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 * $FreeBSD: head/lib/libefivar/uefi-dputil.c 343755 2019-02-04 21:28:25Z imp $
26 */
27
28 /*
29 * Routines to format EFI_DEVICE_PATHs from the UEFI standard. Much of
30 * this file is taken from EDK2 and rototilled.
31 */
32
33 #include <efivar.h>
34 #include <limits.h>
35 #include <stdio.h>
36 #include <string.h>
37 #include <sys/endian.h>
38
39 #include "efi-osdep.h"
40
41 #include "uefi-dplib.h"
42
43 /* XXX maybe I should include the entire DevicePathUtilities.c and ifdef out what we don't use */
44
45 /*
46 * Taken from MdePkg/Library/UefiDevicePathLib/DevicePathUtilities.c
47 * hash a11928f3310518ab1c6fd34e8d0fdbb72de9602c 2017-Mar-01
48 */
49
50 /** @file
51 Device Path services. The thing to remember is device paths are built out of
52 nodes. The device path is terminated by an end node that is length
53 sizeof(EFI_DEVICE_PATH_PROTOCOL). That would be why there is sizeof(EFI_DEVICE_PATH_PROTOCOL)
54 all over this file.
55
56 The only place where multi-instance device paths are supported is in
57 environment varibles. Multi-instance device paths should never be placed
58 on a Handle.
59
60 Copyright (c) 2006 - 2016, Intel Corporation. All rights reserved.<BR>
61 This program and the accompanying materials
62 are licensed and made available under the terms and conditions of the BSD License
63 which accompanies this distribution. The full text of the license may be found at
64 http://opensource.org/licenses/bsd-license.php.
65
66 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
67 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
68
69 **/
70
71 //
72 // Template for an end-of-device path node.
73 //
74 static CONST EFI_DEVICE_PATH_PROTOCOL mUefiDevicePathLibEndDevicePath = {
75 END_DEVICE_PATH_TYPE,
76 END_ENTIRE_DEVICE_PATH_SUBTYPE,
77 {
78 END_DEVICE_PATH_LENGTH,
79 0
80 }
81 };
82
83
84 /**
85 Returns the size of a device path in bytes.
86
87 This function returns the size, in bytes, of the device path data structure
88 specified by DevicePath including the end of device path node.
89 If DevicePath is NULL or invalid, then 0 is returned.
90
91 @param DevicePath A pointer to a device path data structure.
92
93 @retval 0 If DevicePath is NULL or invalid.
94 @retval Others The size of a device path in bytes.
95
96 **/
97 UINTN
98 EFIAPI
GetDevicePathSize(IN CONST EFI_DEVICE_PATH_PROTOCOL * DevicePath)99 GetDevicePathSize (
100 IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath
101 )
102 {
103 CONST EFI_DEVICE_PATH_PROTOCOL *Start;
104
105 if (DevicePath == NULL) {
106 return 0;
107 }
108
109 if (!IsDevicePathValid (DevicePath, 0)) {
110 return 0;
111 }
112
113 //
114 // Search for the end of the device path structure
115 //
116 Start = DevicePath;
117 while (!IsDevicePathEnd (DevicePath)) {
118 DevicePath = NextDevicePathNode (DevicePath);
119 }
120
121 //
122 // Compute the size and add back in the size of the end device path structure
123 //
124 return ((UINTN) DevicePath - (UINTN) Start) + DevicePathNodeLength (DevicePath);
125 }
126
127 /**
128 Determine whether a given device path is valid.
129 If DevicePath is NULL, then ASSERT().
130
131 @param DevicePath A pointer to a device path data structure.
132 @param MaxSize The maximum size of the device path data structure.
133
134 @retval TRUE DevicePath is valid.
135 @retval FALSE The length of any node in the DevicePath is less
136 than sizeof (EFI_DEVICE_PATH_PROTOCOL).
137 @retval FALSE If MaxSize is not zero, the size of the DevicePath
138 exceeds MaxSize.
139 @retval FALSE If PcdMaximumDevicePathNodeCount is not zero, the node
140 count of the DevicePath exceeds PcdMaximumDevicePathNodeCount.
141 **/
142 BOOLEAN
143 EFIAPI
IsDevicePathValid(IN CONST EFI_DEVICE_PATH_PROTOCOL * DevicePath,IN UINTN MaxSize)144 IsDevicePathValid (
145 IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath,
146 IN UINTN MaxSize
147 )
148 {
149 UINTN Count;
150 UINTN Size;
151 UINTN NodeLength;
152
153 ASSERT (DevicePath != NULL);
154
155 if (MaxSize == 0) {
156 MaxSize = MAX_UINTN;
157 }
158
159 //
160 // Validate the input size big enough to touch the first node.
161 //
162 if (MaxSize < sizeof (EFI_DEVICE_PATH_PROTOCOL)) {
163 return FALSE;
164 }
165
166 for (Count = 0, Size = 0; !IsDevicePathEnd (DevicePath); DevicePath = NextDevicePathNode (DevicePath)) {
167 NodeLength = DevicePathNodeLength (DevicePath);
168 if (NodeLength < sizeof (EFI_DEVICE_PATH_PROTOCOL)) {
169 return FALSE;
170 }
171
172 if (NodeLength > MAX_UINTN - Size) {
173 return FALSE;
174 }
175 Size += NodeLength;
176
177 //
178 // Validate next node before touch it.
179 //
180 if (Size > MaxSize - END_DEVICE_PATH_LENGTH ) {
181 return FALSE;
182 }
183
184 if (PcdGet32 (PcdMaximumDevicePathNodeCount) > 0) {
185 Count++;
186 if (Count >= PcdGet32 (PcdMaximumDevicePathNodeCount)) {
187 return FALSE;
188 }
189 }
190 }
191
192 //
193 // Only return TRUE when the End Device Path node is valid.
194 //
195 return (BOOLEAN) (DevicePathNodeLength (DevicePath) == END_DEVICE_PATH_LENGTH);
196 }
197
198 /**
199 Returns the Type field of a device path node.
200
201 Returns the Type field of the device path node specified by Node.
202
203 If Node is NULL, then ASSERT().
204
205 @param Node A pointer to a device path node data structure.
206
207 @return The Type field of the device path node specified by Node.
208
209 **/
210 UINT8
211 EFIAPI
DevicePathType(IN CONST VOID * Node)212 DevicePathType (
213 IN CONST VOID *Node
214 )
215 {
216 ASSERT (Node != NULL);
217 return ((const EFI_DEVICE_PATH_PROTOCOL *)(Node))->Type;
218 }
219
220
221 /**
222 Returns the SubType field of a device path node.
223
224 Returns the SubType field of the device path node specified by Node.
225
226 If Node is NULL, then ASSERT().
227
228 @param Node A pointer to a device path node data structure.
229
230 @return The SubType field of the device path node specified by Node.
231
232 **/
233 UINT8
234 EFIAPI
DevicePathSubType(IN CONST VOID * Node)235 DevicePathSubType (
236 IN CONST VOID *Node
237 )
238 {
239 ASSERT (Node != NULL);
240 return ((const EFI_DEVICE_PATH_PROTOCOL *)(Node))->SubType;
241 }
242
243 /**
244 Returns the 16-bit Length field of a device path node.
245
246 Returns the 16-bit Length field of the device path node specified by Node.
247 Node is not required to be aligned on a 16-bit boundary, so it is recommended
248 that a function such as ReadUnaligned16() be used to extract the contents of
249 the Length field.
250
251 If Node is NULL, then ASSERT().
252
253 @param Node A pointer to a device path node data structure.
254
255 @return The 16-bit Length field of the device path node specified by Node.
256
257 **/
258 UINTN
259 EFIAPI
DevicePathNodeLength(IN CONST VOID * Node)260 DevicePathNodeLength (
261 IN CONST VOID *Node
262 )
263 {
264 ASSERT (Node != NULL);
265 return ((const EFI_DEVICE_PATH_PROTOCOL *)Node)->Length[0] |
266 (((const EFI_DEVICE_PATH_PROTOCOL *)Node)->Length[1] << 8);
267 }
268
269 /**
270 Returns a pointer to the next node in a device path.
271
272 Returns a pointer to the device path node that follows the device path node
273 specified by Node.
274
275 If Node is NULL, then ASSERT().
276
277 @param Node A pointer to a device path node data structure.
278
279 @return a pointer to the device path node that follows the device path node
280 specified by Node.
281
282 **/
283 EFI_DEVICE_PATH_PROTOCOL *
284 EFIAPI
NextDevicePathNode(IN CONST VOID * Node)285 NextDevicePathNode (
286 IN CONST VOID *Node
287 )
288 {
289 ASSERT (Node != NULL);
290 return ((EFI_DEVICE_PATH_PROTOCOL *)(__DECONST(UINT8 *, Node) + DevicePathNodeLength(Node)));
291 }
292
293 /**
294 Determines if a device path node is an end node of a device path.
295 This includes nodes that are the end of a device path instance and nodes that
296 are the end of an entire device path.
297
298 Determines if the device path node specified by Node is an end node of a device path.
299 This includes nodes that are the end of a device path instance and nodes that are the
300 end of an entire device path. If Node represents an end node of a device path,
301 then TRUE is returned. Otherwise, FALSE is returned.
302
303 If Node is NULL, then ASSERT().
304
305 @param Node A pointer to a device path node data structure.
306
307 @retval TRUE The device path node specified by Node is an end node of a
308 device path.
309 @retval FALSE The device path node specified by Node is not an end node of
310 a device path.
311
312 **/
313 BOOLEAN
314 EFIAPI
IsDevicePathEndType(IN CONST VOID * Node)315 IsDevicePathEndType (
316 IN CONST VOID *Node
317 )
318 {
319 ASSERT (Node != NULL);
320 return (BOOLEAN) (DevicePathType (Node) == END_DEVICE_PATH_TYPE);
321 }
322
323 /**
324 Determines if a device path node is an end node of an entire device path.
325
326 Determines if a device path node specified by Node is an end node of an entire
327 device path. If Node represents the end of an entire device path, then TRUE is
328 returned. Otherwise, FALSE is returned.
329
330 If Node is NULL, then ASSERT().
331
332 @param Node A pointer to a device path node data structure.
333
334 @retval TRUE The device path node specified by Node is the end of an entire
335 device path.
336 @retval FALSE The device path node specified by Node is not the end of an
337 entire device path.
338
339 **/
340 BOOLEAN
341 EFIAPI
IsDevicePathEnd(IN CONST VOID * Node)342 IsDevicePathEnd (
343 IN CONST VOID *Node
344 )
345 {
346 ASSERT (Node != NULL);
347 return (BOOLEAN) (IsDevicePathEndType (Node) && DevicePathSubType(Node) == END_ENTIRE_DEVICE_PATH_SUBTYPE);
348 }
349
350 /**
351 Fills in all the fields of a device path node that is the end of an entire device path.
352
353 Fills in all the fields of a device path node specified by Node so Node represents
354 the end of an entire device path. The Type field of Node is set to
355 END_DEVICE_PATH_TYPE, the SubType field of Node is set to
356 END_ENTIRE_DEVICE_PATH_SUBTYPE, and the Length field of Node is set to
357 END_DEVICE_PATH_LENGTH. Node is not required to be aligned on a 16-bit boundary,
358 so it is recommended that a function such as WriteUnaligned16() be used to set
359 the contents of the Length field.
360
361 If Node is NULL, then ASSERT().
362
363 @param Node A pointer to a device path node data structure.
364
365 **/
366 VOID
367 EFIAPI
SetDevicePathEndNode(OUT VOID * Node)368 SetDevicePathEndNode (
369 OUT VOID *Node
370 )
371 {
372 ASSERT (Node != NULL);
373 memcpy (Node, &mUefiDevicePathLibEndDevicePath, sizeof (mUefiDevicePathLibEndDevicePath));
374 }
375
376 /**
377 Sets the length, in bytes, of a device path node.
378
379 Sets the length of the device path node specified by Node to the value specified
380 by NodeLength. NodeLength is returned. Node is not required to be aligned on
381 a 16-bit boundary, so it is recommended that a function such as WriteUnaligned16()
382 be used to set the contents of the Length field.
383
384 If Node is NULL, then ASSERT().
385 If NodeLength >= SIZE_64KB, then ASSERT().
386 If NodeLength < sizeof (EFI_DEVICE_PATH_PROTOCOL), then ASSERT().
387
388 @param Node A pointer to a device path node data structure.
389 @param Length The length, in bytes, of the device path node.
390
391 @return Length
392
393 **/
394 UINT16
395 EFIAPI
SetDevicePathNodeLength(IN OUT VOID * Node,IN UINTN Length)396 SetDevicePathNodeLength (
397 IN OUT VOID *Node,
398 IN UINTN Length
399 )
400 {
401 ASSERT (Node != NULL);
402 ASSERT ((Length >= sizeof (EFI_DEVICE_PATH_PROTOCOL)) && (Length < SIZE_64KB));
403 // return WriteUnaligned16 ((UINT16 *)&((EFI_DEVICE_PATH_PROTOCOL *)(Node))->Length[0], (UINT16)(Length));
404 le16enc(&((EFI_DEVICE_PATH_PROTOCOL *)(Node))->Length[0], (UINT16)(Length));
405 return Length;
406 }
407
408 /**
409 Creates a device node.
410
411 This function creates a new device node in a newly allocated buffer of size
412 NodeLength and initializes the device path node header with NodeType and NodeSubType.
413 The new device path node is returned.
414 If NodeLength is smaller than a device path header, then NULL is returned.
415 If there is not enough memory to allocate space for the new device path, then
416 NULL is returned.
417 The memory is allocated from EFI boot services memory. It is the responsibility
418 of the caller to free the memory allocated.
419
420 @param NodeType The device node type for the new device node.
421 @param NodeSubType The device node sub-type for the new device node.
422 @param NodeLength The length of the new device node.
423
424 @return The new device path.
425
426 **/
427 EFI_DEVICE_PATH_PROTOCOL *
428 EFIAPI
CreateDeviceNode(IN UINT8 NodeType,IN UINT8 NodeSubType,IN UINT16 NodeLength)429 CreateDeviceNode (
430 IN UINT8 NodeType,
431 IN UINT8 NodeSubType,
432 IN UINT16 NodeLength
433 )
434 {
435 EFI_DEVICE_PATH_PROTOCOL *DevicePath;
436
437 if (NodeLength < sizeof (EFI_DEVICE_PATH_PROTOCOL)) {
438 //
439 // NodeLength is less than the size of the header.
440 //
441 return NULL;
442 }
443
444 DevicePath = AllocateZeroPool (NodeLength);
445 if (DevicePath != NULL) {
446 DevicePath->Type = NodeType;
447 DevicePath->SubType = NodeSubType;
448 SetDevicePathNodeLength (DevicePath, NodeLength);
449 }
450
451 return DevicePath;
452 }
453
454 /**
455 Creates a new copy of an existing device path.
456
457 This function allocates space for a new copy of the device path specified by DevicePath.
458 If DevicePath is NULL, then NULL is returned. If the memory is successfully
459 allocated, then the contents of DevicePath are copied to the newly allocated
460 buffer, and a pointer to that buffer is returned. Otherwise, NULL is returned.
461 The memory for the new device path is allocated from EFI boot services memory.
462 It is the responsibility of the caller to free the memory allocated.
463
464 @param DevicePath A pointer to a device path data structure.
465
466 @retval NULL DevicePath is NULL or invalid.
467 @retval Others A pointer to the duplicated device path.
468
469 **/
470 EFI_DEVICE_PATH_PROTOCOL *
471 EFIAPI
DuplicateDevicePath(IN CONST EFI_DEVICE_PATH_PROTOCOL * DevicePath)472 DuplicateDevicePath (
473 IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath
474 )
475 {
476 UINTN Size;
477
478 //
479 // Compute the size
480 //
481 Size = GetDevicePathSize (DevicePath);
482 if (Size == 0) {
483 return NULL;
484 }
485
486 //
487 // Allocate space for duplicate device path
488 //
489
490 return AllocateCopyPool (Size, DevicePath);
491 }
492
493 /**
494 Creates a new device path by appending a second device path to a first device path.
495
496 This function creates a new device path by appending a copy of SecondDevicePath
497 to a copy of FirstDevicePath in a newly allocated buffer. Only the end-of-device-path
498 device node from SecondDevicePath is retained. The newly created device path is
499 returned. If FirstDevicePath is NULL, then it is ignored, and a duplicate of
500 SecondDevicePath is returned. If SecondDevicePath is NULL, then it is ignored,
501 and a duplicate of FirstDevicePath is returned. If both FirstDevicePath and
502 SecondDevicePath are NULL, then a copy of an end-of-device-path is returned.
503
504 If there is not enough memory for the newly allocated buffer, then NULL is returned.
505 The memory for the new device path is allocated from EFI boot services memory.
506 It is the responsibility of the caller to free the memory allocated.
507
508 @param FirstDevicePath A pointer to a device path data structure.
509 @param SecondDevicePath A pointer to a device path data structure.
510
511 @retval NULL If there is not enough memory for the newly allocated buffer.
512 @retval NULL If FirstDevicePath or SecondDevicePath is invalid.
513 @retval Others A pointer to the new device path if success.
514 Or a copy an end-of-device-path if both FirstDevicePath and SecondDevicePath are NULL.
515
516 **/
517 EFI_DEVICE_PATH_PROTOCOL *
518 EFIAPI
AppendDevicePath(IN CONST EFI_DEVICE_PATH_PROTOCOL * FirstDevicePath,OPTIONAL IN CONST EFI_DEVICE_PATH_PROTOCOL * SecondDevicePath OPTIONAL)519 AppendDevicePath (
520 IN CONST EFI_DEVICE_PATH_PROTOCOL *FirstDevicePath, OPTIONAL
521 IN CONST EFI_DEVICE_PATH_PROTOCOL *SecondDevicePath OPTIONAL
522 )
523 {
524 UINTN Size;
525 UINTN Size1;
526 UINTN Size2;
527 EFI_DEVICE_PATH_PROTOCOL *NewDevicePath;
528 EFI_DEVICE_PATH_PROTOCOL *DevicePath2;
529
530 //
531 // If there's only 1 path, just duplicate it.
532 //
533 if (FirstDevicePath == NULL) {
534 return DuplicateDevicePath ((SecondDevicePath != NULL) ? SecondDevicePath : &mUefiDevicePathLibEndDevicePath);
535 }
536
537 if (SecondDevicePath == NULL) {
538 return DuplicateDevicePath (FirstDevicePath);
539 }
540
541 if (!IsDevicePathValid (FirstDevicePath, 0) || !IsDevicePathValid (SecondDevicePath, 0)) {
542 return NULL;
543 }
544
545 //
546 // Allocate space for the combined device path. It only has one end node of
547 // length EFI_DEVICE_PATH_PROTOCOL.
548 //
549 Size1 = GetDevicePathSize (FirstDevicePath);
550 Size2 = GetDevicePathSize (SecondDevicePath);
551 Size = Size1 + Size2 - END_DEVICE_PATH_LENGTH;
552
553 NewDevicePath = AllocatePool (Size);
554
555 if (NewDevicePath != NULL) {
556 NewDevicePath = CopyMem (NewDevicePath, FirstDevicePath, Size1);
557 //
558 // Over write FirstDevicePath EndNode and do the copy
559 //
560 DevicePath2 = (EFI_DEVICE_PATH_PROTOCOL *) ((CHAR8 *) NewDevicePath +
561 (Size1 - END_DEVICE_PATH_LENGTH));
562 CopyMem (DevicePath2, SecondDevicePath, Size2);
563 }
564
565 return NewDevicePath;
566 }
567
568 /**
569 Creates a new path by appending the device node to the device path.
570
571 This function creates a new device path by appending a copy of the device node
572 specified by DevicePathNode to a copy of the device path specified by DevicePath
573 in an allocated buffer. The end-of-device-path device node is moved after the
574 end of the appended device node.
575 If DevicePathNode is NULL then a copy of DevicePath is returned.
576 If DevicePath is NULL then a copy of DevicePathNode, followed by an end-of-device
577 path device node is returned.
578 If both DevicePathNode and DevicePath are NULL then a copy of an end-of-device-path
579 device node is returned.
580 If there is not enough memory to allocate space for the new device path, then
581 NULL is returned.
582 The memory is allocated from EFI boot services memory. It is the responsibility
583 of the caller to free the memory allocated.
584
585 @param DevicePath A pointer to a device path data structure.
586 @param DevicePathNode A pointer to a single device path node.
587
588 @retval NULL If there is not enough memory for the new device path.
589 @retval Others A pointer to the new device path if success.
590 A copy of DevicePathNode followed by an end-of-device-path node
591 if both FirstDevicePath and SecondDevicePath are NULL.
592 A copy of an end-of-device-path node if both FirstDevicePath
593 and SecondDevicePath are NULL.
594
595 **/
596 EFI_DEVICE_PATH_PROTOCOL *
597 EFIAPI
AppendDevicePathNode(IN CONST EFI_DEVICE_PATH_PROTOCOL * DevicePath,OPTIONAL IN CONST EFI_DEVICE_PATH_PROTOCOL * DevicePathNode OPTIONAL)598 AppendDevicePathNode (
599 IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePath, OPTIONAL
600 IN CONST EFI_DEVICE_PATH_PROTOCOL *DevicePathNode OPTIONAL
601 )
602 {
603 EFI_DEVICE_PATH_PROTOCOL *TempDevicePath;
604 EFI_DEVICE_PATH_PROTOCOL *NextNode;
605 EFI_DEVICE_PATH_PROTOCOL *NewDevicePath;
606 UINTN NodeLength;
607
608 if (DevicePathNode == NULL) {
609 return DuplicateDevicePath ((DevicePath != NULL) ? DevicePath : &mUefiDevicePathLibEndDevicePath);
610 }
611 //
612 // Build a Node that has a terminator on it
613 //
614 NodeLength = DevicePathNodeLength (DevicePathNode);
615
616 TempDevicePath = AllocatePool (NodeLength + END_DEVICE_PATH_LENGTH);
617 if (TempDevicePath == NULL) {
618 return NULL;
619 }
620 TempDevicePath = CopyMem (TempDevicePath, DevicePathNode, NodeLength);
621 //
622 // Add and end device path node to convert Node to device path
623 //
624 NextNode = NextDevicePathNode (TempDevicePath);
625 SetDevicePathEndNode (NextNode);
626 //
627 // Append device paths
628 //
629 NewDevicePath = AppendDevicePath (DevicePath, TempDevicePath);
630
631 FreePool (TempDevicePath);
632
633 return NewDevicePath;
634 }
635