[Zsh bug] function define bug

[Zsh bug] function define bug

[Ngô Huy]

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Dear folks,

I found the problem in zsh define function. Demo

ls test() { echo "Bug !!!"} && ls && test

it will print

Bug !!!
Bug !!!

We should patch this behavior or it will break user case without quote
string. Workaround is always quoted strings after commands.

Kind regards,
Severus

Re: [Zsh bug] function define bug

[Matthew Martin]

On Tue, Nov 24, 2015 at 9:46 PM, Ngô Huy <huynhok.uit@vnoss.org> wrote:
> Dear folks,
>
> I found the problem in zsh define function. Demo
>
> ls test() { echo "Bug !!!"} && ls && test
>
> it will print
>
> Bug !!!
> Bug !!!


That's expected behaviour. Since MULTI_FUNC_DEF is set by default in zsh
mode, both ls and test are being defined as functions with the body
echo "Bug !!!".

% func1 func2 () { echo This is "$0"; }
% func1; func2
This is func1
This is func2
% which func{1,2}
func1 () {
        echo This is "$0"
}
func2 () {
        echo This is "$0"
}
% unsetopt MULTI_FUNC_DEF
% func1 func2 () { echo This is "$0"; }
zsh: parse error near `()'

Re: [Zsh bug] function define bug

[Ngô Huy]

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Dear Matthew

2015-11-25 11:06 GMT+07:00 Matthew Martin <phy1729@gmail.com>:

> On Tue, Nov 24, 2015 at 9:46 PM, Ngô Huy <huynhok.uit@vnoss.org> wrote:
> > Dear folks,
> >
> > I found the problem in zsh define function. Demo
> >
> > ls test() { echo "Bug !!!"} && ls && test
> >
> > it will print
> >
> > Bug !!!
> > Bug !!!
>
>
> That's expected behaviour. Since MULTI_FUNC_DEF is set by default in zsh
> mode, both ls and test are being defined as functions with the body
> echo "Bug !!!".
>
> % func1 func2 () { echo This is "$0"; }
> % func1; func2
> This is func1
> This is func2
> % which func{1,2}
> func1 () {
>         echo This is "$0"
> }
> func2 () {
>         echo This is "$0"
> }
> % unsetopt MULTI_FUNC_DEF
> % func1 func2 () { echo This is "$0"; }
> zsh: parse error near `()'
>

I know this behavior likes advanced programming language but multì_func_def
should be turned off by default, it leads to risky problem when someone
searchs as grep, ls malicious strings without quote


Kind regards,
Severus

Re: [Zsh bug] function define bug

[Cuong Manh Le]

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Hi Severus,

Can you give a demo?

You can turn off `multì_func_def` but you can always do multiple function
definition with reserved word `function`

Best.

On Wed, Nov 25, 2015 at 11:20 AM, Ngô Huy <huynhok.uit@vnoss.org> wrote:

> Dear Matthew
>
> 2015-11-25 11:06 GMT+07:00 Matthew Martin <phy1729@gmail.com>:
>
> > On Tue, Nov 24, 2015 at 9:46 PM, Ngô Huy <huynhok.uit@vnoss.org> wrote:
> > > Dear folks,
> > >
> > > I found the problem in zsh define function. Demo
> > >
> > > ls test() { echo "Bug !!!"} && ls && test
> > >
> > > it will print
> > >
> > > Bug !!!
> > > Bug !!!
> >
> >
> > That's expected behaviour. Since MULTI_FUNC_DEF is set by default in zsh
> > mode, both ls and test are being defined as functions with the body
> > echo "Bug !!!".
> >
> > % func1 func2 () { echo This is "$0"; }
> > % func1; func2
> > This is func1
> > This is func2
> > % which func{1,2}
> > func1 () {
> >         echo This is "$0"
> > }
> > func2 () {
> >         echo This is "$0"
> > }
> > % unsetopt MULTI_FUNC_DEF
> > % func1 func2 () { echo This is "$0"; }
> > zsh: parse error near `()'
> >
>
> I know this behavior likes advanced programming language but multì_func_def
> should be turned off by default, it leads to risky problem when someone
> searchs as grep, ls malicious strings without quote
>
>
> Kind regards,
> Severus
>

Re: [Zsh bug] function define bug

[Ngô Huy]

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Dear Cuong,

2015-11-25 15:49 GMT+07:00 Cuong Manh Le <cuong.manhle.vn@gmail.com>:

> Hi Severus,
>
> Can you give a demo?
>
> You can turn off `multì_func_def` but you can always do multiple function
> definition with reserved word `function`
>
> Best.
>
>
> On Wed, Nov 25, 2015 at 11:20 AM, Ngô Huy <huynhok.uit@vnoss.org> wrote:
>
>> Dear Matthew
>>
>> 2015-11-25 11:06 GMT+07:00 Matthew Martin <phy1729@gmail.com>:
>>
>> > On Tue, Nov 24, 2015 at 9:46 PM, Ngô Huy <huynhok.uit@vnoss.org> wrote:
>> > > Dear folks,
>> > >
>> > > I found the problem in zsh define function. Demo
>> > >
>> > > ls test() { echo "Bug !!!"} && ls && test
>> > >
>> > > it will print
>> > >
>> > > Bug !!!
>> > > Bug !!!
>> >
>> >
>> > That's expected behaviour. Since MULTI_FUNC_DEF is set by default in zsh
>> > mode, both ls and test are being defined as functions with the body
>> > echo "Bug !!!".
>> >
>> > % func1 func2 () { echo This is "$0"; }
>> > % func1; func2
>> > This is func1
>> > This is func2
>> > % which func{1,2}
>> > func1 () {
>> >         echo This is "$0"
>> > }
>> > func2 () {
>> >         echo This is "$0"
>> > }
>> > % unsetopt MULTI_FUNC_DEF
>> > % func1 func2 () { echo This is "$0"; }
>> > zsh: parse error near `()'
>> >
>>
>> I know this behavior likes advanced programming language but
>> multì_func_def
>> should be turned off by default, it leads to risky problem when someone
>> searchs as grep, ls malicious strings without quote
>>
>>
>> Kind regards,
>> Severus
>>
>
> this's just example: cat file | grep foobar(){ rm -rf *}
grep wil execute rest of body

Kind regards,
Severus

Re: [Zsh bug] function define bug

[Ngô Huy]

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Dear all,


2015-11-25 16:03 GMT+07:00 Ngô Huy <huynhok.uit@vnoss.org>:

> Dear Cuong,
>
> 2015-11-25 15:49 GMT+07:00 Cuong Manh Le <cuong.manhle.vn@gmail.com>:
>
>> Hi Severus,
>>
>> Can you give a demo?
>>
>> You can turn off `multì_func_def` but you can always do multiple function
>> definition with reserved word `function`
>>
>> Best.
>>
>>
>> On Wed, Nov 25, 2015 at 11:20 AM, Ngô Huy <huynhok.uit@vnoss.org> wrote:
>>
>>> Dear Matthew
>>>
>>> 2015-11-25 11:06 GMT+07:00 Matthew Martin <phy1729@gmail.com>:
>>>
>>> > On Tue, Nov 24, 2015 at 9:46 PM, Ngô Huy <huynhok.uit@vnoss.org>
>>> wrote:
>>> > > Dear folks,
>>> > >
>>> > > I found the problem in zsh define function. Demo
>>> > >
>>> > > ls test() { echo "Bug !!!"} && ls && test
>>> > >
>>> > > it will print
>>> > >
>>> > > Bug !!!
>>> > > Bug !!!
>>> >
>>> >
>>> > That's expected behaviour. Since MULTI_FUNC_DEF is set by default in
>>> zsh
>>> > mode, both ls and test are being defined as functions with the body
>>> > echo "Bug !!!".
>>> >
>>> > % func1 func2 () { echo This is "$0"; }
>>> > % func1; func2
>>> > This is func1
>>> > This is func2
>>> > % which func{1,2}
>>> > func1 () {
>>> >         echo This is "$0"
>>> > }
>>> > func2 () {
>>> >         echo This is "$0"
>>> > }
>>> > % unsetopt MULTI_FUNC_DEF
>>> > % func1 func2 () { echo This is "$0"; }
>>> > zsh: parse error near `()'
>>> >
>>>
>>> I know this behavior likes advanced programming language but
>>> multì_func_def
>>> should be turned off by default, it leads to risky problem when someone
>>> searchs as grep, ls malicious strings without quote
>>>
>>>
>>> Kind regards,
>>> Severus
>>>
>>
>> this's just example: cat file | grep foobar(){ rm -rf *}
> grep wil execute rest of body
>
> Kind regards,
> Severus
>
I don't see reason for multiple functions have same body but different
name. Let's me know if I'm wrong :)

Kind regards,
Severus

Re: [Zsh bug] function define bug

[Christoph (Stucki) von Stuckrad]

On Wed, 25 Nov 2015, Ngô Huy wrote:

> I don't see reason for multiple functions have same body but different
> name. Let's me know if I'm wrong :)

There are some programs, which do different things, if called by
different names (mostly links or symlinks to the same binary).

So to 'wrap' such a beast you'd need to wrap lost of names to
the same function, which inside it would call something like
{ command $0 "$@" }

This is the only case I ever used somethng like
lots of different names at onece real_name() {
        wrapper contents
}
to define all the things at once.

Stucki

-- 
Christoph von Stuckrad      * * |nickname |Mail <stucki@mi.fu-berlin.de> \
Freie Universitaet Berlin   |/_*|'stucki' |Tel(Mo.,Mi.):+49 30 838-75 459|
Mathematik & Informatik EDV |\ *|if online|  (Di,Do,Fr):+49 30 77 39 6600|
Takustr. 9 / 14195 Berlin   * * |on IRCnet|Fax(home):   +49 30 77 39 6601/

Re: [Zsh bug] function define bug

[Cuong Manh Le]

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Hi Huy,

It's a good point, but in the user perspective, turn off `multifuncdef` is
not much useful:

$ unsetopt multifuncdef
$ echo 1 | grep foobar(){ echo 1; }
zsh: parse error near `()'

You still stuck and can not use `grep`.

The right way to use it from the beginning is quote the grep string pattern
if it contains any shell meta characters.

Also in zsh documentation
http://zsh.sourceforge.net/Doc/Release/Options.html#index-MULTIFUNCDEF , it
said that:

Multiple function definitions are not often used and can cause obscure
> errors.


Maybe we should add an example to that section.

Best.



On Wed, Nov 25, 2015 at 4:03 PM, Ngô Huy <huynhok.uit@vnoss.org> wrote:

> Dear Cuong,
>
> 2015-11-25 15:49 GMT+07:00 Cuong Manh Le <cuong.manhle.vn@gmail.com>:
>
>> Hi Severus,
>>
>> Can you give a demo?
>>
>> You can turn off `multì_func_def` but you can always do multiple function
>> definition with reserved word `function`
>>
>> Best.
>>
>>
>> On Wed, Nov 25, 2015 at 11:20 AM, Ngô Huy <huynhok.uit@vnoss.org> wrote:
>>
>>> Dear Matthew
>>>
>>> 2015-11-25 11:06 GMT+07:00 Matthew Martin <phy1729@gmail.com>:
>>>
>>> > On Tue, Nov 24, 2015 at 9:46 PM, Ngô Huy <huynhok.uit@vnoss.org>
>>> wrote:
>>> > > Dear folks,
>>> > >
>>> > > I found the problem in zsh define function. Demo
>>> > >
>>> > > ls test() { echo "Bug !!!"} && ls && test
>>> > >
>>> > > it will print
>>> > >
>>> > > Bug !!!
>>> > > Bug !!!
>>> >
>>> >
>>> > That's expected behaviour. Since MULTI_FUNC_DEF is set by default in
>>> zsh
>>> > mode, both ls and test are being defined as functions with the body
>>> > echo "Bug !!!".
>>> >
>>> > % func1 func2 () { echo This is "$0"; }
>>> > % func1; func2
>>> > This is func1
>>> > This is func2
>>> > % which func{1,2}
>>> > func1 () {
>>> >         echo This is "$0"
>>> > }
>>> > func2 () {
>>> >         echo This is "$0"
>>> > }
>>> > % unsetopt MULTI_FUNC_DEF
>>> > % func1 func2 () { echo This is "$0"; }
>>> > zsh: parse error near `()'
>>> >
>>>
>>> I know this behavior likes advanced programming language but
>>> multì_func_def
>>> should be turned off by default, it leads to risky problem when someone
>>> searchs as grep, ls malicious strings without quote
>>>
>>>
>>> Kind regards,
>>> Severus
>>>
>>
>> this's just example: cat file | grep foobar(){ rm -rf *}
> grep wil execute rest of body
>
> Kind regards,
> Severus
>

Re: [Zsh bug] function define bug

[Ngô Huy]

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Dear Cuong,

2015-11-25 16:20 GMT+07:00 Cuong Manh Le <cuong.manhle.vn@gmail.com>:

> Hi Huy,
>
> It's a good point, but in the user perspective, turn off `multifuncdef` is
> not much useful:
>
> $ unsetopt multifuncdef
> $ echo 1 | grep foobar(){ echo 1; }
> zsh: parse error near `()'
>
> You still stuck and can not use `grep`.
>
> The right way to use it from the beginning is quote the grep string
> pattern if it contains any shell meta characters.
>
> Also in zsh documentation
> http://zsh.sourceforge.net/Doc/Release/Options.html#index-MULTIFUNCDEF ,
> it said that:
>
> Multiple function definitions are not often used and can cause obscure
>> errors.
>
>
> Maybe we should add an example to that section.
>
> Best.
>
>
>
> On Wed, Nov 25, 2015 at 4:03 PM, Ngô Huy <huynhok.uit@vnoss.org> wrote:
>
>> Dear Cuong,
>>
>> 2015-11-25 15:49 GMT+07:00 Cuong Manh Le <cuong.manhle.vn@gmail.com>:
>>
>>> Hi Severus,
>>>
>>> Can you give a demo?
>>>
>>> You can turn off `multì_func_def` but you can always do multiple
>>> function definition with reserved word `function`
>>>
>>> Best.
>>>
>>>
>>> On Wed, Nov 25, 2015 at 11:20 AM, Ngô Huy <huynhok.uit@vnoss.org> wrote:
>>>
>>>> Dear Matthew
>>>>
>>>> 2015-11-25 11:06 GMT+07:00 Matthew Martin <phy1729@gmail.com>:
>>>>
>>>> > On Tue, Nov 24, 2015 at 9:46 PM, Ngô Huy <huynhok.uit@vnoss.org>
>>>> wrote:
>>>> > > Dear folks,
>>>> > >
>>>> > > I found the problem in zsh define function. Demo
>>>> > >
>>>> > > ls test() { echo "Bug !!!"} && ls && test
>>>> > >
>>>> > > it will print
>>>> > >
>>>> > > Bug !!!
>>>> > > Bug !!!
>>>> >
>>>> >
>>>> > That's expected behaviour. Since MULTI_FUNC_DEF is set by default in
>>>> zsh
>>>> > mode, both ls and test are being defined as functions with the body
>>>> > echo "Bug !!!".
>>>> >
>>>> > % func1 func2 () { echo This is "$0"; }
>>>> > % func1; func2
>>>> > This is func1
>>>> > This is func2
>>>> > % which func{1,2}
>>>> > func1 () {
>>>> >         echo This is "$0"
>>>> > }
>>>> > func2 () {
>>>> >         echo This is "$0"
>>>> > }
>>>> > % unsetopt MULTI_FUNC_DEF
>>>> > % func1 func2 () { echo This is "$0"; }
>>>> > zsh: parse error near `()'
>>>> >
>>>>
>>>> I know this behavior likes advanced programming language but
>>>> multì_func_def
>>>> should be turned off by default, it leads to risky problem when someone
>>>> searchs as grep, ls malicious strings without quote
>>>>
>>>>
>>>> Kind regards,
>>>> Severus
>>>>
>>>
>>> this's just example: cat file | grep foobar(){ rm -rf *}
>> grep wil execute rest of body
>>
>> Kind regards,
>> Severus
>>
>
> I don't see any case we should use multiple function definition. We also
can not cover all problems with this behavior. I think we should disable it
:)

Kind regards,
Severus

Re: [Zsh bug] function define bug

[Cuong Manh Le]

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Hi Huy,

See this commit
https://github.com/zsh-users/zsh/commit/b4a198cdda3d499af4e2b4f4a2279f98c8d07433
for an example usage.

Best.

On Wed, Nov 25, 2015 at 4:39 PM, Ngô Huy <huynhok.uit@vnoss.org> wrote:

> Dear Cuong,
>
> 2015-11-25 16:20 GMT+07:00 Cuong Manh Le <cuong.manhle.vn@gmail.com>:
>
>> Hi Huy,
>>
>> It's a good point, but in the user perspective, turn off `multifuncdef`
>> is not much useful:
>>
>> $ unsetopt multifuncdef
>> $ echo 1 | grep foobar(){ echo 1; }
>> zsh: parse error near `()'
>>
>> You still stuck and can not use `grep`.
>>
>> The right way to use it from the beginning is quote the grep string
>> pattern if it contains any shell meta characters.
>>
>> Also in zsh documentation
>> http://zsh.sourceforge.net/Doc/Release/Options.html#index-MULTIFUNCDEF ,
>> it said that:
>>
>> Multiple function definitions are not often used and can cause obscure
>>> errors.
>>
>>
>> Maybe we should add an example to that section.
>>
>> Best.
>>
>>
>>
>> On Wed, Nov 25, 2015 at 4:03 PM, Ngô Huy <huynhok.uit@vnoss.org> wrote:
>>
>>> Dear Cuong,
>>>
>>> 2015-11-25 15:49 GMT+07:00 Cuong Manh Le <cuong.manhle.vn@gmail.com>:
>>>
>>>> Hi Severus,
>>>>
>>>> Can you give a demo?
>>>>
>>>> You can turn off `multì_func_def` but you can always do multiple
>>>> function definition with reserved word `function`
>>>>
>>>> Best.
>>>>
>>>>
>>>> On Wed, Nov 25, 2015 at 11:20 AM, Ngô Huy <huynhok.uit@vnoss.org>
>>>> wrote:
>>>>
>>>>> Dear Matthew
>>>>>
>>>>> 2015-11-25 11:06 GMT+07:00 Matthew Martin <phy1729@gmail.com>:
>>>>>
>>>>> > On Tue, Nov 24, 2015 at 9:46 PM, Ngô Huy <huynhok.uit@vnoss.org>
>>>>> wrote:
>>>>> > > Dear folks,
>>>>> > >
>>>>> > > I found the problem in zsh define function. Demo
>>>>> > >
>>>>> > > ls test() { echo "Bug !!!"} && ls && test
>>>>> > >
>>>>> > > it will print
>>>>> > >
>>>>> > > Bug !!!
>>>>> > > Bug !!!
>>>>> >
>>>>> >
>>>>> > That's expected behaviour. Since MULTI_FUNC_DEF is set by default in
>>>>> zsh
>>>>> > mode, both ls and test are being defined as functions with the body
>>>>> > echo "Bug !!!".
>>>>> >
>>>>> > % func1 func2 () { echo This is "$0"; }
>>>>> > % func1; func2
>>>>> > This is func1
>>>>> > This is func2
>>>>> > % which func{1,2}
>>>>> > func1 () {
>>>>> >         echo This is "$0"
>>>>> > }
>>>>> > func2 () {
>>>>> >         echo This is "$0"
>>>>> > }
>>>>> > % unsetopt MULTI_FUNC_DEF
>>>>> > % func1 func2 () { echo This is "$0"; }
>>>>> > zsh: parse error near `()'
>>>>> >
>>>>>
>>>>> I know this behavior likes advanced programming language but
>>>>> multì_func_def
>>>>> should be turned off by default, it leads to risky problem when someone
>>>>> searchs as grep, ls malicious strings without quote
>>>>>
>>>>>
>>>>> Kind regards,
>>>>> Severus
>>>>>
>>>>
>>>> this's just example: cat file | grep foobar(){ rm -rf *}
>>> grep wil execute rest of body
>>>
>>> Kind regards,
>>> Severus
>>>
>>
>> I don't see any case we should use multiple function definition. We also
> can not cover all problems with this behavior. I think we should disable it
> :)
>
> Kind regards,
> Severus
>

Re: [Zsh bug] function define bug

[Peter Stephenson]

The MULTI_FUNC_DEF behaviour was there in the shell from the start (and
didn't used to be optional) --- I think it was there mostly for defining
multiple trap functions in one go.  That's about the only standard use,
anyway (there was one instance in the completion code until we removed
it).

Feel absolutely free to turn it otf yourself, but please can we stop the
yes we should / no we shouldn't unless you have new information.

Thanks
pws

Re: [Zsh bug] function define bug

[Ngô Huy]

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Thanks Peter,

I see :)