1 /*-
2 * Copyright (c) 2017 Netflix, Inc.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
14 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
16 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
17 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
18 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
19 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
20 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
21 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
22 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
23 * SUCH DAMAGE.
24 */
25
26 /*
27 * Routines to format EFI_DEVICE_PATHs from the UEFI standard. Much of
28 * this file is taken from EDK2 and rototilled.
29 */
30
31 #include <sys/cdefs.h>
32 #include <efivar.h>
33 #include <limits.h>
34 #include <stdio.h>
35 #include <string.h>
36 #include <sys/endian.h>
37
38 #include "efi-osdep.h"
39
40 #include "uefi-dplib.h"
41
42 /* XXX maybe I should include the entire DevicePathUtiltiies.c and ifdef out what we don't use */
43
44 /*
45 * Taken from MdePkg/Library/UefiDevicePathLib/DevicePathUtilities.c
46 * hash a11928f3310518ab1c6fd34e8d0fdbb72de9602c 2017-Mar-01
47 */
48
49 /** @file
50 Device Path services. The thing to remember is device paths are built out of
51 nodes. The device path is terminated by an end node that is length
52 sizeof(EFI_DEVICE_PATH_PROTOCOL). That would be why there is sizeof(EFI_DEVICE_PATH_PROTOCOL)
53 all over this file.
54
55 The only place where multi-instance device paths are supported is in
56 environment varibles. Multi-instance device paths should never be placed
57 on a Handle.
58
59 Copyright (c) 2006 - 2016, Intel Corporation. All rights reserved.<BR>
60 This program and the accompanying materials
61 are licensed and made available under the terms and conditions of the BSD License
62 which accompanies this distribution. The full text of the license may be found at
63 http://opensource.org/licenses/bsd-license.php.
64
65 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
66 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
67
68 **/
69
70 //
71 // Template for an end-of-device path node.
72 //
73 static CONST EFI_DEVICE_PATH_PROTOCOL mUefiDevicePathLibEndDevicePath = {
74 END_DEVICE_PATH_TYPE,
75 END_ENTIRE_DEVICE_PATH_SUBTYPE,
76 {
77 END_DEVICE_PATH_LENGTH,
78 0
79 }
80 };
81
82
83 /**
84 Returns the size of a device path in bytes.
85
86 This function returns the size, in bytes, of the device path data structure
87 specified by DevicePath including the end of device path node.
88 If DevicePath is NULL or invalid, then 0 is returned.
89
90 @param DevicePath A pointer to a device path data structure.
91
92 @retval 0 If DevicePath is NULL or invalid.
93 @retval Others The size of a device path in bytes.
94
95 **/
96 UINTN
97 EFIAPI
GetDevicePathSize(IN CONST EFI_DEVICE_PATH_PROTOCOL * DevicePath)98 GetDevicePathSize (
99 IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath
100 )
101 {
102 CONST EFI_DEVICE_PATH_PROTOCOL *Start;
103
104 if (DevicePath == NULL) {
105 return 0;
106 }
107
108 if (!IsDevicePathValid (DevicePath, 0)) {
109 return 0;
110 }
111
112 //
113 // Search for the end of the device path structure
114 //
115 Start = DevicePath;
116 while (!IsDevicePathEnd (DevicePath)) {
117 DevicePath = NextDevicePathNode (DevicePath);
118 }
119
120 //
121 // Compute the size and add back in the size of the end device path structure
122 //
123 return ((UINTN) DevicePath - (UINTN) Start) + DevicePathNodeLength (DevicePath);
124 }
125
126 /**
127 Determine whether a given device path is valid.
128 If DevicePath is NULL, then ASSERT().
129
130 @param DevicePath A pointer to a device path data structure.
131 @param MaxSize The maximum size of the device path data structure.
132
133 @retval TRUE DevicePath is valid.
134 @retval FALSE The length of any node in the DevicePath is less
135 than sizeof (EFI_DEVICE_PATH_PROTOCOL).
136 @retval FALSE If MaxSize is not zero, the size of the DevicePath
137 exceeds MaxSize.
138 @retval FALSE If PcdMaximumDevicePathNodeCount is not zero, the node
139 count of the DevicePath exceeds PcdMaximumDevicePathNodeCount.
140 **/
141 BOOLEAN
142 EFIAPI
IsDevicePathValid(IN CONST EFI_DEVICE_PATH_PROTOCOL * DevicePath,IN UINTN MaxSize)143 IsDevicePathValid (
144 IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath,
145 IN UINTN MaxSize
146 )
147 {
148 UINTN Count;
149 UINTN Size;
150 UINTN NodeLength;
151
152 ASSERT (DevicePath != NULL);
153
154 if (MaxSize == 0) {
155 MaxSize = MAX_UINTN;
156 }
157
158 //
159 // Validate the input size big enough to touch the first node.
160 //
161 if (MaxSize < sizeof (EFI_DEVICE_PATH_PROTOCOL)) {
162 return FALSE;
163 }
164
165 for (Count = 0, Size = 0; !IsDevicePathEnd (DevicePath); DevicePath = NextDevicePathNode (DevicePath)) {
166 NodeLength = DevicePathNodeLength (DevicePath);
167 if (NodeLength < sizeof (EFI_DEVICE_PATH_PROTOCOL)) {
168 return FALSE;
169 }
170
171 if (NodeLength > MAX_UINTN - Size) {
172 return FALSE;
173 }
174 Size += NodeLength;
175
176 //
177 // Validate next node before touch it.
178 //
179 if (Size > MaxSize - END_DEVICE_PATH_LENGTH ) {
180 return FALSE;
181 }
182
183 if (PcdGet32 (PcdMaximumDevicePathNodeCount) > 0) {
184 Count++;
185 if (Count >= PcdGet32 (PcdMaximumDevicePathNodeCount)) {
186 return FALSE;
187 }
188 }
189 }
190
191 //
192 // Only return TRUE when the End Device Path node is valid.
193 //
194 return (BOOLEAN) (DevicePathNodeLength (DevicePath) == END_DEVICE_PATH_LENGTH);
195 }
196
197 /**
198 Returns the Type field of a device path node.
199
200 Returns the Type field of the device path node specified by Node.
201
202 If Node is NULL, then ASSERT().
203
204 @param Node A pointer to a device path node data structure.
205
206 @return The Type field of the device path node specified by Node.
207
208 **/
209 UINT8
210 EFIAPI
DevicePathType(IN CONST VOID * Node)211 DevicePathType (
212 IN CONST VOID *Node
213 )
214 {
215 ASSERT (Node != NULL);
216 return ((const EFI_DEVICE_PATH_PROTOCOL *)(Node))->Type;
217 }
218
219
220 /**
221 Returns the SubType field of a device path node.
222
223 Returns the SubType field of the device path node specified by Node.
224
225 If Node is NULL, then ASSERT().
226
227 @param Node A pointer to a device path node data structure.
228
229 @return The SubType field of the device path node specified by Node.
230
231 **/
232 UINT8
233 EFIAPI
DevicePathSubType(IN CONST VOID * Node)234 DevicePathSubType (
235 IN CONST VOID *Node
236 )
237 {
238 ASSERT (Node != NULL);
239 return ((const EFI_DEVICE_PATH_PROTOCOL *)(Node))->SubType;
240 }
241
242 /**
243 Returns the 16-bit Length field of a device path node.
244
245 Returns the 16-bit Length field of the device path node specified by Node.
246 Node is not required to be aligned on a 16-bit boundary, so it is recommended
247 that a function such as ReadUnaligned16() be used to extract the contents of
248 the Length field.
249
250 If Node is NULL, then ASSERT().
251
252 @param Node A pointer to a device path node data structure.
253
254 @return The 16-bit Length field of the device path node specified by Node.
255
256 **/
257 UINTN
258 EFIAPI
DevicePathNodeLength(IN CONST VOID * Node)259 DevicePathNodeLength (
260 IN CONST VOID *Node
261 )
262 {
263 ASSERT (Node != NULL);
264 return ((const EFI_DEVICE_PATH_PROTOCOL *)Node)->Length[0] |
265 (((const EFI_DEVICE_PATH_PROTOCOL *)Node)->Length[1] << 8);
266 }
267
268 /**
269 Returns a pointer to the next node in a device path.
270
271 Returns a pointer to the device path node that follows the device path node
272 specified by Node.
273
274 If Node is NULL, then ASSERT().
275
276 @param Node A pointer to a device path node data structure.
277
278 @return a pointer to the device path node that follows the device path node
279 specified by Node.
280
281 **/
282 EFI_DEVICE_PATH_PROTOCOL *
283 EFIAPI
NextDevicePathNode(IN CONST VOID * Node)284 NextDevicePathNode (
285 IN CONST VOID *Node
286 )
287 {
288 ASSERT (Node != NULL);
289 return ((EFI_DEVICE_PATH_PROTOCOL *)(__DECONST(UINT8 *, Node) + DevicePathNodeLength(Node)));
290 }
291
292 /**
293 Determines if a device path node is an end node of a device path.
294 This includes nodes that are the end of a device path instance and nodes that
295 are the end of an entire device path.
296
297 Determines if the device path node specified by Node is an end node of a device path.
298 This includes nodes that are the end of a device path instance and nodes that are the
299 end of an entire device path. If Node represents an end node of a device path,
300 then TRUE is returned. Otherwise, FALSE is returned.
301
302 If Node is NULL, then ASSERT().
303
304 @param Node A pointer to a device path node data structure.
305
306 @retval TRUE The device path node specified by Node is an end node of a
307 device path.
308 @retval FALSE The device path node specified by Node is not an end node of
309 a device path.
310
311 **/
312 BOOLEAN
313 EFIAPI
IsDevicePathEndType(IN CONST VOID * Node)314 IsDevicePathEndType (
315 IN CONST VOID *Node
316 )
317 {
318 ASSERT (Node != NULL);
319 return (BOOLEAN) (DevicePathType (Node) == END_DEVICE_PATH_TYPE);
320 }
321
322 /**
323 Determines if a device path node is an end node of an entire device path.
324
325 Determines if a device path node specified by Node is an end node of an entire
326 device path. If Node represents the end of an entire device path, then TRUE is
327 returned. Otherwise, FALSE is returned.
328
329 If Node is NULL, then ASSERT().
330
331 @param Node A pointer to a device path node data structure.
332
333 @retval TRUE The device path node specified by Node is the end of an entire
334 device path.
335 @retval FALSE The device path node specified by Node is not the end of an
336 entire device path.
337
338 **/
339 BOOLEAN
340 EFIAPI
IsDevicePathEnd(IN CONST VOID * Node)341 IsDevicePathEnd (
342 IN CONST VOID *Node
343 )
344 {
345 ASSERT (Node != NULL);
346 return (BOOLEAN) (IsDevicePathEndType (Node) && DevicePathSubType(Node) == END_ENTIRE_DEVICE_PATH_SUBTYPE);
347 }
348
349 /**
350 Fills in all the fields of a device path node that is the end of an entire device path.
351
352 Fills in all the fields of a device path node specified by Node so Node represents
353 the end of an entire device path. The Type field of Node is set to
354 END_DEVICE_PATH_TYPE, the SubType field of Node is set to
355 END_ENTIRE_DEVICE_PATH_SUBTYPE, and the Length field of Node is set to
356 END_DEVICE_PATH_LENGTH. Node is not required to be aligned on a 16-bit boundary,
357 so it is recommended that a function such as WriteUnaligned16() be used to set
358 the contents of the Length field.
359
360 If Node is NULL, then ASSERT().
361
362 @param Node A pointer to a device path node data structure.
363
364 **/
365 VOID
366 EFIAPI
SetDevicePathEndNode(OUT VOID * Node)367 SetDevicePathEndNode (
368 OUT VOID *Node
369 )
370 {
371 ASSERT (Node != NULL);
372 memcpy (Node, &mUefiDevicePathLibEndDevicePath, sizeof (mUefiDevicePathLibEndDevicePath));
373 }
374
375 /**
376 Sets the length, in bytes, of a device path node.
377
378 Sets the length of the device path node specified by Node to the value specified
379 by NodeLength. NodeLength is returned. Node is not required to be aligned on
380 a 16-bit boundary, so it is recommended that a function such as WriteUnaligned16()
381 be used to set the contents of the Length field.
382
383 If Node is NULL, then ASSERT().
384 If NodeLength >= SIZE_64KB, then ASSERT().
385 If NodeLength < sizeof (EFI_DEVICE_PATH_PROTOCOL), then ASSERT().
386
387 @param Node A pointer to a device path node data structure.
388 @param Length The length, in bytes, of the device path node.
389
390 @return Length
391
392 **/
393 UINT16
394 EFIAPI
SetDevicePathNodeLength(IN OUT VOID * Node,IN UINTN Length)395 SetDevicePathNodeLength (
396 IN OUT VOID *Node,
397 IN UINTN Length
398 )
399 {
400 ASSERT (Node != NULL);
401 ASSERT ((Length >= sizeof (EFI_DEVICE_PATH_PROTOCOL)) && (Length < SIZE_64KB));
402 // return WriteUnaligned16 ((UINT16 *)&((EFI_DEVICE_PATH_PROTOCOL *)(Node))->Length[0], (UINT16)(Length));
403 le16enc(&((EFI_DEVICE_PATH_PROTOCOL *)(Node))->Length[0], (UINT16)(Length));
404 return Length;
405 }
406
407 /**
408 Creates a device node.
409
410 This function creates a new device node in a newly allocated buffer of size
411 NodeLength and initializes the device path node header with NodeType and NodeSubType.
412 The new device path node is returned.
413 If NodeLength is smaller than a device path header, then NULL is returned.
414 If there is not enough memory to allocate space for the new device path, then
415 NULL is returned.
416 The memory is allocated from EFI boot services memory. It is the responsibility
417 of the caller to free the memory allocated.
418
419 @param NodeType The device node type for the new device node.
420 @param NodeSubType The device node sub-type for the new device node.
421 @param NodeLength The length of the new device node.
422
423 @return The new device path.
424
425 **/
426 EFI_DEVICE_PATH_PROTOCOL *
427 EFIAPI
CreateDeviceNode(IN UINT8 NodeType,IN UINT8 NodeSubType,IN UINT16 NodeLength)428 CreateDeviceNode (
429 IN UINT8 NodeType,
430 IN UINT8 NodeSubType,
431 IN UINT16 NodeLength
432 )
433 {
434 EFI_DEVICE_PATH_PROTOCOL *DevicePath;
435
436 if (NodeLength < sizeof (EFI_DEVICE_PATH_PROTOCOL)) {
437 //
438 // NodeLength is less than the size of the header.
439 //
440 return NULL;
441 }
442
443 DevicePath = AllocateZeroPool (NodeLength);
444 if (DevicePath != NULL) {
445 DevicePath->Type = NodeType;
446 DevicePath->SubType = NodeSubType;
447 SetDevicePathNodeLength (DevicePath, NodeLength);
448 }
449
450 return DevicePath;
451 }
452
453 /**
454 Creates a new copy of an existing device path.
455
456 This function allocates space for a new copy of the device path specified by DevicePath.
457 If DevicePath is NULL, then NULL is returned. If the memory is successfully
458 allocated, then the contents of DevicePath are copied to the newly allocated
459 buffer, and a pointer to that buffer is returned. Otherwise, NULL is returned.
460 The memory for the new device path is allocated from EFI boot services memory.
461 It is the responsibility of the caller to free the memory allocated.
462
463 @param DevicePath A pointer to a device path data structure.
464
465 @retval NULL DevicePath is NULL or invalid.
466 @retval Others A pointer to the duplicated device path.
467
468 **/
469 EFI_DEVICE_PATH_PROTOCOL *
470 EFIAPI
DuplicateDevicePath(IN CONST EFI_DEVICE_PATH_PROTOCOL * DevicePath)471 DuplicateDevicePath (
472 IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath
473 )
474 {
475 UINTN Size;
476
477 //
478 // Compute the size
479 //
480 Size = GetDevicePathSize (DevicePath);
481 if (Size == 0) {
482 return NULL;
483 }
484
485 //
486 // Allocate space for duplicate device path
487 //
488
489 return AllocateCopyPool (Size, DevicePath);
490 }
491
492 /**
493 Creates a new device path by appending a second device path to a first device path.
494
495 This function creates a new device path by appending a copy of SecondDevicePath
496 to a copy of FirstDevicePath in a newly allocated buffer. Only the end-of-device-path
497 device node from SecondDevicePath is retained. The newly created device path is
498 returned. If FirstDevicePath is NULL, then it is ignored, and a duplicate of
499 SecondDevicePath is returned. If SecondDevicePath is NULL, then it is ignored,
500 and a duplicate of FirstDevicePath is returned. If both FirstDevicePath and
501 SecondDevicePath are NULL, then a copy of an end-of-device-path is returned.
502
503 If there is not enough memory for the newly allocated buffer, then NULL is returned.
504 The memory for the new device path is allocated from EFI boot services memory.
505 It is the responsibility of the caller to free the memory allocated.
506
507 @param FirstDevicePath A pointer to a device path data structure.
508 @param SecondDevicePath A pointer to a device path data structure.
509
510 @retval NULL If there is not enough memory for the newly allocated buffer.
511 @retval NULL If FirstDevicePath or SecondDevicePath is invalid.
512 @retval Others A pointer to the new device path if success.
513 Or a copy an end-of-device-path if both FirstDevicePath and SecondDevicePath are NULL.
514
515 **/
516 EFI_DEVICE_PATH_PROTOCOL *
517 EFIAPI
AppendDevicePath(IN CONST EFI_DEVICE_PATH_PROTOCOL * FirstDevicePath,OPTIONAL IN CONST EFI_DEVICE_PATH_PROTOCOL * SecondDevicePath OPTIONAL)518 AppendDevicePath (
519 IN CONST EFI_DEVICE_PATH_PROTOCOL *FirstDevicePath, OPTIONAL
520 IN CONST EFI_DEVICE_PATH_PROTOCOL *SecondDevicePath OPTIONAL
521 )
522 {
523 UINTN Size;
524 UINTN Size1;
525 UINTN Size2;
526 EFI_DEVICE_PATH_PROTOCOL *NewDevicePath;
527 EFI_DEVICE_PATH_PROTOCOL *DevicePath2;
528
529 //
530 // If there's only 1 path, just duplicate it.
531 //
532 if (FirstDevicePath == NULL) {
533 return DuplicateDevicePath ((SecondDevicePath != NULL) ? SecondDevicePath : &mUefiDevicePathLibEndDevicePath);
534 }
535
536 if (SecondDevicePath == NULL) {
537 return DuplicateDevicePath (FirstDevicePath);
538 }
539
540 if (!IsDevicePathValid (FirstDevicePath, 0) || !IsDevicePathValid (SecondDevicePath, 0)) {
541 return NULL;
542 }
543
544 //
545 // Allocate space for the combined device path. It only has one end node of
546 // length EFI_DEVICE_PATH_PROTOCOL.
547 //
548 Size1 = GetDevicePathSize (FirstDevicePath);
549 Size2 = GetDevicePathSize (SecondDevicePath);
550 Size = Size1 + Size2 - END_DEVICE_PATH_LENGTH;
551
552 NewDevicePath = AllocatePool (Size);
553
554 if (NewDevicePath != NULL) {
555 NewDevicePath = CopyMem (NewDevicePath, FirstDevicePath, Size1);
556 //
557 // Over write FirstDevicePath EndNode and do the copy
558 //
559 DevicePath2 = (EFI_DEVICE_PATH_PROTOCOL *) ((CHAR8 *) NewDevicePath +
560 (Size1 - END_DEVICE_PATH_LENGTH));
561 CopyMem (DevicePath2, SecondDevicePath, Size2);
562 }
563
564 return NewDevicePath;
565 }
566
567 /**
568 Creates a new path by appending the device node to the device path.
569
570 This function creates a new device path by appending a copy of the device node
571 specified by DevicePathNode to a copy of the device path specified by DevicePath
572 in an allocated buffer. The end-of-device-path device node is moved after the
573 end of the appended device node.
574 If DevicePathNode is NULL then a copy of DevicePath is returned.
575 If DevicePath is NULL then a copy of DevicePathNode, followed by an end-of-device
576 path device node is returned.
577 If both DevicePathNode and DevicePath are NULL then a copy of an end-of-device-path
578 device node is returned.
579 If there is not enough memory to allocate space for the new device path, then
580 NULL is returned.
581 The memory is allocated from EFI boot services memory. It is the responsibility
582 of the caller to free the memory allocated.
583
584 @param DevicePath A pointer to a device path data structure.
585 @param DevicePathNode A pointer to a single device path node.
586
587 @retval NULL If there is not enough memory for the new device path.
588 @retval Others A pointer to the new device path if success.
589 A copy of DevicePathNode followed by an end-of-device-path node
590 if both FirstDevicePath and SecondDevicePath are NULL.
591 A copy of an end-of-device-path node if both FirstDevicePath
592 and SecondDevicePath are NULL.
593
594 **/
595 EFI_DEVICE_PATH_PROTOCOL *
596 EFIAPI
AppendDevicePathNode(IN CONST EFI_DEVICE_PATH_PROTOCOL * DevicePath,OPTIONAL IN CONST EFI_DEVICE_PATH_PROTOCOL * DevicePathNode OPTIONAL)597 AppendDevicePathNode (
598 IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath, OPTIONAL
599 IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePathNode OPTIONAL
600 )
601 {
602 EFI_DEVICE_PATH_PROTOCOL *TempDevicePath;
603 EFI_DEVICE_PATH_PROTOCOL *NextNode;
604 EFI_DEVICE_PATH_PROTOCOL *NewDevicePath;
605 UINTN NodeLength;
606
607 if (DevicePathNode == NULL) {
608 return DuplicateDevicePath ((DevicePath != NULL) ? DevicePath : &mUefiDevicePathLibEndDevicePath);
609 }
610 //
611 // Build a Node that has a terminator on it
612 //
613 NodeLength = DevicePathNodeLength (DevicePathNode);
614
615 TempDevicePath = AllocatePool (NodeLength + END_DEVICE_PATH_LENGTH);
616 if (TempDevicePath == NULL) {
617 return NULL;
618 }
619 TempDevicePath = CopyMem (TempDevicePath, DevicePathNode, NodeLength);
620 //
621 // Add and end device path node to convert Node to device path
622 //
623 NextNode = NextDevicePathNode (TempDevicePath);
624 SetDevicePathEndNode (NextNode);
625 //
626 // Append device paths
627 //
628 NewDevicePath = AppendDevicePath (DevicePath, TempDevicePath);
629
630 FreePool (TempDevicePath);
631
632 return NewDevicePath;
633 }
634