svn commit: r349176 - head/sys/dev/random

[Conrad Meyer]

Author: cem
Date: Tue Jun 18 18:50:58 2019
New Revision: 349176
URL: https://svnweb.freebsd.org/changeset/base/349176

Log:
  random(4): Fix a regression in short AES mode reads
  
  In r349154, random device reads of size < 16 bytes (AES block size) were
  accidentally broken to loop forever.  Correct the loop condition for small
  reads.
  
  Reported by:	pho
  Reviewed by:	delphij
  Approved by:	secteam(delphij)
  Differential Revision:	https://reviews.freebsd.org/D20686

Modified:
  head/sys/dev/random/fortuna.c

Modified: head/sys/dev/random/fortuna.c
==============================================================================
--- head/sys/dev/random/fortuna.c	Tue Jun 18 17:51:30 2019	(r349175)
+++ head/sys/dev/random/fortuna.c	Tue Jun 18 18:50:58 2019	(r349176)
@@ -489,7 +489,7 @@ random_fortuna_genbytes(uint8_t *buf, size_t bytecount
 	if (!random_chachamode)
 		chunk_size = rounddown(chunk_size, RANDOM_BLOCKSIZE);
 
-	while (bytecount >= chunk_size) {
+	while (bytecount >= chunk_size && chunk_size > 0) {
 		randomdev_keystream(p_key, p_counter, buf, chunk_size);
 
 		buf += chunk_size;