From 65269888c695cf4643c6fdb989ea28bf1623685d Mon Sep 17 00:00:00 2001 From: Daniel Xu Date: Wed, 7 Sep 2022 10:40:36 -0600 Subject: [PATCH] bpf: Remove duplicate PTR_TO_BTF_ID RO check Since commit 27ae7997a661 ("bpf: Introduce BPF_PROG_TYPE_STRUCT_OPS") there has existed bpf_verifier_ops:btf_struct_access. When btf_struct_access is _unset_ for a prog type, the verifier runs the default implementation, which is to enforce read only: if (env->ops->btf_struct_access) { [...] } else { if (atype != BPF_READ) { verbose(env, "only read is supported\n"); return -EACCES; } [...] } When btf_struct_access is _set_, the expectation is that btf_struct_access has full control over accesses, including if writes are allowed. Rather than carve out an exception for each prog type that may write to BTF ptrs, delete the redundant check and give full control to btf_struct_access. Signed-off-by: Daniel Xu Acked-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/962da2bff1238746589e332ff1aecc49403cd7ce.1662568410.git.dxu@dxuuu.xyz Signed-off-by: Alexei Starovoitov --- kernel/bpf/verifier.c | 3 --- 1 file changed, 3 deletions(-) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index c0f175ac187a..c3efd461f36c 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -13406,9 +13406,6 @@ static int convert_ctx_accesses(struct bpf_verifier_env *env) insn->code = BPF_LDX | BPF_PROBE_MEM | BPF_SIZE((insn)->code); env->prog->aux->num_exentries++; - } else if (resolve_prog_type(env->prog) != BPF_PROG_TYPE_STRUCT_OPS) { - verbose(env, "Writes through BTF pointers are not allowed\n"); - return -EINVAL; } continue; default: