From: Stephen Hemminger <stephen@networkplumber.org>
To: Dmitry Kozlyuk <dmitry.kozliuk@gmail.com>
Cc: dev@dpdk.org, stable@dpdk.org,
Boris Ouretskey <borisusun@gmail.com>,
Isaac Boukris <iboukris@gmail.com>,
Bruce Richardson <bruce.richardson@intel.com>
Subject: Re: [PATCH] doc: add capability to access physical addresses
Date: Sat, 14 Jan 2023 18:27:52 -0800 [thread overview]
Message-ID: <20230114182752.0fa60bf7@hermes.local> (raw)
In-Reply-To: <20230114225802.136625-1-dmitry.kozliuk@gmail.com>
On Sun, 15 Jan 2023 01:58:02 +0300
Dmitry Kozlyuk <dmitry.kozliuk@gmail.com> wrote:
> CAP_DAC_OVERRIDE capability is required to access /proc/self/pagemap,
> but it was missing from the Linux guide, causing issues for users.
>
> Fixes: 979bb5d493fb ("doc: add more instructions for running as non-root")
> Cc: stable@dpdk.org
>
> Signed-off-by: Dmitry Kozlyuk <dmitry.kozliuk@gmail.com>
> Reported-by: Boris Ouretskey <borisusun@gmail.com>
> Reported-by: Isaac Boukris <iboukris@gmail.com>
DAC_OVERRIDE is like having the master key. It opens all doors
and if so, running as non-root really doesn't matter that much.
Ideally, a finer grain permission could be used.
Recommending this to users seems wrong.
According proc.5 man page.
/proc/[pid]/pagemap (since Linux 2.6.25)
This file shows the mapping of each of the process's
virtual pages into physical page frames or swap area.
...
Permission to access this file is governed by a ptrace
access mode PTRACE_MODE_READ_FSCREDS check; see ptrace(2).
Which distro is this? What security module are you using.
For example, on Debian (kernel 5.17) running as non-root it is possible to read pagemap.
next prev parent reply other threads:[~2023-01-15 2:27 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-14 22:58 Dmitry Kozlyuk
2023-01-15 2:27 ` Stephen Hemminger [this message]
2023-01-15 6:20 ` Isaac Boukris
2023-01-15 12:46 ` Dmitry Kozlyuk
2023-01-15 13:30 ` Isaac Boukris
2023-01-19 21:24 Dmitry Kozlyuk
2023-03-28 19:19 ` Thomas Monjalon
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