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authorStanislav Fomichev <sdf@google.com>2019-04-25 14:37:23 -0700
committerDaniel Borkmann <daniel@iogearbox.net>2019-04-25 23:49:06 +0200
commit118c8e9ae629d35fa9b3d27a7b9d59298b1b4183 (patch)
tree7ac43c744fec6cdd282557b4c56d30141dba3161
parentead442a0f9aaecb4df3eb4055d1e2568b4fc0ae6 (diff)
bpf: support BPF_PROG_QUERY for BPF_FLOW_DISSECTOR attach_type
target_fd is target namespace. If there is a flow dissector BPF program attached to that namespace, its (single) id is returned. v5: * drop net ref right after rcu unlock (Daniel Borkmann) v4: * add missing put_net (Jann Horn) v3: * add missing inline to skb_flow_dissector_prog_query static def (kbuild test robot <lkp@intel.com>) v2: * don't sleep in rcu critical section (Jakub Kicinski) * check input prog_cnt (exit early) Cc: Jann Horn <jannh@google.com> Signed-off-by: Stanislav Fomichev <sdf@google.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
-rw-r--r--include/linux/skbuff.h8
-rw-r--r--kernel/bpf/syscall.c2
-rw-r--r--net/core/flow_dissector.c39
3 files changed, 49 insertions, 0 deletions
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 998256c2820b..6d58fa8a65fd 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -1258,11 +1258,19 @@ void skb_flow_dissector_init(struct flow_dissector *flow_dissector,
unsigned int key_count);
#ifdef CONFIG_NET
+int skb_flow_dissector_prog_query(const union bpf_attr *attr,
+ union bpf_attr __user *uattr);
int skb_flow_dissector_bpf_prog_attach(const union bpf_attr *attr,
struct bpf_prog *prog);
int skb_flow_dissector_bpf_prog_detach(const union bpf_attr *attr);
#else
+static inline int skb_flow_dissector_prog_query(const union bpf_attr *attr,
+ union bpf_attr __user *uattr)
+{
+ return -EOPNOTSUPP;
+}
+
static inline int skb_flow_dissector_bpf_prog_attach(const union bpf_attr *attr,
struct bpf_prog *prog)
{
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 92c9b8a32b50..b0de49598341 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -2009,6 +2009,8 @@ static int bpf_prog_query(const union bpf_attr *attr,
break;
case BPF_LIRC_MODE2:
return lirc_prog_query(attr, uattr);
+ case BPF_FLOW_DISSECTOR:
+ return skb_flow_dissector_prog_query(attr, uattr);
default:
return -EINVAL;
}
diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c
index fac712cee9d5..9ca784c592ac 100644
--- a/net/core/flow_dissector.c
+++ b/net/core/flow_dissector.c
@@ -65,6 +65,45 @@ void skb_flow_dissector_init(struct flow_dissector *flow_dissector,
}
EXPORT_SYMBOL(skb_flow_dissector_init);
+int skb_flow_dissector_prog_query(const union bpf_attr *attr,
+ union bpf_attr __user *uattr)
+{
+ __u32 __user *prog_ids = u64_to_user_ptr(attr->query.prog_ids);
+ u32 prog_id, prog_cnt = 0, flags = 0;
+ struct bpf_prog *attached;
+ struct net *net;
+
+ if (attr->query.query_flags)
+ return -EINVAL;
+
+ net = get_net_ns_by_fd(attr->query.target_fd);
+ if (IS_ERR(net))
+ return PTR_ERR(net);
+
+ rcu_read_lock();
+ attached = rcu_dereference(net->flow_dissector_prog);
+ if (attached) {
+ prog_cnt = 1;
+ prog_id = attached->aux->id;
+ }
+ rcu_read_unlock();
+
+ put_net(net);
+
+ if (copy_to_user(&uattr->query.attach_flags, &flags, sizeof(flags)))
+ return -EFAULT;
+ if (copy_to_user(&uattr->query.prog_cnt, &prog_cnt, sizeof(prog_cnt)))
+ return -EFAULT;
+
+ if (!attr->query.prog_cnt || !prog_ids || !prog_cnt)
+ return 0;
+
+ if (copy_to_user(prog_ids, &prog_id, sizeof(u32)))
+ return -EFAULT;
+
+ return 0;
+}
+
int skb_flow_dissector_bpf_prog_attach(const union bpf_attr *attr,
struct bpf_prog *prog)
{