On 01/12, Michal Hocko wrote: > > On Mon 11-01-21 09:06:22, Suren Baghdasaryan wrote: > > > What we want is the ability for one process to influence another process > > in order to optimize performance across the entire system while leaving > > the security boundary intact. > > Replace PTRACE_MODE_ATTACH with a combination of PTRACE_MODE_READ > > and CAP_SYS_NICE. PTRACE_MODE_READ to prevent leaking ASLR metadata > > and CAP_SYS_NICE for influencing process performance. > > I have to say that ptrace modes are rather obscure to me. So I cannot > really judge whether MODE_READ is sufficient. My understanding has > always been that this is requred to RO access to the address space. But > this operation clearly has a visible side effect. Do we have any actual > documentation for the existing modes? > > I would be really curious to hear from Jann and Oleg (now Cced). Can't comment, sorry. I never understood these security checks and never tried. IIUC only selinux/etc can treat ATTACH/READ differently and I have no idea what is the difference. Oleg.
