kallsyms_lookup_name fix and also added execute permission to napper.py

napper-driver/napper.c

@@ -12,12 +12,81 @@
 #include <linux/init.h>
 #include <asm/text-patching.h>
 #include <linux/kallsyms.h>
+#include <linux/kprobes.h>
 
 MODULE_LICENSE("GPL v2");
 MODULE_AUTHOR("Seunghun Han"); 
 MODULE_VERSION("1.0"); 
 MODULE_DESCRIPTION("Napper kernel module for checking a TPM vulnerability"); 
 
+//kallsyms_lookup_name workaround
+
+typedef unsigned long (*kln_p)(const char*);
+
+#define KPROBE_PRE_HANDLER(fname) static int __kprobes fname(struct kprobe *p, struct pt_regs *regs)
+
+long unsigned int kln_addr = 0;
+unsigned long (*kln_pointer)(const char* name) = NULL;
+
+static struct kprobe kp0, kp1;
+
+KPROBE_PRE_HANDLER(handler_pre0) {
+    kln_addr = (--regs->ip);
+
+    return 0;
+}
+
+KPROBE_PRE_HANDLER(handler_pre1) {
+    return 0;
+}
+
+static int do_register_kprobe(struct kprobe* kp, char* symbol_name, void* handler) {
+    int ret;
+
+    kp->symbol_name = symbol_name;
+    kp->pre_handler = handler;
+
+    ret = register_kprobe(kp);
+    if (ret < 0) {
+        pr_err("do_register_kprobe: failed to register for symbol %s, returning %d\n", symbol_name, ret);
+        return ret;
+    }
+
+    pr_info("Planted krpobe for symbol %s at %p\n", symbol_name, kp->addr);
+
+    return ret;
+}
+
+// this is the function that I have modified, as the name suggests it returns a pointer to the extracted kallsyms_lookup_name function
+kln_p get_kln_p(void) {
+    int status;
+
+    status = do_register_kprobe(&kp0, "kallsyms_lookup_name", handler_pre0);
+
+    if (status < 0) return NULL;
+
+    status = do_register_kprobe(&kp1, "kallsyms_lookup_name", handler_pre1);
+
+    if (status < 0) {
+        // cleaning initial krpobe
+        unregister_kprobe(&kp0);
+        return NULL;
+    }
+
+    unregister_kprobe(&kp0);
+    unregister_kprobe(&kp1);
+
+    pr_info("kallsyms_lookup_name address = 0x%lx\n", kln_addr);
+
+    kln_pointer = (unsigned long (*)(const char* name)) kln_addr;
+
+    return kln_pointer;
+}
+
+#define kallsyms_lookup_name(name) (get_kln_p())(name);
+
+//end kallsyms_lookup_name workaround
+
 typedef void *(*TEXT_POKE) (void *addr, const void *opcode, size_t len);
 
 TEXT_POKE g_fn_text_poke;