From: Paul Moore <paul@paul-moore.com>
To: Casey Schaufler <casey@schaufler-ca.com>
Cc: "Dmitry V. Levin" <ldv@strace.io>,
linux-security-module@vger.kernel.org, jmorris@namei.org,
serge@hallyn.com, keescook@chromium.org,
john.johansen@canonical.com, penguin-kernel@i-love.sakura.ne.jp,
stephen.smalley.work@gmail.com, linux-kernel@vger.kernel.org,
linux-api@vger.kernel.org, mic@digikod.net
Subject: Re: [PATCH v15 05/11] LSM: Create lsm_list_modules system call
Date: Tue, 12 Mar 2024 19:17:13 -0400 [thread overview]
Message-ID: <CAHC9VhSmZvxkmjeUuYyUZjKDLGpacweLod7rnmeYrWwZH444Sg@mail.gmail.com> (raw)
In-Reply-To: <ad5333de-0c89-4191-a217-014f3953a1df@schaufler-ca.com>
On Tue, Mar 12, 2024 at 6:18 PM Casey Schaufler <casey@schaufler-ca.com> wrote:
> On 3/12/2024 3:06 PM, Paul Moore wrote:
> > On Tue, Mar 12, 2024 at 2:28 PM Dmitry V. Levin <ldv@strace.io> wrote:
> >> On Tue, Mar 12, 2024 at 10:44:38AM -0700, Casey Schaufler wrote:
> >>> On 3/12/2024 10:06 AM, Paul Moore wrote:
> >>>> On Tue, Mar 12, 2024 at 11:27 AM Casey Schaufler <casey@schaufler-ca.com> wrote:
> >>>>> On 3/12/2024 6:25 AM, Paul Moore wrote:
> >>>>>> On Tue, Mar 12, 2024 at 6:16 AM Dmitry V. Levin <ldv@strace.io> wrote:
> >>>>>>> On Tue, Sep 12, 2023 at 01:56:50PM -0700, Casey Schaufler wrote:
> >>>>>>> [...]
> >>>>>>>> --- a/security/lsm_syscalls.c
> >>>>>>>> +++ b/security/lsm_syscalls.c
> >>>>>>>> @@ -55,3 +55,42 @@ SYSCALL_DEFINE4(lsm_get_self_attr, unsigned int, attr, struct lsm_ctx __user *,
> >>>>>>>> {
> >>>>>>>> return security_getselfattr(attr, ctx, size, flags);
> >>>>>>>> }
> >>>>>>>> +
> >>>>>>>> +/**
> >>>>>>>> + * sys_lsm_list_modules - Return a list of the active security modules
> >>>>>>>> + * @ids: the LSM module ids
> >>>>>>>> + * @size: pointer to size of @ids, updated on return
> >>>>>>>> + * @flags: reserved for future use, must be zero
> >>>>>>>> + *
> >>>>>>>> + * Returns a list of the active LSM ids. On success this function
> >>>>>>>> + * returns the number of @ids array elements. This value may be zero
> >>>>>>>> + * if there are no LSMs active. If @size is insufficient to contain
> >>>>>>>> + * the return data -E2BIG is returned and @size is set to the minimum
> >>>>>>>> + * required size. In all other cases a negative value indicating the
> >>>>>>>> + * error is returned.
> >>>>>>>> + */
> >>>>>>>> +SYSCALL_DEFINE3(lsm_list_modules, u64 __user *, ids, size_t __user *, size,
> >>>>>>>> + u32, flags)
> >>>>>>> I'm sorry but the size of userspace size_t is different from the kernel one
> >>>>>>> on 32-bit compat architectures.
> >>>>>> D'oh, yes, thanks for pointing that out. It would have been nice to
> >>>>>> have caught that before v6.8 was released, but I guess it's better
> >>>>>> than later.
> >>>>>>
> >>>>>>> Looks like there has to be a COMPAT_SYSCALL_DEFINE3(lsm_list_modules, ..)
> >>>>>>> now. Other two added lsm syscalls also have this issue.
> >>>>>> Considering that Linux v6.8, and by extension these syscalls, are only
> >>>>>> a few days old, I think I'd rather see us just modify the syscalls and
> >>>>>> avoid the compat baggage. I'm going to be shocked if anyone has
> >>>>>> shifted to using the new syscalls yet, and even if they have (!!),
> >>>>>> moving from a "size_t" type to a "u64" should be mostly transparent
> >>>>>> for the majority of native 64-bit systems. Those running the absolute
> >>>>>> latest kernels on 32-bit systems with custom or bleeding edge
> >>>>>> userspace *may* see a slight hiccup, but I think that user count is in
> >>>>>> the single digits, if not zero.
> >>>>>>
> >>>>>> Let's fix this quickly with /size_t/u64/ in v6.8.1 and avoid the
> >>>>>> compat shim if we can.
> >>>>>>
> >>>>>> Casey, do you have time to put together a patch for this (you should
> >>>>>> fix the call chains below the syscalls too)? If not, please let me
> >>>>>> know and I'll get a patch out ASAP.
> >>>>> Grumble. Yes, I'll get right on it.
> >>>> Great, thanks Casey.
> >>> Look like lsm_get_self_attr() needs the same change. lsm_set_self_attr()
> >>> doesn't, need it, but I'm tempted to change it as well for consistency.
> >>> Thoughts?
> >> As lsm_get_self_attr() has the same issue, it needs the same treatment.
> >>
> >> lsm_set_self_attr() could be left unchanged. In fact, changing the type
> >> of syscall arguments from size_t to an explicit 64-bit type would be
> >> problematic because 32-bit syscalls cannot have 64-bit arguments.
> > You might as well convert all of the size_t parameters, pointers or
> > otherwise, in the three syscalls to u32 Casey.
>
> Well, nuts. So much for that coin flip. V2 coming real soon.
Yeah, sorry for the false starts today ...
--
paul-moore.com
next prev parent reply other threads:[~2024-03-12 23:17 UTC|newest]
Thread overview: 70+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20230912205658.3432-1-casey.ref@schaufler-ca.com>
2023-09-12 20:56 ` [PATCH v15 00/11] LSM: Three basic syscalls Casey Schaufler
2023-09-12 20:56 ` [PATCH v15 01/11] LSM: Identify modules by more than name Casey Schaufler
2023-09-15 11:32 ` Tetsuo Handa
2023-09-15 17:53 ` Casey Schaufler
2023-09-16 6:32 ` Tetsuo Handa
2023-09-17 16:38 ` Casey Schaufler
2023-09-20 10:20 ` Tetsuo Handa
2023-09-20 15:08 ` Kees Cook
2023-09-23 4:46 ` Tetsuo Handa
2023-09-24 1:58 ` Kees Cook
2023-09-24 11:06 ` Tetsuo Handa
2023-09-24 19:48 ` Kees Cook
2023-10-05 12:58 ` Tetsuo Handa
2023-10-20 19:52 ` Casey Schaufler
2023-10-21 12:20 ` Tetsuo Handa
2023-10-21 14:11 ` Casey Schaufler
2023-10-29 10:57 ` Tetsuo Handa
2023-10-29 18:00 ` Casey Schaufler
2023-09-12 20:56 ` [PATCH v15 02/11] LSM: Maintain a table of LSM attribute data Casey Schaufler
2023-09-12 20:56 ` [PATCH v15 03/11] proc: Use lsmids instead of lsm names for attrs Casey Schaufler
2023-09-12 20:56 ` [PATCH v15 04/11] LSM: syscalls for current process attributes Casey Schaufler
2023-10-03 14:09 ` Mickaël Salaün
2023-10-06 1:04 ` Paul Moore
2023-10-09 15:36 ` Mickaël Salaün
2023-10-09 16:04 ` Paul Moore
2023-10-10 9:14 ` Mickaël Salaün
2023-10-10 13:10 ` Paul Moore
2023-09-12 20:56 ` [PATCH v15 05/11] LSM: Create lsm_list_modules system call Casey Schaufler
2023-10-03 14:27 ` Mickaël Salaün
2024-03-12 10:16 ` Dmitry V. Levin
2024-03-12 13:25 ` Paul Moore
2024-03-12 15:27 ` Casey Schaufler
2024-03-12 17:06 ` Paul Moore
2024-03-12 17:44 ` Casey Schaufler
2024-03-12 18:09 ` Paul Moore
2024-03-12 18:28 ` Dmitry V. Levin
2024-03-12 21:50 ` Kees Cook
2024-03-12 22:06 ` Casey Schaufler
2024-03-12 22:06 ` Paul Moore
2024-03-12 22:17 ` Casey Schaufler
2024-03-12 23:17 ` Paul Moore [this message]
2023-09-12 20:56 ` [PATCH v15 06/11] LSM: wireup Linux Security Module syscalls Casey Schaufler
2023-10-03 14:27 ` Mickaël Salaün
2023-09-12 20:56 ` [PATCH v15 07/11] LSM: Helpers for attribute names and filling lsm_ctx Casey Schaufler
2023-10-03 14:28 ` Mickaël Salaün
2023-09-12 20:56 ` [PATCH v15 08/11] Smack: implement setselfattr and getselfattr hooks Casey Schaufler
2023-10-03 14:28 ` Mickaël Salaün
2023-10-20 19:40 ` Casey Schaufler
2023-10-20 19:42 ` Casey Schaufler
2023-09-12 20:56 ` [PATCH v15 09/11] AppArmor: Add selfattr hooks Casey Schaufler
2023-09-12 20:56 ` [PATCH v15 10/11] SELinux: " Casey Schaufler
2023-09-12 20:56 ` [PATCH v15 11/11] LSM: selftests for Linux Security Module syscalls Casey Schaufler
2023-10-03 14:28 ` Mickaël Salaün
2023-10-12 22:07 ` [PATCH v15 00/11] LSM: Three basic syscalls Paul Moore
2023-10-13 21:55 ` Paul Moore
2023-10-16 12:04 ` Roberto Sassu
2023-10-16 15:06 ` Paul Moore
2023-10-17 7:01 ` Roberto Sassu
2023-10-17 15:58 ` Paul Moore
2023-10-17 16:07 ` Roberto Sassu
2023-10-18 9:31 ` Roberto Sassu
2023-10-18 13:09 ` Mimi Zohar
2023-10-18 14:14 ` Roberto Sassu
2023-10-18 16:35 ` Paul Moore
2023-10-18 20:10 ` Mimi Zohar
2023-10-18 20:40 ` Paul Moore
2023-10-19 7:45 ` Roberto Sassu
2023-10-20 16:36 ` Casey Schaufler
2023-10-19 8:49 ` Roberto Sassu
2023-11-13 4:03 ` Paul Moore
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