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From: Andrew Morton <akpm@osdl.org>
To: Nikita Danilov <Nikita@Namesys.COM>
Cc: linux-kernel@vger.kernel.org, ltp-list@lists.sourceforge.net,
	error27@email.com
Subject: Re: [Announce] Strace Test
Date: Thu, 19 Feb 2004 02:38:13 -0800	[thread overview]
Message-ID: <20040219023813.2d4b0ced.akpm@osdl.org> (raw)
In-Reply-To: <16436.35563.593635.277584@laputa.namesys.com>

Nikita Danilov <Nikita@Namesys.COM> wrote:
>
>  > Strace Test uses a modified version of strace 4.5.1.  
>   > Instead of printing out information about system calls, 
>   > the modified version calls the syscalls with improper 
>   > values.
> 
>  It immediately DoSes kernel by calling sys_sysctl() with huge nlen:
>  printk() consumes all CPU.

Something like this?

--- 25/kernel/sysctl.c~sysctl-nlen-check	2004-02-19 02:36:20.000000000 -0800
+++ 25-akpm/kernel/sysctl.c	2004-02-19 02:37:40.000000000 -0800
@@ -913,6 +913,9 @@ asmlinkage long sys_sysctl(struct __sysc
 
 	if (copy_from_user(&tmp, args, sizeof(tmp)))
 		return -EFAULT;
+
+	if (tmp.nlen < 0 || tmp.nlen > CTL_MAXNAME)
+		return -EINVAL;
 	
 	if (tmp.nlen != 2 || copy_from_user(name, tmp.name, sizeof(name)) ||
 	    name[0] != CTL_KERN || name[1] != KERN_VERSION) { 

_


  reply	other threads:[~2004-02-19 10:38 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-02-16  5:22 [Announce] Strace Test dan carpenter
2004-02-16  6:59 ` Anton Blanchard
2004-03-11  9:53   ` Chris Wedgwood
2004-02-16 15:46 ` [LTP] " Robert Williamson
2004-02-19 10:07 ` Nikita Danilov
2004-02-19 10:38   ` Andrew Morton [this message]
2004-02-19 10:51     ` Nikita Danilov
2004-02-19 10:59       ` Andrew Morton
2004-02-19 10:29 ` David Weinehall

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