Re: [PATCH bpf-next 1/2] bpf: expose socket storage to BPF_PROG_TYPE_CGROUP_SOCK
From: Daniel Borkmann <daniel@iogearbox.net>
Date: 2020-07-29 22:52:38
Also in:
bpf
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 <redacted> Signed-off-by: Stanislav Fomichev <redacted>
Makes sense, both applied, thanks! [...]
quoted hunk ↗ jump to hunk
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); }