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From: Stanislav Fomichev <sdf@google.com>
To: netdev@vger.kernel.org, bpf@vger.kernel.org
Cc: davem@davemloft.net, ast@kernel.org, daniel@iogearbox.net,
	simon.horman@netronome.com, willemb@google.com,
	peterpenkov96@gmail.com, Stanislav Fomichev <sdf@google.com>
Subject: [RFC bpf-next v2 5/9] flow_dissector: allow access only to a subset of __sk_buff fields
Date: Tue, 19 Mar 2019 15:19:44 -0700	[thread overview]
Message-ID: <20190319221948.170441-6-sdf@google.com> (raw)
In-Reply-To: <20190319221948.170441-1-sdf@google.com>

Use whitelist instead of a blacklist and allow only a small set of
fields that might be relevant in the context of flow dissector:
* len
* protocol
* vlan_present
* vlan_tci
* vlan_proto
* cb

This is required for the eth_get_headlen case where we construct
temporary skb which might not have full/consistent state to let flow
dissector programs access all the fields (which are irrelevant in for
flow dissector program type).

Signed-off-by: Stanislav Fomichev <sdf@google.com>
---
 net/core/filter.c | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/net/core/filter.c b/net/core/filter.c
index 647c63a7b25b..5f413567ce8a 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -6632,11 +6632,14 @@ static bool flow_dissector_is_valid_access(int off, int size,
 	case bpf_ctx_range_ptr(struct __sk_buff, flow_keys):
 		info->reg_type = PTR_TO_FLOW_KEYS;
 		break;
-	case bpf_ctx_range(struct __sk_buff, tc_classid):
-	case bpf_ctx_range(struct __sk_buff, data_meta):
-	case bpf_ctx_range_till(struct __sk_buff, family, local_port):
-	case bpf_ctx_range(struct __sk_buff, tstamp):
-	case bpf_ctx_range(struct __sk_buff, wire_len):
+	case bpf_ctx_range(struct __sk_buff, len):
+	case bpf_ctx_range(struct __sk_buff, protocol):
+	case bpf_ctx_range(struct __sk_buff, vlan_present):
+	case bpf_ctx_range(struct __sk_buff, vlan_tci):
+	case bpf_ctx_range(struct __sk_buff, vlan_proto):
+	case bpf_ctx_range_till(struct __sk_buff, cb[0], cb[4]):
+		break;
+	default:
 		return false;
 	}
 
-- 
2.21.0.225.g810b269d1ac-goog


  parent reply	other threads:[~2019-03-19 22:20 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-03-19 22:19 [RFC bpf-next v2 0/9] net: flow_dissector: trigger BPF hook when called from eth_get_headlen Stanislav Fomichev
2019-03-19 22:19 ` [RFC bpf-next v2 1/9] net: introduce __init_skb{,_data,_shinfo} helpers Stanislav Fomichev
2019-03-21  3:39   ` Alexei Starovoitov
2019-03-21  4:44     ` Eric Dumazet
2019-03-21 13:58       ` Willem de Bruijn
2019-03-21 15:44         ` Stanislav Fomichev
2019-03-21 16:00           ` Alexei Starovoitov
2019-03-21 16:13             ` Willem de Bruijn
2019-03-21 20:56               ` Alexei Starovoitov
2019-03-21 21:13                 ` Stanislav Fomichev
2019-03-19 22:19 ` [RFC bpf-next v2 2/9] net: introduce skb_net helper Stanislav Fomichev
2019-03-20  2:14   ` Willem de Bruijn
2019-03-20 16:49     ` Stanislav Fomichev
2019-03-19 22:19 ` [RFC bpf-next v2 3/9] net: plumb network namespace into __skb_flow_dissect Stanislav Fomichev
2019-03-19 22:19 ` [RFC bpf-next v2 4/9] net: flow_dissector: prepare for no-skb use case Stanislav Fomichev
2019-03-19 22:19 ` Stanislav Fomichev [this message]
2019-03-19 22:19 ` [RFC bpf-next v2 6/9] net: flow_dissector: handle " Stanislav Fomichev
2019-03-19 22:19 ` [RFC bpf-next v2 7/9] bpf: when doing BPF_PROG_TEST_RUN for flow dissector use no-skb mode Stanislav Fomichev
2019-03-20  2:14   ` Willem de Bruijn
2019-03-20 16:57     ` Stanislav Fomichev
2019-03-20 18:29       ` Willem de Bruijn
2019-03-20 19:02         ` Stanislav Fomichev
2019-03-20 19:08           ` Willem de Bruijn
2019-03-20 19:19             ` Stanislav Fomichev
2019-03-20 19:23               ` Willem de Bruijn
2019-03-20 19:48                 ` Stanislav Fomichev
2019-03-20 20:03                   ` Willem de Bruijn
2019-03-19 22:19 ` [RFC bpf-next v2 8/9] selftests/bpf: add flow dissector bpf_skb_load_bytes helper test Stanislav Fomichev
2019-03-19 22:19 ` [RFC bpf-next v2 9/9] net: flow_dissector: pass net argument to the eth_get_headlen Stanislav Fomichev

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