linux-kernel - Re: [PATCH 1/2] sched: Add helper for task stack page overrun checking

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

Message-ID: <20140904150234.GA6480@redhat.com>
Date:	Thu, 4 Sep 2014 17:02:34 +0200
From:	Oleg Nesterov <oleg@...hat.com>
To:	Aaron Tomlin <atomlin@...hat.com>
Cc:	peterz@...radead.org, mingo@...hat.com, dzickus@...hat.com,
	bmr@...hat.com, jcastillo@...hat.com, pzijlstr@...hat.com,
	riel@...hat.com, linux-kernel@...r.kernel.org, tglx@...utronix.de,
	x86@...nel.org, rostedt@...dmis.org, hannes@...xchg.org,
	aneesh.kumar@...ux.vnet.ibm.com, akpm@...ux-foundation.org,
	linuxppc-dev@...ts.ozlabs.org, minchan@...nel.org
Subject: Re: [PATCH 1/2] sched: Add helper for task stack page overrun
	checking

On 09/04, Aaron Tomlin wrote:
>
> +#define task_stack_end_corrupted(task) \
> +		(*(end_of_stack(task)) != STACK_END_MAGIC)

and it is always used along with "tsk != init_task".

But why we exclude swapper/0? Can't we add

	end_of_stack(current) = STACK_END_MAGIC;

somewhere at the start of start_kernel() ?

If not, perhaps this new helper should check "task != &init_task"
itself so that we can simplify its users?

Oleg.

>  
>  static inline int object_is_on_stack(void *obj)
>  {
> diff --git a/kernel/trace/trace_stack.c b/kernel/trace/trace_stack.c
> index 8a4e5cb..06c7390 100644
> --- a/kernel/trace/trace_stack.c
> +++ b/kernel/trace/trace_stack.c
> @@ -13,7 +13,6 @@
>  #include <linux/sysctl.h>
>  #include <linux/init.h>
>  #include <linux/fs.h>
> -#include <linux/magic.h>
>  
>  #include <asm/setup.h>
>  
> @@ -171,8 +170,8 @@ check_stack(unsigned long ip, unsigned long *stack)
>  			i++;
>  	}
>  
> -	if ((current != &init_task &&
> -		*(end_of_stack(current)) != STACK_END_MAGIC)) {
> +	if (current != &init_task &&
> +		task_stack_end_corrupted(current)) {
>  		print_max_stack();
>  		BUG();
>  	}
> -- 
> 1.9.3
> 

--
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/