<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/include/linux, branch v5.4.48</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>sunrpc: clean up properly in gss_mech_unregister()</title>
<updated>2020-06-22T07:31:24+00:00</updated>
<author>
<name>NeilBrown</name>
<email>neilb@suse.de</email>
</author>
<published>2020-05-22T02:01:33+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=e5084eadf193b73e9e38b93f52fabad43d1fd268'/>
<id>e5084eadf193b73e9e38b93f52fabad43d1fd268</id>
<content type='text'>
commit 24c5efe41c29ee3e55bcf5a1c9f61ca8709622e8 upstream.

gss_mech_register() calls svcauth_gss_register_pseudoflavor() for each
flavour, but gss_mech_unregister() does not call auth_domain_put().
This is unbalanced and makes it impossible to reload the module.

Change svcauth_gss_register_pseudoflavor() to return the registered
auth_domain, and save it for later release.

Cc: stable@vger.kernel.org (v2.6.12+)
Link: https://bugzilla.kernel.org/show_bug.cgi?id=206651
Signed-off-by: NeilBrown &lt;neilb@suse.de&gt;
Signed-off-by: J. Bruce Fields &lt;bfields@redhat.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 24c5efe41c29ee3e55bcf5a1c9f61ca8709622e8 upstream.

gss_mech_register() calls svcauth_gss_register_pseudoflavor() for each
flavour, but gss_mech_unregister() does not call auth_domain_put().
This is unbalanced and makes it impossible to reload the module.

Change svcauth_gss_register_pseudoflavor() to return the registered
auth_domain, and save it for later release.

Cc: stable@vger.kernel.org (v2.6.12+)
Link: https://bugzilla.kernel.org/show_bug.cgi?id=206651
Signed-off-by: NeilBrown &lt;neilb@suse.de&gt;
Signed-off-by: J. Bruce Fields &lt;bfields@redhat.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>x86/amd_nb: Add AMD family 17h model 60h PCI IDs</title>
<updated>2020-06-22T07:31:17+00:00</updated>
<author>
<name>Alexander Monakov</name>
<email>amonakov@ispras.ru</email>
</author>
<published>2020-05-10T20:48:40+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=70ce85319d450a8e566467eab3395d318a69f832'/>
<id>70ce85319d450a8e566467eab3395d318a69f832</id>
<content type='text'>
[ Upstream commit a4e91825d7e1252f7cba005f1451e5464b23c15d ]

Add PCI IDs for AMD Renoir (4000-series Ryzen CPUs). This is necessary
to enable support for temperature sensors via the k10temp module.

Signed-off-by: Alexander Monakov &lt;amonakov@ispras.ru&gt;
Signed-off-by: Borislav Petkov &lt;bp@suse.de&gt;
Acked-by: Yazen Ghannam &lt;yazen.ghannam@amd.com&gt;
Acked-by: Guenter Roeck &lt;linux@roeck-us.net&gt;
Link: https://lkml.kernel.org/r/20200510204842.2603-2-amonakov@ispras.ru
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit a4e91825d7e1252f7cba005f1451e5464b23c15d ]

Add PCI IDs for AMD Renoir (4000-series Ryzen CPUs). This is necessary
to enable support for temperature sensors via the k10temp module.

Signed-off-by: Alexander Monakov &lt;amonakov@ispras.ru&gt;
Signed-off-by: Borislav Petkov &lt;bp@suse.de&gt;
Acked-by: Yazen Ghannam &lt;yazen.ghannam@amd.com&gt;
Acked-by: Guenter Roeck &lt;linux@roeck-us.net&gt;
Link: https://lkml.kernel.org/r/20200510204842.2603-2-amonakov@ispras.ru
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>serial: 8250_pci: Move Pericom IDs to pci_ids.h</title>
<updated>2020-06-22T07:31:17+00:00</updated>
<author>
<name>Kai-Heng Feng</name>
<email>kai.heng.feng@canonical.com</email>
</author>
<published>2020-05-08T06:53:40+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=44eec92cc4bff3cc9aa025706a625b940dd012c9'/>
<id>44eec92cc4bff3cc9aa025706a625b940dd012c9</id>
<content type='text'>
[ Upstream commit 62a7f3009a460001eb46984395280dd900bc4ef4 ]

Move the IDs to pci_ids.h so it can be used by next patch.

Link: https://lore.kernel.org/r/20200508065343.32751-1-kai.heng.feng@canonical.com
Signed-off-by: Kai-Heng Feng &lt;kai.heng.feng@canonical.com&gt;
Signed-off-by: Bjorn Helgaas &lt;bhelgaas@google.com&gt;
Acked-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Cc: stable@vger.kernel.org
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 62a7f3009a460001eb46984395280dd900bc4ef4 ]

Move the IDs to pci_ids.h so it can be used by next patch.

Link: https://lore.kernel.org/r/20200508065343.32751-1-kai.heng.feng@canonical.com
Signed-off-by: Kai-Heng Feng &lt;kai.heng.feng@canonical.com&gt;
Signed-off-by: Bjorn Helgaas &lt;bhelgaas@google.com&gt;
Acked-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Cc: stable@vger.kernel.org
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>PCI: Add Loongson vendor ID</title>
<updated>2020-06-22T07:31:17+00:00</updated>
<author>
<name>Tiezhu Yang</name>
<email>yangtiezhu@loongson.cn</email>
</author>
<published>2020-03-10T12:50:07+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=3c8938fb19edaa3542d9f3a22cd74e2d051a1ceb'/>
<id>3c8938fb19edaa3542d9f3a22cd74e2d051a1ceb</id>
<content type='text'>
[ Upstream commit 9acb9fe18d863aacc99948963f8d5d447dc311be ]

Add the Loongson vendor ID to pci_ids.h to be used by the controller
driver in the future.

The Loongson vendor ID can be found at the following link:
https://git.kernel.org/pub/scm/utils/pciutils/pciutils.git/tree/pci.ids

Signed-off-by: Tiezhu Yang &lt;yangtiezhu@loongson.cn&gt;
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 9acb9fe18d863aacc99948963f8d5d447dc311be ]

Add the Loongson vendor ID to pci_ids.h to be used by the controller
driver in the future.

The Loongson vendor ID can be found at the following link:
https://git.kernel.org/pub/scm/utils/pciutils/pciutils.git/tree/pci.ids

Signed-off-by: Tiezhu Yang &lt;yangtiezhu@loongson.cn&gt;
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>x86/amd_nb: Add Family 19h PCI IDs</title>
<updated>2020-06-22T07:31:16+00:00</updated>
<author>
<name>Yazen Ghannam</name>
<email>yazen.ghannam@amd.com</email>
</author>
<published>2020-01-10T01:56:49+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=9cfece5c0e2b774be5d613262b2df3789d2c5a3a'/>
<id>9cfece5c0e2b774be5d613262b2df3789d2c5a3a</id>
<content type='text'>
[ Upstream commit b3f79ae45904ae987a7c06a9e8d6084d7b73e67f ]

Add the new PCI Device 18h IDs for AMD Family 19h systems. Note that
Family 19h systems will not have a new PCI root device ID.

Signed-off-by: Yazen Ghannam &lt;yazen.ghannam@amd.com&gt;
Signed-off-by: Borislav Petkov &lt;bp@suse.de&gt;
Link: https://lkml.kernel.org/r/20200110015651.14887-4-Yazen.Ghannam@amd.com
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit b3f79ae45904ae987a7c06a9e8d6084d7b73e67f ]

Add the new PCI Device 18h IDs for AMD Family 19h systems. Note that
Family 19h systems will not have a new PCI root device ID.

Signed-off-by: Yazen Ghannam &lt;yazen.ghannam@amd.com&gt;
Signed-off-by: Borislav Petkov &lt;bp@suse.de&gt;
Link: https://lkml.kernel.org/r/20200110015651.14887-4-Yazen.Ghannam@amd.com
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>PCI: vmd: Add device id for VMD device 8086:9A0B</title>
<updated>2020-06-22T07:31:16+00:00</updated>
<author>
<name>Jon Derrick</name>
<email>jonathan.derrick@intel.com</email>
</author>
<published>2019-11-12T12:47:53+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=b35415c0949a111f956dcc645b23d5ab03b9a5dc'/>
<id>b35415c0949a111f956dcc645b23d5ab03b9a5dc</id>
<content type='text'>
[ Upstream commit ec11e5c213cc20cac5e8310728b06793448b9f6d ]

This patch adds support for this VMD device which supports the bus
restriction mode.

Signed-off-by: Jon Derrick &lt;jonathan.derrick@intel.com&gt;
Signed-off-by: Lorenzo Pieralisi &lt;lorenzo.pieralisi@arm.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit ec11e5c213cc20cac5e8310728b06793448b9f6d ]

This patch adds support for this VMD device which supports the bus
restriction mode.

Signed-off-by: Jon Derrick &lt;jonathan.derrick@intel.com&gt;
Signed-off-by: Lorenzo Pieralisi &lt;lorenzo.pieralisi@arm.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>mm: initialize deferred pages with interrupts enabled</title>
<updated>2020-06-22T07:31:14+00:00</updated>
<author>
<name>Pavel Tatashin</name>
<email>pasha.tatashin@soleen.com</email>
</author>
<published>2020-06-03T22:59:24+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=c388f173ed8a6b8c7b8f90389d17f58d77d28e4f'/>
<id>c388f173ed8a6b8c7b8f90389d17f58d77d28e4f</id>
<content type='text'>
commit 3d060856adfc59afb9d029c233141334cfaba418 upstream.

Initializing struct pages is a long task and keeping interrupts disabled
for the duration of this operation introduces a number of problems.

1. jiffies are not updated for long period of time, and thus incorrect time
   is reported. See proposed solution and discussion here:
   lkml/20200311123848.118638-1-shile.zhang@linux.alibaba.com
2. It prevents farther improving deferred page initialization by allowing
   intra-node multi-threading.

We are keeping interrupts disabled to solve a rather theoretical problem
that was never observed in real world (See 3a2d7fa8a3d5).

Let's keep interrupts enabled. In case we ever encounter a scenario where
an interrupt thread wants to allocate large amount of memory this early in
boot we can deal with that by growing zone (see deferred_grow_zone()) by
the needed amount before starting deferred_init_memmap() threads.

Before:
[    1.232459] node 0 initialised, 12058412 pages in 1ms

After:
[    1.632580] node 0 initialised, 12051227 pages in 436ms

Fixes: 3a2d7fa8a3d5 ("mm: disable interrupts while initializing deferred pages")
Reported-by: Shile Zhang &lt;shile.zhang@linux.alibaba.com&gt;
Signed-off-by: Pavel Tatashin &lt;pasha.tatashin@soleen.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Reviewed-by: Daniel Jordan &lt;daniel.m.jordan@oracle.com&gt;
Reviewed-by: David Hildenbrand &lt;david@redhat.com&gt;
Acked-by: Michal Hocko &lt;mhocko@suse.com&gt;
Acked-by: Vlastimil Babka &lt;vbabka@suse.cz&gt;
Cc: Dan Williams &lt;dan.j.williams@intel.com&gt;
Cc: James Morris &lt;jmorris@namei.org&gt;
Cc: Kirill Tkhai &lt;ktkhai@virtuozzo.com&gt;
Cc: Sasha Levin &lt;sashal@kernel.org&gt;
Cc: Yiqian Wei &lt;yiwei@redhat.com&gt;
Cc: &lt;stable@vger.kernel.org&gt;	[4.17+]
Link: http://lkml.kernel.org/r/20200403140952.17177-3-pasha.tatashin@soleen.com
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 3d060856adfc59afb9d029c233141334cfaba418 upstream.

Initializing struct pages is a long task and keeping interrupts disabled
for the duration of this operation introduces a number of problems.

1. jiffies are not updated for long period of time, and thus incorrect time
   is reported. See proposed solution and discussion here:
   lkml/20200311123848.118638-1-shile.zhang@linux.alibaba.com
2. It prevents farther improving deferred page initialization by allowing
   intra-node multi-threading.

We are keeping interrupts disabled to solve a rather theoretical problem
that was never observed in real world (See 3a2d7fa8a3d5).

Let's keep interrupts enabled. In case we ever encounter a scenario where
an interrupt thread wants to allocate large amount of memory this early in
boot we can deal with that by growing zone (see deferred_grow_zone()) by
the needed amount before starting deferred_init_memmap() threads.

Before:
[    1.232459] node 0 initialised, 12058412 pages in 1ms

After:
[    1.632580] node 0 initialised, 12051227 pages in 436ms

Fixes: 3a2d7fa8a3d5 ("mm: disable interrupts while initializing deferred pages")
Reported-by: Shile Zhang &lt;shile.zhang@linux.alibaba.com&gt;
Signed-off-by: Pavel Tatashin &lt;pasha.tatashin@soleen.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Reviewed-by: Daniel Jordan &lt;daniel.m.jordan@oracle.com&gt;
Reviewed-by: David Hildenbrand &lt;david@redhat.com&gt;
Acked-by: Michal Hocko &lt;mhocko@suse.com&gt;
Acked-by: Vlastimil Babka &lt;vbabka@suse.cz&gt;
Cc: Dan Williams &lt;dan.j.williams@intel.com&gt;
Cc: James Morris &lt;jmorris@namei.org&gt;
Cc: Kirill Tkhai &lt;ktkhai@virtuozzo.com&gt;
Cc: Sasha Levin &lt;sashal@kernel.org&gt;
Cc: Yiqian Wei &lt;yiwei@redhat.com&gt;
Cc: &lt;stable@vger.kernel.org&gt;	[4.17+]
Link: http://lkml.kernel.org/r/20200403140952.17177-3-pasha.tatashin@soleen.com
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>string.h: fix incompatibility between FORTIFY_SOURCE and KASAN</title>
<updated>2020-06-22T07:31:12+00:00</updated>
<author>
<name>Daniel Axtens</name>
<email>dja@axtens.net</email>
</author>
<published>2020-06-03T22:56:46+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=b008ae4cc74d3ab43074099746f6c32d353e01aa'/>
<id>b008ae4cc74d3ab43074099746f6c32d353e01aa</id>
<content type='text'>
[ Upstream commit 47227d27e2fcb01a9e8f5958d8997cf47a820afc ]

The memcmp KASAN self-test fails on a kernel with both KASAN and
FORTIFY_SOURCE.

When FORTIFY_SOURCE is on, a number of functions are replaced with
fortified versions, which attempt to check the sizes of the operands.
However, these functions often directly invoke __builtin_foo() once they
have performed the fortify check.  Using __builtins may bypass KASAN
checks if the compiler decides to inline it's own implementation as
sequence of instructions, rather than emit a function call that goes out
to a KASAN-instrumented implementation.

Why is only memcmp affected?
============================

Of the string and string-like functions that kasan_test tests, only memcmp
is replaced by an inline sequence of instructions in my testing on x86
with gcc version 9.2.1 20191008 (Ubuntu 9.2.1-9ubuntu2).

I believe this is due to compiler heuristics.  For example, if I annotate
kmalloc calls with the alloc_size annotation (and disable some fortify
compile-time checking!), the compiler will replace every memset except the
one in kmalloc_uaf_memset with inline instructions.  (I have some WIP
patches to add this annotation.)

Does this affect other functions in string.h?
=============================================

Yes. Anything that uses __builtin_* rather than __real_* could be
affected. This looks like:

 - strncpy
 - strcat
 - strlen
 - strlcpy maybe, under some circumstances?
 - strncat under some circumstances
 - memset
 - memcpy
 - memmove
 - memcmp (as noted)
 - memchr
 - strcpy

Whether a function call is emitted always depends on the compiler.  Most
bugs should get caught by FORTIFY_SOURCE, but the missed memcmp test shows
that this is not always the case.

Isn't FORTIFY_SOURCE disabled with KASAN?
========================================-

The string headers on all arches supporting KASAN disable fortify with
kasan, but only when address sanitisation is _also_ disabled.  For example
from x86:

 #if defined(CONFIG_KASAN) &amp;&amp; !defined(__SANITIZE_ADDRESS__)
 /*
  * For files that are not instrumented (e.g. mm/slub.c) we
  * should use not instrumented version of mem* functions.
  */
 #define memcpy(dst, src, len) __memcpy(dst, src, len)
 #define memmove(dst, src, len) __memmove(dst, src, len)
 #define memset(s, c, n) __memset(s, c, n)

 #ifndef __NO_FORTIFY
 #define __NO_FORTIFY /* FORTIFY_SOURCE uses __builtin_memcpy, etc. */
 #endif

 #endif

This comes from commit 6974f0c4555e ("include/linux/string.h: add the
option of fortified string.h functions"), and doesn't work when KASAN is
enabled and the file is supposed to be sanitised - as with test_kasan.c

I'm pretty sure this is not wrong, but not as expansive it should be:

 * we shouldn't use __builtin_memcpy etc in files where we don't have
   instrumentation - it could devolve into a function call to memcpy,
   which will be instrumented. Rather, we should use __memcpy which
   by convention is not instrumented.

 * we also shouldn't be using __builtin_memcpy when we have a KASAN
   instrumented file, because it could be replaced with inline asm
   that will not be instrumented.

What is correct behaviour?
==========================

Firstly, there is some overlap between fortification and KASAN: both
provide some level of _runtime_ checking. Only fortify provides
compile-time checking.

KASAN and fortify can pick up different things at runtime:

 - Some fortify functions, notably the string functions, could easily be
   modified to consider sub-object sizes (e.g. members within a struct),
   and I have some WIP patches to do this. KASAN cannot detect these
   because it cannot insert poision between members of a struct.

 - KASAN can detect many over-reads/over-writes when the sizes of both
   operands are unknown, which fortify cannot.

So there are a couple of options:

 1) Flip the test: disable fortify in santised files and enable it in
    unsanitised files. This at least stops us missing KASAN checking, but
    we lose the fortify checking.

 2) Make the fortify code always call out to real versions. Do this only
    for KASAN, for fear of losing the inlining opportunities we get from
    __builtin_*.

(We can't use kasan_check_{read,write}: because the fortify functions are
_extern inline_, you can't include _static_ inline functions without a
compiler warning. kasan_check_{read,write} are static inline so we can't
use them even when they would otherwise be suitable.)

Take approach 2 and call out to real versions when KASAN is enabled.

Use __underlying_foo to distinguish from __real_foo: __real_foo always
refers to the kernel's implementation of foo, __underlying_foo could be
either the kernel implementation or the __builtin_foo implementation.

This is sometimes enough to make the memcmp test succeed with
FORTIFY_SOURCE enabled. It is at least enough to get the function call
into the module. One more fix is needed to make it reliable: see the next
patch.

Fixes: 6974f0c4555e ("include/linux/string.h: add the option of fortified string.h functions")
Signed-off-by: Daniel Axtens &lt;dja@axtens.net&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Tested-by: David Gow &lt;davidgow@google.com&gt;
Reviewed-by: Dmitry Vyukov &lt;dvyukov@google.com&gt;
Cc: Daniel Micay &lt;danielmicay@gmail.com&gt;
Cc: Andrey Ryabinin &lt;aryabinin@virtuozzo.com&gt;
Cc: Alexander Potapenko &lt;glider@google.com&gt;
Link: http://lkml.kernel.org/r/20200423154503.5103-3-dja@axtens.net
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 47227d27e2fcb01a9e8f5958d8997cf47a820afc ]

The memcmp KASAN self-test fails on a kernel with both KASAN and
FORTIFY_SOURCE.

When FORTIFY_SOURCE is on, a number of functions are replaced with
fortified versions, which attempt to check the sizes of the operands.
However, these functions often directly invoke __builtin_foo() once they
have performed the fortify check.  Using __builtins may bypass KASAN
checks if the compiler decides to inline it's own implementation as
sequence of instructions, rather than emit a function call that goes out
to a KASAN-instrumented implementation.

Why is only memcmp affected?
============================

Of the string and string-like functions that kasan_test tests, only memcmp
is replaced by an inline sequence of instructions in my testing on x86
with gcc version 9.2.1 20191008 (Ubuntu 9.2.1-9ubuntu2).

I believe this is due to compiler heuristics.  For example, if I annotate
kmalloc calls with the alloc_size annotation (and disable some fortify
compile-time checking!), the compiler will replace every memset except the
one in kmalloc_uaf_memset with inline instructions.  (I have some WIP
patches to add this annotation.)

Does this affect other functions in string.h?
=============================================

Yes. Anything that uses __builtin_* rather than __real_* could be
affected. This looks like:

 - strncpy
 - strcat
 - strlen
 - strlcpy maybe, under some circumstances?
 - strncat under some circumstances
 - memset
 - memcpy
 - memmove
 - memcmp (as noted)
 - memchr
 - strcpy

Whether a function call is emitted always depends on the compiler.  Most
bugs should get caught by FORTIFY_SOURCE, but the missed memcmp test shows
that this is not always the case.

Isn't FORTIFY_SOURCE disabled with KASAN?
========================================-

The string headers on all arches supporting KASAN disable fortify with
kasan, but only when address sanitisation is _also_ disabled.  For example
from x86:

 #if defined(CONFIG_KASAN) &amp;&amp; !defined(__SANITIZE_ADDRESS__)
 /*
  * For files that are not instrumented (e.g. mm/slub.c) we
  * should use not instrumented version of mem* functions.
  */
 #define memcpy(dst, src, len) __memcpy(dst, src, len)
 #define memmove(dst, src, len) __memmove(dst, src, len)
 #define memset(s, c, n) __memset(s, c, n)

 #ifndef __NO_FORTIFY
 #define __NO_FORTIFY /* FORTIFY_SOURCE uses __builtin_memcpy, etc. */
 #endif

 #endif

This comes from commit 6974f0c4555e ("include/linux/string.h: add the
option of fortified string.h functions"), and doesn't work when KASAN is
enabled and the file is supposed to be sanitised - as with test_kasan.c

I'm pretty sure this is not wrong, but not as expansive it should be:

 * we shouldn't use __builtin_memcpy etc in files where we don't have
   instrumentation - it could devolve into a function call to memcpy,
   which will be instrumented. Rather, we should use __memcpy which
   by convention is not instrumented.

 * we also shouldn't be using __builtin_memcpy when we have a KASAN
   instrumented file, because it could be replaced with inline asm
   that will not be instrumented.

What is correct behaviour?
==========================

Firstly, there is some overlap between fortification and KASAN: both
provide some level of _runtime_ checking. Only fortify provides
compile-time checking.

KASAN and fortify can pick up different things at runtime:

 - Some fortify functions, notably the string functions, could easily be
   modified to consider sub-object sizes (e.g. members within a struct),
   and I have some WIP patches to do this. KASAN cannot detect these
   because it cannot insert poision between members of a struct.

 - KASAN can detect many over-reads/over-writes when the sizes of both
   operands are unknown, which fortify cannot.

So there are a couple of options:

 1) Flip the test: disable fortify in santised files and enable it in
    unsanitised files. This at least stops us missing KASAN checking, but
    we lose the fortify checking.

 2) Make the fortify code always call out to real versions. Do this only
    for KASAN, for fear of losing the inlining opportunities we get from
    __builtin_*.

(We can't use kasan_check_{read,write}: because the fortify functions are
_extern inline_, you can't include _static_ inline functions without a
compiler warning. kasan_check_{read,write} are static inline so we can't
use them even when they would otherwise be suitable.)

Take approach 2 and call out to real versions when KASAN is enabled.

Use __underlying_foo to distinguish from __real_foo: __real_foo always
refers to the kernel's implementation of foo, __underlying_foo could be
either the kernel implementation or the __builtin_foo implementation.

This is sometimes enough to make the memcmp test succeed with
FORTIFY_SOURCE enabled. It is at least enough to get the function call
into the module. One more fix is needed to make it reliable: see the next
patch.

Fixes: 6974f0c4555e ("include/linux/string.h: add the option of fortified string.h functions")
Signed-off-by: Daniel Axtens &lt;dja@axtens.net&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Tested-by: David Gow &lt;davidgow@google.com&gt;
Reviewed-by: Dmitry Vyukov &lt;dvyukov@google.com&gt;
Cc: Daniel Micay &lt;danielmicay@gmail.com&gt;
Cc: Andrey Ryabinin &lt;aryabinin@virtuozzo.com&gt;
Cc: Alexander Potapenko &lt;glider@google.com&gt;
Link: http://lkml.kernel.org/r/20200423154503.5103-3-dja@axtens.net
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>bpf: Fix running sk_skb program types with ktls</title>
<updated>2020-06-22T07:31:12+00:00</updated>
<author>
<name>John Fastabend</name>
<email>john.fastabend@gmail.com</email>
</author>
<published>2020-05-29T23:06:59+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=e7b1564a24e62b302ce9cb39765f0ac9814ffabd'/>
<id>e7b1564a24e62b302ce9cb39765f0ac9814ffabd</id>
<content type='text'>
[ Upstream commit e91de6afa81c10e9f855c5695eb9a53168d96b73 ]

KTLS uses a stream parser to collect TLS messages and send them to
the upper layer tls receive handler. This ensures the tls receiver
has a full TLS header to parse when it is run. However, when a
socket has BPF_SK_SKB_STREAM_VERDICT program attached before KTLS
is enabled we end up with two stream parsers running on the same
socket.

The result is both try to run on the same socket. First the KTLS
stream parser runs and calls read_sock() which will tcp_read_sock
which in turn calls tcp_rcv_skb(). This dequeues the skb from the
sk_receive_queue. When this is done KTLS code then data_ready()
callback which because we stacked KTLS on top of the bpf stream
verdict program has been replaced with sk_psock_start_strp(). This
will in turn kick the stream parser again and eventually do the
same thing KTLS did above calling into tcp_rcv_skb() and dequeuing
a skb from the sk_receive_queue.

At this point the data stream is broke. Part of the stream was
handled by the KTLS side some other bytes may have been handled
by the BPF side. Generally this results in either missing data
or more likely a "Bad Message" complaint from the kTLS receive
handler as the BPF program steals some bytes meant to be in a
TLS header and/or the TLS header length is no longer correct.

We've already broke the idealized model where we can stack ULPs
in any order with generic callbacks on the TX side to handle this.
So in this patch we do the same thing but for RX side. We add
a sk_psock_strp_enabled() helper so TLS can learn a BPF verdict
program is running and add a tls_sw_has_ctx_rx() helper so BPF
side can learn there is a TLS ULP on the socket.

Then on BPF side we omit calling our stream parser to avoid
breaking the data stream for the KTLS receiver. Then on the
KTLS side we call BPF_SK_SKB_STREAM_VERDICT once the KTLS
receiver is done with the packet but before it posts the
msg to userspace. This gives us symmetry between the TX and
RX halfs and IMO makes it usable again. On the TX side we
process packets in this order BPF -&gt; TLS -&gt; TCP and on
the receive side in the reverse order TCP -&gt; TLS -&gt; BPF.

Discovered while testing OpenSSL 3.0 Alpha2.0 release.

Fixes: d829e9c4112b5 ("tls: convert to generic sk_msg interface")
Signed-off-by: John Fastabend &lt;john.fastabend@gmail.com&gt;
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
Link: https://lore.kernel.org/bpf/159079361946.5745.605854335665044485.stgit@john-Precision-5820-Tower
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit e91de6afa81c10e9f855c5695eb9a53168d96b73 ]

KTLS uses a stream parser to collect TLS messages and send them to
the upper layer tls receive handler. This ensures the tls receiver
has a full TLS header to parse when it is run. However, when a
socket has BPF_SK_SKB_STREAM_VERDICT program attached before KTLS
is enabled we end up with two stream parsers running on the same
socket.

The result is both try to run on the same socket. First the KTLS
stream parser runs and calls read_sock() which will tcp_read_sock
which in turn calls tcp_rcv_skb(). This dequeues the skb from the
sk_receive_queue. When this is done KTLS code then data_ready()
callback which because we stacked KTLS on top of the bpf stream
verdict program has been replaced with sk_psock_start_strp(). This
will in turn kick the stream parser again and eventually do the
same thing KTLS did above calling into tcp_rcv_skb() and dequeuing
a skb from the sk_receive_queue.

At this point the data stream is broke. Part of the stream was
handled by the KTLS side some other bytes may have been handled
by the BPF side. Generally this results in either missing data
or more likely a "Bad Message" complaint from the kTLS receive
handler as the BPF program steals some bytes meant to be in a
TLS header and/or the TLS header length is no longer correct.

We've already broke the idealized model where we can stack ULPs
in any order with generic callbacks on the TX side to handle this.
So in this patch we do the same thing but for RX side. We add
a sk_psock_strp_enabled() helper so TLS can learn a BPF verdict
program is running and add a tls_sw_has_ctx_rx() helper so BPF
side can learn there is a TLS ULP on the socket.

Then on BPF side we omit calling our stream parser to avoid
breaking the data stream for the KTLS receiver. Then on the
KTLS side we call BPF_SK_SKB_STREAM_VERDICT once the KTLS
receiver is done with the packet but before it posts the
msg to userspace. This gives us symmetry between the TX and
RX halfs and IMO makes it usable again. On the TX side we
process packets in this order BPF -&gt; TLS -&gt; TCP and on
the receive side in the reverse order TCP -&gt; TLS -&gt; BPF.

Discovered while testing OpenSSL 3.0 Alpha2.0 release.

Fixes: d829e9c4112b5 ("tls: convert to generic sk_msg interface")
Signed-off-by: John Fastabend &lt;john.fastabend@gmail.com&gt;
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
Link: https://lore.kernel.org/bpf/159079361946.5745.605854335665044485.stgit@john-Precision-5820-Tower
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>kgdb: Fix spurious true from in_dbg_master()</title>
<updated>2020-06-22T07:31:03+00:00</updated>
<author>
<name>Daniel Thompson</name>
<email>daniel.thompson@linaro.org</email>
</author>
<published>2020-05-06T16:42:23+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=4f1a132115ef54eb4136ae24035ee62c9f41c201'/>
<id>4f1a132115ef54eb4136ae24035ee62c9f41c201</id>
<content type='text'>
[ Upstream commit 3fec4aecb311995189217e64d725cfe84a568de3 ]

Currently there is a small window where a badly timed migration could
cause in_dbg_master() to spuriously return true. Specifically if we
migrate to a new core after reading the processor id and the previous
core takes a breakpoint then we will evaluate true if we read
kgdb_active before we get the IPI to bring us to halt.

Fix this by checking irqs_disabled() first. Interrupts are always
disabled when we are executing the kgdb trap so this is an acceptable
prerequisite. This also allows us to replace raw_smp_processor_id()
with smp_processor_id() since the short circuit logic will prevent
warnings from PREEMPT_DEBUG.

Fixes: dcc7871128e9 ("kgdb: core changes to support kdb")
Suggested-by: Will Deacon &lt;will@kernel.org&gt;
Link: https://lore.kernel.org/r/20200506164223.2875760-1-daniel.thompson@linaro.org
Reviewed-by: Douglas Anderson &lt;dianders@chromium.org&gt;
Signed-off-by: Daniel Thompson &lt;daniel.thompson@linaro.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 3fec4aecb311995189217e64d725cfe84a568de3 ]

Currently there is a small window where a badly timed migration could
cause in_dbg_master() to spuriously return true. Specifically if we
migrate to a new core after reading the processor id and the previous
core takes a breakpoint then we will evaluate true if we read
kgdb_active before we get the IPI to bring us to halt.

Fix this by checking irqs_disabled() first. Interrupts are always
disabled when we are executing the kgdb trap so this is an acceptable
prerequisite. This also allows us to replace raw_smp_processor_id()
with smp_processor_id() since the short circuit logic will prevent
warnings from PREEMPT_DEBUG.

Fixes: dcc7871128e9 ("kgdb: core changes to support kdb")
Suggested-by: Will Deacon &lt;will@kernel.org&gt;
Link: https://lore.kernel.org/r/20200506164223.2875760-1-daniel.thompson@linaro.org
Reviewed-by: Douglas Anderson &lt;dianders@chromium.org&gt;
Signed-off-by: Daniel Thompson &lt;daniel.thompson@linaro.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
</feed>
