[Bug 21573] New: Need heap overrun detection at beginning of buffers, too

http://bugs.winehq.org/show_bug.cgi?id=21573

Summary: Need heap overrun detection at beginning of buffers,
                    too
           Product: Wine
           Version: 1.1.37
          Platform: x86
        OS/Version: Linux
            Status: NEW
          Severity: enhancement
          Priority: P2
         Component: ntdll
        AssignedTo: [e-mail]
        ReportedBy: [e-mail]

On Linux, valgrind gives nice warnings when you access before
the first byte.  It'd be nice if valgrinding Windows apps under Wine
gave the same warnings.  For instance, the following program should
give three warnings under valgrind+wine just as it does under valgrind:

#include <stdio.h>
#include <stdlib.h>

int badness_before_n_after ( char* p )
{
 return p[-1] + p[10];
}

int main ( void )
{
 char* p = malloc(10);
 int who_knows = badness_before_n_after(p);
 // expect 2 x invalid address yelpage
 who_knows += p[5];
 if (who_knows == 42)
   printf("It's 42 (!)\n");
 else
   printf("It's not 42 (dull but unsurprising)\n");
 free(p);
 return 0;
}