56e948ffc0
Teach the verifier to detect a new KF_TRUSTED_ARGS kfunc flag, which means each pointer argument must be trusted, which we define as a pointer that is referenced (has non-zero ref_obj_id) and also needs to have its offset unchanged, similar to how release functions expect their argument. This allows a kfunc to receive pointer arguments unchanged from the result of the acquire kfunc. This is required to ensure that kfunc that operate on some object only work on acquired pointers and not normal PTR_TO_BTF_ID with same type which can be obtained by pointer walking. The restrictions applied to release arguments also apply to trusted arguments. This implies that strict type matching (not deducing type by recursively following members at offset) and OBJ_RELEASE offset checks (ensuring they are zero) are used for trusted pointer arguments. Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> Link: https://lore.kernel.org/r/20220721134245.2450-5-memxor@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org> |
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| Makefile | ||
| bpf_dummy_struct_ops.c | ||
| test_run.c | ||