On 01/11, Will Drewry wrote:
>
> This patch adds support for seccomp mode 2. This mode enables dynamic
> enforcement of system call filtering policy in the kernel as specified
> by a userland task. The policy is expressed in terms of a BPF program,
> as is used for userland-exposed socket filtering. Instead of network
> data, the BPF program is evaluated over struct user_regs_struct at the
> time of the system call (as retrieved using regviews).
Cool ;)
I didn't really read this patch yet, just one nit.
> +#define seccomp_filter_init_task(_tsk) do { \
> + (_tsk)->seccomp.filter = NULL; \
> +} while (0);
Cosmetic and subjective, but imho it would be better to add inline
functions instead of define's.
> @@ -166,6 +167,7 @@ void free_task(struct task_struct *tsk)
> free_thread_info(tsk->stack);
> rt_mutex_debug_task_free(tsk);
> ftrace_graph_exit_task(tsk);
> + seccomp_filter_free_task(tsk);
> free_task_struct(tsk);
> }
> EXPORT_SYMBOL(free_task);
> @@ -1209,6 +1211,7 @@ static struct task_struct *copy_process(unsigned long clone_flags,
> /* Perform scheduler related setup. Assign this task to a CPU. */
> sched_fork(p);
>
> + seccomp_filter_init_task(p);
This doesn't look right or I missed something. something seccomp_filter_init_task()
should be called right after dup_task_struct(), at least before copy process can
fail.
Otherwise copy_process()->free_fork()->seccomp_filter_free_task() can put
current->seccomp.filter copied by arch_dup_task_struct().
> +struct seccomp_filter {
> + struct kref usage;
> + struct pid *creator;
Why? seccomp_filter->creator is never used, no?
Oleg.
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