<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/net/core, branch v5.15.78</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>net, neigh: Fix null-ptr-deref in neigh_table_clear()</title>
<updated>2022-11-10T17:15:31+00:00</updated>
<author>
<name>Chen Zhongjin</name>
<email>chenzhongjin@huawei.com</email>
</author>
<published>2022-11-01T12:15:52+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=2b45d6d0c41cb9593868e476681efb1aae5078a1'/>
<id>2b45d6d0c41cb9593868e476681efb1aae5078a1</id>
<content type='text'>
[ Upstream commit f8017317cb0b279b8ab98b0f3901a2e0ac880dad ]

When IPv6 module gets initialized but hits an error in the middle,
kenel panic with:

KASAN: null-ptr-deref in range [0x0000000000000598-0x000000000000059f]
CPU: 1 PID: 361 Comm: insmod
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996)
RIP: 0010:__neigh_ifdown.isra.0+0x24b/0x370
RSP: 0018:ffff888012677908 EFLAGS: 00000202
...
Call Trace:
 &lt;TASK&gt;
 neigh_table_clear+0x94/0x2d0
 ndisc_cleanup+0x27/0x40 [ipv6]
 inet6_init+0x21c/0x2cb [ipv6]
 do_one_initcall+0xd3/0x4d0
 do_init_module+0x1ae/0x670
...
Kernel panic - not syncing: Fatal exception

When ipv6 initialization fails, it will try to cleanup and calls:

neigh_table_clear()
  neigh_ifdown(tbl, NULL)
    pneigh_queue_purge(&amp;tbl-&gt;proxy_queue, dev_net(dev == NULL))
    # dev_net(NULL) triggers null-ptr-deref.

Fix it by passing NULL to pneigh_queue_purge() in neigh_ifdown() if dev
is NULL, to make kernel not panic immediately.

Fixes: 66ba215cb513 ("neigh: fix possible DoS due to net iface start/stop loop")
Signed-off-by: Chen Zhongjin &lt;chenzhongjin@huawei.com&gt;
Reviewed-by: Eric Dumazet &lt;edumazet@google.com&gt;
Reviewed-by: Denis V. Lunev &lt;den@openvz.org&gt;
Link: https://lore.kernel.org/r/20221101121552.21890-1-chenzhongjin@huawei.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 f8017317cb0b279b8ab98b0f3901a2e0ac880dad ]

When IPv6 module gets initialized but hits an error in the middle,
kenel panic with:

KASAN: null-ptr-deref in range [0x0000000000000598-0x000000000000059f]
CPU: 1 PID: 361 Comm: insmod
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996)
RIP: 0010:__neigh_ifdown.isra.0+0x24b/0x370
RSP: 0018:ffff888012677908 EFLAGS: 00000202
...
Call Trace:
 &lt;TASK&gt;
 neigh_table_clear+0x94/0x2d0
 ndisc_cleanup+0x27/0x40 [ipv6]
 inet6_init+0x21c/0x2cb [ipv6]
 do_one_initcall+0xd3/0x4d0
 do_init_module+0x1ae/0x670
...
Kernel panic - not syncing: Fatal exception

When ipv6 initialization fails, it will try to cleanup and calls:

neigh_table_clear()
  neigh_ifdown(tbl, NULL)
    pneigh_queue_purge(&amp;tbl-&gt;proxy_queue, dev_net(dev == NULL))
    # dev_net(NULL) triggers null-ptr-deref.

Fix it by passing NULL to pneigh_queue_purge() in neigh_ifdown() if dev
is NULL, to make kernel not panic immediately.

Fixes: 66ba215cb513 ("neigh: fix possible DoS due to net iface start/stop loop")
Signed-off-by: Chen Zhongjin &lt;chenzhongjin@huawei.com&gt;
Reviewed-by: Eric Dumazet &lt;edumazet@google.com&gt;
Reviewed-by: Denis V. Lunev &lt;den@openvz.org&gt;
Link: https://lore.kernel.org/r/20221101121552.21890-1-chenzhongjin@huawei.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>net: do not sense pfmemalloc status in skb_append_pagefrags()</title>
<updated>2022-11-03T14:59:19+00:00</updated>
<author>
<name>Eric Dumazet</name>
<email>edumazet@google.com</email>
</author>
<published>2022-10-27T04:03:46+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=92b4c5c3fa810212da20088bcc6c0a77fc8607bd'/>
<id>92b4c5c3fa810212da20088bcc6c0a77fc8607bd</id>
<content type='text'>
[ Upstream commit 228ebc41dfab5b5d34cd76835ddb0ca8ee12f513 ]

skb_append_pagefrags() is used by af_unix and udp sendpage()
implementation so far.

In commit 326140063946 ("tcp: TX zerocopy should not sense
pfmemalloc status") we explained why we should not sense
pfmemalloc status for pages owned by user space.

We should also use skb_fill_page_desc_noacc()
in skb_append_pagefrags() to avoid following KCSAN report:

BUG: KCSAN: data-race in lru_add_fn / skb_append_pagefrags

write to 0xffffea00058fc1c8 of 8 bytes by task 17319 on cpu 0:
__list_add include/linux/list.h:73 [inline]
list_add include/linux/list.h:88 [inline]
lruvec_add_folio include/linux/mm_inline.h:323 [inline]
lru_add_fn+0x327/0x410 mm/swap.c:228
folio_batch_move_lru+0x1e1/0x2a0 mm/swap.c:246
lru_add_drain_cpu+0x73/0x250 mm/swap.c:669
lru_add_drain+0x21/0x60 mm/swap.c:773
free_pages_and_swap_cache+0x16/0x70 mm/swap_state.c:311
tlb_batch_pages_flush mm/mmu_gather.c:59 [inline]
tlb_flush_mmu_free mm/mmu_gather.c:256 [inline]
tlb_flush_mmu+0x5b2/0x640 mm/mmu_gather.c:263
tlb_finish_mmu+0x86/0x100 mm/mmu_gather.c:363
exit_mmap+0x190/0x4d0 mm/mmap.c:3098
__mmput+0x27/0x1b0 kernel/fork.c:1185
mmput+0x3d/0x50 kernel/fork.c:1207
copy_process+0x19fc/0x2100 kernel/fork.c:2518
kernel_clone+0x166/0x550 kernel/fork.c:2671
__do_sys_clone kernel/fork.c:2812 [inline]
__se_sys_clone kernel/fork.c:2796 [inline]
__x64_sys_clone+0xc3/0xf0 kernel/fork.c:2796
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

read to 0xffffea00058fc1c8 of 8 bytes by task 17325 on cpu 1:
page_is_pfmemalloc include/linux/mm.h:1817 [inline]
__skb_fill_page_desc include/linux/skbuff.h:2432 [inline]
skb_fill_page_desc include/linux/skbuff.h:2453 [inline]
skb_append_pagefrags+0x210/0x600 net/core/skbuff.c:3974
unix_stream_sendpage+0x45e/0x990 net/unix/af_unix.c:2338
kernel_sendpage+0x184/0x300 net/socket.c:3561
sock_sendpage+0x5a/0x70 net/socket.c:1054
pipe_to_sendpage+0x128/0x160 fs/splice.c:361
splice_from_pipe_feed fs/splice.c:415 [inline]
__splice_from_pipe+0x222/0x4d0 fs/splice.c:559
splice_from_pipe fs/splice.c:594 [inline]
generic_splice_sendpage+0x89/0xc0 fs/splice.c:743
do_splice_from fs/splice.c:764 [inline]
direct_splice_actor+0x80/0xa0 fs/splice.c:931
splice_direct_to_actor+0x305/0x620 fs/splice.c:886
do_splice_direct+0xfb/0x180 fs/splice.c:974
do_sendfile+0x3bf/0x910 fs/read_write.c:1255
__do_sys_sendfile64 fs/read_write.c:1323 [inline]
__se_sys_sendfile64 fs/read_write.c:1309 [inline]
__x64_sys_sendfile64+0x10c/0x150 fs/read_write.c:1309
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

value changed: 0x0000000000000000 -&gt; 0xffffea00058fc188

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 17325 Comm: syz-executor.0 Not tainted 6.1.0-rc1-syzkaller-00158-g440b7895c990-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/11/2022

Fixes: 326140063946 ("tcp: TX zerocopy should not sense pfmemalloc status")
Reported-by: syzbot &lt;syzkaller@googlegroups.com&gt;
Signed-off-by: Eric Dumazet &lt;edumazet@google.com&gt;
Link: https://lore.kernel.org/r/20221027040346.1104204-1-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 228ebc41dfab5b5d34cd76835ddb0ca8ee12f513 ]

skb_append_pagefrags() is used by af_unix and udp sendpage()
implementation so far.

In commit 326140063946 ("tcp: TX zerocopy should not sense
pfmemalloc status") we explained why we should not sense
pfmemalloc status for pages owned by user space.

We should also use skb_fill_page_desc_noacc()
in skb_append_pagefrags() to avoid following KCSAN report:

BUG: KCSAN: data-race in lru_add_fn / skb_append_pagefrags

write to 0xffffea00058fc1c8 of 8 bytes by task 17319 on cpu 0:
__list_add include/linux/list.h:73 [inline]
list_add include/linux/list.h:88 [inline]
lruvec_add_folio include/linux/mm_inline.h:323 [inline]
lru_add_fn+0x327/0x410 mm/swap.c:228
folio_batch_move_lru+0x1e1/0x2a0 mm/swap.c:246
lru_add_drain_cpu+0x73/0x250 mm/swap.c:669
lru_add_drain+0x21/0x60 mm/swap.c:773
free_pages_and_swap_cache+0x16/0x70 mm/swap_state.c:311
tlb_batch_pages_flush mm/mmu_gather.c:59 [inline]
tlb_flush_mmu_free mm/mmu_gather.c:256 [inline]
tlb_flush_mmu+0x5b2/0x640 mm/mmu_gather.c:263
tlb_finish_mmu+0x86/0x100 mm/mmu_gather.c:363
exit_mmap+0x190/0x4d0 mm/mmap.c:3098
__mmput+0x27/0x1b0 kernel/fork.c:1185
mmput+0x3d/0x50 kernel/fork.c:1207
copy_process+0x19fc/0x2100 kernel/fork.c:2518
kernel_clone+0x166/0x550 kernel/fork.c:2671
__do_sys_clone kernel/fork.c:2812 [inline]
__se_sys_clone kernel/fork.c:2796 [inline]
__x64_sys_clone+0xc3/0xf0 kernel/fork.c:2796
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

read to 0xffffea00058fc1c8 of 8 bytes by task 17325 on cpu 1:
page_is_pfmemalloc include/linux/mm.h:1817 [inline]
__skb_fill_page_desc include/linux/skbuff.h:2432 [inline]
skb_fill_page_desc include/linux/skbuff.h:2453 [inline]
skb_append_pagefrags+0x210/0x600 net/core/skbuff.c:3974
unix_stream_sendpage+0x45e/0x990 net/unix/af_unix.c:2338
kernel_sendpage+0x184/0x300 net/socket.c:3561
sock_sendpage+0x5a/0x70 net/socket.c:1054
pipe_to_sendpage+0x128/0x160 fs/splice.c:361
splice_from_pipe_feed fs/splice.c:415 [inline]
__splice_from_pipe+0x222/0x4d0 fs/splice.c:559
splice_from_pipe fs/splice.c:594 [inline]
generic_splice_sendpage+0x89/0xc0 fs/splice.c:743
do_splice_from fs/splice.c:764 [inline]
direct_splice_actor+0x80/0xa0 fs/splice.c:931
splice_direct_to_actor+0x305/0x620 fs/splice.c:886
do_splice_direct+0xfb/0x180 fs/splice.c:974
do_sendfile+0x3bf/0x910 fs/read_write.c:1255
__do_sys_sendfile64 fs/read_write.c:1323 [inline]
__se_sys_sendfile64 fs/read_write.c:1309 [inline]
__x64_sys_sendfile64+0x10c/0x150 fs/read_write.c:1309
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

value changed: 0x0000000000000000 -&gt; 0xffffea00058fc188

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 17325 Comm: syz-executor.0 Not tainted 6.1.0-rc1-syzkaller-00158-g440b7895c990-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/11/2022

Fixes: 326140063946 ("tcp: TX zerocopy should not sense pfmemalloc status")
Reported-by: syzbot &lt;syzkaller@googlegroups.com&gt;
Signed-off-by: Eric Dumazet &lt;edumazet@google.com&gt;
Link: https://lore.kernel.org/r/20221027040346.1104204-1-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>net: fix UAF issue in nfqnl_nf_hook_drop() when ops_init() failed</title>
<updated>2022-11-03T14:59:16+00:00</updated>
<author>
<name>Zhengchao Shao</name>
<email>shaozhengchao@huawei.com</email>
</author>
<published>2022-10-20T02:42:13+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=a1e18acb0246bfb001b08b8b1b830b5ec92a0f13'/>
<id>a1e18acb0246bfb001b08b8b1b830b5ec92a0f13</id>
<content type='text'>
[ Upstream commit d266935ac43d57586e311a087510fe6a084af742 ]

When the ops_init() interface is invoked to initialize the net, but
ops-&gt;init() fails, data is released. However, the ptr pointer in
net-&gt;gen is invalid. In this case, when nfqnl_nf_hook_drop() is invoked
to release the net, invalid address access occurs.

The process is as follows:
setup_net()
	ops_init()
		data = kzalloc(...)   ---&gt; alloc "data"
		net_assign_generic()  ---&gt; assign "date" to ptr in net-&gt;gen
		...
		ops-&gt;init()           ---&gt; failed
		...
		kfree(data);          ---&gt; ptr in net-&gt;gen is invalid
	...
	ops_exit_list()
		...
		nfqnl_nf_hook_drop()
			*q = nfnl_queue_pernet(net) ---&gt; q is invalid

The following is the Call Trace information:
BUG: KASAN: use-after-free in nfqnl_nf_hook_drop+0x264/0x280
Read of size 8 at addr ffff88810396b240 by task ip/15855
Call Trace:
&lt;TASK&gt;
dump_stack_lvl+0x8e/0xd1
print_report+0x155/0x454
kasan_report+0xba/0x1f0
nfqnl_nf_hook_drop+0x264/0x280
nf_queue_nf_hook_drop+0x8b/0x1b0
__nf_unregister_net_hook+0x1ae/0x5a0
nf_unregister_net_hooks+0xde/0x130
ops_exit_list+0xb0/0x170
setup_net+0x7ac/0xbd0
copy_net_ns+0x2e6/0x6b0
create_new_namespaces+0x382/0xa50
unshare_nsproxy_namespaces+0xa6/0x1c0
ksys_unshare+0x3a4/0x7e0
__x64_sys_unshare+0x2d/0x40
do_syscall_64+0x35/0x80
entry_SYSCALL_64_after_hwframe+0x46/0xb0
&lt;/TASK&gt;

Allocated by task 15855:
kasan_save_stack+0x1e/0x40
kasan_set_track+0x21/0x30
__kasan_kmalloc+0xa1/0xb0
__kmalloc+0x49/0xb0
ops_init+0xe7/0x410
setup_net+0x5aa/0xbd0
copy_net_ns+0x2e6/0x6b0
create_new_namespaces+0x382/0xa50
unshare_nsproxy_namespaces+0xa6/0x1c0
ksys_unshare+0x3a4/0x7e0
__x64_sys_unshare+0x2d/0x40
do_syscall_64+0x35/0x80
entry_SYSCALL_64_after_hwframe+0x46/0xb0

Freed by task 15855:
kasan_save_stack+0x1e/0x40
kasan_set_track+0x21/0x30
kasan_save_free_info+0x2a/0x40
____kasan_slab_free+0x155/0x1b0
slab_free_freelist_hook+0x11b/0x220
__kmem_cache_free+0xa4/0x360
ops_init+0xb9/0x410
setup_net+0x5aa/0xbd0
copy_net_ns+0x2e6/0x6b0
create_new_namespaces+0x382/0xa50
unshare_nsproxy_namespaces+0xa6/0x1c0
ksys_unshare+0x3a4/0x7e0
__x64_sys_unshare+0x2d/0x40
do_syscall_64+0x35/0x80
entry_SYSCALL_64_after_hwframe+0x46/0xb0

Fixes: f875bae06533 ("net: Automatically allocate per namespace data.")
Signed-off-by: Zhengchao Shao &lt;shaozhengchao@huawei.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&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 d266935ac43d57586e311a087510fe6a084af742 ]

When the ops_init() interface is invoked to initialize the net, but
ops-&gt;init() fails, data is released. However, the ptr pointer in
net-&gt;gen is invalid. In this case, when nfqnl_nf_hook_drop() is invoked
to release the net, invalid address access occurs.

The process is as follows:
setup_net()
	ops_init()
		data = kzalloc(...)   ---&gt; alloc "data"
		net_assign_generic()  ---&gt; assign "date" to ptr in net-&gt;gen
		...
		ops-&gt;init()           ---&gt; failed
		...
		kfree(data);          ---&gt; ptr in net-&gt;gen is invalid
	...
	ops_exit_list()
		...
		nfqnl_nf_hook_drop()
			*q = nfnl_queue_pernet(net) ---&gt; q is invalid

The following is the Call Trace information:
BUG: KASAN: use-after-free in nfqnl_nf_hook_drop+0x264/0x280
Read of size 8 at addr ffff88810396b240 by task ip/15855
Call Trace:
&lt;TASK&gt;
dump_stack_lvl+0x8e/0xd1
print_report+0x155/0x454
kasan_report+0xba/0x1f0
nfqnl_nf_hook_drop+0x264/0x280
nf_queue_nf_hook_drop+0x8b/0x1b0
__nf_unregister_net_hook+0x1ae/0x5a0
nf_unregister_net_hooks+0xde/0x130
ops_exit_list+0xb0/0x170
setup_net+0x7ac/0xbd0
copy_net_ns+0x2e6/0x6b0
create_new_namespaces+0x382/0xa50
unshare_nsproxy_namespaces+0xa6/0x1c0
ksys_unshare+0x3a4/0x7e0
__x64_sys_unshare+0x2d/0x40
do_syscall_64+0x35/0x80
entry_SYSCALL_64_after_hwframe+0x46/0xb0
&lt;/TASK&gt;

Allocated by task 15855:
kasan_save_stack+0x1e/0x40
kasan_set_track+0x21/0x30
__kasan_kmalloc+0xa1/0xb0
__kmalloc+0x49/0xb0
ops_init+0xe7/0x410
setup_net+0x5aa/0xbd0
copy_net_ns+0x2e6/0x6b0
create_new_namespaces+0x382/0xa50
unshare_nsproxy_namespaces+0xa6/0x1c0
ksys_unshare+0x3a4/0x7e0
__x64_sys_unshare+0x2d/0x40
do_syscall_64+0x35/0x80
entry_SYSCALL_64_after_hwframe+0x46/0xb0

Freed by task 15855:
kasan_save_stack+0x1e/0x40
kasan_set_track+0x21/0x30
kasan_save_free_info+0x2a/0x40
____kasan_slab_free+0x155/0x1b0
slab_free_freelist_hook+0x11b/0x220
__kmem_cache_free+0xa4/0x360
ops_init+0xb9/0x410
setup_net+0x5aa/0xbd0
copy_net_ns+0x2e6/0x6b0
create_new_namespaces+0x382/0xa50
unshare_nsproxy_namespaces+0xa6/0x1c0
ksys_unshare+0x3a4/0x7e0
__x64_sys_unshare+0x2d/0x40
do_syscall_64+0x35/0x80
entry_SYSCALL_64_after_hwframe+0x46/0xb0

Fixes: f875bae06533 ("net: Automatically allocate per namespace data.")
Signed-off-by: Zhengchao Shao &lt;shaozhengchao@huawei.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>udp: Update reuse-&gt;has_conns under reuseport_lock.</title>
<updated>2022-10-29T08:12:56+00:00</updated>
<author>
<name>Kuniyuki Iwashima</name>
<email>kuniyu@amazon.com</email>
</author>
<published>2022-10-14T18:26:25+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=a8df9d0428c7b2e4f0c7ab8da3803f3fdddfce4d'/>
<id>a8df9d0428c7b2e4f0c7ab8da3803f3fdddfce4d</id>
<content type='text'>
[ Upstream commit 69421bf98482d089e50799f45e48b25ce4a8d154 ]

When we call connect() for a UDP socket in a reuseport group, we have
to update sk-&gt;sk_reuseport_cb-&gt;has_conns to 1.  Otherwise, the kernel
could select a unconnected socket wrongly for packets sent to the
connected socket.

However, the current way to set has_conns is illegal and possible to
trigger that problem.  reuseport_has_conns() changes has_conns under
rcu_read_lock(), which upgrades the RCU reader to the updater.  Then,
it must do the update under the updater's lock, reuseport_lock, but
it doesn't for now.

For this reason, there is a race below where we fail to set has_conns
resulting in the wrong socket selection.  To avoid the race, let's split
the reader and updater with proper locking.

 cpu1                               cpu2
+----+                             +----+

__ip[46]_datagram_connect()        reuseport_grow()
.                                  .
|- reuseport_has_conns(sk, true)   |- more_reuse = __reuseport_alloc(more_socks_size)
|  .                               |
|  |- rcu_read_lock()
|  |- reuse = rcu_dereference(sk-&gt;sk_reuseport_cb)
|  |
|  |                               |  /* reuse-&gt;has_conns == 0 here */
|  |                               |- more_reuse-&gt;has_conns = reuse-&gt;has_conns
|  |- reuse-&gt;has_conns = 1         |  /* more_reuse-&gt;has_conns SHOULD BE 1 HERE */
|  |                               |
|  |                               |- rcu_assign_pointer(reuse-&gt;socks[i]-&gt;sk_reuseport_cb,
|  |                               |                     more_reuse)
|  `- rcu_read_unlock()            `- kfree_rcu(reuse, rcu)
|
|- sk-&gt;sk_state = TCP_ESTABLISHED

Note the likely(reuse) in reuseport_has_conns_set() is always true,
but we put the test there for ease of review.  [0]

For the record, usually, sk_reuseport_cb is changed under lock_sock().
The only exception is reuseport_grow() &amp; TCP reqsk migration case.

  1) shutdown() TCP listener, which is moved into the latter part of
     reuse-&gt;socks[] to migrate reqsk.

  2) New listen() overflows reuse-&gt;socks[] and call reuseport_grow().

  3) reuse-&gt;max_socks overflows u16 with the new listener.

  4) reuseport_grow() pops the old shutdown()ed listener from the array
     and update its sk-&gt;sk_reuseport_cb as NULL without lock_sock().

shutdown()ed TCP sk-&gt;sk_reuseport_cb can be changed without lock_sock(),
but, reuseport_has_conns_set() is called only for UDP under lock_sock(),
so likely(reuse) never be false in reuseport_has_conns_set().

[0]: https://lore.kernel.org/netdev/CANn89iLja=eQHbsM_Ta2sQF0tOGU8vAGrh_izRuuHjuO1ouUag@mail.gmail.com/

Fixes: acdcecc61285 ("udp: correct reuseport selection with connected sockets")
Signed-off-by: Kuniyuki Iwashima &lt;kuniyu@amazon.com&gt;
Link: https://lore.kernel.org/r/20221014182625.89913-1-kuniyu@amazon.com
Signed-off-by: Paolo Abeni &lt;pabeni@redhat.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 69421bf98482d089e50799f45e48b25ce4a8d154 ]

When we call connect() for a UDP socket in a reuseport group, we have
to update sk-&gt;sk_reuseport_cb-&gt;has_conns to 1.  Otherwise, the kernel
could select a unconnected socket wrongly for packets sent to the
connected socket.

However, the current way to set has_conns is illegal and possible to
trigger that problem.  reuseport_has_conns() changes has_conns under
rcu_read_lock(), which upgrades the RCU reader to the updater.  Then,
it must do the update under the updater's lock, reuseport_lock, but
it doesn't for now.

For this reason, there is a race below where we fail to set has_conns
resulting in the wrong socket selection.  To avoid the race, let's split
the reader and updater with proper locking.

 cpu1                               cpu2
+----+                             +----+

__ip[46]_datagram_connect()        reuseport_grow()
.                                  .
|- reuseport_has_conns(sk, true)   |- more_reuse = __reuseport_alloc(more_socks_size)
|  .                               |
|  |- rcu_read_lock()
|  |- reuse = rcu_dereference(sk-&gt;sk_reuseport_cb)
|  |
|  |                               |  /* reuse-&gt;has_conns == 0 here */
|  |                               |- more_reuse-&gt;has_conns = reuse-&gt;has_conns
|  |- reuse-&gt;has_conns = 1         |  /* more_reuse-&gt;has_conns SHOULD BE 1 HERE */
|  |                               |
|  |                               |- rcu_assign_pointer(reuse-&gt;socks[i]-&gt;sk_reuseport_cb,
|  |                               |                     more_reuse)
|  `- rcu_read_unlock()            `- kfree_rcu(reuse, rcu)
|
|- sk-&gt;sk_state = TCP_ESTABLISHED

Note the likely(reuse) in reuseport_has_conns_set() is always true,
but we put the test there for ease of review.  [0]

For the record, usually, sk_reuseport_cb is changed under lock_sock().
The only exception is reuseport_grow() &amp; TCP reqsk migration case.

  1) shutdown() TCP listener, which is moved into the latter part of
     reuse-&gt;socks[] to migrate reqsk.

  2) New listen() overflows reuse-&gt;socks[] and call reuseport_grow().

  3) reuse-&gt;max_socks overflows u16 with the new listener.

  4) reuseport_grow() pops the old shutdown()ed listener from the array
     and update its sk-&gt;sk_reuseport_cb as NULL without lock_sock().

shutdown()ed TCP sk-&gt;sk_reuseport_cb can be changed without lock_sock(),
but, reuseport_has_conns_set() is called only for UDP under lock_sock(),
so likely(reuse) never be false in reuseport_has_conns_set().

[0]: https://lore.kernel.org/netdev/CANn89iLja=eQHbsM_Ta2sQF0tOGU8vAGrh_izRuuHjuO1ouUag@mail.gmail.com/

Fixes: acdcecc61285 ("udp: correct reuseport selection with connected sockets")
Signed-off-by: Kuniyuki Iwashima &lt;kuniyu@amazon.com&gt;
Link: https://lore.kernel.org/r/20221014182625.89913-1-kuniyu@amazon.com
Signed-off-by: Paolo Abeni &lt;pabeni@redhat.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: If sock is dead don't access sock's sk_wq in sk_stream_wait_memory</title>
<updated>2022-10-26T10:35:37+00:00</updated>
<author>
<name>Liu Jian</name>
<email>liujian56@huawei.com</email>
</author>
<published>2022-08-23T13:37:54+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=124b7c773271f06af5a2cea694b283cdb5275cf5'/>
<id>124b7c773271f06af5a2cea694b283cdb5275cf5</id>
<content type='text'>
[ Upstream commit 3f8ef65af927db247418d4e1db49164d7a158fc5 ]

Fixes the below NULL pointer dereference:

  [...]
  [   14.471200] Call Trace:
  [   14.471562]  &lt;TASK&gt;
  [   14.471882]  lock_acquire+0x245/0x2e0
  [   14.472416]  ? remove_wait_queue+0x12/0x50
  [   14.473014]  ? _raw_spin_lock_irqsave+0x17/0x50
  [   14.473681]  _raw_spin_lock_irqsave+0x3d/0x50
  [   14.474318]  ? remove_wait_queue+0x12/0x50
  [   14.474907]  remove_wait_queue+0x12/0x50
  [   14.475480]  sk_stream_wait_memory+0x20d/0x340
  [   14.476127]  ? do_wait_intr_irq+0x80/0x80
  [   14.476704]  do_tcp_sendpages+0x287/0x600
  [   14.477283]  tcp_bpf_push+0xab/0x260
  [   14.477817]  tcp_bpf_sendmsg_redir+0x297/0x500
  [   14.478461]  ? __local_bh_enable_ip+0x77/0xe0
  [   14.479096]  tcp_bpf_send_verdict+0x105/0x470
  [   14.479729]  tcp_bpf_sendmsg+0x318/0x4f0
  [   14.480311]  sock_sendmsg+0x2d/0x40
  [   14.480822]  ____sys_sendmsg+0x1b4/0x1c0
  [   14.481390]  ? copy_msghdr_from_user+0x62/0x80
  [   14.482048]  ___sys_sendmsg+0x78/0xb0
  [   14.482580]  ? vmf_insert_pfn_prot+0x91/0x150
  [   14.483215]  ? __do_fault+0x2a/0x1a0
  [   14.483738]  ? do_fault+0x15e/0x5d0
  [   14.484246]  ? __handle_mm_fault+0x56b/0x1040
  [   14.484874]  ? lock_is_held_type+0xdf/0x130
  [   14.485474]  ? find_held_lock+0x2d/0x90
  [   14.486046]  ? __sys_sendmsg+0x41/0x70
  [   14.486587]  __sys_sendmsg+0x41/0x70
  [   14.487105]  ? intel_pmu_drain_pebs_core+0x350/0x350
  [   14.487822]  do_syscall_64+0x34/0x80
  [   14.488345]  entry_SYSCALL_64_after_hwframe+0x63/0xcd
  [...]

The test scenario has the following flow:

thread1                               thread2
-----------                           ---------------
 tcp_bpf_sendmsg
  tcp_bpf_send_verdict
   tcp_bpf_sendmsg_redir              sock_close
    tcp_bpf_push_locked                 __sock_release
     tcp_bpf_push                         //inet_release
      do_tcp_sendpages                    sock-&gt;ops-&gt;release
       sk_stream_wait_memory          	   // tcp_close
          sk_wait_event                      sk-&gt;sk_prot-&gt;close
           release_sock(__sk);
            ***
                                                lock_sock(sk);
                                                  __tcp_close
                                                    sock_orphan(sk)
                                                      sk-&gt;sk_wq  = NULL
                                                release_sock
            ****
           lock_sock(__sk);
          remove_wait_queue(sk_sleep(sk), &amp;wait);
             sk_sleep(sk)
             //NULL pointer dereference
             &amp;rcu_dereference_raw(sk-&gt;sk_wq)-&gt;wait

While waiting for memory in thread1, the socket is released with its wait
queue because thread2 has closed it. This caused by tcp_bpf_send_verdict
didn't increase the f_count of psock-&gt;sk_redir-&gt;sk_socket-&gt;file in thread1.

We should check if SOCK_DEAD flag is set on wakeup in sk_stream_wait_memory
before accessing the wait queue.

Suggested-by: Jakub Sitnicki &lt;jakub@cloudflare.com&gt;
Signed-off-by: Liu Jian &lt;liujian56@huawei.com&gt;
Signed-off-by: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Acked-by: John Fastabend &lt;john.fastabend@gmail.com&gt;
Cc: Eric Dumazet &lt;edumazet@google.com&gt;
Link: https://lore.kernel.org/bpf/20220823133755.314697-2-liujian56@huawei.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 3f8ef65af927db247418d4e1db49164d7a158fc5 ]

Fixes the below NULL pointer dereference:

  [...]
  [   14.471200] Call Trace:
  [   14.471562]  &lt;TASK&gt;
  [   14.471882]  lock_acquire+0x245/0x2e0
  [   14.472416]  ? remove_wait_queue+0x12/0x50
  [   14.473014]  ? _raw_spin_lock_irqsave+0x17/0x50
  [   14.473681]  _raw_spin_lock_irqsave+0x3d/0x50
  [   14.474318]  ? remove_wait_queue+0x12/0x50
  [   14.474907]  remove_wait_queue+0x12/0x50
  [   14.475480]  sk_stream_wait_memory+0x20d/0x340
  [   14.476127]  ? do_wait_intr_irq+0x80/0x80
  [   14.476704]  do_tcp_sendpages+0x287/0x600
  [   14.477283]  tcp_bpf_push+0xab/0x260
  [   14.477817]  tcp_bpf_sendmsg_redir+0x297/0x500
  [   14.478461]  ? __local_bh_enable_ip+0x77/0xe0
  [   14.479096]  tcp_bpf_send_verdict+0x105/0x470
  [   14.479729]  tcp_bpf_sendmsg+0x318/0x4f0
  [   14.480311]  sock_sendmsg+0x2d/0x40
  [   14.480822]  ____sys_sendmsg+0x1b4/0x1c0
  [   14.481390]  ? copy_msghdr_from_user+0x62/0x80
  [   14.482048]  ___sys_sendmsg+0x78/0xb0
  [   14.482580]  ? vmf_insert_pfn_prot+0x91/0x150
  [   14.483215]  ? __do_fault+0x2a/0x1a0
  [   14.483738]  ? do_fault+0x15e/0x5d0
  [   14.484246]  ? __handle_mm_fault+0x56b/0x1040
  [   14.484874]  ? lock_is_held_type+0xdf/0x130
  [   14.485474]  ? find_held_lock+0x2d/0x90
  [   14.486046]  ? __sys_sendmsg+0x41/0x70
  [   14.486587]  __sys_sendmsg+0x41/0x70
  [   14.487105]  ? intel_pmu_drain_pebs_core+0x350/0x350
  [   14.487822]  do_syscall_64+0x34/0x80
  [   14.488345]  entry_SYSCALL_64_after_hwframe+0x63/0xcd
  [...]

The test scenario has the following flow:

thread1                               thread2
-----------                           ---------------
 tcp_bpf_sendmsg
  tcp_bpf_send_verdict
   tcp_bpf_sendmsg_redir              sock_close
    tcp_bpf_push_locked                 __sock_release
     tcp_bpf_push                         //inet_release
      do_tcp_sendpages                    sock-&gt;ops-&gt;release
       sk_stream_wait_memory          	   // tcp_close
          sk_wait_event                      sk-&gt;sk_prot-&gt;close
           release_sock(__sk);
            ***
                                                lock_sock(sk);
                                                  __tcp_close
                                                    sock_orphan(sk)
                                                      sk-&gt;sk_wq  = NULL
                                                release_sock
            ****
           lock_sock(__sk);
          remove_wait_queue(sk_sleep(sk), &amp;wait);
             sk_sleep(sk)
             //NULL pointer dereference
             &amp;rcu_dereference_raw(sk-&gt;sk_wq)-&gt;wait

While waiting for memory in thread1, the socket is released with its wait
queue because thread2 has closed it. This caused by tcp_bpf_send_verdict
didn't increase the f_count of psock-&gt;sk_redir-&gt;sk_socket-&gt;file in thread1.

We should check if SOCK_DEAD flag is set on wakeup in sk_stream_wait_memory
before accessing the wait queue.

Suggested-by: Jakub Sitnicki &lt;jakub@cloudflare.com&gt;
Signed-off-by: Liu Jian &lt;liujian56@huawei.com&gt;
Signed-off-by: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Acked-by: John Fastabend &lt;john.fastabend@gmail.com&gt;
Cc: Eric Dumazet &lt;edumazet@google.com&gt;
Link: https://lore.kernel.org/bpf/20220823133755.314697-2-liujian56@huawei.com
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>skmsg: Schedule psock work if the cached skb exists on the psock</title>
<updated>2022-10-26T10:34:46+00:00</updated>
<author>
<name>Liu Jian</name>
<email>liujian56@huawei.com</email>
</author>
<published>2022-09-07T07:13:11+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=9233ab8198d8faea0f1b7117a0d9e405536a2aad'/>
<id>9233ab8198d8faea0f1b7117a0d9e405536a2aad</id>
<content type='text'>
[ Upstream commit bec217197b412d74168c6a42fc0f76d0cc9cad00 ]

In sk_psock_backlog function, for ingress direction skb, if no new data
packet arrives after the skb is cached, the cached skb does not have a
chance to be added to the receive queue of psock. As a result, the cached
skb cannot be received by the upper-layer application. Fix this by reschedule
the psock work to dispose the cached skb in sk_msg_recvmsg function.

Fixes: 604326b41a6f ("bpf, sockmap: convert to generic sk_msg interface")
Signed-off-by: Liu Jian &lt;liujian56@huawei.com&gt;
Signed-off-by: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Acked-by: John Fastabend &lt;john.fastabend@gmail.com&gt;
Link: https://lore.kernel.org/bpf/20220907071311.60534-1-liujian56@huawei.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 bec217197b412d74168c6a42fc0f76d0cc9cad00 ]

In sk_psock_backlog function, for ingress direction skb, if no new data
packet arrives after the skb is cached, the cached skb does not have a
chance to be added to the receive queue of psock. As a result, the cached
skb cannot be received by the upper-layer application. Fix this by reschedule
the psock work to dispose the cached skb in sk_msg_recvmsg function.

Fixes: 604326b41a6f ("bpf, sockmap: convert to generic sk_msg interface")
Signed-off-by: Liu Jian &lt;liujian56@huawei.com&gt;
Signed-off-by: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Acked-by: John Fastabend &lt;john.fastabend@gmail.com&gt;
Link: https://lore.kernel.org/bpf/20220907071311.60534-1-liujian56@huawei.com
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: core: fix flow symmetric hash</title>
<updated>2022-09-28T09:11:47+00:00</updated>
<author>
<name>Ludovic Cintrat</name>
<email>ludovic.cintrat@gatewatcher.com</email>
</author>
<published>2022-09-07T10:08:13+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=4d2f1bc9067af43ca59c7c34b6be0a847638513a'/>
<id>4d2f1bc9067af43ca59c7c34b6be0a847638513a</id>
<content type='text'>
[ Upstream commit 64ae13ed478428135cddc2f1113dff162d8112d4 ]

__flow_hash_consistentify() wrongly swaps ipv4 addresses in few cases.
This function is indirectly used by __skb_get_hash_symmetric(), which is
used to fanout packets in AF_PACKET.
Intrusion detection systems may be impacted by this issue.

__flow_hash_consistentify() computes the addresses difference then swaps
them if the difference is negative. In few cases src - dst and dst - src
are both negative.

The following snippet mimics __flow_hash_consistentify():

```
 #include &lt;stdio.h&gt;
 #include &lt;stdint.h&gt;

 int main(int argc, char** argv) {

     int diffs_d, diffd_s;
     uint32_t dst  = 0xb225a8c0; /* 178.37.168.192 --&gt; 192.168.37.178 */
     uint32_t src  = 0x3225a8c0; /*  50.37.168.192 --&gt; 192.168.37.50  */
     uint32_t dst2 = 0x3325a8c0; /*  51.37.168.192 --&gt; 192.168.37.51  */

     diffs_d = src - dst;
     diffd_s = dst - src;

     printf("src:%08x dst:%08x, diff(s-d)=%d(0x%x) diff(d-s)=%d(0x%x)\n",
             src, dst, diffs_d, diffs_d, diffd_s, diffd_s);

     diffs_d = src - dst2;
     diffd_s = dst2 - src;

     printf("src:%08x dst:%08x, diff(s-d)=%d(0x%x) diff(d-s)=%d(0x%x)\n",
             src, dst2, diffs_d, diffs_d, diffd_s, diffd_s);

     return 0;
 }
```

Results:

src:3225a8c0 dst:b225a8c0, \
    diff(s-d)=-2147483648(0x80000000) \
    diff(d-s)=-2147483648(0x80000000)

src:3225a8c0 dst:3325a8c0, \
    diff(s-d)=-16777216(0xff000000) \
    diff(d-s)=16777216(0x1000000)

In the first case the addresses differences are always &lt; 0, therefore
__flow_hash_consistentify() always swaps, thus dst-&gt;src and src-&gt;dst
packets have differents hashes.

Fixes: c3f8324188fa8 ("net: Add full IPv6 addresses to flow_keys")
Signed-off-by: Ludovic Cintrat &lt;ludovic.cintrat@gatewatcher.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&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 64ae13ed478428135cddc2f1113dff162d8112d4 ]

__flow_hash_consistentify() wrongly swaps ipv4 addresses in few cases.
This function is indirectly used by __skb_get_hash_symmetric(), which is
used to fanout packets in AF_PACKET.
Intrusion detection systems may be impacted by this issue.

__flow_hash_consistentify() computes the addresses difference then swaps
them if the difference is negative. In few cases src - dst and dst - src
are both negative.

The following snippet mimics __flow_hash_consistentify():

```
 #include &lt;stdio.h&gt;
 #include &lt;stdint.h&gt;

 int main(int argc, char** argv) {

     int diffs_d, diffd_s;
     uint32_t dst  = 0xb225a8c0; /* 178.37.168.192 --&gt; 192.168.37.178 */
     uint32_t src  = 0x3225a8c0; /*  50.37.168.192 --&gt; 192.168.37.50  */
     uint32_t dst2 = 0x3325a8c0; /*  51.37.168.192 --&gt; 192.168.37.51  */

     diffs_d = src - dst;
     diffd_s = dst - src;

     printf("src:%08x dst:%08x, diff(s-d)=%d(0x%x) diff(d-s)=%d(0x%x)\n",
             src, dst, diffs_d, diffs_d, diffd_s, diffd_s);

     diffs_d = src - dst2;
     diffd_s = dst2 - src;

     printf("src:%08x dst:%08x, diff(s-d)=%d(0x%x) diff(d-s)=%d(0x%x)\n",
             src, dst2, diffs_d, diffs_d, diffd_s, diffd_s);

     return 0;
 }
```

Results:

src:3225a8c0 dst:b225a8c0, \
    diff(s-d)=-2147483648(0x80000000) \
    diff(d-s)=-2147483648(0x80000000)

src:3225a8c0 dst:3325a8c0, \
    diff(s-d)=-16777216(0xff000000) \
    diff(d-s)=16777216(0x1000000)

In the first case the addresses differences are always &lt; 0, therefore
__flow_hash_consistentify() always swaps, thus dst-&gt;src and src-&gt;dst
packets have differents hashes.

Fixes: c3f8324188fa8 ("net: Add full IPv6 addresses to flow_keys")
Signed-off-by: Ludovic Cintrat &lt;ludovic.cintrat@gatewatcher.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>tcp: TX zerocopy should not sense pfmemalloc status</title>
<updated>2022-09-15T09:30:05+00:00</updated>
<author>
<name>Eric Dumazet</name>
<email>edumazet@google.com</email>
</author>
<published>2022-08-31T23:38:09+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=8527c9a6bf8e54fef0a8d3d7d8874a48c725c915'/>
<id>8527c9a6bf8e54fef0a8d3d7d8874a48c725c915</id>
<content type='text'>
[ Upstream commit 3261400639463a853ba2b3be8bd009c2a8089775 ]

We got a recent syzbot report [1] showing a possible misuse
of pfmemalloc page status in TCP zerocopy paths.

Indeed, for pages coming from user space or other layers,
using page_is_pfmemalloc() is moot, and possibly could give
false positives.

There has been attempts to make page_is_pfmemalloc() more robust,
but not using it in the first place in this context is probably better,
removing cpu cycles.

Note to stable teams :

You need to backport 84ce071e38a6 ("net: introduce
__skb_fill_page_desc_noacc") as a prereq.

Race is more probable after commit c07aea3ef4d4
("mm: add a signature in struct page") because page_is_pfmemalloc()
is now using low order bit from page-&gt;lru.next, which can change
more often than page-&gt;index.

Low order bit should never be set for lru.next (when used as an anchor
in LRU list), so KCSAN report is mostly a false positive.

Backporting to older kernel versions seems not necessary.

[1]
BUG: KCSAN: data-race in lru_add_fn / tcp_build_frag

write to 0xffffea0004a1d2c8 of 8 bytes by task 18600 on cpu 0:
__list_add include/linux/list.h:73 [inline]
list_add include/linux/list.h:88 [inline]
lruvec_add_folio include/linux/mm_inline.h:105 [inline]
lru_add_fn+0x440/0x520 mm/swap.c:228
folio_batch_move_lru+0x1e1/0x2a0 mm/swap.c:246
folio_batch_add_and_move mm/swap.c:263 [inline]
folio_add_lru+0xf1/0x140 mm/swap.c:490
filemap_add_folio+0xf8/0x150 mm/filemap.c:948
__filemap_get_folio+0x510/0x6d0 mm/filemap.c:1981
pagecache_get_page+0x26/0x190 mm/folio-compat.c:104
grab_cache_page_write_begin+0x2a/0x30 mm/folio-compat.c:116
ext4_da_write_begin+0x2dd/0x5f0 fs/ext4/inode.c:2988
generic_perform_write+0x1d4/0x3f0 mm/filemap.c:3738
ext4_buffered_write_iter+0x235/0x3e0 fs/ext4/file.c:270
ext4_file_write_iter+0x2e3/0x1210
call_write_iter include/linux/fs.h:2187 [inline]
new_sync_write fs/read_write.c:491 [inline]
vfs_write+0x468/0x760 fs/read_write.c:578
ksys_write+0xe8/0x1a0 fs/read_write.c:631
__do_sys_write fs/read_write.c:643 [inline]
__se_sys_write fs/read_write.c:640 [inline]
__x64_sys_write+0x3e/0x50 fs/read_write.c:640
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

read to 0xffffea0004a1d2c8 of 8 bytes by task 18611 on cpu 1:
page_is_pfmemalloc include/linux/mm.h:1740 [inline]
__skb_fill_page_desc include/linux/skbuff.h:2422 [inline]
skb_fill_page_desc include/linux/skbuff.h:2443 [inline]
tcp_build_frag+0x613/0xb20 net/ipv4/tcp.c:1018
do_tcp_sendpages+0x3e8/0xaf0 net/ipv4/tcp.c:1075
tcp_sendpage_locked net/ipv4/tcp.c:1140 [inline]
tcp_sendpage+0x89/0xb0 net/ipv4/tcp.c:1150
inet_sendpage+0x7f/0xc0 net/ipv4/af_inet.c:833
kernel_sendpage+0x184/0x300 net/socket.c:3561
sock_sendpage+0x5a/0x70 net/socket.c:1054
pipe_to_sendpage+0x128/0x160 fs/splice.c:361
splice_from_pipe_feed fs/splice.c:415 [inline]
__splice_from_pipe+0x222/0x4d0 fs/splice.c:559
splice_from_pipe fs/splice.c:594 [inline]
generic_splice_sendpage+0x89/0xc0 fs/splice.c:743
do_splice_from fs/splice.c:764 [inline]
direct_splice_actor+0x80/0xa0 fs/splice.c:931
splice_direct_to_actor+0x305/0x620 fs/splice.c:886
do_splice_direct+0xfb/0x180 fs/splice.c:974
do_sendfile+0x3bf/0x910 fs/read_write.c:1249
__do_sys_sendfile64 fs/read_write.c:1317 [inline]
__se_sys_sendfile64 fs/read_write.c:1303 [inline]
__x64_sys_sendfile64+0x10c/0x150 fs/read_write.c:1303
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

value changed: 0x0000000000000000 -&gt; 0xffffea0004a1d288

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 18611 Comm: syz-executor.4 Not tainted 6.0.0-rc2-syzkaller-00248-ge022620b5d05-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/22/2022

Fixes: c07aea3ef4d4 ("mm: add a signature in struct page")
Reported-by: syzbot &lt;syzkaller@googlegroups.com&gt;
Signed-off-by: Eric Dumazet &lt;edumazet@google.com&gt;
Cc: Shakeel Butt &lt;shakeelb@google.com&gt;
Reviewed-by: Shakeel Butt &lt;shakeelb@google.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&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 3261400639463a853ba2b3be8bd009c2a8089775 ]

We got a recent syzbot report [1] showing a possible misuse
of pfmemalloc page status in TCP zerocopy paths.

Indeed, for pages coming from user space or other layers,
using page_is_pfmemalloc() is moot, and possibly could give
false positives.

There has been attempts to make page_is_pfmemalloc() more robust,
but not using it in the first place in this context is probably better,
removing cpu cycles.

Note to stable teams :

You need to backport 84ce071e38a6 ("net: introduce
__skb_fill_page_desc_noacc") as a prereq.

Race is more probable after commit c07aea3ef4d4
("mm: add a signature in struct page") because page_is_pfmemalloc()
is now using low order bit from page-&gt;lru.next, which can change
more often than page-&gt;index.

Low order bit should never be set for lru.next (when used as an anchor
in LRU list), so KCSAN report is mostly a false positive.

Backporting to older kernel versions seems not necessary.

[1]
BUG: KCSAN: data-race in lru_add_fn / tcp_build_frag

write to 0xffffea0004a1d2c8 of 8 bytes by task 18600 on cpu 0:
__list_add include/linux/list.h:73 [inline]
list_add include/linux/list.h:88 [inline]
lruvec_add_folio include/linux/mm_inline.h:105 [inline]
lru_add_fn+0x440/0x520 mm/swap.c:228
folio_batch_move_lru+0x1e1/0x2a0 mm/swap.c:246
folio_batch_add_and_move mm/swap.c:263 [inline]
folio_add_lru+0xf1/0x140 mm/swap.c:490
filemap_add_folio+0xf8/0x150 mm/filemap.c:948
__filemap_get_folio+0x510/0x6d0 mm/filemap.c:1981
pagecache_get_page+0x26/0x190 mm/folio-compat.c:104
grab_cache_page_write_begin+0x2a/0x30 mm/folio-compat.c:116
ext4_da_write_begin+0x2dd/0x5f0 fs/ext4/inode.c:2988
generic_perform_write+0x1d4/0x3f0 mm/filemap.c:3738
ext4_buffered_write_iter+0x235/0x3e0 fs/ext4/file.c:270
ext4_file_write_iter+0x2e3/0x1210
call_write_iter include/linux/fs.h:2187 [inline]
new_sync_write fs/read_write.c:491 [inline]
vfs_write+0x468/0x760 fs/read_write.c:578
ksys_write+0xe8/0x1a0 fs/read_write.c:631
__do_sys_write fs/read_write.c:643 [inline]
__se_sys_write fs/read_write.c:640 [inline]
__x64_sys_write+0x3e/0x50 fs/read_write.c:640
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

read to 0xffffea0004a1d2c8 of 8 bytes by task 18611 on cpu 1:
page_is_pfmemalloc include/linux/mm.h:1740 [inline]
__skb_fill_page_desc include/linux/skbuff.h:2422 [inline]
skb_fill_page_desc include/linux/skbuff.h:2443 [inline]
tcp_build_frag+0x613/0xb20 net/ipv4/tcp.c:1018
do_tcp_sendpages+0x3e8/0xaf0 net/ipv4/tcp.c:1075
tcp_sendpage_locked net/ipv4/tcp.c:1140 [inline]
tcp_sendpage+0x89/0xb0 net/ipv4/tcp.c:1150
inet_sendpage+0x7f/0xc0 net/ipv4/af_inet.c:833
kernel_sendpage+0x184/0x300 net/socket.c:3561
sock_sendpage+0x5a/0x70 net/socket.c:1054
pipe_to_sendpage+0x128/0x160 fs/splice.c:361
splice_from_pipe_feed fs/splice.c:415 [inline]
__splice_from_pipe+0x222/0x4d0 fs/splice.c:559
splice_from_pipe fs/splice.c:594 [inline]
generic_splice_sendpage+0x89/0xc0 fs/splice.c:743
do_splice_from fs/splice.c:764 [inline]
direct_splice_actor+0x80/0xa0 fs/splice.c:931
splice_direct_to_actor+0x305/0x620 fs/splice.c:886
do_splice_direct+0xfb/0x180 fs/splice.c:974
do_sendfile+0x3bf/0x910 fs/read_write.c:1249
__do_sys_sendfile64 fs/read_write.c:1317 [inline]
__se_sys_sendfile64 fs/read_write.c:1303 [inline]
__x64_sys_sendfile64+0x10c/0x150 fs/read_write.c:1303
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

value changed: 0x0000000000000000 -&gt; 0xffffea0004a1d288

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 18611 Comm: syz-executor.4 Not tainted 6.0.0-rc2-syzkaller-00248-ge022620b5d05-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/22/2022

Fixes: c07aea3ef4d4 ("mm: add a signature in struct page")
Reported-by: syzbot &lt;syzkaller@googlegroups.com&gt;
Signed-off-by: Eric Dumazet &lt;edumazet@google.com&gt;
Cc: Shakeel Butt &lt;shakeelb@google.com&gt;
Reviewed-by: Shakeel Butt &lt;shakeelb@google.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net/core/skbuff: Check the return value of skb_copy_bits()</title>
<updated>2022-09-15T09:30:01+00:00</updated>
<author>
<name>lily</name>
<email>floridsleeves@gmail.com</email>
</author>
<published>2022-08-23T05:44:11+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=0b7058067eb8ec143f415a42d6909a28f166de5f'/>
<id>0b7058067eb8ec143f415a42d6909a28f166de5f</id>
<content type='text'>
[ Upstream commit c624c58e08b15105662b9ab9be23d14a6b945a49 ]

skb_copy_bits() could fail, which requires a check on the return
value.

Signed-off-by: Li Zhong &lt;floridsleeves@gmail.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&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 c624c58e08b15105662b9ab9be23d14a6b945a49 ]

skb_copy_bits() could fail, which requires a check on the return
value.

Signed-off-by: Li Zhong &lt;floridsleeves@gmail.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>skmsg: Fix wrong last sg check in sk_msg_recvmsg()</title>
<updated>2022-09-08T10:28:01+00:00</updated>
<author>
<name>Liu Jian</name>
<email>liujian56@huawei.com</email>
</author>
<published>2022-08-09T09:49:15+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=de22cba333d8699ad77e79f862fe1320cb1284de'/>
<id>de22cba333d8699ad77e79f862fe1320cb1284de</id>
<content type='text'>
[ Upstream commit 583585e48d965338e73e1eb383768d16e0922d73 ]

Fix one kernel NULL pointer dereference as below:

[  224.462334] Call Trace:
[  224.462394]  __tcp_bpf_recvmsg+0xd3/0x380
[  224.462441]  ? sock_has_perm+0x78/0xa0
[  224.462463]  tcp_bpf_recvmsg+0x12e/0x220
[  224.462494]  inet_recvmsg+0x5b/0xd0
[  224.462534]  __sys_recvfrom+0xc8/0x130
[  224.462574]  ? syscall_trace_enter+0x1df/0x2e0
[  224.462606]  ? __do_page_fault+0x2de/0x500
[  224.462635]  __x64_sys_recvfrom+0x24/0x30
[  224.462660]  do_syscall_64+0x5d/0x1d0
[  224.462709]  entry_SYSCALL_64_after_hwframe+0x65/0xca

In commit 9974d37ea75f ("skmsg: Fix invalid last sg check in
sk_msg_recvmsg()"), we change last sg check to sg_is_last(),
but in sockmap redirection case (without stream_parser/stream_verdict/
skb_verdict), we did not mark the end of the scatterlist. Check the
sk_msg_alloc, sk_msg_page_add, and bpf_msg_push_data functions, they all
do not mark the end of sg. They are expected to use sg.end for end
judgment. So the judgment of '(i != msg_rx-&gt;sg.end)' is added back here.

Fixes: 9974d37ea75f ("skmsg: Fix invalid last sg check in sk_msg_recvmsg()")
Signed-off-by: Liu Jian &lt;liujian56@huawei.com&gt;
Signed-off-by: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Acked-by: John Fastabend &lt;john.fastabend@gmail.com&gt;
Acked-by: Jakub Sitnicki &lt;jakub@cloudflare.com&gt;
Link: https://lore.kernel.org/bpf/20220809094915.150391-1-liujian56@huawei.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 583585e48d965338e73e1eb383768d16e0922d73 ]

Fix one kernel NULL pointer dereference as below:

[  224.462334] Call Trace:
[  224.462394]  __tcp_bpf_recvmsg+0xd3/0x380
[  224.462441]  ? sock_has_perm+0x78/0xa0
[  224.462463]  tcp_bpf_recvmsg+0x12e/0x220
[  224.462494]  inet_recvmsg+0x5b/0xd0
[  224.462534]  __sys_recvfrom+0xc8/0x130
[  224.462574]  ? syscall_trace_enter+0x1df/0x2e0
[  224.462606]  ? __do_page_fault+0x2de/0x500
[  224.462635]  __x64_sys_recvfrom+0x24/0x30
[  224.462660]  do_syscall_64+0x5d/0x1d0
[  224.462709]  entry_SYSCALL_64_after_hwframe+0x65/0xca

In commit 9974d37ea75f ("skmsg: Fix invalid last sg check in
sk_msg_recvmsg()"), we change last sg check to sg_is_last(),
but in sockmap redirection case (without stream_parser/stream_verdict/
skb_verdict), we did not mark the end of the scatterlist. Check the
sk_msg_alloc, sk_msg_page_add, and bpf_msg_push_data functions, they all
do not mark the end of sg. They are expected to use sg.end for end
judgment. So the judgment of '(i != msg_rx-&gt;sg.end)' is added back here.

Fixes: 9974d37ea75f ("skmsg: Fix invalid last sg check in sk_msg_recvmsg()")
Signed-off-by: Liu Jian &lt;liujian56@huawei.com&gt;
Signed-off-by: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Acked-by: John Fastabend &lt;john.fastabend@gmail.com&gt;
Acked-by: Jakub Sitnicki &lt;jakub@cloudflare.com&gt;
Link: https://lore.kernel.org/bpf/20220809094915.150391-1-liujian56@huawei.com
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
</feed>
