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| author | Kumar Kartikeya Dwivedi <memxor@gmail.com> | 2022-07-21 15:42:36 +0200 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2022-07-21 21:03:09 -0700 |
| commit | 56e948ffc098a780fefb6c1784a3a2c7b81100a1 (patch) | |
| tree | 3afb22b921df8b7e08b6b034bb51de4dda8c65e7 /net/bpf | |
| parent | a4703e3184320d6e15e2bc81d2ccf1c8c883f9d1 (diff) | |
| download | linux-56e948ffc098a780fefb6c1784a3a2c7b81100a1.tar.bz2 | |
bpf: Add support for forcing kfunc args to be trusted
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>
Diffstat (limited to 'net/bpf')
| -rw-r--r-- | net/bpf/test_run.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c index ca5b7234a350..cbc9cd5058cb 100644 --- a/net/bpf/test_run.c +++ b/net/bpf/test_run.c @@ -691,6 +691,10 @@ noinline void bpf_kfunc_call_test_mem_len_fail2(u64 *mem, int len) { } +noinline void bpf_kfunc_call_test_ref(struct prog_test_ref_kfunc *p) +{ +} + __diag_pop(); ALLOW_ERROR_INJECTION(bpf_modify_return_test, ERRNO); @@ -714,6 +718,7 @@ BTF_ID_FLAGS(func, bpf_kfunc_call_test_fail3) BTF_ID_FLAGS(func, bpf_kfunc_call_test_mem_len_pass1) BTF_ID_FLAGS(func, bpf_kfunc_call_test_mem_len_fail1) BTF_ID_FLAGS(func, bpf_kfunc_call_test_mem_len_fail2) +BTF_ID_FLAGS(func, bpf_kfunc_call_test_ref, KF_TRUSTED_ARGS) BTF_SET8_END(test_sk_check_kfunc_ids) static void *bpf_test_init(const union bpf_attr *kattr, u32 user_size, |