[PATCH net-next v6 2/3] Add a eBPF helper function to retrieve socket uid
From: Chenbo Feng <hidden>
Date: 2017-03-21 04:09:14
Subsystem:
bpf [general] (safe dynamic programs and tools), bpf [networking] (tcx & tc bpf, sock_addr), networking [general], the rest · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
From: Chenbo Feng <redacted> Returns the owner uid of the socket inside a sk_buff. This is useful to perform per-UID accounting of network traffic or per-UID packet filtering. The socket need to be a fullsock otherwise overflowuid is returned. Signed-off-by: Chenbo Feng <redacted> --- include/uapi/linux/bpf.h | 9 ++++++++- net/core/filter.c | 22 ++++++++++++++++++++++ tools/include/uapi/linux/bpf.h | 3 ++- 3 files changed, 32 insertions(+), 2 deletions(-)
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index dc81a9f..ff42111 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h@@ -462,6 +462,12 @@ union bpf_attr { * @skb: pointer to skb * Return: 8 Bytes non-decreasing number on success or 0 if the socket * field is missing inside sk_buff + * + * u32 bpf_get_socket_uid(skb) + * Get the owner uid of the socket stored inside sk_buff. + * @skb: pointer to skb + * Return: uid of the socket owner on success or 0 if the socket pointer + * inside sk_buff is NULL */ #define __BPF_FUNC_MAPPER(FN) \ FN(unspec), \
@@ -510,7 +516,8 @@ union bpf_attr { FN(skb_change_head), \ FN(xdp_adjust_head), \ FN(probe_read_str), \ - FN(get_socket_cookie), + FN(get_socket_cookie), \ + FN(get_socket_uid), /* integer value in 'imm' field of BPF_CALL instruction selects which helper * function eBPF program intends to call
diff --git a/net/core/filter.c b/net/core/filter.c
index 5b65ae3..2f022df 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c@@ -2612,6 +2612,24 @@ static const struct bpf_func_proto bpf_get_socket_cookie_proto = { .arg1_type = ARG_PTR_TO_CTX, }; +BPF_CALL_1(bpf_get_socket_uid, struct sk_buff *, skb) +{ + struct sock *sk = sk_to_full_sk(skb->sk); + kuid_t kuid; + + if (!sk || !sk_fullsock(sk)) + return overflowuid; + kuid = sock_net_uid(sock_net(sk), sk); + return from_kuid_munged(current_user_ns(), kuid); +} + +static const struct bpf_func_proto bpf_get_socket_uid_proto = { + .func = bpf_get_socket_uid, + .gpl_only = false, + .ret_type = RET_INTEGER, + .arg1_type = ARG_PTR_TO_CTX, +}; + static const struct bpf_func_proto * bpf_base_func_proto(enum bpf_func_id func_id) {
@@ -2648,6 +2666,8 @@ sk_filter_func_proto(enum bpf_func_id func_id) return &bpf_skb_load_bytes_proto; case BPF_FUNC_get_socket_cookie: return &bpf_get_socket_cookie_proto; + case BPF_FUNC_get_socket_uid: + return &bpf_get_socket_uid_proto; default: return bpf_base_func_proto(func_id); }
@@ -2709,6 +2729,8 @@ tc_cls_act_func_proto(enum bpf_func_id func_id) return &bpf_skb_under_cgroup_proto; case BPF_FUNC_get_socket_cookie: return &bpf_get_socket_cookie_proto; + case BPF_FUNC_get_socket_uid: + return &bpf_get_socket_uid_proto; default: return bpf_base_func_proto(func_id); }
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index a94bdd3..4a2d56d 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h@@ -504,7 +504,8 @@ union bpf_attr { FN(skb_change_head), \ FN(xdp_adjust_head), \ FN(probe_read_str), \ - FN(get_socket_cookie), + FN(get_socket_cookie), \ + FN(get_socket_uid), /* integer value in 'imm' field of BPF_CALL instruction selects which helper * function eBPF program intends to call
--
2.7.4