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Message-ID: <20171003055028.1294791-3-ast@fb.com>
Date: Mon, 2 Oct 2017 22:50:22 -0700
From: Alexei Starovoitov <ast@...com>
To: "David S . Miller" <davem@...emloft.net>
CC: Daniel Borkmann <daniel@...earbox.net>, Tejun Heo <tj@...nel.org>,
David Ahern <dsa@...ulusnetworks.com>,
<netdev@...r.kernel.org>, <kernel-team@...com>
Subject: [PATCH v2 net-next 2/8] 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
Signed-off-by: Alexei Starovoitov <ast@...nel.org>
Acked-by: Daniel Borkmann <daniel@...earbox.net>
Acked-by: Martin KaFai Lau <kafai@...com>
for cgroup bits
Acked-by: Tejun Heo <tj@...nel.org>
---
include/linux/bpf-cgroup.h | 4 ++++
include/linux/bpf.h | 3 +++
include/uapi/linux/bpf.h | 13 +++++++++++++
kernel/bpf/cgroup.c | 46 ++++++++++++++++++++++++++++++++++++++++++++++
kernel/bpf/core.c | 38 ++++++++++++++++++++++++++++++++++++++
kernel/bpf/syscall.c | 34 ++++++++++++++++++++++++++++++++++
kernel/cgroup/cgroup.c | 10 ++++++++++
7 files changed, 148 insertions(+)
diff --git a/include/linux/bpf-cgroup.h b/include/linux/bpf-cgroup.h
index 102e56fbb6de..359b6f5d3d90 100644
--- a/include/linux/bpf-cgroup.h
+++ b/include/linux/bpf-cgroup.h
@@ -44,12 +44,16 @@ 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,
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index a6964b75f070..a67daea731ab 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -260,6 +260,9 @@ struct bpf_prog_array {
struct bpf_prog_array __rcu *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);
#define BPF_PROG_RUN_ARRAY(array, ctx, func) \
({ \
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 762f74bc6c47..cb2b9f95160a 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -92,6 +92,7 @@ enum bpf_cmd {
BPF_PROG_GET_FD_BY_ID,
BPF_MAP_GET_FD_BY_ID,
BPF_OBJ_GET_INFO_BY_FD,
+ BPF_PROG_QUERY,
};
enum bpf_map_type {
@@ -211,6 +212,9 @@ 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
union bpf_attr {
@@ -289,6 +293,15 @@ union bpf_attr {
__u32 info_len;
__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;
} __attribute__((aligned(8)));
/* BPF helper function descriptions:
diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c
index 6b7500bbdb53..e88abc0865d5 100644
--- a/kernel/bpf/cgroup.c
+++ b/kernel/bpf/cgroup.c
@@ -384,6 +384,52 @@ 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
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index 6b49e1991ae7..eba966c09053 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -1412,6 +1412,44 @@ void bpf_prog_array_free(struct bpf_prog_array __rcu *progs)
kfree_rcu(progs, rcu);
}
+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;
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 51bee695d32c..0048cb24ba7b 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -1272,6 +1272,37 @@ static int bpf_prog_detach(const union bpf_attr *attr)
return ret;
}
+#define BPF_PROG_QUERY_LAST_FIELD query.prog_cnt
+
+static int bpf_prog_query(const union bpf_attr *attr,
+ union bpf_attr __user *uattr)
+{
+ struct cgroup *cgrp;
+ int ret;
+
+ if (!capable(CAP_NET_ADMIN))
+ return -EPERM;
+ if (CHECK_ATTR(BPF_PROG_QUERY))
+ return -EINVAL;
+ if (attr->query.query_flags & ~BPF_F_QUERY_EFFECTIVE)
+ return -EINVAL;
+
+ switch (attr->query.attach_type) {
+ case BPF_CGROUP_INET_INGRESS:
+ case BPF_CGROUP_INET_EGRESS:
+ case BPF_CGROUP_INET_SOCK_CREATE:
+ case BPF_CGROUP_SOCK_OPS:
+ break;
+ default:
+ return -EINVAL;
+ }
+ cgrp = cgroup_get_from_fd(attr->query.target_fd);
+ if (IS_ERR(cgrp))
+ return PTR_ERR(cgrp);
+ ret = cgroup_bpf_query(cgrp, attr, uattr);
+ cgroup_put(cgrp);
+ return ret;
+}
#endif /* CONFIG_CGROUP_BPF */
#define BPF_PROG_TEST_RUN_LAST_FIELD test.duration
@@ -1568,6 +1599,9 @@ SYSCALL_DEFINE3(bpf, int, cmd, union bpf_attr __user *, uattr, unsigned int, siz
case BPF_PROG_DETACH:
err = bpf_prog_detach(&attr);
break;
+ case BPF_PROG_QUERY:
+ err = bpf_prog_query(&attr, uattr);
+ break;
#endif
case BPF_PROG_TEST_RUN:
err = bpf_prog_test_run(&attr, uattr);
diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index 57eb866ae78d..269512b94a94 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -5761,4 +5761,14 @@ int cgroup_bpf_detach(struct cgroup *cgrp, struct bpf_prog *prog,
mutex_unlock(&cgroup_mutex);
return ret;
}
+int cgroup_bpf_query(struct cgroup *cgrp, const union bpf_attr *attr,
+ union bpf_attr __user *uattr)
+{
+ int ret;
+
+ mutex_lock(&cgroup_mutex);
+ ret = __cgroup_bpf_query(cgrp, attr, uattr);
+ mutex_unlock(&cgroup_mutex);
+ return ret;
+}
#endif /* CONFIG_CGROUP_BPF */
--
2.9.5
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