DragonFly On-Line Manual Pages

PWS_STR_MEMNUKE(3)    DragonFly Library Functions Manual    PWS_STR_MEMNUKE(3)

NAME
     pws_str_memnuke - Over-write the contents of a memory buffer with zeros

LIBRARY
     -lpwstor

SYNOPSIS
     #include <pwstor.h>

     void
     pws_str_memnuke(volatile void *b, size_t sz);

DESCRIPTION
     The function pws_str_memnuke() will over-write sz bytes of memory from
     the pointer referenced by b with zeros.  This is useful for clearing a
     memory buffer which contained, for example, a clear-text password.  Calls
     to free() do not zero the memory, so another application could
     conceivably allocate memory which contains sensitive data from another
     application.  Calling pws_str_memnuke() on the buffer prior to calling
     free() on it will prevent this potentially dangerous condition.

CAVEATS
     The pws_str_memnuke() function cannot indicate an error, for example if
     it returns prematurely because a null-pointer was passed to it.  It
     requires that b be cast (volatile) in order to prevent compilers from
     optimizing it out so that memory is safely wiped.

SEE ALSO
     pwstor(3)

DragonFly 6.5-DEVELOPMENT      October 23, 2008      DragonFly 6.5-DEVELOPMENT