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[2001:8b0:7a5a:26ff::7cf]) by smtp.gmail.com with ESMTPSA id t17-20020adfeb91000000b00307bbbecd29sm16297032wrn.62.2023.05.15.05.15.31 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 15 May 2023 05:15:31 -0700 (PDT) From: Lorenz Bauer To: Martin KaFai Lau , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Song Liu , Yonghong Song , John Fastabend , KP Singh , Stanislav Fomichev , Hao Luo , Jiri Olsa Cc: Lorenz Bauer , bpf@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH bpf-next] bpf: btf: restore resolve_mode when popping the resolve stack Date: Mon, 15 May 2023 13:15:21 +0100 Message-Id: <20230515121521.30569-1-lmb@isovalent.com> X-Mailer: git-send-email 2.40.1 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" In commit 9b459804ff99 ("btf: fix resolving BTF_KIND_VAR after ARRAY, STRUC= T, UNION, PTR") I fixed a bug that occurred during resolving of a DATASEC by strategically = resetting resolve_mode. This fixes the immediate bug but leaves us open to future bug= s where nested types have to be resolved. The problem is that env_stack_pop_resolved never restores the previously ac= tive resolve mode when discarding a stack item. Fix this by adding the previous = resolve mode to each resolve_vertex and updating env->resolve_mode during pop. Signed-off-by: Lorenz Bauer --- kernel/bpf/btf.c | 22 +++++++++++++--------- 1 file changed, 13 insertions(+), 9 deletions(-) diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index 6b682b8e4b50..4d6c1d0e8b7c 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -264,10 +264,19 @@ enum verifier_phase { CHECK_TYPE, }; =20 +enum resolve_mode { + RESOLVE_TBD, /* To Be Determined */ + RESOLVE_PTR, /* Resolving for Pointer */ + RESOLVE_STRUCT_OR_ARRAY, /* Resolving for struct/union + * or array + */ +}; + struct resolve_vertex { const struct btf_type *t; u32 type_id; u16 next_member; + enum resolve_mode parent_mode; }; =20 enum visit_state { @@ -276,13 +285,6 @@ enum visit_state { RESOLVED, }; =20 -enum resolve_mode { - RESOLVE_TBD, /* To Be Determined */ - RESOLVE_PTR, /* Resolving for Pointer */ - RESOLVE_STRUCT_OR_ARRAY, /* Resolving for struct/union - * or array - */ -}; =20 #define MAX_RESOLVE_DEPTH 32 =20 @@ -1811,6 +1813,7 @@ static int env_stack_push(struct btf_verifier_env *en= v, v->t =3D t; v->type_id =3D type_id; v->next_member =3D 0; + v->parent_mode =3D env->resolve_mode; =20 if (env->resolve_mode =3D=3D RESOLVE_TBD) { if (btf_type_is_ptr(t)) @@ -1832,13 +1835,15 @@ static void env_stack_pop_resolved(struct btf_verif= ier_env *env, u32 resolved_type_id, u32 resolved_size) { - u32 type_id =3D env->stack[--(env->top_stack)].type_id; + struct resolve_vertex *v =3D &env->stack[--(env->top_stack)]; + u32 type_id =3D v->type_id; struct btf *btf =3D env->btf; =20 type_id -=3D btf->start_id; /* adjust to local type id */ btf->resolved_sizes[type_id] =3D resolved_size; btf->resolved_ids[type_id] =3D resolved_type_id; env->visit_states[type_id] =3D RESOLVED; + env->resolve_mode =3D v->parent_mode; } =20 static const struct resolve_vertex *env_stack_peak(struct btf_verifier_env= *env) @@ -4541,7 +4546,6 @@ static int btf_datasec_resolve(struct btf_verifier_en= v *env, struct btf *btf =3D env->btf; u16 i; =20 - env->resolve_mode =3D RESOLVE_TBD; for_each_vsi_from(i, v->next_member, v->t, vsi) { u32 var_type_id =3D vsi->type, type_id, type_size =3D 0; const struct btf_type *var_type =3D btf_type_by_id(env->btf, --=20 2.40.1