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

Jump to bottom

If hooking in __DATA_CONST/__AUTH_CONST, promise writable before trying to write #84

Open
wants to merge 2 commits into
base: main
Choose a base branch
from
Open

If hooking in __DATA_CONST/__AUTH_CONST, promise writable before trying to write #84

Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
2559bcc
If hooking in __DATA_CONST/__AUTH_CONST, promise writable before tryi…
Feb 28, 2021
9000c7d
set memory protection in multithread
Mar 2, 2021
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Jump to
Jump to file
Failed to load files.
Diff view
Diff view
28 changes: 21 additions & 7 deletions fishhook.c
View file
Open in desktop
Expand Up @@ -35,6 +35,7 @@
#include <mach-o/dyld.h>
#include <mach-o/loader.h>
#include <mach-o/nlist.h>
#include <pthread.h>

#ifdef __LP64__
typedef struct mach_header_64 mach_header_t;
Expand All @@ -54,13 +55,18 @@ typedef struct nlist nlist_t;
#define SEG_DATA_CONST "__DATA_CONST"
#endif

#ifndef SEG_AUTH_CONST
#define SEG_AUTH_CONST "__AUTH_CONST"
#endif

struct rebindings_entry {
struct rebinding *rebindings;
size_t rebindings_nel;
struct rebindings_entry *next;
};

static struct rebindings_entry *_rebindings_head;
static pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;

static int prepend_rebindings(struct rebindings_entry **rebindings_head,
struct rebinding rebindings[],
Expand Down Expand Up @@ -109,17 +115,23 @@ static void perform_rebinding_with_section(struct rebindings_entry *rebindings,
char *strtab,
uint32_t *indirect_symtab) {
const bool isDataConst = strcmp(section->segname, SEG_DATA_CONST) == 0;
const bool isAuthConst = strcmp(section->segname, SEG_AUTH_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);
vm_size_t trunc_address = (vm_size_t)indirect_symbol_bindings;
vm_size_t trunc_size = 0;
if (isDataConst || isAuthConst) {
trunc_address = trunc_page((vm_size_t)indirect_symbol_bindings);
trunc_size =(vm_size_t)indirect_symbol_bindings -trunc_address;
pthread_mutex_lock(&mutex);
oldProtection = get_protection((void *)trunc_address);
mprotect((void *)trunc_address, section->size+trunc_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 ||
symtab_index == (INDIRECT_SYMBOL_LOCAL | INDIRECT_SYMBOL_ABS)) {
symtab_index == (INDIRECT_SYMBOL_LOCAL | INDIRECT_SYMBOL_ABS)) {
continue;
}
uint32_t strtab_offset = symtab[symtab_index].n_un.n_strx;
Expand All @@ -142,7 +154,7 @@ static void perform_rebinding_with_section(struct rebindings_entry *rebindings,
}
symbol_loop:;
}
if (isDataConst) {
if (isDataConst || isAuthConst) {
int protection = 0;
if (oldProtection & VM_PROT_READ) {
protection |= PROT_READ;
Expand All @@ -153,7 +165,8 @@ static void perform_rebinding_with_section(struct rebindings_entry *rebindings,
if (oldProtection & VM_PROT_EXECUTE) {
protection |= PROT_EXEC;
}
mprotect(indirect_symbol_bindings, section->size, protection);
mprotect((void *)trunc_address, section->size+trunc_size, protection);
pthread_mutex_unlock(&mutex);
}
}

Expand Down Expand Up @@ -202,7 +215,8 @@ static void rebind_symbols_for_image(struct rebindings_entry *rebindings,
cur_seg_cmd = (segment_command_t *)cur;
if (cur_seg_cmd->cmd == LC_SEGMENT_ARCH_DEPENDENT) {
if (strcmp(cur_seg_cmd->segname, SEG_DATA) != 0 &&
strcmp(cur_seg_cmd->segname, SEG_DATA_CONST) != 0) {
strcmp(cur_seg_cmd->segname, SEG_DATA_CONST) != 0 &&
strcmp(cur_seg_cmd->segname, SEG_AUTH_CONST) != 0) {
continue;
}
for (uint j = 0; j < cur_seg_cmd->nsects; j++) {
Expand Down