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From: David Rientjes <rientjes@google.com>
To: Suren Baghdasaryan <surenb@google.com>
Cc: "Minchan Kim" <minchan@kernel.org>,
	"Andrew Morton" <akpm@linux-foundation.org>,
	"Jann Horn" <jannh@google.com>,
	"Kees Cook" <keescook@chromium.org>,
	"Jeffrey Vander Stoep" <jeffv@google.com>,
	"Michal Hocko" <mhocko@suse.com>,
	"Shakeel Butt" <shakeelb@google.com>,
	"Edgar Arriaga García" <edgararriaga@google.com>,
	"Tim Murray" <timmurray@google.com>,
	linux-mm <linux-mm@kvack.org>,
	selinux@vger.kernel.org, "Linux API" <linux-api@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>,
	kernel-team <kernel-team@android.com>
Subject: Re: [PATCH 1/1] mm/madvise: replace ptrace attach requirement for process_madvise
Date: Fri, 8 Jan 2021 17:02:30 -0800 (PST)	[thread overview]
Message-ID: <db29d560-45d9-1eb3-60d0-8d6153ac7193@google.com> (raw)
In-Reply-To: <CAJuCfpHa3XHVEjNBDHJNo3RBWGdLnXsgZH9wyiGLqj655GwE2w@mail.gmail.com>

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!

  reply	other threads:[~2021-01-09  1:03 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-08 20:58 [PATCH 1/1] mm/madvise: replace ptrace attach requirement for process_madvise Suren Baghdasaryan
2021-01-08 22:15 ` Minchan Kim
2021-01-08 22:17   ` Suren Baghdasaryan
2021-01-09  1:02     ` David Rientjes [this message]
2021-01-09  2:19       ` Suren Baghdasaryan
2021-01-11 10:20 ` Florian Weimer
2021-01-11 17:05   ` Suren Baghdasaryan
2021-01-11 17:09     ` Suren Baghdasaryan

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