Por que a opção '-e' está ausente no netcat-openbsd?

13

Por que a -eopção está faltando no netcat-openbsdpacote? Existe um netcat-traditionalpacote, mas há muitos recursos ausentes no pacote OpenBSD. Estou executando o Linux Mint 16.

Alguém sabe por que isso está faltando? Ele remove um grande recurso do netcat.

p1xel
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possível duplicata de versões do netcat
Ciro Santilli冠状病毒审查六四事件法轮功

Respostas:

17

Porque existem várias versões do programa.

Não existe um "padrão" que descreva quais opções netcatdevem ser suportadas, ao contrário de muitos outros utilitários padrão especificados no POSIX. Você tem netcatversões do OpenBSD, FreeBSD, GNU netcat , etc.

Para a variante do OpenBSD, a página de manual observa que :

There is no -c or -e option in this netcat, but you still can execute a
 command after connection being established by redirecting file descriptors.
 Be cautious here because opening a port and let anyone connected execute
 arbitrary command on your site is DANGEROUS. If you really need to do this,
 here is an example:

 On ‘server’ side:

       $ rm -f /tmp/f; mkfifo /tmp/f
       $ cat /tmp/f | /bin/sh -i 2>&1 | nc -l 127.0.0.1 1234 > /tmp/f

 On ‘client’ side:

       $ nc host.example.com 1234
       $ (shell prompt from host.example.com)

 By doing this, you create a fifo at /tmp/f and make nc listen at port 1234
 of address 127.0.0.1 on ‘server’ side, when a ‘client’ establishes a
 connection successfully to that port, /bin/sh gets executed on ‘server’
 side and the shell prompt is given to ‘client’ side.

 When connection is terminated, nc quits as well. Use -k if you want it keep
 listening, but if the command quits this option won't restart it or keep nc
 running. Also don't forget to remove the file descriptor once you don't
 need it anymore:

       $ rm -f /tmp/f
slhck
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