<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux.git/include/linux, branch v4.4.198</title>
<subtitle>Clone of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git</subtitle>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/'/>
<entry>
<title>cfg80211: Use const more consistently in for_each_element macros</title>
<updated>2019-10-17T20:40:57+00:00</updated>
<author>
<name>Jouni Malinen</name>
<email>j@w1.fi</email>
</author>
<published>2019-02-11T14:29:04+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=a698649b8e32f80ab1e863f9133ae00f8848544b'/>
<id>a698649b8e32f80ab1e863f9133ae00f8848544b</id>
<content type='text'>
commit 7388afe09143210f555bdd6c75035e9acc1fab96 upstream.

Enforce the first argument to be a correct type of a pointer to struct
element and avoid unnecessary typecasts from const to non-const pointers
(the change in validate_ie_attr() is needed to make this part work). In
addition, avoid signed/unsigned comparison within for_each_element() and
mark struct element packed just in case.

Signed-off-by: Jouni Malinen &lt;j@w1.fi&gt;
Signed-off-by: Johannes Berg &lt;johannes.berg@intel.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 7388afe09143210f555bdd6c75035e9acc1fab96 upstream.

Enforce the first argument to be a correct type of a pointer to struct
element and avoid unnecessary typecasts from const to non-const pointers
(the change in validate_ie_attr() is needed to make this part work). In
addition, avoid signed/unsigned comparison within for_each_element() and
mark struct element packed just in case.

Signed-off-by: Jouni Malinen &lt;j@w1.fi&gt;
Signed-off-by: Johannes Berg &lt;johannes.berg@intel.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>cfg80211: add and use strongly typed element iteration macros</title>
<updated>2019-10-17T20:40:57+00:00</updated>
<author>
<name>Johannes Berg</name>
<email>johannes.berg@intel.com</email>
</author>
<published>2019-02-07T20:44:41+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=933f4f10c9286ce577db1454abb6b50c124823f9'/>
<id>933f4f10c9286ce577db1454abb6b50c124823f9</id>
<content type='text'>
commit 0f3b07f027f87a38ebe5c436490095df762819be upstream.

Rather than always iterating elements from frames with pure
u8 pointers, add a type "struct element" that encapsulates
the id/datalen/data format of them.

Then, add the element iteration macros
 * for_each_element
 * for_each_element_id
 * for_each_element_extid

which take, as their first 'argument', such a structure and
iterate through a given u8 array interpreting it as elements.

While at it and since we'll need it, also add
 * for_each_subelement
 * for_each_subelement_id
 * for_each_subelement_extid

which instead of taking data/length just take an outer element
and use its data/datalen.

Also add for_each_element_completed() to determine if any of
the loops above completed, i.e. it was able to parse all of
the elements successfully and no data remained.

Use for_each_element_id() in cfg80211_find_ie_match() as the
first user of this.

Signed-off-by: Johannes Berg &lt;johannes.berg@intel.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 0f3b07f027f87a38ebe5c436490095df762819be upstream.

Rather than always iterating elements from frames with pure
u8 pointers, add a type "struct element" that encapsulates
the id/datalen/data format of them.

Then, add the element iteration macros
 * for_each_element
 * for_each_element_id
 * for_each_element_extid

which take, as their first 'argument', such a structure and
iterate through a given u8 array interpreting it as elements.

While at it and since we'll need it, also add
 * for_each_subelement
 * for_each_subelement_id
 * for_each_subelement_extid

which instead of taking data/length just take an outer element
and use its data/datalen.

Also add for_each_element_completed() to determine if any of
the loops above completed, i.e. it was able to parse all of
the elements successfully and no data remained.

Use for_each_element_id() in cfg80211_find_ie_match() as the
first user of this.

Signed-off-by: Johannes Berg &lt;johannes.berg@intel.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>quota: fix wrong condition in is_quota_modification()</title>
<updated>2019-10-05T10:27:55+00:00</updated>
<author>
<name>Chao Yu</name>
<email>yuchao0@huawei.com</email>
</author>
<published>2019-09-11T09:36:50+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=70a2b17f151e28ce659782ae9751b54ca9b6563b'/>
<id>70a2b17f151e28ce659782ae9751b54ca9b6563b</id>
<content type='text'>
commit 6565c182094f69e4ffdece337d395eb7ec760efc upstream.

Quoted from
commit 3da40c7b0898 ("ext4: only call ext4_truncate when size &lt;= isize")

" At LSF we decided that if we truncate up from isize we shouldn't trim
  fallocated blocks that were fallocated with KEEP_SIZE and are past the
 new i_size.  This patch fixes ext4 to do this. "

And generic/092 of fstest have covered this case for long time, however
is_quota_modification() didn't adjust based on that rule, so that in
below condition, we will lose to quota block change:
- fallocate blocks beyond EOF
- remount
- truncate(file_path, file_size)

Fix it.

Link: https://lore.kernel.org/r/20190911093650.35329-1-yuchao0@huawei.com
Fixes: 3da40c7b0898 ("ext4: only call ext4_truncate when size &lt;= isize")
CC: stable@vger.kernel.org
Signed-off-by: Chao Yu &lt;yuchao0@huawei.com&gt;
Signed-off-by: Jan Kara &lt;jack@suse.cz&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 6565c182094f69e4ffdece337d395eb7ec760efc upstream.

Quoted from
commit 3da40c7b0898 ("ext4: only call ext4_truncate when size &lt;= isize")

" At LSF we decided that if we truncate up from isize we shouldn't trim
  fallocated blocks that were fallocated with KEEP_SIZE and are past the
 new i_size.  This patch fixes ext4 to do this. "

And generic/092 of fstest have covered this case for long time, however
is_quota_modification() didn't adjust based on that rule, so that in
below condition, we will lose to quota block change:
- fallocate blocks beyond EOF
- remount
- truncate(file_path, file_size)

Fix it.

Link: https://lore.kernel.org/r/20190911093650.35329-1-yuchao0@huawei.com
Fixes: 3da40c7b0898 ("ext4: only call ext4_truncate when size &lt;= isize")
CC: stable@vger.kernel.org
Signed-off-by: Chao Yu &lt;yuchao0@huawei.com&gt;
Signed-off-by: Jan Kara &lt;jack@suse.cz&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>kprobes: Prohibit probing on BUG() and WARN() address</title>
<updated>2019-10-05T10:27:50+00:00</updated>
<author>
<name>Masami Hiramatsu</name>
<email>mhiramat@kernel.org</email>
</author>
<published>2019-09-03T11:08:21+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=c0505afc8a8e0ed7323c94caec9c21cac3358634'/>
<id>c0505afc8a8e0ed7323c94caec9c21cac3358634</id>
<content type='text'>
[ Upstream commit e336b4027775cb458dc713745e526fa1a1996b2a ]

Since BUG() and WARN() may use a trap (e.g. UD2 on x86) to
get the address where the BUG() has occurred, kprobes can not
do single-step out-of-line that instruction. So prohibit
probing on such address.

Without this fix, if someone put a kprobe on WARN(), the
kernel will crash with invalid opcode error instead of
outputing warning message, because kernel can not find
correct bug address.

Signed-off-by: Masami Hiramatsu &lt;mhiramat@kernel.org&gt;
Acked-by: Steven Rostedt (VMware) &lt;rostedt@goodmis.org&gt;
Acked-by: Naveen N. Rao &lt;naveen.n.rao@linux.vnet.ibm.com&gt;
Cc: Anil S Keshavamurthy &lt;anil.s.keshavamurthy@intel.com&gt;
Cc: David S . Miller &lt;davem@davemloft.net&gt;
Cc: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Cc: Naveen N . Rao &lt;naveen.n.rao@linux.ibm.com&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Steven Rostedt &lt;rostedt@goodmis.org&gt;
Cc: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Link: https://lkml.kernel.org/r/156750890133.19112.3393666300746167111.stgit@devnote2
Signed-off-by: Ingo Molnar &lt;mingo@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 e336b4027775cb458dc713745e526fa1a1996b2a ]

Since BUG() and WARN() may use a trap (e.g. UD2 on x86) to
get the address where the BUG() has occurred, kprobes can not
do single-step out-of-line that instruction. So prohibit
probing on such address.

Without this fix, if someone put a kprobe on WARN(), the
kernel will crash with invalid opcode error instead of
outputing warning message, because kernel can not find
correct bug address.

Signed-off-by: Masami Hiramatsu &lt;mhiramat@kernel.org&gt;
Acked-by: Steven Rostedt (VMware) &lt;rostedt@goodmis.org&gt;
Acked-by: Naveen N. Rao &lt;naveen.n.rao@linux.vnet.ibm.com&gt;
Cc: Anil S Keshavamurthy &lt;anil.s.keshavamurthy@intel.com&gt;
Cc: David S . Miller &lt;davem@davemloft.net&gt;
Cc: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Cc: Naveen N . Rao &lt;naveen.n.rao@linux.ibm.com&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Steven Rostedt &lt;rostedt@goodmis.org&gt;
Cc: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Link: https://lkml.kernel.org/r/156750890133.19112.3393666300746167111.stgit@devnote2
Signed-off-by: Ingo Molnar &lt;mingo@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>libceph: allow ceph_buffer_put() to receive a NULL ceph_buffer</title>
<updated>2019-09-10T09:29:49+00:00</updated>
<author>
<name>Luis Henriques</name>
<email>lhenriques@suse.com</email>
</author>
<published>2019-07-19T14:32:19+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=c3083eff1b1b3bdae7389ff0e2fb7ae9423561e4'/>
<id>c3083eff1b1b3bdae7389ff0e2fb7ae9423561e4</id>
<content type='text'>
[ Upstream commit 5c498950f730aa17c5f8a2cdcb903524e4002ed2 ]

Signed-off-by: Luis Henriques &lt;lhenriques@suse.com&gt;
Reviewed-by: Jeff Layton &lt;jlayton@kernel.org&gt;
Signed-off-by: Ilya Dryomov &lt;idryomov@gmail.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 5c498950f730aa17c5f8a2cdcb903524e4002ed2 ]

Signed-off-by: Luis Henriques &lt;lhenriques@suse.com&gt;
Reviewed-by: Jeff Layton &lt;jlayton@kernel.org&gt;
Signed-off-by: Ilya Dryomov &lt;idryomov@gmail.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>gpio: Fix build error of function redefinition</title>
<updated>2019-09-10T09:29:46+00:00</updated>
<author>
<name>YueHaibing</name>
<email>yuehaibing@huawei.com</email>
</author>
<published>2019-07-31T12:38:14+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=f46a46a9de0f1e005f64ade70336f9505a067a6e'/>
<id>f46a46a9de0f1e005f64ade70336f9505a067a6e</id>
<content type='text'>
[ Upstream commit 68e03b85474a51ec1921b4d13204782594ef7223 ]

when do randbuilding, I got this error:

In file included from drivers/hwmon/pmbus/ucd9000.c:19:0:
./include/linux/gpio/driver.h:576:1: error: redefinition of gpiochip_add_pin_range
 gpiochip_add_pin_range(struct gpio_chip *chip, const char *pinctl_name,
 ^~~~~~~~~~~~~~~~~~~~~~
In file included from drivers/hwmon/pmbus/ucd9000.c:18:0:
./include/linux/gpio.h:245:1: note: previous definition of gpiochip_add_pin_range was here
 gpiochip_add_pin_range(struct gpio_chip *chip, const char *pinctl_name,
 ^~~~~~~~~~~~~~~~~~~~~~

Reported-by: Hulk Robot &lt;hulkci@huawei.com&gt;
Fixes: 964cb341882f ("gpio: move pincontrol calls to &lt;linux/gpio/driver.h&gt;")
Signed-off-by: YueHaibing &lt;yuehaibing@huawei.com&gt;
Link: https://lore.kernel.org/r/20190731123814.46624-1-yuehaibing@huawei.com
Signed-off-by: Linus Walleij &lt;linus.walleij@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 68e03b85474a51ec1921b4d13204782594ef7223 ]

when do randbuilding, I got this error:

In file included from drivers/hwmon/pmbus/ucd9000.c:19:0:
./include/linux/gpio/driver.h:576:1: error: redefinition of gpiochip_add_pin_range
 gpiochip_add_pin_range(struct gpio_chip *chip, const char *pinctl_name,
 ^~~~~~~~~~~~~~~~~~~~~~
In file included from drivers/hwmon/pmbus/ucd9000.c:18:0:
./include/linux/gpio.h:245:1: note: previous definition of gpiochip_add_pin_range was here
 gpiochip_add_pin_range(struct gpio_chip *chip, const char *pinctl_name,
 ^~~~~~~~~~~~~~~~~~~~~~

Reported-by: Hulk Robot &lt;hulkci@huawei.com&gt;
Fixes: 964cb341882f ("gpio: move pincontrol calls to &lt;linux/gpio/driver.h&gt;")
Signed-off-by: YueHaibing &lt;yuehaibing@huawei.com&gt;
Link: https://lore.kernel.org/r/20190731123814.46624-1-yuehaibing@huawei.com
Signed-off-by: Linus Walleij &lt;linus.walleij@linaro.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>inet: switch IP ID generator to siphash</title>
<updated>2019-09-06T08:18:13+00:00</updated>
<author>
<name>Eric Dumazet</name>
<email>edumazet@google.com</email>
</author>
<published>2019-08-27T23:11:06+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=66f8c5ff8ed3d99dd21d8f24aac89410de7a4a05'/>
<id>66f8c5ff8ed3d99dd21d8f24aac89410de7a4a05</id>
<content type='text'>
commit df453700e8d81b1bdafdf684365ee2b9431fb702 upstream.

According to Amit Klein and Benny Pinkas, IP ID generation is too weak
and might be used by attackers.

Even with recent net_hash_mix() fix (netns: provide pure entropy for net_hash_mix())
having 64bit key and Jenkins hash is risky.

It is time to switch to siphash and its 128bit keys.

Signed-off-by: Eric Dumazet &lt;edumazet@google.com&gt;
Reported-by: Amit Klein &lt;aksecurity@gmail.com&gt;
Reported-by: Benny Pinkas &lt;benny@pinkas.net&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
[bwh: Backported to 4.4: adjust context]
Signed-off-by: Ben Hutchings &lt;ben.hutchings@codethink.co.uk&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit df453700e8d81b1bdafdf684365ee2b9431fb702 upstream.

According to Amit Klein and Benny Pinkas, IP ID generation is too weak
and might be used by attackers.

Even with recent net_hash_mix() fix (netns: provide pure entropy for net_hash_mix())
having 64bit key and Jenkins hash is risky.

It is time to switch to siphash and its 128bit keys.

Signed-off-by: Eric Dumazet &lt;edumazet@google.com&gt;
Reported-by: Amit Klein &lt;aksecurity@gmail.com&gt;
Reported-by: Benny Pinkas &lt;benny@pinkas.net&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
[bwh: Backported to 4.4: adjust context]
Signed-off-by: Ben Hutchings &lt;ben.hutchings@codethink.co.uk&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>siphash: implement HalfSipHash1-3 for hash tables</title>
<updated>2019-09-06T08:18:13+00:00</updated>
<author>
<name>Jason A. Donenfeld</name>
<email>Jason@zx2c4.com</email>
</author>
<published>2019-08-27T23:11:00+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=71b951c85b3b36480260a31419126b81f27db733'/>
<id>71b951c85b3b36480260a31419126b81f27db733</id>
<content type='text'>
commit 1ae2324f732c9c4e2fa4ebd885fa1001b70d52e1 upstream.

HalfSipHash, or hsiphash, is a shortened version of SipHash, which
generates 32-bit outputs using a weaker 64-bit key. It has *much* lower
security margins, and shouldn't be used for anything too sensitive, but
it could be used as a hashtable key function replacement, if the output
is never exposed, and if the security requirement is not too high.

The goal is to make this something that performance-critical jhash users
would be willing to use.

On 64-bit machines, HalfSipHash1-3 is slower than SipHash1-3, so we alias
SipHash1-3 to HalfSipHash1-3 on those systems.

64-bit x86_64:
[    0.509409] test_siphash:     SipHash2-4 cycles: 4049181
[    0.510650] test_siphash:     SipHash1-3 cycles: 2512884
[    0.512205] test_siphash: HalfSipHash1-3 cycles: 3429920
[    0.512904] test_siphash:    JenkinsHash cycles:  978267
So, we map hsiphash() -&gt; SipHash1-3

32-bit x86:
[    0.509868] test_siphash:     SipHash2-4 cycles: 14812892
[    0.513601] test_siphash:     SipHash1-3 cycles:  9510710
[    0.515263] test_siphash: HalfSipHash1-3 cycles:  3856157
[    0.515952] test_siphash:    JenkinsHash cycles:  1148567
So, we map hsiphash() -&gt; HalfSipHash1-3

hsiphash() is roughly 3 times slower than jhash(), but comes with a
considerable security improvement.

Signed-off-by: Jason A. Donenfeld &lt;Jason@zx2c4.com&gt;
Reviewed-by: Jean-Philippe Aumasson &lt;jeanphilippe.aumasson@gmail.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
[bwh: Backported to 4.4 to avoid regression for WireGuard with only half
 the siphash API present]
Signed-off-by: Ben Hutchings &lt;ben.hutchings@codethink.co.uk&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 1ae2324f732c9c4e2fa4ebd885fa1001b70d52e1 upstream.

HalfSipHash, or hsiphash, is a shortened version of SipHash, which
generates 32-bit outputs using a weaker 64-bit key. It has *much* lower
security margins, and shouldn't be used for anything too sensitive, but
it could be used as a hashtable key function replacement, if the output
is never exposed, and if the security requirement is not too high.

The goal is to make this something that performance-critical jhash users
would be willing to use.

On 64-bit machines, HalfSipHash1-3 is slower than SipHash1-3, so we alias
SipHash1-3 to HalfSipHash1-3 on those systems.

64-bit x86_64:
[    0.509409] test_siphash:     SipHash2-4 cycles: 4049181
[    0.510650] test_siphash:     SipHash1-3 cycles: 2512884
[    0.512205] test_siphash: HalfSipHash1-3 cycles: 3429920
[    0.512904] test_siphash:    JenkinsHash cycles:  978267
So, we map hsiphash() -&gt; SipHash1-3

32-bit x86:
[    0.509868] test_siphash:     SipHash2-4 cycles: 14812892
[    0.513601] test_siphash:     SipHash1-3 cycles:  9510710
[    0.515263] test_siphash: HalfSipHash1-3 cycles:  3856157
[    0.515952] test_siphash:    JenkinsHash cycles:  1148567
So, we map hsiphash() -&gt; HalfSipHash1-3

hsiphash() is roughly 3 times slower than jhash(), but comes with a
considerable security improvement.

Signed-off-by: Jason A. Donenfeld &lt;Jason@zx2c4.com&gt;
Reviewed-by: Jean-Philippe Aumasson &lt;jeanphilippe.aumasson@gmail.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
[bwh: Backported to 4.4 to avoid regression for WireGuard with only half
 the siphash API present]
Signed-off-by: Ben Hutchings &lt;ben.hutchings@codethink.co.uk&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>siphash: add cryptographically secure PRF</title>
<updated>2019-09-06T08:18:12+00:00</updated>
<author>
<name>Jason A. Donenfeld</name>
<email>Jason@zx2c4.com</email>
</author>
<published>2019-08-27T23:10:54+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=994fcca7f1c93f4e78008d5806c68067d3b75487'/>
<id>994fcca7f1c93f4e78008d5806c68067d3b75487</id>
<content type='text'>
commit 2c956a60778cbb6a27e0c7a8a52a91378c90e1d1 upstream.

SipHash is a 64-bit keyed hash function that is actually a
cryptographically secure PRF, like HMAC. Except SipHash is super fast,
and is meant to be used as a hashtable keyed lookup function, or as a
general PRF for short input use cases, such as sequence numbers or RNG
chaining.

For the first usage:

There are a variety of attacks known as "hashtable poisoning" in which an
attacker forms some data such that the hash of that data will be the
same, and then preceeds to fill up all entries of a hashbucket. This is
a realistic and well-known denial-of-service vector. Currently
hashtables use jhash, which is fast but not secure, and some kind of
rotating key scheme (or none at all, which isn't good). SipHash is meant
as a replacement for jhash in these cases.

There are a modicum of places in the kernel that are vulnerable to
hashtable poisoning attacks, either via userspace vectors or network
vectors, and there's not a reliable mechanism inside the kernel at the
moment to fix it. The first step toward fixing these issues is actually
getting a secure primitive into the kernel for developers to use. Then
we can, bit by bit, port things over to it as deemed appropriate.

While SipHash is extremely fast for a cryptographically secure function,
it is likely a bit slower than the insecure jhash, and so replacements
will be evaluated on a case-by-case basis based on whether or not the
difference in speed is negligible and whether or not the current jhash usage
poses a real security risk.

For the second usage:

A few places in the kernel are using MD5 or SHA1 for creating secure
sequence numbers, syn cookies, port numbers, or fast random numbers.
SipHash is a faster and more fitting, and more secure replacement for MD5
in those situations. Replacing MD5 and SHA1 with SipHash for these uses is
obvious and straight-forward, and so is submitted along with this patch
series. There shouldn't be much of a debate over its efficacy.

Dozens of languages are already using this internally for their hash
tables and PRFs. Some of the BSDs already use this in their kernels.
SipHash is a widely known high-speed solution to a widely known set of
problems, and it's time we catch-up.

Signed-off-by: Jason A. Donenfeld &lt;Jason@zx2c4.com&gt;
Reviewed-by: Jean-Philippe Aumasson &lt;jeanphilippe.aumasson@gmail.com&gt;
Cc: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Cc: Eric Biggers &lt;ebiggers3@gmail.com&gt;
Cc: David Laight &lt;David.Laight@aculab.com&gt;
Cc: Eric Dumazet &lt;eric.dumazet@gmail.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
[bwh: Backported to 4.4 as dependency of commits df453700e8d8 "inet: switch
 IP ID generator to siphash" and 3c79107631db "netfilter: ctnetlink: don't
 use conntrack/expect object addresses as id":
 - Adjust context]
Signed-off-by: Ben Hutchings &lt;ben.hutchings@codethink.co.uk&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 2c956a60778cbb6a27e0c7a8a52a91378c90e1d1 upstream.

SipHash is a 64-bit keyed hash function that is actually a
cryptographically secure PRF, like HMAC. Except SipHash is super fast,
and is meant to be used as a hashtable keyed lookup function, or as a
general PRF for short input use cases, such as sequence numbers or RNG
chaining.

For the first usage:

There are a variety of attacks known as "hashtable poisoning" in which an
attacker forms some data such that the hash of that data will be the
same, and then preceeds to fill up all entries of a hashbucket. This is
a realistic and well-known denial-of-service vector. Currently
hashtables use jhash, which is fast but not secure, and some kind of
rotating key scheme (or none at all, which isn't good). SipHash is meant
as a replacement for jhash in these cases.

There are a modicum of places in the kernel that are vulnerable to
hashtable poisoning attacks, either via userspace vectors or network
vectors, and there's not a reliable mechanism inside the kernel at the
moment to fix it. The first step toward fixing these issues is actually
getting a secure primitive into the kernel for developers to use. Then
we can, bit by bit, port things over to it as deemed appropriate.

While SipHash is extremely fast for a cryptographically secure function,
it is likely a bit slower than the insecure jhash, and so replacements
will be evaluated on a case-by-case basis based on whether or not the
difference in speed is negligible and whether or not the current jhash usage
poses a real security risk.

For the second usage:

A few places in the kernel are using MD5 or SHA1 for creating secure
sequence numbers, syn cookies, port numbers, or fast random numbers.
SipHash is a faster and more fitting, and more secure replacement for MD5
in those situations. Replacing MD5 and SHA1 with SipHash for these uses is
obvious and straight-forward, and so is submitted along with this patch
series. There shouldn't be much of a debate over its efficacy.

Dozens of languages are already using this internally for their hash
tables and PRFs. Some of the BSDs already use this in their kernels.
SipHash is a widely known high-speed solution to a widely known set of
problems, and it's time we catch-up.

Signed-off-by: Jason A. Donenfeld &lt;Jason@zx2c4.com&gt;
Reviewed-by: Jean-Philippe Aumasson &lt;jeanphilippe.aumasson@gmail.com&gt;
Cc: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Cc: Eric Biggers &lt;ebiggers3@gmail.com&gt;
Cc: David Laight &lt;David.Laight@aculab.com&gt;
Cc: Eric Dumazet &lt;eric.dumazet@gmail.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
[bwh: Backported to 4.4 as dependency of commits df453700e8d8 "inet: switch
 IP ID generator to siphash" and 3c79107631db "netfilter: ctnetlink: don't
 use conntrack/expect object addresses as id":
 - Adjust context]
Signed-off-by: Ben Hutchings &lt;ben.hutchings@codethink.co.uk&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>include/linux/module.h: copy __init/__exit attrs to init/cleanup_module</title>
<updated>2019-08-25T08:53:03+00:00</updated>
<author>
<name>Miguel Ojeda</name>
<email>miguel.ojeda.sandonis@gmail.com</email>
</author>
<published>2019-01-19T19:59:34+00:00</published>
<link rel='alternate' type='text/html' href='https://git.exis.tech/linux.git/commit/?id=170051d60cf08f9ae2cf296fb8410afdf56a911f'/>
<id>170051d60cf08f9ae2cf296fb8410afdf56a911f</id>
<content type='text'>
[ Upstream commit a6e60d84989fa0e91db7f236eda40453b0e44afa ]

The upcoming GCC 9 release extends the -Wmissing-attributes warnings
(enabled by -Wall) to C and aliases: it warns when particular function
attributes are missing in the aliases but not in their target.

In particular, it triggers for all the init/cleanup_module
aliases in the kernel (defined by the module_init/exit macros),
ending up being very noisy.

These aliases point to the __init/__exit functions of a module,
which are defined as __cold (among other attributes). However,
the aliases themselves do not have the __cold attribute.

Since the compiler behaves differently when compiling a __cold
function as well as when compiling paths leading to calls
to __cold functions, the warning is trying to point out
the possibly-forgotten attribute in the alias.

In order to keep the warning enabled, we decided to silence
this case. Ideally, we would mark the aliases directly
as __init/__exit. However, there are currently around 132 modules
in the kernel which are missing __init/__exit in their init/cleanup
functions (either because they are missing, or for other reasons,
e.g. the functions being called from somewhere else); and
a section mismatch is a hard error.

A conservative alternative was to mark the aliases as __cold only.
However, since we would like to eventually enforce __init/__exit
to be always marked,  we chose to use the new __copy function
attribute (introduced by GCC 9 as well to deal with this).
With it, we copy the attributes used by the target functions
into the aliases. This way, functions that were not marked
as __init/__exit won't have their aliases marked either,
and therefore there won't be a section mismatch.

Note that the warning would go away marking either the extern
declaration, the definition, or both. However, we only mark
the definition of the alias, since we do not want callers
(which only see the declaration) to be compiled as if the function
was __cold (and therefore the paths leading to those calls
would be assumed to be unlikely).

Link: https://lore.kernel.org/lkml/20190123173707.GA16603@gmail.com/
Link: https://lore.kernel.org/lkml/20190206175627.GA20399@gmail.com/
Suggested-by: Martin Sebor &lt;msebor@gcc.gnu.org&gt;
Acked-by: Jessica Yu &lt;jeyu@kernel.org&gt;
Signed-off-by: Miguel Ojeda &lt;miguel.ojeda.sandonis@gmail.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 a6e60d84989fa0e91db7f236eda40453b0e44afa ]

The upcoming GCC 9 release extends the -Wmissing-attributes warnings
(enabled by -Wall) to C and aliases: it warns when particular function
attributes are missing in the aliases but not in their target.

In particular, it triggers for all the init/cleanup_module
aliases in the kernel (defined by the module_init/exit macros),
ending up being very noisy.

These aliases point to the __init/__exit functions of a module,
which are defined as __cold (among other attributes). However,
the aliases themselves do not have the __cold attribute.

Since the compiler behaves differently when compiling a __cold
function as well as when compiling paths leading to calls
to __cold functions, the warning is trying to point out
the possibly-forgotten attribute in the alias.

In order to keep the warning enabled, we decided to silence
this case. Ideally, we would mark the aliases directly
as __init/__exit. However, there are currently around 132 modules
in the kernel which are missing __init/__exit in their init/cleanup
functions (either because they are missing, or for other reasons,
e.g. the functions being called from somewhere else); and
a section mismatch is a hard error.

A conservative alternative was to mark the aliases as __cold only.
However, since we would like to eventually enforce __init/__exit
to be always marked,  we chose to use the new __copy function
attribute (introduced by GCC 9 as well to deal with this).
With it, we copy the attributes used by the target functions
into the aliases. This way, functions that were not marked
as __init/__exit won't have their aliases marked either,
and therefore there won't be a section mismatch.

Note that the warning would go away marking either the extern
declaration, the definition, or both. However, we only mark
the definition of the alias, since we do not want callers
(which only see the declaration) to be compiled as if the function
was __cold (and therefore the paths leading to those calls
would be assumed to be unlikely).

Link: https://lore.kernel.org/lkml/20190123173707.GA16603@gmail.com/
Link: https://lore.kernel.org/lkml/20190206175627.GA20399@gmail.com/
Suggested-by: Martin Sebor &lt;msebor@gcc.gnu.org&gt;
Acked-by: Jessica Yu &lt;jeyu@kernel.org&gt;
Signed-off-by: Miguel Ojeda &lt;miguel.ojeda.sandonis@gmail.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
</feed>
