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Message-ID: <CACT4Y+a_J1sjL352sY=+6paZDg2-4V9UPa8t3XBNeZfYw_ZHWA@mail.gmail.com>
Date: Tue, 11 Dec 2018 11:16:20 +0100
From: Dmitry Vyukov <dvyukov@...gle.com>
To: Andrew Morton <akpm@...ux-foundation.org>,
Jens Axboe <axboe@...nel.dk>, linux-block@...r.kernel.org,
LKML <linux-kernel@...r.kernel.org>
Cc: Andrey Ryabinin <aryabinin@...tuozzo.com>,
Alexander Potapenko <glider@...gle.com>,
bugzilla-daemon@...zilla.kernel.org,
kasan-dev <kasan-dev@...glegroups.com>, jaguo2014@...look.com
Subject: Re: [Bug 201949] New: KASAN: use-after-free Read in __handle_mm_fault
On Tue, Dec 11, 2018 at 12:45 AM Andrew Morton
<akpm@...ux-foundation.org> wrote:
>
> (switched to email. Please respond via emailed reply-to-all, not via the
> bugzilla web interface).
Looking at the reproducer this looks like a bug in sg ioctl.
+block/scsi_ioctl.c maintainers
> On Mon, 10 Dec 2018 10:56:31 +0000 bugzilla-daemon@...zilla.kernel.org wrote:
>
> > https://bugzilla.kernel.org/show_bug.cgi?id=201949
> >
> > Bug ID: 201949
> > Summary: KASAN: use-after-free Read in __handle_mm_fault
> > Product: Memory Management
> > Version: 2.5
> > Kernel Version: 4.19-rc2,4.20-rc5,4.20-rc6
> > Hardware: All
> > OS: Linux
> > Tree: Mainline
> > Status: NEW
> > Severity: normal
> > Priority: P1
> > Component: Other
> > Assignee: akpm@...ux-foundation.org
> > Reporter: jaguo2014@...look.com
> > Regression: No
> >
> > Created attachment 279915
> > --> https://bugzilla.kernel.org/attachment.cgi?id=279915&action=edit
> > poc.c
> >
> > Syzkaller hit 'KASAN: use-after-free Read in __handle_mm_fault' bug.
> >
> > ==================================================================
> > BUG: KASAN: use-after-free in handle_pte_fault mm/memory.c:3744 [inline]
> > BUG: KASAN: use-after-free in __handle_mm_fault+0x1b5d/0x1d20 mm/memory.c:3889
> > Read of size 8 at addr ffff888000048008 by task syz-executor666/2067
> >
> > CPU: 0 PID: 2067 Comm: syz-executor666 Not tainted 4.20.0-rc5+ #1
> > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 0.5.1 01/01/2011
> > Call Trace:
> > __dump_stack lib/dump_stack.c:77 [inline]
> > dump_stack+0x75/0xae lib/dump_stack.c:113
> > print_address_description+0x65/0x270 mm/kasan/report.c:256
> > kasan_report_error mm/kasan/report.c:354 [inline]
> > kasan_report+0x25b/0x380 mm/kasan/report.c:412
> > handle_pte_fault mm/memory.c:3744 [inline]
> > __handle_mm_fault+0x1b5d/0x1d20 mm/memory.c:3889
> > handle_mm_fault+0xfc/0x350 mm/memory.c:3926
> > do_user_addr_fault arch/x86/mm/fault.c:1423 [inline]
> > __do_page_fault+0x4f4/0xaa0 arch/x86/mm/fault.c:1489
> > async_page_fault+0x1e/0x30 arch/x86/entry/entry_64.S:1142
> > RIP: 0033:0x4014fd
> > Code: Bad RIP value.
> > RSP: 002b:00007ffdaac075f0 EFLAGS: 00010246
> > RAX: 0000000000000000 RBX: 00007ffdaac07790 RCX: 00007f6df4bee2f0
> > RDX: 0000000000000001 RSI: 00007f6df4bea270 RDI: 00007f6df4e08ae0
> > RBP: 0000000000000000 R08: 00007f6df4e08800 R09: 00007f6df4bea270
> > R10: 00007f6df4e08800 R11: 0000000000000202 R12: 0000000000000000
> > R13: 00007ffdaac07920 R14: 0000000000000000 R15: 0000000000000000
> >
> > The buggy address belongs to the page:
> > page:ffffea0000001200 count:0 mapcount:0 mapping:0000000000000000 index:0x0
> > flags: 0x0()
> > raw: 0000000000000000 ffffea0000001208 ffffea0000001208 0000000000000000
> > raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
> > page dumped because: kasan: bad access detected
> >
> > Memory state around the buggy address:
> > ffff888000047f00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
> > ffff888000047f80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
> > >ffff888000048000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
> > ^
> > ffff888000048080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
> > ffff888000048100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
> > ==================================================================
> >
> >
> > Syzkaller reproducer:
> > # {Threaded:false Collide:false Repeat:true RepeatTimes:0 Procs:8 Sandbox:
> > Fault:false FaultCall:-1 FaultNth:0 EnableTun:false UseTmpDir:true
> > EnableCgroups:false EnableNetdev:false ResetNet:false HandleSegv:true
> > Repro:false Trace:false}
> > r0 = syz_open_dev$sg(&(0x7f0000000180)='/dev/sg#\x00', 0x0, 0x0)
> > ioctl$SCSI_IOCTL_SEND_COMMAND(r0, 0x1, &(0x7f0000000080)={0x1, 0x0, 0x8, "ae"})
> >
> > --
> > You are receiving this mail because:
> > You are the assignee for the bug.
>
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