Date: Tue, 16 Jan 2001 23:37:07 -0800 (PST) From: cjclark@reflexcom.com To: FreeBSD-gnats-submit@freebsd.org Subject: bin/24399: OpenSSH forced commands munge output Message-ID: <200101170737.f0H7b7t60224@rfx-64-6-211-149.users.reflexcom.com>
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>Number: 24399
>Category: bin
>Synopsis: OpenSSH forced commands munge output
>Confidential: no
>Severity: serious
>Priority: high
>Responsible: freebsd-bugs
>State: open
>Quarter:
>Keywords:
>Date-Required:
>Class: sw-bug
>Submitter-Id: current-users
>Arrival-Date: Tue Jan 16 23:40:01 PST 2001
>Closed-Date:
>Last-Modified:
>Originator: Crist J. Clark
>Release: FreeBSD 4.2-STABLE i386
>Organization:
>Environment:
FreeBSD 4.2-STABLE
SSH Version OpenSSH_2.2.0, protocol versions 1.5/2.0.
Compiled with SSL (0x0090600f).
>Description:
OpenSSH "forced commands," a command specified in the
authorized_keys file, have their output mangled. It looks like
their is some UNIX-MSDOS conversion going on. Newlines, \n,
are substituted with \r\n.
>How-To-Repeat:
Assuming you have sshd running locally and don't have
anything in your configs to break this kind of thing.
$ man ssh > ssh_1.cat
$ ssh-keygen -f sshtest -N "" -C SSH-Test
$ { echo 'command="cat ssh_1.cat" '; cat sshtest.pub; } >> .ssh/authorized_keys
$ ssh -i sshtest localhost > ssh_2.cat
$ cmp ssh_1.cat ssh_2.cat
ssh_1.cat ssh_2.cat differ: char 79, line 1
$ tr -d '\r' < ssh_2.cat > ssh_3.cat
$ cmp ssh_1.cat ssh_3.cat
$
But this works,
$ ssh localhost "cat ssh_1.cat" > ssh_4.cat
cjc@localhost's password:
$ cmp ssh_1.cat ssh_4.cat
$
>Fix:
No workaround other than to not use forced commands.
After a quick look at the code, I can't see how a "forced
command" would produce different results than one provided on
the command line. But that's what the tests show.
>Release-Note:
>Audit-Trail:
>Unformatted:
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