base/dispatch.c, rand/rand.c, and asm: Support `rdseed' for quick noise.

[catacomb] / rand / rand.c

diff --git a/rand/rand.c b/rand/rand.c
index 6fcdf43..3b05633 100644 (file)
--- a/rand/rand.c
+++ b/rand/rand.c
@@ -27,6 +27,8 @@
 
 /*----- Header files ------------------------------------------------------*/
 
+#include "config.h"
+
 #include <stdarg.h>
 #include <stdio.h>
 #include <string.h>
@@ -35,6 +37,7 @@
 #include <mLib/sub.h>
 
 #include "arena.h"
+#include "dispatch.h"
 #include "paranoia.h"
 
 #define RAND__HACKS
@@ -68,7 +71,7 @@ typedef struct rand__gctx {
 
 gctx rand_global = {
   { &gops },
-  { { 0 }, 0, 0, 0,
+  { { 0 }, 0, 0, 0, 0,
     { 0 }, RAND_SECSZ, 0,
     { "Catacomb global random byte pool" },
     &noise_source }
@@ -79,9 +82,15 @@ gctx rand_global = {
 #define RAND_RESOLVE(r)                                                        \
   do { if ((r) == RAND_GLOBAL) r = &rand_global.p; } while (0)
 
-#define TIMER(r) do {                                                  \
-  if ((r)->s && (r)->s->timer)                                         \
-    (r)->s->timer(r);                                                  \
+#define GENCHECK(r) do {                                               \
+  unsigned gen = rand_generation();                                    \
+  if (r->gen != gen) { r->gen = gen; rand_gate(r); }                   \
+} while (0)
+
+static int quick(rand_pool *);
+#define QUICK(r) do {                                                  \
+  quick(r);                                                            \
+  if ((r)->s && (r)->s->timer) (r)->s->timer(r);                       \
 } while (0)
 
 /*----- Main code ---------------------------------------------------------*/
@@ -103,6 +112,7 @@ void rand_init(rand_pool *r)
   RAND_RESOLVE(r);
   memset(r->pool, 0, sizeof(r->pool));
   memset(r->buf, 0, sizeof(r->buf));
+  r->gen = rand_generation();
   r->i = 0;
   r->irot = 0;
   r->ibits = r->obits = 0;
@@ -135,6 +145,40 @@ void rand_noisesrc(rand_pool *r, const rand_source *s)
   r->s = s;
 }
 
+/* --- @rand_quick@ --- *
+ *
+ * Arguments:  @rand_pool *r@ = pointer to a randomness pool
+ *
+ * Returns:    Zero on success; @-1@ on failure.
+ *
+ * Use         Attempts to use some machine-specific `quick' source of
+ *             entropy to top up @r@.  This may not do anything at all on
+ *             many systems.
+ */
+
+CPU_DISPATCH(static, return, int, quick, (rand_pool *r), (r),
+            pick_quick, trivial_quick);
+
+static int trivial_quick(rand_pool *r) { return (-1); }
+
+#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 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);
+}
+
+int rand_quick(rand_pool *r) { RAND_RESOLVE(r); return (quick(r)); }
+
 /* --- @rand_seed@ --- *
  *
  * Arguments:  @rand_pool *r@ = pointer to a randomness pool
@@ -210,9 +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);
 
@@ -261,16 +303,20 @@ unsigned rand_goodbits(rand_pool *r)
 
 void rand_gate(rand_pool *r)
 {
-  octet h[HASH_SZ];
+  octet h[HASH_SZ], g[4];
   HASH_CTX hc;
   CIPHER_CTX cc;
 
+  STATIC_ASSERT(CIPHER_KEYSZ <= HASH_SZ, "rand cipher keysize too long");
+
   RAND_RESOLVE(r);
-  TIMER(r);
+  QUICK(r);
 
   /* --- Hash up all the data in the pool --- */
 
   HASH_INIT(&hc);
+  STORE32(g, r->gen); HASH(&hc, g, sizeof(g));
+  HASH(&hc, r->k.k, RAND_KEYSZ);
   HASH(&hc, r->pool, RAND_POOLSZ);
   HASH(&hc, r->buf, RAND_BUFSZ);
   HASH_DONE(&hc, h);
@@ -278,7 +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);
@@ -293,7 +338,7 @@ void rand_gate(rand_pool *r)
     r->obits = RAND_OBITS;
   } else
     r->ibits = 0;
-  TIMER(r);
+  QUICK(r);
 }
 
 /* --- @rand_stretch@ --- *
@@ -310,16 +355,20 @@ void rand_gate(rand_pool *r)
 
 void rand_stretch(rand_pool *r)
 {
-  octet h[HASH_SZ];
+  octet h[HASH_SZ], g[4];
   HASH_CTX hc;
   CIPHER_CTX cc;
 
+  STATIC_ASSERT(CIPHER_KEYSZ <= HASH_SZ, "rand cipher keysize too long");
+
   RAND_RESOLVE(r);
-  TIMER(r);
+  QUICK(r);
 
   /* --- Hash up all the data in the buffer --- */
 
   HASH_INIT(&hc);
+  STORE32(g, r->gen); HASH(&hc, g, sizeof(g));
+  HASH(&hc, r->k.k, RAND_KEYSZ);
   HASH(&hc, r->pool, RAND_POOLSZ);
   HASH(&hc, r->buf, RAND_BUFSZ);
   HASH_DONE(&hc, h);
@@ -327,7 +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);
@@ -335,7 +383,7 @@ void rand_stretch(rand_pool *r)
   /* --- Reset the various state variables --- */
 
   r->o = RAND_SECSZ;
-  TIMER(r);
+  QUICK(r);
 }
 
 /* --- @rand_get@ --- *
@@ -359,7 +407,8 @@ void rand_get(rand_pool *r, void *p, size_t sz)
   octet *o = p;
 
   RAND_RESOLVE(r);
-  TIMER(r);
+  GENCHECK(r);
+  QUICK(r);
 
   if (!sz)
     return;
@@ -412,7 +461,8 @@ void rand_getgood(rand_pool *r, void *p, size_t sz)
     rand_get(r, p, sz);
     return;
   }
-  TIMER(r);
+  GENCHECK(r);
+  QUICK(r);
 
   while (sz) {
     size_t chunk = sz;
@@ -514,7 +564,7 @@ static int gmisc(grand *r, unsigned op, ...)
       rand_seed(&g->p, va_arg(ap, unsigned));
       break;
     case RAND_TIMER:
-      TIMER(&g->p);
+      QUICK(&g->p);
       break;
     case RAND_GOODBITS:
       rc = rand_goodbits(&g->p);