1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
|
/** @file
ELF library
Copyright (c) 2019 - 2021, Intel Corporation. All rights reserved.<BR>
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
#include "ElfLibInternal.h"
/**
Check if the ELF image is valid.
@param[in] ImageBase Memory address of an image.
@retval TRUE if valid.
**/
BOOLEAN
IsElfFormat (
IN CONST UINT8 *ImageBase
)
{
Elf32_Ehdr *Elf32Hdr;
Elf64_Ehdr *Elf64Hdr;
ASSERT (ImageBase != NULL);
Elf32Hdr = (Elf32_Ehdr *)ImageBase;
//
// Start with correct signature "\7fELF"
//
if ((Elf32Hdr->e_ident[EI_MAG0] != ELFMAG0) ||
(Elf32Hdr->e_ident[EI_MAG1] != ELFMAG1) ||
(Elf32Hdr->e_ident[EI_MAG1] != ELFMAG1) ||
(Elf32Hdr->e_ident[EI_MAG2] != ELFMAG2)
) {
return FALSE;
}
//
// Support little-endian only
//
if (Elf32Hdr->e_ident[EI_DATA] != ELFDATA2LSB) {
return FALSE;
}
//
// Check 32/64-bit architecture
//
if (Elf32Hdr->e_ident[EI_CLASS] == ELFCLASS64) {
Elf64Hdr = (Elf64_Ehdr *)Elf32Hdr;
Elf32Hdr = NULL;
} else if (Elf32Hdr->e_ident[EI_CLASS] == ELFCLASS32) {
Elf64Hdr = NULL;
} else {
return FALSE;
}
if (Elf64Hdr != NULL) {
//
// Support intel architecture only for now
//
if (Elf64Hdr->e_machine != EM_X86_64) {
return FALSE;
}
//
// Support ELF types: EXEC (Executable file), DYN (Shared object file)
//
if ((Elf64Hdr->e_type != ET_EXEC) && (Elf64Hdr->e_type != ET_DYN)) {
return FALSE;
}
//
// Support current ELF version only
//
if (Elf64Hdr->e_version != EV_CURRENT) {
return FALSE;
}
} else {
//
// Support intel architecture only for now
//
if (Elf32Hdr->e_machine != EM_386) {
return FALSE;
}
//
// Support ELF types: EXEC (Executable file), DYN (Shared object file)
//
if ((Elf32Hdr->e_type != ET_EXEC) && (Elf32Hdr->e_type != ET_DYN)) {
return FALSE;
}
//
// Support current ELF version only
//
if (Elf32Hdr->e_version != EV_CURRENT) {
return FALSE;
}
}
return TRUE;
}
/**
Calculate a ELF file size.
@param[in] ElfCt ELF image context pointer.
@param[out] FileSize Return the file size.
@retval EFI_INVALID_PARAMETER ElfCt or SecPos is NULL.
@retval EFI_NOT_FOUND Could not find the section.
@retval EFI_SUCCESS Section posistion was filled successfully.
**/
EFI_STATUS
CalculateElfFileSize (
IN ELF_IMAGE_CONTEXT *ElfCt,
OUT UINTN *FileSize
)
{
EFI_STATUS Status;
UINTN FileSize1;
UINTN FileSize2;
Elf32_Ehdr *Elf32Hdr;
Elf64_Ehdr *Elf64Hdr;
UINTN Offset;
UINTN Size;
if ((ElfCt == NULL) || (FileSize == NULL)) {
return EFI_INVALID_PARAMETER;
}
// Use last section as end of file
Status = GetElfSectionPos (ElfCt, ElfCt->ShNum - 1, &Offset, &Size);
if (EFI_ERROR(Status)) {
return EFI_UNSUPPORTED;
}
FileSize1 = Offset + Size;
// Use end of section header as end of file
FileSize2 = 0;
if (ElfCt->EiClass == ELFCLASS32) {
Elf32Hdr = (Elf32_Ehdr *)ElfCt->FileBase;
FileSize2 = Elf32Hdr->e_shoff + Elf32Hdr->e_shentsize * Elf32Hdr->e_shnum;
} else if (ElfCt->EiClass == ELFCLASS64) {
Elf64Hdr = (Elf64_Ehdr *)ElfCt->FileBase;
FileSize2 = (UINTN)(Elf64Hdr->e_shoff + Elf64Hdr->e_shentsize * Elf64Hdr->e_shnum);
}
*FileSize = MAX(FileSize1, FileSize2);
return EFI_SUCCESS;
}
/**
Get a ELF program segment loading info.
@param[in] ImageBase Image base.
@param[in] EiClass ELF class.
@param[in] Index ELF segment index.
@param[out] SegInfo The pointer to the segment info.
@retval EFI_INVALID_PARAMETER ElfCt or SecPos is NULL.
@retval EFI_NOT_FOUND Could not find the section.
@retval EFI_SUCCESS Section posistion was filled successfully.
**/
EFI_STATUS
GetElfSegmentInfo (
IN UINT8 *ImageBase,
IN UINT32 EiClass,
IN UINT32 Index,
OUT SEGMENT_INFO *SegInfo
)
{
Elf32_Phdr *Elf32Phdr;
Elf64_Phdr *Elf64Phdr;
if ((ImageBase == NULL) || (SegInfo == NULL)) {
return EFI_INVALID_PARAMETER;
}
if (EiClass == ELFCLASS32) {
Elf32Phdr = GetElf32SegmentByIndex (ImageBase, Index);
if (Elf32Phdr != NULL) {
SegInfo->PtType = Elf32Phdr->p_type;
SegInfo->Offset = Elf32Phdr->p_offset;
SegInfo->Length = Elf32Phdr->p_filesz;
SegInfo->MemLen = Elf32Phdr->p_memsz;
SegInfo->MemAddr = Elf32Phdr->p_paddr;
SegInfo->Alignment = Elf32Phdr->p_align;
return EFI_SUCCESS;
}
} else if (EiClass == ELFCLASS64) {
Elf64Phdr = GetElf64SegmentByIndex (ImageBase, Index);
if (Elf64Phdr != NULL) {
SegInfo->PtType = Elf64Phdr->p_type;
SegInfo->Offset = (UINTN)Elf64Phdr->p_offset;
SegInfo->Length = (UINTN)Elf64Phdr->p_filesz;
SegInfo->MemLen = (UINTN)Elf64Phdr->p_memsz;
SegInfo->MemAddr = (UINTN)Elf64Phdr->p_paddr;
SegInfo->Alignment = (UINTN)Elf64Phdr->p_align;
return EFI_SUCCESS;
}
}
return EFI_NOT_FOUND;
}
/**
Parse the ELF image info.
On return, all fields in ElfCt are updated except ImageAddress.
@param[in] ImageBase Memory address of an image.
@param[out] ElfCt The EFL image context pointer.
@retval EFI_INVALID_PARAMETER Input parameters are not valid.
@retval EFI_UNSUPPORTED Unsupported binary type.
@retval EFI_LOAD_ERROR ELF binary loading error.
@retval EFI_SUCCESS ELF binary is loaded successfully.
**/
EFI_STATUS
EFIAPI
ParseElfImage (
IN VOID *ImageBase,
OUT ELF_IMAGE_CONTEXT *ElfCt
)
{
Elf32_Ehdr *Elf32Hdr;
Elf64_Ehdr *Elf64Hdr;
Elf32_Shdr *Elf32Shdr;
Elf64_Shdr *Elf64Shdr;
EFI_STATUS Status;
UINT32 Index;
SEGMENT_INFO SegInfo;
UINTN End;
UINTN Base;
if (ElfCt == NULL) {
return EFI_INVALID_PARAMETER;
}
ZeroMem (ElfCt, sizeof(ELF_IMAGE_CONTEXT));
if (ImageBase == NULL) {
return (ElfCt->ParseStatus = EFI_INVALID_PARAMETER);
}
ElfCt->FileBase = (UINT8 *)ImageBase;
if (!IsElfFormat (ElfCt->FileBase)) {
return (ElfCt->ParseStatus = EFI_UNSUPPORTED);
}
Elf32Hdr = (Elf32_Ehdr *)ElfCt->FileBase;
ElfCt->EiClass = Elf32Hdr->e_ident[EI_CLASS];
if (ElfCt->EiClass == ELFCLASS32) {
if ((Elf32Hdr->e_type != ET_EXEC) && (Elf32Hdr->e_type != ET_DYN)) {
return (ElfCt->ParseStatus = EFI_UNSUPPORTED);
}
Elf32Shdr = (Elf32_Shdr *)GetElf32SectionByIndex (ElfCt->FileBase, Elf32Hdr->e_shstrndx);
if (Elf32Shdr == NULL) {
return (ElfCt->ParseStatus = EFI_UNSUPPORTED);
}
ElfCt->EntryPoint = (UINTN)Elf32Hdr->e_entry;
ElfCt->ShNum = Elf32Hdr->e_shnum;
ElfCt->PhNum = Elf32Hdr->e_phnum;
ElfCt->ShStrLen = Elf32Shdr->sh_size;
ElfCt->ShStrOff = Elf32Shdr->sh_offset;
} else {
Elf64Hdr = (Elf64_Ehdr *)Elf32Hdr;
if ((Elf64Hdr->e_type != ET_EXEC) && (Elf64Hdr->e_type != ET_DYN)) {
return (ElfCt->ParseStatus = EFI_UNSUPPORTED);
}
Elf64Shdr = (Elf64_Shdr *)GetElf64SectionByIndex (ElfCt->FileBase, Elf64Hdr->e_shstrndx);
if (Elf64Shdr == NULL) {
return (ElfCt->ParseStatus = EFI_UNSUPPORTED);
}
ElfCt->EntryPoint = (UINTN)Elf64Hdr->e_entry;
ElfCt->ShNum = Elf64Hdr->e_shnum;
ElfCt->PhNum = Elf64Hdr->e_phnum;
ElfCt->ShStrLen = (UINT32)Elf64Shdr->sh_size;
ElfCt->ShStrOff = (UINT32)Elf64Shdr->sh_offset;
}
//
// Get the preferred image base and required memory size when loaded to new location.
//
End = 0;
Base = MAX_UINT32;
ElfCt->ReloadRequired = FALSE;
for (Index = 0; Index < ElfCt->PhNum; Index++) {
Status = GetElfSegmentInfo (ElfCt->FileBase, ElfCt->EiClass, Index, &SegInfo);
ASSERT_EFI_ERROR (Status);
if (SegInfo.PtType != PT_LOAD) {
continue;
}
if (SegInfo.MemLen != SegInfo.Length) {
//
// Not enough space to execute at current location.
//
ElfCt->ReloadRequired = TRUE;
}
if (Base > (SegInfo.MemAddr & ~(EFI_PAGE_SIZE - 1))) {
Base = SegInfo.MemAddr & ~(EFI_PAGE_SIZE - 1);
}
if (End < ALIGN_VALUE (SegInfo.MemAddr + SegInfo.MemLen, EFI_PAGE_SIZE) - 1) {
End = ALIGN_VALUE (SegInfo.MemAddr + SegInfo.MemLen, EFI_PAGE_SIZE) - 1;
}
}
//
// 0 - MAX_UINT32 + 1 equals to 0.
//
ElfCt->ImageSize = End - Base + 1;
ElfCt->PreferredImageAddress = (VOID *) Base;
CalculateElfFileSize (ElfCt, &ElfCt->FileSize);
return (ElfCt->ParseStatus = EFI_SUCCESS);;
}
/**
Load the ELF image to Context.ImageAddress.
Context should be initialized by ParseElfImage().
Caller should set Context.ImageAddress to a proper value, either pointing to
a new allocated memory whose size equal to Context.ImageSize, or pointing
to Context.PreferredImageAddress.
@param[in] ElfCt ELF image context pointer.
@retval EFI_INVALID_PARAMETER Input parameters are not valid.
@retval EFI_UNSUPPORTED Unsupported binary type.
@retval EFI_LOAD_ERROR ELF binary loading error.
@retval EFI_SUCCESS ELF binary is loaded successfully.
**/
EFI_STATUS
EFIAPI
LoadElfImage (
IN ELF_IMAGE_CONTEXT *ElfCt
)
{
EFI_STATUS Status;
if (ElfCt == NULL) {
return EFI_INVALID_PARAMETER;
}
if (EFI_ERROR (ElfCt->ParseStatus)) {
return ElfCt->ParseStatus;
}
if (ElfCt->ImageAddress == NULL) {
return EFI_INVALID_PARAMETER;
}
Status = EFI_UNSUPPORTED;
if (ElfCt->EiClass == ELFCLASS32) {
Status = LoadElf32Image (ElfCt);
} else if (ElfCt->EiClass == ELFCLASS64) {
Status = LoadElf64Image (ElfCt);
}
return Status;
}
/**
Get a ELF section name from its index.
@param[in] ElfCt ELF image context pointer.
@param[in] SectionIndex ELF section index.
@param[out] SectionName The pointer to the section name.
@retval EFI_INVALID_PARAMETER ElfCt or SecName is NULL.
@retval EFI_NOT_FOUND Could not find the section.
@retval EFI_SUCCESS Section name was filled successfully.
**/
EFI_STATUS
EFIAPI
GetElfSectionName (
IN ELF_IMAGE_CONTEXT *ElfCt,
IN UINT32 SectionIndex,
OUT CHAR8 **SectionName
)
{
Elf32_Shdr *Elf32Shdr;
Elf64_Shdr *Elf64Shdr;
CHAR8 *Name;
if ((ElfCt == NULL) || (SectionName == NULL)) {
return EFI_INVALID_PARAMETER;
}
if (EFI_ERROR (ElfCt->ParseStatus)) {
return ElfCt->ParseStatus;
}
Name = NULL;
if (ElfCt->EiClass == ELFCLASS32) {
Elf32Shdr = GetElf32SectionByIndex (ElfCt->FileBase, SectionIndex);
if ((Elf32Shdr != NULL) && (Elf32Shdr->sh_name < ElfCt->ShStrLen)) {
Name = (CHAR8 *)(ElfCt->FileBase + ElfCt->ShStrOff + Elf32Shdr->sh_name);
}
} else if (ElfCt->EiClass == ELFCLASS64) {
Elf64Shdr = GetElf64SectionByIndex (ElfCt->FileBase, SectionIndex);
if ((Elf64Shdr != NULL) && (Elf64Shdr->sh_name < ElfCt->ShStrLen)) {
Name = (CHAR8 *)(ElfCt->FileBase + ElfCt->ShStrOff + Elf64Shdr->sh_name);
}
}
if (Name == NULL) {
return EFI_NOT_FOUND;
}
*SectionName = Name;
return EFI_SUCCESS;
}
/**
Get the offset and size of x-th ELF section.
@param[in] ElfCt ELF image context pointer.
@param[in] Index ELF section index.
@param[out] Offset Return the offset of the specific section.
@param[out] Size Return the size of the specific section.
@retval EFI_INVALID_PARAMETER ImageBase, Offset or Size is NULL.
@retval EFI_INVALID_PARAMETER EiClass doesn't equal to ELFCLASS32 or ELFCLASS64.
@retval EFI_NOT_FOUND Could not find the section.
@retval EFI_SUCCESS Offset and Size are returned.
**/
EFI_STATUS
EFIAPI
GetElfSectionPos (
IN ELF_IMAGE_CONTEXT *ElfCt,
IN UINT32 Index,
OUT UINTN *Offset,
OUT UINTN *Size
)
{
Elf32_Shdr *Elf32Shdr;
Elf64_Shdr *Elf64Shdr;
if ((ElfCt == NULL) || (Offset == NULL) || (Size == NULL)) {
return EFI_INVALID_PARAMETER;
}
if (EFI_ERROR (ElfCt->ParseStatus)) {
return ElfCt->ParseStatus;
}
if (ElfCt->EiClass == ELFCLASS32) {
Elf32Shdr = GetElf32SectionByIndex (ElfCt->FileBase, Index);
if (Elf32Shdr != NULL) {
*Offset = (UINTN)Elf32Shdr->sh_offset;
*Size = (UINTN)Elf32Shdr->sh_size;
return EFI_SUCCESS;
}
} else if (ElfCt->EiClass == ELFCLASS64) {
Elf64Shdr = GetElf64SectionByIndex (ElfCt->FileBase, Index);
if (Elf64Shdr != NULL) {
*Offset = (UINTN)Elf64Shdr->sh_offset;
*Size = (UINTN)Elf64Shdr->sh_size;
return EFI_SUCCESS;
}
}
return EFI_NOT_FOUND;
}
|