From b39b5f411dcfce28ff954e5d6acb2c11be3cb0ec Mon Sep 17 00:00:00 2001 From: Song Liu Date: Fri, 19 Oct 2018 09:57:57 -0700 Subject: bpf: add cg_skb_is_valid_access for BPF_PROG_TYPE_CGROUP_SKB BPF programs of BPF_PROG_TYPE_CGROUP_SKB need to access headers in the skb. This patch enables direct access of skb for these programs. Two helper functions bpf_compute_and_save_data_end() and bpf_restore_data_end() are introduced. There are used in __cgroup_bpf_run_filter_skb(), to compute proper data_end for the BPF program, and restore original data afterwards. Signed-off-by: Song Liu Signed-off-by: Alexei Starovoitov --- net/core/filter.c | 36 +++++++++++++++++++++++++++++++++++- 1 file changed, 35 insertions(+), 1 deletion(-) (limited to 'net') diff --git a/net/core/filter.c b/net/core/filter.c index ea48ec789b5c..5fd5139e8638 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -5352,6 +5352,40 @@ static bool sk_filter_is_valid_access(int off, int size, return bpf_skb_is_valid_access(off, size, type, prog, info); } +static bool cg_skb_is_valid_access(int off, int size, + enum bpf_access_type type, + const struct bpf_prog *prog, + struct bpf_insn_access_aux *info) +{ + switch (off) { + case bpf_ctx_range(struct __sk_buff, tc_classid): + case bpf_ctx_range(struct __sk_buff, data_meta): + case bpf_ctx_range(struct __sk_buff, flow_keys): + return false; + } + if (type == BPF_WRITE) { + switch (off) { + case bpf_ctx_range(struct __sk_buff, mark): + case bpf_ctx_range(struct __sk_buff, priority): + case bpf_ctx_range_till(struct __sk_buff, cb[0], cb[4]): + break; + default: + return false; + } + } + + switch (off) { + case bpf_ctx_range(struct __sk_buff, data): + info->reg_type = PTR_TO_PACKET; + break; + case bpf_ctx_range(struct __sk_buff, data_end): + info->reg_type = PTR_TO_PACKET_END; + break; + } + + return bpf_skb_is_valid_access(off, size, type, prog, info); +} + static bool lwt_is_valid_access(int off, int size, enum bpf_access_type type, const struct bpf_prog *prog, @@ -7044,7 +7078,7 @@ const struct bpf_prog_ops xdp_prog_ops = { const struct bpf_verifier_ops cg_skb_verifier_ops = { .get_func_proto = cg_skb_func_proto, - .is_valid_access = sk_filter_is_valid_access, + .is_valid_access = cg_skb_is_valid_access, .convert_ctx_access = bpf_convert_ctx_access, }; -- cgit v1.2.3