[OE-core] [PATCH] busybox.inc: Add sanity check to test if the suid binary provides sh

[Andrej Valek]

Of course, I don't think so, that /bin/sh > /bin/busybox.suid is a good
think. I am just thinking, why is necessary to cast a fatal message and
stop build for some, who wants this.

Andrej

On 11/10/2017 12:57 PM, Burton, Ross wrote:
> How is /bin/sh being busybox.suid a good thing?
> 
> Ross
> 
> On 10 November 2017 at 07:17, Andrej Valek <andrej.valek at siemens.com 
> <mailto:andrej.valek at siemens.com>> wrote:
> 
>     I don't think so, that adding bbfatal into this recipe is a good
>     solution. Someone could build the busybox with /bin/sh linking into
>     .suid eg. for more secure. We can leave live with this one as before.
> 
>     Andrej
> 
>     On 11/09/2017 02:25 PM, Nathan Rossi wrote:
>      > Add a sanity check during the do_compile task to fail if the suid
>      > busybox provides /bin/sh. This is considered as a hard fail since not
>      > only is providing sh as suid problematic for security reasons but also
>      > because the sh configured for suid is less functional than the nosuid
>      > configured sh and breaks a number of required features (e.g. 64-bit
>      > test).
>      >
>      > Signed-off-by: Nathan Rossi <nathan at nathanrossi.com
>     <mailto:nathan at nathanrossi.com>>
>      > Cc: Ross Burton <ross.burton at intel.com <mailto:ross.burton at intel.com>>
>      > ---
>      >  meta/recipes-core/busybox/busybox.inc | 6 ++++++
>      >  1 file changed, 6 insertions(+)
>      >
>      > diff --git a/meta/recipes-core/busybox/busybox.inc
>     b/meta/recipes-core/busybox/busybox.inc
>      > index 4012f921c6..157aea3968 100644
>      > --- a/meta/recipes-core/busybox/busybox.inc
>      > +++ b/meta/recipes-core/busybox/busybox.inc
>      > @@ -183,6 +183,12 @@ do_compile() {
>      >                       oe_runmake busybox.links
>      >                       mv busybox.links busybox.links.$s
>      >               done
>      > +
>      > +             # hard fail if sh is being linked to the suid busybox
>     (detects bug 10346)
>      > +             if grep -q -x "/bin/sh" busybox.links.suid; then
>      > +                     bbfatal "busybox suid binary incorrectly provides
>     /bin/sh"
>      > +             fi
>      > +
>      >               # copy .config.orig back to .config, because the install
>     process may check this file
>      >               cp .config.orig .config
>      >               # cleanup
>      >
>     --
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