> 
> Message: 1
> Date: Sun, 13 Jan 2013 10:05:16 -0500
> From: Richard <[email protected]>
> Subject: [blfs-support] Two strange things related to Xorg (I think)
> To: [email protected]
> Message-ID: <[email protected]>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
> 
> 
> I have built LFS-7.2 and have added packages
> according to a version of the BLFS book that
> says it is compatible with LFS-7.2. I have
> installed Xorg-7.7 along with the required
> and recommended dependencies. When I start
> Xorg I observe some strange behavior, I
> am hoping somebody can give me an idea why
> this occurs and how I might prevent it.
> 
> The first thing is that after I start X,
> I intermittently get a window-full of
> messages like this:
> 
> ----------------------------------------
> OS Function mkdir declared
> OS Attempting to declare FFI  mkstemp
> OS Function mkstemp declared
> OS Attempting to declare FFI  open
> OS Function open declared
> OS Attempting to declare FFI  opendir
> OS Function opendir declared
> OS Attempting to declare FFI  pread
> OS Function pread declared
> OS Attempting to declare FFI  pwrite
> OS Function pwrite declared
> OS Attempting to declare FFI  read
> OS Function read declared
> OS Attempting to declare FFI  readdir
> OS Function readdir declared
> OS Attempting to declare FFI  rename
> OS Function rename declared
> OS Attempting to declare FFI  rmdir
> OS Function rmdir declared
> OS Attempting to declare FFI  splice
> OS Function splice declared
> OS Attempting to declare FFI  strerror
> OS Function strerror declared
> OS Attempting to declare FFI  symlink
> OS Function symlink declared
> OS Attempting to declare FFI  truncate
> OS Function truncate declared
> OS Attempting to declare FFI  unlink
> OS Function unlink declared
> OS Attempting to declare FFI  write
> OS Function write declared
> OS Attempting to declare FFI  pipe
> OS Function pipe declared
> --------------------------------------
> 
> I am guessing this is related to
> libffi-3.0.11, which I installed as
> a recommended dependency of LLVM-3.1,
> which in turn was a recommended dependency
> of MesaLib-9.0. Any ideas why I am getting
> this?
> 

I was wrong about this being related to Xorg
or libffi -- I discovered instead that it is
a problem with firefox-16.0.1, which is actually
logging these messages. There is a bug I found
on mozilla Bugzilla, number 785200, which deals
with this issue. There is also an associated
patch. Unfortunately I was not able to apply
the patch directly, it appears to refer to
slightly different filenames than I have in my
firefox build directory. However I was able to
manually edit the files according to the changes
indicated in the patch. The files that must be
modified are:

mozilla-release/toolkit/components/osfile/osfile_shared.jsm
mozilla-release/toolkit/components/osfile/osfile_unix_back.jsm

After making the changes in the patch and re-building
firefox-16.0.1, the above messages disappeared.

I found this bug by searching on google -- on the
ftp.mozilla.org site I found all the versions of
firefox, but no mention of applicable bugs or
patches for each version. Did I just miss this
information, is it located somewhere on the
mozilla site?


> --------------------------------------------
> 
> The second thing that happens is when I try to
> set up a firewall using iptables so that local
> messages even from 127.0.0.1 are not accepted.
> I did this in LFS-6.2 without any apparent
> problems, and in fact one of the HOWTO's
> suggests that you do this. However when I
> block local messages I get the following when
> I type startx:
> 
> ---------------------------------------------------
> [ 3886.542624] FIREWALL:INPUT IN=lo OUT= 
> MAC=00:00:00:00:00:00:00:00:00:00:00:00:08:00 SRC=127.0.0.1 
> DST=127.0.0.1 LEN=53 TOS=0x00 PREC=0x00 TTL=64 ID=47598 DF PROTO=UDP
> SPT=34531 DPT=53 LEN=33
> [ 3886.557503] FIREWALL:INPUT IN=lo OUT= 
> MAC=00:00:00:00:00:00:00:00:00:00:00:00:08:00 SRC=127.0.0.1 
> DST=127.0.0.1 LEN=53 TOS=0x00 PREC=0x00 TTL=64 ID=47599 DF PROTO=UDP
> SPT=34531 DPT=53 LEN=33
> [ 3891.577950] FIREWALL:INPUT IN=lo OUT= 
> MAC=00:00:00:00:00:00:00:00:00:00:00:00:08:00 SRC=127.0.0.1 
> DST=127.0.0.1 LEN=53 TOS=0x00 PREC=0x00 TTL=64 ID=47600 DF PROTO=UDP
> SPT=34531 DPT=53 LEN=33
> [ 3891.594048] FIREWALL:INPUT IN=lo OUT= 
> MAC=00:00:00:00:00:00:00:00:00:00:00:00:08:00 SRC=127.0.0.1 
> DST=127.0.0.1 LEN=53 TOS=0x00 PREC=0x00 TTL=64 ID=47601 DF PROTO=UDP
> SPT=34531 DPT=53 LEN=33
> ---------------------------------------------------
> 
> This occurs before X actually starts, and I keep getting these
> messages until I type Ctrl-C. At that point Xorg seems to start
> up normally. Is there any way I can avoid this (other than
> allowing local messages to get through the firewall)?
> 
> 
> 
> Message: 2
> Date: Sun, 13 Jan 2013 12:13:30 -0600
> From: Bruce Dubbs <[email protected]>
> Subject: Re: [blfs-support] Two strange things related to Xorg (I
>       think)
> To: BLFS Support List <[email protected]>
> Message-ID: <[email protected]>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
> 
> 
> 
> Try disabling xdmcp with
> 
> startx -- -nolisten tcp
> 
>     -- Bruce
> 

   I tried this but it didn't make any difference.
Is it likely that xdmcp is enabled on my system? I
read that it is usually disabled by default because
it is not secure, and I have not done anything to
intentionally enable it. Is there a way I can tell
if it is enabled on my system?

Anyway I have become resigned to allowing traffic
on the loopback interface through my firewall.
However, I am concerned about the way this is
done in the /etc/rc.d/rc.iptables file suggested
in the BLFS book. If I include the following rule:

# Allow local-only connections
iptables -A INPUT  -i lo -j ACCEPT

then I get for INPUT:

-----------------------------------------------------
iptables -L
Chain INPUT (policy DROP)
target     prot opt source               destination
ACCEPT     all  --  anywhere             anywhere
ACCEPT     all  --  anywhere             anywhere             ctstate 
RELATED,ESTABLISHED
LOG        all  --  anywhere             anywhere             LOG level 
warning prefix "FIREWALL:INPUT "
----------------------------------------------------

Doesn't this mean that packets from *anywhere* will be accepted??

On the other hand, if I use:

# Allow local-only connections
iptables -A INPUT -i lo -s 127.0.0.1 -d 127.0.0.1 -j ACCEPT

then I get for INPUT:

iptables -L
Chain INPUT (policy DROP)
target     prot opt source               destination
ACCEPT     all  --  localhost            localhost
ACCEPT     all  --  anywhere             anywhere             ctstate 
RELATED,ESTABLISHED
LOG        all  --  anywhere             anywhere             LOG level 
warning prefix "FIREWALL:INPUT "

Isn't this what I want?

By allowing communication on 127.0.0.1 I no longer get the
above messages on startx.

Richard

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