Jeff Layton писал 14.11.17 23:19:
On Tue, 2017-11-14 at 22:25 +0300, Vitaly Lipatov wrote:
Jeff Layton писал 14.11.17 22:12:
...
> Wait...
>
> Does this do anything at all in the case where you pass in
> COMPAT_LOFF_T_MAX? l_start and l_len are either off_t or loff_t
> (depending on arch).
>
> Either one will fit in the F_GETLK64/F_OFD_GETLK struct, so I don't see
> a need to check here.
I am not sure, can off_t be bigger than loff_t ?
I don't think so, at least not in any possible situation we care about
here.
We have this checking for ages:
if (f.l_start > COMPAT_LOFF_T_MAX)
ret = -EOVERFLOW;
http://debian.securedservers.com/kernel/pub/linux/kernel/people/akpm/patches/2.6/2.6.15-rc5/2.6.15-rc5-mm1/broken-out/fix-overflow-tests-for-compat_sys_fcntl64-locking.patch
If not, we have just skip checking against COMPAT_LOFF_T_MAX.
...
> > @@ -644,7 +644,7 @@ COMPAT_SYSCALL_DEFINE3(fcntl64, unsigned int, fd,
> > unsigned int, cmd,
> > err = fcntl_getlk(f.file, convert_fcntl_cmd(cmd), &flock);
> > if (err)
> > break;
> > - err = fixup_compat_flock(&flock);
> > + err = fixup_compat_flock(&flock, COMPAT_LOFF_T_MAX);
> > if (err)
> > return err;
> > err = put_compat_flock64(&flock, compat_ptr(arg));
>
> Maybe a simpler fix would be to just remove the fixup_compat_flock call
> above?
>
Ok. If you have a test for this, mind testing and sending a patch?
I think if COMPAT_LOFF_T_MAX is exists, that value can be smaller than
can fit in off_t.
Checking against COMPAT_LOFF_T_MAX keep old logic works for me last 10
years.
I have some tests around wine project I worked on. May be later I will
do additional tests.
--
С уважением,
Виталий Липатов,
Etersoft
