Make crypto_pseudo_rand* never fail.

svn:r797

2 files changed, 17 insertions, 5 deletions

diff --git a/src/common/crypto.c b/src/common/crypto.c
index 8da2916dc..afec91d22 100644
--- a/src/common/crypto.c
+++ b/src/common/crypto.c
@@ -999,10 +999,23 @@ int crypto_rand(unsigned int n, unsigned char *to)
   return (RAND_bytes(to, n) != 1);
 }
 
-int crypto_pseudo_rand(unsigned int n, unsigned char *to)
+void crypto_pseudo_rand(unsigned int n, unsigned char *to)
 {
   assert(to);
-  return (RAND_pseudo_bytes(to, n) == -1);
+  if (RAND_pseudo_bytes(to, n) == -1) {
+    log_fn(LOG_ERR, "RAND_pseudo_bytes failed unexpectedly.");
+    exit(1);
+  }
+}
+
+int crypto_pseudo_rand_int(int max) {
+  unsigned int val;
+  crypto_pseudo_rand(sizeof(val), (unsigned char*) &val);
+  /* Bug: Low values are _slightly_ favored over high values because
+   * ((unsigned)-1)%max != max-1 .  This shouldn't matter if max is
+   * significantly smaller than ((unsigned)-1).
+   **/
+  return val % max;
 }
 
 /* errors */
diff --git a/src/common/crypto.h b/src/common/crypto.h
index 31e995d3b..ab5422d8c 100644
--- a/src/common/crypto.h
+++ b/src/common/crypto.h
@@ -100,9 +100,8 @@ int crypto_SHA_digest(unsigned char *m, int len, unsigned char *digest);
 /* random numbers */
 int crypto_seed_rng();
 int crypto_rand(unsigned int n, unsigned char *to);
-int crypto_pseudo_rand(unsigned int n, unsigned char *to);
-
-#define CRYPTO_PSEUDO_RAND_INT(v) crypto_pseudo_rand(sizeof(v),(char*)&(v))
+void crypto_pseudo_rand(unsigned int n, unsigned char *to);
+int crypto_pseudo_rand_int(int max);
 
 /* errors */
 char *crypto_perror();