Commit 56fee144 authored by Liu Jian's avatar Liu Jian
Browse files

cgroup: make cgroup_bpf_prog_attach work when cgroup2 is not mounted 

hulk inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I7DNAP


CVE: N/A

----------------------------------------------------

BPF_PROG_TYPE_CGROUP* bpf programs is associated with cgroup2. If cgroup2
is not mounted, the bpf program is associated with cgrp_dfl_root.cgrp
by default.

Then we can use it like below:
bpftool cgroup attach /sys/fs/cgroup/cpu sock_ops pinned /sys/fs/bpf/xxx

Signed-off-by: default avatarLiu Jian <liujian56@huawei.com>
parent 590ef703

include/linux/cgroup.h

+1 −0
Original line number Diff line number Diff line
@@ -106,6 +106,7 @@ struct cgroup_subsys_state *css_tryget_online_from_dir(struct dentry *dentry, 


struct cgroup *cgroup_get_from_path(const char *path);

struct cgroup *cgroup_get_from_fd(int fd);

struct cgroup *cgroup_get_from_fd_v2(int fd);

struct cgroup *cgroup_v1v2_get_from_fd(int fd);



int cgroup_attach_task_all(struct task_struct *from, struct task_struct *);

kernel/bpf/cgroup.c

+4 −4
Original line number Diff line number Diff line
@@ -848,7 +848,7 @@ int cgroup_bpf_prog_attach(const union bpf_attr *attr, 
	struct cgroup *cgrp;

	int ret;



	cgrp = cgroup_get_from_fd(attr->target_fd);

	cgrp = cgroup_get_from_fd_v2(attr->target_fd);

	if (IS_ERR(cgrp))

		return PTR_ERR(cgrp);
@@ -876,7 +876,7 @@ int cgroup_bpf_prog_detach(const union bpf_attr *attr, enum bpf_prog_type ptype) 
	struct cgroup *cgrp;

	int ret;



	cgrp = cgroup_get_from_fd(attr->target_fd);

	cgrp = cgroup_get_from_fd_v2(attr->target_fd);

	if (IS_ERR(cgrp))

		return PTR_ERR(cgrp);
@@ -993,7 +993,7 @@ int cgroup_bpf_link_attach(const union bpf_attr *attr, struct bpf_prog *prog) 
	if (attr->link_create.flags)

		return -EINVAL;



	cgrp = cgroup_get_from_fd(attr->link_create.target_fd);

	cgrp = cgroup_get_from_fd_v2(attr->link_create.target_fd);

	if (IS_ERR(cgrp))

		return PTR_ERR(cgrp);
@@ -1033,7 +1033,7 @@ int cgroup_bpf_prog_query(const union bpf_attr *attr, 
	struct cgroup *cgrp;

	int ret;



	cgrp = cgroup_get_from_fd(attr->query.target_fd);

	cgrp = cgroup_get_from_fd_v2(attr->query.target_fd);

	if (IS_ERR(cgrp))

		return PTR_ERR(cgrp);

kernel/cgroup/cgroup.c

+22 −0
Original line number Diff line number Diff line
@@ -6727,6 +6727,28 @@ struct cgroup *cgroup_get_from_fd(int fd) 
}

EXPORT_SYMBOL_GPL(cgroup_get_from_fd);



/**

 * same with cgroup_get_from_fd, only add cgrp_dfl_visible check

 */

struct cgroup *cgroup_get_from_fd_v2(int fd)

{

	struct cgroup *cgrp = cgroup_v1v2_get_from_fd(fd);



	if (IS_ERR(cgrp))

		return ERR_CAST(cgrp);



	if (!cgroup_on_dfl(cgrp)) {

		cgroup_put(cgrp);

		if (cgrp_dfl_visible)

			return ERR_PTR(-EBADF);



		cgrp = &cgrp_dfl_root.cgrp;

		cgroup_get(cgrp);

	}

	return cgrp;

}

EXPORT_SYMBOL_GPL(cgroup_get_from_fd_v2);



static u64 power_of_ten(int power)

{

	u64 v = 1;