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| author | Yonghong Song <yhs@fb.com> | 2020-05-13 21:02:21 +0300 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2020-05-13 22:30:50 +0300 |
| commit | 3c32cc1bceba8a1755dc35cd97516f6c67856844 (patch) | |
| tree | 10e978c4bc1374703070d8ecee9e4e007b13183b /kernel/bpf/btf.c | |
| parent | ab2ee4fcb9d61fd57db70db694adbcf54662bd80 (diff) | |
| download | linux-3c32cc1bceba8a1755dc35cd97516f6c67856844.tar.xz | |
bpf: Enable bpf_iter targets registering ctx argument types
Commit b121b341e598 ("bpf: Add PTR_TO_BTF_ID_OR_NULL
support") adds a field btf_id_or_null_non0_off to
bpf_prog->aux structure to indicate that the
first ctx argument is PTR_TO_BTF_ID reg_type and
all others are PTR_TO_BTF_ID_OR_NULL.
This approach does not really scale if we have
other different reg types in the future, e.g.,
a pointer to a buffer.
This patch enables bpf_iter targets registering ctx argument
reg types which may be different from the default one.
For example, for pointers to structures, the default reg_type
is PTR_TO_BTF_ID for tracing program. The target can register
a particular pointer type as PTR_TO_BTF_ID_OR_NULL which can
be used by the verifier to enforce accesses.
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200513180221.2949882-1-yhs@fb.com
Diffstat (limited to 'kernel/bpf/btf.c')
| -rw-r--r-- | kernel/bpf/btf.c | 15 |
1 files changed, 10 insertions, 5 deletions
diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index dcd233139294..58c9af1d4808 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -3694,7 +3694,7 @@ bool btf_ctx_access(int off, int size, enum bpf_access_type type, struct bpf_verifier_log *log = info->log; const struct btf_param *args; u32 nr_args, arg; - int ret; + int i, ret; if (off % 8) { bpf_log(log, "func '%s' offset %d is not multiple of 8\n", @@ -3790,10 +3790,15 @@ bool btf_ctx_access(int off, int size, enum bpf_access_type type, return true; /* this is a pointer to another type */ - if (off != 0 && prog->aux->btf_id_or_null_non0_off) - info->reg_type = PTR_TO_BTF_ID_OR_NULL; - else - info->reg_type = PTR_TO_BTF_ID; + info->reg_type = PTR_TO_BTF_ID; + for (i = 0; i < prog->aux->ctx_arg_info_size; i++) { + const struct bpf_ctx_arg_aux *ctx_arg_info = &prog->aux->ctx_arg_info[i]; + + if (ctx_arg_info->offset == off) { + info->reg_type = ctx_arg_info->reg_type; + break; + } + } if (tgt_prog) { ret = btf_translate_to_vmlinux(log, btf, t, tgt_prog->type, arg); |