From: admin LI <admin@hifiphile.com>
To: kernelnewbies@kernelnewbies.org
Subject: How to disable address randomization ?
Date: Thu, 13 Jan 2022 22:01:30 +0100 [thread overview]
Message-ID: <CA+GyqeZpd+x7VG_1aO5ogCsQ_=hMoDFSN16dE6739cjU_nR2dw@mail.gmail.com> (raw)
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Hi,
I'm developing a kernel module for an ARM machine, while debugging I found
addresses
printed are all randomized and useless for debugging.
To prove I was not crazy I wrote this small program:
---------------------------------
#include <linux/init.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/slab.h>
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Somebody");
MODULE_DESCRIPTION("A simple example Linux module.");
MODULE_VERSION("0.01");
static int __init example_init(void) {
uint32_t a;
uint32_t b;
uint32_t c;
uint8_t d[10];
uint8_t *e;
printk(KERN_INFO "Hello, World!\n");
printk(KERN_INFO "&a %p\n",&a);
printk(KERN_INFO "&b %p\n",&b);
printk(KERN_INFO "&c %p\n",&c);
printk(KERN_INFO "&d %p\n",d);
printk(KERN_INFO "&d[0] %p\n",&d[0]);
printk(KERN_INFO "&d[1] %p\n",&d[1]);
e = kmalloc(10, GFP_KERNEL);
printk(KERN_INFO "&e[0] %p\n",&e[0]);
printk(KERN_INFO "&e[1] %p\n",&e[1]);
kfree(e);
return 0;
}
static void __exit example_exit(void) {
printk(KERN_INFO "Goodbye, World!\n");
}
module_init(example_init);
module_exit(example_exit);
---------------------------------
And it gave me this output:
Hello, World!
&a b3f9fa31
&b 27e1c68a
&c da50d287
&d 9f9aec2b
&d[0] 9f9aec2b
&d[1] cc627580
&e[0] 98b8c9eb
&e[1] 45f248f8
Then I tested on my debian host machine which gave me the same kind of
randomized addresses.
When I search randomization the only thing I found is KASLR which I don't
think is the same thing.
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next reply other threads:[~2022-01-13 21:05 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-13 21:01 admin LI [this message]
2022-01-13 21:40 ` How to disable address randomization ? Valentin Vidić
2022-01-13 22:44 ` Jeffrey Walton
2022-01-13 23:54 ` Aruna Hewapathirane
2022-01-14 7:11 ` admin LI
2022-01-14 7:12 ` admin LI
2022-01-14 0:36 ` Chan Kim
2022-01-14 7:14 ` admin LI
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