[LTP] [PATCH] open|creat: skip S_ISGID check on files created by non-group members

[Jan Stancek <jstancek@redhat.com>]

----- Original Message -----
> Hi!
> > 0fa3ecd87848 ("Fix up non-directory creation in SGID directories")
> > fixes problem described in CVE-2018-13405. This commit is getting
> > backported to older streams as well.
> > 
> > This patch removes S_ISGID check for files created by non-group members
> > in LTP tests creat08 and open10.
> 
> Looks good, acked.

Thanks, I almost forgot about this. Pushed.

Regards,
Jan

> 
> > Once 0fa3ecd87848 will be in non-rc kernel, we could add a new test
> > for this CVE that would be limited to 4.18+ kernels.
> 
> Given that this is CVE we may as well go a little bit further and write
> a test that will fail even on older kernels.
> 
> > Signed-off-by: Jan Stancek <jstancek@redhat.com>
> > ---
> >  testcases/kernel/syscalls/creat/creat08.c | 13 ++++++-------
> >  testcases/kernel/syscalls/open/open10.c   | 12 +++++-------
> >  2 files changed, 11 insertions(+), 14 deletions(-)
> > 
> > diff --git a/testcases/kernel/syscalls/creat/creat08.c
> > b/testcases/kernel/syscalls/creat/creat08.c
> > index 50f2b39931b8..d22558ac3c53 100644
> > --- a/testcases/kernel/syscalls/creat/creat08.c
> > +++ b/testcases/kernel/syscalls/creat/creat08.c
> > @@ -361,13 +361,12 @@ int main(int ac, char **av)
> >  			local_flag = FAILED;
> >  		}
> >  
> > -		/* Verify modes */
> > -		if (!(buf.st_mode & S_ISGID)) {
> > -			tst_resm(TFAIL,
> > -				 "%s: Incorrect modes, setgid bit should be set",
> > -				 setgid_B);
> > -			local_flag = FAILED;
> > -		}
> > +		/*
> > +		 * Skip S_ISGID check
> > +		 * 0fa3ecd87848 ("Fix up non-directory creation in SGID directories")
> > +		 * clears S_ISGID for files created by non-group members
> > +		 */
> > +
> >  		close(fd);
> >  
> >  		if (local_flag == PASSED) {
> > diff --git a/testcases/kernel/syscalls/open/open10.c
> > b/testcases/kernel/syscalls/open/open10.c
> > index 613f2288fbde..14feec9e127e 100644
> > --- a/testcases/kernel/syscalls/open/open10.c
> > +++ b/testcases/kernel/syscalls/open/open10.c
> > @@ -345,13 +345,11 @@ int main(int ac, char *av[])
> >  			local_flag = FAILED;
> >  		}
> >  
> > -		/* Verify modes */
> > -		if (!(buf.st_mode & S_ISGID)) {
> > -			tst_resm(TFAIL,
> > -				 "%s: Incorrect modes, setgid bit not set",
> > -				 setgid_B);
> > -			local_flag = FAILED;
> > -		}
> > +		/*
> > +		 * Skip S_ISGID check
> > +		 * 0fa3ecd87848 ("Fix up non-directory creation in SGID directories")
> > +		 * clears S_ISGID for files created by non-group members
> > +		 */
> >  
> >  		if (local_flag == PASSED) {
> >  			tst_resm(TPASS, "Test passed in block2.");
> > --
> > 1.8.3.1
> > 
> > 
> > --
> > Mailing list info: https://lists.linux.it/listinfo/ltp
> 
> --
> Cyril Hrubis
> chrubis@suse.cz
>