Make rand_pool buffers more dynamic in their sizing.

[thirdparty/openssl.git] / crypto / rand / rand_lcl.h

diff --git a/crypto/rand/rand_lcl.h b/crypto/rand/rand_lcl.h
index 1a77c89a5526bb2f1acb657c937bcdea60aebc02..e425d41090b048be7ce9662b63958b18f47451e6 100644 (file)
--- a/crypto/rand/rand_lcl.h
+++ b/crypto/rand/rand_lcl.h
@@ -82,6 +82,24 @@
  *                                1.5 * (RAND_DRBG_STRENGTH / 8))
  */
 
+/*
+ * Initial allocation minimum.
+ *
+ * There is a distinction between the secure and normal allocation minimums.
+ * Ideally, the secure allocation size should be a power of two.  The normal
+ * allocation size doesn't have any such restriction.
+ *
+ * The secure value is based on 128 bits of secure material, which is 16 bytes.
+ * Typically, the DRBGs will set a minimum larger than this so optimal
+ * allocation ought to take place (for full quality seed material).
+ *
+ * The normal value has been chosed by noticing that the rand_drbg_get_nonce
+ * function is usually the largest of the built in allocation (twenty four
+ * bytes and then appending another sixteen bytes).  This means the buffer ends
+ * with 40 bytes.  The value of forty eight is comfortably above this which
+ * allows some slack in the platform specific values used.
+ */
+# define RAND_POOL_MIN_ALLOCATION(secure) ((secure) ? 16 : 48)
 
 /* DRBG status values */
 typedef enum drbg_status_e {
@@ -184,6 +202,7 @@ struct rand_pool_st {
 
     size_t min_len; /* minimum number of random bytes requested */
     size_t max_len; /* maximum number of random bytes (allocated buffer size) */
+    size_t alloc_len; /* current number of bytes allocated */
     size_t entropy; /* current entropy count in bits */
     size_t entropy_requested; /* requested entropy count in bits */
 };