Commit 26025bf5 authored by James Morris's avatar James Morris
Browse files

Merge tag 'seccomp-next' of... 

Merge tag 'seccomp-next' of https://git.kernel.org/pub/scm/linux/kernel/git/kees/linux into next-seccomp

add support for retrieving seccomp filter metadata (Tycho Andersen)
parents cf40a76e 26500475

include/linux/seccomp.h

+8 −0
Original line number Diff line number Diff line
@@ -95,11 +95,19 @@ static inline void get_seccomp_filter(struct task_struct *tsk) 
#if defined(CONFIG_SECCOMP_FILTER) && defined(CONFIG_CHECKPOINT_RESTORE)

extern long seccomp_get_filter(struct task_struct *task,

			       unsigned long filter_off, void __user *data);

extern long seccomp_get_metadata(struct task_struct *task,

				 unsigned long filter_off, void __user *data);

#else

static inline long seccomp_get_filter(struct task_struct *task,

				      unsigned long n, void __user *data)

{

	return -EINVAL;

}

static inline long seccomp_get_metadata(struct task_struct *task,

					unsigned long filter_off,

					void __user *data)

{

	return -EINVAL;

}

#endif /* CONFIG_SECCOMP_FILTER && CONFIG_CHECKPOINT_RESTORE */

#endif /* _LINUX_SECCOMP_H */

include/uapi/linux/ptrace.h

+6 −0
Original line number Diff line number Diff line
@@ -66,6 +66,12 @@ struct ptrace_peeksiginfo_args { 
#define PTRACE_SETSIGMASK	0x420b



#define PTRACE_SECCOMP_GET_FILTER	0x420c

#define PTRACE_SECCOMP_GET_METADATA	0x420d



struct seccomp_metadata {

	unsigned long filter_off;	/* Input: which filter */

	unsigned int flags;		/* Output: filter's flags */

};



/* Read signals from a shared (process wide) queue */

#define PTRACE_PEEKSIGINFO_SHARED	(1 << 0)

kernel/ptrace.c

+4 −0
Original line number Diff line number Diff line
@@ -1092,6 +1092,10 @@ int ptrace_request(struct task_struct *child, long request, 
		ret = seccomp_get_filter(child, addr, datavp);

		break;



	case PTRACE_SECCOMP_GET_METADATA:

		ret = seccomp_get_metadata(child, addr, datavp);

		break;



	default:

		break;

	}

kernel/seccomp.c

+76 −30
Original line number Diff line number Diff line
@@ -978,49 +978,68 @@ long prctl_set_seccomp(unsigned long seccomp_mode, char __user *filter) 
}



#if defined(CONFIG_SECCOMP_FILTER) && defined(CONFIG_CHECKPOINT_RESTORE)

long seccomp_get_filter(struct task_struct *task, unsigned long filter_off,

			void __user *data)

static struct seccomp_filter *get_nth_filter(struct task_struct *task,

					     unsigned long filter_off)

{

	struct seccomp_filter *filter;

	struct sock_fprog_kern *fprog;

	long ret;

	unsigned long count = 0;



	if (!capable(CAP_SYS_ADMIN) ||

	    current->seccomp.mode != SECCOMP_MODE_DISABLED) {

		return -EACCES;

	}

	struct seccomp_filter *orig, *filter;

	unsigned long count;



	/*

	 * Note: this is only correct because the caller should be the (ptrace)

	 * tracer of the task, otherwise lock_task_sighand is needed.

	 */

	spin_lock_irq(&task->sighand->siglock);



	if (task->seccomp.mode != SECCOMP_MODE_FILTER) {

		ret = -EINVAL;

		goto out;

		spin_unlock_irq(&task->sighand->siglock);

		return ERR_PTR(-EINVAL);

	}



	filter = task->seccomp.filter;

	while (filter) {

		filter = filter->prev;

	orig = task->seccomp.filter;

	__get_seccomp_filter(orig);

	spin_unlock_irq(&task->sighand->siglock);



	count = 0;

	for (filter = orig; filter; filter = filter->prev)

		count++;

	}



	if (filter_off >= count) {

		ret = -ENOENT;

		filter = ERR_PTR(-ENOENT);

		goto out;

	}

	count -= filter_off;



	filter = task->seccomp.filter;

	while (filter && count > 1) {

		filter = filter->prev;

	count -= filter_off;

	for (filter = orig; filter && count > 1; filter = filter->prev)

		count--;

	}



	if (WARN_ON(count != 1 || !filter)) {

		/* The filter tree shouldn't shrink while we're using it. */

		ret = -ENOENT;

		filter = ERR_PTR(-ENOENT);

		goto out;

	}



	__get_seccomp_filter(filter);



out:

	__put_seccomp_filter(orig);

	return filter;

}



long seccomp_get_filter(struct task_struct *task, unsigned long filter_off,

			void __user *data)

{

	struct seccomp_filter *filter;

	struct sock_fprog_kern *fprog;

	long ret;



	if (!capable(CAP_SYS_ADMIN) ||

	    current->seccomp.mode != SECCOMP_MODE_DISABLED) {

		return -EACCES;

	}



	filter = get_nth_filter(task, filter_off);

	if (IS_ERR(filter))

		return PTR_ERR(filter);



	fprog = filter->prog->orig_prog;

	if (!fprog) {

		/* This must be a new non-cBPF filter, since we save
@@ -1035,17 +1054,44 @@ long seccomp_get_filter(struct task_struct *task, unsigned long filter_off, 
	if (!data)

		goto out;



	__get_seccomp_filter(filter);

	spin_unlock_irq(&task->sighand->siglock);



	if (copy_to_user(data, fprog->filter, bpf_classic_proglen(fprog)))

		ret = -EFAULT;



out:

	__put_seccomp_filter(filter);

	return ret;

}



out:

	spin_unlock_irq(&task->sighand->siglock);

long seccomp_get_metadata(struct task_struct *task,

			  unsigned long size, void __user *data)

{

	long ret;

	struct seccomp_filter *filter;

	struct seccomp_metadata kmd = {};



	if (!capable(CAP_SYS_ADMIN) ||

	    current->seccomp.mode != SECCOMP_MODE_DISABLED) {

		return -EACCES;

	}



	size = min_t(unsigned long, size, sizeof(kmd));



	if (copy_from_user(&kmd, data, size))

		return -EFAULT;



	filter = get_nth_filter(task, kmd.filter_off);

	if (IS_ERR(filter))

		return PTR_ERR(filter);



	memset(&kmd, 0, sizeof(kmd));

	if (filter->log)

		kmd.flags |= SECCOMP_FILTER_FLAG_LOG;



	ret = size;

	if (copy_to_user(data, &kmd, size))

		ret = -EFAULT;



	__put_seccomp_filter(filter);

	return ret;

}

#endif