First attempt at a Unix port of Plink. Seems to basically work;

[u/mdw/putty] / unix / uxnoise.c

diff --git a/unix/uxnoise.c b/unix/uxnoise.c
new file mode 100644 (file)
index 0000000..91f9c2b
--- /dev/null
+++ b/unix/uxnoise.c
@@ -0,0 +1,95 @@
+/*
+ * Noise generation for PuTTY's cryptographic random number
+ * generator.
+ */
+
+#include <stdio.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/time.h>
+
+#include "putty.h"
+#include "ssh.h"
+#include "storage.h"
+
+/*
+ * FIXME. This module currently depends critically on /dev/urandom,
+ * because it has no fallback mechanism for doing anything else.
+ */
+
+static void read_dev_urandom(char *buf, int len)
+{
+    int fd;
+    int ngot, ret;
+
+    fd = open("/dev/urandom", O_RDONLY);
+    if (fd < 0) {
+       perror("/dev/urandom: open");
+       exit(1);
+    }
+
+    ngot = 0;
+    while (ngot < len) {
+       ret = read(fd, buf+ngot, len-ngot);
+       if (ret < 0) {
+           perror("/dev/urandom: read");
+           exit(1);
+       }
+       ngot += ret;
+    }
+}
+
+/*
+ * This function is called once, at PuTTY startup. Currently it
+ * will read 32 bytes out of /dev/urandom and seed the internal
+ * generator with them.
+ */
+
+void noise_get_heavy(void (*func) (void *, int))
+{
+    char buf[32];
+    read_dev_urandom(buf, sizeof(buf));
+    func(buf, sizeof(buf));
+}
+
+void random_save_seed(void)
+{
+    /* Currently we do nothing here. FIXME? */
+}
+
+/*
+ * This function is called every time the urandom pool needs
+ * stirring, and will acquire the system time.
+ */
+void noise_get_light(void (*func) (void *, int))
+{
+    struct timeval tv;
+    gettimeofday(&tv, NULL);
+    func(&tv, sizeof(tv));
+}
+
+/*
+ * This function is called on a timer, and it will just pull some
+ * stuff out of /dev/urandom. FIXME: really I suspect we ought not
+ * to deplete /dev/urandom like this. Better to grab something more
+ * harmless.
+ */
+void noise_regular(void)
+{
+    char buf[4];
+    read_dev_urandom(buf, sizeof(buf));
+    random_add_noise(buf, sizeof(buf));
+}
+
+/*
+ * 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(unsigned long data)
+{
+    struct timeval tv;
+    gettimeofday(&tv, NULL);
+    random_add_noise(&tv, sizeof(tv));
+    random_add_noise(&data, sizeof(data));
+}