Simplifications in the RNG code.

diff --git a/lib/nettle/rnd-common.c b/lib/nettle/rnd-common.c
index 24737433ed3a0202f1e732c038563e38511148fa..ea89797669d3578f76361b6c6ef8119478d3f23a 100644 (file)
--- a/lib/nettle/rnd-common.c
+++ b/lib/nettle/rnd-common.c
@@ -40,6 +40,14 @@
 /* gnulib wants to claim strerror even if it cannot provide it. WTF */
 #undef strerror
 
+#ifdef HAVE_GETRUSAGE
+# ifdef RUSAGE_THREAD
+#  define ARG_RUSAGE RUSAGE_THREAD
+# else
+#  define ARG_RUSAGE RUSAGE_SELF
+# endif
+#endif
+
 void _rnd_get_event(struct event_st *e)
 {
        static unsigned count = 0;
@@ -47,11 +55,7 @@ void _rnd_get_event(struct event_st *e)
        gettime(&e->now);
 
 #ifdef HAVE_GETRUSAGE
-#ifdef RUSAGE_THREAD
-       if (getrusage(RUSAGE_THREAD, &e->rusage) < 0) {
-#else
-       if (getrusage(RUSAGE_SELF, &e->rusage) < 0) {
-#endif
+       if (getrusage(ARG_RUSAGE, &e->rusage) < 0) {
                _gnutls_debug_log("getrusage failed: %s\n",
                                  strerror(errno));
                abort();
@@ -68,6 +72,8 @@ void _rnd_get_event(struct event_st *e)
 }
 
 #ifdef _WIN32
+/* The windows randomness gatherer.
+ */
 
 #include <windows.h>
 #include <wincrypt.h>
@@ -109,6 +115,9 @@ void _rnd_system_entropy_deinit(void)
 
 #else /* POSIX */
 
+/* The POSIX (Linux-BSD) randomness gatherer.
+ */
+
 #include <time.h>
 #include <sys/types.h>
 #include <sys/stat.h>

diff --git a/lib/nettle/rnd.c b/lib/nettle/rnd.c
index fd75eb4d9aeb4348587506e8827e2dd872d24a78..18bcbf32aac7e18647a7c79e741a780025da3716 100644 (file)
--- a/lib/nettle/rnd.c
+++ b/lib/nettle/rnd.c
@@ -73,7 +73,7 @@ struct rnd_ctx_st {
 
 static struct rnd_ctx_st rnd_ctx;
 
-/* after this number of bytes salsa20 will reseed */
+/* after this number of bytes salsa20 will rekey */
 #define NONCE_RESEED_BYTES (1048576)
 static struct nonce_ctx_st nonce_ctx;
 
@@ -168,30 +168,34 @@ static void wrap_nettle_rnd_deinit(void *ctx)
        rnd_ctx.mutex = NULL;
 }
 
-static int nonce_rng_init(struct nonce_ctx_st *ctx, struct event_st *event, unsigned init)
+static int nonce_rng_init(struct nonce_ctx_st *ctx, unsigned init)
 {
        uint8_t buffer[SALSA20_KEY_SIZE];
+       uint8_t iv[8];
        int ret;
 
-       /* Get a key from the standard RNG or from the entropy source.  */
+       /* Get a key from the system randomness source.  */
        ret = _rnd_get_system_entropy(buffer, sizeof(buffer));
        if (ret < 0)
                return gnutls_assert_val(ret);
 
        if (init == 0) {
-               /* Add continuity by XORing the new key with data generated
+               /* use the previous key to generate IV as well */
+               memset(iv, 0, sizeof(iv)); /* to prevent valgrind from whinning */
+               salsa20r12_crypt(&ctx->ctx, sizeof(iv), iv, iv);
+
+               /* Add key continuity by XORing the new key with data generated
                 * from the old key */
                salsa20r12_crypt(&ctx->ctx, sizeof(buffer), buffer, buffer);
+       } else {
+               /* when initializing read the IV from the system randomness source */
+               ret = _rnd_get_system_entropy(iv, sizeof(iv));
+               if (ret < 0)
+                       return gnutls_assert_val(ret);
        }
 
        salsa20_set_key(&ctx->ctx, sizeof(buffer), buffer);
-
-       if (sizeof(struct event_st) < 8) {
-               abort();
-       }
-
-       if (event != NULL)
-               salsa20_set_iv(&ctx->ctx, (void*)event);
+       salsa20_set_iv(&ctx->ctx, iv);
 
        zeroize_key(buffer, sizeof(buffer));
 
@@ -250,7 +254,7 @@ static int wrap_nettle_rnd_init(void **ctx)
        yarrow256_slow_reseed(&rnd_ctx.yctx);
 
        /* initialize the nonce RNG */
-       ret = nonce_rng_init(&nonce_ctx, &event, 1);
+       ret = nonce_rng_init(&nonce_ctx, 1);
        if (ret < 0)
                return gnutls_assert_val(ret);
 
@@ -279,7 +283,7 @@ wrap_nettle_rnd_nonce(void *_ctx, void *data, size_t datasize)
 
        if (reseed != 0 || nonce_ctx.counter > NONCE_RESEED_BYTES) {
                /* reseed nonce */
-               ret = nonce_rng_init(&nonce_ctx, NULL, 0);
+               ret = nonce_rng_init(&nonce_ctx, 0);
                if (ret < 0) {
                        gnutls_assert();
                        goto cleanup;
@@ -355,7 +359,7 @@ static void wrap_nettle_rnd_refresh(void *_ctx)
        RND_UNLOCK(&rnd_ctx);
 
        RND_LOCK(&nonce_ctx);
-       nonce_rng_init(&nonce_ctx, &event, 0);
+       nonce_rng_init(&nonce_ctx, 0);
        RND_UNLOCK(&nonce_ctx);
 
        return;