1 /*
2  * Copyright (c) 2017, Mellanox Technologies inc.  All rights reserved.
3  *
4  * This software is available to you under a choice of one of two
5  * licenses.  You may choose to be licensed under the terms of the GNU
6  * General Public License (GPL) Version 2, available from the file
7  * COPYING in the main directory of this source tree, or the
8  * OpenIB.org BSD license below:
9  *
10  *     Redistribution and use in source and binary forms, with or
11  *     without modification, are permitted provided that the following
12  *     conditions are met:
13  *
14  *      - Redistributions of source code must retain the above
15  *        copyright notice, this list of conditions and the following
16  *        disclaimer.
17  *
18  *      - Redistributions in binary form must reproduce the above
19  *        copyright notice, this list of conditions and the following
20  *        disclaimer in the documentation and/or other materials
21  *        provided with the distribution.
22  *
23  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
24  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
25  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
26  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
27  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
28  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
29  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
30  * SOFTWARE.
31  */
32 
33 #include <rdma/rdma_user_ioctl.h>
34 #include <rdma/uverbs_ioctl.h>
35 #include "rdma_core.h"
36 #include "uverbs.h"
37 
38 struct bundle_alloc_head {
39 	struct bundle_alloc_head *next;
40 	u8 data[];
41 };
42 
43 struct bundle_priv {
44 	/* Must be first */
45 	struct bundle_alloc_head alloc_head;
46 	struct bundle_alloc_head *allocated_mem;
47 	size_t internal_avail;
48 	size_t internal_used;
49 
50 	struct radix_tree_root *radix;
51 	const struct uverbs_api_ioctl_method *method_elm;
52 	void __rcu **radix_slots;
53 	unsigned long radix_slots_len;
54 	u32 method_key;
55 
56 	struct ib_uverbs_attr __user *user_attrs;
57 	struct ib_uverbs_attr *uattrs;
58 
59 	DECLARE_BITMAP(uobj_finalize, UVERBS_API_ATTR_BKEY_LEN);
60 	DECLARE_BITMAP(spec_finalize, UVERBS_API_ATTR_BKEY_LEN);
61 
62 	/*
63 	 * Must be last. bundle ends in a flex array which overlaps
64 	 * internal_buffer.
65 	 */
66 	struct uverbs_attr_bundle bundle;
67 	u64 internal_buffer[32];
68 };
69 
70 /*
71  * Each method has an absolute minimum amount of memory it needs to allocate,
72  * precompute that amount and determine if the onstack memory can be used or
73  * if allocation is need.
74  */
75 void uapi_compute_bundle_size(struct uverbs_api_ioctl_method *method_elm,
76 			      unsigned int num_attrs)
77 {
78 	struct bundle_priv *pbundle;
79 	size_t bundle_size =
80 		offsetof(struct bundle_priv, internal_buffer) +
81 		sizeof(*pbundle->bundle.attrs) * method_elm->key_bitmap_len +
82 		sizeof(*pbundle->uattrs) * num_attrs;
83 
84 	method_elm->use_stack = bundle_size <= sizeof(*pbundle);
85 	method_elm->bundle_size =
86 		ALIGN(bundle_size + 256, sizeof(*pbundle->internal_buffer));
87 
88 	/* Do not want order-2 allocations for this. */
89 	WARN_ON_ONCE(method_elm->bundle_size > PAGE_SIZE);
90 }
91 
92 /**
93  * uverbs_alloc() - Quickly allocate memory for use with a bundle
94  * @bundle: The bundle
95  * @size: Number of bytes to allocate
96  * @flags: Allocator flags
97  *
98  * The bundle allocator is intended for allocations that are connected with
99  * processing the system call related to the bundle. The allocated memory is
100  * always freed once the system call completes, and cannot be freed any other
101  * way.
102  *
103  * This tries to use a small pool of pre-allocated memory for performance.
104  */
105 __malloc void *_uverbs_alloc(struct uverbs_attr_bundle *bundle, size_t size,
106 			     gfp_t flags)
107 {
108 	struct bundle_priv *pbundle =
109 		container_of(bundle, struct bundle_priv, bundle);
110 	size_t new_used;
111 	void *res;
112 
113 	if (check_add_overflow(size, pbundle->internal_used, &new_used))
114 		return ERR_PTR(-EOVERFLOW);
115 
116 	if (new_used > pbundle->internal_avail) {
117 		struct bundle_alloc_head *buf;
118 
119 		buf = kvmalloc(struct_size(buf, data, size), flags);
120 		if (!buf)
121 			return ERR_PTR(-ENOMEM);
122 		buf->next = pbundle->allocated_mem;
123 		pbundle->allocated_mem = buf;
124 		return buf->data;
125 	}
126 
127 	res = (void *)pbundle->internal_buffer + pbundle->internal_used;
128 	pbundle->internal_used =
129 		ALIGN(new_used, sizeof(*pbundle->internal_buffer));
130 	if (flags & __GFP_ZERO)
131 		memset(res, 0, size);
132 	return res;
133 }
134 EXPORT_SYMBOL(_uverbs_alloc);
135 
136 static bool uverbs_is_attr_cleared(const struct ib_uverbs_attr *uattr,
137 				   u16 len)
138 {
139 	if (uattr->len > sizeof(((struct ib_uverbs_attr *)0)->data))
140 		return ib_is_buffer_cleared(u64_to_user_ptr(uattr->data) + len,
141 					    uattr->len - len);
142 
143 	return !memchr_inv((const void *)&uattr->data + len,
144 			   0, uattr->len - len);
145 }
146 
147 static int uverbs_process_idrs_array(struct bundle_priv *pbundle,
148 				     const struct uverbs_api_attr *attr_uapi,
149 				     struct uverbs_objs_arr_attr *attr,
150 				     struct ib_uverbs_attr *uattr,
151 				     u32 attr_bkey)
152 {
153 	const struct uverbs_attr_spec *spec = &attr_uapi->spec;
154 	size_t array_len;
155 	u32 *idr_vals;
156 	int ret = 0;
157 	size_t i;
158 
159 	if (uattr->attr_data.reserved)
160 		return -EINVAL;
161 
162 	if (uattr->len % sizeof(u32))
163 		return -EINVAL;
164 
165 	array_len = uattr->len / sizeof(u32);
166 	if (array_len < spec->u2.objs_arr.min_len ||
167 	    array_len > spec->u2.objs_arr.max_len)
168 		return -EINVAL;
169 
170 	attr->uobjects =
171 		uverbs_alloc(&pbundle->bundle,
172 			     array_size(array_len, sizeof(*attr->uobjects)));
173 	if (IS_ERR(attr->uobjects))
174 		return PTR_ERR(attr->uobjects);
175 
176 	/*
177 	 * Since idr is 4B and *uobjects is >= 4B, we can use attr->uobjects
178 	 * to store idrs array and avoid additional memory allocation. The
179 	 * idrs array is offset to the end of the uobjects array so we will be
180 	 * able to read idr and replace with a pointer.
181 	 */
182 	idr_vals = (u32 *)(attr->uobjects + array_len) - array_len;
183 
184 	if (uattr->len > sizeof(uattr->data)) {
185 		ret = copy_from_user(idr_vals, u64_to_user_ptr(uattr->data),
186 				     uattr->len);
187 		if (ret)
188 			return -EFAULT;
189 	} else {
190 		memcpy(idr_vals, &uattr->data, uattr->len);
191 	}
192 
193 	for (i = 0; i != array_len; i++) {
194 		attr->uobjects[i] = uverbs_get_uobject_from_file(
195 			spec->u2.objs_arr.obj_type, pbundle->bundle.ufile,
196 			spec->u2.objs_arr.access, idr_vals[i]);
197 		if (IS_ERR(attr->uobjects[i])) {
198 			ret = PTR_ERR(attr->uobjects[i]);
199 			break;
200 		}
201 	}
202 
203 	attr->len = i;
204 	__set_bit(attr_bkey, pbundle->spec_finalize);
205 	return ret;
206 }
207 
208 static int uverbs_free_idrs_array(const struct uverbs_api_attr *attr_uapi,
209 				  struct uverbs_objs_arr_attr *attr,
210 				  bool commit)
211 {
212 	const struct uverbs_attr_spec *spec = &attr_uapi->spec;
213 	int current_ret;
214 	int ret = 0;
215 	size_t i;
216 
217 	for (i = 0; i != attr->len; i++) {
218 		current_ret = uverbs_finalize_object(
219 			attr->uobjects[i], spec->u2.objs_arr.access, commit);
220 		if (!ret)
221 			ret = current_ret;
222 	}
223 
224 	return ret;
225 }
226 
227 static int uverbs_process_attr(struct bundle_priv *pbundle,
228 			       const struct uverbs_api_attr *attr_uapi,
229 			       struct ib_uverbs_attr *uattr, u32 attr_bkey)
230 {
231 	const struct uverbs_attr_spec *spec = &attr_uapi->spec;
232 	struct uverbs_attr *e = &pbundle->bundle.attrs[attr_bkey];
233 	const struct uverbs_attr_spec *val_spec = spec;
234 	struct uverbs_obj_attr *o_attr;
235 
236 	switch (spec->type) {
237 	case UVERBS_ATTR_TYPE_ENUM_IN:
238 		if (uattr->attr_data.enum_data.elem_id >= spec->u.enum_def.num_elems)
239 			return -EOPNOTSUPP;
240 
241 		if (uattr->attr_data.enum_data.reserved)
242 			return -EINVAL;
243 
244 		val_spec = &spec->u2.enum_def.ids[uattr->attr_data.enum_data.elem_id];
245 
246 		/* Currently we only support PTR_IN based enums */
247 		if (val_spec->type != UVERBS_ATTR_TYPE_PTR_IN)
248 			return -EOPNOTSUPP;
249 
250 		e->ptr_attr.enum_id = uattr->attr_data.enum_data.elem_id;
251 	/* fall through */
252 	case UVERBS_ATTR_TYPE_PTR_IN:
253 		/* Ensure that any data provided by userspace beyond the known
254 		 * struct is zero. Userspace that knows how to use some future
255 		 * longer struct will fail here if used with an old kernel and
256 		 * non-zero content, making ABI compat/discovery simpler.
257 		 */
258 		if (uattr->len > val_spec->u.ptr.len &&
259 		    val_spec->zero_trailing &&
260 		    !uverbs_is_attr_cleared(uattr, val_spec->u.ptr.len))
261 			return -EOPNOTSUPP;
262 
263 	/* fall through */
264 	case UVERBS_ATTR_TYPE_PTR_OUT:
265 		if (uattr->len < val_spec->u.ptr.min_len ||
266 		    (!val_spec->zero_trailing &&
267 		     uattr->len > val_spec->u.ptr.len))
268 			return -EINVAL;
269 
270 		if (spec->type != UVERBS_ATTR_TYPE_ENUM_IN &&
271 		    uattr->attr_data.reserved)
272 			return -EINVAL;
273 
274 		e->ptr_attr.uattr_idx = uattr - pbundle->uattrs;
275 		e->ptr_attr.len = uattr->len;
276 
277 		if (val_spec->alloc_and_copy && !uverbs_attr_ptr_is_inline(e)) {
278 			void *p;
279 
280 			p = uverbs_alloc(&pbundle->bundle, uattr->len);
281 			if (IS_ERR(p))
282 				return PTR_ERR(p);
283 
284 			e->ptr_attr.ptr = p;
285 
286 			if (copy_from_user(p, u64_to_user_ptr(uattr->data),
287 					   uattr->len))
288 				return -EFAULT;
289 		} else {
290 			e->ptr_attr.data = uattr->data;
291 		}
292 		break;
293 
294 	case UVERBS_ATTR_TYPE_IDR:
295 	case UVERBS_ATTR_TYPE_FD:
296 		if (uattr->attr_data.reserved)
297 			return -EINVAL;
298 
299 		if (uattr->len != 0)
300 			return -EINVAL;
301 
302 		o_attr = &e->obj_attr;
303 		o_attr->attr_elm = attr_uapi;
304 
305 		/*
306 		 * The type of uattr->data is u64 for UVERBS_ATTR_TYPE_IDR and
307 		 * s64 for UVERBS_ATTR_TYPE_FD. We can cast the u64 to s64
308 		 * here without caring about truncation as we know that the
309 		 * IDR implementation today rejects negative IDs
310 		 */
311 		o_attr->uobject = uverbs_get_uobject_from_file(
312 					spec->u.obj.obj_type,
313 					pbundle->bundle.ufile,
314 					spec->u.obj.access,
315 					uattr->data_s64);
316 		if (IS_ERR(o_attr->uobject))
317 			return PTR_ERR(o_attr->uobject);
318 		__set_bit(attr_bkey, pbundle->uobj_finalize);
319 
320 		if (spec->u.obj.access == UVERBS_ACCESS_NEW) {
321 			unsigned int uattr_idx = uattr - pbundle->uattrs;
322 			s64 id = o_attr->uobject->id;
323 
324 			/* Copy the allocated id to the user-space */
325 			if (put_user(id, &pbundle->user_attrs[uattr_idx].data))
326 				return -EFAULT;
327 		}
328 
329 		break;
330 
331 	case UVERBS_ATTR_TYPE_IDRS_ARRAY:
332 		return uverbs_process_idrs_array(pbundle, attr_uapi,
333 						 &e->objs_arr_attr, uattr,
334 						 attr_bkey);
335 	default:
336 		return -EOPNOTSUPP;
337 	}
338 
339 	return 0;
340 }
341 
342 /*
343  * We search the radix tree with the method prefix and now we want to fast
344  * search the suffix bits to get a particular attribute pointer. It is not
345  * totally clear to me if this breaks the radix tree encasulation or not, but
346  * it uses the iter data to determine if the method iter points at the same
347  * chunk that will store the attribute, if so it just derefs it directly. By
348  * construction in most kernel configs the method and attrs will all fit in a
349  * single radix chunk, so in most cases this will have no search. Other cases
350  * this falls back to a full search.
351  */
352 static void __rcu **uapi_get_attr_for_method(struct bundle_priv *pbundle,
353 					     u32 attr_key)
354 {
355 	void __rcu **slot;
356 
357 	if (likely(attr_key < pbundle->radix_slots_len)) {
358 		void *entry;
359 
360 		slot = pbundle->radix_slots + attr_key;
361 		entry = rcu_dereference_raw(*slot);
362 		if (likely(!radix_tree_is_internal_node(entry) && entry))
363 			return slot;
364 	}
365 
366 	return radix_tree_lookup_slot(pbundle->radix,
367 				      pbundle->method_key | attr_key);
368 }
369 
370 static int uverbs_set_attr(struct bundle_priv *pbundle,
371 			   struct ib_uverbs_attr *uattr)
372 {
373 	u32 attr_key = uapi_key_attr(uattr->attr_id);
374 	u32 attr_bkey = uapi_bkey_attr(attr_key);
375 	const struct uverbs_api_attr *attr;
376 	void __rcu **slot;
377 	int ret;
378 
379 	slot = uapi_get_attr_for_method(pbundle, attr_key);
380 	if (!slot) {
381 		/*
382 		 * Kernel does not support the attribute but user-space says it
383 		 * is mandatory
384 		 */
385 		if (uattr->flags & UVERBS_ATTR_F_MANDATORY)
386 			return -EPROTONOSUPPORT;
387 		return 0;
388 	}
389 	attr = rcu_dereference_protected(*slot, true);
390 
391 	/* Reject duplicate attributes from user-space */
392 	if (test_bit(attr_bkey, pbundle->bundle.attr_present))
393 		return -EINVAL;
394 
395 	ret = uverbs_process_attr(pbundle, attr, uattr, attr_bkey);
396 	if (ret)
397 		return ret;
398 
399 	__set_bit(attr_bkey, pbundle->bundle.attr_present);
400 
401 	return 0;
402 }
403 
404 static int ib_uverbs_run_method(struct bundle_priv *pbundle,
405 				unsigned int num_attrs)
406 {
407 	int (*handler)(struct uverbs_attr_bundle *attrs);
408 	size_t uattrs_size = array_size(sizeof(*pbundle->uattrs), num_attrs);
409 	unsigned int destroy_bkey = pbundle->method_elm->destroy_bkey;
410 	unsigned int i;
411 	int ret;
412 
413 	/* See uverbs_disassociate_api() */
414 	handler = srcu_dereference(
415 		pbundle->method_elm->handler,
416 		&pbundle->bundle.ufile->device->disassociate_srcu);
417 	if (!handler)
418 		return -EIO;
419 
420 	pbundle->uattrs = uverbs_alloc(&pbundle->bundle, uattrs_size);
421 	if (IS_ERR(pbundle->uattrs))
422 		return PTR_ERR(pbundle->uattrs);
423 	if (copy_from_user(pbundle->uattrs, pbundle->user_attrs, uattrs_size))
424 		return -EFAULT;
425 
426 	for (i = 0; i != num_attrs; i++) {
427 		ret = uverbs_set_attr(pbundle, &pbundle->uattrs[i]);
428 		if (unlikely(ret))
429 			return ret;
430 	}
431 
432 	/* User space did not provide all the mandatory attributes */
433 	if (unlikely(!bitmap_subset(pbundle->method_elm->attr_mandatory,
434 				    pbundle->bundle.attr_present,
435 				    pbundle->method_elm->key_bitmap_len)))
436 		return -EINVAL;
437 
438 	if (pbundle->method_elm->has_udata)
439 		uverbs_fill_udata(&pbundle->bundle,
440 				  &pbundle->bundle.driver_udata,
441 				  UVERBS_ATTR_UHW_IN, UVERBS_ATTR_UHW_OUT);
442 
443 	if (destroy_bkey != UVERBS_API_ATTR_BKEY_LEN) {
444 		struct uverbs_obj_attr *destroy_attr =
445 			&pbundle->bundle.attrs[destroy_bkey].obj_attr;
446 
447 		ret = uobj_destroy(destroy_attr->uobject);
448 		if (ret)
449 			return ret;
450 		__clear_bit(destroy_bkey, pbundle->uobj_finalize);
451 
452 		ret = handler(&pbundle->bundle);
453 		uobj_put_destroy(destroy_attr->uobject);
454 	} else {
455 		ret = handler(&pbundle->bundle);
456 	}
457 
458 	/*
459 	 * EPROTONOSUPPORT is ONLY to be returned if the ioctl framework can
460 	 * not invoke the method because the request is not supported.  No
461 	 * other cases should return this code.
462 	 */
463 	if (WARN_ON_ONCE(ret == -EPROTONOSUPPORT))
464 		return -EINVAL;
465 
466 	return ret;
467 }
468 
469 static int bundle_destroy(struct bundle_priv *pbundle, bool commit)
470 {
471 	unsigned int key_bitmap_len = pbundle->method_elm->key_bitmap_len;
472 	struct bundle_alloc_head *memblock;
473 	unsigned int i;
474 	int ret = 0;
475 
476 	/* fast path for simple uobjects */
477 	i = -1;
478 	while ((i = find_next_bit(pbundle->uobj_finalize, key_bitmap_len,
479 				  i + 1)) < key_bitmap_len) {
480 		struct uverbs_attr *attr = &pbundle->bundle.attrs[i];
481 		int current_ret;
482 
483 		current_ret = uverbs_finalize_object(
484 			attr->obj_attr.uobject,
485 			attr->obj_attr.attr_elm->spec.u.obj.access, commit);
486 		if (!ret)
487 			ret = current_ret;
488 	}
489 
490 	i = -1;
491 	while ((i = find_next_bit(pbundle->spec_finalize, key_bitmap_len,
492 				  i + 1)) < key_bitmap_len) {
493 		struct uverbs_attr *attr = &pbundle->bundle.attrs[i];
494 		const struct uverbs_api_attr *attr_uapi;
495 		void __rcu **slot;
496 		int current_ret;
497 
498 		slot = uapi_get_attr_for_method(
499 			pbundle,
500 			pbundle->method_key | uapi_bkey_to_key_attr(i));
501 		if (WARN_ON(!slot))
502 			continue;
503 
504 		attr_uapi = rcu_dereference_protected(*slot, true);
505 
506 		if (attr_uapi->spec.type == UVERBS_ATTR_TYPE_IDRS_ARRAY) {
507 			current_ret = uverbs_free_idrs_array(
508 				attr_uapi, &attr->objs_arr_attr, commit);
509 			if (!ret)
510 				ret = current_ret;
511 		}
512 	}
513 
514 	for (memblock = pbundle->allocated_mem; memblock;) {
515 		struct bundle_alloc_head *tmp = memblock;
516 
517 		memblock = memblock->next;
518 		kvfree(tmp);
519 	}
520 
521 	return ret;
522 }
523 
524 static int ib_uverbs_cmd_verbs(struct ib_uverbs_file *ufile,
525 			       struct ib_uverbs_ioctl_hdr *hdr,
526 			       struct ib_uverbs_attr __user *user_attrs)
527 {
528 	const struct uverbs_api_ioctl_method *method_elm;
529 	struct uverbs_api *uapi = ufile->device->uapi;
530 	struct radix_tree_iter attrs_iter;
531 	struct bundle_priv *pbundle;
532 	struct bundle_priv onstack;
533 	void __rcu **slot;
534 	int destroy_ret;
535 	int ret;
536 
537 	if (unlikely(hdr->driver_id != uapi->driver_id))
538 		return -EINVAL;
539 
540 	slot = radix_tree_iter_lookup(
541 		&uapi->radix, &attrs_iter,
542 		uapi_key_obj(hdr->object_id) |
543 			uapi_key_ioctl_method(hdr->method_id));
544 	if (unlikely(!slot))
545 		return -EPROTONOSUPPORT;
546 	method_elm = rcu_dereference_protected(*slot, true);
547 
548 	if (!method_elm->use_stack) {
549 		pbundle = kmalloc(method_elm->bundle_size, GFP_KERNEL);
550 		if (!pbundle)
551 			return -ENOMEM;
552 		pbundle->internal_avail =
553 			method_elm->bundle_size -
554 			offsetof(struct bundle_priv, internal_buffer);
555 		pbundle->alloc_head.next = NULL;
556 		pbundle->allocated_mem = &pbundle->alloc_head;
557 	} else {
558 		pbundle = &onstack;
559 		pbundle->internal_avail = sizeof(pbundle->internal_buffer);
560 		pbundle->allocated_mem = NULL;
561 	}
562 
563 	/* Space for the pbundle->bundle.attrs flex array */
564 	pbundle->method_elm = method_elm;
565 	pbundle->method_key = attrs_iter.index;
566 	pbundle->bundle.ufile = ufile;
567 	pbundle->radix = &uapi->radix;
568 	pbundle->radix_slots = slot;
569 	pbundle->radix_slots_len = radix_tree_chunk_size(&attrs_iter);
570 	pbundle->user_attrs = user_attrs;
571 
572 	pbundle->internal_used = ALIGN(pbundle->method_elm->key_bitmap_len *
573 					       sizeof(*pbundle->bundle.attrs),
574 				       sizeof(*pbundle->internal_buffer));
575 	memset(pbundle->bundle.attr_present, 0,
576 	       sizeof(pbundle->bundle.attr_present));
577 	memset(pbundle->uobj_finalize, 0, sizeof(pbundle->uobj_finalize));
578 	memset(pbundle->spec_finalize, 0, sizeof(pbundle->spec_finalize));
579 
580 	ret = ib_uverbs_run_method(pbundle, hdr->num_attrs);
581 	destroy_ret = bundle_destroy(pbundle, ret == 0);
582 	if (unlikely(destroy_ret && !ret))
583 		return destroy_ret;
584 
585 	return ret;
586 }
587 
588 long ib_uverbs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
589 {
590 	struct ib_uverbs_file *file = filp->private_data;
591 	struct ib_uverbs_ioctl_hdr __user *user_hdr =
592 		(struct ib_uverbs_ioctl_hdr __user *)arg;
593 	struct ib_uverbs_ioctl_hdr hdr;
594 	int srcu_key;
595 	int err;
596 
597 	if (unlikely(cmd != RDMA_VERBS_IOCTL))
598 		return -ENOIOCTLCMD;
599 
600 	err = copy_from_user(&hdr, user_hdr, sizeof(hdr));
601 	if (err)
602 		return -EFAULT;
603 
604 	if (hdr.length > PAGE_SIZE ||
605 	    hdr.length != struct_size(&hdr, attrs, hdr.num_attrs))
606 		return -EINVAL;
607 
608 	if (hdr.reserved1 || hdr.reserved2)
609 		return -EPROTONOSUPPORT;
610 
611 	srcu_key = srcu_read_lock(&file->device->disassociate_srcu);
612 	err = ib_uverbs_cmd_verbs(file, &hdr, user_hdr->attrs);
613 	srcu_read_unlock(&file->device->disassociate_srcu, srcu_key);
614 	return err;
615 }
616 
617 int uverbs_get_flags64(u64 *to, const struct uverbs_attr_bundle *attrs_bundle,
618 		       size_t idx, u64 allowed_bits)
619 {
620 	const struct uverbs_attr *attr;
621 	u64 flags;
622 
623 	attr = uverbs_attr_get(attrs_bundle, idx);
624 	/* Missing attribute means 0 flags */
625 	if (IS_ERR(attr)) {
626 		*to = 0;
627 		return 0;
628 	}
629 
630 	/*
631 	 * New userspace code should use 8 bytes to pass flags, but we
632 	 * transparently support old userspaces that were using 4 bytes as
633 	 * well.
634 	 */
635 	if (attr->ptr_attr.len == 8)
636 		flags = attr->ptr_attr.data;
637 	else if (attr->ptr_attr.len == 4)
638 		flags = *(u32 *)&attr->ptr_attr.data;
639 	else
640 		return -EINVAL;
641 
642 	if (flags & ~allowed_bits)
643 		return -EINVAL;
644 
645 	*to = flags;
646 	return 0;
647 }
648 EXPORT_SYMBOL(uverbs_get_flags64);
649 
650 int uverbs_get_flags32(u32 *to, const struct uverbs_attr_bundle *attrs_bundle,
651 		       size_t idx, u64 allowed_bits)
652 {
653 	u64 flags;
654 	int ret;
655 
656 	ret = uverbs_get_flags64(&flags, attrs_bundle, idx, allowed_bits);
657 	if (ret)
658 		return ret;
659 
660 	if (flags > U32_MAX)
661 		return -EINVAL;
662 	*to = flags;
663 
664 	return 0;
665 }
666 EXPORT_SYMBOL(uverbs_get_flags32);
667 
668 /*
669  * Fill a ib_udata struct (core or uhw) using the given attribute IDs.
670  * This is primarily used to convert the UVERBS_ATTR_UHW() into the
671  * ib_udata format used by the drivers.
672  */
673 void uverbs_fill_udata(struct uverbs_attr_bundle *bundle,
674 		       struct ib_udata *udata, unsigned int attr_in,
675 		       unsigned int attr_out)
676 {
677 	struct bundle_priv *pbundle =
678 		container_of(bundle, struct bundle_priv, bundle);
679 	const struct uverbs_attr *in =
680 		uverbs_attr_get(&pbundle->bundle, attr_in);
681 	const struct uverbs_attr *out =
682 		uverbs_attr_get(&pbundle->bundle, attr_out);
683 
684 	if (!IS_ERR(in)) {
685 		udata->inlen = in->ptr_attr.len;
686 		if (uverbs_attr_ptr_is_inline(in))
687 			udata->inbuf =
688 				&pbundle->user_attrs[in->ptr_attr.uattr_idx]
689 					 .data;
690 		else
691 			udata->inbuf = u64_to_user_ptr(in->ptr_attr.data);
692 	} else {
693 		udata->inbuf = NULL;
694 		udata->inlen = 0;
695 	}
696 
697 	if (!IS_ERR(out)) {
698 		udata->outbuf = u64_to_user_ptr(out->ptr_attr.data);
699 		udata->outlen = out->ptr_attr.len;
700 	} else {
701 		udata->outbuf = NULL;
702 		udata->outlen = 0;
703 	}
704 }
705 
706 int uverbs_copy_to(const struct uverbs_attr_bundle *bundle, size_t idx,
707 		   const void *from, size_t size)
708 {
709 	struct bundle_priv *pbundle =
710 		container_of(bundle, struct bundle_priv, bundle);
711 	const struct uverbs_attr *attr = uverbs_attr_get(bundle, idx);
712 	u16 flags;
713 	size_t min_size;
714 
715 	if (IS_ERR(attr))
716 		return PTR_ERR(attr);
717 
718 	min_size = min_t(size_t, attr->ptr_attr.len, size);
719 	if (copy_to_user(u64_to_user_ptr(attr->ptr_attr.data), from, min_size))
720 		return -EFAULT;
721 
722 	flags = pbundle->uattrs[attr->ptr_attr.uattr_idx].flags |
723 		UVERBS_ATTR_F_VALID_OUTPUT;
724 	if (put_user(flags,
725 		     &pbundle->user_attrs[attr->ptr_attr.uattr_idx].flags))
726 		return -EFAULT;
727 
728 	return 0;
729 }
730 EXPORT_SYMBOL(uverbs_copy_to);
731 
732 int _uverbs_get_const(s64 *to, const struct uverbs_attr_bundle *attrs_bundle,
733 		      size_t idx, s64 lower_bound, u64 upper_bound,
734 		      s64  *def_val)
735 {
736 	const struct uverbs_attr *attr;
737 
738 	attr = uverbs_attr_get(attrs_bundle, idx);
739 	if (IS_ERR(attr)) {
740 		if ((PTR_ERR(attr) != -ENOENT) || !def_val)
741 			return PTR_ERR(attr);
742 
743 		*to = *def_val;
744 	} else {
745 		*to = attr->ptr_attr.data;
746 	}
747 
748 	if (*to < lower_bound || (*to > 0 && (u64)*to > upper_bound))
749 		return -EINVAL;
750 
751 	return 0;
752 }
753 EXPORT_SYMBOL(_uverbs_get_const);
754 
755 int uverbs_copy_to_struct_or_zero(const struct uverbs_attr_bundle *bundle,
756 				  size_t idx, const void *from, size_t size)
757 {
758 	const struct uverbs_attr *attr = uverbs_attr_get(bundle, idx);
759 
760 	if (clear_user(u64_to_user_ptr(attr->ptr_attr.data),
761 		       attr->ptr_attr.len))
762 		return -EFAULT;
763 	return uverbs_copy_to(bundle, idx, from, size);
764 }
765