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If hooking in __DATA_CONST, make writable before trying to write #65

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Merged
merged 1 commit into from
Aug 20, 2019
+9 −0
Merged

If hooking in __DATA_CONST, make writable before trying to write #65

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9 changes: 9 additions & 0 deletions fishhook.c
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Original file line number Diff line number Diff line change
@@ -24,8 +24,10 @@
#include "fishhook.h"

#include <dlfcn.h>
#include <stdbool.h>
#include <stdlib.h>
#include <string.h>
#include <sys/mman.h>
#include <sys/types.h>
#include <mach-o/dyld.h>
#include <mach-o/loader.h>
@@ -82,8 +84,12 @@ static void perform_rebinding_with_section(struct rebindings_entry *rebindings,
nlist_t *symtab,
char *strtab,
uint32_t *indirect_symtab) {
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);
if (isDataConst) {
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 ||
@@ -110,6 +116,9 @@ static void perform_rebinding_with_section(struct rebindings_entry *rebindings,
}
symbol_loop:;
}
if (isDataConst) {
mprotect(indirect_symbol_bindings, section->size, PROT_READ);
}
}

static void rebind_symbols_for_image(struct rebindings_entry *rebindings,