linux-kernel - Re: Problem with set_memory

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Date:	Thu, 04 Feb 2010 10:42:49 +0200
From:	Oleg Kutkov <elenbert@...il.com>
To:	linux-kernel@...r.kernel.org
Subject: Re: Problem with set_memory_rw

"KAMEZAWA Hiroyuki" <kamezawa.hiroyu@...fujitsu.com 
<mailto:kamezawa.hiroyu@...fujitsu.com>> wrote:
> set_memory_rw()'s 1st argument requires virtual address.
> So, you need virtual address of the page you want.
>
>  - phys_to_virt() ... convert physical address to virtual address.
>  - virt_to_phys() ... convert virtual address to physical.
>
> Anyway, RW is vitual address mapping's attribute and not for physical.
>
> Thanks,
> -Kame   
>

Thank for answer!
But this is a very strange, because 0x0509940, i passed, - it a virtual 
memory address (i got it from System.map, this is a system call table, 
on my machine). set_memory_rw return zero, anyway. So i can't continue 
writing to memory. Maybe, system call table is much write protected, so 
i can't change attribute of memory page?
One more interesting thing:

struct page *pg;
pg = virt_to_page(addr);
unsigned long page_addr;
page_addr = (unsigned long) page_address(pg);

addr - this is my virtual address (provided by System.map)
But page_addr got another value!
What wrong?
Sorry, if my questions is to stupid.

P.S. I know, that overwriting system call table is very bad, i just 
experimenting with my own network drivers and i need to replace some 
network system calls..

Best regard,
Oleg.

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/