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Properly restore protections for iOS 13 #66

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Merged
merged 1 commit into from
Aug 23, 2019
+37 −1
Merged

Properly restore protections for iOS 13 #66

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38 changes: 37 additions & 1 deletion fishhook.c
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Original file line number Diff line number Diff line change
@@ -29,6 +29,9 @@
#include <string.h>
#include <sys/mman.h>
#include <sys/types.h>
#include <mach/mach.h>
#include <mach/vm_map.h>
#include <mach/vm_region.h>
#include <mach-o/dyld.h>
#include <mach-o/loader.h>
#include <mach-o/nlist.h>
@@ -78,6 +81,27 @@ static int prepend_rebindings(struct rebindings_entry **rebindings_head,
return 0;
}

static vm_prot_t get_protection(void *sectionStart) {
mach_port_t task = mach_task_self();
vm_size_t size = 0;
vm_address_t address = (vm_address_t)sectionStart;
memory_object_name_t object;
#if __LP64__
mach_msg_type_number_t count = VM_REGION_BASIC_INFO_COUNT_64;
vm_region_basic_info_data_64_t info;
kern_return_t info_ret = vm_region_64(
task, &address, &size, VM_REGION_BASIC_INFO_64, (vm_region_info_64_t)&info, &count, &object);
#else
mach_msg_type_number_t count = VM_REGION_BASIC_INFO_COUNT;
vm_region_basic_info_data_t info;
kern_return_t info_ret = vm_region(task, &address, &size, VM_REGION_BASIC_INFO, (vm_region_info_t)&info, &count, &object);
#endif
if (info_ret == KERN_SUCCESS) {
return info.protection;
} else {
return VM_PROT_READ;
}
}
static void perform_rebinding_with_section(struct rebindings_entry *rebindings,
section_t *section,
intptr_t slide,
@@ -87,7 +111,9 @@ static void perform_rebinding_with_section(struct rebindings_entry *rebindings,
const bool isDataConst = strcmp(section->segname, "__DATA_CONST") == 0;
uint32_t *indirect_symbol_indices = indirect_symtab + section->reserved1;
void **indirect_symbol_bindings = (void **)((uintptr_t)slide + section->addr);
vm_prot_t oldProtection = VM_PROT_READ;
if (isDataConst) {
oldProtection = get_protection(rebindings);
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@swolchok why do you get protection of the page of the struct rebindings_entry?

mprotect(indirect_symbol_bindings, section->size, PROT_READ | PROT_WRITE);
}
for (uint i = 0; i < section->size / sizeof(void *); i++) {
@@ -117,7 +143,17 @@ static void perform_rebinding_with_section(struct rebindings_entry *rebindings,
symbol_loop:;
}
if (isDataConst) {
mprotect(indirect_symbol_bindings, section->size, PROT_READ);
int protection = 0;
if (oldProtection & VM_PROT_READ) {
protection |= PROT_READ;
}
if (oldProtection & VM_PROT_WRITE) {
protection |= PROT_WRITE;
}
if (oldProtection & VM_PROT_EXECUTE) {
protection |= PROT_EXEC;
}
mprotect(indirect_symbol_bindings, section->size, protection);
}
}