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Root/branches/meklort/i386/boot2/kernel_patcher.c

Source at commit 148 created 13 years 11 months ago.
By meklort, 915resolution code
1/*␊
2 * Copyright (c) 2009 Evan Lojewski. All rights reserved.␊
3 *␊
4 */␊
5␊
6#include "libsaio.h"␊
7#include "kernel_patcher.h"␊
8␊
9#define NUM_SYMBOLS␉␉3␊
10␊
11#define SYMBOL_CPUID_SET_INFO␉␉␉␉0␊
12#define SYMBOL_PANIC␉␉␉␉␉␉1␊
13#define SYMBOL_PMCPUEXITHALTTOOFF␉␉␉2␊
14␊
15#define SYMBOL_CPUID_SET_INFO_STRING␉␉"_cpuid_set_info"␊
16#define SYMBOL_PANIC_STRING␉␉␉␉␉"_panic"␊
17#define SYMBOL_PMCPUEXITHALTTOOFF_STRING␉"_pmCPUExitHaltToOff"␊
18␊
19char* kernelSymbols[NUM_SYMBOLS] = {␊
20␉SYMBOL_CPUID_SET_INFO_STRING,␊
21␉SYMBOL_PANIC_STRING,␊
22␉SYMBOL_PMCPUEXITHALTTOOFF_STRING␊
23};␊
24␊
25UInt32 kernelSymbolAddresses[NUM_SYMBOLS] = {␊
26␉0,␊
27␉0,␊
28␉0␊
29};␊
30␊
31␊
32UInt32 textSection = 0;␊
33UInt32 textAddress = 0;␊
34␊
35␊
36extern unsigned long gBinaryAddress;␊
37␊
38␊
39void patch_kernel(void* kernelData)␊
40{␊
41␉switch (locate_symbols((void*)kernelData)) {␊
42␉␉case KERNEL_32:␊
43␉␉␉patch_kernel_32((void*)kernelData);␊
44␉␉␉break;␊
45␉␉␉␊
46␉␉case KERNEL_64:␊
47␉␉default:␊
48␉␉␉patch_kernel_64((void*)kernelData);␊
49␉␉␉break;␊
50␉}␊
51}␊
52␊
53// patches a 64bit kernel.␊
54void patch_kernel_64(void* kernelData)␊
55{␊
56␉// At the moment, the kernel patching code fails when used␊
57␉// in 64bit mode, so we don't patch it. This is due to 32bit vs 64bit␊
58␉// pointers as well as changes in structure sizes␊
59␉printf("Unable to patch 64bit kernel. Please use arch=i386.\n");␊
60}␊
61␊
62␊
63/**␊
64 ** patch_kernel_32␊
65 **␉␉Due to the way the _cpuid_set_info function is writtin, the first instance of _panic is called␊
66 **␉␉␉when an unsupported (read: non apple used cpu) is found. This routine locates that first _panic call␊
67 **␉␉␉and replaces the jump call (0xe8) with no ops (0x90).␊
68 **/␊
69void patch_kernel_32(void* kernelData)␊
70{␊
71␉//patch_pmCPUExitHaltToOff(kernelData);␉// Not working as intended, disabled for now␊
72␉patch_cpuid_set_info(kernelData);␊
73␊
74}␊
75␊
76␊
77/**␊
78 **␉␉This functions located the following in the mach_kernel symbol table␊
79 **␉␉␉_panic␊
80 **␉␉␉_cpuid_set_info␊
81 **/␊
82int locate_symbols(void* kernelData)␊
83{␊
84␉UInt16 symbolIndexes[NUM_SYMBOLS];␊
85␊
86␉struct load_command *loadCommand;␊
87␉struct symtab_command *symtableData;␊
88␉struct nlist *symbolEntry;␊
89␉␊
90␉char* symbolString;␊
91␊
92␉UInt32 kernelIndex = 0;␊
93␉kernelIndex += sizeof(struct mach_header);␊
94␉␊
95␉if(((struct mach_header*)kernelData)->magic != MH_MAGIC) return KERNEL_64;␊
96␉␊
97␉␊
98␉//printf("%d load commands beginning at 0x%X\n", (unsigned int)header->ncmds, (unsigned int)kernelIndex);␊
99␉//printf("Commands take up %d bytes\n", header->sizeofcmds);␊
100␉␊
101␉␊
102␉int cmd = 0;␊
103␉while(cmd < ((struct mach_header*)kernelData)->ncmds)␉// TODO: for loop instead␊
104␉{␊
105␉␉cmd++;␊
106␉␉␊
107␉␉loadCommand = kernelData + kernelIndex;␊
108␉␉␊
109␉␉UInt cmdSize = loadCommand->cmdsize;␊
110␉␉␊
111␉␉␊
112␉␉// Locate start of _panic and _cpuid_set_info in the symbol tabe.␊
113␉␉// Load commands should be anded with 0x7FFFFFFF to ignore the␉LC_REQ_DYLD flag␊
114␉␉if((loadCommand->cmd & 0x7FFFFFFF) == LC_SYMTAB)␉␉// We only care about the symtab segment␊
115␉␉{␊
116␉␉␉//printf("Located symtable, length is 0x%X, 0x%X\n", (unsigned int)loadCommand->cmdsize, (unsigned int)sizeof(symtableData));␊
117␉␉␉␊
118␉␉␉symtableData = kernelData + kernelIndex;␊
119␉␉␉kernelIndex += sizeof(struct symtab_command);␊
120␉␉␉␊
121␉␉␉cmdSize -= sizeof(struct symtab_command);␊
122␊
123␉␉␉// Loop through symbol table untill all of the symbols have been found␊
124␉␉␉␊
125␉␉␉symbolString = kernelData + symtableData->stroff; ␊
126␉␉␉␊
127␉␉␉␊
128␉␉␉UInt16 symbolIndex = 0;␊
129␉␉␉UInt8 numSymbolsFound = 0;␊
130␊
131␉␉␉while(symbolIndex < symtableData->nsyms && numSymbolsFound < NUM_SYMBOLS)␉// TODO: for loop␊
132␉␉␉{␊
133␉␉␉␉int i = 0;␊
134␉␉␉␉while(i < NUM_SYMBOLS)␊
135␉␉␉␉{␊
136␉␉␉␉␉if(strcmp(symbolString, kernelSymbols[i]) == 0)␊
137␉␉␉␉␉{␊
138␉␉␉␉␉␉symbolIndexes[i] = symbolIndex;␊
139␉␉␉␉␉␉numSymbolsFound++;␉␉␉␉␊
140␉␉␉␉␉} ␊
141␉␉␉␉␉i++;␊
142␉␉␉␉␉␊
143␉␉␉␉}␊
144␉␉␉␉symbolString += strlen(symbolString) + 1;␊
145␉␉␉␉symbolIndex++;␊
146␉␉␉}␊
147␉␉␉␊
148␉␉␉// loop again␊
149␉␉␉symbolIndex = 0;␊
150␉␉␉numSymbolsFound = 0;␊
151␉␉␉while(symbolIndex < symtableData->nsyms && numSymbolsFound < NUM_SYMBOLS)␉// TODO: for loop␊
152␉␉␉{␊
153␉␉␉␉␊
154␉␉␉␉symbolEntry = kernelData + symtableData->symoff + (symbolIndex * sizeof(struct nlist));␊
155␉␉␉␉␊
156␉␉␉␉int i = 0;␊
157␉␉␉␉while(i < NUM_SYMBOLS)␊
158␉␉␉␉{␊
159␉␉␉␉␉if(symbolIndex == (symbolIndexes[i] - 4))␊
160␉␉␉␉␉{␊
161␉␉␉␉␉␉kernelSymbolAddresses[i] = (UInt32)symbolEntry->n_value;␊
162␉␉␉␉␉␉numSymbolsFound++;␉␉␉␉␊
163␉␉␉␉␉} ␊
164␉␉␉␉␉i++;␊
165␉␉␉␉␉␊
166␉␉␉␉}␊
167␉␉␉␉␊
168␉␉␉␉symbolIndex ++;␊
169␉␉␉}␉␉␉␊
170␉␉// Load commands should be anded with 0x7FFFFFFF to ignore the␉LC_REQ_DYLD flag␊
171␉␉} else if((loadCommand->cmd & 0x7FFFFFFF) == LC_SEGMENT)␉␉// We only care about the __TEXT segment, any other load command can be ignored␊
172␉␉{␊
173␉␉␉␊
174␉␉␉struct segment_command *segCommand;␊
175␉␉␉␊
176␉␉␉segCommand = kernelData + kernelIndex;␊
177␉␉␉␊
178␉␉␉//printf("Segment name is %s\n", segCommand->segname);␊
179␉␉␉␊
180␉␉␉if(strcmp("__TEXT", segCommand->segname) == 0)␊
181␉␉␉{␊
182␉␉␉␉UInt32 sectionIndex;␊
183␉␉␉␉␊
184␉␉␉␉sectionIndex = sizeof(struct segment_command);␊
185␉␉␉␉␊
186␉␉␉␉struct section *sect;␊
187␉␉␉␉␊
188␉␉␉␉while(sectionIndex < segCommand->cmdsize)␊
189␉␉␉␉{␊
190␉␉␉␉␉sect = kernelData + kernelIndex + sectionIndex;␊
191␉␉␉␉␉␊
192␉␉␉␉␉sectionIndex += sizeof(struct section);␊
193␉␉␉␉␉␊
194␉␉␉␉␉␊
195␉␉␉␉␉if(strcmp("__text", sect->sectname) == 0)␊
196␉␉␉␉␉{␊
197␉␉␉␉␉␉// __TEXT,__text found, save the offset and address for when looking for the calls.␊
198␉␉␉␉␉␉textSection = sect->offset;␊
199␉␉␉␉␉␉textAddress = sect->addr;␊
200␉␉␉␉␉␉break;␊
201␉␉␉␉␉}␉␉␉␉␉␊
202␉␉␉␉}␊
203␉␉␉}␊
204␉␉␉␊
205␉␉␉␊
206␉␉␉kernelIndex += cmdSize;␊
207␉␉} else {␊
208␉␉␉kernelIndex += cmdSize;␊
209␉␉}␊
210␉}␊
211␉␊
212␉return KERNEL_32;␊
213}␊
214␊
215␊
216/**␊
217 ** Locate the fisrt instance of _panic inside of _cpuid_set_info, and remove it␊
218 **/␊
219void patch_cpuid_set_info(void* kernelData)␊
220{␊
221␉UInt8* bytes = (UInt8*)kernelData;␊
222␉UInt32 patchLocation = (kernelSymbolAddresses[SYMBOL_CPUID_SET_INFO] - textAddress + textSection);␊
223␉UInt32 jumpLocation = 0;␊
224␉UInt32 panidAddr = kernelSymbolAddresses[SYMBOL_PANIC] - textAddress;␊
225␉if(kernelSymbolAddresses[SYMBOL_CPUID_SET_INFO] == 0)␊
226␉{␊
227␉␉printf("Unable to locate _cpuid_set_info\n");␊
228␉␉return;␊
229␉␉␊
230␉}␊
231␉if(kernelSymbolAddresses[SYMBOL_PANIC] == 0)␊
232␉{␊
233␉␉printf("Unable to locate _panic\n");␊
234␉␉return;␊
235␉}␊
236␉␊
237␉//TODO: don't assume it'll always work (Look for *next* function address in symtab and fail once it's been reached)␊
238␉while( ␊
239␉␉ (bytes[patchLocation -1] != 0xE8) ||␊
240␉␉ ( ( (UInt32)(panidAddr - patchLocation - 4) + textSection ) != (UInt32)((bytes[patchLocation + 0] << 0 | ␊
241␉␉␉␉␉␉␉␉␉␉␉␉␉␉␉␉␉␉␉␉␉bytes[patchLocation + 1] << 8 | ␊
242␉␉␉␉␉␉␉␉␉␉␉␉␉␉␉␉␉␉␉␉␉bytes[patchLocation + 2] << 16 |␊
243␉␉␉␉␉␉␉␉␉␉␉␉␉␉␉␉␉␉␉␉␉bytes[patchLocation + 3] << 24)))␊
244␉␉ )␊
245␉{␊
246␉␉patchLocation++;␊
247␉}␊
248␉patchLocation--;␊
249␉␊
250/*␊
251 // repace with nops to disable the panic call␊
252␉Old patch, nolonger used. This is a safer patch than before, however␊
253␉the new patch allows the native pm kext to load without any extra kexts␊
254␉bytes[patchLocation] = 0x90;␊
255␉bytes[patchLocation + 1] = 0x90;␊
256␉bytes[patchLocation + 2] = 0x90;␊
257␉bytes[patchLocation + 3] = 0x90;␊
258␉bytes[patchLocation + 4] = 0x90;␊
259*/␉␊
260␉␊
261␉// Locate a JMP to patchLocation - sizeof(mov) + 2 (aka 8)␊
262␉// ... NOTE: can *ONLY* be up to 0xFF - 8 bytes aways␊
263␉jumpLocation = patchLocation - 15;␊
264␉while((bytes[jumpLocation - 1] != 0x77 ||␊
265␉␉ bytes[jumpLocation] != (patchLocation - jumpLocation - -8)) &&␊
266␉␉ (patchLocation - jumpLocation) < 0xEF)␊
267␉{␊
268␉␉jumpLocation--;␊
269␉}␊
270␉␊
271␉// If found... (not the end of the world if it isn't found, the panic is removed either way.␊
272␉// But if it isn't found, then IntelCPUPM.kext might panic if an unknown cpu (atom)␊
273␉// Jump to patchLocation - 17␊
274␉if((patchLocation - jumpLocation) < 0xEF) bytes[jumpLocation] -= 10; // sizeof(movl␉$0x6b5a4cd2,0x00872eb4)␊
275␉␊
276␉␊
277␉// bytes[patchLocation - 17] = 0xC7;␉// already here... not needed to be done␊
278␉// bytes[patchLocation - 16] = 0x05;␉// see above␊
279␉UInt32 cpuid_cpufamily_addr =␉bytes[patchLocation - 15] << 0 |␊
280␉␉␉␉␉␉␉␉␉bytes[patchLocation - 14] << 8 |␊
281␉␉␉␉␉␉␉␉␉bytes[patchLocation - 13] << 16 |␊
282␉␉␉␉␉␉␉␉␉bytes[patchLocation - 12] << 24;␊
283␉␊
284␉// NOTE: may change, determined based on cpuid_info struct␊
285␉UInt32 cpuid_model_addr = cpuid_cpufamily_addr - 299; ␊
286␉␊
287␉␊
288␉// cpufamily = CPUFAMILY_INTEL_PENRYN␊
289␉bytes[patchLocation - 11] = (CPUFAMILY_INTEL_PENRYN & 0x000000FF) >> 0;␊
290␉bytes[patchLocation - 10] = (CPUFAMILY_INTEL_PENRYN & 0x0000FF00) >> 8;␊
291␉bytes[patchLocation - 9] = (CPUFAMILY_INTEL_PENRYN & 0x00FF0000) >> 16;␉␊
292␉bytes[patchLocation - 8] = (CPUFAMILY_INTEL_PENRYN & 0xFF000000) >> 24;␊
293␊
294␉// NOPS, just in case if the jmp call wasn't patched, we'll jump to a␊
295␉// nop and continue with the rest of the patch␊
296␉// Yay two free bytes :), 10 more can be reclamed if needed, as well as a few␊
297␉// from the above code (only cpuid_model needs to be set.␊
298␉bytes[patchLocation - 7] = 0x90;␊
299␉bytes[patchLocation - 6] = 0x90;␊
300␊
301␉bytes[patchLocation - 5] = 0xC7;␊
302␉bytes[patchLocation - 4] = 0x05;␊
303␉bytes[patchLocation - 3] = (cpuid_model_addr & 0x000000FF) >> 0;␊
304␉bytes[patchLocation - 2] = (cpuid_model_addr & 0x0000FF00) >> 8;␉␊
305␉bytes[patchLocation - 1] = (cpuid_model_addr & 0x00FF0000) >> 16;␊
306␉bytes[patchLocation - 0] = (cpuid_model_addr & 0xFF000000) >> 24;␊
307␉␊
308␉// Note: I could have just copied the 8bit cpuid_model in and saved about 4 bytes␊
309␉// so if this function need a different patch it's still possible. Also, about ten bytes previous can be freed.␊
310␉bytes[patchLocation + 1] = 0x17;␉// cpuid_model␊
311␉bytes[patchLocation + 2] = 0x01;␉// cpuid_extmodel␊
312␉bytes[patchLocation + 3] = 0x00;␉// cpuid_extfamily␊
313␉bytes[patchLocation + 4] = 0x02;␉// cpuid_stepping␊
314␉␊
315}␊
316␊
317␊
318/**␊
319 ** SleepEnabler.kext replacement (for those that need it)␊
320 ** Located the KERN_INVALID_ARGUMENT return and replace it with KERN_SUCCESS␊
321 **/␊
322void patch_pmCPUExitHaltToOff(void* kernelData)␊
323{␊
324␉UInt8* bytes = (UInt8*)kernelData;␊
325␉UInt32 patchLocation = (kernelSymbolAddresses[SYMBOL_PMCPUEXITHALTTOOFF] - textAddress + textSection);␊
326␊
327␉if(kernelSymbolAddresses[SYMBOL_PMCPUEXITHALTTOOFF] == 0)␊
328␉{␊
329␉␉printf("Unable to locate _pmCPUExitHaltToOff\n");␊
330␉␉return;␊
331␉}␊
332␉␊
333␉while(bytes[patchLocation - 1]␉!= 0xB8 ||␊
334␉␉ bytes[patchLocation]␉␉!= 0x04 ||␉// KERN_INVALID_ARGUMENT (0x00000004)␊
335␉␉ bytes[patchLocation + 1]␉!= 0x00 ||␉// KERN_INVALID_ARGUMENT␊
336␉␉ bytes[patchLocation + 2]␉!= 0x00 ||␉// KERN_INVALID_ARGUMENT␊
337␉␉ bytes[patchLocation + 3]␉!= 0x00)␉// KERN_INVALID_ARGUMENT␊
338␊
339␉{␊
340␉␉patchLocation++;␊
341␉}␊
342␉bytes[patchLocation] = 0x00;␉// KERN_SUCCESS;␊
343}␊
344

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