misc/124410: malloc exposes previously free'd memory

[Garrett Cooper]

On Mon, Jun 9, 2008 at 2:40 AM,  <rene.schickbauer at magnapowertrain.com> wrote:
> The following reply was made to PR misc/124410; it has been noted by GNATS.
>
> From: rene.schickbauer at magnapowertrain.com
> To: bug-followup at FreeBSD.org, rene.schickbauer at magnapowertrain.com
> Cc:
> Subject: Re: misc/124410: malloc exposes previously free'd memory
> Date: Mon, 9 Jun 2008 11:08:13 +0200
>
>  I forgot to mention:
>
>  Yes, i know, there is an option for malloc() to automatically initialize
>  memory to "0".
>
>  But this is doesn't look like it's enough:
>
>  For one thing, it looks like the user may override global setting (is
>  unsetting an option possible?). According to the man-page, the memset() (if
>  option is set) is done in malloc() instead directly in the kernel, and
>  realloc() and reallocf() are not covered at all.
>
>  Also, free()ing memory should wipe it for security reasons, for example it
>  may help against the "RAM freezing hacks", in cases where the application
>  has already free()'d but not malloc()'d security relevant data; see also
>  <http://www.hackaday.com/2008/02/21/breaking-disk-encryption-with-ram-dumps/>

Rene,
Could you provide more info, such as CFLAGS used, CPUTYPE, and gcc
--version please?
Thanks,
-Garrett