
if(result != CURLE_NOT_BUILT_IN)
/* only if there is no random function in the TLS backend do the non crypto
version, otherwise return result */
return result;
/* ---- non-cryptographic version following ---- */
#ifdef RANDOM_FILE
if(!seeded) {
/* if there's a random file to read a seed from, use it */
int fd = open(RANDOM_FILE, O_RDONLY);
if(fd > -1) {
/* read random data into the randseed variable */
ssize_t nread = read(fd, &randseed, sizeof(randseed));
if(nread == sizeof(randseed))
seeded = TRUE;
close(fd);
}
}
#endif
if(!seeded) {
struct curltime now = Curl_now();
infof(data, "WARNING: using weak random seed");
randseed += (unsigned int)now.tv_usec + (unsigned int)now.tv_sec;
randseed = randseed * 1103515245 + 12345;
randseed = randseed * 1103515245 + 12345;
randseed = randseed * 1103515245 + 12345;
seeded = TRUE;
}
/* Return an unsigned 32-bit pseudo-random number. */
r = randseed = randseed * 1103515245 + 12345;
*rnd = (r << 16) | ((r >> 16) & 0xFFFF);
return CURLE_OK;
}
/*
* Curl_rand() stores 'num' number of random unsigned integers in the buffer
* 'rndptr' points to.
*
* If libcurl is built without TLS support or with a TLS backend that lacks a
* proper random API (Gskit or mbedTLS), this function will use "weak" random.
*
* When built *with* TLS support and a backend that offers strong random, it
* will return error if it cannot provide strong random values.
*
* NOTE: 'data' may be passed in as NULL when coming from external API without
* easy handle!
*
*/
CURLcode Curl_rand(struct Curl_easy *data, unsigned char *rnd, size_t num)
{
CURLcode result = CURLE_BAD_FUNCTION_ARGUMENT;
DEBUGASSERT(num > 0);
while(num) {
unsigned int r;
size_t left = num < sizeof(unsigned int) ? num : sizeof(unsigned int);
result = randit(data, &r);
if(result)
return result;
while(left) {
*rnd++ = (unsigned char)(r & 0xFF);
r >>= 8;
--num;
--left;
}
}
return result;
}
/*
* Curl_rand_hex() fills the 'rnd' buffer with a given 'num' size with random
* hexadecimal digits PLUS a zero terminating byte. It must be an odd number
* size.
*/
CURLcode Curl_rand_hex(struct Curl_easy *data, unsigned char *rnd,
size_t num)
{
CURLcode result = CURLE_BAD_FUNCTION_ARGUMENT;
const char *hex = "0123456789abcdef";
unsigned char buffer[128];
unsigned char *bufp = buffer;
DEBUGASSERT(num > 1);
#ifdef __clang_analyzer__
/* This silences a scan-build warning about accessing this buffer with
uninitialized memory. */
memset(buffer, 0, sizeof(buffer));
#endif
if((num/2 >= sizeof(buffer)) || !(num&1))
/* make sure it fits in the local buffer and that it is an odd number! */
return CURLE_BAD_FUNCTION_ARGUMENT;
num--; /* save one for zero termination */
result = Curl_rand(data, buffer, num/2);
if(result)
return result;
while(num) {
/* clang-tidy warns on this line without this comment: */
/* NOLINTNEXTLINE(clang-analyzer-core.UndefinedBinaryOperatorResult) */
*rnd++ = hex[(*bufp & 0xF0)>>4];
*rnd++ = hex[*bufp & 0x0F];
bufp++;
num -= 2;
}
*rnd = 0;
return result;
}
|
