On Tue, Nov 15, 2022 at 12:45:30AM +0530, Kumar Kartikeya Dwivedi wrote:
> + parse:
> + if (!tab) {
> + tab = kzalloc(offsetof(struct btf_struct_metas, types[1]),
> + GFP_KERNEL | __GFP_NOWARN);
> + if (!tab)
> + return ERR_PTR(-ENOMEM);
> + } else {
> + struct btf_struct_metas *new_tab;
> +
> + new_tab = krealloc(tab, offsetof(struct btf_struct_metas, types[tab->cnt + 1]),
> + GFP_KERNEL | __GFP_NOWARN);
> + if (!new_tab) {
> + ret = -ENOMEM;
> + goto free;
> + }
> + tab = new_tab;
> + }
If @p is %NULL, krealloc() behaves exactly like kmalloc().
That can help to simplify above a bit?
> + type = &tab->types[tab->cnt];
> +
> + type->btf_id = i;
> + record = btf_parse_fields(btf, t, BPF_SPIN_LOCK | BPF_LIST_HEAD | BPF_LIST_NODE, t->size);
> + if (IS_ERR_OR_NULL(record)) {
> + ret = PTR_ERR_OR_ZERO(record) ?: -EFAULT;
> + goto free;
> + }
> + foffs = btf_parse_field_offs(record);
> + if (WARN_ON_ONCE(IS_ERR_OR_NULL(foffs))) {
WARN_ON_ONCE ?
Pls add a comment.
> + btf_record_free(record);
> + ret = -EFAULT;
> + goto free;
> + }
> + type->record = record;
> + type->field_offs = foffs;
> + tab->cnt++;
> + }
> + return tab;
> +free:
> + btf_struct_metas_free(tab);
> + return ERR_PTR(ret);
> +}
> +
> +struct btf_struct_meta *btf_find_struct_meta(const struct btf *btf, u32 btf_id)
> +{
> + struct btf_struct_metas *tab;
> +
> + BUILD_BUG_ON(offsetof(struct btf_struct_meta, btf_id) != 0);
> + tab = btf->struct_meta_tab;
> + if (!tab)
> + return NULL;
> + return bsearch(&btf_id, tab->types, tab->cnt, sizeof(tab->types[0]), btf_id_cmp_func);
> +}
> +
> static int btf_check_type_tags(struct btf_verifier_env *env,
> struct btf *btf, int start_id)
> {
> @@ -5191,6 +5338,7 @@ static int btf_check_type_tags(struct btf_verifier_env *env,
> static struct btf *btf_parse(bpfptr_t btf_data, u32 btf_data_size,
> u32 log_level, char __user *log_ubuf, u32 log_size)
> {
> + struct btf_struct_metas *struct_meta_tab;
> struct btf_verifier_env *env = NULL;
> struct bpf_verifier_log *log;
> struct btf *btf = NULL;
> @@ -5259,15 +5407,24 @@ static struct btf *btf_parse(bpfptr_t btf_data, u32 btf_data_size,
> if (err)
> goto errout;
>
> + struct_meta_tab = btf_parse_struct_metas(log, btf);
> + if (IS_ERR(struct_meta_tab)) {
> + err = PTR_ERR(struct_meta_tab);
> + goto errout;
> + }
> + btf->struct_meta_tab = struct_meta_tab;
> +
> if (log->level && bpf_verifier_log_full(log)) {
> err = -ENOSPC;
> - goto errout;
> + goto errout_meta;
> }
>
> btf_verifier_env_free(env);
> refcount_set(&btf->refcnt, 1);
> return btf;
>
> +errout_meta:
> + btf_free_struct_meta_tab(btf);
> errout:
> btf_verifier_env_free(env);
> if (btf)
> @@ -6028,6 +6185,28 @@ int btf_struct_access(struct bpf_verifier_log *log,
> u32 id = reg->btf_id;
> int err;
>
> + while (type_is_alloc(reg->type)) {
> + struct btf_struct_meta *meta;
> + struct btf_record *rec;
> + int i;
> +
> + meta = btf_find_struct_meta(btf, id);
> + if (!meta)
> + break;
> + rec = meta->record;
> + for (i = 0; i < rec->cnt; i++) {
> + struct btf_field *field = &rec->fields[i];
> + u32 offset = field->offset;
> + if (off < offset + btf_field_type_size(field->type) && offset < off + size) {
> + bpf_log(log,
> + "direct access to %s is disallowed\n",
> + btf_field_type_name(field->type));
> + return -EACCES;
> + }
> + }
> + break;
> + }
> +
> t = btf_type_by_id(btf, id);
> do {
> err = btf_struct_walk(log, btf, t, off, size, &id, &tmp_flag);
> @@ -7269,23 +7448,6 @@ bool btf_is_module(const struct btf *btf)
> return btf->kernel_btf && strcmp(btf->name, "vmlinux") != 0;
> }
>
> -static int btf_id_cmp_func(const void *a, const void *b)
> -{
> - const int *pa = a, *pb = b;
> -
> - return *pa - *pb;
> -}
> -
> -bool btf_id_set_contains(const struct btf_id_set *set, u32 id)
> -{
> - return bsearch(&id, set->ids, set->cnt, sizeof(u32), btf_id_cmp_func) != NULL;
> -}
> -
> -static void *btf_id_set8_contains(const struct btf_id_set8 *set, u32 id)
> -{
> - return bsearch(&id, set->pairs, set->cnt, sizeof(set->pairs[0]), btf_id_cmp_func);
> -}
> -
> enum {
> BTF_MODULE_F_LIVE = (1 << 0),
> };
> diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
> index fdbae52f463f..c96039a4e57f 100644
> --- a/kernel/bpf/syscall.c
> +++ b/kernel/bpf/syscall.c
> @@ -537,6 +537,7 @@ void btf_record_free(struct btf_record *rec)
> btf_put(rec->fields[i].kptr.btf);
> break;
> case BPF_LIST_HEAD:
> + case BPF_LIST_NODE:
> /* Nothing to release for bpf_list_head */
> break;
> default:
> @@ -582,6 +583,7 @@ struct btf_record *btf_record_dup(const struct btf_record *rec)
> }
> break;
> case BPF_LIST_HEAD:
> + case BPF_LIST_NODE:
> /* Nothing to acquire for bpf_list_head */
> break;
> default:
> @@ -648,6 +650,8 @@ void bpf_obj_free_fields(const struct btf_record *rec, void *obj)
> continue;
> bpf_list_head_free(field, field_ptr, obj + rec->spin_lock_off);
> break;
> + case BPF_LIST_NODE:
> + break;
> default:
> WARN_ON_ONCE(1);
> continue;
> --
> 2.38.1
>
