commit 7326c62efbac67775740a29e6a394013638a2970
author Shelly Liberman <shelly.liberman@arm.com> Tue Dec 01 13:28:30 2020 +0200
committer Shelly Liberman <shelly.liberman@arm.com> Tue Dec 01 14:04:51 2020 +0200
tree 99548a12781b51bb2b47a974420f1c3dcf52470a
parent 26bea336749b49a41782a32a0ed077c3419bccf8

Add flow control to platform rnd buf

Signed-off-by: Shelly Liberman <shelly.liberman@arm.com>

library/platform_util.c

diff --git a/library/platform_util.c b/library/platform_util.c
index ecfdb84..c808750 100644
--- a/library/platform_util.c
+++ b/library/platform_util.c
@@ -334,6 +334,7 @@
 
 void mbedtls_platform_random_buf( uint8_t *buf, size_t len )
 {
+    volatile size_t flow_control = 0;
     uint16_t val;
 
     while( len > 1 )
@@ -342,13 +343,19 @@
         buf[len-1] = (uint8_t)val;
         buf[len-2] = (uint8_t)(val>>8);
         len -= 2;
+        flow_control += 2;
     }
     if( len == 1 )
     {
         buf[0] = (uint8_t)mbedtls_platform_random_uint16();
+        flow_control ++;
     }
 
-    return;
+    if ( flow_control == len )
+    {
+        return;
+    }
+    mbedtls_platform_fault();
 }
 
 uint32_t mbedtls_platform_random_in_range( uint32_t num )