On 7/29/20 2:31 AM, Stanislav Fomichev wrote:
This lets us use socket storage from the following hooks:
* BPF_CGROUP_INET_SOCK_CREATE
* BPF_CGROUP_INET_SOCK_RELEASE
* BPF_CGROUP_INET4_POST_BIND
* BPF_CGROUP_INET6_POST_BIND
Using existing 'bpf_sk_storage_get_proto' doesn't work because
second argument is ARG_PTR_TO_SOCKET. Even though
BPF_PROG_TYPE_CGROUP_SOCK hooks operate on 'struct bpf_sock',
the verifier still considers it as a PTR_TO_CTX.
That's why I'm adding another 'bpf_sk_storage_get_cg_sock_proto'
definition strictly for BPF_PROG_TYPE_CGROUP_SOCK which accepts
ARG_PTR_TO_CTX which is really 'struct sock' for this program type.
Cc: Martin KaFai Lau <kafai@xxxxxx>
Signed-off-by: Stanislav Fomichev <sdf@xxxxxxxxxx>
Makes sense, both applied, thanks!
[...]
diff --git a/net/core/filter.c b/net/core/filter.c
index 29e3455122f7..7124f0fe6974 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -6187,6 +6187,7 @@ bool bpf_helper_changes_pkt_data(void *func)
}
const struct bpf_func_proto bpf_event_output_data_proto __weak;
+const struct bpf_func_proto bpf_sk_storage_get_cg_sock_proto __weak;
static const struct bpf_func_proto *
sock_filter_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
@@ -6219,6 +6220,8 @@ sock_filter_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
case BPF_FUNC_get_cgroup_classid:
return &bpf_get_cgroup_classid_curr_proto;
#endif
+ case BPF_FUNC_sk_storage_get:
+ return &bpf_sk_storage_get_cg_sock_proto;
Been wondering whether we need these for connect/sendmsg/etc hooks that operate
on sock_addr, but for those we have them already covered in sock_addr_func_proto()
therefore all good.
sock_addr_func_proto() also lists the BPF_FUNC_sk_storage_delete. Should we add
that one as well for sock_filter_func_proto()? Presumably create/release doesn't
make sense, but any use case for bind hook?
default:
return bpf_base_func_proto(func_id);
}
