From: "Dmitry V. Levin" <ldv@strace.io>
To: Casey Schaufler <casey@schaufler-ca.com>
Cc: Paul Moore <paul@paul-moore.com>,
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 20:28:20 +0200 [thread overview]
Message-ID: <20240312182820.GA5122@altlinux.org> (raw)
In-Reply-To: <f4f5d993-552b-483a-9a3e-1be99ea48757@schaufler-ca.com>
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.
--
ldv
next prev parent reply other threads:[~2024-03-12 18:28 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 [this message]
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
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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