Re: Weird behavior with /dev/mem

From: Daniel C. Sobral <dcs_at_tcoip.com.br>
Date: Fri, 31 Oct 2003 17:44:32 -0200
Doug White wrote:
> On Fri, 31 Oct 2003, Daniel C. Sobral wrote:
> 
> 
>>Weird thing. I updated my system today (October 31), and now I can't
>>list routes from syscons. But I still can list routes from Konsole, on
>>X. Following a suggestion by Genesys, I checked permissions of /dev/mem
>>and netstat and... for some reason, I can't stat /dev/mem under syscons!
> 
> 
> You didn't mount that filesystem nosuid, did you?

No. And, as a matter of fact, the error is user-agnostic. In fact, in 
the example below the problem happen with the root user, while user dcs 
is home free.

MMmmmm... I know what it is. It's something with mac, because X is run 
with /usr/sbin/setpmac mls/equal. (tests) Yep, that's it.

Ok, rwatson, it's all your fault. Sneaky, sneaky.

> 
> 
>>Here are a couple of typescripts I got:
>>
>>[0] dcs_at_dcs:/opt/home/dcs$ cat from_konsole
>>Script started on Fri Oct 31 17:25:04 2003
>>dcs_at_dcs:/opt/home/dcs$ ls -ld /dev
>>dr-xr-xr-x  4 root  wheel  512 Oct 31 13:56 /dev
>>dcs_at_dcs:/opt/home/dcs$ ls -l /dev/mem
>>crw-r-----  1 root  kmem    2,   0 Oct 31 15:54 /dev/mem
>>dcs_at_dcs:/opt/home/dcs$ ls -l /usr/bin/netstat
>>-r-xr-sr-x  1 root  kmem  108664 Oct 31 13:18 /usr/bin/netstat
>>dcs_at_dcs:/opt/home/dcs$ netstat -nr
>>Routing tables
>>
>>Internet:
>>Destination        Gateway            Flags    Refs      Use  Netif Expire
>>default            10.0.11.1          UGSc        0        0   fxp0
>>10/16              link#1             UC          0        0   fxp0
>>10.0.2.72          00:04:23:2a:13:7b  UHLW        0        1   fxp0    881
>>10.0.11.1          00:10:54:cd:58:40  UHLW       28        0   fxp0   1197
>>10.0.12.131        00:01:30:26:e0:00  UHLW        0        0   fxp0   1186
>>10.0.14.20         00:02:55:58:22:0a  UHLW        6    39928   fxp0    975
>>127.0.0.1          127.0.0.1          UH          0        6    lo0
>>dcs_at_dcs:/opt/home/dcs$ exit
>>exit
>>
>>Script done on Fri Oct 31 17:25:20 2003
>>[0] dcs_at_dcs:/opt/home/dcs$ cat from_syscons
>>Script started on Fri Oct 31 17:26:01 2003
>>root_at_dcs:/root$ ls -ld /dev
>>dr-xr-xr-x  4 root  wheel  512 Oct 31 13:56 /dev
>>root_at_dcs:/root$ ls -l /dev/mem
>>ls: /dev/mem: Permission denied
>>root_at_dcs:/root$ ls -l /usr/bin/netstat
>>-r-xr-sr-x  1 root  kmem  108664 Oct 31 13:18 /usr/bin/netstat
>>root_at_dcs:/root$ netstat -nr
>>netstat: kvm not available
>>Routing tables
>>rt_tables: symbol not in namelist
>>root_at_dcs:/root$ exit
>>exit
>>
>>Script done on Fri Oct 31 17:26:18 2003
>>[0] dcs_at_dcs:/opt/home/dcs$ which ls
>>/bin/ls
>>[0] dcs_at_dcs:/opt/home/dcs$ type ls
>>ls is aliased to `ls -G'
>>[0] dcs_at_dcs:/opt/home/dcs$ unalias ls
>>[0] dcs_at_dcs:/opt/home/dcs$ ls -l /dev/mem
>>crw-r-----  1 root  kmem    2,   0 Oct 31 15:54 /dev/mem
>>
>>I'm CCing phk on the grounds of Mr Devfs, and Sam as I blamed the
>>networking code earlier... :-)
>>
>>
> 
> 


-- 
Daniel C. Sobral                   (8-DCS)
Gerencia de Operacoes
Divisao de Comunicacao de Dados
Coordenacao de Seguranca
VIVO Centro Oeste Norte
Fones: 55-61-313-7654/Cel: 55-61-9618-0904
E-mail: Daniel.Capo_at_tco.net.br
         Daniel.Sobral_at_tcoip.com.br
         dcs_at_tcoip.com.br

Outros:
	dcs_at_newsguy.com
	dcs_at_freebsd.org
	capo_at_notorious.bsdconspiracy.net

Ten years of rejection slips is nature's
way of telling you to stop writing.
		-- R. Geis
Received on Fri Oct 31 2003 - 10:44:39 UTC

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