X-Git-Url: https://git.distorted.org.uk/u/mdw/putty/blobdiff_plain/374330e25a6b51c40436fa869a381dd510790f6e..38c4a8da5955bf0572be423ce46866285b7bcf59:/sshrand.c

diff --git a/sshrand.c b/sshrand.c
index 17ef6e34..21a1b833 100644
--- a/sshrand.c
+++ b/sshrand.c
@@ -39,22 +39,7 @@ struct RandPool {
 };
 
 static struct RandPool pool;
-
-void random_add_noise(void *noise, int length) {
-    unsigned char *p = noise;
-
-    while (length >= (HASHINPUT - pool.incomingpos)) {
-	memcpy(pool.incomingb + pool.incomingpos, p,
-	       HASHINPUT - pool.incomingpos);
-	p += HASHINPUT - pool.incomingpos;
-	length -= HASHINPUT - pool.incomingpos;
-	SHATransform((word32 *)pool.incoming, (word32 *)pool.incomingb);
-	pool.incomingpos = 0;
-    }
-
-    memcpy(pool.incomingb, p, length);
-    pool.incomingpos = length;
-}
+static int random_active = 0;
 
 void random_stir(void) {
     word32 block[HASHINPUT/sizeof(word32)];
@@ -121,37 +106,83 @@ void random_stir(void) {
      * there'll be some extra bizarreness there.
      */
     SHATransform(digest, block);
-    memcpy(digest, pool.incoming, sizeof(digest));
+    memcpy(pool.incoming, digest, sizeof(digest));
 
     pool.poolpos = sizeof(pool.incoming);
 }
 
-static void random_add_heavynoise(void *noise, int length) {
+void random_add_noise(void *noise, int length) {
     unsigned char *p = noise;
+    int i;
 
-    while (length >= (POOLSIZE - pool.poolpos)) {
-	memcpy(pool.pool + pool.poolpos, p, POOLSIZE - pool.poolpos);
-	p += POOLSIZE - pool.poolpos;
-	length -= POOLSIZE - pool.poolpos;
+    if (!random_active)
+        return;
+
+    /*
+     * This function processes HASHINPUT bytes into only HASHSIZE
+     * bytes, so _if_ we were getting incredibly high entropy
+     * sources then we would be throwing away valuable stuff.
+     */
+    while (length >= (HASHINPUT - pool.incomingpos)) {
+	memcpy(pool.incomingb + pool.incomingpos, p,
+	       HASHINPUT - pool.incomingpos);
+	p += HASHINPUT - pool.incomingpos;
+	length -= HASHINPUT - pool.incomingpos;
+	SHATransform((word32 *)pool.incoming, (word32 *)pool.incomingb);
+        for (i = 0; i < HASHSIZE; i++) {
+            pool.pool[pool.poolpos++] ^= pool.incomingb[i];
+            if (pool.poolpos >= POOLSIZE)
+                pool.poolpos = 0;
+        }
+        if (pool.poolpos < HASHSIZE)
+            random_stir();
+
+	pool.incomingpos = 0;
+    }
+
+    memcpy(pool.incomingb + pool.incomingpos, p, length);
+    pool.incomingpos += length;
+}
+
+void random_add_heavynoise(void *noise, int length) {
+    unsigned char *p = noise;
+    int i;
+
+    while (length >= POOLSIZE) {
+        for (i = 0; i < POOLSIZE; i++)
+            pool.pool[i] ^= *p++;
 	random_stir();
-	pool.poolpos = 0;
+	length -= POOLSIZE;
     }
 
-    memcpy(pool.pool, p, length);
-    pool.poolpos = length;
+    for (i = 0; i < length; i++)
+        pool.pool[i] ^= *p++;
+    random_stir();
+}
+
+static void random_add_heavynoise_bitbybit(void *noise, int length) {
+    unsigned char *p = noise;
+    int i;
+
+    while (length >= POOLSIZE - pool.poolpos) {
+        for (i = 0; i < POOLSIZE - pool.poolpos; i++)
+            pool.pool[pool.poolpos + i] ^= *p++;
+	random_stir();
+	length -= POOLSIZE - pool.poolpos;
+        pool.poolpos = 0;
+    }
+
+    for (i = 0; i < length; i++)
+        pool.pool[i] ^= *p++;
+    pool.poolpos = i;
 }
 
 void random_init(void) {
     memset(&pool, 0, sizeof(pool));    /* just to start with */
 
-    /*
-     * For noise_get_heavy, we temporarily use `poolpos' as the
-     * pointer for addition of noise, rather than extraction of
-     * random numbers.
-     */
-    pool.poolpos = 0;
-    noise_get_heavy(random_add_heavynoise);
+    random_active = 1;
 
+    noise_get_heavy(random_add_heavynoise_bitbybit);
     random_stir();
 }