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/*
* Noise generation for PuTTY's cryptographic random number
* generator.
*/
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/time.h>
#include <sys/resource.h>
#include "putty.h"
#include "ssh.h"
#include "storage.h"
static bool read_dev_urandom(char *buf, int len)
{
int fd;
int ngot, ret;
fd = open("/dev/urandom", O_RDONLY);
if (fd < 0)
return false;
ngot = 0;
while (ngot < len) {
ret = read(fd, buf+ngot, len-ngot);
if (ret < 0) {
close(fd);
return false;
}
ngot += ret;
}
close(fd);
return true;
}
/*
* This function is called once, at PuTTY startup. It will do some
* slightly silly things such as fetching an entire process listing
* and scanning /tmp, load the saved random seed from disk, and
* also read 32 bytes out of /dev/urandom.
*/
void noise_get_heavy(void (*func) (void *, int))
{
char buf[512];
FILE *fp;
int ret;
bool got_dev_urandom = false;
if (read_dev_urandom(buf, 32)) {
got_dev_urandom = true;
func(buf, 32);
}
fp = popen("ps -axu 2>/dev/null", "r");
if (fp) {
while ( (ret = fread(buf, 1, sizeof(buf), fp)) > 0)
func(buf, ret);
pclose(fp);
} else if (!got_dev_urandom) {
fprintf(stderr, "popen: %s\n"
"Unable to access fallback entropy source\n", strerror(errno));
exit(1);
}
fp = popen("ls -al /tmp 2>/dev/null", "r");
if (fp) {
while ( (ret = fread(buf, 1, sizeof(buf), fp)) > 0)
func(buf, ret);
pclose(fp);
} else if (!got_dev_urandom) {
fprintf(stderr, "popen: %s\n"
"Unable to access fallback entropy source\n", strerror(errno));
exit(1);
}
read_random_seed(func);
}
/*
* This function is called on a timer, and grabs as much changeable
* system data as it can quickly get its hands on.
*/
void noise_regular(void)
{
int fd;
int ret;
char buf[512];
struct rusage rusage;
if ((fd = open("/proc/meminfo", O_RDONLY)) >= 0) {
while ( (ret = read(fd, buf, sizeof(buf))) > 0)
random_add_noise(NOISE_SOURCE_MEMINFO, buf, ret);
close(fd);
}
if ((fd = open("/proc/stat", O_RDONLY)) >= 0) {
while ( (ret = read(fd, buf, sizeof(buf))) > 0)
random_add_noise(NOISE_SOURCE_STAT, buf, ret);
close(fd);
}
getrusage(RUSAGE_SELF, &rusage);
random_add_noise(NOISE_SOURCE_RUSAGE, &rusage, sizeof(rusage));
}
/*
* This function is called on every keypress or mouse move, and
* will add the current time to the noise pool. It gets the scan
* code or mouse position passed in, and adds that too.
*/
void noise_ultralight(NoiseSourceId id, unsigned long data)
{
struct timeval tv;
gettimeofday(&tv, NULL);
random_add_noise(NOISE_SOURCE_TIME, &tv, sizeof(tv));
random_add_noise(id, &data, sizeof(data));
}
uint64_t prng_reseed_time_ms(void)
{
struct timeval tv;
gettimeofday(&tv, NULL);
return tv.tv_sec * 1000 + tv.tv_usec / 1000;
}
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