1 /*
2 * Copyright (c) 2000-2002 by Solar Designer. See LICENSE.
3 */
4
5 #include <stdio.h>
6 #include <string.h>
7 #include <unistd.h>
8 #include <errno.h>
9 #include <fcntl.h>
10
11 #include "passwdqc.h"
12
13 #define SEPARATORS "_,.;:-!&"
14
read_loop(int fd,char * buffer,int count)15 static int read_loop(int fd, char *buffer, int count)
16 {
17 int offset, block;
18
19 offset = 0;
20 while (count > 0) {
21 block = read(fd, &buffer[offset], count);
22
23 if (block < 0) {
24 if (errno == EINTR) continue;
25 return block;
26 }
27 if (!block) return offset;
28
29 offset += block;
30 count -= block;
31 }
32
33 return offset;
34 }
35
_passwdqc_random(passwdqc_params_t * params)36 char *_passwdqc_random(passwdqc_params_t *params)
37 {
38 static char output[0x100];
39 int bits;
40 int use_separators, count, i;
41 unsigned int length;
42 char *start, *end;
43 int fd;
44 unsigned char bytes[2];
45
46 if (!(bits = params->random_bits))
47 return NULL;
48
49 count = 1 + ((bits - 12) + 14) / 15;
50 use_separators = ((bits + 11) / 12 != count);
51
52 length = count * 7 - 1;
53 if (length >= sizeof(output) || (int)length > params->max)
54 return NULL;
55
56 if ((fd = open("/dev/urandom", O_RDONLY)) < 0) return NULL;
57
58 length = 0;
59 do {
60 if (read_loop(fd, bytes, sizeof(bytes)) != sizeof(bytes)) {
61 close(fd);
62 return NULL;
63 }
64
65 i = (((int)bytes[1] & 0x0f) << 8) | (int)bytes[0];
66 start = _passwdqc_wordset_4k[i];
67 end = memchr(start, '\0', 6);
68 if (!end) end = start + 6;
69 if (length + (end - start) >= sizeof(output) - 1) {
70 close(fd);
71 return NULL;
72 }
73 memcpy(&output[length], start, end - start);
74 length += end - start;
75 bits -= 12;
76
77 if (use_separators && bits > 3) {
78 i = ((int)bytes[1] & 0x70) >> 4;
79 output[length++] = SEPARATORS[i];
80 bits -= 3;
81 } else
82 if (bits > 0)
83 output[length++] = ' ';
84 } while (bits > 0);
85
86 memset(bytes, 0, sizeof(bytes));
87 output[length] = '\0';
88
89 close(fd);
90
91 return output;
92 }
93