From: ebiederm@xmission.com (Eric W. Biederman)
To: James Morris <jmorris@namei.org>
Cc: linux-security-module@vger.kernel.org, Jake Edge <jake@lwn.net>,
Arjan van de Ven <arjan@infradead.org>,
Eric Paris <eparis@redhat.com>,
Alan Cox <alan@lxorguk.ukuu.org.uk>,
Roland McGrath <roland@redhat.com>,
mingo@redhat.com, Andrew Morton <akpm@linux-foundation.org>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] proc: avoid leaking eip, esp, or wchan to non-privileged processes (fwd)
Date: Sun, 03 May 2009 23:09:24 -0700 [thread overview]
Message-ID: <m1r5z5jt63.fsf@fess.ebiederm.org> (raw)
In-Reply-To: <alpine.LRH.2.00.0905040917240.20251@tundra.namei.org> (James Morris's message of "Mon\, 4 May 2009 09\:27\:29 +1000 \(EST\)")
James Morris <jmorris@namei.org> writes:
> diff --git a/fs/proc/base.c b/fs/proc/base.c
> index aa763ab..cd3c0d7 100644
> --- a/fs/proc/base.c
> +++ b/fs/proc/base.c
> @@ -319,6 +319,9 @@ static int proc_pid_wchan(struct task_struct *task, char
> *buffer)
> unsigned long wchan;
> char symname[KSYM_NAME_LEN];
>
> + if (!ptrace_may_access(task, PTRACE_MODE_READ))
> + return 0;
> +
> wchan = get_wchan(task);
>
> if (lookup_symbol_name(wchan, symname) < 0)
If the symbol is in the kernel it should be safe to return it's
name, all that is an information leak of a different sort.
Overall I expect we should return -EPERM here and not simply
an empty file.
Have you tested these patches against ps top and similar common
tools?
Eric
next prev parent reply other threads:[~2009-05-04 6:09 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-05-03 23:27 [PATCH] proc: avoid leaking eip, esp, or wchan to non-privileged processes (fwd) James Morris
2009-05-03 23:58 ` Arjan van de Ven
2009-05-04 1:11 ` Jake Edge
2009-05-04 14:38 ` Greg KH
2009-05-04 6:09 ` Eric W. Biederman [this message]
2009-05-04 13:22 ` Jake Edge
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