be8704ff07
Introduce dynamic program extensions. The users can load additional BPF functions and replace global functions in previously loaded BPF programs while these programs are executing. Global functions are verified individually by the verifier based on their types only. Hence the global function in the new program which types match older function can safely replace that corresponding function. This new function/program is called 'an extension' of old program. At load time the verifier uses (attach_prog_fd, attach_btf_id) pair to identify the function to be replaced. The BPF program type is derived from the target program into extension program. Technically bpf_verifier_ops is copied from target program. The BPF_PROG_TYPE_EXT program type is a placeholder. It has empty verifier_ops. The extension program can call the same bpf helper functions as target program. Single BPF_PROG_TYPE_EXT type is used to extend XDP, SKB and all other program types. The verifier allows only one level of replacement. Meaning that the extension program cannot recursively extend an extension. That also means that the maximum stack size is increasing from 512 to 1024 bytes and maximum function nesting level from 8 to 16. The programs don't always consume that much. The stack usage is determined by the number of on-stack variables used by the program. The verifier could have enforced 512 limit for combined original plus extension program, but it makes for difficult user experience. The main use case for extensions is to provide generic mechanism to plug external programs into policy program or function call chaining. BPF trampoline is used to track both fentry/fexit and program extensions because both are using the same nop slot at the beginning of every BPF function. Attaching fentry/fexit to a function that was replaced is not allowed. The opposite is true as well. Replacing a function that currently being analyzed with fentry/fexit is not allowed. The executable page allocated by BPF trampoline is not used by program extensions. This inefficiency will be optimized in future patches. Function by function verification of global function supports scalars and pointer to context only. Hence program extensions are supported for such class of global functions only. In the future the verifier will be extended with support to pointers to structures, arrays with sizes, etc. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: John Fastabend <john.fastabend@gmail.com> Acked-by: Andrii Nakryiko <andriin@fb.com> Acked-by: Toke Høiland-Jørgensen <toke@redhat.com> Link: https://lore.kernel.org/bpf/20200121005348.2769920-2-ast@kernel.org
117 lines
4.6 KiB
C
117 lines
4.6 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/* internal file - do not include directly */
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#ifdef CONFIG_NET
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BPF_PROG_TYPE(BPF_PROG_TYPE_SOCKET_FILTER, sk_filter,
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struct __sk_buff, struct sk_buff)
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BPF_PROG_TYPE(BPF_PROG_TYPE_SCHED_CLS, tc_cls_act,
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struct __sk_buff, struct sk_buff)
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BPF_PROG_TYPE(BPF_PROG_TYPE_SCHED_ACT, tc_cls_act,
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struct __sk_buff, struct sk_buff)
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BPF_PROG_TYPE(BPF_PROG_TYPE_XDP, xdp,
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struct xdp_md, struct xdp_buff)
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#ifdef CONFIG_CGROUP_BPF
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BPF_PROG_TYPE(BPF_PROG_TYPE_CGROUP_SKB, cg_skb,
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struct __sk_buff, struct sk_buff)
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BPF_PROG_TYPE(BPF_PROG_TYPE_CGROUP_SOCK, cg_sock,
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struct bpf_sock, struct sock)
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BPF_PROG_TYPE(BPF_PROG_TYPE_CGROUP_SOCK_ADDR, cg_sock_addr,
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struct bpf_sock_addr, struct bpf_sock_addr_kern)
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#endif
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BPF_PROG_TYPE(BPF_PROG_TYPE_LWT_IN, lwt_in,
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struct __sk_buff, struct sk_buff)
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BPF_PROG_TYPE(BPF_PROG_TYPE_LWT_OUT, lwt_out,
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struct __sk_buff, struct sk_buff)
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BPF_PROG_TYPE(BPF_PROG_TYPE_LWT_XMIT, lwt_xmit,
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struct __sk_buff, struct sk_buff)
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BPF_PROG_TYPE(BPF_PROG_TYPE_LWT_SEG6LOCAL, lwt_seg6local,
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struct __sk_buff, struct sk_buff)
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BPF_PROG_TYPE(BPF_PROG_TYPE_SOCK_OPS, sock_ops,
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struct bpf_sock_ops, struct bpf_sock_ops_kern)
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BPF_PROG_TYPE(BPF_PROG_TYPE_SK_SKB, sk_skb,
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struct __sk_buff, struct sk_buff)
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BPF_PROG_TYPE(BPF_PROG_TYPE_SK_MSG, sk_msg,
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struct sk_msg_md, struct sk_msg)
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BPF_PROG_TYPE(BPF_PROG_TYPE_FLOW_DISSECTOR, flow_dissector,
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struct __sk_buff, struct bpf_flow_dissector)
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#endif
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#ifdef CONFIG_BPF_EVENTS
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BPF_PROG_TYPE(BPF_PROG_TYPE_KPROBE, kprobe,
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bpf_user_pt_regs_t, struct pt_regs)
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BPF_PROG_TYPE(BPF_PROG_TYPE_TRACEPOINT, tracepoint,
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__u64, u64)
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BPF_PROG_TYPE(BPF_PROG_TYPE_PERF_EVENT, perf_event,
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struct bpf_perf_event_data, struct bpf_perf_event_data_kern)
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BPF_PROG_TYPE(BPF_PROG_TYPE_RAW_TRACEPOINT, raw_tracepoint,
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struct bpf_raw_tracepoint_args, u64)
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BPF_PROG_TYPE(BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE, raw_tracepoint_writable,
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struct bpf_raw_tracepoint_args, u64)
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BPF_PROG_TYPE(BPF_PROG_TYPE_TRACING, tracing,
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void *, void *)
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#endif
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#ifdef CONFIG_CGROUP_BPF
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BPF_PROG_TYPE(BPF_PROG_TYPE_CGROUP_DEVICE, cg_dev,
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struct bpf_cgroup_dev_ctx, struct bpf_cgroup_dev_ctx)
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BPF_PROG_TYPE(BPF_PROG_TYPE_CGROUP_SYSCTL, cg_sysctl,
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struct bpf_sysctl, struct bpf_sysctl_kern)
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BPF_PROG_TYPE(BPF_PROG_TYPE_CGROUP_SOCKOPT, cg_sockopt,
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struct bpf_sockopt, struct bpf_sockopt_kern)
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#endif
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#ifdef CONFIG_BPF_LIRC_MODE2
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BPF_PROG_TYPE(BPF_PROG_TYPE_LIRC_MODE2, lirc_mode2,
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__u32, u32)
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#endif
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#ifdef CONFIG_INET
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BPF_PROG_TYPE(BPF_PROG_TYPE_SK_REUSEPORT, sk_reuseport,
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struct sk_reuseport_md, struct sk_reuseport_kern)
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#endif
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#if defined(CONFIG_BPF_JIT)
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BPF_PROG_TYPE(BPF_PROG_TYPE_STRUCT_OPS, bpf_struct_ops,
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void *, void *)
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BPF_PROG_TYPE(BPF_PROG_TYPE_EXT, bpf_extension,
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void *, void *)
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#endif
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BPF_MAP_TYPE(BPF_MAP_TYPE_ARRAY, array_map_ops)
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BPF_MAP_TYPE(BPF_MAP_TYPE_PERCPU_ARRAY, percpu_array_map_ops)
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BPF_MAP_TYPE(BPF_MAP_TYPE_PROG_ARRAY, prog_array_map_ops)
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BPF_MAP_TYPE(BPF_MAP_TYPE_PERF_EVENT_ARRAY, perf_event_array_map_ops)
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#ifdef CONFIG_CGROUPS
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BPF_MAP_TYPE(BPF_MAP_TYPE_CGROUP_ARRAY, cgroup_array_map_ops)
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#endif
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#ifdef CONFIG_CGROUP_BPF
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BPF_MAP_TYPE(BPF_MAP_TYPE_CGROUP_STORAGE, cgroup_storage_map_ops)
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BPF_MAP_TYPE(BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE, cgroup_storage_map_ops)
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#endif
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BPF_MAP_TYPE(BPF_MAP_TYPE_HASH, htab_map_ops)
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BPF_MAP_TYPE(BPF_MAP_TYPE_PERCPU_HASH, htab_percpu_map_ops)
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BPF_MAP_TYPE(BPF_MAP_TYPE_LRU_HASH, htab_lru_map_ops)
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BPF_MAP_TYPE(BPF_MAP_TYPE_LRU_PERCPU_HASH, htab_lru_percpu_map_ops)
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BPF_MAP_TYPE(BPF_MAP_TYPE_LPM_TRIE, trie_map_ops)
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#ifdef CONFIG_PERF_EVENTS
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BPF_MAP_TYPE(BPF_MAP_TYPE_STACK_TRACE, stack_trace_map_ops)
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#endif
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BPF_MAP_TYPE(BPF_MAP_TYPE_ARRAY_OF_MAPS, array_of_maps_map_ops)
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BPF_MAP_TYPE(BPF_MAP_TYPE_HASH_OF_MAPS, htab_of_maps_map_ops)
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#ifdef CONFIG_NET
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BPF_MAP_TYPE(BPF_MAP_TYPE_DEVMAP, dev_map_ops)
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BPF_MAP_TYPE(BPF_MAP_TYPE_DEVMAP_HASH, dev_map_hash_ops)
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BPF_MAP_TYPE(BPF_MAP_TYPE_SK_STORAGE, sk_storage_map_ops)
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#if defined(CONFIG_BPF_STREAM_PARSER)
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BPF_MAP_TYPE(BPF_MAP_TYPE_SOCKMAP, sock_map_ops)
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BPF_MAP_TYPE(BPF_MAP_TYPE_SOCKHASH, sock_hash_ops)
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#endif
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BPF_MAP_TYPE(BPF_MAP_TYPE_CPUMAP, cpu_map_ops)
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#if defined(CONFIG_XDP_SOCKETS)
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BPF_MAP_TYPE(BPF_MAP_TYPE_XSKMAP, xsk_map_ops)
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#endif
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#ifdef CONFIG_INET
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BPF_MAP_TYPE(BPF_MAP_TYPE_REUSEPORT_SOCKARRAY, reuseport_array_ops)
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#endif
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#endif
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BPF_MAP_TYPE(BPF_MAP_TYPE_QUEUE, queue_map_ops)
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BPF_MAP_TYPE(BPF_MAP_TYPE_STACK, stack_map_ops)
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#if defined(CONFIG_BPF_JIT)
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BPF_MAP_TYPE(BPF_MAP_TYPE_STRUCT_OPS, bpf_struct_ops_map_ops)
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#endif
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