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Commit | Line | Data |
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1c1af145 | 1 | /* |
2 | * Noise generation for PuTTY's cryptographic random number | |
3 | * generator. | |
4 | */ | |
5 | ||
6 | #include <stdio.h> | |
7 | #include <stdlib.h> | |
8 | #include <errno.h> | |
9 | ||
10 | #include <fcntl.h> | |
11 | #include <unistd.h> | |
12 | #include <sys/time.h> | |
13 | #include <sys/resource.h> | |
14 | ||
15 | #include "putty.h" | |
16 | #include "ssh.h" | |
17 | #include "storage.h" | |
18 | ||
19 | static int read_dev_urandom(char *buf, int len) | |
20 | { | |
21 | int fd; | |
22 | int ngot, ret; | |
23 | ||
24 | fd = open("/dev/urandom", O_RDONLY); | |
25 | if (fd < 0) | |
26 | return 0; | |
27 | ||
28 | ngot = 0; | |
29 | while (ngot < len) { | |
30 | ret = read(fd, buf+ngot, len-ngot); | |
31 | if (ret < 0) { | |
32 | close(fd); | |
33 | return 0; | |
34 | } | |
35 | ngot += ret; | |
36 | } | |
37 | ||
38 | close(fd); | |
39 | ||
40 | return 1; | |
41 | } | |
42 | ||
43 | /* | |
44 | * This function is called once, at PuTTY startup. It will do some | |
45 | * slightly silly things such as fetching an entire process listing | |
46 | * and scanning /tmp, load the saved random seed from disk, and | |
47 | * also read 32 bytes out of /dev/urandom. | |
48 | */ | |
49 | ||
50 | void noise_get_heavy(void (*func) (void *, int)) | |
51 | { | |
52 | char buf[512]; | |
53 | FILE *fp; | |
54 | int ret; | |
55 | int got_dev_urandom = 0; | |
56 | ||
57 | if (read_dev_urandom(buf, 32)) { | |
58 | got_dev_urandom = 1; | |
59 | func(buf, 32); | |
60 | } | |
61 | ||
62 | fp = popen("ps -axu 2>/dev/null", "r"); | |
63 | if (fp) { | |
64 | while ( (ret = fread(buf, 1, sizeof(buf), fp)) > 0) | |
65 | func(buf, ret); | |
66 | pclose(fp); | |
67 | } else if (!got_dev_urandom) { | |
68 | fprintf(stderr, "popen: %s\n" | |
69 | "Unable to access fallback entropy source\n", strerror(errno)); | |
70 | exit(1); | |
71 | } | |
72 | ||
73 | fp = popen("ls -al /tmp 2>/dev/null", "r"); | |
74 | if (fp) { | |
75 | while ( (ret = fread(buf, 1, sizeof(buf), fp)) > 0) | |
76 | func(buf, ret); | |
77 | pclose(fp); | |
78 | } else if (!got_dev_urandom) { | |
79 | fprintf(stderr, "popen: %s\n" | |
80 | "Unable to access fallback entropy source\n", strerror(errno)); | |
81 | exit(1); | |
82 | } | |
83 | ||
84 | read_random_seed(func); | |
85 | random_save_seed(); | |
86 | } | |
87 | ||
88 | void random_save_seed(void) | |
89 | { | |
90 | int len; | |
91 | void *data; | |
92 | ||
93 | if (random_active) { | |
94 | random_get_savedata(&data, &len); | |
95 | write_random_seed(data, len); | |
96 | sfree(data); | |
97 | } | |
98 | } | |
99 | ||
100 | /* | |
101 | * This function is called every time the random pool needs | |
102 | * stirring, and will acquire the system time. | |
103 | */ | |
104 | void noise_get_light(void (*func) (void *, int)) | |
105 | { | |
106 | struct timeval tv; | |
107 | gettimeofday(&tv, NULL); | |
108 | func(&tv, sizeof(tv)); | |
109 | } | |
110 | ||
111 | /* | |
112 | * This function is called on a timer, and grabs as much changeable | |
113 | * system data as it can quickly get its hands on. | |
114 | */ | |
115 | void noise_regular(void) | |
116 | { | |
117 | int fd; | |
118 | int ret; | |
119 | char buf[512]; | |
120 | struct rusage rusage; | |
121 | ||
122 | if ((fd = open("/proc/meminfo", O_RDONLY)) >= 0) { | |
123 | while ( (ret = read(fd, buf, sizeof(buf))) > 0) | |
124 | random_add_noise(buf, ret); | |
125 | close(fd); | |
126 | } | |
127 | if ((fd = open("/proc/stat", O_RDONLY)) >= 0) { | |
128 | while ( (ret = read(fd, buf, sizeof(buf))) > 0) | |
129 | random_add_noise(buf, ret); | |
130 | close(fd); | |
131 | } | |
132 | getrusage(RUSAGE_SELF, &rusage); | |
133 | random_add_noise(&rusage, sizeof(rusage)); | |
134 | } | |
135 | ||
136 | /* | |
137 | * This function is called on every keypress or mouse move, and | |
138 | * will add the current time to the noise pool. It gets the scan | |
139 | * code or mouse position passed in, and adds that too. | |
140 | */ | |
141 | void noise_ultralight(unsigned long data) | |
142 | { | |
143 | struct timeval tv; | |
144 | gettimeofday(&tv, NULL); | |
145 | random_add_noise(&tv, sizeof(tv)); | |
146 | random_add_noise(&data, sizeof(data)); | |
147 | } |