diff options
Diffstat (limited to 'kernel/bpf')
| -rw-r--r-- | kernel/bpf/verifier.c | 46 |
1 files changed, 29 insertions, 17 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 45733bae271d..faa1ecc1fe9d 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -14212,26 +14212,38 @@ static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn, if (is_kfunc_rcu_protected(&meta)) regs[BPF_REG_0].type |= MEM_RCU; } else { - mark_reg_known_zero(env, regs, BPF_REG_0); - regs[BPF_REG_0].btf = desc_btf; - regs[BPF_REG_0].type = PTR_TO_BTF_ID; - regs[BPF_REG_0].btf_id = ptr_type_id; + enum bpf_reg_type type = PTR_TO_BTF_ID; if (meta.func_id == special_kfunc_list[KF_bpf_get_kmem_cache]) - regs[BPF_REG_0].type |= PTR_UNTRUSTED; - else if (is_kfunc_rcu_protected(&meta)) - regs[BPF_REG_0].type |= MEM_RCU; - - if (is_iter_next_kfunc(&meta)) { - struct bpf_reg_state *cur_iter; - - cur_iter = get_iter_from_state(env->cur_state, &meta); - - if (cur_iter->type & MEM_RCU) /* KF_RCU_PROTECTED */ - regs[BPF_REG_0].type |= MEM_RCU; - else - regs[BPF_REG_0].type |= PTR_TRUSTED; + type |= PTR_UNTRUSTED; + else if (is_kfunc_rcu_protected(&meta) || + (is_iter_next_kfunc(&meta) && + (get_iter_from_state(env->cur_state, &meta) + ->type & MEM_RCU))) { + /* + * If the iterator's constructor (the _new + * function e.g., bpf_iter_task_new) has been + * annotated with BPF kfunc flag + * KF_RCU_PROTECTED and was called within a RCU + * read-side critical section, also propagate + * the MEM_RCU flag to the pointer returned from + * the iterator's next function (e.g., + * bpf_iter_task_next). + */ + type |= MEM_RCU; + } else { + /* + * Any PTR_TO_BTF_ID that is returned from a BPF + * kfunc should by default be treated as + * implicitly trusted. + */ + type |= PTR_TRUSTED; } + + mark_reg_known_zero(env, regs, BPF_REG_0); + regs[BPF_REG_0].btf = desc_btf; + regs[BPF_REG_0].type = type; + regs[BPF_REG_0].btf_id = ptr_type_id; } if (is_kfunc_ret_null(&meta)) { |