Add flow control to platform rnd buf
Signed-off-by: Shelly Liberman <shelly.liberman@arm.com>
diff --git a/include/mbedtls/config.h b/include/mbedtls/config.h
index 43a9830..ee25107 100644
--- a/include/mbedtls/config.h
+++ b/include/mbedtls/config.h
@@ -2988,7 +2988,7 @@
*
* Uncomment to provide your own alternate implementation for mbedtls_platform_fault(),
* used in library/platform_util.c to signal a fault injection in either
- * mbedtls_platform_memcpy or mbedtls_platform_memset.
+ * mbedtls_platform_memcpy, mbedtls_platform_memset or mbedtls_platform_random_buf.
*
* You will need to provide a header "platform_fault.h" and an implementation at
* compile time.
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 )