1 // SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB
2 /*
3  * Copyright (c) 2017, Mellanox Technologies inc.  All rights reserved.
4  */
5 #include <rdma/uverbs_ioctl.h>
6 #include <rdma/rdma_user_ioctl.h>
7 #include <linux/bitops.h>
8 #include "rdma_core.h"
9 #include "uverbs.h"
10 
11 static void *uapi_add_elm(struct uverbs_api *uapi, u32 key, size_t alloc_size)
12 {
13 	void *elm;
14 	int rc;
15 
16 	if (key == UVERBS_API_KEY_ERR)
17 		return ERR_PTR(-EOVERFLOW);
18 
19 	elm = kzalloc(alloc_size, GFP_KERNEL);
20 	rc = radix_tree_insert(&uapi->radix, key, elm);
21 	if (rc) {
22 		kfree(elm);
23 		return ERR_PTR(rc);
24 	}
25 
26 	return elm;
27 }
28 
29 static int uapi_merge_method(struct uverbs_api *uapi,
30 			     struct uverbs_api_object *obj_elm, u32 obj_key,
31 			     const struct uverbs_method_def *method,
32 			     bool is_driver)
33 {
34 	u32 method_key = obj_key | uapi_key_ioctl_method(method->id);
35 	struct uverbs_api_ioctl_method *method_elm;
36 	unsigned int i;
37 
38 	if (!method->attrs)
39 		return 0;
40 
41 	method_elm = uapi_add_elm(uapi, method_key, sizeof(*method_elm));
42 	if (IS_ERR(method_elm)) {
43 		if (method_elm != ERR_PTR(-EEXIST))
44 			return PTR_ERR(method_elm);
45 
46 		/*
47 		 * This occurs when a driver uses ADD_UVERBS_ATTRIBUTES_SIMPLE
48 		 */
49 		if (WARN_ON(method->handler))
50 			return -EINVAL;
51 		method_elm = radix_tree_lookup(&uapi->radix, method_key);
52 		if (WARN_ON(!method_elm))
53 			return -EINVAL;
54 	} else {
55 		WARN_ON(!method->handler);
56 		rcu_assign_pointer(method_elm->handler, method->handler);
57 		if (method->handler != uverbs_destroy_def_handler)
58 			method_elm->driver_method = is_driver;
59 	}
60 
61 	for (i = 0; i != method->num_attrs; i++) {
62 		const struct uverbs_attr_def *attr = (*method->attrs)[i];
63 		struct uverbs_api_attr *attr_slot;
64 
65 		if (!attr)
66 			continue;
67 
68 		/*
69 		 * ENUM_IN contains the 'ids' pointer to the driver's .rodata,
70 		 * so if it is specified by a driver then it always makes this
71 		 * into a driver method.
72 		 */
73 		if (attr->attr.type == UVERBS_ATTR_TYPE_ENUM_IN)
74 			method_elm->driver_method |= is_driver;
75 
76 		attr_slot =
77 			uapi_add_elm(uapi, method_key | uapi_key_attr(attr->id),
78 				     sizeof(*attr_slot));
79 		/* Attributes are not allowed to be modified by drivers */
80 		if (IS_ERR(attr_slot))
81 			return PTR_ERR(attr_slot);
82 
83 		attr_slot->spec = attr->attr;
84 	}
85 
86 	return 0;
87 }
88 
89 static int uapi_merge_tree(struct uverbs_api *uapi,
90 			   const struct uverbs_object_tree_def *tree,
91 			   bool is_driver)
92 {
93 	unsigned int i, j;
94 	int rc;
95 
96 	if (!tree->objects)
97 		return 0;
98 
99 	for (i = 0; i != tree->num_objects; i++) {
100 		const struct uverbs_object_def *obj = (*tree->objects)[i];
101 		struct uverbs_api_object *obj_elm;
102 		u32 obj_key;
103 
104 		if (!obj)
105 			continue;
106 
107 		obj_key = uapi_key_obj(obj->id);
108 		obj_elm = uapi_add_elm(uapi, obj_key, sizeof(*obj_elm));
109 		if (IS_ERR(obj_elm)) {
110 			if (obj_elm != ERR_PTR(-EEXIST))
111 				return PTR_ERR(obj_elm);
112 
113 			/* This occurs when a driver uses ADD_UVERBS_METHODS */
114 			if (WARN_ON(obj->type_attrs))
115 				return -EINVAL;
116 			obj_elm = radix_tree_lookup(&uapi->radix, obj_key);
117 			if (WARN_ON(!obj_elm))
118 				return -EINVAL;
119 		} else {
120 			obj_elm->type_attrs = obj->type_attrs;
121 			if (obj->type_attrs) {
122 				obj_elm->type_class =
123 					obj->type_attrs->type_class;
124 				/*
125 				 * Today drivers are only permitted to use
126 				 * idr_class types. They cannot use FD types
127 				 * because we currently have no way to revoke
128 				 * the fops pointer after device
129 				 * disassociation.
130 				 */
131 				if (WARN_ON(is_driver &&
132 					    obj->type_attrs->type_class !=
133 						    &uverbs_idr_class))
134 					return -EINVAL;
135 			}
136 		}
137 
138 		if (!obj->methods)
139 			continue;
140 
141 		for (j = 0; j != obj->num_methods; j++) {
142 			const struct uverbs_method_def *method =
143 				(*obj->methods)[j];
144 			if (!method)
145 				continue;
146 
147 			rc = uapi_merge_method(uapi, obj_elm, obj_key, method,
148 					       is_driver);
149 			if (rc)
150 				return rc;
151 		}
152 	}
153 
154 	return 0;
155 }
156 
157 static int
158 uapi_finalize_ioctl_method(struct uverbs_api *uapi,
159 			   struct uverbs_api_ioctl_method *method_elm,
160 			   u32 method_key)
161 {
162 	struct radix_tree_iter iter;
163 	unsigned int num_attrs = 0;
164 	unsigned int max_bkey = 0;
165 	bool single_uobj = false;
166 	void __rcu **slot;
167 
168 	method_elm->destroy_bkey = UVERBS_API_ATTR_BKEY_LEN;
169 	radix_tree_for_each_slot (slot, &uapi->radix, &iter,
170 				  uapi_key_attrs_start(method_key)) {
171 		struct uverbs_api_attr *elm =
172 			rcu_dereference_protected(*slot, true);
173 		u32 attr_key = iter.index & UVERBS_API_ATTR_KEY_MASK;
174 		u32 attr_bkey = uapi_bkey_attr(attr_key);
175 		u8 type = elm->spec.type;
176 
177 		if (uapi_key_attr_to_method(iter.index) !=
178 		    uapi_key_attr_to_method(method_key))
179 			break;
180 
181 		if (elm->spec.mandatory)
182 			__set_bit(attr_bkey, method_elm->attr_mandatory);
183 
184 		if (type == UVERBS_ATTR_TYPE_IDR ||
185 		    type == UVERBS_ATTR_TYPE_FD) {
186 			u8 access = elm->spec.u.obj.access;
187 
188 			/*
189 			 * Verbs specs may only have one NEW/DESTROY, we don't
190 			 * have the infrastructure to abort multiple NEW's or
191 			 * cope with multiple DESTROY failure.
192 			 */
193 			if (access == UVERBS_ACCESS_NEW ||
194 			    access == UVERBS_ACCESS_DESTROY) {
195 				if (WARN_ON(single_uobj))
196 					return -EINVAL;
197 
198 				single_uobj = true;
199 				if (WARN_ON(!elm->spec.mandatory))
200 					return -EINVAL;
201 			}
202 
203 			if (access == UVERBS_ACCESS_DESTROY)
204 				method_elm->destroy_bkey = attr_bkey;
205 		}
206 
207 		max_bkey = max(max_bkey, attr_bkey);
208 		num_attrs++;
209 	}
210 
211 	method_elm->key_bitmap_len = max_bkey + 1;
212 	WARN_ON(method_elm->key_bitmap_len > UVERBS_API_ATTR_BKEY_LEN);
213 
214 	uapi_compute_bundle_size(method_elm, num_attrs);
215 	return 0;
216 }
217 
218 static int uapi_finalize(struct uverbs_api *uapi)
219 {
220 	struct radix_tree_iter iter;
221 	void __rcu **slot;
222 	int rc;
223 
224 	radix_tree_for_each_slot (slot, &uapi->radix, &iter, 0) {
225 		struct uverbs_api_ioctl_method *method_elm =
226 			rcu_dereference_protected(*slot, true);
227 
228 		if (uapi_key_is_ioctl_method(iter.index)) {
229 			rc = uapi_finalize_ioctl_method(uapi, method_elm,
230 							iter.index);
231 			if (rc)
232 				return rc;
233 		}
234 	}
235 
236 	return 0;
237 }
238 
239 void uverbs_destroy_api(struct uverbs_api *uapi)
240 {
241 	struct radix_tree_iter iter;
242 	void __rcu **slot;
243 
244 	if (!uapi)
245 		return;
246 
247 	radix_tree_for_each_slot (slot, &uapi->radix, &iter, 0) {
248 		kfree(rcu_dereference_protected(*slot, true));
249 		radix_tree_iter_delete(&uapi->radix, &iter, slot);
250 	}
251 }
252 
253 struct uverbs_api *uverbs_alloc_api(
254 	const struct uverbs_object_tree_def *const *driver_specs,
255 	enum rdma_driver_id driver_id)
256 {
257 	struct uverbs_api *uapi;
258 	int rc;
259 
260 	uapi = kzalloc(sizeof(*uapi), GFP_KERNEL);
261 	if (!uapi)
262 		return ERR_PTR(-ENOMEM);
263 
264 	INIT_RADIX_TREE(&uapi->radix, GFP_KERNEL);
265 	uapi->driver_id = driver_id;
266 
267 	rc = uapi_merge_tree(uapi, uverbs_default_get_objects(), false);
268 	if (rc)
269 		goto err;
270 
271 	for (; driver_specs && *driver_specs; driver_specs++) {
272 		rc = uapi_merge_tree(uapi, *driver_specs, true);
273 		if (rc)
274 			goto err;
275 	}
276 
277 	rc = uapi_finalize(uapi);
278 	if (rc)
279 		goto err;
280 
281 	return uapi;
282 err:
283 	if (rc != -ENOMEM)
284 		pr_err("Setup of uverbs_api failed, kernel parsing tree description is not valid (%d)??\n",
285 		       rc);
286 
287 	uverbs_destroy_api(uapi);
288 	return ERR_PTR(rc);
289 }
290 
291 /*
292  * The pre version is done before destroying the HW objects, it only blocks
293  * off method access. All methods that require the ib_dev or the module data
294  * must test one of these assignments prior to continuing.
295  */
296 void uverbs_disassociate_api_pre(struct ib_uverbs_device *uverbs_dev)
297 {
298 	struct uverbs_api *uapi = uverbs_dev->uapi;
299 	struct radix_tree_iter iter;
300 	void __rcu **slot;
301 
302 	rcu_assign_pointer(uverbs_dev->ib_dev, NULL);
303 
304 	radix_tree_for_each_slot (slot, &uapi->radix, &iter, 0) {
305 		if (uapi_key_is_ioctl_method(iter.index)) {
306 			struct uverbs_api_ioctl_method *method_elm =
307 				rcu_dereference_protected(*slot, true);
308 
309 			if (method_elm->driver_method)
310 				rcu_assign_pointer(method_elm->handler, NULL);
311 		}
312 	}
313 
314 	synchronize_srcu(&uverbs_dev->disassociate_srcu);
315 }
316 
317 /*
318  * Called when a driver disassociates from the ib_uverbs_device. The
319  * assumption is that the driver module will unload after. Replace everything
320  * related to the driver with NULL as a safety measure.
321  */
322 void uverbs_disassociate_api(struct uverbs_api *uapi)
323 {
324 	struct radix_tree_iter iter;
325 	void __rcu **slot;
326 
327 	radix_tree_for_each_slot (slot, &uapi->radix, &iter, 0) {
328 		if (uapi_key_is_object(iter.index)) {
329 			struct uverbs_api_object *object_elm =
330 				rcu_dereference_protected(*slot, true);
331 
332 			/*
333 			 * Some type_attrs are in the driver module. We don't
334 			 * bother to keep track of which since there should be
335 			 * no use of this after disassociate.
336 			 */
337 			object_elm->type_attrs = NULL;
338 		} else if (uapi_key_is_attr(iter.index)) {
339 			struct uverbs_api_attr *elm =
340 				rcu_dereference_protected(*slot, true);
341 
342 			if (elm->spec.type == UVERBS_ATTR_TYPE_ENUM_IN)
343 				elm->spec.u2.enum_def.ids = NULL;
344 		}
345 	}
346 }
347