X-Git-Url: https://git.distorted.org.uk/u/mdw/putty/blobdiff_plain/5d17ccfcfb6aaa0fe7b3fb1d90ffde20a1013cc1..6702cd9b0acb17017ae68581582cc6d9f158aef8:/sshrand.c

diff --git a/sshrand.c b/sshrand.c
index 43b81234..797fce73 100644
--- a/sshrand.c
+++ b/sshrand.c
@@ -4,6 +4,7 @@
 
 #include "putty.h"
 #include "ssh.h"
+#include <assert.h>
 
 /* Collect environmental noise every 5 minutes */
 #define NOISE_REGULAR_INTERVAL (5*60*TICKSPERSEC)
@@ -40,6 +41,8 @@ struct RandPool {
 
     unsigned char incomingb[HASHINPUT];
     int incomingpos;
+
+    int stir_pending;
 };
 
 static struct RandPool pool;
@@ -52,6 +55,14 @@ static void random_stir(void)
     word32 digest[HASHSIZE / sizeof(word32)];
     int i, j, k;
 
+    /*
+     * noise_get_light will call random_add_noise, which may call
+     * back to here. Prevent recursive stirs.
+     */
+    if (pool.stir_pending)
+	return;
+    pool.stir_pending = TRUE;
+
     noise_get_light(random_add_noise);
 
     SHATransform((word32 *) pool.incoming, (word32 *) pool.incomingb);
@@ -115,6 +126,8 @@ static void random_stir(void)
     memcpy(pool.incoming, digest, sizeof(digest));
 
     pool.poolpos = sizeof(pool.incoming);
+
+    pool.stir_pending = FALSE;
 }
 
 void random_add_noise(void *noise, int length)
@@ -186,9 +199,9 @@ static void random_add_heavynoise_bitbybit(void *noise, int length)
     pool.poolpos = i;
 }
 
-static void random_timer(void *ctx, long now)
+static void random_timer(void *ctx, unsigned long now)
 {
-    if (random_active > 0 && now - next_noise_collection >= 0) {
+    if (random_active > 0 && now == next_noise_collection) {
 	noise_regular();
 	next_noise_collection =
 	    schedule_timer(NOISE_REGULAR_INTERVAL, random_timer, &pool);
@@ -200,23 +213,30 @@ void random_ref(void)
     if (!random_active) {
 	memset(&pool, 0, sizeof(pool));    /* just to start with */
 
+        random_active++;
+
 	noise_get_heavy(random_add_heavynoise_bitbybit);
 	random_stir();
 
 	next_noise_collection =
 	    schedule_timer(NOISE_REGULAR_INTERVAL, random_timer, &pool);
     }
-
-    random_active++;
 }
 
 void random_unref(void)
 {
+    assert(random_active > 0);
+    if (random_active == 1) {
+        random_save_seed();
+        expire_timer_context(&pool);
+    }
     random_active--;
 }
 
 int random_byte(void)
 {
+    assert(random_active);
+
     if (pool.poolpos >= POOLSIZE)
 	random_stir();