On Sat, Sep 23, 2017 at 02:05:34PM +0000, Otto Moerbeek wrote: > On Sat, Sep 23, 2017 at 05:28:57AM -0400, Ted Unangst wrote: > > > Otto Moerbeek wrote: > > > Hi, > > > > > > Malloc maintains a list if 16 slots of chunks to be freed. On free a > > > chunk is put in a random slot and the existing chunk in that slot is > > > actually freed. Currently, the code only checks the slot selected for > > > a double free. > > > > > > This diff adds code to check all slots. It also removes the option to > > > disable delayed free. > > > > I thought we were already doing this, so ok. :) > > And here's the manpage diff. > > -Otto > > Index: malloc.conf.5 > =================================================================== > RCS file: /cvs/src/share/man/man5/malloc.conf.5,v > retrieving revision 1.11 > diff -u -p -r1.11 malloc.conf.5 > --- malloc.conf.5 31 Oct 2016 10:07:18 -0000 1.11 > +++ malloc.conf.5 23 Sep 2017 14:04:14 -0000 > @@ -56,18 +56,11 @@ at exit. > This option requires the library to have been compiled with -DMALLOC_STATS in > order to have any effect. > .It Cm F > -.Dq Freeguard . > -Enable use after free detection. > +.Dq Freecheck . > +Enable more extenisve double free and use after free detection.
with s/extenisve/extensive ok tb (as is the .c diff) > +All chunks in the delayed free list will be checked for double frees. > Unused pages on the freelist are read and write protected to > cause a segmentation fault upon access. > -This will also switch off the delayed freeing of chunks, > -reducing random behaviour but detecting double > -.Xr free 3 > -calls as early as possible. > -This option is intended for debugging rather than improved security > -(use the > -.Cm U > -option for security). > .It Cm G > .Dq Guard . > Enable guard pages. >
