[LTP] [PATCH v1 3/4] syscalls/capset03: add new EPERM error test without CAP_SETPCAP

Cyril Hrubis
2020-01-08T11:03:43Z

Hi!
> >> +static void setup(void)
> >> +{
> >> + pid_t pid;
> >> +
> >> + pid = getpid();
> >> + header.pid = pid;
> >> + if (geteuid() == 0) {
> >> + TEST(tst_syscall(__NR_capset, &header, data));
> >> + if (TST_RET == -1)
> >> + tst_brk(TBROK | TTERRNO, "capset data failed");
> >> + }
> >
> > Please don't do that. If tests needs root (even for a subset of the
> > test) just set the .needs_root flag.
> >
> This test doesn't need root. These code is designed to create a
> envrionment for root user to generate this type EPERM
> error??new_Inheritable is not a subset of old_Inheritable and
> old_Permitted without CAP_SETPCAP??.
> root user:
> old pI: CAP_KILL
> old pP: CAP_KILL
> new pI: CAP_KILL + CAP_NET_RAW
>
> other user:
> old pI: 0
> old pP: 0
> new pI: CAP_KILL + CAP_NET_RAW
>
> other user also met condition and can generate this EPERM error.

Hmm, we are testing different things under root and non-root then. When
the test is executed under a regular user we assert that the system
default is sane + the capset assertion, while under the root we test
only capset.

It would make sense to run the test only under root to make sure that we
are consistent.

Also the CAP_DROP in the tst_test structure seems to be useless to me.

Looking at man 7 capabilities, there are also transitions defined for
what is supposed to happen when we change user id. It would make sense
to write tests that capabilities are correctly dropped when UID changes
from 0 to nonzero. Which is what this test is testing when executed as
non-root, since the transition from 0 to nonzero must have happened
somewhere when user has logged in.

> ps: In capset03, getpid() is useless, we can use pid = 0 to replace.
> Also, if we can use pid =0 in error test, maybe we don't need to test
> pid =0 in capget01/capset01.c . What do you think about it?

Sure. We can use 0 in all tests if we have a least one for each syscall
that tests it with pid != 0.

--
Cyril Hrubis
chrubis@suse.cz