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| <== Date ==> | <== Thread ==> |
|---|
| Subject: | Re: setcap and nosuid |
| From: | "Siddons, David via Tech-talk" <tech-talk at aps.anl.gov> |
| To: | Michael Davidsaver <mdavidsaver at gmail.com> |
| Cc: | EPICS Tech-Talk <tech-talk at aps.anl.gov> |
| Date: | Tue, 2 Feb 2021 18:49:54 +0000 |
|
Well, everything works fine when running as root. I am just being encouraged to stop doing that
🙂
Pete.
From: Michael Davidsaver <mdavidsaver at gmail.com>
Sent: Tuesday, February 2, 2021 1:48 PM To: Siddons, David <siddons at bnl.gov> Cc: EPICS Tech-Talk <tech-talk at aps.anl.gov> Subject: Re: setcap and nosuid On 2/2/21 10:09 AM, Siddons, David wrote:
> Hi Michael, > Setting 0666 doesn't help. Maybe your kernel doesn't have /dev/mem enabled either? > $ grep DEVMEM /boot/config-5.9.0-0.bpo.5-amd64 > CONFIG_DEVMEM=y > CONFIG_ARCH_HAS_DEVMEM_IS_ALLOWED=y > CONFIG_STRICT_DEVMEM=y > CONFIG_IO_STRICT_DEVMEM=y > THanks for the link. I missed that before. It looks like the right way to go. I'll dig into it. > > Pete. > > > ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ > *From:* Michael Davidsaver <mdavidsaver at gmail.com> > *Sent:* Tuesday, February 2, 2021 12:13 PM > *To:* Siddons, David <siddons at bnl.gov> > *Cc:* EPICS Tech-Talk <tech-talk at aps.anl.gov> > *Subject:* Re: setcap and nosuid > > On 2/2/21 8:57 AM, Siddons, David wrote: >> Hi David, >> Yes, I saw that. Changing it doesn't seem to help: >> >> sudo chmod g+w /dev/mem >> ls -l /dev/mem >> crw-rw---- 1 root kmem 1, 1 Feb 1 21:05 /dev/mem >> >> ./regrw R 1 ( a program which maps the FPGA registers to userspace) >> Reading Register 1 >> Can't open /dev/mem > > Have you tried chmod 0666 to make sure this is really a permission problem? > The "Can't open" could also print 'errno'. > > Also, I feel obligated to repeat myself in recommending against using > /dev/mem in any kind of long term solution. There are safer ways > to grant access to specific MMIO ranges. > > https://epics.anl.gov/tech-talk/2020/msg02201.php <https://epics.anl.gov/tech-talk/2020/msg02201.php> |