Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Fix crash in UIAccessibilityStatusUtility rebinding logic #194

Merged
merged 1 commit into from
Jan 25, 2024
Merged

Fix crash in UIAccessibilityStatusUtility rebinding logic #194

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
55 changes: 10 additions & 45 deletions Sources/AccessibilitySnapshot/Core/ObjC/UIAccessibilityStatusUtility.m
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -153,41 +153,15 @@ 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;
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);
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,
nlist_t *symtab,
char *strtab,
uint32_t *indirect_symtab) {
const bool isDataConst = strcmp(section->segname, SEG_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);
mprotect(indirect_symbol_bindings, section->size, PROT_READ | PROT_WRITE);
}

for (uint i = 0; i < section->size / sizeof(void *); i++) {
uint32_t symtab_index = indirect_symbol_indices[i];
if (symtab_index == INDIRECT_SYMBOL_ABS || symtab_index == INDIRECT_SYMBOL_LOCAL ||
Expand All @@ -200,33 +174,24 @@ static void perform_rebinding_with_section(struct rebindings_entry *rebindings,
struct rebindings_entry *cur = rebindings;
while (cur) {
for (uint j = 0; j < cur->rebindings_nel; j++) {
if (symbol_name_longer_than_1 &&
strcmp(&symbol_name[1], cur->rebindings[j].name) == 0) {
if (cur->rebindings[j].replaced != NULL &&
indirect_symbol_bindings[i] != cur->rebindings[j].replacement) {
if (symbol_name_longer_than_1 && strcmp(&symbol_name[1], cur->rebindings[j].name) == 0) {
if (cur->rebindings[j].replaced != NULL && indirect_symbol_bindings[i] != cur->rebindings[j].replacement) {
*(cur->rebindings[j].replaced) = indirect_symbol_bindings[i];
}
indirect_symbol_bindings[i] = cur->rebindings[j].replacement;

kern_return_t err = vm_protect(mach_task_self(), (uintptr_t)indirect_symbol_bindings, section->size, 0, VM_PROT_READ | VM_PROT_WRITE | VM_PROT_COPY);

if (err == KERN_SUCCESS) {
indirect_symbol_bindings[i] = cur->rebindings[j].replacement;
}

goto symbol_loop;
}
}
cur = cur->next;
}
symbol_loop:;
}
if (isDataConst) {
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);
}
}

static void rebind_symbols_for_image(struct rebindings_entry *rebindings,
Expand Down
Loading