diff options
Diffstat (limited to 'kernel/bpf/btf.c')
-rw-r--r-- | kernel/bpf/btf.c | 167 |
1 files changed, 146 insertions, 21 deletions
diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index 0493310d981f..563ac61e6d6b 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -3166,9 +3166,16 @@ static void btf_struct_log(struct btf_verifier_env *env, enum btf_field_type { BTF_FIELD_SPIN_LOCK, BTF_FIELD_TIMER, + BTF_FIELD_KPTR, +}; + +enum { + BTF_FIELD_IGNORE = 0, + BTF_FIELD_FOUND = 1, }; struct btf_field_info { + u32 type_id; u32 off; }; @@ -3176,29 +3183,57 @@ static int btf_find_struct(const struct btf *btf, const struct btf_type *t, u32 off, int sz, struct btf_field_info *info) { if (!__btf_type_is_struct(t)) - return 0; + return BTF_FIELD_IGNORE; if (t->size != sz) - return 0; - if (info->off != -ENOENT) - /* only one such field is allowed */ - return -E2BIG; + return BTF_FIELD_IGNORE; info->off = off; - return 0; + return BTF_FIELD_FOUND; +} + +static int btf_find_kptr(const struct btf *btf, const struct btf_type *t, + u32 off, int sz, struct btf_field_info *info) +{ + u32 res_id; + + /* For PTR, sz is always == 8 */ + if (!btf_type_is_ptr(t)) + return BTF_FIELD_IGNORE; + t = btf_type_by_id(btf, t->type); + + if (!btf_type_is_type_tag(t)) + return BTF_FIELD_IGNORE; + /* Reject extra tags */ + if (btf_type_is_type_tag(btf_type_by_id(btf, t->type))) + return -EINVAL; + if (strcmp("kptr", __btf_name_by_offset(btf, t->name_off))) + return -EINVAL; + + /* Get the base type */ + t = btf_type_skip_modifiers(btf, t->type, &res_id); + /* Only pointer to struct is allowed */ + if (!__btf_type_is_struct(t)) + return -EINVAL; + + info->type_id = res_id; + info->off = off; + return BTF_FIELD_FOUND; } static int btf_find_struct_field(const struct btf *btf, const struct btf_type *t, const char *name, int sz, int align, enum btf_field_type field_type, - struct btf_field_info *info) + struct btf_field_info *info, int info_cnt) { const struct btf_member *member; + struct btf_field_info tmp; + int ret, idx = 0; u32 i, off; for_each_member(i, t, member) { const struct btf_type *member_type = btf_type_by_id(btf, member->type); - if (strcmp(__btf_name_by_offset(btf, member_type->name_off), name)) + if (name && strcmp(__btf_name_by_offset(btf, member_type->name_off), name)) continue; off = __btf_member_bit_offset(t, member); @@ -3212,20 +3247,38 @@ static int btf_find_struct_field(const struct btf *btf, const struct btf_type *t switch (field_type) { case BTF_FIELD_SPIN_LOCK: case BTF_FIELD_TIMER: - return btf_find_struct(btf, member_type, off, sz, info); + ret = btf_find_struct(btf, member_type, off, sz, + idx < info_cnt ? &info[idx] : &tmp); + if (ret < 0) + return ret; + break; + case BTF_FIELD_KPTR: + ret = btf_find_kptr(btf, member_type, off, sz, + idx < info_cnt ? &info[idx] : &tmp); + if (ret < 0) + return ret; + break; default: return -EFAULT; } + + if (ret == BTF_FIELD_IGNORE) + continue; + if (idx >= info_cnt) + return -E2BIG; + ++idx; } - return 0; + return idx; } static int btf_find_datasec_var(const struct btf *btf, const struct btf_type *t, const char *name, int sz, int align, enum btf_field_type field_type, - struct btf_field_info *info) + struct btf_field_info *info, int info_cnt) { const struct btf_var_secinfo *vsi; + struct btf_field_info tmp; + int ret, idx = 0; u32 i, off; for_each_vsi(i, t, vsi) { @@ -3234,7 +3287,7 @@ static int btf_find_datasec_var(const struct btf *btf, const struct btf_type *t, off = vsi->offset; - if (strcmp(__btf_name_by_offset(btf, var_type->name_off), name)) + if (name && strcmp(__btf_name_by_offset(btf, var_type->name_off), name)) continue; if (vsi->size != sz) continue; @@ -3244,17 +3297,33 @@ static int btf_find_datasec_var(const struct btf *btf, const struct btf_type *t, switch (field_type) { case BTF_FIELD_SPIN_LOCK: case BTF_FIELD_TIMER: - return btf_find_struct(btf, var_type, off, sz, info); + ret = btf_find_struct(btf, var_type, off, sz, + idx < info_cnt ? &info[idx] : &tmp); + if (ret < 0) + return ret; + break; + case BTF_FIELD_KPTR: + ret = btf_find_kptr(btf, var_type, off, sz, + idx < info_cnt ? &info[idx] : &tmp); + if (ret < 0) + return ret; + break; default: return -EFAULT; } + + if (ret == BTF_FIELD_IGNORE) + continue; + if (idx >= info_cnt) + return -E2BIG; + ++idx; } - return 0; + return idx; } static int btf_find_field(const struct btf *btf, const struct btf_type *t, enum btf_field_type field_type, - struct btf_field_info *info) + struct btf_field_info *info, int info_cnt) { const char *name; int sz, align; @@ -3270,14 +3339,19 @@ static int btf_find_field(const struct btf *btf, const struct btf_type *t, sz = sizeof(struct bpf_timer); align = __alignof__(struct bpf_timer); break; + case BTF_FIELD_KPTR: + name = NULL; + sz = sizeof(u64); + align = 8; + break; default: return -EFAULT; } if (__btf_type_is_struct(t)) - return btf_find_struct_field(btf, t, name, sz, align, field_type, info); + return btf_find_struct_field(btf, t, name, sz, align, field_type, info, info_cnt); else if (btf_type_is_datasec(t)) - return btf_find_datasec_var(btf, t, name, sz, align, field_type, info); + return btf_find_datasec_var(btf, t, name, sz, align, field_type, info, info_cnt); return -EINVAL; } @@ -3287,26 +3361,77 @@ static int btf_find_field(const struct btf *btf, const struct btf_type *t, */ int btf_find_spin_lock(const struct btf *btf, const struct btf_type *t) { - struct btf_field_info info = { .off = -ENOENT }; + struct btf_field_info info; int ret; - ret = btf_find_field(btf, t, BTF_FIELD_SPIN_LOCK, &info); + ret = btf_find_field(btf, t, BTF_FIELD_SPIN_LOCK, &info, 1); if (ret < 0) return ret; + if (!ret) + return -ENOENT; return info.off; } int btf_find_timer(const struct btf *btf, const struct btf_type *t) { - struct btf_field_info info = { .off = -ENOENT }; + struct btf_field_info info; int ret; - ret = btf_find_field(btf, t, BTF_FIELD_TIMER, &info); + ret = btf_find_field(btf, t, BTF_FIELD_TIMER, &info, 1); if (ret < 0) return ret; + if (!ret) + return -ENOENT; return info.off; } +struct bpf_map_value_off *btf_parse_kptrs(const struct btf *btf, + const struct btf_type *t) +{ + struct btf_field_info info_arr[BPF_MAP_VALUE_OFF_MAX]; + struct bpf_map_value_off *tab; + struct btf *kernel_btf = NULL; + int ret, i, nr_off; + + ret = btf_find_field(btf, t, BTF_FIELD_KPTR, info_arr, ARRAY_SIZE(info_arr)); + if (ret < 0) + return ERR_PTR(ret); + if (!ret) + return NULL; + + nr_off = ret; + tab = kzalloc(offsetof(struct bpf_map_value_off, off[nr_off]), GFP_KERNEL | __GFP_NOWARN); + if (!tab) + return ERR_PTR(-ENOMEM); + + for (i = 0; i < nr_off; i++) { + const struct btf_type *t; + s32 id; + + /* Find type in map BTF, and use it to look up the matching type + * in vmlinux or module BTFs, by name and kind. + */ + t = btf_type_by_id(btf, info_arr[i].type_id); + id = bpf_find_btf_id(__btf_name_by_offset(btf, t->name_off), BTF_INFO_KIND(t->info), + &kernel_btf); + if (id < 0) { + ret = id; + goto end; + } + + tab->off[i].offset = info_arr[i].off; + tab->off[i].kptr.btf_id = id; + tab->off[i].kptr.btf = kernel_btf; + } + tab->nr_off = nr_off; + return tab; +end: + while (i--) + btf_put(tab->off[i].kptr.btf); + kfree(tab); + return ERR_PTR(ret); +} + static void __btf_struct_show(const struct btf *btf, const struct btf_type *t, u32 type_id, void *data, u8 bits_offset, struct btf_show *show) |