Re: [LTP] [PATCH] cve-2015-3290: Fix tst_syscall() return value

Petr Vorel
2023-02-15T15:58:00Z

> Hi all,

> On 15/02/2023 15:20, Petr Vorel wrote:
> > Hi all,

> > > The modify_ldt() syscall returns 32-bit signed integer value. Recent changes
> > > in tst_syscall() caused the value to be interpreted as unsigned on older
> > > kernels/glibc, which breaks the cve-2015-3290 test. Add explicit type cast
> > > to fix it.
> > Reviewed-by: Petr Vorel <pvorel@suse.cz>

> > This is caused by e5d2a05a9 ("regen.sh: Use intptr_t for tst_syscall return")
> > which changed returning tst_ret from int to intptr_t (which is also int for 32
> > bit archs, but long for 64 bit archs). This commit is also needed, thus I don't
> > suggest to revert it, but I wonder how many other tests it broke.

> I sent the tst_syscall return patch. I did some testing with what systems I
> had available when working on it and, at the time, didn't see any
> regressions,
> including for cve-2015-3290.

> However this was with fairly recent kernels and libcs, and according to
> Martin
> the test failed for them on an older combination.

FYI I was able to reproduce it on VM with SLE15-SP2 kernel (based on 5.3.18,
with many patches) and glibc 2.26-13.62.1 (obviously older supported systems are
also affected). Hopefully that's all (need to check).

Kind regards,
Petr

> I shared the test suite[0] I tested the patch with, containing all the uses
> I found.
> It might be worthwhile to run it on a system where we now know one of the
> tests
> was affected ? Hopefully, none more, but having a result would be better.

> Best regards,
> Téo

> [0]: https://lists.linux.it/pipermail/ltp/2022-November/031640.html

> > Kind regards,
> > Petr

> > > Signed-off-by: Martin Doucha <mdoucha@suse.cz>
> > > ---
> > > testcases/cve/cve-2015-3290.c | 3 ++-
> > > 1 file changed, 2 insertions(+), 1 deletion(-)
> > > diff --git a/testcases/cve/cve-2015-3290.c b/testcases/cve/cve-2015-3290.c
> > > index f61d2809b..a2a8fcedd 100644
> > > --- a/testcases/cve/cve-2015-3290.c
> > > +++ b/testcases/cve/cve-2015-3290.c
> > > @@ -195,7 +195,8 @@ static void set_ldt(void)
> > > .useable = 0
> > > };
> > > - TEST(tst_syscall(__NR_modify_ldt, 1, &data_desc, sizeof(data_desc)));
> > > + TEST((int)tst_syscall(__NR_modify_ldt, 1, &data_desc,
> > > + sizeof(data_desc)));
> > > if (TST_RET == -EINVAL) {
> > > tst_brk(TCONF | TRERRNO,
> > > "modify_ldt: 16-bit data segments are probably disabled");