On Fri, Jul 11, 2014 at 01:38:23AM -0600, Theo de Raadt wrote:
> I am a bit concerned. The description is trying too hard to be overly
> precise, and may be cumbersome for the typical reader of this page.
indeed, and I also dislike putting too much implementation details
into a man page. Things might change and if you are really interested,
read the code.
-Otto
>
> > Index: lib/libc/stdlib/malloc.3
> > ===================================================================
> > RCS file: /cvs/src/lib/libc/stdlib/malloc.3,v
> > retrieving revision 1.78
> > diff -u -p -d -r1.78 malloc.3
> > --- lib/libc/stdlib/malloc.3 1 May 2014 18:41:59 -0000 1.78
> > +++ lib/libc/stdlib/malloc.3 11 Jul 2014 07:19:27 -0000
> > @@ -220,10 +220,23 @@ Malloc will first look for a symbolic li
> > .Pa /etc/malloc.conf
> > and next check the environment for a variable called
> > .Ev MALLOC_OPTIONS
> > +(if not
> > +.Xr issetugid 2 )
> > and finally for the global variable
> > .Va malloc_options
> > and scan them for flags in that order.
> > Flags are single letters, uppercase means on, lowercase means off.
> > +.Pp
> > +The default flags are
> > +.Cm A
> > +and
> > +.Cm P ,
> > +small chunks are always junked, and the first
> > +part of the pages is junked after free.
> > +The default junk behavior does not correspond to
> > +.Cm j
> > +or
> > +.Cm J .
> > .Bl -tag -width indent
> > .It Cm A
> > .Dq Abort .
> > @@ -271,6 +284,7 @@ Currently junk is bytes of 0xd0 when all
> > .Dq Duh .
> > \&:-)
> > Freed chunks are filled with 0xdf.
> > +This performs more junking than by default.
> > .It Cm j
> > .Dq Don't Junk .
> > By default, small chunks are always junked, and the first part of pages
> > @@ -297,6 +311,11 @@ This can substantially aid in compacting
> > .\"Consult the source for this one.
> > .It Cm S
> > Enable all options suitable for security auditing.
> > +This currently enables flags
> > +.Cm U ,
> > +.Cm J ,
> > +.Cm G
> > +and sets the free cache page size to 0.
> > .It Cm U
> > .Dq Free unmap .
> > Enable use after free protection for larger allocations.
> >
