1 files changed, 328 insertions, 40 deletions

diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index 33bb8ae4a804..57f5fd5af2f9 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -198,6 +198,21 @@
 DEFINE_IDR(btf_idr);
 DEFINE_SPINLOCK(btf_idr_lock);
 
+enum btf_kfunc_hook {
+	BTF_KFUNC_HOOK_XDP,
+	BTF_KFUNC_HOOK_TC,
+	BTF_KFUNC_HOOK_STRUCT_OPS,
+	BTF_KFUNC_HOOK_MAX,
+};
+
+enum {
+	BTF_KFUNC_SET_MAX_CNT = 32,
+};
+
+struct btf_kfunc_set_tab {
+	struct btf_id_set *sets[BTF_KFUNC_HOOK_MAX][BTF_KFUNC_TYPE_MAX];
+};
+
 struct btf {
 	void *data;
 	struct btf_type **types;
@@ -212,6 +227,7 @@ struct btf {
 	refcount_t refcnt;
 	u32 id;
 	struct rcu_head rcu;
+	struct btf_kfunc_set_tab *kfunc_set_tab;
 
 	/* split BTF support */
 	struct btf *base_btf;
@@ -1531,8 +1547,30 @@ static void btf_free_id(struct btf *btf)
 	spin_unlock_irqrestore(&btf_idr_lock, flags);
 }
 
+static void btf_free_kfunc_set_tab(struct btf *btf)
+{
+	struct btf_kfunc_set_tab *tab = btf->kfunc_set_tab;
+	int hook, type;
+
+	if (!tab)
+		return;
+	/* For module BTF, we directly assign the sets being registered, so
+	 * there is nothing to free except kfunc_set_tab.
+	 */
+	if (btf_is_module(btf))
+		goto free_tab;
+	for (hook = 0; hook < ARRAY_SIZE(tab->sets); hook++) {
+		for (type = 0; type < ARRAY_SIZE(tab->sets[0]); type++)
+			kfree(tab->sets[hook][type]);
+	}
+free_tab:
+	kfree(tab);
+	btf->kfunc_set_tab = NULL;
+}
+
 static void btf_free(struct btf *btf)
 {
+	btf_free_kfunc_set_tab(btf);
 	kvfree(btf->types);
 	kvfree(btf->resolved_sizes);
 	kvfree(btf->resolved_ids);
@@ -5616,17 +5654,45 @@ static bool __btf_type_is_scalar_struct(struct bpf_verifier_log *log,
 	return true;
 }
 
+static bool is_kfunc_arg_mem_size(const struct btf *btf,
+				  const struct btf_param *arg,
+				  const struct bpf_reg_state *reg)
+{
+	int len, sfx_len = sizeof("__sz") - 1;
+	const struct btf_type *t;
+	const char *param_name;
+
+	t = btf_type_skip_modifiers(btf, arg->type, NULL);
+	if (!btf_type_is_scalar(t) || reg->type != SCALAR_VALUE)
+		return false;
+
+	/* In the future, this can be ported to use BTF tagging */
+	param_name = btf_name_by_offset(btf, arg->name_off);
+	if (str_is_empty(param_name))
+		return false;
+	len = strlen(param_name);
+	if (len < sfx_len)
+		return false;
+	param_name += len - sfx_len;
+	if (strncmp(param_name, "__sz", sfx_len))
+		return false;
+
+	return true;
+}
+
 static int btf_check_func_arg_match(struct bpf_verifier_env *env,
 				    const struct btf *btf, u32 func_id,
 				    struct bpf_reg_state *regs,
 				    bool ptr_to_mem_ok)
 {
 	struct bpf_verifier_log *log = &env->log;
+	u32 i, nargs, ref_id, ref_obj_id = 0;
 	bool is_kfunc = btf_is_kernel(btf);
 	const char *func_name, *ref_tname;
 	const struct btf_type *t, *ref_t;
 	const struct btf_param *args;
-	u32 i, nargs, ref_id;
+	int ref_regno = 0;
+	bool rel = false;
 
 	t = btf_type_by_id(btf, func_id);
 	if (!t || !btf_type_is_func(t)) {
@@ -5704,6 +5770,16 @@ static int btf_check_func_arg_match(struct bpf_verifier_env *env,
 			if (reg->type == PTR_TO_BTF_ID) {
 				reg_btf = reg->btf;
 				reg_ref_id = reg->btf_id;
+				/* Ensure only one argument is referenced PTR_TO_BTF_ID */
+				if (reg->ref_obj_id) {
+					if (ref_obj_id) {
+						bpf_log(log, "verifier internal error: more than one arg with ref_obj_id R%d %u %u\n",
+							regno, reg->ref_obj_id, ref_obj_id);
+						return -EFAULT;
+					}
+					ref_regno = regno;
+					ref_obj_id = reg->ref_obj_id;
+				}
 			} else {
 				reg_btf = btf_vmlinux;
 				reg_ref_id = *reg2btf_ids[reg->type];
@@ -5727,17 +5803,33 @@ static int btf_check_func_arg_match(struct bpf_verifier_env *env,
 			u32 type_size;
 
 			if (is_kfunc) {
+				bool arg_mem_size = i + 1 < nargs && is_kfunc_arg_mem_size(btf, &args[i + 1], &regs[regno + 1]);
+
 				/* Permit pointer to mem, but only when argument
 				 * type is pointer to scalar, or struct composed
 				 * (recursively) of scalars.
+				 * When arg_mem_size is true, the pointer can be
+				 * void *.
 				 */
 				if (!btf_type_is_scalar(ref_t) &&
-				    !__btf_type_is_scalar_struct(log, btf, ref_t, 0)) {
+				    !__btf_type_is_scalar_struct(log, btf, ref_t, 0) &&
+				    (arg_mem_size ? !btf_type_is_void(ref_t) : 1)) {
 					bpf_log(log,
-						"arg#%d pointer type %s %s must point to scalar or struct with scalar\n",
-						i, btf_type_str(ref_t), ref_tname);
+						"arg#%d pointer type %s %s must point to %sscalar, or struct with scalar\n",
+						i, btf_type_str(ref_t), ref_tname, arg_mem_size ? "void, " : "");
 					return -EINVAL;
 				}
+
+				/* Check for mem, len pair */
+				if (arg_mem_size) {
+					if (check_kfunc_mem_size_reg(env, &regs[regno + 1], regno + 1)) {
+						bpf_log(log, "arg#%d arg#%d memory, len pair leads to invalid memory access\n",
+							i, i + 1);
+						return -EINVAL;
+					}
+					i++;
+					continue;
+				}
 			}
 
 			resolve_ret = btf_resolve_size(btf, ref_t, &type_size);
@@ -5758,7 +5850,23 @@ static int btf_check_func_arg_match(struct bpf_verifier_env *env,
 		}
 	}
 
-	return 0;
+	/* Either both are set, or neither */
+	WARN_ON_ONCE((ref_obj_id && !ref_regno) || (!ref_obj_id && ref_regno));
+	if (is_kfunc) {
+		rel = btf_kfunc_id_set_contains(btf, resolve_prog_type(env->prog),
+						BTF_KFUNC_TYPE_RELEASE, func_id);
+		/* We already made sure ref_obj_id is set only for one argument */
+		if (rel && !ref_obj_id) {
+			bpf_log(log, "release kernel function %s expects refcounted PTR_TO_BTF_ID\n",
+				func_name);
+			return -EINVAL;
+		}
+		/* Allow (!rel && ref_obj_id), so that passing such referenced PTR_TO_BTF_ID to
+		 * other kfuncs works
+		 */
+	}
+	/* returns argument register number > 0 in case of reference release kfunc */
+	return rel ? ref_regno : 0;
 }
 
 /* Compare BTF of a function with given bpf_reg_state.
@@ -6200,12 +6308,17 @@ 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;
 }
 
+enum {
+	BTF_MODULE_F_LIVE = (1 << 0),
+};
+
 #ifdef CONFIG_DEBUG_INFO_BTF_MODULES
 struct btf_module {
 	struct list_head list;
 	struct module *module;
 	struct btf *btf;
 	struct bin_attribute *sysfs_attr;
+	int flags;
 };
 
 static LIST_HEAD(btf_modules);
@@ -6233,7 +6346,8 @@ static int btf_module_notify(struct notifier_block *nb, unsigned long op,
 	int err = 0;
 
 	if (mod->btf_data_size == 0 ||
-	    (op != MODULE_STATE_COMING && op != MODULE_STATE_GOING))
+	    (op != MODULE_STATE_COMING && op != MODULE_STATE_LIVE &&
+	     op != MODULE_STATE_GOING))
 		goto out;
 
 	switch (op) {
@@ -6292,6 +6406,17 @@ static int btf_module_notify(struct notifier_block *nb, unsigned long op,
 		}
 
 		break;
+	case MODULE_STATE_LIVE:
+		mutex_lock(&btf_module_mutex);
+		list_for_each_entry_safe(btf_mod, tmp, &btf_modules, list) {
+			if (btf_mod->module != module)
+				continue;
+
+			btf_mod->flags |= BTF_MODULE_F_LIVE;
+			break;
+		}
+		mutex_unlock(&btf_module_mutex);
+		break;
 	case MODULE_STATE_GOING:
 		mutex_lock(&btf_module_mutex);
 		list_for_each_entry_safe(btf_mod, tmp, &btf_modules, list) {
@@ -6338,7 +6463,12 @@ struct module *btf_try_get_module(const struct btf *btf)
 		if (btf_mod->btf != btf)
 			continue;
 
-		if (try_module_get(btf_mod->module))
+		/* We must only consider module whose __init routine has
+		 * finished, hence we must check for BTF_MODULE_F_LIVE flag,
+		 * which is set from the notifier callback for
+		 * MODULE_STATE_LIVE.
+		 */
+		if ((btf_mod->flags & BTF_MODULE_F_LIVE) && try_module_get(btf_mod->module))
 			res = btf_mod->module;
 
 		break;
@@ -6349,6 +6479,36 @@ struct module *btf_try_get_module(const struct btf *btf)
 	return res;
 }
 
+/* Returns struct btf corresponding to the struct module
+ *
+ * This function can return NULL or ERR_PTR. Note that caller must
+ * release reference for struct btf iff btf_is_module is true.
+ */
+static struct btf *btf_get_module_btf(const struct module *module)
+{
+	struct btf *btf = NULL;
+#ifdef CONFIG_DEBUG_INFO_BTF_MODULES
+	struct btf_module *btf_mod, *tmp;
+#endif
+
+	if (!module)
+		return bpf_get_btf_vmlinux();
+#ifdef CONFIG_DEBUG_INFO_BTF_MODULES
+	mutex_lock(&btf_module_mutex);
+	list_for_each_entry_safe(btf_mod, tmp, &btf_modules, list) {
+		if (btf_mod->module != module)
+			continue;
+
+		btf_get(btf_mod->btf);
+		btf = btf_mod->btf;
+		break;
+	}
+	mutex_unlock(&btf_module_mutex);
+#endif
+
+	return btf;
+}
+
 BPF_CALL_4(bpf_btf_find_by_name_kind, char *, name, int, name_sz, u32, kind, int, flags)
 {
 	struct btf *btf;
@@ -6416,53 +6576,181 @@ BTF_ID_LIST_GLOBAL(btf_tracing_ids, MAX_BTF_TRACING_TYPE)
 BTF_TRACING_TYPE_xxx
 #undef BTF_TRACING_TYPE
 
-/* BTF ID set registration API for modules */
-
-#ifdef CONFIG_DEBUG_INFO_BTF_MODULES
+/* Kernel Function (kfunc) BTF ID set registration API */
 
-void register_kfunc_btf_id_set(struct kfunc_btf_id_list *l,
-			       struct kfunc_btf_id_set *s)
+static int __btf_populate_kfunc_set(struct btf *btf, enum btf_kfunc_hook hook,
+				    enum btf_kfunc_type type,
+				    struct btf_id_set *add_set, bool vmlinux_set)
 {
-	mutex_lock(&l->mutex);
-	list_add(&s->list, &l->list);
-	mutex_unlock(&l->mutex);
+	struct btf_kfunc_set_tab *tab;
+	struct btf_id_set *set;
+	u32 set_cnt;
+	int ret;
+
+	if (hook >= BTF_KFUNC_HOOK_MAX || type >= BTF_KFUNC_TYPE_MAX) {
+		ret = -EINVAL;
+		goto end;
+	}
+
+	if (!add_set->cnt)
+		return 0;
+
+	tab = btf->kfunc_set_tab;
+	if (!tab) {
+		tab = kzalloc(sizeof(*tab), GFP_KERNEL | __GFP_NOWARN);
+		if (!tab)
+			return -ENOMEM;
+		btf->kfunc_set_tab = tab;
+	}
+
+	set = tab->sets[hook][type];
+	/* Warn when register_btf_kfunc_id_set is called twice for the same hook
+	 * for module sets.
+	 */
+	if (WARN_ON_ONCE(set && !vmlinux_set)) {
+		ret = -EINVAL;
+		goto end;
+	}
+
+	/* We don't need to allocate, concatenate, and sort module sets, because
+	 * only one is allowed per hook. Hence, we can directly assign the
+	 * pointer and return.
+	 */
+	if (!vmlinux_set) {
+		tab->sets[hook][type] = add_set;
+		return 0;
+	}
+
+	/* In case of vmlinux sets, there may be more than one set being
+	 * registered per hook. To create a unified set, we allocate a new set
+	 * and concatenate all individual sets being registered. While each set
+	 * is individually sorted, they may become unsorted when concatenated,
+	 * hence re-sorting the final set again is required to make binary
+	 * searching the set using btf_id_set_contains function work.
+	 */
+	set_cnt = set ? set->cnt : 0;
+
+	if (set_cnt > U32_MAX - add_set->cnt) {
+		ret = -EOVERFLOW;
+		goto end;
+	}
+
+	if (set_cnt + add_set->cnt > BTF_KFUNC_SET_MAX_CNT) {
+		ret = -E2BIG;
+		goto end;
+	}
+
+	/* Grow set */
+	set = krealloc(tab->sets[hook][type],
+		       offsetof(struct btf_id_set, ids[set_cnt + add_set->cnt]),
+		       GFP_KERNEL | __GFP_NOWARN);
+	if (!set) {
+		ret = -ENOMEM;
+		goto end;
+	}
+
+	/* For newly allocated set, initialize set->cnt to 0 */
+	if (!tab->sets[hook][type])
+		set->cnt = 0;
+	tab->sets[hook][type] = set;
+
+	/* Concatenate the two sets */
+	memcpy(set->ids + set->cnt, add_set->ids, add_set->cnt * sizeof(set->ids[0]));
+	set->cnt += add_set->cnt;
+
+	sort(set->ids, set->cnt, sizeof(set->ids[0]), btf_id_cmp_func, NULL);
+
+	return 0;
+end:
+	btf_free_kfunc_set_tab(btf);
+	return ret;
 }
-EXPORT_SYMBOL_GPL(register_kfunc_btf_id_set);
 
-void unregister_kfunc_btf_id_set(struct kfunc_btf_id_list *l,
-				 struct kfunc_btf_id_set *s)
+static int btf_populate_kfunc_set(struct btf *btf, enum btf_kfunc_hook hook,
+				  const struct btf_kfunc_id_set *kset)
 {
-	mutex_lock(&l->mutex);
-	list_del_init(&s->list);
-	mutex_unlock(&l->mutex);
+	bool vmlinux_set = !btf_is_module(btf);
+	int type, ret;
+
+	for (type = 0; type < ARRAY_SIZE(kset->sets); type++) {
+		if (!kset->sets[type])
+			continue;
+
+		ret = __btf_populate_kfunc_set(btf, hook, type, kset->sets[type], vmlinux_set);
+		if (ret)
+			break;
+	}
+	return ret;
 }
-EXPORT_SYMBOL_GPL(unregister_kfunc_btf_id_set);
 
-bool bpf_check_mod_kfunc_call(struct kfunc_btf_id_list *klist, u32 kfunc_id,
-			      struct module *owner)
+static bool __btf_kfunc_id_set_contains(const struct btf *btf,
+					enum btf_kfunc_hook hook,
+					enum btf_kfunc_type type,
+					u32 kfunc_btf_id)
 {
-	struct kfunc_btf_id_set *s;
+	struct btf_id_set *set;
 
-	mutex_lock(&klist->mutex);
-	list_for_each_entry(s, &klist->list, list) {
-		if (s->owner == owner && btf_id_set_contains(s->set, kfunc_id)) {
-			mutex_unlock(&klist->mutex);
-			return true;
-		}
+	if (hook >= BTF_KFUNC_HOOK_MAX || type >= BTF_KFUNC_TYPE_MAX)
+		return false;
+	if (!btf->kfunc_set_tab)
+		return false;
+	set = btf->kfunc_set_tab->sets[hook][type];
+	if (!set)
+		return false;
+	return btf_id_set_contains(set, kfunc_btf_id);
+}
+
+static int bpf_prog_type_to_kfunc_hook(enum bpf_prog_type prog_type)
+{
+	switch (prog_type) {
+	case BPF_PROG_TYPE_XDP:
+		return BTF_KFUNC_HOOK_XDP;
+	case BPF_PROG_TYPE_SCHED_CLS:
+		return BTF_KFUNC_HOOK_TC;
+	case BPF_PROG_TYPE_STRUCT_OPS:
+		return BTF_KFUNC_HOOK_STRUCT_OPS;
+	default:
+		return BTF_KFUNC_HOOK_MAX;
 	}
-	mutex_unlock(&klist->mutex);
-	return false;
 }
 
-#define DEFINE_KFUNC_BTF_ID_LIST(name)                                         \
-	struct kfunc_btf_id_list name = { LIST_HEAD_INIT(name.list),           \
-					  __MUTEX_INITIALIZER(name.mutex) };   \
-	EXPORT_SYMBOL_GPL(name)
+/* Caution:
+ * Reference to the module (obtained using btf_try_get_module) corresponding to
+ * the struct btf *MUST* be held when calling this function from verifier
+ * context. This is usually true as we stash references in prog's kfunc_btf_tab;
+ * keeping the reference for the duration of the call provides the necessary
+ * protection for looking up a well-formed btf->kfunc_set_tab.
+ */
+bool btf_kfunc_id_set_contains(const struct btf *btf,
+			       enum bpf_prog_type prog_type,
+			       enum btf_kfunc_type type, u32 kfunc_btf_id)
+{
+	enum btf_kfunc_hook hook;
 
-DEFINE_KFUNC_BTF_ID_LIST(bpf_tcp_ca_kfunc_list);
-DEFINE_KFUNC_BTF_ID_LIST(prog_test_kfunc_list);
+	hook = bpf_prog_type_to_kfunc_hook(prog_type);
+	return __btf_kfunc_id_set_contains(btf, hook, type, kfunc_btf_id);
+}
 
-#endif
+/* This function must be invoked only from initcalls/module init functions */
+int register_btf_kfunc_id_set(enum bpf_prog_type prog_type,
+			      const struct btf_kfunc_id_set *kset)
+{
+	enum btf_kfunc_hook hook;
+	struct btf *btf;
+	int ret;
+
+	btf = btf_get_module_btf(kset->owner);
+	if (IS_ERR_OR_NULL(btf))
+		return btf ? PTR_ERR(btf) : -ENOENT;
+
+	hook = bpf_prog_type_to_kfunc_hook(prog_type);
+	ret = btf_populate_kfunc_set(btf, hook, kset);
+	/* reference is only taken for module BTF */
+	if (btf_is_module(btf))
+		btf_put(btf);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(register_btf_kfunc_id_set);
 
 int bpf_core_types_are_compat(const struct btf *local_btf, __u32 local_id,
 			      const struct btf *targ_btf, __u32 targ_id)