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Stanislaw Kaminski

2008-Jul-14 14:26 UTC

EOL in stderr of ssh - Linux

Hello everyone,
recently I've found something I consider a bug.

Correct me if I'm wrong, but I always thought that Linux' EOL is 0x0A.
Imagine my surprise when I saw that all messages that are being output
on to the stderr (on any Linux I've tested - Fedora and Ubuntu) are
terminated with 0x0D, 0x0A.

Maybe that's standard behaviour of all stderr messages in all Linux
software, but I have to admin it's the first time I saw something like
this.

So, can anybody tell me if it's for a purpose, or is it just a plain bug?

yours sincerely,
Stanislaw Kaminski

Peter Stuge

2008-Jul-14 15:31 UTC

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EOL in stderr of ssh - Linux

On Mon, Jul 14, 2008 at 04:26:47PM +0200, Stanislaw Kaminski
wrote:> Imagine my surprise when I saw that all messages that are being output
> on to the stderr (on any Linux I've tested - Fedora and Ubuntu) are
> terminated with 0x0D, 0x0A.
How are you testing this?

> So, can anybody tell me if it's for a purpose, or is it just a plain
bug?
I doubt ssh has \r\n in any source files.


//Peter

Knox, Bill

2008-Jul-14 16:06 UTC

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EOL in stderr of ssh - Linux

Not on my Fedora Core 7 or my CentOS 5.2 box - both of them terminate
with just 0x0A, as is shown below:

ssh -v 2>&1 | xxd
0000000: 4f70 656e 5353 485f 342e 3370 322c 204f  OpenSSH_4.3p2, O
0000010: 7065 6e53 534c 2030 2e39 2e38 6220 3034  penSSL 0.9.8b 04
0000020: 204d 6179 2032 3030 360a 7573 6167 653a   May 2006.usage:
0000030: 2073 7368 205b 2d31 3234 3641 6143 6667   ssh [-1246AaCfg
0000040: 6b4d 4e6e 7173 5474 5676 5878 595d 205b  kMNnqsTtVvXxY] [
0000050: 2d62 2062 696e 645f 6164 6472 6573 735d  -b bind_address]
0000060: 205b 2d63 2063 6970 6865 725f 7370 6563   [-c cipher_spec
0000070: 5d0a 2020 2020 2020 2020 2020 205b 2d44  ].           [-D
0000080: 205b 6269 6e64 5f61 6464 7265 7373 3a5d   [bind_address:]
0000090: 706f 7274 5d20 5b2d 6520 6573 6361 7065  port] [-e escape
00000a0: 5f63 6861 725d 205b 2d46 2063 6f6e 6669  _char] [-F confi
00000b0: 6766 696c 655d 0a20 2020 2020 2020 2020  gfile].
00000c0: 2020 5b2d 6920 6964 656e 7469 7479 5f66    [-i identity_f
00000d0: 696c 655d 205b 2d4c 205b 6269 6e64 5f61  ile] [-L [bind_a
00000e0: 6464 7265 7373 3a5d 706f 7274 3a68 6f73  ddress:]port:hos
00000f0: 743a 686f 7374 706f 7274 5d0a 2020 2020  t:hostport].
0000100: 2020 2020 2020 205b 2d6c 206c 6f67 696e         [-l login
0000110: 5f6e 616d 655d 205b 2d6d 206d 6163 5f73  _name] [-m mac_s
0000120: 7065 635d 205b 2d4f 2063 746c 5f63 6d64  pec] [-O ctl_cmd
0000130: 5d20 5b2d 6f20 6f70 7469 6f6e 5d20 5b2d  ] [-o option] [-
0000140: 7020 706f 7274 5d0a 2020 2020 2020 2020  p port].
0000150: 2020 205b 2d52 205b 6269 6e64 5f61 6464     [-R [bind_add
0000160: 7265 7373 3a5d 706f 7274 3a68 6f73 743a  ress:]port:host:
0000170: 686f 7374 706f 7274 5d20 5b2d 5320 6374  hostport] [-S ct
0000180: 6c5f 7061 7468 5d0a 2020 2020 2020 2020  l_path].
0000190: 2020 205b 2d77 2074 756e 6e65 6c3a 7475     [-w tunnel:tu
00001a0: 6e6e 656c 5d20 5b75 7365 7240 5d68 6f73  nnel] [user@]hos
00001b0: 746e 616d 6520 5b63 6f6d 6d61 6e64 5d0a  tname [command].

                          Bill Knox
                          Lead Infosec Engineer/Scientist
                          The MITRE Corporation


-----Original Message-----
From: openssh-unix-dev-bounces+wknox=mitre.org at mindrot.org
[mailto:openssh-unix-dev-bounces+wknox=mitre.org at mindrot.org] On Behalf
Of Stanislaw Kaminski
Sent: Monday, July 14, 2008 10:27 AM
To: openssh-unix-dev at mindrot.org
Subject: EOL in stderr of ssh - Linux

Hello everyone,
recently I've found something I consider a bug.

Correct me if I'm wrong, but I always thought that Linux' EOL is 0x0A.
Imagine my surprise when I saw that all messages that are being output
on to the stderr (on any Linux I've tested - Fedora and Ubuntu) are
terminated with 0x0D, 0x0A.

Maybe that's standard behaviour of all stderr messages in all Linux
software, but I have to admin it's the first time I saw something like
this.

So, can anybody tell me if it's for a purpose, or is it just a plain
bug?

yours sincerely,
Stanislaw Kaminski
_______________________________________________
openssh-unix-dev mailing list
openssh-unix-dev at mindrot.org
https://lists.mindrot.org/mailman/listinfo/openssh-unix-dev

Bob Proulx

2008-Jul-14 21:19 UTC

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EOL in stderr of ssh - Linux

Stanislaw Kaminski wrote:> Correct me if I'm wrong, but I always thought that Linux' EOL is
0x0A.
> Imagine my surprise when I saw that all messages that are being output
> on to the stderr (on any Linux I've tested - Fedora and Ubuntu) are
> terminated with 0x0D, 0x0A.
What are your tty settings?  What is the output of this command?

  stty -a

What is the output of this command?

  echo ABC | od -tx1

Bob

Stanislaw Kaminski

2008-Jul-16 09:44 UTC

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EOL in stderr of ssh - Linux

Hi,

Bob wrote:> Stanislaw Kaminski wrote:
>> Correct me if I'm wrong, but I always thought that Linux' EOL
is 0x0A.
>> Imagine my surprise when I saw that all messages that are being output
>> on to the stderr (on any Linux I've tested - Fedora and Ubuntu) are
>> terminated with 0x0D, 0x0A.
>
> What are your tty settings?  What is the output of this command?
>
>  stty -a
>
> What is the output of this command?
>
>  echo ABC | od -tx1
>
>Bob
$ stty -aspeed 38400 baud; rows 44; columns 179; line = 0;
intr = ^C; quit = ^\; erase = ^?; kill = ^U; eof = ^D; eol = <undef>;
eol2 = <undef>; swtch = <undef>; start = ^Q; stop = ^S; susp = ^Z;
rprnt = ^R; werase = ^W; lnext = ^V;
flush = ^O; min = 1; time = 0;
-parenb -parodd cs8 -hupcl -cstopb cread -clocal -crtscts
-ignbrk -brkint -ignpar -parmrk -inpck -istrip -inlcr -igncr icrnl
-ixon -ixoff -iuclc -ixany -imaxbel iutf8
opost -olcuc -ocrnl onlcr -onocr -onlret -ofill -ofdel nl0 cr0 tab0 bs0 vt0 ff0
isig icanon iexten echo echoe echok -echonl -noflsh -xcase -tostop
-echoprt echoctl echoke

$ echo ABC | od -tx1
0000000 41 42 43 0a
0000004

I don't want to post this two times, so I'd like you to read my reply
to Bill's post to see where I see 0x0A 0x0D.

regards,
Stanislaw

Damien Miller

2008-Jul-16 10:09 UTC

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EOL in stderr of ssh - Linux

On Mon, 14 Jul 2008, Stanislaw Kaminski wrote:
> Hello everyone,
> recently I've found something I consider a bug.
> 
> Correct me if I'm wrong, but I always thought that Linux' EOL is
0x0A.
> Imagine my surprise when I saw that all messages that are being output
> on to the stderr (on any Linux I've tested - Fedora and Ubuntu) are
> terminated with 0x0D, 0x0A.
> 
> Maybe that's standard behaviour of all stderr messages in all Linux
> software, but I have to admin it's the first time I saw something like
> this.
> 
> So, can anybody tell me if it's for a purpose, or is it just a plain
bug?
stderr logging is terminated with \r\n in case (IIRC) the terminal is
in raw mode to prevent stair-stepping of text - e.g.

debug1: SSH2_MSG_KEXINIT sent
                             debug1: rekeying in progress
                                                         debug1: rekeying in
progress

... and so forth. I'm not sure why it doesn't appear in the output
earlier -
perhaps cooked terminal mode eats the \r's

The actual code is in log.c.

-d

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