linux-kernel - Re: Sparc miss chance to fix recoverable fault in copy_from

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] [day] [month] [year] [list]

Message-Id: <20090813.202925.84343745.davem@davemloft.net>
Date:	Thu, 13 Aug 2009 20:29:25 -0700 (PDT)
From:	David Miller <davem@...emloft.net>
To:	heyongli@...il.com
Cc:	linux-kernel@...r.kernel.org, sparclinux@...r.kernel.org
Subject: Re: Sparc miss chance to fix recoverable fault in copy_from_user

From: hyl <heyongli@...il.com>
Date: Fri, 14 Aug 2009 11:16:41 +0800

> console is: (access the address 0xffff fff0 )
>     SUN4V-DTLB: Error at TPC[5f2cc8], tl 1
>     SUN4V-DTLB: TPC<memcpy_user_stub+0x8/0x40>
>     SUN4V-DTLB: O7[4af23c]
>     SUN4V-DTLB: O7<probe_kernel_read+0x3c/0xa0>
>     SUN4V-DTLB: vaddr[ffffffffffffe000] ctx[0] pte[800007ffffffe743] error[2]
> 
> 
> the problem is :
> this DTLB fault can be fixed by search extable, by fall to the
> do_sparc64_fault, my draft proposal can verify this:  with this patch, this kind
> of fault is recovery, so enable copy_from_user  return error instead of halt.
> 
> in addition, it is triggered in kernel space, search the extable is mandatory .

No, that's not the problem.

The problem is that the virtual address validation done in the TLB
miss path accepts the address printed in:

>     SUN4V-DTLB: vaddr[ffffffffffffe000] ctx[0] pte[800007ffffffe743] error[2]

That's the real bug, not any of the other things you are talking
about.

Your "fix" would only paper over this problem.
--
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/