rand: trust user supplied entropy when configured without a random source

Fixes #20841

Reviewed-by: Tomas Mraz <tomas@openssl.org>
Reviewed-by: Matthias St. Pierre <Matthias.St.Pierre@ncp-e.com>
(Merged from https://github.com/openssl/openssl/pull/20843)

diff --git a/crypto/rand/rand_lib.c b/crypto/rand/rand_lib.c
index ce95bf6210b15dc8bb951f6cdf3ba5f09c10d1c5..0cdb9caa6ddc56e2dc950c675a6205a3e63830df 100644 (file)
--- a/crypto/rand/rand_lib.c
+++ b/crypto/rand/rand_lib.c
@@ -273,7 +273,13 @@ void RAND_add(const void *buf, int num, double randomness)
 # endif
     drbg = RAND_get0_primary(NULL);
     if (drbg != NULL && num > 0)
+# ifdef OPENSSL_RAND_SEED_NONE
+        /* Without an entropy source, we have to rely on the user */
+        EVP_RAND_reseed(drbg, 0, buf, num, NULL, 0);
+# else
+        /* With an entropy source, we downgrade this to additional input */
         EVP_RAND_reseed(drbg, 0, NULL, 0, buf, num);
+# endif
 }
 
 # if !defined(OPENSSL_NO_DEPRECATED_1_1_0)