| 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 | } |