linux-kernel - Re: [PATCHv8 1/2] x86/vdso: add mremap hook to vm_special

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-next>] [day] [month] [year] [list]

Date:	Thu, 5 May 2016 13:52:40 +0200
From:	Ingo Molnar <mingo@...nel.org>
To:	Dmitry Safonov <dsafonov@...tuozzo.com>
Cc:	Andy Lutomirski <luto@...capital.net>,
	Ingo Molnar <mingo@...hat.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	"H. Peter Anvin" <hpa@...or.com>, X86 ML <x86@...nel.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	"linux-mm@...ck.org" <linux-mm@...ck.org>,
	Dmitry Safonov <0x7f454c46@...il.com>
Subject: Re: [PATCHv8 1/2] x86/vdso: add mremap hook to vm_special_mapping


* Dmitry Safonov <dsafonov@...tuozzo.com> wrote:

> On 04/26/2016 12:38 AM, Andy Lutomirski wrote:
> >On Mon, Apr 25, 2016 at 4:37 AM, Dmitry Safonov <dsafonov@...tuozzo.com> wrote:
> >>Add possibility for userspace 32-bit applications to move
> >>vdso mapping. Previously, when userspace app called
> >>mremap for vdso, in return path it would land on previous
> >>address of vdso page, resulting in segmentation violation.
> >>Now it lands fine and returns to userspace with remapped vdso.
> >>This will also fix context.vdso pointer for 64-bit, which does not
> >>affect the user of vdso after mremap by now, but this may change.
> >>
> >>As suggested by Andy, return EINVAL for mremap that splits vdso image.
> >>
> >>Renamed and moved text_mapping structure declaration inside
> >>map_vdso, as it used only there and now it complement
> >>vvar_mapping variable.
> >>
> >>There is still problem for remapping vdso in glibc applications:
> >>linker relocates addresses for syscalls on vdso page, so
> >>you need to relink with the new addresses. Or the next syscall
> >>through glibc may fail:
> >>   Program received signal SIGSEGV, Segmentation fault.
> >>   #0  0xf7fd9b80 in __kernel_vsyscall ()
> >>   #1  0xf7ec8238 in _exit () from /usr/lib32/libc.so.6
> >Acked-by: Andy Lutomirski <luto@...nel.org>
> >
> >Ingo, can you apply this?
> 
> Hm, so I'm not sure - should I resend those two?
> Or just ping?

Please send a clean series with updated Acked-by's, etc.

Thanks!

	Ingo