git.distorted.org.uk Git - u/mdw/putty/blob - unix/uxnoise.c

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