On Mon, Mar 15, 2021 at 09:16:26AM -0700, Kees Cook wrote: > On Mon, Mar 15, 2021 at 01:24:10PM +0100, Uladzislau Rezki wrote: > > On Mon, Mar 15, 2021 at 11:04:42AM +0200, Topi Miettinen wrote: > > > What's the problem with that? It seems to me that nothing relies on specific > > > addresses of the chunks, so it should be possible to randomize these too. > > > Also the alignment is honored. > > > > > My concern are: > > > > - it is not a vmalloc allocator; > > - per-cpu allocator allocates chunks, thus it might be it happens only once. It does not allocate it often; > > That's actually the reason to randomize it: if it always ends up in the > same place at every boot, it becomes a stable target for attackers. > Probably we can randomize a base address only once when pcpu-allocator allocates a fist chunk during the boot. > > - changing it will likely introduce issues you are not aware of; > > - it is not supposed to be interacting with vmalloc allocator. Read the > > comment under pcpu_get_vm_areas(); > > > > Therefore i propose just not touch it. > > How about splitting it from this patch instead? Then it can get separate > testing, etc. > It should be split as well as tested. -- Vlad Rezki
