X-Git-Url: https://git.distorted.org.uk/~mdw/catacomb/blobdiff_plain/3f078a9c1d674e911f8c4169930359d603ccd5fb..4199ce23fd3df23daccbf961b2ff1a2d42f89519:/rand/rand.c

diff --git a/rand/rand.c b/rand/rand.c
index 6787c11a..0d0650eb 100644
--- a/rand/rand.c
+++ b/rand/rand.c
@@ -161,24 +161,17 @@ CPU_DISPATCH(static, return, int, quick, (rand_pool *r), (r),
 
 static int trivial_quick(rand_pool *r) { return (-1); }
 
-#if __GNUC__ && (CPUFAM_X86 || CPUFAM_AMD64)
-static int rdrand_quick(rand_pool *r)
-{
-  unsigned long rr;
-  int i = 16;
-
-  __asm__ ("0: rdrand %0; jc 9f; dec %1; jnz 0b; 9:"
-	   : "=r" (rr), "=r" (i) : "1" (i) : "cc");
-  if (!i) return (-1);
-  rand_add(r, &rr, sizeof(rr), 8*sizeof(rr));
-  return (0);
-}
+#if CPUFAM_X86 || CPUFAM_AMD64
+extern int rand_quick_x86ish_rdrand(rand_pool */*r*/);
+extern int rand_quick_x86ish_rdseed(rand_pool */*r*/);
 #endif
 
 static quick__functype *pick_quick(void)
 {
-#if __GNUC__ && (CPUFAM_X86 || CPUFAM_AMD64)
-  DISPATCH_PICK_COND(rand_quick, rdrand_quick,
+#if CPUFAM_X86 || CPUFAM_AMD64
+  DISPATCH_PICK_COND(rand_quick, rand_quick_x86ish_rdseed,
+		     cpu_feature_p(CPUFEAT_X86_RDSEED));
+  DISPATCH_PICK_COND(rand_quick, rand_quick_x86ish_rdrand,
 		     cpu_feature_p(CPUFEAT_X86_RDRAND));
 #endif
   DISPATCH_PICK_FALLBACK(rand_quick, trivial_quick);
@@ -261,9 +254,7 @@ void rand_add(rand_pool *r, const void *p, size_t sz, unsigned goodbits)
   const octet *c = p;
   int i, rot;
 
-#if RAND_POOLSZ != 128
-#  error Polynomial in rand_add is out of date.  Fix it.
-#endif
+  STATIC_ASSERT(RAND_POOLSZ == 128, "Polynomial doesn't match pool size");
 
   RAND_RESOLVE(r);
 
@@ -316,6 +307,8 @@ void rand_gate(rand_pool *r)
   HASH_CTX hc;
   CIPHER_CTX cc;
 
+  STATIC_ASSERT(CIPHER_KEYSZ <= HASH_SZ, "rand cipher keysize too long");
+
   RAND_RESOLVE(r);
   QUICK(r);
 
@@ -331,7 +324,6 @@ void rand_gate(rand_pool *r)
 
   /* --- Now mangle all of the data based on the hash --- */
 
-  assert(CIPHER_KEYSZ <= HASH_SZ);
   CIPHER_INIT(&cc, h, CIPHER_KEYSZ, 0);
   CIPHER_ENCRYPT(&cc, r->pool, r->pool, RAND_POOLSZ);
   CIPHER_ENCRYPT(&cc, r->buf, r->buf, RAND_BUFSZ);
@@ -342,7 +334,7 @@ void rand_gate(rand_pool *r)
   r->o = RAND_SECSZ;
   r->obits += r->ibits;
   if (r->obits > RAND_OBITS) {
-    r->ibits = r->obits - r->ibits;
+    r->ibits = r->obits - RAND_OBITS;
     r->obits = RAND_OBITS;
   } else
     r->ibits = 0;
@@ -367,6 +359,8 @@ void rand_stretch(rand_pool *r)
   HASH_CTX hc;
   CIPHER_CTX cc;
 
+  STATIC_ASSERT(CIPHER_KEYSZ <= HASH_SZ, "rand cipher keysize too long");
+
   RAND_RESOLVE(r);
   QUICK(r);
 
@@ -382,7 +376,6 @@ void rand_stretch(rand_pool *r)
 
   /* --- Now mangle the buffer based on the hash --- */
 
-  assert(CIPHER_KEYSZ <= HASH_SZ);
   CIPHER_INIT(&cc, h, CIPHER_KEYSZ, 0);
   CIPHER_ENCRYPT(&cc, r->buf, r->buf, RAND_BUFSZ);
   BURN(cc);
@@ -420,7 +413,7 @@ void rand_get(rand_pool *r, void *p, size_t sz)
   if (!sz)
     return;
   for (;;) {
-    if (r->o + sz <= RAND_BUFSZ) {
+    if (sz <= RAND_BUFSZ - r->o) {
       memcpy(o, r->buf + r->o, sz);
       r->o += sz;
       break;
@@ -482,11 +475,15 @@ void rand_getgood(rand_pool *r, void *p, size_t sz)
 	chunk = r->obits / 8;
     }
 
-    if (chunk + r->o > RAND_BUFSZ)
+    if (chunk <= RAND_BUFSZ - r->o) {
+      memcpy(o, r->buf + r->o, chunk);
+      r->o += chunk;
+    } else {
       chunk = RAND_BUFSZ - r->o;
+      memcpy(o, r->buf + r->o, chunk);
+      rand_stretch(r);
+    }
 
-    memcpy(o, r->buf + r->o, chunk);
-    r->o += chunk;
     r->obits -= chunk * 8;
     o += chunk;
     sz -= chunk;