<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/include, branch v4.19.322</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>netns: add pre_exit method to struct pernet_operations</title>
<updated>2024-09-12T09:02:55+00:00</updated>
<author>
<name>Eric Dumazet</name>
<email>edumazet@google.com</email>
</author>
<published>2019-06-18T18:08:59+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=bc596c2026c7f52dc12a784403ccfc3b152844e6'/>
<id>bc596c2026c7f52dc12a784403ccfc3b152844e6</id>
<content type='text'>
commit d7d99872c144a2c2f5d9c9d83627fa833836cba5 upstream.

Current struct pernet_operations exit() handlers are highly
discouraged to call synchronize_rcu().

There are cases where we need them, and exit_batch() does
not help the common case where a single netns is dismantled.

This patch leverages the existing synchronize_rcu() call
in cleanup_net()

Calling optional -&gt;pre_exit() method before -&gt;exit() or
-&gt;exit_batch() allows to benefit from a single synchronize_rcu()
call.

Note that the synchronize_rcu() calls added in this patch
are only in error paths or slow paths.

Tested:

$ time for i in {1..1000}; do unshare -n /bin/false;done

real	0m2.612s
user	0m0.171s
sys	0m2.216s

Signed-off-by: Eric Dumazet &lt;edumazet@google.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&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 d7d99872c144a2c2f5d9c9d83627fa833836cba5 upstream.

Current struct pernet_operations exit() handlers are highly
discouraged to call synchronize_rcu().

There are cases where we need them, and exit_batch() does
not help the common case where a single netns is dismantled.

This patch leverages the existing synchronize_rcu() call
in cleanup_net()

Calling optional -&gt;pre_exit() method before -&gt;exit() or
-&gt;exit_batch() allows to benefit from a single synchronize_rcu()
call.

Note that the synchronize_rcu() calls added in this patch
are only in error paths or slow paths.

Tested:

$ time for i in {1..1000}; do unshare -n /bin/false;done

real	0m2.612s
user	0m0.171s
sys	0m2.216s

Signed-off-by: Eric Dumazet &lt;edumazet@google.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ring-buffer: Rename ring_buffer_read() to read_buffer_iter_advance()</title>
<updated>2024-09-12T09:02:55+00:00</updated>
<author>
<name>Steven Rostedt (VMware)</name>
<email>rostedt@goodmis.org</email>
</author>
<published>2020-03-17T21:32:25+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=ac8ffa21dde0c1edcd9dd98b5555a0aa4eea3b1f'/>
<id>ac8ffa21dde0c1edcd9dd98b5555a0aa4eea3b1f</id>
<content type='text'>
[ Upstream commit bc1a72afdc4a91844928831cac85731566e03bc6 ]

When the ring buffer was first created, the iterator followed the normal
producer/consumer operations where it had both a peek() operation, that just
returned the event at the current location, and a read(), that would return
the event at the current location and also increment the iterator such that
the next peek() or read() will return the next event.

The only use of the ring_buffer_read() is currently to move the iterator to
the next location and nothing now actually reads the event it returns.
Rename this function to its actual use case to ring_buffer_iter_advance(),
which also adds the "iter" part to the name, which is more meaningful. As
the timestamp returned by ring_buffer_read() was never used, there's no
reason that this new version should bother having returning it. It will also
become a void function.

Link: http://lkml.kernel.org/r/20200317213416.018928618@goodmis.org

Signed-off-by: Steven Rostedt (VMware) &lt;rostedt@goodmis.org&gt;
Stable-dep-of: 49aa8a1f4d68 ("tracing: Avoid possible softlockup in tracing_iter_reset()")
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 bc1a72afdc4a91844928831cac85731566e03bc6 ]

When the ring buffer was first created, the iterator followed the normal
producer/consumer operations where it had both a peek() operation, that just
returned the event at the current location, and a read(), that would return
the event at the current location and also increment the iterator such that
the next peek() or read() will return the next event.

The only use of the ring_buffer_read() is currently to move the iterator to
the next location and nothing now actually reads the event it returns.
Rename this function to its actual use case to ring_buffer_iter_advance(),
which also adds the "iter" part to the name, which is more meaningful. As
the timestamp returned by ring_buffer_read() was never used, there's no
reason that this new version should bother having returning it. It will also
become a void function.

Link: http://lkml.kernel.org/r/20200317213416.018928618@goodmis.org

Signed-off-by: Steven Rostedt (VMware) &lt;rostedt@goodmis.org&gt;
Stable-dep-of: 49aa8a1f4d68 ("tracing: Avoid possible softlockup in tracing_iter_reset()")
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>bridge: switchdev: Allow clearing FDB entry offload indication</title>
<updated>2024-09-12T09:02:52+00:00</updated>
<author>
<name>Ido Schimmel</name>
<email>idosch@mellanox.com</email>
</author>
<published>2018-10-17T08:53:29+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=76c1d0d1cbedf122ed90cb64a05c440eedd39664'/>
<id>76c1d0d1cbedf122ed90cb64a05c440eedd39664</id>
<content type='text'>
[ Upstream commit e9ba0fbc7dd23a74e77960c98c988f59a1ff75aa ]

Currently, an FDB entry only ceases being offloaded when it is deleted.
This changes with VxLAN encapsulation.

Devices capable of performing VxLAN encapsulation usually have only one
FDB table, unlike the software data path which has two - one in the
bridge driver and another in the VxLAN driver.

Therefore, bridge FDB entries pointing to a VxLAN device are only
offloaded if there is a corresponding entry in the VxLAN FDB.

Allow clearing the offload indication in case the corresponding entry
was deleted from the VxLAN FDB.

Signed-off-by: Ido Schimmel &lt;idosch@mellanox.com&gt;
Reviewed-by: Petr Machata &lt;petrm@mellanox.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Stable-dep-of: bee2ef946d31 ("net: bridge: br_fdb_external_learn_add(): always set EXT_LEARN")
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 e9ba0fbc7dd23a74e77960c98c988f59a1ff75aa ]

Currently, an FDB entry only ceases being offloaded when it is deleted.
This changes with VxLAN encapsulation.

Devices capable of performing VxLAN encapsulation usually have only one
FDB table, unlike the software data path which has two - one in the
bridge driver and another in the VxLAN driver.

Therefore, bridge FDB entries pointing to a VxLAN device are only
offloaded if there is a corresponding entry in the VxLAN FDB.

Allow clearing the offload indication in case the corresponding entry
was deleted from the VxLAN FDB.

Signed-off-by: Ido Schimmel &lt;idosch@mellanox.com&gt;
Reviewed-by: Petr Machata &lt;petrm@mellanox.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Stable-dep-of: bee2ef946d31 ("net: bridge: br_fdb_external_learn_add(): always set EXT_LEARN")
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: bridge: add support for sticky fdb entries</title>
<updated>2024-09-12T09:02:52+00:00</updated>
<author>
<name>Nikolay Aleksandrov</name>
<email>nikolay@cumulusnetworks.com</email>
</author>
<published>2018-09-11T06:39:53+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=c5a0142c4d33b5948879cd5ec0af50eb92109465'/>
<id>c5a0142c4d33b5948879cd5ec0af50eb92109465</id>
<content type='text'>
[ Upstream commit 435f2e7cc0b783615d7fbcf08f5f00d289f9caeb ]

Add support for entries which are "sticky", i.e. will not change their port
if they show up from a different one. A new ndm flag is introduced for that
purpose - NTF_STICKY. We allow to set it only to non-local entries.

Signed-off-by: Nikolay Aleksandrov &lt;nikolay@cumulusnetworks.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Stable-dep-of: bee2ef946d31 ("net: bridge: br_fdb_external_learn_add(): always set EXT_LEARN")
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 435f2e7cc0b783615d7fbcf08f5f00d289f9caeb ]

Add support for entries which are "sticky", i.e. will not change their port
if they show up from a different one. A new ndm flag is introduced for that
purpose - NTF_STICKY. We allow to set it only to non-local entries.

Signed-off-by: Nikolay Aleksandrov &lt;nikolay@cumulusnetworks.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Stable-dep-of: bee2ef946d31 ("net: bridge: br_fdb_external_learn_add(): always set EXT_LEARN")
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: busy-poll: use ktime_get_ns() instead of local_clock()</title>
<updated>2024-09-04T11:13:08+00:00</updated>
<author>
<name>Eric Dumazet</name>
<email>edumazet@google.com</email>
</author>
<published>2024-08-27T11:49:16+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=1b1f0890fb51fc50bf990a800106a133f9036f32'/>
<id>1b1f0890fb51fc50bf990a800106a133f9036f32</id>
<content type='text'>
[ Upstream commit 0870b0d8b393dde53106678a1e2cec9dfa52f9b7 ]

Typically, busy-polling durations are below 100 usec.

When/if the busy-poller thread migrates to another cpu,
local_clock() can be off by +/-2msec or more for small
values of HZ, depending on the platform.

Use ktimer_get_ns() to ensure deterministic behavior,
which is the whole point of busy-polling.

Fixes: 060212928670 ("net: add low latency socket poll")
Fixes: 9a3c71aa8024 ("net: convert low latency sockets to sched_clock()")
Fixes: 37089834528b ("sched, net: Fixup busy_loop_us_clock()")
Signed-off-by: Eric Dumazet &lt;edumazet@google.com&gt;
Cc: Mina Almasry &lt;almasrymina@google.com&gt;
Cc: Willem de Bruijn &lt;willemb@google.com&gt;
Reviewed-by: Joe Damato &lt;jdamato@fastly.com&gt;
Link: https://patch.msgid.link/20240827114916.223377-1-edumazet@google.com
Signed-off-by: Jakub Kicinski &lt;kuba@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 0870b0d8b393dde53106678a1e2cec9dfa52f9b7 ]

Typically, busy-polling durations are below 100 usec.

When/if the busy-poller thread migrates to another cpu,
local_clock() can be off by +/-2msec or more for small
values of HZ, depending on the platform.

Use ktimer_get_ns() to ensure deterministic behavior,
which is the whole point of busy-polling.

Fixes: 060212928670 ("net: add low latency socket poll")
Fixes: 9a3c71aa8024 ("net: convert low latency sockets to sched_clock()")
Fixes: 37089834528b ("sched, net: Fixup busy_loop_us_clock()")
Signed-off-by: Eric Dumazet &lt;edumazet@google.com&gt;
Cc: Mina Almasry &lt;almasrymina@google.com&gt;
Cc: Willem de Bruijn &lt;willemb@google.com&gt;
Reviewed-by: Joe Damato &lt;jdamato@fastly.com&gt;
Link: https://patch.msgid.link/20240827114916.223377-1-edumazet@google.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>fbcon: Prevent that screen size is smaller than font size</title>
<updated>2024-09-04T11:13:08+00:00</updated>
<author>
<name>Helge Deller</name>
<email>deller@gmx.de</email>
</author>
<published>2024-08-29T16:14:03+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=54eaaac622d4547b4abae7e44763b29fa0687132'/>
<id>54eaaac622d4547b4abae7e44763b29fa0687132</id>
<content type='text'>
commit e64242caef18b4a5840b0e7a9bff37abd4f4f933 upstream.

We need to prevent that users configure a screen size which is smaller than the
currently selected font size. Otherwise rendering chars on the screen will
access memory outside the graphics memory region.

This patch adds a new function fbcon_modechange_possible() which
implements this check and which later may be extended with other checks
if necessary.  The new function is called from the FBIOPUT_VSCREENINFO
ioctl handler in fbmem.c, which will return -EINVAL if userspace asked
for a too small screen size.

Signed-off-by: Helge Deller &lt;deller@gmx.de&gt;
Reviewed-by: Geert Uytterhoeven &lt;geert@linux-m68k.org&gt;
Cc: stable@vger.kernel.org # v5.4+
Signed-off-by: Hugo SIMELIERE &lt;hsimeliere.opensource@witekio.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 e64242caef18b4a5840b0e7a9bff37abd4f4f933 upstream.

We need to prevent that users configure a screen size which is smaller than the
currently selected font size. Otherwise rendering chars on the screen will
access memory outside the graphics memory region.

This patch adds a new function fbcon_modechange_possible() which
implements this check and which later may be extended with other checks
if necessary.  The new function is called from the FBIOPUT_VSCREENINFO
ioctl handler in fbmem.c, which will return -EINVAL if userspace asked
for a too small screen size.

Signed-off-by: Helge Deller &lt;deller@gmx.de&gt;
Reviewed-by: Geert Uytterhoeven &lt;geert@linux-m68k.org&gt;
Cc: stable@vger.kernel.org # v5.4+
Signed-off-by: Hugo SIMELIERE &lt;hsimeliere.opensource@witekio.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>kcm: Serialise kcm_sendmsg() for the same socket.</title>
<updated>2024-09-04T11:13:05+00:00</updated>
<author>
<name>Kuniyuki Iwashima</name>
<email>kuniyu@amazon.com</email>
</author>
<published>2024-08-15T22:04:37+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=8c9cdbf600143bd6835c8b8351e5ac956da79aec'/>
<id>8c9cdbf600143bd6835c8b8351e5ac956da79aec</id>
<content type='text'>
[ Upstream commit 807067bf014d4a3ae2cc55bd3de16f22a01eb580 ]

syzkaller reported UAF in kcm_release(). [0]

The scenario is

  1. Thread A builds a skb with MSG_MORE and sets kcm-&gt;seq_skb.

  2. Thread A resumes building skb from kcm-&gt;seq_skb but is blocked
     by sk_stream_wait_memory()

  3. Thread B calls sendmsg() concurrently, finishes building kcm-&gt;seq_skb
     and puts the skb to the write queue

  4. Thread A faces an error and finally frees skb that is already in the
     write queue

  5. kcm_release() does double-free the skb in the write queue

When a thread is building a MSG_MORE skb, another thread must not touch it.

Let's add a per-sk mutex and serialise kcm_sendmsg().

[0]:
BUG: KASAN: slab-use-after-free in __skb_unlink include/linux/skbuff.h:2366 [inline]
BUG: KASAN: slab-use-after-free in __skb_dequeue include/linux/skbuff.h:2385 [inline]
BUG: KASAN: slab-use-after-free in __skb_queue_purge_reason include/linux/skbuff.h:3175 [inline]
BUG: KASAN: slab-use-after-free in __skb_queue_purge include/linux/skbuff.h:3181 [inline]
BUG: KASAN: slab-use-after-free in kcm_release+0x170/0x4c8 net/kcm/kcmsock.c:1691
Read of size 8 at addr ffff0000ced0fc80 by task syz-executor329/6167

CPU: 1 PID: 6167 Comm: syz-executor329 Tainted: G    B              6.8.0-rc5-syzkaller-g9abbc24128bc #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
Call trace:
 dump_backtrace+0x1b8/0x1e4 arch/arm64/kernel/stacktrace.c:291
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:298
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xd0/0x124 lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:377 [inline]
 print_report+0x178/0x518 mm/kasan/report.c:488
 kasan_report+0xd8/0x138 mm/kasan/report.c:601
 __asan_report_load8_noabort+0x20/0x2c mm/kasan/report_generic.c:381
 __skb_unlink include/linux/skbuff.h:2366 [inline]
 __skb_dequeue include/linux/skbuff.h:2385 [inline]
 __skb_queue_purge_reason include/linux/skbuff.h:3175 [inline]
 __skb_queue_purge include/linux/skbuff.h:3181 [inline]
 kcm_release+0x170/0x4c8 net/kcm/kcmsock.c:1691
 __sock_release net/socket.c:659 [inline]
 sock_close+0xa4/0x1e8 net/socket.c:1421
 __fput+0x30c/0x738 fs/file_table.c:376
 ____fput+0x20/0x30 fs/file_table.c:404
 task_work_run+0x230/0x2e0 kernel/task_work.c:180
 exit_task_work include/linux/task_work.h:38 [inline]
 do_exit+0x618/0x1f64 kernel/exit.c:871
 do_group_exit+0x194/0x22c kernel/exit.c:1020
 get_signal+0x1500/0x15ec kernel/signal.c:2893
 do_signal+0x23c/0x3b44 arch/arm64/kernel/signal.c:1249
 do_notify_resume+0x74/0x1f4 arch/arm64/kernel/entry-common.c:148
 exit_to_user_mode_prepare arch/arm64/kernel/entry-common.c:169 [inline]
 exit_to_user_mode arch/arm64/kernel/entry-common.c:178 [inline]
 el0_svc+0xac/0x168 arch/arm64/kernel/entry-common.c:713
 el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:730
 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:598

Allocated by task 6166:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x40/0x78 mm/kasan/common.c:68
 kasan_save_alloc_info+0x70/0x84 mm/kasan/generic.c:626
 unpoison_slab_object mm/kasan/common.c:314 [inline]
 __kasan_slab_alloc+0x74/0x8c mm/kasan/common.c:340
 kasan_slab_alloc include/linux/kasan.h:201 [inline]
 slab_post_alloc_hook mm/slub.c:3813 [inline]
 slab_alloc_node mm/slub.c:3860 [inline]
 kmem_cache_alloc_node+0x204/0x4c0 mm/slub.c:3903
 __alloc_skb+0x19c/0x3d8 net/core/skbuff.c:641
 alloc_skb include/linux/skbuff.h:1296 [inline]
 kcm_sendmsg+0x1d3c/0x2124 net/kcm/kcmsock.c:783
 sock_sendmsg_nosec net/socket.c:730 [inline]
 __sock_sendmsg net/socket.c:745 [inline]
 sock_sendmsg+0x220/0x2c0 net/socket.c:768
 splice_to_socket+0x7cc/0xd58 fs/splice.c:889
 do_splice_from fs/splice.c:941 [inline]
 direct_splice_actor+0xec/0x1d8 fs/splice.c:1164
 splice_direct_to_actor+0x438/0xa0c fs/splice.c:1108
 do_splice_direct_actor fs/splice.c:1207 [inline]
 do_splice_direct+0x1e4/0x304 fs/splice.c:1233
 do_sendfile+0x460/0xb3c fs/read_write.c:1295
 __do_sys_sendfile64 fs/read_write.c:1362 [inline]
 __se_sys_sendfile64 fs/read_write.c:1348 [inline]
 __arm64_sys_sendfile64+0x160/0x3b4 fs/read_write.c:1348
 __invoke_syscall arch/arm64/kernel/syscall.c:37 [inline]
 invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:51
 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:136
 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:155
 el0_svc+0x54/0x168 arch/arm64/kernel/entry-common.c:712
 el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:730
 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:598

Freed by task 6167:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x40/0x78 mm/kasan/common.c:68
 kasan_save_free_info+0x5c/0x74 mm/kasan/generic.c:640
 poison_slab_object+0x124/0x18c mm/kasan/common.c:241
 __kasan_slab_free+0x3c/0x78 mm/kasan/common.c:257
 kasan_slab_free include/linux/kasan.h:184 [inline]
 slab_free_hook mm/slub.c:2121 [inline]
 slab_free mm/slub.c:4299 [inline]
 kmem_cache_free+0x15c/0x3d4 mm/slub.c:4363
 kfree_skbmem+0x10c/0x19c
 __kfree_skb net/core/skbuff.c:1109 [inline]
 kfree_skb_reason+0x240/0x6f4 net/core/skbuff.c:1144
 kfree_skb include/linux/skbuff.h:1244 [inline]
 kcm_release+0x104/0x4c8 net/kcm/kcmsock.c:1685
 __sock_release net/socket.c:659 [inline]
 sock_close+0xa4/0x1e8 net/socket.c:1421
 __fput+0x30c/0x738 fs/file_table.c:376
 ____fput+0x20/0x30 fs/file_table.c:404
 task_work_run+0x230/0x2e0 kernel/task_work.c:180
 exit_task_work include/linux/task_work.h:38 [inline]
 do_exit+0x618/0x1f64 kernel/exit.c:871
 do_group_exit+0x194/0x22c kernel/exit.c:1020
 get_signal+0x1500/0x15ec kernel/signal.c:2893
 do_signal+0x23c/0x3b44 arch/arm64/kernel/signal.c:1249
 do_notify_resume+0x74/0x1f4 arch/arm64/kernel/entry-common.c:148
 exit_to_user_mode_prepare arch/arm64/kernel/entry-common.c:169 [inline]
 exit_to_user_mode arch/arm64/kernel/entry-common.c:178 [inline]
 el0_svc+0xac/0x168 arch/arm64/kernel/entry-common.c:713
 el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:730
 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:598

The buggy address belongs to the object at ffff0000ced0fc80
 which belongs to the cache skbuff_head_cache of size 240
The buggy address is located 0 bytes inside of
 freed 240-byte region [ffff0000ced0fc80, ffff0000ced0fd70)

The buggy address belongs to the physical page:
page:00000000d35f4ae4 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x10ed0f
flags: 0x5ffc00000000800(slab|node=0|zone=2|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 05ffc00000000800 ffff0000c1cbf640 fffffdffc3423100 dead000000000004
raw: 0000000000000000 00000000000c000c 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff0000ced0fb80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff0000ced0fc00: fb fb fb fb fb fb fc fc fc fc fc fc fc fc fc fc
&gt;ffff0000ced0fc80: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                   ^
 ffff0000ced0fd00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fc fc
 ffff0000ced0fd80: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb

Fixes: ab7ac4eb9832 ("kcm: Kernel Connection Multiplexor module")
Reported-by: syzbot+b72d86aa5df17ce74c60@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=b72d86aa5df17ce74c60
Tested-by: syzbot+b72d86aa5df17ce74c60@syzkaller.appspotmail.com
Signed-off-by: Kuniyuki Iwashima &lt;kuniyu@amazon.com&gt;
Reviewed-by: Eric Dumazet &lt;edumazet@google.com&gt;
Link: https://patch.msgid.link/20240815220437.69511-1-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski &lt;kuba@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 807067bf014d4a3ae2cc55bd3de16f22a01eb580 ]

syzkaller reported UAF in kcm_release(). [0]

The scenario is

  1. Thread A builds a skb with MSG_MORE and sets kcm-&gt;seq_skb.

  2. Thread A resumes building skb from kcm-&gt;seq_skb but is blocked
     by sk_stream_wait_memory()

  3. Thread B calls sendmsg() concurrently, finishes building kcm-&gt;seq_skb
     and puts the skb to the write queue

  4. Thread A faces an error and finally frees skb that is already in the
     write queue

  5. kcm_release() does double-free the skb in the write queue

When a thread is building a MSG_MORE skb, another thread must not touch it.

Let's add a per-sk mutex and serialise kcm_sendmsg().

[0]:
BUG: KASAN: slab-use-after-free in __skb_unlink include/linux/skbuff.h:2366 [inline]
BUG: KASAN: slab-use-after-free in __skb_dequeue include/linux/skbuff.h:2385 [inline]
BUG: KASAN: slab-use-after-free in __skb_queue_purge_reason include/linux/skbuff.h:3175 [inline]
BUG: KASAN: slab-use-after-free in __skb_queue_purge include/linux/skbuff.h:3181 [inline]
BUG: KASAN: slab-use-after-free in kcm_release+0x170/0x4c8 net/kcm/kcmsock.c:1691
Read of size 8 at addr ffff0000ced0fc80 by task syz-executor329/6167

CPU: 1 PID: 6167 Comm: syz-executor329 Tainted: G    B              6.8.0-rc5-syzkaller-g9abbc24128bc #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
Call trace:
 dump_backtrace+0x1b8/0x1e4 arch/arm64/kernel/stacktrace.c:291
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:298
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xd0/0x124 lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:377 [inline]
 print_report+0x178/0x518 mm/kasan/report.c:488
 kasan_report+0xd8/0x138 mm/kasan/report.c:601
 __asan_report_load8_noabort+0x20/0x2c mm/kasan/report_generic.c:381
 __skb_unlink include/linux/skbuff.h:2366 [inline]
 __skb_dequeue include/linux/skbuff.h:2385 [inline]
 __skb_queue_purge_reason include/linux/skbuff.h:3175 [inline]
 __skb_queue_purge include/linux/skbuff.h:3181 [inline]
 kcm_release+0x170/0x4c8 net/kcm/kcmsock.c:1691
 __sock_release net/socket.c:659 [inline]
 sock_close+0xa4/0x1e8 net/socket.c:1421
 __fput+0x30c/0x738 fs/file_table.c:376
 ____fput+0x20/0x30 fs/file_table.c:404
 task_work_run+0x230/0x2e0 kernel/task_work.c:180
 exit_task_work include/linux/task_work.h:38 [inline]
 do_exit+0x618/0x1f64 kernel/exit.c:871
 do_group_exit+0x194/0x22c kernel/exit.c:1020
 get_signal+0x1500/0x15ec kernel/signal.c:2893
 do_signal+0x23c/0x3b44 arch/arm64/kernel/signal.c:1249
 do_notify_resume+0x74/0x1f4 arch/arm64/kernel/entry-common.c:148
 exit_to_user_mode_prepare arch/arm64/kernel/entry-common.c:169 [inline]
 exit_to_user_mode arch/arm64/kernel/entry-common.c:178 [inline]
 el0_svc+0xac/0x168 arch/arm64/kernel/entry-common.c:713
 el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:730
 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:598

Allocated by task 6166:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x40/0x78 mm/kasan/common.c:68
 kasan_save_alloc_info+0x70/0x84 mm/kasan/generic.c:626
 unpoison_slab_object mm/kasan/common.c:314 [inline]
 __kasan_slab_alloc+0x74/0x8c mm/kasan/common.c:340
 kasan_slab_alloc include/linux/kasan.h:201 [inline]
 slab_post_alloc_hook mm/slub.c:3813 [inline]
 slab_alloc_node mm/slub.c:3860 [inline]
 kmem_cache_alloc_node+0x204/0x4c0 mm/slub.c:3903
 __alloc_skb+0x19c/0x3d8 net/core/skbuff.c:641
 alloc_skb include/linux/skbuff.h:1296 [inline]
 kcm_sendmsg+0x1d3c/0x2124 net/kcm/kcmsock.c:783
 sock_sendmsg_nosec net/socket.c:730 [inline]
 __sock_sendmsg net/socket.c:745 [inline]
 sock_sendmsg+0x220/0x2c0 net/socket.c:768
 splice_to_socket+0x7cc/0xd58 fs/splice.c:889
 do_splice_from fs/splice.c:941 [inline]
 direct_splice_actor+0xec/0x1d8 fs/splice.c:1164
 splice_direct_to_actor+0x438/0xa0c fs/splice.c:1108
 do_splice_direct_actor fs/splice.c:1207 [inline]
 do_splice_direct+0x1e4/0x304 fs/splice.c:1233
 do_sendfile+0x460/0xb3c fs/read_write.c:1295
 __do_sys_sendfile64 fs/read_write.c:1362 [inline]
 __se_sys_sendfile64 fs/read_write.c:1348 [inline]
 __arm64_sys_sendfile64+0x160/0x3b4 fs/read_write.c:1348
 __invoke_syscall arch/arm64/kernel/syscall.c:37 [inline]
 invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:51
 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:136
 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:155
 el0_svc+0x54/0x168 arch/arm64/kernel/entry-common.c:712
 el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:730
 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:598

Freed by task 6167:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x40/0x78 mm/kasan/common.c:68
 kasan_save_free_info+0x5c/0x74 mm/kasan/generic.c:640
 poison_slab_object+0x124/0x18c mm/kasan/common.c:241
 __kasan_slab_free+0x3c/0x78 mm/kasan/common.c:257
 kasan_slab_free include/linux/kasan.h:184 [inline]
 slab_free_hook mm/slub.c:2121 [inline]
 slab_free mm/slub.c:4299 [inline]
 kmem_cache_free+0x15c/0x3d4 mm/slub.c:4363
 kfree_skbmem+0x10c/0x19c
 __kfree_skb net/core/skbuff.c:1109 [inline]
 kfree_skb_reason+0x240/0x6f4 net/core/skbuff.c:1144
 kfree_skb include/linux/skbuff.h:1244 [inline]
 kcm_release+0x104/0x4c8 net/kcm/kcmsock.c:1685
 __sock_release net/socket.c:659 [inline]
 sock_close+0xa4/0x1e8 net/socket.c:1421
 __fput+0x30c/0x738 fs/file_table.c:376
 ____fput+0x20/0x30 fs/file_table.c:404
 task_work_run+0x230/0x2e0 kernel/task_work.c:180
 exit_task_work include/linux/task_work.h:38 [inline]
 do_exit+0x618/0x1f64 kernel/exit.c:871
 do_group_exit+0x194/0x22c kernel/exit.c:1020
 get_signal+0x1500/0x15ec kernel/signal.c:2893
 do_signal+0x23c/0x3b44 arch/arm64/kernel/signal.c:1249
 do_notify_resume+0x74/0x1f4 arch/arm64/kernel/entry-common.c:148
 exit_to_user_mode_prepare arch/arm64/kernel/entry-common.c:169 [inline]
 exit_to_user_mode arch/arm64/kernel/entry-common.c:178 [inline]
 el0_svc+0xac/0x168 arch/arm64/kernel/entry-common.c:713
 el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:730
 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:598

The buggy address belongs to the object at ffff0000ced0fc80
 which belongs to the cache skbuff_head_cache of size 240
The buggy address is located 0 bytes inside of
 freed 240-byte region [ffff0000ced0fc80, ffff0000ced0fd70)

The buggy address belongs to the physical page:
page:00000000d35f4ae4 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x10ed0f
flags: 0x5ffc00000000800(slab|node=0|zone=2|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 05ffc00000000800 ffff0000c1cbf640 fffffdffc3423100 dead000000000004
raw: 0000000000000000 00000000000c000c 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff0000ced0fb80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff0000ced0fc00: fb fb fb fb fb fb fc fc fc fc fc fc fc fc fc fc
&gt;ffff0000ced0fc80: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                   ^
 ffff0000ced0fd00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fc fc
 ffff0000ced0fd80: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb

Fixes: ab7ac4eb9832 ("kcm: Kernel Connection Multiplexor module")
Reported-by: syzbot+b72d86aa5df17ce74c60@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=b72d86aa5df17ce74c60
Tested-by: syzbot+b72d86aa5df17ce74c60@syzkaller.appspotmail.com
Signed-off-by: Kuniyuki Iwashima &lt;kuniyu@amazon.com&gt;
Reviewed-by: Eric Dumazet &lt;edumazet@google.com&gt;
Link: https://patch.msgid.link/20240815220437.69511-1-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>block: use "unsigned long" for blk_validate_block_size().</title>
<updated>2024-09-04T11:13:04+00:00</updated>
<author>
<name>Tetsuo Handa</name>
<email>penguin-kernel@i-love.sakura.ne.jp</email>
</author>
<published>2021-12-18T09:41:56+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=ee12aa483f6c8cecbd5a4c794867fee0e068b822'/>
<id>ee12aa483f6c8cecbd5a4c794867fee0e068b822</id>
<content type='text'>
commit 37ae5a0f5287a52cf51242e76ccf198d02ffe495 upstream.

Since lo_simple_ioctl(LOOP_SET_BLOCK_SIZE) and ioctl(NBD_SET_BLKSIZE) pass
user-controlled "unsigned long arg" to blk_validate_block_size(),
"unsigned long" should be used for validation.

Signed-off-by: Tetsuo Handa &lt;penguin-kernel@I-love.SAKURA.ne.jp&gt;
Reviewed-by: Christoph Hellwig &lt;hch@lst.de&gt;
Link: https://lore.kernel.org/r/9ecbf057-4375-c2db-ab53-e4cc0dff953d@i-love.sakura.ne.jp
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
Signed-off-by: David Hunter &lt;david.hunter.linux@gmail.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 37ae5a0f5287a52cf51242e76ccf198d02ffe495 upstream.

Since lo_simple_ioctl(LOOP_SET_BLOCK_SIZE) and ioctl(NBD_SET_BLKSIZE) pass
user-controlled "unsigned long arg" to blk_validate_block_size(),
"unsigned long" should be used for validation.

Signed-off-by: Tetsuo Handa &lt;penguin-kernel@I-love.SAKURA.ne.jp&gt;
Reviewed-by: Christoph Hellwig &lt;hch@lst.de&gt;
Link: https://lore.kernel.org/r/9ecbf057-4375-c2db-ab53-e4cc0dff953d@i-love.sakura.ne.jp
Signed-off-by: Jens Axboe &lt;axboe@kernel.dk&gt;
Signed-off-by: David Hunter &lt;david.hunter.linux@gmail.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>overflow: Implement size_t saturating arithmetic helpers</title>
<updated>2024-09-04T11:13:00+00:00</updated>
<author>
<name>Kees Cook</name>
<email>keescook@chromium.org</email>
</author>
<published>2021-09-18T22:17:53+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=1f5cbd78177975aece64bb132948f611af2359c0'/>
<id>1f5cbd78177975aece64bb132948f611af2359c0</id>
<content type='text'>
commit e1be43d9b5d0d1310dbd90185a8e5c7145dde40f upstream.

In order to perform more open-coded replacements of common allocation
size arithmetic, the kernel needs saturating (SIZE_MAX) helpers for
multiplication, addition, and subtraction. For example, it is common in
allocators, especially on realloc, to add to an existing size:

    p = krealloc(map-&gt;patch,
                 sizeof(struct reg_sequence) * (map-&gt;patch_regs + num_regs),
                 GFP_KERNEL);

There is no existing saturating replacement for this calculation, and
just leaving the addition open coded inside array_size() could
potentially overflow as well. For example, an overflow in an expression
for a size_t argument might wrap to zero:

    array_size(anything, something_at_size_max + 1) == 0

Introduce size_mul(), size_add(), and size_sub() helpers that
implicitly promote arguments to size_t and saturated calculations for
use in allocations. With these helpers it is also possible to redefine
array_size(), array3_size(), flex_array_size(), and struct_size() in
terms of the new helpers.

As with the check_*_overflow() helpers, the new helpers use __must_check,
though what is really desired is a way to make sure that assignment is
only to a size_t lvalue. Without this, it's still possible to introduce
overflow/underflow via type conversion (i.e. from size_t to int).
Enforcing this will currently need to be left to static analysis or
future use of -Wconversion.

Additionally update the overflow unit tests to force runtime evaluation
for the pathological cases.

Cc: Rasmus Villemoes &lt;linux@rasmusvillemoes.dk&gt;
Cc: Gustavo A. R. Silva &lt;gustavoars@kernel.org&gt;
Cc: Nathan Chancellor &lt;nathan@kernel.org&gt;
Cc: Jason Gunthorpe &lt;jgg@ziepe.ca&gt;
Cc: Nick Desaulniers &lt;ndesaulniers@google.com&gt;
Cc: Leon Romanovsky &lt;leon@kernel.org&gt;
Cc: Keith Busch &lt;kbusch@kernel.org&gt;
Cc: Len Baker &lt;len.baker@gmx.com&gt;
Signed-off-by: Kees Cook &lt;keescook@chromium.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 e1be43d9b5d0d1310dbd90185a8e5c7145dde40f upstream.

In order to perform more open-coded replacements of common allocation
size arithmetic, the kernel needs saturating (SIZE_MAX) helpers for
multiplication, addition, and subtraction. For example, it is common in
allocators, especially on realloc, to add to an existing size:

    p = krealloc(map-&gt;patch,
                 sizeof(struct reg_sequence) * (map-&gt;patch_regs + num_regs),
                 GFP_KERNEL);

There is no existing saturating replacement for this calculation, and
just leaving the addition open coded inside array_size() could
potentially overflow as well. For example, an overflow in an expression
for a size_t argument might wrap to zero:

    array_size(anything, something_at_size_max + 1) == 0

Introduce size_mul(), size_add(), and size_sub() helpers that
implicitly promote arguments to size_t and saturated calculations for
use in allocations. With these helpers it is also possible to redefine
array_size(), array3_size(), flex_array_size(), and struct_size() in
terms of the new helpers.

As with the check_*_overflow() helpers, the new helpers use __must_check,
though what is really desired is a way to make sure that assignment is
only to a size_t lvalue. Without this, it's still possible to introduce
overflow/underflow via type conversion (i.e. from size_t to int).
Enforcing this will currently need to be left to static analysis or
future use of -Wconversion.

Additionally update the overflow unit tests to force runtime evaluation
for the pathological cases.

Cc: Rasmus Villemoes &lt;linux@rasmusvillemoes.dk&gt;
Cc: Gustavo A. R. Silva &lt;gustavoars@kernel.org&gt;
Cc: Nathan Chancellor &lt;nathan@kernel.org&gt;
Cc: Jason Gunthorpe &lt;jgg@ziepe.ca&gt;
Cc: Nick Desaulniers &lt;ndesaulniers@google.com&gt;
Cc: Leon Romanovsky &lt;leon@kernel.org&gt;
Cc: Keith Busch &lt;kbusch@kernel.org&gt;
Cc: Len Baker &lt;len.baker@gmx.com&gt;
Signed-off-by: Kees Cook &lt;keescook@chromium.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>overflow.h: Add flex_array_size() helper</title>
<updated>2024-09-04T11:12:59+00:00</updated>
<author>
<name>Gustavo A. R. Silva</name>
<email>gustavoars@kernel.org</email>
</author>
<published>2020-06-09T01:22:33+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=81bec94f5d864318fa4fccfd06e5449c501885b7'/>
<id>81bec94f5d864318fa4fccfd06e5449c501885b7</id>
<content type='text'>
commit b19d57d0f3cc6f1022edf94daf1d70506a09e3c2 upstream.

Add flex_array_size() helper for the calculation of the size, in bytes,
of a flexible array member contained within an enclosing structure.

Example of usage:

struct something {
	size_t count;
	struct foo items[];
};

struct something *instance;

instance = kmalloc(struct_size(instance, items, count), GFP_KERNEL);
instance-&gt;count = count;
memcpy(instance-&gt;items, src, flex_array_size(instance, items, instance-&gt;count));

The helper returns SIZE_MAX on overflow instead of wrapping around.

Additionally replaces parameter "n" with "count" in struct_size() helper
for greater clarity and unification.

Signed-off-by: Gustavo A. R. Silva &lt;gustavoars@kernel.org&gt;
Link: https://lore.kernel.org/r/20200609012233.GA3371@embeddedor
Signed-off-by: Kees Cook &lt;keescook@chromium.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 b19d57d0f3cc6f1022edf94daf1d70506a09e3c2 upstream.

Add flex_array_size() helper for the calculation of the size, in bytes,
of a flexible array member contained within an enclosing structure.

Example of usage:

struct something {
	size_t count;
	struct foo items[];
};

struct something *instance;

instance = kmalloc(struct_size(instance, items, count), GFP_KERNEL);
instance-&gt;count = count;
memcpy(instance-&gt;items, src, flex_array_size(instance, items, instance-&gt;count));

The helper returns SIZE_MAX on overflow instead of wrapping around.

Additionally replaces parameter "n" with "count" in struct_size() helper
for greater clarity and unification.

Signed-off-by: Gustavo A. R. Silva &lt;gustavoars@kernel.org&gt;
Link: https://lore.kernel.org/r/20200609012233.GA3371@embeddedor
Signed-off-by: Kees Cook &lt;keescook@chromium.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
</feed>
