[Buildroot] [PATCH 1/2] system cfg: default mkpasswd to SHA

[Buildroot] [PATCH 1/2] system cfg: default mkpasswd to SHA

[Matt Weber]

This patch drops the comment about checking the C libraries version as
they now all support it by default
    glibc 2.7+
    uclibc (bdd8362a88 package/uclibc: defconfig: enable sha-256...)
    musl 1.1.14+

This patch updates the help text and changes the default mkpasswd
method to SHA256 from MD5

Cc: Yann E. MORIN <yann.morin.1998@free.fr>
Signed-off-by: Matthew Weber <matthew.weber@rockwellcollins.com>
---
 system/Config.in | 14 +++-----------
 1 file changed, 3 insertions(+), 11 deletions(-)

diff --git a/system/Config.in b/system/Config.in
index 9e34f11..2123d33 100644
--- a/system/Config.in
+++ b/system/Config.in
@@ -61,7 +61,7 @@ endif
 
 choice
 	bool "Passwords encoding"
-	default BR2_TARGET_GENERIC_PASSWD_MD5
+	default BR2_TARGET_GENERIC_PASSWD_SHA256
 	help
 	  Choose the password encoding scheme to use when Buildroot
 	  needs to encode a password (eg. the root password, below).
@@ -81,20 +81,12 @@ config BR2_TARGET_GENERIC_PASSWD_MD5
 config BR2_TARGET_GENERIC_PASSWD_SHA256
 	bool "sha-256"
 	help
-	  Use SHA256 to encode passwords.
-
-	  Very strong, but not ubiquitous, although available in glibc
-	  for some time now. Choose only if you are sure your C library
-	  understands SHA256 passwords.
+	  Use SHA256 to encode passwords which is stronger then MD5.
 
 config BR2_TARGET_GENERIC_PASSWD_SHA512
 	bool "sha-512"
 	help
-	  Use SHA512 to encode passwords.
-
-	  Extremely strong, but not ubiquitous, although available in
-	  glibc for some time now. Choose only if you are sure your C
-	  library understands SHA512 passwords.
+	  Use SHA512 to encode passwords which is stronger then SHA256
 
 endchoice # Passwd encoding
 
-- 
1.9.1

[Buildroot] [PATCH 2/2] system cfg: remove passwd MD5 format

[Matt Weber]

As SHA256 is now default, removing weak MD5 option.  C libraries now
all support the SHA methods.
    glibc 2.7+
    uclibc (bdd8362a88 package/uclibc: defconfig: enable sha-256...)
    musl 1.1.14+

One issue this would prevent is a host tool issue with a FIPS enabled
system where weak ciphers/methods are disabled. The crypt(3) call
checks /proc/sys/crypto/fips_enabled and would result in mkpasswd
returning "crypt failed."  Rather then create a host dependency check
this patch removes the potential issue.

Cc: Yann E. MORIN <yann.morin.1998@free.fr>
Signed-off-by: Matthew Weber <matthew.weber@rockwellcollins.com>
---
 Config.in.legacy |  8 ++++++++
 system/Config.in | 10 ----------
 2 files changed, 8 insertions(+), 10 deletions(-)

diff --git a/Config.in.legacy b/Config.in.legacy
index 02321c8..d70654c 100644
--- a/Config.in.legacy
+++ b/Config.in.legacy
@@ -143,6 +143,14 @@ comment "----------------------------------------------------"
 endif
 
 ###############################################################################
+
+config BR2_TARGET_GENERIC_PASSWD_MD5
+	bool "target passwd md5 format support has been removed"
+	select BR2_LEGACY
+	help
+	  The default has been moved to SHA256 and all C libraries
+	  now support that method by default
+
 comment "Legacy options removed in 2018.11"
 
 config BR2_TARGET_XLOADER
diff --git a/system/Config.in b/system/Config.in
index 2123d33..9a87b1b 100644
--- a/system/Config.in
+++ b/system/Config.in
@@ -68,16 +68,6 @@ choice
 
 	  Note: this is used at build-time, and *not* at runtime.
 
-config BR2_TARGET_GENERIC_PASSWD_MD5
-	bool "md5"
-	help
-	  Use MD5 to encode passwords.
-
-	  The default. Wildly available, and pretty good.
-	  Although pretty strong, MD5 is now an old hash function, and
-	  suffers from some weaknesses, which makes it susceptible to
-	  brute-force attacks.
-
 config BR2_TARGET_GENERIC_PASSWD_SHA256
 	bool "sha-256"
 	help
-- 
1.9.1

[Buildroot] [PATCH 1/2] system cfg: default mkpasswd to SHA

[Yann E. MORIN]

Matt, All,

On 2018-12-05 10:33 -0600, Matt Weber spake thusly:
> This patch drops the comment about checking the C libraries version as
> they now all support it by default
>     glibc 2.7+
>     uclibc (bdd8362a88 package/uclibc: defconfig: enable sha-256...)
>     musl 1.1.14+
> 
> This patch updates the help text and changes the default mkpasswd
> method to SHA256 from MD5

Really, this patch does two things:

  - update my now-wrong comments,

  - switch to using sha256 as the default;

so it should be two patches.

Besides, more comments, below...

> Cc: Yann E. MORIN <yann.morin.1998@free.fr>
> Signed-off-by: Matthew Weber <matthew.weber@rockwellcollins.com>
> ---
>  system/Config.in | 14 +++-----------
>  1 file changed, 3 insertions(+), 11 deletions(-)
> 
> diff --git a/system/Config.in b/system/Config.in
> index 9e34f11..2123d33 100644
> --- a/system/Config.in
> +++ b/system/Config.in
> @@ -61,7 +61,7 @@ endif
>  
>  choice
>  	bool "Passwords encoding"
> -	default BR2_TARGET_GENERIC_PASSWD_MD5
> +	default BR2_TARGET_GENERIC_PASSWD_SHA256
>  	help
>  	  Choose the password encoding scheme to use when Buildroot
>  	  needs to encode a password (eg. the root password, below).
> @@ -81,20 +81,12 @@ config BR2_TARGET_GENERIC_PASSWD_MD5
>  config BR2_TARGET_GENERIC_PASSWD_SHA256
>  	bool "sha-256"
>  	help
> -	  Use SHA256 to encode passwords.
> -
> -	  Very strong, but not ubiquitous, although available in glibc
> -	  for some time now. Choose only if you are sure your C library
> -	  understands SHA256 passwords.
> +	  Use SHA256 to encode passwords which is stronger then MD5.

s/then/than/

>  config BR2_TARGET_GENERIC_PASSWD_SHA512
>  	bool "sha-512"
>  	help
> -	  Use SHA512 to encode passwords.
> -
> -	  Extremely strong, but not ubiquitous, although available in
> -	  glibc for some time now. Choose only if you are sure your C
> -	  library understands SHA512 passwords.
> +	  Use SHA512 to encode passwords which is stronger then SHA256

s/then/than/

With that fix, and the patch split in two, you can add, to each, my:

    Reviewed-by: "Yann E. MORIN" <yann.morin.1998@free.fr>

Regards,
Yann E. MORIN.

>  endchoice # Passwd encoding
>  
> -- 
> 1.9.1
> 

-- 
.-----------------.--------------------.------------------.--------------------.
|  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 2/2] system cfg: remove passwd MD5 format

[Yann E. MORIN]

Matt, All,

On 2018-12-05 10:33 -0600, Matt Weber spake thusly:
> As SHA256 is now default, removing weak MD5 option.  C libraries now
> all support the SHA methods.
>     glibc 2.7+
>     uclibc (bdd8362a88 package/uclibc: defconfig: enable sha-256...)
>     musl 1.1.14+
> 
> One issue this would prevent is a host tool issue with a FIPS enabled
> system where weak ciphers/methods are disabled. The crypt(3) call
> checks /proc/sys/crypto/fips_enabled and would result in mkpasswd
> returning "crypt failed."  Rather then create a host dependency check
> this patch removes the potential issue.
> 
> Cc: Yann E. MORIN <yann.morin.1998@free.fr>
> Signed-off-by: Matthew Weber <matthew.weber@rockwellcollins.com>

Acked-by: "Yann E. MORIN" <yann.morin.1998@free.fr>

Regards,
Yann E. MORIN.

> ---
>  Config.in.legacy |  8 ++++++++
>  system/Config.in | 10 ----------
>  2 files changed, 8 insertions(+), 10 deletions(-)
> 
> diff --git a/Config.in.legacy b/Config.in.legacy
> index 02321c8..d70654c 100644
> --- a/Config.in.legacy
> +++ b/Config.in.legacy
> @@ -143,6 +143,14 @@ comment "----------------------------------------------------"
>  endif
>  
>  ###############################################################################
> +
> +config BR2_TARGET_GENERIC_PASSWD_MD5
> +	bool "target passwd md5 format support has been removed"
> +	select BR2_LEGACY
> +	help
> +	  The default has been moved to SHA256 and all C libraries
> +	  now support that method by default
> +
>  comment "Legacy options removed in 2018.11"
>  
>  config BR2_TARGET_XLOADER
> diff --git a/system/Config.in b/system/Config.in
> index 2123d33..9a87b1b 100644
> --- a/system/Config.in
> +++ b/system/Config.in
> @@ -68,16 +68,6 @@ choice
>  
>  	  Note: this is used at build-time, and *not* at runtime.
>  
> -config BR2_TARGET_GENERIC_PASSWD_MD5
> -	bool "md5"
> -	help
> -	  Use MD5 to encode passwords.
> -
> -	  The default. Wildly available, and pretty good.
> -	  Although pretty strong, MD5 is now an old hash function, and
> -	  suffers from some weaknesses, which makes it susceptible to
> -	  brute-force attacks.
> -
>  config BR2_TARGET_GENERIC_PASSWD_SHA256
>  	bool "sha-256"
>  	help
> -- 
> 1.9.1
> 

-- 
.-----------------.--------------------.------------------.--------------------.
|  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 2/2] system cfg: remove passwd MD5 format

[Matthew Weber]

On Wed, Dec 5, 2018 at 10:33 AM Matt Weber
<matthew.weber@rockwellcollins.com> wrote:
>
> As SHA256 is now default, removing weak MD5 option.  C libraries now
> all support the SHA methods.
>     glibc 2.7+
>     uclibc (bdd8362a88 package/uclibc: defconfig: enable sha-256...)
>     musl 1.1.14+
>
> One issue this would prevent is a host tool issue with a FIPS enabled
> system where weak ciphers/methods are disabled. The crypt(3) call
> checks /proc/sys/crypto/fips_enabled and would result in mkpasswd
> returning "crypt failed."  Rather then create a host dependency check
> this patch removes the potential issue.

A little more research has me changing the reasoning a bit.  This
actually makes more sense.  Our host/bin/mkpasswd uses the host
systems PAM "sufficient algorithm" rules when creating the password.
(https://www.stigviewer.com/stig/red_hat_enterprise_linux_6/2016-06-05/finding/V-38574)
 It just so happens the system we were looking at this issue on was
also configured for other FIPS related desired cipher/hashes.

>
> Cc: Yann E. MORIN <yann.morin.1998@free.fr>
> Signed-off-by: Matthew Weber <matthew.weber@rockwellcollins.com>
> ---
>  Config.in.legacy |  8 ++++++++
>  system/Config.in | 10 ----------
>  2 files changed, 8 insertions(+), 10 deletions(-)
>
> diff --git a/Config.in.legacy b/Config.in.legacy
> index 02321c8..d70654c 100644
> --- a/Config.in.legacy
> +++ b/Config.in.legacy
> @@ -143,6 +143,14 @@ comment "----------------------------------------------------"
>  endif
>
>  ###############################################################################
> +
> +config BR2_TARGET_GENERIC_PASSWD_MD5
> +       bool "target passwd md5 format support has been removed"
> +       select BR2_LEGACY
> +       help
> +         The default has been moved to SHA256 and all C libraries
> +         now support that method by default
> +
>  comment "Legacy options removed in 2018.11"
>
>  config BR2_TARGET_XLOADER
> diff --git a/system/Config.in b/system/Config.in
> index 2123d33..9a87b1b 100644
> --- a/system/Config.in
> +++ b/system/Config.in
> @@ -68,16 +68,6 @@ choice
>
>           Note: this is used at build-time, and *not* at runtime.
>
> -config BR2_TARGET_GENERIC_PASSWD_MD5
> -       bool "md5"
> -       help
> -         Use MD5 to encode passwords.
> -
> -         The default. Wildly available, and pretty good.
> -         Although pretty strong, MD5 is now an old hash function, and
> -         suffers from some weaknesses, which makes it susceptible to
> -         brute-force attacks.
> -
>  config BR2_TARGET_GENERIC_PASSWD_SHA256
>         bool "sha-256"
>         help
> --
> 1.9.1
>


-- 

Matthew Weber | Pr. Software Engineer | Commercial Avionics

COLLINS AEROSPACE

400 Collins Road NE, Cedar Rapids, Iowa 52498, USA

Tel: +1 319 295 7349 | FAX: +1 319 263 6099

matthew.weber at collins.com | collinsaerospace.com



CONFIDENTIALITY WARNING: This message may contain proprietary and/or
privileged information of Collins Aerospace and its affiliated
companies. If you are not the intended recipient, please 1) Do not
disclose, copy, distribute or use this message or its contents. 2)
Advise the sender by return email. 3) Delete all copies (including all
attachments) from your computer. Your cooperation is greatly
appreciated.

[Buildroot] [PATCH 2/2] system cfg: remove passwd MD5 format

[Matthew Weber]

All,

On Wed, Dec 5, 2018 at 7:08 PM Matthew Weber
<matthew.weber@rockwellcollins.com> wrote:
>
> On Wed, Dec 5, 2018 at 10:33 AM Matt Weber
> <matthew.weber@rockwellcollins.com> wrote:
> >
> > As SHA256 is now default, removing weak MD5 option.  C libraries now
> > all support the SHA methods.
> >     glibc 2.7+
> >     uclibc (bdd8362a88 package/uclibc: defconfig: enable sha-256...)
> >     musl 1.1.14+
> >
> > One issue this would prevent is a host tool issue with a FIPS enabled
> > system where weak ciphers/methods are disabled. The crypt(3) call
> > checks /proc/sys/crypto/fips_enabled and would result in mkpasswd
> > returning "crypt failed."  Rather then create a host dependency check
> > this patch removes the potential issue.
>
> A little more research has me changing the reasoning a bit.  This
> actually makes more sense.  Our host/bin/mkpasswd uses the host
> systems PAM "sufficient algorithm" rules when creating the password.
> (https://www.stigviewer.com/stig/red_hat_enterprise_linux_6/2016-06-05/finding/V-38574)
>  It just so happens the system we were looking at this issue on was
> also configured for other FIPS related desired cipher/hashes.

Oops that doesn't seem to be valid for mkpasswd.  just passwd.  I'll
refresh my description when I split the first patch.

>
> >
> > Cc: Yann E. MORIN <yann.morin.1998@free.fr>
> > Signed-off-by: Matthew Weber <matthew.weber@rockwellcollins.com>
> > ---
> >  Config.in.legacy |  8 ++++++++
> >  system/Config.in | 10 ----------
> >  2 files changed, 8 insertions(+), 10 deletions(-)
> >
> > diff --git a/Config.in.legacy b/Config.in.legacy
> > index 02321c8..d70654c 100644
> > --- a/Config.in.legacy
> > +++ b/Config.in.legacy
> > @@ -143,6 +143,14 @@ comment "----------------------------------------------------"
> >  endif
> >
> >  ###############################################################################
> > +
> > +config BR2_TARGET_GENERIC_PASSWD_MD5
> > +       bool "target passwd md5 format support has been removed"
> > +       select BR2_LEGACY
> > +       help
> > +         The default has been moved to SHA256 and all C libraries
> > +         now support that method by default
> > +
> >  comment "Legacy options removed in 2018.11"
> >
> >  config BR2_TARGET_XLOADER
> > diff --git a/system/Config.in b/system/Config.in
> > index 2123d33..9a87b1b 100644
> > --- a/system/Config.in
> > +++ b/system/Config.in
> > @@ -68,16 +68,6 @@ choice
> >
> >           Note: this is used at build-time, and *not* at runtime.
> >
> > -config BR2_TARGET_GENERIC_PASSWD_MD5
> > -       bool "md5"
> > -       help
> > -         Use MD5 to encode passwords.
> > -
> > -         The default. Wildly available, and pretty good.
> > -         Although pretty strong, MD5 is now an old hash function, and
> > -         suffers from some weaknesses, which makes it susceptible to
> > -         brute-force attacks.
> > -
> >  config BR2_TARGET_GENERIC_PASSWD_SHA256
> >         bool "sha-256"
> >         help
> > --
> > 1.9.1
> >
>
>
> --
>
> Matthew Weber | Pr. Software Engineer | Commercial Avionics
>
> COLLINS AEROSPACE
>
> 400 Collins Road NE, Cedar Rapids, Iowa 52498, USA
>
> Tel: +1 319 295 7349 | FAX: +1 319 263 6099
>
> matthew.weber at collins.com | collinsaerospace.com
>
>
>
> CONFIDENTIALITY WARNING: This message may contain proprietary and/or
> privileged information of Collins Aerospace and its affiliated
> companies. If you are not the intended recipient, please 1) Do not
> disclose, copy, distribute or use this message or its contents. 2)
> Advise the sender by return email. 3) Delete all copies (including all
> attachments) from your computer. Your cooperation is greatly
> appreciated.



-- 

Matthew Weber | Pr. Software Engineer | Commercial Avionics

COLLINS AEROSPACE

400 Collins Road NE, Cedar Rapids, Iowa 52498, USA

Tel: +1 319 295 7349 | FAX: +1 319 263 6099

matthew.weber at collins.com | collinsaerospace.com



CONFIDENTIALITY WARNING: This message may contain proprietary and/or
privileged information of Collins Aerospace and its affiliated
companies. If you are not the intended recipient, please 1) Do not
disclose, copy, distribute or use this message or its contents. 2)
Advise the sender by return email. 3) Delete all copies (including all
attachments) from your computer. Your cooperation is greatly
appreciated.