Wrapper functions added to generate non-zero random bytes

diff --git a/src/libstrongswan/crypto/rngs/rng.c b/src/libstrongswan/crypto/rngs/rng.c
index 67fd76910c57ebab740d3229afa8aecf60fd7dca..f8fd50d3f139cc91358260a78088ded33a6bec9b 100644 (file)
--- a/src/libstrongswan/crypto/rngs/rng.c
+++ b/src/libstrongswan/crypto/rngs/rng.c
@@ -1,4 +1,5 @@
 /*
+ * Copyright (C) 2012 Tobias Brunner
  * Copyright (C) 2008 Martin Willi
  * Hochschule fuer Technik Rapperswil
  *
@@ -20,3 +21,43 @@ ENUM(rng_quality_names, RNG_WEAK, RNG_TRUE,
        "RNG_STRONG",
        "RNG_TRUE",
 );
+
+/*
+ * Described in header.
+ */
+bool rng_get_bytes_not_zero(rng_t *rng, size_t len, u_int8_t *buffer, bool all)
+{
+       u_int8_t *pos = buffer, *check = buffer + (all ? len : min(1, len));
+
+       if (!rng->get_bytes(rng, len, pos))
+       {
+               return FALSE;
+       }
+
+       for (; pos < check; pos++)
+       {
+               while (*pos == 0)
+               {
+                       if (!rng->get_bytes(rng, 1, pos))
+                       {
+                               return FALSE;
+                       }
+               }
+       }
+       return TRUE;
+}
+
+/*
+ * Described in header.
+ */
+bool rng_allocate_bytes_not_zero(rng_t *rng, size_t len, chunk_t *chunk,
+                                                                bool all)
+{
+       *chunk = chunk_alloc(len);
+       if (!rng_get_bytes_not_zero(rng, len, chunk->ptr, all))
+       {
+               chunk_clear(chunk);
+               return FALSE;
+       }
+       return TRUE;
+}

diff --git a/src/libstrongswan/crypto/rngs/rng.h b/src/libstrongswan/crypto/rngs/rng.h
index 48ca52dd87722d17da9e646cbaba9fd21422f933..c72509b5459d0782f3084056d31cdcd97349bc5d 100644 (file)
--- a/src/libstrongswan/crypto/rngs/rng.h
+++ b/src/libstrongswan/crypto/rngs/rng.h
@@ -75,4 +75,31 @@ struct rng_t {
        void (*destroy) (rng_t *this);
 };
 
+/**
+ * Wrapper around rng_t.get_bytes() ensuring that either all bytes or at least
+ * the first byte is not zero.
+ *
+ * @param rng                  rng_t object
+ * @param len                  number of bytes to get
+ * @param buffer               pointer where the generated bytes will be written
+ * @param all                  TRUE if all bytes have to be non-zero
+ * @return                             TRUE if bytes successfully written
+ */
+bool rng_get_bytes_not_zero(rng_t *rng, size_t len, u_int8_t *buffer, bool all);
+
+/**
+ * Wrapper around rng_t.allocate_bytes() ensuring that either all bytes or at
+ * least the first byte is not zero.
+ *
+ * @param rng                  rng_t object
+ * @param len                  number of bytes to get
+ * @param buffer               pointer where the generated bytes will be written
+ * @param all                  TRUE if all bytes have to be non-zero
+ * @return                             TRUE if bytes successfully written
+ */
+bool rng_allocate_bytes_not_zero(rng_t *rng, size_t len, chunk_t *chunk,
+                                                                bool all);
+
+
+
 #endif /** RNG_H_ @}*/