[Buildroot] [PATCH] package/bash: add /bin/bash to /etc/shells

[Buildroot] [PATCH] package/bash: add /bin/bash to /etc/shells

[Romain Naour]

When bash is selected, /bin/bash is not added to /etc/shells
(see man shells). So, login tools like dropbear reject the ssh
connexions for users using bash as shell in /etc/passwd.

buildroot authpriv.warn dropbear[853]: User 'kubu' has invalid shell, rejected

Reported-by: Jeremy Rosen <jeremy.rosen@smile.fr>
Signed-off-by: Romain Naour <romain.naour@smile.fr>
Cc: "Yann E. MORIN" <yann.morin.1998@free.fr>
---
The same issue can happend with other shells.
---
 package/bash/bash.mk | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/package/bash/bash.mk b/package/bash/bash.mk
index 089d062..eec6559 100644
--- a/package/bash/bash.mk
+++ b/package/bash/bash.mk
@@ -40,10 +40,13 @@ endif
 endif
 
 # Make /bin/sh -> bash (no other shell, better than busybox shells)
+# Add /bin/bash to /etc/shells otherwise some login tools like dropbear
+# can reject the user connexion. See man shells.
 define BASH_INSTALL_TARGET_CMDS
 	$(TARGET_MAKE_ENV) $(MAKE) -C $(@D) \
 		DESTDIR=$(TARGET_DIR) exec_prefix=/ install
 	rm -f $(TARGET_DIR)/bin/bashbug
+	echo "/bin/bash" >> $(TARGET_DIR)/etc/shells
 endef
 
 $(eval $(autotools-package))
-- 
2.7.4

[Buildroot] [PATCH] package/bash: add /bin/bash to /etc/shells

[Yann E. MORIN]

Romain, All,

On 2018-01-11 11:27 +0100, Romain Naour spake thusly:
> When bash is selected, /bin/bash is not added to /etc/shells
> (see man shells). So, login tools like dropbear reject the ssh
> connexions for users using bash as shell in /etc/passwd.
> 
> buildroot authpriv.warn dropbear[853]: User 'kubu' has invalid shell, rejected
> 
> Reported-by: Jeremy Rosen <jeremy.rosen@smile.fr>
> Signed-off-by: Romain Naour <romain.naour@smile.fr>
> Cc: "Yann E. MORIN" <yann.morin.1998@free.fr>
> ---
> The same issue can happend with other shells.
> ---
>  package/bash/bash.mk | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/package/bash/bash.mk b/package/bash/bash.mk
> index 089d062..eec6559 100644
> --- a/package/bash/bash.mk
> +++ b/package/bash/bash.mk
> @@ -40,10 +40,13 @@ endif
>  endif
>  
>  # Make /bin/sh -> bash (no other shell, better than busybox shells)
> +# Add /bin/bash to /etc/shells otherwise some login tools like dropbear
> +# can reject the user connexion. See man shells.
>  define BASH_INSTALL_TARGET_CMDS
>  	$(TARGET_MAKE_ENV) $(MAKE) -C $(@D) \
>  		DESTDIR=$(TARGET_DIR) exec_prefix=/ install
>  	rm -f $(TARGET_DIR)/bin/bashbug
> +	echo "/bin/bash" >> $(TARGET_DIR)/etc/shells

What if the user uses a custom skeleton and bash is already listed
there?

I would do:

    grep -E '^/bin/bash$' $(TARGET_DIR)/etc/shells >/dev/null 2>&1 \
    || echo "/bin/bash" >> $(TARGET_DIR)/etc/shells

That way, we only install it if not already present.

Regards,
Yann E. MORIN.

>  endef
>  
>  $(eval $(autotools-package))
> -- 
> 2.7.4
> 

-- 
.-----------------.--------------------.------------------.--------------------.
|  Yann E. MORIN  | Real-Time Embedded | /"\ ASCII RIBBON | Erics' conspiracy: |
| +33 662 376 056 | Software  Designer | \ / CAMPAIGN     |  ___               |
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| http://ymorin.is-a-geek.org/ | _/*\_ | / \ HTML MAIL    |   v   conspiracy.  |
'------------------------------^-------^------------------^--------------------'

[Buildroot] [PATCH] package/bash: add /bin/bash to /etc/shells

[Thomas Petazzoni]

Hello,

On Thu, 11 Jan 2018 18:13:57 +0100, Yann E. MORIN wrote:

> I would do:
> 
>     grep -E '^/bin/bash$' $(TARGET_DIR)/etc/shells >/dev/null 2>&1 \

grep -q ?

>     || echo "/bin/bash" >> $(TARGET_DIR)/etc/shells
> 
> That way, we only install it if not already present.

Otherwise, yes, agreed.

Thomas
-- 
Thomas Petazzoni, CTO, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com

[Buildroot] [PATCH] package/bash: add /bin/bash to /etc/shells

[Romain Naour]

Hi Yann, Thomas,

Le 12/01/2018 ? 09:59, Thomas Petazzoni a ?crit?:
> Hello,
> 
> On Thu, 11 Jan 2018 18:13:57 +0100, Yann E. MORIN wrote:
> 
>> I would do:
>>
>>     grep -E '^/bin/bash$' $(TARGET_DIR)/etc/shells >/dev/null 2>&1 \
> 
> grep -q ?
> 
>>     || echo "/bin/bash" >> $(TARGET_DIR)/etc/shells
>>
>> That way, we only install it if not already present.
> 
> Otherwise, yes, agreed.

Ok, I'll fix this.
But the same issue should happen with other shell (not tested though).

For example, it ash (busybox) is not the default shell and a user use it to
login, it will be rejected.
So busybox should also add /bin/ash in /etc/shells.

Thoughts?

Best regards,
Romain

> 
> Thomas
> 

[Buildroot] [PATCH] package/bash: add /bin/bash to /etc/shells

[Yann E. MORIN]

Thomas, All,

On 2018-01-12 09:59 +0100, Thomas Petazzoni spake thusly:
> On Thu, 11 Jan 2018 18:13:57 +0100, Yann E. MORIN wrote:
> >     grep -E '^/bin/bash$' $(TARGET_DIR)/etc/shells >/dev/null 2>&1 \
> grep -q ?

-q is not POSIX. Redirecting is guaranteed to always work.

Regards,
Yann E. MORIN.

-- 
.-----------------.--------------------.------------------.--------------------.
|  Yann E. MORIN  | Real-Time Embedded | /"\ ASCII RIBBON | Erics' conspiracy: |
| +33 662 376 056 | Software  Designer | \ / CAMPAIGN     |  ___               |
| +33 223 225 172 `------------.-------:  X  AGAINST      |  \e/  There is no  |
| http://ymorin.is-a-geek.org/ | _/*\_ | / \ HTML MAIL    |   v   conspiracy.  |
'------------------------------^-------^------------------^--------------------'

[Buildroot] [PATCH] package/bash: add /bin/bash to /etc/shells

[Yann E. MORIN]

Romain, All,

On 2018-01-12 10:06 +0100, Romain Naour spake thusly:
> Le 12/01/2018 ? 09:59, Thomas Petazzoni a ?crit?:
> > On Thu, 11 Jan 2018 18:13:57 +0100, Yann E. MORIN wrote:
> >> I would do:
> >>     grep -E '^/bin/bash$' $(TARGET_DIR)/etc/shells >/dev/null 2>&1 \
> Ok, I'll fix this.
> But the same issue should happen with other shell (not tested though).

You are fixing bash with thispatch. Other patches could fix the other
shells. ;-)

Regards,
Yann E. MORIN.

-- 
.-----------------.--------------------.------------------.--------------------.
|  Yann E. MORIN  | Real-Time Embedded | /"\ ASCII RIBBON | Erics' conspiracy: |
| +33 662 376 056 | Software  Designer | \ / CAMPAIGN     |  ___               |
| +33 223 225 172 `------------.-------:  X  AGAINST      |  \e/  There is no  |
| http://ymorin.is-a-geek.org/ | _/*\_ | / \ HTML MAIL    |   v   conspiracy.  |
'------------------------------^-------^------------------^--------------------'

[Buildroot] [PATCH] package/bash: add /bin/bash to /etc/shells

[Thomas Petazzoni]

Hello,

On Fri, 12 Jan 2018 18:35:10 +0100, Yann E. MORIN wrote:

> On 2018-01-12 09:59 +0100, Thomas Petazzoni spake thusly:
> > On Thu, 11 Jan 2018 18:13:57 +0100, Yann E. MORIN wrote:  
> > >     grep -E '^/bin/bash$' $(TARGET_DIR)/etc/shells >/dev/null 2>&1 \  
> > grep -q ?  
> 
> -q is not POSIX. Redirecting is guaranteed to always work.

Knowing that Buildroot only supports Linux hosts, do we care about -q
not being POSIX ?

Thomas
-- 
Thomas Petazzoni, CTO, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com

[Buildroot] [PATCH] package/bash: add /bin/bash to /etc/shells

[Yann E. MORIN]

Thomas, All,

On 2018-01-12 21:21 +0100, Thomas Petazzoni spake thusly:
> On Fri, 12 Jan 2018 18:35:10 +0100, Yann E. MORIN wrote:
> > On 2018-01-12 09:59 +0100, Thomas Petazzoni spake thusly:
> > > On Thu, 11 Jan 2018 18:13:57 +0100, Yann E. MORIN wrote:  
> > > >     grep -E '^/bin/bash$' $(TARGET_DIR)/etc/shells >/dev/null 2>&1 \  
> > > grep -q ?  
> > 
> > -q is not POSIX. Redirecting is guaranteed to always work.
> 
> Knowing that Buildroot only supports Linux hosts, do we care about -q
> not being POSIX ?

Linux host does not mean GNU extensions. For example, Alpine is using
busybox, so not GNU grep...

But I back-pedal on this, it seems that -q has been added to POSIX now:
    http://pubs.opengroup.org/onlinepubs/9699919799/utilities/grep.html

Regards,
Yann E. MORIN.

-- 
.-----------------.--------------------.------------------.--------------------.
|  Yann E. MORIN  | Real-Time Embedded | /"\ ASCII RIBBON | Erics' conspiracy: |
| +33 662 376 056 | Software  Designer | \ / CAMPAIGN     |  ___               |
| +33 223 225 172 `------------.-------:  X  AGAINST      |  \e/  There is no  |
| http://ymorin.is-a-geek.org/ | _/*\_ | / \ HTML MAIL    |   v   conspiracy.  |
'------------------------------^-------^------------------^--------------------'

[Buildroot] [PATCH] package/bash: add /bin/bash to /etc/shells

[Peter Korsgaard]

>>>>> "Yann" == Yann E MORIN <yann.morin.1998@free.fr> writes:

 > Thomas, All,
 > On 2018-01-12 21:21 +0100, Thomas Petazzoni spake thusly:
 >> On Fri, 12 Jan 2018 18:35:10 +0100, Yann E. MORIN wrote:
 >> > On 2018-01-12 09:59 +0100, Thomas Petazzoni spake thusly:
 >> > > On Thu, 11 Jan 2018 18:13:57 +0100, Yann E. MORIN wrote:  
 >> > > >     grep -E '^/bin/bash$' $(TARGET_DIR)/etc/shells >/dev/null 2>&1 \  
 >> > > grep -q ?  
 >> > 
 >> > -q is not POSIX. Redirecting is guaranteed to always work.
 >> 
 >> Knowing that Buildroot only supports Linux hosts, do we care about -q
 >> not being POSIX ?

 > Linux host does not mean GNU extensions. For example, Alpine is using
 > busybox, so not GNU grep...

 > But I back-pedal on this, it seems that -q has been added to POSIX now:
 >     http://pubs.opengroup.org/onlinepubs/9699919799/utilities/grep.html

And busybox grep DOES support -q.

-- 
Bye, Peter Korsgaard