The standards documents are silent on how to handle multi-part
output, so this is an RFC for something in the spirit of the
source specifications, but not actually required by them.

Signed-off-by: George Spelvin <li...@horizon.com>
---
 crypto/ansi_cprng.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/crypto/ansi_cprng.c b/crypto/ansi_cprng.c
index d39ce301..b88d3446 100644
--- a/crypto/ansi_cprng.c
+++ b/crypto/ansi_cprng.c
@@ -198,12 +198,14 @@ static int get_prng_bytes(u8 *buf, unsigned int nbytes,
 
        read_pos = ctx->rand_read_pos;
        if (byte_count > DEFAULT_BLK_SZ - read_pos) {
-               /* Leading partial block */
-               unsigned int avail = DEFAULT_BLK_SZ - read_pos;
+               if (ctx->flags & PRNG_DETERMINISTIC) {
+                       /* Return leftover data from previous call */
+                       unsigned int avail = DEFAULT_BLK_SZ - read_pos;
 
-               memcpy(ptr, ctx->rand_data.b + read_pos, avail);
-               ptr += avail;
-               byte_count -= avail;
+                       memcpy(ptr, ctx->rand_data.b + read_pos, avail);
+                       ptr += avail;
+                       byte_count -= avail;
+               }
                read_pos = 0;
 
                /* Intermediate full blocks */
-- 
2.1.3

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