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author | John Fastabend <john.fastabend@gmail.com> | 2020-05-24 18:50:55 +0200 |
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committer | Alexei Starovoitov <ast@kernel.org> | 2020-06-01 23:38:20 +0200 |
commit | f470378c7562a2818b45ed11c98973f2b89eedd3 (patch) | |
tree | 644a058b0dd4945cc4fe53c4e07c299ba68d16a7 /kernel/bpf | |
parent | bpf, sk_msg: Add some generic helpers that may be useful from sk_msg (diff) | |
download | linux-f470378c7562a2818b45ed11c98973f2b89eedd3.tar.xz linux-f470378c7562a2818b45ed11c98973f2b89eedd3.zip |
bpf: Extend bpf_base_func_proto helpers with probe_* and *current_task*
Often it is useful when applying policy to know something about the
task. If the administrator has CAP_SYS_ADMIN rights then they can
use kprobe + networking hook and link the two programs together to
accomplish this. However, this is a bit clunky and also means we have
to call both the network program and kprobe program when we could just
use a single program and avoid passing metadata through sk_msg/skb->cb,
socket, maps, etc.
To accomplish this add probe_* helpers to bpf_base_func_proto programs
guarded by a perfmon_capable() check. New supported helpers are the
following,
BPF_FUNC_get_current_task
BPF_FUNC_probe_read_user
BPF_FUNC_probe_read_kernel
BPF_FUNC_probe_read_user_str
BPF_FUNC_probe_read_kernel_str
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/159033905529.12355.4368381069655254932.stgit@john-Precision-5820-Tower
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'kernel/bpf')
-rw-r--r-- | kernel/bpf/helpers.c | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index 886949fdcece..bb4fb634275e 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -601,6 +601,12 @@ const struct bpf_func_proto bpf_event_output_data_proto = { .arg5_type = ARG_CONST_SIZE_OR_ZERO, }; +const struct bpf_func_proto bpf_get_current_task_proto __weak; +const struct bpf_func_proto bpf_probe_read_user_proto __weak; +const struct bpf_func_proto bpf_probe_read_user_str_proto __weak; +const struct bpf_func_proto bpf_probe_read_kernel_proto __weak; +const struct bpf_func_proto bpf_probe_read_kernel_str_proto __weak; + const struct bpf_func_proto * bpf_base_func_proto(enum bpf_func_id func_id) { @@ -648,6 +654,24 @@ bpf_base_func_proto(enum bpf_func_id func_id) case BPF_FUNC_jiffies64: return &bpf_jiffies64_proto; default: + break; + } + + if (!perfmon_capable()) + return NULL; + + switch (func_id) { + case BPF_FUNC_get_current_task: + return &bpf_get_current_task_proto; + case BPF_FUNC_probe_read_user: + return &bpf_probe_read_user_proto; + case BPF_FUNC_probe_read_kernel: + return &bpf_probe_read_kernel_proto; + case BPF_FUNC_probe_read_user_str: + return &bpf_probe_read_user_str_proto; + case BPF_FUNC_probe_read_kernel_str: + return &bpf_probe_read_kernel_str_proto; + default: return NULL; } } |