Commit fb85c4a7 authored by Stanislav Fomichev's avatar Stanislav Fomichev Committed by Daniel Borkmann
Browse files

bpf: export bpf_sock for BPF_PROG_TYPE_CGROUP_SOCK_ADDR prog type 



And let it use bpf_sk_storage_{get,delete} helpers to access socket
storage. Kernel context (struct bpf_sock_addr_kern) already has sk
member, so I just expose it to the BPF hooks. Using PTR_TO_SOCKET
instead of PTR_TO_SOCK_COMMON should be safe because the hook is
called on bind/connect.

Cc: Martin Lau <kafai@fb.com>
Signed-off-by: default avatarStanislav Fomichev <sdf@google.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
parent d30bd78c

include/uapi/linux/bpf.h

+1 −0
Original line number Diff line number Diff line
@@ -3247,6 +3247,7 @@ struct bpf_sock_addr { 
	__u32 msg_src_ip6[4];	/* Allows 1,2,4-byte read an 4-byte write.

				 * Stored in network byte order.

				 */

	__bpf_md_ptr(struct bpf_sock *, sk);

};



/* User bpf_sock_ops struct to access socket values and specify request ops

net/core/filter.c

+16 −0
Original line number Diff line number Diff line
@@ -5922,6 +5922,10 @@ sock_addr_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) 
	case BPF_FUNC_skc_lookup_tcp:

		return &bpf_sock_addr_skc_lookup_tcp_proto;

#endif /* CONFIG_INET */

	case BPF_FUNC_sk_storage_get:

		return &bpf_sk_storage_get_proto;

	case BPF_FUNC_sk_storage_delete:

		return &bpf_sk_storage_delete_proto;

	default:

		return bpf_base_func_proto(func_id);

	}
@@ -6828,6 +6832,13 @@ static bool sock_addr_is_valid_access(int off, int size, 
		if (size != size_default)

			return false;

		break;

	case offsetof(struct bpf_sock_addr, sk):

		if (type != BPF_READ)

			return false;

		if (size != sizeof(__u64))

			return false;

		info->reg_type = PTR_TO_SOCKET;

		break;

	default:

		if (type == BPF_READ) {

			if (size != size_default)
@@ -7778,6 +7789,11 @@ static u32 sock_addr_convert_ctx_access(enum bpf_access_type type, 
			struct bpf_sock_addr_kern, struct in6_addr, t_ctx,

			s6_addr32[0], BPF_SIZE(si->code), off, tmp_reg);

		break;

	case offsetof(struct bpf_sock_addr, sk):

		*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_sock_addr_kern, sk),

				      si->dst_reg, si->src_reg,

				      offsetof(struct bpf_sock_addr_kern, sk));

		break;

	}



	return insn - insn_buf;

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