commit e91f0dc905dde1177140de4452601883dca84d63
author Arto Kinnunen <arto.kinnunen@arm.com> Mon Dec 30 17:32:58 2019 +0200
committer Arto Kinnunen <arto.kinnunen@arm.com> Tue Jan 07 10:47:58 2020 +0200
tree daa6ddaee050eaa84ccf77a6647498858fec8d75
parent dbf2b43ceb9e6274905c67f51f8507f5dc0e0987

Replace mbedtls_platform_enforce_volatile_reads

Replace function mbedtls_platform_enforce_volatile_reads() with
mbedtls_platform_random_delay().

library/pk.c

diff --git a/library/pk.c b/library/pk.c
index 27276a8..1e991c5 100644
--- a/library/pk.c
+++ b/library/pk.c
@@ -597,7 +597,7 @@
 
     if( ret_fi == UECC_SUCCESS )
     {
-        mbedtls_platform_enforce_volatile_reads();
+        mbedtls_platform_random_delay( 50 );
         if( ret_fi == UECC_SUCCESS )
             return( 0 );
         else

library/platform_util.c

diff --git a/library/platform_util.c b/library/platform_util.c
index 691af71..6c5bd3e 100644
--- a/library/platform_util.c
+++ b/library/platform_util.c
@@ -198,12 +198,6 @@
 #endif /* !MBEDTLS_ENTROPY_HARDWARE_ALT */
 }
 
-void mbedtls_platform_enforce_volatile_reads( void )
-{
-    // Add a small random delay as a counter-measure to fault injection attack.
-    mbedtls_platform_random_delay( 50 );
-}
-
 #if defined(MBEDTLS_HAVE_TIME_DATE) && !defined(MBEDTLS_PLATFORM_GMTIME_R_ALT)
 #include <time.h>
 #if !defined(_WIN32) && (defined(unix) || \

library/x509_crt.c

diff --git a/library/x509_crt.c b/library/x509_crt.c
index fd3fa1a..e624c6d 100644
--- a/library/x509_crt.c
+++ b/library/x509_crt.c
@@ -3043,7 +3043,7 @@
 
         if( ret_fi == 0 )
         {
-            mbedtls_platform_enforce_volatile_reads();
+            mbedtls_platform_random_delay( 50 );
             if( ret_fi == 0 )
                 signature_is_good = X509_SIGNATURE_IS_GOOD;
         }
@@ -3549,7 +3549,7 @@
         if( signature_is_good_fi != X509_SIGNATURE_IS_GOOD )
             *flags |= MBEDTLS_X509_BADCERT_NOT_TRUSTED | X509_BADCERT_FI_EXTRA;
 
-        mbedtls_platform_enforce_volatile_reads();
+        mbedtls_platform_random_delay( 50 );
         if( signature_is_good_fi != X509_SIGNATURE_IS_GOOD )
             *flags |= MBEDTLS_X509_BADCERT_NOT_TRUSTED | X509_BADCERT_FI_EXTRA;
 
@@ -3861,7 +3861,7 @@
     flags_fi = *flags;
     if( flags_fi == 0 )
     {
-        mbedtls_platform_enforce_volatile_reads();
+        mbedtls_platform_random_delay( 50 );
         if( flags_fi == 0 )
             return( 0 );
     }