Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit e095f0a7 authored by Alexei Starovoitov's avatar Alexei Starovoitov Committed by Harshit Jain
Browse files

BACKPORT: bpf: introduce BPF_PROG_QUERY command 



introduce BPF_PROG_QUERY command to retrieve a set of either
attached programs to given cgroup or a set of effective programs
that will execute for events within a cgroup

Change-Id: I05e0ed5f6eddc30f4a18216d4541448816fd1ae5
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Acked-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Acked-by: default avatarMartin KaFai Lau <kafai@fb.com>
for cgroup bits
Acked-by: default avatarTejun Heo <tj@kernel.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarCyber Knight <cyberknight755@gmail.com>
parent a0bdfd75

include/linux/bpf-cgroup.h

+4 −0
Original line number Diff line number Diff line
@@ -45,12 +45,16 @@ int __cgroup_bpf_attach(struct cgroup *cgrp, struct bpf_prog *prog, 
			enum bpf_attach_type type, u32 flags);

int __cgroup_bpf_detach(struct cgroup *cgrp, struct bpf_prog *prog,

			enum bpf_attach_type type, u32 flags);

int __cgroup_bpf_query(struct cgroup *cgrp, const union bpf_attr *attr,

		       union bpf_attr __user *uattr);



/* Wrapper for __cgroup_bpf_*() protected by cgroup_mutex */

int cgroup_bpf_attach(struct cgroup *cgrp, struct bpf_prog *prog,

		      enum bpf_attach_type type, u32 flags);

int cgroup_bpf_detach(struct cgroup *cgrp, struct bpf_prog *prog,

		      enum bpf_attach_type type, u32 flags);

int cgroup_bpf_query(struct cgroup *cgrp, const union bpf_attr *attr,

		     union bpf_attr __user *uattr);



int __cgroup_bpf_run_filter_skb(struct sock *sk,

				struct sk_buff *skb,

include/linux/bpf.h

+3 −0
Original line number Diff line number Diff line
@@ -296,6 +296,9 @@ struct bpf_prog_array { 


struct bpf_prog_array *bpf_prog_array_alloc(u32 prog_cnt, gfp_t flags);

void bpf_prog_array_free(struct bpf_prog_array __rcu *progs);

int bpf_prog_array_length(struct bpf_prog_array __rcu *progs);

int bpf_prog_array_copy_to_user(struct bpf_prog_array __rcu *progs,

				__u32 __user *prog_ids, u32 cnt);



void bpf_prog_array_delete_safe(struct bpf_prog_array __rcu *progs,

				struct bpf_prog *old_prog);

include/uapi/linux/bpf.h

+13 −0
Original line number Diff line number Diff line
@@ -93,6 +93,7 @@ enum bpf_cmd { 
	BPF_PROG_GET_FD_BY_ID,

	BPF_MAP_GET_FD_BY_ID,

	BPF_OBJ_GET_INFO_BY_FD,

	BPF_PROG_QUERY,

	BPF_BTF_LOAD = 18,

};
@@ -213,6 +214,9 @@ enum bpf_attach_type { 
/* Specify numa node during map creation */

#define BPF_F_NUMA_NODE		(1U << 2)



/* flags for BPF_PROG_QUERY */

#define BPF_F_QUERY_EFFECTIVE	(1U << 0)



#define BPF_OBJ_NAME_LEN 16U



/* Flags for accessing BPF object */
@@ -304,6 +308,15 @@ union bpf_attr { 
		__aligned_u64	info;

	} info;



	struct { /* anonymous struct used by BPF_PROG_QUERY command */

		__u32		target_fd;	/* container object to query */

		__u32		attach_type;

		__u32		query_flags;

		__u32		attach_flags;

		__aligned_u64	prog_ids;

		__u32		prog_cnt;

	} query;



	struct { /* anonymous struct for BPF_BTF_LOAD */

		__aligned_u64	btf;

		__aligned_u64	btf_log_buf;

kernel/bpf/cgroup.c

+46 −0
Original line number Diff line number Diff line
@@ -383,6 +383,52 @@ int __cgroup_bpf_detach(struct cgroup *cgrp, struct bpf_prog *prog, 
	return err;

}



/* Must be called with cgroup_mutex held to avoid races. */

int __cgroup_bpf_query(struct cgroup *cgrp, const union bpf_attr *attr,

		       union bpf_attr __user *uattr)

{

	__u32 __user *prog_ids = u64_to_user_ptr(attr->query.prog_ids);

	enum bpf_attach_type type = attr->query.attach_type;

	struct list_head *progs = &cgrp->bpf.progs[type];

	u32 flags = cgrp->bpf.flags[type];

	int cnt, ret = 0, i;



	if (attr->query.query_flags & BPF_F_QUERY_EFFECTIVE)

		cnt = bpf_prog_array_length(cgrp->bpf.effective[type]);

	else

		cnt = prog_list_length(progs);



	if (copy_to_user(&uattr->query.attach_flags, &flags, sizeof(flags)))

		return -EFAULT;

	if (copy_to_user(&uattr->query.prog_cnt, &cnt, sizeof(cnt)))

		return -EFAULT;

	if (attr->query.prog_cnt == 0 || !prog_ids || !cnt)

		/* return early if user requested only program count + flags */

		return 0;

	if (attr->query.prog_cnt < cnt) {

		cnt = attr->query.prog_cnt;

		ret = -ENOSPC;

	}



	if (attr->query.query_flags & BPF_F_QUERY_EFFECTIVE) {

		return bpf_prog_array_copy_to_user(cgrp->bpf.effective[type],

						   prog_ids, cnt);

	} else {

		struct bpf_prog_list *pl;

		u32 id;



		i = 0;

		list_for_each_entry(pl, progs, node) {

			id = pl->prog->aux->id;

			if (copy_to_user(prog_ids + i, &id, sizeof(id)))

				return -EFAULT;

			if (++i == cnt)

				break;

		}

	}

	return ret;

}



/**

 * __cgroup_bpf_run_filter_skb() - Run a program for packet filtering

 * @sk: The socket sending or receiving traffic

kernel/bpf/core.c

+38 −0
Original line number Diff line number Diff line
@@ -1635,6 +1635,44 @@ int bpf_prog_array_copy(struct bpf_prog_array __rcu *old_array, 
	return 0;

}



int bpf_prog_array_length(struct bpf_prog_array __rcu *progs)

{

	struct bpf_prog **prog;

	u32 cnt = 0;



	rcu_read_lock();

	prog = rcu_dereference(progs)->progs;

	for (; *prog; prog++)

		cnt++;

	rcu_read_unlock();

	return cnt;

}



int bpf_prog_array_copy_to_user(struct bpf_prog_array __rcu *progs,

				__u32 __user *prog_ids, u32 cnt)

{

	struct bpf_prog **prog;

	u32 i = 0, id;



	rcu_read_lock();

	prog = rcu_dereference(progs)->progs;

	for (; *prog; prog++) {

		id = (*prog)->aux->id;

		if (copy_to_user(prog_ids + i, &id, sizeof(id))) {

			rcu_read_unlock();

			return -EFAULT;

		}

		if (++i == cnt) {

			prog++;

			break;

		}

	}

	rcu_read_unlock();

	if (*prog)

		return -ENOSPC;

	return 0;

}



static void bpf_prog_free_deferred(struct work_struct *work)

{

	struct bpf_prog_aux *aux;