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authorSong Liu <songliubraving@fb.com>2018-10-19 09:57:57 -0700
committerAlexei Starovoitov <ast@kernel.org>2018-10-19 13:49:34 -0700
commitb39b5f411dcfce28ff954e5d6acb2c11be3cb0ec (patch)
tree4f724a3269469e76ed30c674bf52ddef3fb93db0 /net
parent2929ad29a3015120ab64c86f362fc2a590ceb69c (diff)
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 <songliubraving@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'net')
-rw-r--r--net/core/filter.c36
1 files changed, 35 insertions, 1 deletions
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,
};