Switch from ossl_rand to DRBG rand

If RAND_add wraps around, XOR with existing. Add test to drbgtest that
does the wrap-around.

Re-order seeding and stop after first success.

Add RAND_poll_ex()

Use the DF and therefore lower RANDOMNESS_NEEDED.  Also, for child DRBG's,
mix in the address as the personalization bits.

Centralize the entropy callbacks, from drbg_lib to rand_lib.
(Conceptually, entropy is part of the enclosing application.)
Thanks to Dr. Matthias St Pierre for the suggestion.

Various code cleanups:
    -Make state an enum; inline RANDerr calls.
    -Add RAND_POLL_RETRIES (thanks Pauli for the idea)
    -Remove most RAND_seed calls from rest of library
    -Rename DRBG_CTX to RAND_DRBG, etc.
    -Move some code from drbg_lib to drbg_rand; drbg_lib is now only the
     implementation of NIST DRBG.
    -Remove blocklength

Reviewed-by: Paul Dale <paul.dale@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/4019)

1 files changed, 35 insertions, 29 deletions

diff --git a/include/internal/rand.h b/include/internal/rand.h
index 07568ea8b8..2f38095231 100644
--- a/include/internal/rand.h
+++ b/include/internal/rand.h
@@ -10,49 +10,55 @@
 #ifndef HEADER_DRBG_RAND_H
 # define HEADER_DRBG_RAND_H
 
-/* Flag for CTR mode only: use derivation function ctr_df */
+/* In CTR mode, use derivation function ctr_df */
 #define RAND_DRBG_FLAG_CTR_USE_DF            0x2
 
-const RAND_METHOD *RAND_drbg(void);
-
-int RAND_DRBG_set(DRBG_CTX *ctx, int type, unsigned int flags);
-DRBG_CTX *RAND_DRBG_new(int type, unsigned int flags, DRBG_CTX *parent);
-int RAND_DRBG_instantiate(DRBG_CTX *dctx,
+/*
+ * Object lifetime functions.
+ */
+RAND_DRBG *RAND_DRBG_new(int type, unsigned int flags, RAND_DRBG *parent);
+int RAND_DRBG_set(RAND_DRBG *drbg, int type, unsigned int flags);
+int RAND_DRBG_instantiate(RAND_DRBG *drbg,
                           const unsigned char *pers, size_t perslen);
-int RAND_DRBG_uninstantiate(DRBG_CTX *dctx);
-int RAND_DRBG_reseed(DRBG_CTX *dctx, const unsigned char *adin, size_t adinlen);
-int RAND_DRBG_generate(DRBG_CTX *dctx, unsigned char *out, size_t outlen,
+int RAND_DRBG_uninstantiate(RAND_DRBG *drbg);
+void RAND_DRBG_free(RAND_DRBG *drbg);
+
+/*
+ * Object "use" functions.
+ */
+int RAND_DRBG_reseed(RAND_DRBG *drbg,
+                     const unsigned char *adin, size_t adinlen);
+int RAND_DRBG_generate(RAND_DRBG *drbg, unsigned char *out, size_t outlen,
                        int prediction_resistance,
                        const unsigned char *adin, size_t adinlen);
-void RAND_DRBG_free(DRBG_CTX *dctx);
+int RAND_DRBG_set_reseed_interval(RAND_DRBG *drbg, int interval);
+
+/*
+ * EXDATA
+ */
+#define RAND_DRBG_get_ex_new_index(l, p, newf, dupf, freef) \
+    CRYPTO_get_ex_new_index(CRYPTO_EX_INDEX_DRBG, l, p, newf, dupf, freef)
+int RAND_DRBG_set_ex_data(RAND_DRBG *dctx, int idx, void *arg);
+void *RAND_DRBG_get_ex_data(const RAND_DRBG *dctx, int idx);
 
-typedef size_t (*RAND_DRBG_get_entropy_fn)(DRBG_CTX *ctx, unsigned char **pout,
+/*
+ * Callback functions.  See comments in drbg_lib.c
+ */
+typedef size_t (*RAND_DRBG_get_entropy_fn)(RAND_DRBG *ctx,
+                                           unsigned char **pout,
                                            int entropy, size_t min_len,
                                            size_t max_len);
-typedef void (*RAND_DRBG_cleanup_entropy_fn)(DRBG_CTX *ctx, unsigned char *out,
-                                             size_t olen);
-typedef size_t (*RAND_DRBG_get_nonce_fn)(DRBG_CTX *ctx, unsigned char **pout,
+typedef void (*RAND_DRBG_cleanup_entropy_fn)(RAND_DRBG *ctx,
+                                             unsigned char *out);
+typedef size_t (*RAND_DRBG_get_nonce_fn)(RAND_DRBG *ctx, unsigned char **pout,
                                          int entropy, size_t min_len,
                                          size_t max_len);
-typedef void (*RAND_DRBG_cleanup_nonce_fn)(DRBG_CTX *ctx, unsigned char *out,
-                                           size_t olen);
+typedef void (*RAND_DRBG_cleanup_nonce_fn)(RAND_DRBG *ctx, unsigned char *out);
 
-int RAND_DRBG_set_callbacks(DRBG_CTX *dctx,
+int RAND_DRBG_set_callbacks(RAND_DRBG *dctx,
                             RAND_DRBG_get_entropy_fn get_entropy,
                             RAND_DRBG_cleanup_entropy_fn cleanup_entropy,
                             RAND_DRBG_get_nonce_fn get_nonce,
                             RAND_DRBG_cleanup_nonce_fn cleanup_nonce);
 
-int RAND_DRBG_set_reseed_interval(DRBG_CTX *dctx, int interval);
-
-#define RAND_DRBG_get_ex_new_index(l, p, newf, dupf, freef) \
-    CRYPTO_get_ex_new_index(CRYPTO_EX_INDEX_DRBG, l, p, newf, dupf, freef)
-int RAND_DRBG_set_ex_data(DRBG_CTX *dctx, int idx, void *arg);
-void *RAND_DRBG_get_ex_data(const DRBG_CTX *dctx, int idx);
-
-DRBG_CTX *RAND_DRBG_get_default(void);
-
-
 #endif
-
-