mbedtls_timing_get_timer: don't use uninitialized memory
mbedtls_timing_get_timer with reset=1 is called both to initialize a
timer object and to reset an already-initialized object. In an
initial call, the content of the data structure is indeterminate, so
the code should not read from it. This could crash if signed overflows
trap, for example.
As a consequence, on reset, we can't return the previously elapsed
time as was previously done on Windows. Return 0 as was done on Unix.
diff --git a/library/timing.c b/library/timing.c
index 4576f31..a6067d0 100644
--- a/library/timing.c
+++ b/library/timing.c
@@ -244,21 +244,23 @@
unsigned long mbedtls_timing_get_timer( struct mbedtls_timing_hr_time *val, int reset )
{
- unsigned long delta;
- LARGE_INTEGER offset, hfreq;
struct _hr_time *t = (struct _hr_time *) val;
- QueryPerformanceCounter( &offset );
- QueryPerformanceFrequency( &hfreq );
-
- delta = (unsigned long)( ( 1000 *
- ( offset.QuadPart - t->start.QuadPart ) ) /
- hfreq.QuadPart );
-
if( reset )
+ {
QueryPerformanceCounter( &t->start );
-
- return( delta );
+ return( 0 );
+ }
+ else
+ {
+ unsigned long delta;
+ LARGE_INTEGER now, hfreq;
+ QueryPerformanceCounter( &now );
+ QueryPerformanceFrequency( &hfreq );
+ delta = (unsigned long)( ( now.QuadPart - t->start.QuadPart ) * 1000ul
+ / hfreq.QuadPart );
+ return( delta );
+ }
}
/* It's OK to use a global because alarm() is supposed to be global anyway */
@@ -285,23 +287,22 @@
unsigned long mbedtls_timing_get_timer( struct mbedtls_timing_hr_time *val, int reset )
{
- unsigned long delta;
- struct timeval offset;
struct _hr_time *t = (struct _hr_time *) val;
- gettimeofday( &offset, NULL );
-
if( reset )
{
- t->start.tv_sec = offset.tv_sec;
- t->start.tv_usec = offset.tv_usec;
+ gettimeofday( &t->start, NULL );
return( 0 );
}
-
- delta = ( offset.tv_sec - t->start.tv_sec ) * 1000
- + ( offset.tv_usec - t->start.tv_usec ) / 1000;
-
- return( delta );
+ else
+ {
+ unsigned long delta;
+ struct timeval now;
+ gettimeofday( &now, NULL );
+ delta = ( now.tv_sec - t->start.tv_sec ) * 1000ul
+ + ( now.tv_usec - t->start.tv_usec ) / 1000;
+ return( delta );
+ }
}
static void sighandler( int signum )
