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SubjectRe: [PATCH 1/1] mm/madvise: replace ptrace attach requirement for process_madvise
On Fri, 8 Jan 2021, Suren Baghdasaryan wrote:

> > > @@ -1197,12 +1197,22 @@ SYSCALL_DEFINE5(process_madvise, int, pidfd, const struct iovec __user *, vec,
> > > goto release_task;
> > > }
> > >
> > > - mm = mm_access(task, PTRACE_MODE_ATTACH_FSCREDS);
> > > + /* Require PTRACE_MODE_READ to avoid leaking ASLR metadata. */
> > > + mm = mm_access(task, PTRACE_MODE_READ_FSCREDS);
> > > if (IS_ERR_OR_NULL(mm)) {
> > > ret = IS_ERR(mm) ? PTR_ERR(mm) : -ESRCH;
> > > goto release_task;
> > > }
> > >
> > > + /*
> > > + * Require CAP_SYS_NICE for influencing process performance. Note that
> > > + * only non-destructive hints are currently supported.
> > > + */
> > > + if (!capable(CAP_SYS_NICE)) {
> > > + ret = -EPERM;
> > > + goto release_task;
> >
> > mmput?
>
> Ouch! Thanks for pointing it out! Will include in the next respin.
>

With the fix, feel free to add:

Acked-by: David Rientjes <rientjes@google.com>

Thanks Suren!

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