Fwd: Crashing the Linux System

[LitHack]

-- Forwarded message -
From: LitHack 
Date: Sat, 17 Jun 2023 at 08:52
Subject: Crashing the Linux System
To: 


Running the yes command in command substitution will crash the linux shell.
According to me inside command the substitution it is creating multiple
process(fork).  Command: `yes` or $(yes)

Here is the bug report:
Bug report <https://bugzilla.kernel.org/show_bug.cgi?id=217565>

Fwd: Command execution by creating file.

[LitHack]

-- Forwarded message -
From: LitHack 
Date: Wed, Jun 21, 2023, 7:31 AM
Subject: Command execution by creating file.
To: 


Special character '*' can be used to execute the command.
We have to just create a directory and make a file of any character or word
and then make alias of the command which we want to execute assigned with
created file. Now just type the * in terminal and you will that the command
be executed.
But why this happens, * (special character) is used for auto completion and
if used as alone it should just print the name of file why it's execute the
file name as command.
Command:mkdir dir;cd dir:<>file;alias file=ls -l;*

Re: Fwd: Command execution by creating file.

[LitHack]

Sorry instead of alias we have to use the function.

Corrected command: mkdir dir;cd dir;<>file;file()bash;*

Thanks and regards.

On Wed, Jun 21, 2023, 8:46 AM Lawrence Velázquez  wrote:

> On Tue, Jun 20, 2023, at 10:52 PM, LitHack wrote:
> > -- Forwarded message -
> > From: LitHack 
> > Date: Wed, Jun 21, 2023, 7:31 AM
> > Subject: Command execution by creating file.
> > To: 
> >
> >
> > Special character '*' can be used to execute the command.
> > We have to just create a directory and make a file of any character or
> word
> > and then make alias of the command which we want to execute assigned with
> > created file. Now just type the * in terminal and you will that the
> command
> > be executed.
>
> This is not true.  Alias expansion occurs before filename expansion.
>
> > But why this happens, * (special character) is used for auto completion
> and
> > if used as alone it should just print the name of file why it's execute
> the
> > file name as command.
>
> This is not true either.  What makes you think that it should "just
> print the name of file"?
>
> > Command:mkdir dir;cd dir:<>file;alias file=ls -l;*
>
> Did you actually run these commands?  They don't agree with you.
>
> bash-5.2$ mkdir dir
> bash-5.2$ cd dir
> bash-5.2$ <> file
> bash-5.2$ alias file='ls -l'
> bash-5.2$ *
> Usage: file [bcCdEhikLlNnprsvzZ0] [-e test] [-f namefile] [-F
> separator] [-m magicfiles] [-M magicfiles] file...
>file -C -m magicfiles
> Try `file --help' for more information.
>
> --
> vq
>

Alias in command substitution

[LitHack]

Normally declaring a alias inside the command substitution would not
reflect in main shell like
lithack@aura:~$ `alias l=ls`
lithack@aura:~$ l
l: command not found
But using this command .
lithack@aura:~$ `alias l=ls;alias`
lithack@aura:~$ l
 api  Desktop  Downloads  Music __py__  v  v.zip
 Arjun  dir  idafree82_linux.run  Pictures snap vi
 BurpSuiteCommunity   Documents  'IDA Freeware 8.2.desktop'   Public
Templates   Videos
It runs in main shell. Is this a bug?

Note: This only works in bash shell.