Re: [PATCH v15 05/11] LSM: Create lsm_list_modules system call

From: "Dmitry V. Levin" <ldv@strace.io>
To: Casey Schaufler <casey@schaufler-ca.com>
Cc: 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 12:16:30 +0200	[thread overview]
Message-ID: <20240312101630.GA903@altlinux.org> (raw)
In-Reply-To: <20230912205658.3432-6-casey@schaufler-ca.com>

Hi,

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.

Looks like there has to be a COMPAT_SYSCALL_DEFINE3(lsm_list_modules, ...)
now.  Other two added lsm syscalls also have this issue.

-- 
ldv