/dev/modem permissions. Help!

/dev/modem permissions. Help!

Post by Ra » Sun, 31 Dec 1899 09:00:00



OK...  This one has been driving me nuts for a long time, both when I
used Red Hat 5.2 and now with SuSE 6.2.

If I log in as anyone other than root, and try to run wvdial, I get
the following message:

cannot open /dev/modem  Permission denied

*HOW* do I fix this?!  I tried making myself members of the groups
"dialout" and "uucp" and even "modem" in addition to my primary
membership in "users", but nothing works!  I keep getting that same
damn message.

How do I change the permissions on the device?!  I tried doing it in
Midnight Commander both on the /dev/modem symlink and on /dev/ttyS3,
but I get no results.  How do I give regular users the ability to
access the modem consistenly?  What config file do I need to change to
allow this?  I'm stunned that neither my SuSE manual nor my Red Hat
Secrets book address such a simple and basic issue.

If I'm logged in as root, no problem.  Wvdial works like a dream.  As
a non-root, mere motral user, no way.

Thanks in advance for any and all help,

Ray

 
 
 

/dev/modem permissions. Help!

Post by Andy Wettstei » Sun, 31 Dec 1899 09:00:00


/dev/ttyS3 should be owned by a certain group  
do an 'ls -l /dev/ttyS3'

you should get something like this:
crw-rw----   1 root     dialout    4,  65 Oct  9 09:19 /dev/ttyS3

if you're already in the group that it says (dialout would be the group here)
then you need to make sure that the group has read/write access to that device.
 the second rw here shows that the group dialout does.  so you'd need to do
something like:
chmod g+rw /dev/ttyS3

changing permission on the symbolic link won't do any good.

later


>OK...  This one has been driving me nuts for a long time, both when I
>used Red Hat 5.2 and now with SuSE 6.2.

>If I log in as anyone other than root, and try to run wvdial, I get
>the following message:

>cannot open /dev/modem  Permission denied

>*HOW* do I fix this?!  I tried making myself members of the groups
>"dialout" and "uucp" and even "modem" in addition to my primary
>membership in "users", but nothing works!  I keep getting that same
>damn message.

>How do I change the permissions on the device?!  I tried doing it in
>Midnight Commander both on the /dev/modem symlink and on /dev/ttyS3,
>but I get no results.  How do I give regular users the ability to
>access the modem consistenly?  What config file do I need to change to
>allow this?  I'm stunned that neither my SuSE manual nor my Red Hat
>Secrets book address such a simple and basic issue.

>If I'm logged in as root, no problem.  Wvdial works like a dream.  As
>a non-root, mere motral user, no way.

>Thanks in advance for any and all help,

>Ray

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/dev/modem permissions. Help!

Post by Ra » Sun, 31 Dec 1899 09:00:00


On Mon, 11 Oct 1999 21:28:31 -0500, Andy Wettstein


>/dev/ttyS3 should be owned by a certain group  
>do an 'ls -l /dev/ttyS3'

>you should get something like this:
>crw-rw----   1 root     dialout    4,  65 Oct  9 09:19 /dev/ttyS3

>if you're already in the group that it says (dialout would be the group here)
>then you need to make sure that the group has read/write access to that device.
> the second rw here shows that the group dialout does.  so you'd need to do
>something like:
>chmod g+rw /dev/ttyS3

>changing permission on the symbolic link won't do any good.

Somehow I kind of figured not.  I'll give your suggestions a try.
Thanks a lot! :-)

Ray

 
 
 

/dev/modem permissions. Help!

Post by Kevin Steffe » Sun, 31 Dec 1899 09:00:00


Try to:
chmod +s /dev/modem
and
chmod o+rw /dev/modem
This gives users the super-user mode on the file.

Kevin Steffer

Den Tue, 12 Oct 1999 skrev Ray:

Quote:>OK...  This one has been driving me nuts for a long time, both when I
>used Red Hat 5.2 and now with SuSE 6.2.

>If I log in as anyone other than root, and try to run wvdial, I get
>the following message:

>cannot open /dev/modem  Permission denied

>*HOW* do I fix this?!  I tried making myself members of the groups
>"dialout" and "uucp" and even "modem" in addition to my primary
>membership in "users", but nothing works!  I keep getting that same
>damn message.

>How do I change the permissions on the device?!  I tried doing it in
>Midnight Commander both on the /dev/modem symlink and on /dev/ttyS3,
>but I get no results.  How do I give regular users the ability to
>access the modem consistenly?  What config file do I need to change to
>allow this?  I'm stunned that neither my SuSE manual nor my Red Hat
>Secrets book address such a simple and basic issue.

>If I'm logged in as root, no problem.  Wvdial works like a dream.  As
>a non-root, mere motral user, no way.

>Thanks in advance for any and all help,

>Ray

 
 
 

/dev/modem permissions. Help!

Post by Ra » Sun, 31 Dec 1899 09:00:00


On Mon, 11 Oct 1999 21:28:31 -0500, Andy Wettstein


>/dev/ttyS3 should be owned by a certain group  
>do an 'ls -l /dev/ttyS3'

>you should get something like this:
>crw-rw----   1 root     dialout    4,  65 Oct  9 09:19 /dev/ttyS3

>if you're already in the group that it says (dialout would be the group here)
>then you need to make sure that the group has read/write access to that device.
> the second rw here shows that the group dialout does.  so you'd need to do
>something like:
>chmod g+rw /dev/ttyS3

This worked out real well, except...  when I disconnect from the Net
(ie, do a Ctrl-C in the wvdial session terminal) the permissions get
set back to the way they were before I issued the command to grant the
group write access (crw-r----).  The change I do isn't permanent.  Any
SuSE 6.2 experts out there know what's going on and how to change
things so the permissions remain after I disconnect?  Thanks...

Ray

 
 
 

/dev/modem permissions. Help!

Post by Oliver.Na » Sun, 31 Dec 1899 09:00:00



> Try to:
> chmod +s /dev/modem
> and
> chmod o+rw /dev/modem
> This gives users the super-user mode on the file.

In my Opioniion that is not a very good idea. Better solution:
Make all users that should be allowed to access the modem members of the group
uucp.

(I assume, that your device-files look like that:)

Quote:> dir /dev/modem /dev/ttyS?

lrwxrwxrwx   1 root     root            5 Okt 11 10:38 /dev/modem -> ttyS0
crw-rw----   1 root     uucp       4,  64 Okt 12 15:20 /dev/ttyS0
crw-rw----   1 root     uucp       4,  65 Mai  1 00:50 /dev/ttyS1
crw-rw----   1 root     uucp       4,  66 Mai  1 00:50 /dev/ttyS2
crw-rw----   1 root     uucp       4,  67 Mai  1 00:50 /dev/ttyS3
crw-rw----   1 root     uucp       4,  68 Mai  1 00:50 /dev/ttyS4
crw-rw----   1 root     uucp       4,  69 Mai  1 00:50 /dev/ttyS5
crw-rw----   1 root     uucp       4,  70 Mai  1 00:50 /dev/ttyS6
crw-rw----   1 root     uucp       4,  71 Mai  1 00:50 /dev/ttyS7
crw-rw----   1 root     uucp       4,  72 Mai  1 00:50 /dev/ttyS8
crw-rw----   1 root     uucp       4,  73 Mai  1 00:50 /dev/ttyS9
 
 
 

/dev/modem permissions. Help!

Post by Bill Unr » Sun, 31 Dec 1899 09:00:00



Quote:>Try to:
>chmod +s /dev/modem
>and
>chmod o+rw /dev/modem
>This gives users the super-user mode on the file.

/dev/modem is not an executable. you cannot run it. The suid bit does
nothing.
Also /dev/modem is almost always a link and permissions mean nothing on
a link.
Find the device that /devmodem points to and do
chmod a+rw /dev/ttyS3
(assuming it points to /dev/ttyS3.
ls -lga /dev/modem
 
 
 

/dev/modem permissions. Help!

Post by Ra » Sun, 31 Dec 1899 09:00:00





>> Try to:
>> chmod +s /dev/modem
>> and
>> chmod o+rw /dev/modem
>> This gives users the super-user mode on the file.

>In my Opioniion that is not a very good idea. Better solution:
>Make all users that should be allowed to access the modem members of the group
>uucp.

>(I assume, that your device-files look like that:)

>> dir /dev/modem /dev/ttyS?
>lrwxrwxrwx   1 root     root            5 Okt 11 10:38 /dev/modem -> ttyS0
>crw-rw----   1 root     uucp       4,  64 Okt 12 15:20 /dev/ttyS0
>crw-rw----   1 root     uucp       4,  65 Mai  1 00:50 /dev/ttyS1
>crw-rw----   1 root     uucp       4,  66 Mai  1 00:50 /dev/ttyS2
>crw-rw----   1 root     uucp       4,  67 Mai  1 00:50 /dev/ttyS3
>crw-rw----   1 root     uucp       4,  68 Mai  1 00:50 /dev/ttyS4
>crw-rw----   1 root     uucp       4,  69 Mai  1 00:50 /dev/ttyS5
>crw-rw----   1 root     uucp       4,  70 Mai  1 00:50 /dev/ttyS6
>crw-rw----   1 root     uucp       4,  71 Mai  1 00:50 /dev/ttyS7
>crw-rw----   1 root     uucp       4,  72 Mai  1 00:50 /dev/ttyS8
>crw-rw----   1 root     uucp       4,  73 Mai  1 00:50 /dev/ttyS9

I did something like this...  I set ttyS3 to:

crw-rw----   1 root     uucp       4,  67 Mai  1 00:50 /dev/ttyS3

but everytime I disconnect from the Net, it gets set back to:

crw-r-----   1 root     uucp       4,  67 Mai  1 00:50 /dev/ttyS3

(the write permission goes away)  Any thoughts as to why this might be
happening?  I'd really like to get this problem resolved once and for
all.  Such a tiny thing, yet so annoying. :-)  I'd like it so I
*don't* have to log in as root and change something everytime I want
to connect to my ISP.

Ray

 
 
 

/dev/modem permissions. Help!

Post by M. Buchenried » Sun, 31 Dec 1899 09:00:00


[Argh. Why , oh why, are there so many misconfigured servers carrying
bogus col.* groups ? ]

[ Non-existant col.help group removed from Newsgroups: line]


>Try to:
>chmod +s /dev/modem
>and
>chmod o+rw /dev/modem
>This gives users the super-user mode on the file.

[...]

Rubbish. Changing the permissions on a symbolic link is absolutely
useless. Change the permissions on the device file the link is pointing
onto instead.

Michael
--

          Lumber Cartel Unit #456 (TINLC) & Official Netscum
    Note: If you want me to send you email, don't munge your address.

 
 
 

/dev/modem permissions. Help!

Post by Tilo Bauma » Sun, 31 Dec 1899 09:00:00



>all.  Such a tiny thing, yet so annoying. :-)  I'd like it so I
>*don't* have to log in as root and change something everytime I want
>to connect to my ISP.

Quite another solution: take sudo (-> man sudo):
sudo allows a permitted user to execute a command as the
superuser

It is easy, secure - I think, and works fine.

--
News per UUCP austauschen unter Linux?
                      yi.com/home/BaumannJoachim/uucp.html

 
 
 

/dev/modem permissions. Help!

Post by zenta » Sun, 31 Dec 1899 09:00:00



>This worked out real well, except...  when I disconnect from the Net
>(ie, do a Ctrl-C in the wvdial session terminal) the permissions get
>set back to the way they were before I issued the command to grant the
>group write access (crw-r----).  The change I do isn't permanent.  Any
>SuSE 6.2 experts out there know what's going on and how to change
>things so the permissions remain after I disconnect?  Thanks...

>Ray

Hey Ray, I found the problem why wvdial can't be used by users, but
only as root. I thought my modem wasn't resetting but I kept searching
for the answer.
Go to http://sdb.suse.de/sdb/en/html/cep_pc_welt_ppp.html

( note: the underscores are hidden by the link, the page is
cep_pc_welt_ppp.html  )

I love Suse, there's always an answer
zentara

P.S. Don't email me, my address isn't valid right now.

 
 
 

1. help with /dev/modem <-> /dev/cua0

I'm new to Linux, and deleted my /dev/modem <-> /dev/cua0 file.
How the hell do I recreate this link?  I was using minicom and
a Segmentation Error poped up and I could no longer access /dev/modem
because it always showed-up as being locked... Since I wasn't
smart enough to just delete /usr/spool/uucp/LCK..modem I deleted
/dev/modem instead.  Now I can use minicom with /dev/cua0 only.
Can someone help me out here?

Thanks a bunch!
--
Michael Gercevich  --  PC/Network Analyst  --  Squire, Sanders & Dempsey |

           Heh,Heh...Heh,Heh...Heh.        We're there, dude.            |
_____________I hate things that suck! - Beavis_&_Butthead________________|

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