linux-kernel - Re: [RFC c/r 4/4] c/r: prctl: Extend PR_SET_MM to set up more mm

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]

Date:	Fri, 27 Jan 2012 15:28:51 -0500
From:	KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>
To:	keescook@...omium.org
CC:	gorcunov@...nvz.org, linux-kernel@...r.kernel.org,
	akpm@...ux-foundation.org, ebiederm@...ssion.com, xemul@...nvz.org,
	mtk.manpages@...il.com, tj@...nel.org, avagin@...nvz.org,
	serge.hallyn@...onical.com, xemul@...allels.com,
	segoon@...nwall.com, kamezawa.hiroyu@...fujitsu.com
Subject: Re: [RFC c/r 4/4] c/r: prctl: Extend PR_SET_MM to set up more mm_struct
 entries

>> +
>> +       case PR_SET_MM_AUXV:
>> +               if (arg4 > sizeof(mm->saved_auxv))
>> +                       goto out;
>> +               up_read(&mm->mmap_sem);
>> +
>> +               error = -EFAULT;
>> +               if (!copy_from_user(mm->saved_auxv, (const void __user *)addr, arg4))
>> +                       error = 0;
>> +
>> +               return error;
> 
> Is the mmap_sem released here because of the copy_from_user()? Is it
> still safe to write to saved_auxv?

Sure. It's unsafe.

--
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/