Bug 24399
| Summary: | OpenSSH forced commands munge output | ||
|---|---|---|---|
| Product: | Base System | Reporter: | cjclark <cjclark> |
| Component: | bin | Assignee: | Crist J. Clark <cjc> |
| Status: | Closed FIXED | ||
| Severity: | Affects Only Me | ||
| Priority: | Normal | ||
| Version: | 4.2-STABLE | ||
| Hardware: | Any | ||
| OS: | Any | ||
Responsible Changed From-To: freebsd-bugs->green Over to the maintainer Immediately after submitting this, a workaround did occur to me. I have been using it and it seems to work fine. It is, however, so ugly, so hideous, I considered ROT-13'ing the rest of this mail for the squeamish. I basically put, command="create_output args | uuencode ssh_raw.out" ... In the authorized_keys file on the server, and do a, ssh server | uudecode -p | use_output args At the client end. Since the problem seems to be "\n" -> "\r\n" translation, this works. However, this still needs to be fixed. -- Crist J. Clark cjclark@alum.mit.edu State Changed From-To: open->closed The correct way to handle data being sent through stdout when using forced commands is to add the 'no-pty' specification in the autorized_keys entry for the host. Responsible Changed From-To: green->cjc Closing my own old PR. |
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. 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. 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 $