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From: Matthew Wilcox <willy@infradead.org>
To: "Longpeng (Mike,
	Cloud Infrastructure Service Product Dept.)"
	<longpeng2@huawei.com>
Cc: Steven Sistare <steven.sistare@oracle.com>,
	Anthony Yznaga <anthony.yznaga@oracle.com>,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	"Gonglei (Arei)" <arei.gonglei@huawei.com>
Subject: Re: [RFC PATCH 0/5] madvise MADV_DOEXEC
Date: Mon, 12 Jul 2021 02:30:18 +0100	[thread overview]
Message-ID: <YOubKmDwxMIvdAed@casper.infradead.org> (raw)
In-Reply-To: <a1dbf12e-9949-109e-122c-ba7ba609801b@huawei.com>

On Mon, Jul 12, 2021 at 09:05:45AM +0800, Longpeng (Mike, Cloud Infrastructure Service Product Dept.) wrote:
> Let me describe my use case more clearly (just ignore if you're not interested
> in it):
> 
> 1. Prog A mmap() 4GB memory (anon or file-mapping), suppose the allocated VA
> range is [0x40000000,0x140000000)
> 
> 2. Prog A specifies [0x48000000,0x50000000) and [0x80000000,0x100000000) will be
> shared by its child.
> 
> 3. Prog A fork() Prog B and then Prog B exec() a new ELF binary.
> 
> 4. Prog B notice the shared ranges (e.g. by input parameters or ...) and remap
> them to a continuous VA range.

This is dangerous.  There must be an active step for Prog B to accept
Prog A's ranges into its address space.  Otherwise Prog A could almost
completely fill Prog B's address space and so control where Prog B
places its mappings.  It could also provoke a latent bug in Prog B
if it doesn't handle address space exhaustion gracefully.

I had a proposal to handle this.  Would it meet your requirements?
https://lore.kernel.org/lkml/20200730152250.GG23808@casper.infradead.org/


  reply	other threads:[~2021-07-12  1:30 UTC|newest]

Thread overview: 74+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-27 17:11 [RFC PATCH 0/5] madvise MADV_DOEXEC Anthony Yznaga
2020-07-27 17:07 ` Eric W. Biederman
2020-07-27 18:00   ` Steven Sistare
2020-07-28 13:40     ` Christian Brauner
2020-07-27 17:11 ` [RFC PATCH 1/5] elf: reintroduce using MAP_FIXED_NOREPLACE for elf executable mappings Anthony Yznaga
2020-07-27 17:11 ` [RFC PATCH 2/5] mm: do not assume only the stack vma exists in setup_arg_pages() Anthony Yznaga
2020-07-27 17:11 ` [RFC PATCH 3/5] mm: introduce VM_EXEC_KEEP Anthony Yznaga
2020-07-28 13:38   ` Eric W. Biederman
2020-07-28 17:44     ` Anthony Yznaga
2020-07-29 13:52   ` Kirill A. Shutemov
2020-07-29 23:20     ` Anthony Yznaga
2020-07-27 17:11 ` [RFC PATCH 4/5] exec, elf: require opt-in for accepting preserved mem Anthony Yznaga
2020-07-27 17:11 ` [RFC PATCH 5/5] mm: introduce MADV_DOEXEC Anthony Yznaga
2020-07-28 13:22   ` Kirill Tkhai
2020-07-28 14:06     ` Steven Sistare
2020-07-28 11:34 ` [RFC PATCH 0/5] madvise MADV_DOEXEC Kirill Tkhai
2020-07-28 17:28   ` Anthony Yznaga
2020-07-28 14:23 ` Andy Lutomirski
2020-07-28 14:30   ` Steven Sistare
2020-07-30 15:22 ` Matthew Wilcox
2020-07-30 15:27   ` Christian Brauner
2020-07-30 15:34     ` Matthew Wilcox
2020-07-30 15:54       ` Christian Brauner
2020-07-31  9:12     ` Stefan Hajnoczi
2020-07-30 15:59   ` Steven Sistare
2020-07-30 17:12     ` Matthew Wilcox
2020-07-30 17:35       ` Steven Sistare
2020-07-30 17:49         ` Matthew Wilcox
2020-07-30 18:27           ` Steven Sistare
2020-07-30 21:58             ` Eric W. Biederman
2020-07-31 14:57               ` Steven Sistare
2020-07-31 15:27                 ` Matthew Wilcox
2020-07-31 16:11                   ` Steven Sistare
2020-07-31 16:56                     ` Jason Gunthorpe
2020-07-31 17:15                       ` Steven Sistare
2020-07-31 17:48                         ` Jason Gunthorpe
2020-07-31 17:55                           ` Steven Sistare
2020-07-31 17:23                     ` Matthew Wilcox
2020-08-03 15:28                 ` Eric W. Biederman
2020-08-03 15:42                   ` James Bottomley
2020-08-03 20:03                     ` Steven Sistare
     [not found]                     ` <9371b8272fd84280ae40b409b260bab3@AcuMS.aculab.com>
2020-08-04 11:13                       ` Matthew Wilcox
2020-08-03 19:29                   ` Steven Sistare
2020-07-31 19:41 ` Steven Sistare
2021-07-08  9:52 ` Longpeng (Mike, Cloud Infrastructure Service Product Dept.)
2021-07-08 12:48   ` Steven Sistare
2021-07-12  1:05     ` Longpeng (Mike, Cloud Infrastructure Service Product Dept.)
2021-07-12  1:30       ` Matthew Wilcox [this message]
2021-07-13  0:57         ` Longpeng (Mike, Cloud Infrastructure Service Product Dept.)
2021-08-13 19:49           ` Khalid Aziz
2021-08-14 20:07             ` David Laight
2021-08-16  0:26               ` Longpeng (Mike, Cloud Infrastructure Service Product Dept.)
2021-08-16  8:07                 ` David Laight
2021-08-16  6:54             ` Longpeng (Mike, Cloud Infrastructure Service Product Dept.)
2021-08-16  8:02             ` David Hildenbrand
2021-08-16 12:07               ` Matthew Wilcox
2021-08-16 12:20                 ` David Hildenbrand
2021-08-16 12:42                   ` David Hildenbrand
2021-08-16 12:46                   ` Matthew Wilcox
2021-08-16 13:24                     ` David Hildenbrand
2021-08-16 13:32                       ` Matthew Wilcox
2021-08-16 14:10                         ` David Hildenbrand
2021-08-16 14:27                           ` Matthew Wilcox
2021-08-16 14:33                             ` David Hildenbrand
2021-08-16 14:40                               ` Matthew Wilcox
2021-08-16 15:01                                 ` David Hildenbrand
2021-08-16 15:59                                   ` Matthew Wilcox
2021-08-16 16:06                                     ` Khalid Aziz
2021-08-16 16:15                                       ` Matthew Wilcox
2021-08-16 16:13                                     ` David Hildenbrand
2021-08-16 12:27                 ` [private] " David Hildenbrand
2021-08-16 12:30                   ` David Hildenbrand
2021-08-17  0:47                 ` Longpeng (Mike, Cloud Infrastructure Service Product Dept.)
2021-08-17  0:55                   ` Matthew Wilcox

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