Is there any way to obtain a downloadable version of something executable
from syzbot that demonstrates the errors encountered?
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Don't be discouraged!
So, if you only read the code, it may appear to you that "in the small" you
are understanding the code. But, the possible states and paths are a large
combinatorial, and lots of things can happen at runtime that you will not
be able to predict, even after only reading the cod
47 PM, "Greg KH" wrote:
> On Thu, Nov 24, 2016 at 01:05:47PM -0500, Kenneth Adam Miller wrote:
> > So, I ran perf on my host and it came back far more true. The top
> consumers of
> > time were all atomics and some function called sse3, which I believe is
> a super
>
kernel
as designed and it used additional extensions and features.
I just thought of something-what if there is some kind of page size
difference between my host and my Linux kernel causing the performance
problems?
On Nov 24, 2016 11:33 AM, "Kenneth Adam Miller"
wrote:
>
> On Thu,
On Nov 24, 2016 2:18 AM, "Greg KH" wrote:
>
> On Thu, Nov 24, 2016 at 02:01:41AM -0500, Kenneth Adam Miller wrote:
> > Hello,
> >
> >
> > I have a scheduler issue in two different respects:
> >
> > 1) I have a process that is supposed to tight l
On Thu, Nov 24, 2016 at 11:13 AM, Greg KH wrote:
> On Thu, Nov 24, 2016 at 10:31:18AM -0500, Kenneth Adam Miller wrote:
>> On Nov 24, 2016 2:18 AM, "Greg KH" wrote:
>> >
>> > On Thu, Nov 24, 2016 at 02:01:41AM -0500, Kenneth Adam Miller wrote:
>&g
Hello,
I have a scheduler issue in two different respects:
1) I have a process that is supposed to tight loop, and it is being
given very very little time on the system. I don't want that - I want
those who would use the processor to be given the resources to run as
fast as they each can.
2) I
Oh! It's just a particular memory addressed, and that's what is being
memory mapped into user land. Then I could just write a value in the
kernel land, just as I would from the user land, to the address that
is being memory mapped in. I should just read the device spec better
and test how to write
Hello,
I'm trying to author a driver that communicates over shared memory
within the kernel land between concurrent userland processes. I'm
using this as a base:
https://github.com/henning-schild/ivshmem-guest-code/blob/master/kernel_module/uio/uio_ivshmem.c
I've been able to build it and to ins
I will check that out, thanks!
On Wed, Oct 19, 2016 at 1:06 PM, Daniel. wrote:
> Did you see this? http://fedoraproject.org/wiki/Features/VirtioSerial
>
> Regards,
>
> 2016-10-19 14:24 GMT-02:00 Kenneth Adam Miller :
>> That doesn't work for our use case. We have sp
That doesn't work for our use case. We have special hardware for our use
case.
On Oct 19, 2016 12:21 PM, "Daniel." wrote:
> Why not use networking?
>
> 2016-10-19 8:53 GMT-02:00 Kenneth Adam Miller >:
> > So, we can use qemu within our development system her
So, we can use qemu within our development system here, but the
problem is we have something that is a bit specialized in that the
machines talk to one another over a special interface. It's a bit like
named pipes, and to our applications, named pipes are a sufficient
interface to test over.
In a
5, 2016 2:29 AM, "Martin Kletzander" wrote:
> On Tue, Oct 04, 2016 at 05:05:57PM +0200, Greg KH wrote:
>
>> On Tue, Oct 04, 2016 at 10:58:16AM -0400, Kenneth Adam Miller wrote:
>>
>>> I have a character device that I am calling write on and which is
>>> s
I have a character device that I am calling write on and which is
succeeding, but which is repeatedly executing. I have hard coded the return
value to one, so I don't think the userland standard library is retrying
but I could be wrong. Can anybody tell me why write would be re-executed by
the kern
On Mon, Mar 7, 2016 at 4:49 PM, wrote:
> On Mon, 07 Mar 2016 16:08:01 -0500, Kenneth Adam Miller said:
>
> > Can't release it. It looks a lot like this though:
>
> Note that you're going to have a *really* hard time shipping hardware
> with a legal Linux driver you
On Mon, Mar 7, 2016 at 3:53 PM, Greg KH wrote:
> On Mon, Mar 07, 2016 at 03:37:24PM -0500, Kenneth Adam Miller wrote:
> >
> >
> > On Mon, Mar 7, 2016 at 3:29 PM, Greg KH wrote:
> >
> > On Mon, Mar 07, 2016 at 03:21:44PM -0500, Kenneth Adam Miller wrote:
>
On Mon, Mar 7, 2016 at 3:29 PM, Greg KH wrote:
> On Mon, Mar 07, 2016 at 03:21:44PM -0500, Kenneth Adam Miller wrote:
> >
> >
> > On Mon, Mar 7, 2016 at 3:17 PM, Greg KH wrote:
> >
> > On Mon, Mar 07, 2016 at 03:00:50PM -0500, Kenneth Adam Miller wrot
On Mon, Mar 7, 2016 at 3:17 PM, Greg KH wrote:
> On Mon, Mar 07, 2016 at 03:00:50PM -0500, Kenneth Adam Miller wrote:
> > I have a driver that manages three sets of identical data structures that
> > differ only in address values. Currently, I pray that the device file to
>
Actually, I just realized that there is probably a way to look up the
character device name with the file* that is passed in with the mmap call.
Can anybody say how?
On Mon, Mar 7, 2016 at 3:00 PM, Kenneth Adam Miller <
kennethadammil...@gmail.com> wrote:
> I have a driver that mana
I have a driver that manages three sets of identical data structures that
differ only in address values. Currently, I pray that the device file to
which I have callbacks mapped for the driver gets called sequentially,
because there are pairs of mmap's that need to be made. I know that this
isn't th
Those are the popular three, but the documentation provided by kernel
authors themselves as well as source code is also expected.
Lastly, semantics of the machine are often a required read. The intel
manual might be something that belongs on your list, if you want to truly
understand.
But no book
Is there a guidance anywhere? I know my question is simple and
straightforward, but I've looked around a bit and I can't find a direct way
to statically build a kernel module into the kernel.
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Astonishing. I changed my non-C based binary to remove PROT_READ, and I
found that the mmap test completed successfully! Now I just have to figure
out how to edit the binary headers to remove the READ_IMPLIES_EXEC option
and then test it.
On Sat, Jan 16, 2016 at 1:33 PM, Kenneth Adam Miller
The particular non-C binary that I'm using is rust with musl support, so
that I can statically compile the binary in order to eliminate all library
dependencies and then run it on a buildroot based linux.
On Sat, Jan 16, 2016 at 1:32 PM, Kenneth Adam Miller <
kennethadammil...@gmail.co
Wait, are you assuming that I'm using the latest kernel? Because I'm using
3.14.56...
On Sat, Jan 16, 2016 at 1:31 PM, Mike Krinkin wrote:
> On Sat, Jan 16, 2016 at 01:16:42PM -0500, Kenneth Adam Miller wrote:
> > Ok, so you think that the format of the binary would influenc
iminate library
dependency issues between my host machine and the target machine. I had no
idea that settings like this would carry over to my task at hand.
On Sat, Jan 16, 2016 at 1:08 PM, Mike Krinkin wrote:
> On Sat, Jan 16, 2016 at 12:45:17PM -0500, Kenneth Adam Miller wrote:
> > I got the s
le or any type of binary that's not using my device file?
On Thu, Jan 14, 2016 at 12:28 PM, Kenneth Adam Miller <
kennethadammil...@gmail.com> wrote:
>
>
> On Thu, Jan 14, 2016 at 12:00 PM, Mike Krinkin
> wrote:
>
>> Hi, i have a couple of questions to clarify, i
On Thu, Jan 14, 2016 at 12:00 PM, Mike Krinkin
wrote:
> Hi, i have a couple of questions to clarify, if you don't mind
>
> On Thu, Jan 14, 2016 at 11:04:28AM -0500, Kenneth Adam Miller wrote:
> > I have a custom drive and userland program pair that I'm using for a very
&
In fact, it's being set to 0xff exactly, not just the VM_EXEC flag being
set. vma->vm_flags & VM_EXEC resolves true, because vma->vm_flags is 0xff
On Thu, Jan 14, 2016 at 11:04 AM, Kenneth Adam Miller <
kennethadammil...@gmail.com> wrote:
> I have a custom drive and us
I have a custom drive and userland program pair that I'm using for a very
special use case at my workplace where we are mapping specific physical
address ranges into userland memory with a mmap callback. Everything works
together well with a C userland program that calls into our driver's ioctl
and
In this case, have you tried reading and writing to the memory segment
being mmap'd from userland?
Here's an example mmap'ing device driver if you need to see that:
https://github.com/claudioscordino/mmap_alloc
On Tue, Jan 12, 2016 at 6:10 PM, Jethro Beekman wrote:
> I'm writing a device driver
On Fri, Dec 18, 2015 at 9:20 AM, Henry Gomersall <
henry.gomers...@smartacoustics.co.uk> wrote:
> On 18/12/15 14:15, Kenneth Adam Miller wrote:
>
>
> On Fri, Dec 18, 2015 at 7:05 AM, Henry Gomersall <
> henry.gomers...@smartacoustics.co.uk> wrote:
>
>> On 17/12
On Fri, Dec 18, 2015 at 7:05 AM, Henry Gomersall <
henry.gomers...@smartacoustics.co.uk> wrote:
> On 17/12/15 21:35, Kenneth Adam Miller wrote:
>
> Generally uio_dmem_genirq.c builds on top of uio.c, which provides a
> common module basis for isolating code common to the other
So, previously I think I misunderstood how to use uio_dmem_genirq. Let me
explain the way I think it currently works (bare with me, I departed from
looking at this driver after only about a week of looking at it):
Generally uio_dmem_genirq.c builds on top of uio.c, which provides a common
module b
On Thu, Oct 22, 2015 at 3:38 PM, Jeff Haran wrote:
>
>
>
>
> *From:* kernelnewbies-boun...@kernelnewbies.org [mailto:
> kernelnewbies-boun...@kernelnewbies.org] *On Behalf Of *Kenneth Adam
> Miller
> *Sent:* Thursday, October 22, 2015 12:14 PM
> *To:* Kernelnewbies
>
So, previously it was discussed that /dev/mem could be used to mmap a
specific hardware memory into a process. Now I need to unit test some
userland code that does exactly that, but I need to make sure that the unit
test selects a small page that is always free in kernel land. How can I
query mem t
On Tue, Oct 20, 2015 at 8:43 PM, Greg KH wrote:
> On Tue, Oct 20, 2015 at 08:28:20PM -0400, Kenneth Adam Miller wrote:
> > On Tue, Oct 20, 2015 at 8:17 PM, Greg KH wrote:
> > On Tue, Oct 20, 2015 at 07:40:37PM -0400, Kenneth Adam Miller wrote:
> > > I didn't
On Tue, Oct 20, 2015 at 8:17 PM, Greg KH wrote:
> On Tue, Oct 20, 2015 at 07:40:37PM -0400, Kenneth Adam Miller wrote:
> >
> > On Tue, Oct 20, 2015 at 6:54 PM, Greg KH wrote:
> >
> > On Tue, Oct 20, 2015 at 11:58:21AM -0400, Kenneth Adam Miller wrote:
> >
On Tue, Oct 20, 2015 at 6:54 PM, Greg KH wrote:
> On Tue, Oct 20, 2015 at 11:58:21AM -0400, Kenneth Adam Miller wrote:
> > So I'm building a uio kernel driver with buildroot, and I've gotten the
> driver
> > to compile, installed it and can insmod it in the fi
Thanks! To anyone else that might know the answer thanks also (in advance)
:D
On Tue, Oct 20, 2015 at 5:56 PM, Mandeep Sandhu wrote:
> >> I'm on linux kernel version 3.14, and I followed the guide here:
> >>
> >> https://www.kernel.org/doc/htmldocs/uio-howto/userspace_driver.html
> >>
> >> And i
n uio driver and rely on
the services or functions that these provide. But it doesn't explicitly say
that anywhere in the guide that I read; if this were the case, why wouldn't
it?
On Tue, Oct 20, 2015 at 11:58 AM, Kenneth Adam Miller <
kennethadammil...@gmail.com> wrote:
> So I
So I'm building a uio kernel driver with buildroot, and I've gotten the
driver to compile, installed it and can insmod it in the final buildroot
target after booting the image with QEMU.
I'm on linux kernel version 3.14, and I followed the guide here:
https://www.kernel.org/doc/htmldocs/uio-howto
Have you looked at the uio driver examples?
Also, LDD3 may be old, but the API is at least still relevant. The
explanation is too long to include here, but the book is free :D
On Thu, Oct 15, 2015 at 11:53 PM, sahlot arvind wrote:
> Hi,
>
> Is there an API kernel exposes to use for a driver in
issue, and I can use ring buffers for that.
On Wed, Oct 7, 2015 at 1:02 PM, Greg KH wrote:
> On Tue, Oct 06, 2015 at 10:46:49AM -0400, Kenneth Adam Miller wrote:
> > Let me be more precise in general to the overall original question:
> >
> > I want a userland process tha
On Tue, Oct 6, 2015 at 11:04 AM, Yann Droneaud wrote:
> Hi,
>
> Le mardi 06 octobre 2015 à 10:46 -0400, Kenneth Adam Miller a écrit :
> > Let me be more precise in general to the overall original question:
> >
> > I want a userland process that I designate to only us
t 10:41 AM, Kenneth Adam Miller <
kennethadammil...@gmail.com> wrote:
>
> On Tue, Oct 6, 2015 at 10:32 AM, Yann Droneaud
> wrote:
>
>> Le mardi 06 octobre 2015 à 10:13 -0400, Kenneth Adam Miller a écrit :
>> >
>> >
>> > On Tue, Oct 6, 2015 at 9:58 A
On Tue, Oct 6, 2015 at 10:32 AM, Yann Droneaud wrote:
> Le mardi 06 octobre 2015 à 10:13 -0400, Kenneth Adam Miller a écrit :
> >
> >
> > On Tue, Oct 6, 2015 at 9:58 AM, Yann Droneaud
> > wrote:
> > > Le mardi 06 octobre 2015 à 09:26 -0400, Kenneth Adam Mill
On Tue, Oct 6, 2015 at 9:58 AM, Yann Droneaud wrote:
> Le mardi 06 octobre 2015 à 09:26 -0400, Kenneth Adam Miller a écrit :
>
> > Any body know about the issue of assigning a process a region of
> > physical memory to use for it's malloc and free? I'd like to ju
On Tue, Oct 6, 2015 at 9:57 AM, Greg KH wrote:
> On Tue, Oct 06, 2015 at 09:26:23AM -0400, Kenneth Adam Miller wrote:
> > No, I didn't try it. I just wanted to ask before I got started. Thanks
> that
> > answers everything.
> >
> > Any body know about the issue
ioctl, and then once that's done it
gets all it's memory from a specific region.
On Tue, Oct 6, 2015 at 1:21 AM, Greg KH wrote:
> On Mon, Oct 05, 2015 at 07:07:51PM -0400, Kenneth Adam Miller wrote:
> > So, I'm reading about UIO devices and user processes for mapping memo
So, I'm reading about UIO devices and user processes for mapping memory
into userland, and basically I have just a couple questions:
What happens when a userland processes has allocated some resource from a
driver that is facilitating UIO, but then subsequently crashes? I'd like to
know that the d
I'm pretty sure that exchanging ownership of memory pages between the
kernel and userland is a really huge no-go for security as well. If you do
that, you've implicitly given the user control of the memory map table
contents, so you have to think like a malicious abuser of your api would.
Copy from
You are right, and thank you for bringing this to the mailing list to be
sure about it.
There are several catastrophic vulnerabilities I can see waiting to happen.
First, you should be sure that the pointer that they passed in is checked,
as in the pointer to the buffer should only reside in the
you could use that facility of the monitor to retain the setting.
On Wed, Aug 26, 2015 at 2:16 PM, Umair Khan wrote:
>
>
> On Wed, Aug 26, 2015 at 11:21 PM, Kenneth Adam Miller <
> kennethadammil...@gmail.com> wrote:
>
>> Well, it's probably worth doing for th
Well, it's probably worth doing for the sake of your learning. However, if
you are going to get into the source, I think it's highly likely that you
are going to see that the driver provides such a feature to userspace code
through means of an ioctl, and in that case, you will probably be able to
s
Suppose I want to do something analogous to C++'s new in userspace. But
instead, I want an entirely new page table to be constructed at the
location of my choosing. In addition, I want a specific region for that
page table to manage, and this requires that this region no longer be
available to the
18/2015 08:30 PM, Kenneth Adam Miller wrote:
> > | "this is not a rational approach"
> >
> > I'm very strongly confident the approach of achieving stronger guarantees
>
>
> Off topic
>
> ___
> Ker
get, so I didn't intend to be
snarky.
On Tue, Aug 18, 2015 at 6:27 PM, Ruben Safir wrote:
> On 08/18/2015 09:25 AM, Kenneth Adam Miller wrote:
> > Ok- so I know that C is the defacto standard for kernel development.
>
>
> That about sums it up. did you have some question
t; >
> > There are others out there such as coverity scan, coccinelle, etc.
> >
> > [1] https://www.kernel.org/doc/Documentation/kmemleak.txt
> >
> > []'s
> >
> >
> > On Tue, Aug 18, 2015 at 10:45 AM, Kenneth Adam Miller
> > wrote:
> >>
can also uses Sparse in kernel for static analyze purpose.
>
> There are others out there such as coverity scan, coccinelle, etc.
>
> [1] https://www.kernel.org/doc/Documentation/kmemleak.txt
>
> []'s
>
>
> On Tue, Aug 18, 2015 at 10:45 AM, Kenneth Adam Miller
>
nism to make kernel code harder to break.
On Tue, Aug 18, 2015 at 9:52 AM, Victor Rodriguez
wrote:
> On Tue, Aug 18, 2015 at 8:25 AM, Kenneth Adam Miller
> wrote:
> > Ok- so I know that C is the defacto standard for kernel development. What
> > I'm not saying is that we
rnel is written in
C, but I sure would like my kernel module to be safer. If I can get it I
don't care what language it's in-it just has to work and *be secure*.
On Tue, Aug 18, 2015 at 9:40 AM, Robert P. J. Day
wrote:
> On Tue, 18 Aug 2015, Kenneth Adam Miller wrote:
>
> > Ok
Ok- so I know that C is the defacto standard for kernel development. What
I'm not saying is that we should all move away from it or that it should be
adopted internally. What I am saying is related to security concerns in
developing a kernel driver. What may come of it may generally allow for
bette
Well, if you really only want to find bugs in kernel code (specifically
linux drivers) there was a recent white paper that came out that used
Dynamo Rio to instrument and analyze the kernel. You can (I think) trigger
simulated events to the kernel and compose a sort of fuzzing environment
against a
So, I have a particular use case that has a lot to do with security.
Basically, we have a intended secure kernel version with grsecurity and
other patches on it, and we have a specific application that has to do data
filtering as an inline reference monitor.
The problem is, there is throughput an
Feb 20, 2015 at 03:26:40PM -0500, Kenneth Adam Miller wrote:
> > Thanks for your expedient answer!
> >
> > So, I was discussing an alternative to mocking; function hooking. But in
> a
> > benign way. Is there any way to, at runtime replace the functionality of
> code
&g
KH wrote:
> On Fri, Feb 20, 2015 at 02:51:25PM -0500, Kenneth Adam Miller wrote:
> > So, in userland development, the idea of mocking is used to isolate
> context
> > management and machine configuration into a single class or set of
> functions
> > that can be reused,
So, in userland development, the idea of mocking is used to isolate context
management and machine configuration into a single class or set of
functions that can be reused, and also facilitate testing much easier.
Google mock is a great example.
Say I develop a kernel module, and I want that modul
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