From: Chenbo Feng <fe...@google.com>
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.
Signed-off-by: Chenbo Feng <chenbofeng.ker...@gmail.com>
---
include/uapi/linux/bpf.h | 9 ++++++++-
net/core/filter.c | 17 +++++++++++++++++
2 files changed, 25 insertions(+), 1 deletion(-)
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 6923d21..4854027 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -455,6 +455,12 @@ 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), \
@@ -503,7 +509,8 @@ 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 632fb91..523ed08 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -2612,6 +2612,21 @@ 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 = skb->sk;
+ kuid_t kuid = sock_net_uid(net, sk && sk_fullsock(sk) ?
+ sk : NULL);
+ return (u32)kuid.val;
+}
+
+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)
{
@@ -2637,6 +2652,8 @@ bpf_base_func_proto(enum bpf_func_id func_id)
return bpf_get_trace_printk_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 NULL;
}
--
2.7.4
