linux-stable.git/net/packet, branch v5.4.185 Linux kernel stable tree af_packet: fix data-race in packet_setsockopt / packet_setsockopt 2022-02-05T11:35:37+00:00 Eric Dumazet edumazet@google.com 2022-02-01T02:23:58+00:00 4fc41403f0b6e4ac454f2ec27c05564fdbdf036b commit e42e70ad6ae2ae511a6143d2e8da929366e58bd9 upstream. When packet_setsockopt( PACKET_FANOUT_DATA ) reads po->fanout, no lock is held, meaning that another thread can change po->fanout. Given that po->fanout can only be set once during the socket lifetime (it is only cleared from fanout_release()), we can use READ_ONCE()/WRITE_ONCE() to document the race. BUG: KCSAN: data-race in packet_setsockopt / packet_setsockopt write to 0xffff88813ae8e300 of 8 bytes by task 14653 on cpu 0: fanout_add net/packet/af_packet.c:1791 [inline] packet_setsockopt+0x22fe/0x24a0 net/packet/af_packet.c:3931 __sys_setsockopt+0x209/0x2a0 net/socket.c:2180 __do_sys_setsockopt net/socket.c:2191 [inline] __se_sys_setsockopt net/socket.c:2188 [inline] __x64_sys_setsockopt+0x62/0x70 net/socket.c:2188 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae read to 0xffff88813ae8e300 of 8 bytes by task 14654 on cpu 1: packet_setsockopt+0x691/0x24a0 net/packet/af_packet.c:3935 __sys_setsockopt+0x209/0x2a0 net/socket.c:2180 __do_sys_setsockopt net/socket.c:2191 [inline] __se_sys_setsockopt net/socket.c:2188 [inline] __x64_sys_setsockopt+0x62/0x70 net/socket.c:2188 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae value changed: 0x0000000000000000 -> 0xffff888106f8c000 Reported by Kernel Concurrency Sanitizer on: CPU: 1 PID: 14654 Comm: syz-executor.3 Not tainted 5.16.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Fixes: 47dceb8ecdc1 ("packet: add classic BPF fanout mode") Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Willem de Bruijn <willemb@google.com> Reported-by: syzbot <syzkaller@googlegroups.com> Link: https://lore.kernel.org/r/20220201022358.330621-1-eric.dumazet@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit e42e70ad6ae2ae511a6143d2e8da929366e58bd9 upstream.

When packet_setsockopt( PACKET_FANOUT_DATA ) reads po->fanout,
no lock is held, meaning that another thread can change po->fanout.

Given that po->fanout can only be set once during the socket lifetime
(it is only cleared from fanout_release()), we can use
READ_ONCE()/WRITE_ONCE() to document the race.

BUG: KCSAN: data-race in packet_setsockopt / packet_setsockopt

write to 0xffff88813ae8e300 of 8 bytes by task 14653 on cpu 0:
 fanout_add net/packet/af_packet.c:1791 [inline]
 packet_setsockopt+0x22fe/0x24a0 net/packet/af_packet.c:3931
 __sys_setsockopt+0x209/0x2a0 net/socket.c:2180
 __do_sys_setsockopt net/socket.c:2191 [inline]
 __se_sys_setsockopt net/socket.c:2188 [inline]
 __x64_sys_setsockopt+0x62/0x70 net/socket.c:2188
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff88813ae8e300 of 8 bytes by task 14654 on cpu 1:
 packet_setsockopt+0x691/0x24a0 net/packet/af_packet.c:3935
 __sys_setsockopt+0x209/0x2a0 net/socket.c:2180
 __do_sys_setsockopt net/socket.c:2191 [inline]
 __se_sys_setsockopt net/socket.c:2188 [inline]
 __x64_sys_setsockopt+0x62/0x70 net/socket.c:2188
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x0000000000000000 -> 0xffff888106f8c000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 14654 Comm: syz-executor.3 Not tainted 5.16.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011

Fixes: 47dceb8ecdc1 ("packet: add classic BPF fanout mode")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Willem de Bruijn <willemb@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Link: https://lore.kernel.org/r/20220201022358.330621-1-eric.dumazet@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
net: fix information leakage in /proc/net/ptype 2022-02-01T16:24:37+00:00 Congyu Liu liu3101@purdue.edu 2022-01-18T19:20:13+00:00 e372ecd455b6ebc7720f52bf4b5f5d44d02f2092 commit 47934e06b65637c88a762d9c98329ae6e3238888 upstream. In one net namespace, after creating a packet socket without binding it to a device, users in other net namespaces can observe the new `packet_type` added by this packet socket by reading `/proc/net/ptype` file. This is minor information leakage as packet socket is namespace aware. Add a net pointer in `packet_type` to keep the net namespace of of corresponding packet socket. In `ptype_seq_show`, this net pointer must be checked when it is not NULL. Fixes: 2feb27dbe00c ("[NETNS]: Minor information leak via /proc/net/ptype file.") Signed-off-by: Congyu Liu <liu3101@purdue.edu> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
commit 47934e06b65637c88a762d9c98329ae6e3238888 upstream.

In one net namespace, after creating a packet socket without binding
it to a device, users in other net namespaces can observe the new
`packet_type` added by this packet socket by reading `/proc/net/ptype`
file. This is minor information leakage as packet socket is
namespace aware.

Add a net pointer in `packet_type` to keep the net namespace of
of corresponding packet socket. In `ptype_seq_show`, this net pointer
must be checked when it is not NULL.

Fixes: 2feb27dbe00c ("[NETNS]: Minor information leak via /proc/net/ptype file.")
Signed-off-by: Congyu Liu <liu3101@purdue.edu>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
net/packet: rx_owner_map depends on pg_vec 2021-12-22T08:29:38+00:00 Willem de Bruijn willemb@google.com 2021-12-15T14:39:37+00:00 027a13973dadb64ef4f19db56c9b619ee82c3375 [ Upstream commit ec6af094ea28f0f2dda1a6a33b14cd57e36a9755 ] Packet sockets may switch ring versions. Avoid misinterpreting state between versions, whose fields share a union. rx_owner_map is only allocated with a packet ring (pg_vec) and both are swapped together. If pg_vec is NULL, meaning no packet ring was allocated, then neither was rx_owner_map. And the field may be old state from a tpacket_v3. Fixes: 61fad6816fc1 ("net/packet: tpacket_rcv: avoid a producer race condition") Reported-by: Syzbot <syzbot+1ac0994a0a0c55151121@syzkaller.appspotmail.com> Signed-off-by: Willem de Bruijn <willemb@google.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://lore.kernel.org/r/20211215143937.106178-1-willemdebruijn.kernel@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit ec6af094ea28f0f2dda1a6a33b14cd57e36a9755 ]

Packet sockets may switch ring versions. Avoid misinterpreting state
between versions, whose fields share a union. rx_owner_map is only
allocated with a packet ring (pg_vec) and both are swapped together.
If pg_vec is NULL, meaning no packet ring was allocated, then neither
was rx_owner_map. And the field may be old state from a tpacket_v3.

Fixes: 61fad6816fc1 ("net/packet: tpacket_rcv: avoid a producer race condition")
Reported-by: Syzbot <syzbot+1ac0994a0a0c55151121@syzkaller.appspotmail.com>
Signed-off-by: Willem de Bruijn <willemb@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/20211215143937.106178-1-willemdebruijn.kernel@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
net/packet: annotate accesses to po->ifindex 2021-06-30T12:47:48+00:00 Eric Dumazet edumazet@google.com 2021-06-16T13:42:02+00:00 f12a5b48bcc8b23929308fee96297568058329aa [ Upstream commit e032f7c9c7cefffcfb79b9fc16c53011d2d9d11f ] Like prior patch, we need to annotate lockless accesses to po->ifindex For instance, packet_getname() is reading po->ifindex (twice) while another thread is able to change po->ifindex. KCSAN reported: BUG: KCSAN: data-race in packet_do_bind / packet_getname write to 0xffff888143ce3cbc of 4 bytes by task 25573 on cpu 1: packet_do_bind+0x420/0x7e0 net/packet/af_packet.c:3191 packet_bind+0xc3/0xd0 net/packet/af_packet.c:3255 __sys_bind+0x200/0x290 net/socket.c:1637 __do_sys_bind net/socket.c:1648 [inline] __se_sys_bind net/socket.c:1646 [inline] __x64_sys_bind+0x3d/0x50 net/socket.c:1646 do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47 entry_SYSCALL_64_after_hwframe+0x44/0xae read to 0xffff888143ce3cbc of 4 bytes by task 25578 on cpu 0: packet_getname+0x5b/0x1a0 net/packet/af_packet.c:3525 __sys_getsockname+0x10e/0x1a0 net/socket.c:1887 __do_sys_getsockname net/socket.c:1902 [inline] __se_sys_getsockname net/socket.c:1899 [inline] __x64_sys_getsockname+0x3e/0x50 net/socket.c:1899 do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47 entry_SYSCALL_64_after_hwframe+0x44/0xae value changed: 0x00000000 -> 0x00000001 Reported by Kernel Concurrency Sanitizer on: CPU: 0 PID: 25578 Comm: syz-executor.5 Not tainted 5.13.0-rc6-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: syzbot <syzkaller@googlegroups.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit e032f7c9c7cefffcfb79b9fc16c53011d2d9d11f ]

Like prior patch, we need to annotate lockless accesses to po->ifindex
For instance, packet_getname() is reading po->ifindex (twice) while
another thread is able to change po->ifindex.

KCSAN reported:

BUG: KCSAN: data-race in packet_do_bind / packet_getname

write to 0xffff888143ce3cbc of 4 bytes by task 25573 on cpu 1:
 packet_do_bind+0x420/0x7e0 net/packet/af_packet.c:3191
 packet_bind+0xc3/0xd0 net/packet/af_packet.c:3255
 __sys_bind+0x200/0x290 net/socket.c:1637
 __do_sys_bind net/socket.c:1648 [inline]
 __se_sys_bind net/socket.c:1646 [inline]
 __x64_sys_bind+0x3d/0x50 net/socket.c:1646
 do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff888143ce3cbc of 4 bytes by task 25578 on cpu 0:
 packet_getname+0x5b/0x1a0 net/packet/af_packet.c:3525
 __sys_getsockname+0x10e/0x1a0 net/socket.c:1887
 __do_sys_getsockname net/socket.c:1902 [inline]
 __se_sys_getsockname net/socket.c:1899 [inline]
 __x64_sys_getsockname+0x3e/0x50 net/socket.c:1899
 do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x00000000 -> 0x00000001

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 25578 Comm: syz-executor.5 Not tainted 5.13.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
net/packet: annotate accesses to po->bind 2021-06-30T12:47:48+00:00 Eric Dumazet edumazet@google.com 2021-06-16T13:42:01+00:00 cdcedd3c8683f87d157a360a3b4cbbdbdb3a6f9c [ Upstream commit c7d2ef5dd4b03ed0ee1d13bc0c55f9cf62d49bd6 ] tpacket_snd(), packet_snd(), packet_getname() and packet_seq_show() can read po->num without holding a lock. This means other threads can change po->num at the same time. KCSAN complained about this known fact [1] Add READ_ONCE()/WRITE_ONCE() to address the issue. [1] BUG: KCSAN: data-race in packet_do_bind / packet_sendmsg write to 0xffff888131a0dcc0 of 2 bytes by task 24714 on cpu 0: packet_do_bind+0x3ab/0x7e0 net/packet/af_packet.c:3181 packet_bind+0xc3/0xd0 net/packet/af_packet.c:3255 __sys_bind+0x200/0x290 net/socket.c:1637 __do_sys_bind net/socket.c:1648 [inline] __se_sys_bind net/socket.c:1646 [inline] __x64_sys_bind+0x3d/0x50 net/socket.c:1646 do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47 entry_SYSCALL_64_after_hwframe+0x44/0xae read to 0xffff888131a0dcc0 of 2 bytes by task 24719 on cpu 1: packet_snd net/packet/af_packet.c:2899 [inline] packet_sendmsg+0x317/0x3570 net/packet/af_packet.c:3040 sock_sendmsg_nosec net/socket.c:654 [inline] sock_sendmsg net/socket.c:674 [inline] ____sys_sendmsg+0x360/0x4d0 net/socket.c:2350 ___sys_sendmsg net/socket.c:2404 [inline] __sys_sendmsg+0x1ed/0x270 net/socket.c:2433 __do_sys_sendmsg net/socket.c:2442 [inline] __se_sys_sendmsg net/socket.c:2440 [inline] __x64_sys_sendmsg+0x42/0x50 net/socket.c:2440 do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47 entry_SYSCALL_64_after_hwframe+0x44/0xae value changed: 0x0000 -> 0x1200 Reported by Kernel Concurrency Sanitizer on: CPU: 1 PID: 24719 Comm: syz-executor.5 Not tainted 5.13.0-rc4-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: syzbot <syzkaller@googlegroups.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit c7d2ef5dd4b03ed0ee1d13bc0c55f9cf62d49bd6 ]

tpacket_snd(), packet_snd(), packet_getname() and packet_seq_show()
can read po->num without holding a lock. This means other threads
can change po->num at the same time.

KCSAN complained about this known fact [1]
Add READ_ONCE()/WRITE_ONCE() to address the issue.

[1] BUG: KCSAN: data-race in packet_do_bind / packet_sendmsg

write to 0xffff888131a0dcc0 of 2 bytes by task 24714 on cpu 0:
 packet_do_bind+0x3ab/0x7e0 net/packet/af_packet.c:3181
 packet_bind+0xc3/0xd0 net/packet/af_packet.c:3255
 __sys_bind+0x200/0x290 net/socket.c:1637
 __do_sys_bind net/socket.c:1648 [inline]
 __se_sys_bind net/socket.c:1646 [inline]
 __x64_sys_bind+0x3d/0x50 net/socket.c:1646
 do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff888131a0dcc0 of 2 bytes by task 24719 on cpu 1:
 packet_snd net/packet/af_packet.c:2899 [inline]
 packet_sendmsg+0x317/0x3570 net/packet/af_packet.c:3040
 sock_sendmsg_nosec net/socket.c:654 [inline]
 sock_sendmsg net/socket.c:674 [inline]
 ____sys_sendmsg+0x360/0x4d0 net/socket.c:2350
 ___sys_sendmsg net/socket.c:2404 [inline]
 __sys_sendmsg+0x1ed/0x270 net/socket.c:2433
 __do_sys_sendmsg net/socket.c:2442 [inline]
 __se_sys_sendmsg net/socket.c:2440 [inline]
 __x64_sys_sendmsg+0x42/0x50 net/socket.c:2440
 do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x0000 -> 0x1200

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 24719 Comm: syz-executor.5 Not tainted 5.13.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
net/packet: fix overflow in tpacket_rcv 2020-09-09T17:12:29+00:00 Or Cohen orcohen@paloaltonetworks.com 2020-09-04T04:05:28+00:00 bc846b58fe5cecaa2632d566355e607954779d45 [ Upstream commit acf69c946233259ab4d64f8869d4037a198c7f06 ] Using tp_reserve to calculate netoff can overflow as tp_reserve is unsigned int and netoff is unsigned short. This may lead to macoff receving a smaller value then sizeof(struct virtio_net_hdr), and if po->has_vnet_hdr is set, an out-of-bounds write will occur when calling virtio_net_hdr_from_skb. The bug is fixed by converting netoff to unsigned int and checking if it exceeds USHRT_MAX. This addresses CVE-2020-14386 Fixes: 8913336a7e8d ("packet: add PACKET_RESERVE sockopt") Signed-off-by: Or Cohen <orcohen@paloaltonetworks.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit acf69c946233259ab4d64f8869d4037a198c7f06 ]

Using tp_reserve to calculate netoff can overflow as
tp_reserve is unsigned int and netoff is unsigned short.

This may lead to macoff receving a smaller value then
sizeof(struct virtio_net_hdr), and if po->has_vnet_hdr
is set, an out-of-bounds write will occur when
calling virtio_net_hdr_from_skb.

The bug is fixed by converting netoff to unsigned int
and checking if it exceeds USHRT_MAX.

This addresses CVE-2020-14386

Fixes: 8913336a7e8d ("packet: add PACKET_RESERVE sockopt")
Signed-off-by: Or Cohen <orcohen@paloaltonetworks.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
af_packet: TPACKET_V3: fix fill status rwlock imbalance 2020-08-19T06:16:22+00:00 John Ogness john.ogness@linutronix.de 2020-08-13T19:39:25+00:00 de236de3df5754fe333367a47ee99ca6e71f0bf2 [ Upstream commit 88fd1cb80daa20af063bce81e1fad14e945a8dc4 ] After @blk_fill_in_prog_lock is acquired there is an early out vnet situation that can occur. In that case, the rwlock needs to be released. Also, since @blk_fill_in_prog_lock is only acquired when @tp_version is exactly TPACKET_V3, only release it on that exact condition as well. And finally, add sparse annotation so that it is clearer that prb_fill_curr_block() and prb_clear_blk_fill_status() are acquiring and releasing @blk_fill_in_prog_lock, respectively. sparse is still unable to understand the balance, but the warnings are now on a higher level that make more sense. Fixes: 632ca50f2cbd ("af_packet: TPACKET_V3: replace busy-wait loop") Signed-off-by: John Ogness <john.ogness@linutronix.de> Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
[ Upstream commit 88fd1cb80daa20af063bce81e1fad14e945a8dc4 ]

After @blk_fill_in_prog_lock is acquired there is an early out vnet
situation that can occur. In that case, the rwlock needs to be
released.

Also, since @blk_fill_in_prog_lock is only acquired when @tp_version
is exactly TPACKET_V3, only release it on that exact condition as
well.

And finally, add sparse annotation so that it is clearer that
prb_fill_curr_block() and prb_clear_blk_fill_status() are acquiring
and releasing @blk_fill_in_prog_lock, respectively. sparse is still
unable to understand the balance, but the warnings are now on a
higher level that make more sense.

Fixes: 632ca50f2cbd ("af_packet: TPACKET_V3: replace busy-wait loop")
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
net/packet: tpacket_rcv: avoid a producer race condition 2020-04-01T09:01:35+00:00 Willem de Bruijn willemb@google.com 2020-03-13T16:18:09+00:00 86137342fd4cf52882842aa8d1318b2661f08e8a [ Upstream commit 61fad6816fc10fb8793a925d5c1256d1c3db0cd2 ] PACKET_RX_RING can cause multiple writers to access the same slot if a fast writer wraps the ring while a slow writer is still copying. This is particularly likely with few, large, slots (e.g., GSO packets). Synchronize kernel thread ownership of rx ring slots with a bitmap. Writers acquire a slot race-free by testing tp_status TP_STATUS_KERNEL while holding the sk receive queue lock. They release this lock before copying and set tp_status to TP_STATUS_USER to release to userspace when done. During copying, another writer may take the lock, also see TP_STATUS_KERNEL, and start writing to the same slot. Introduce a new rx_owner_map bitmap with a bit per slot. To acquire a slot, test and set with the lock held. To release race-free, update tp_status and owner bit as a transaction, so take the lock again. This is the one of a variety of discussed options (see Link below): * instead of a shadow ring, embed the data in the slot itself, such as in tp_padding. But any test for this field may match a value left by userspace, causing deadlock. * avoid the lock on release. This leaves a small race if releasing the shadow slot before setting TP_STATUS_USER. The below reproducer showed that this race is not academic. If releasing the slot after tp_status, the race is more subtle. See the first link for details. * add a new tp_status TP_KERNEL_OWNED to avoid the transactional store of two fields. But, legacy applications may interpret all non-zero tp_status as owned by the user. As libpcap does. So this is possible only opt-in by newer processes. It can be added as an optional mode. * embed the struct at the tail of pg_vec to avoid extra allocation. The implementation proved no less complex than a separate field. The additional locking cost on release adds contention, no different than scaling on multicore or multiqueue h/w. In practice, below reproducer nor small packet tcpdump showed a noticeable change in perf report in cycles spent in spinlock. Where contention is problematic, packet sockets support mitigation through PACKET_FANOUT. And we can consider adding opt-in state TP_KERNEL_OWNED. Easy to reproduce by running multiple netperf or similar TCP_STREAM flows concurrently with `tcpdump -B 129 -n greater 60000`. Based on an earlier patchset by Jon Rosen. See links below. I believe this issue goes back to the introduction of tpacket_rcv, which predates git history. Link: https://www.mail-archive.com/netdev@vger.kernel.org/msg237222.html Suggested-by: Jon Rosen <jrosen@cisco.com> Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Jon Rosen <jrosen@cisco.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
[ Upstream commit 61fad6816fc10fb8793a925d5c1256d1c3db0cd2 ]

PACKET_RX_RING can cause multiple writers to access the same slot if a
fast writer wraps the ring while a slow writer is still copying. This
is particularly likely with few, large, slots (e.g., GSO packets).

Synchronize kernel thread ownership of rx ring slots with a bitmap.

Writers acquire a slot race-free by testing tp_status TP_STATUS_KERNEL
while holding the sk receive queue lock. They release this lock before
copying and set tp_status to TP_STATUS_USER to release to userspace
when done. During copying, another writer may take the lock, also see
TP_STATUS_KERNEL, and start writing to the same slot.

Introduce a new rx_owner_map bitmap with a bit per slot. To acquire a
slot, test and set with the lock held. To release race-free, update
tp_status and owner bit as a transaction, so take the lock again.

This is the one of a variety of discussed options (see Link below):

* instead of a shadow ring, embed the data in the slot itself, such as
in tp_padding. But any test for this field may match a value left by
userspace, causing deadlock.

* avoid the lock on release. This leaves a small race if releasing the
shadow slot before setting TP_STATUS_USER. The below reproducer showed
that this race is not academic. If releasing the slot after tp_status,
the race is more subtle. See the first link for details.

* add a new tp_status TP_KERNEL_OWNED to avoid the transactional store
of two fields. But, legacy applications may interpret all non-zero
tp_status as owned by the user. As libpcap does. So this is possible
only opt-in by newer processes. It can be added as an optional mode.

* embed the struct at the tail of pg_vec to avoid extra allocation.
The implementation proved no less complex than a separate field.

The additional locking cost on release adds contention, no different
than scaling on multicore or multiqueue h/w. In practice, below
reproducer nor small packet tcpdump showed a noticeable change in
perf report in cycles spent in spinlock. Where contention is
problematic, packet sockets support mitigation through PACKET_FANOUT.
And we can consider adding opt-in state TP_KERNEL_OWNED.

Easy to reproduce by running multiple netperf or similar TCP_STREAM
flows concurrently with `tcpdump -B 129 -n greater 60000`.

Based on an earlier patchset by Jon Rosen. See links below.

I believe this issue goes back to the introduction of tpacket_rcv,
which predates git history.

Link: https://www.mail-archive.com/netdev@vger.kernel.org/msg237222.html
Suggested-by: Jon Rosen <jrosen@cisco.com>
Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Jon Rosen <jrosen@cisco.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
net/packet: tpacket_rcv: do not increment ring index on drop 2020-03-18T06:17:41+00:00 Willem de Bruijn willemb@google.com 2020-03-09T15:34:35+00:00 a200e439c08bd92415f45802dbd5f535e511fd43 [ Upstream commit 46e4c421a053c36bf7a33dda2272481bcaf3eed3 ] In one error case, tpacket_rcv drops packets after incrementing the ring producer index. If this happens, it does not update tp_status to TP_STATUS_USER and thus the reader is stalled for an iteration of the ring, causing out of order arrival. The only such error path is when virtio_net_hdr_from_skb fails due to encountering an unknown GSO type. Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
[ Upstream commit 46e4c421a053c36bf7a33dda2272481bcaf3eed3 ]

In one error case, tpacket_rcv drops packets after incrementing the
ring producer index.

If this happens, it does not update tp_status to TP_STATUS_USER and
thus the reader is stalled for an iteration of the ring, causing out
of order arrival.

The only such error path is when virtio_net_hdr_from_skb fails due
to encountering an unknown GSO type.

Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
packet: fix data-race in fanout_flow_is_huge() 2020-01-26T09:01:06+00:00 Eric Dumazet edumazet@google.com 2019-11-08T13:07:46+00:00 f6d362634e1645e74a8472511f29a63a7c41cb13 [ Upstream commit b756ad928d98e5ef0b74af7546a6a31a8dadde00 ] KCSAN reported the following data-race [1] Adding a couple of READ_ONCE()/WRITE_ONCE() should silence it. Since the report hinted about multiple cpus using the history concurrently, I added a test avoiding writing on it if the victim slot already contains the desired value. [1] BUG: KCSAN: data-race in fanout_demux_rollover / fanout_demux_rollover read to 0xffff8880b01786cc of 4 bytes by task 18921 on cpu 1: fanout_flow_is_huge net/packet/af_packet.c:1303 [inline] fanout_demux_rollover+0x33e/0x3f0 net/packet/af_packet.c:1353 packet_rcv_fanout+0x34e/0x490 net/packet/af_packet.c:1453 deliver_skb net/core/dev.c:1888 [inline] dev_queue_xmit_nit+0x15b/0x540 net/core/dev.c:1958 xmit_one net/core/dev.c:3195 [inline] dev_hard_start_xmit+0x3f5/0x430 net/core/dev.c:3215 __dev_queue_xmit+0x14ab/0x1b40 net/core/dev.c:3792 dev_queue_xmit+0x21/0x30 net/core/dev.c:3825 neigh_direct_output+0x1f/0x30 net/core/neighbour.c:1530 neigh_output include/net/neighbour.h:511 [inline] ip6_finish_output2+0x7a2/0xec0 net/ipv6/ip6_output.c:116 __ip6_finish_output net/ipv6/ip6_output.c:142 [inline] __ip6_finish_output+0x2d7/0x330 net/ipv6/ip6_output.c:127 ip6_finish_output+0x41/0x160 net/ipv6/ip6_output.c:152 NF_HOOK_COND include/linux/netfilter.h:294 [inline] ip6_output+0xf2/0x280 net/ipv6/ip6_output.c:175 dst_output include/net/dst.h:436 [inline] ip6_local_out+0x74/0x90 net/ipv6/output_core.c:179 ip6_send_skb+0x53/0x110 net/ipv6/ip6_output.c:1795 udp_v6_send_skb.isra.0+0x3ec/0xa70 net/ipv6/udp.c:1173 udpv6_sendmsg+0x1906/0x1c20 net/ipv6/udp.c:1471 inet6_sendmsg+0x6d/0x90 net/ipv6/af_inet6.c:576 sock_sendmsg_nosec net/socket.c:637 [inline] sock_sendmsg+0x9f/0xc0 net/socket.c:657 ___sys_sendmsg+0x2b7/0x5d0 net/socket.c:2311 __sys_sendmmsg+0x123/0x350 net/socket.c:2413 __do_sys_sendmmsg net/socket.c:2442 [inline] __se_sys_sendmmsg net/socket.c:2439 [inline] __x64_sys_sendmmsg+0x64/0x80 net/socket.c:2439 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x44/0xa9 write to 0xffff8880b01786cc of 4 bytes by task 18922 on cpu 0: fanout_flow_is_huge net/packet/af_packet.c:1306 [inline] fanout_demux_rollover+0x3a4/0x3f0 net/packet/af_packet.c:1353 packet_rcv_fanout+0x34e/0x490 net/packet/af_packet.c:1453 deliver_skb net/core/dev.c:1888 [inline] dev_queue_xmit_nit+0x15b/0x540 net/core/dev.c:1958 xmit_one net/core/dev.c:3195 [inline] dev_hard_start_xmit+0x3f5/0x430 net/core/dev.c:3215 __dev_queue_xmit+0x14ab/0x1b40 net/core/dev.c:3792 dev_queue_xmit+0x21/0x30 net/core/dev.c:3825 neigh_direct_output+0x1f/0x30 net/core/neighbour.c:1530 neigh_output include/net/neighbour.h:511 [inline] ip6_finish_output2+0x7a2/0xec0 net/ipv6/ip6_output.c:116 __ip6_finish_output net/ipv6/ip6_output.c:142 [inline] __ip6_finish_output+0x2d7/0x330 net/ipv6/ip6_output.c:127 ip6_finish_output+0x41/0x160 net/ipv6/ip6_output.c:152 NF_HOOK_COND include/linux/netfilter.h:294 [inline] ip6_output+0xf2/0x280 net/ipv6/ip6_output.c:175 dst_output include/net/dst.h:436 [inline] ip6_local_out+0x74/0x90 net/ipv6/output_core.c:179 ip6_send_skb+0x53/0x110 net/ipv6/ip6_output.c:1795 udp_v6_send_skb.isra.0+0x3ec/0xa70 net/ipv6/udp.c:1173 udpv6_sendmsg+0x1906/0x1c20 net/ipv6/udp.c:1471 inet6_sendmsg+0x6d/0x90 net/ipv6/af_inet6.c:576 sock_sendmsg_nosec net/socket.c:637 [inline] sock_sendmsg+0x9f/0xc0 net/socket.c:657 ___sys_sendmsg+0x2b7/0x5d0 net/socket.c:2311 __sys_sendmmsg+0x123/0x350 net/socket.c:2413 __do_sys_sendmmsg net/socket.c:2442 [inline] __se_sys_sendmmsg net/socket.c:2439 [inline] __x64_sys_sendmmsg+0x64/0x80 net/socket.c:2439 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Reported by Kernel Concurrency Sanitizer on: CPU: 0 PID: 18922 Comm: syz-executor.3 Not tainted 5.4.0-rc6+ #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Fixes: 3b3a5b0aab5b ("packet: rollover huge flows before small flows") Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Willem de Bruijn <willemb@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit b756ad928d98e5ef0b74af7546a6a31a8dadde00 ]

KCSAN reported the following data-race [1]

Adding a couple of READ_ONCE()/WRITE_ONCE() should silence it.

Since the report hinted about multiple cpus using the history
concurrently, I added a test avoiding writing on it if the
victim slot already contains the desired value.

[1]

BUG: KCSAN: data-race in fanout_demux_rollover / fanout_demux_rollover

read to 0xffff8880b01786cc of 4 bytes by task 18921 on cpu 1:
 fanout_flow_is_huge net/packet/af_packet.c:1303 [inline]
 fanout_demux_rollover+0x33e/0x3f0 net/packet/af_packet.c:1353
 packet_rcv_fanout+0x34e/0x490 net/packet/af_packet.c:1453
 deliver_skb net/core/dev.c:1888 [inline]
 dev_queue_xmit_nit+0x15b/0x540 net/core/dev.c:1958
 xmit_one net/core/dev.c:3195 [inline]
 dev_hard_start_xmit+0x3f5/0x430 net/core/dev.c:3215
 __dev_queue_xmit+0x14ab/0x1b40 net/core/dev.c:3792
 dev_queue_xmit+0x21/0x30 net/core/dev.c:3825
 neigh_direct_output+0x1f/0x30 net/core/neighbour.c:1530
 neigh_output include/net/neighbour.h:511 [inline]
 ip6_finish_output2+0x7a2/0xec0 net/ipv6/ip6_output.c:116
 __ip6_finish_output net/ipv6/ip6_output.c:142 [inline]
 __ip6_finish_output+0x2d7/0x330 net/ipv6/ip6_output.c:127
 ip6_finish_output+0x41/0x160 net/ipv6/ip6_output.c:152
 NF_HOOK_COND include/linux/netfilter.h:294 [inline]
 ip6_output+0xf2/0x280 net/ipv6/ip6_output.c:175
 dst_output include/net/dst.h:436 [inline]
 ip6_local_out+0x74/0x90 net/ipv6/output_core.c:179
 ip6_send_skb+0x53/0x110 net/ipv6/ip6_output.c:1795
 udp_v6_send_skb.isra.0+0x3ec/0xa70 net/ipv6/udp.c:1173
 udpv6_sendmsg+0x1906/0x1c20 net/ipv6/udp.c:1471
 inet6_sendmsg+0x6d/0x90 net/ipv6/af_inet6.c:576
 sock_sendmsg_nosec net/socket.c:637 [inline]
 sock_sendmsg+0x9f/0xc0 net/socket.c:657
 ___sys_sendmsg+0x2b7/0x5d0 net/socket.c:2311
 __sys_sendmmsg+0x123/0x350 net/socket.c:2413
 __do_sys_sendmmsg net/socket.c:2442 [inline]
 __se_sys_sendmmsg net/socket.c:2439 [inline]
 __x64_sys_sendmmsg+0x64/0x80 net/socket.c:2439
 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

write to 0xffff8880b01786cc of 4 bytes by task 18922 on cpu 0:
 fanout_flow_is_huge net/packet/af_packet.c:1306 [inline]
 fanout_demux_rollover+0x3a4/0x3f0 net/packet/af_packet.c:1353
 packet_rcv_fanout+0x34e/0x490 net/packet/af_packet.c:1453
 deliver_skb net/core/dev.c:1888 [inline]
 dev_queue_xmit_nit+0x15b/0x540 net/core/dev.c:1958
 xmit_one net/core/dev.c:3195 [inline]
 dev_hard_start_xmit+0x3f5/0x430 net/core/dev.c:3215
 __dev_queue_xmit+0x14ab/0x1b40 net/core/dev.c:3792
 dev_queue_xmit+0x21/0x30 net/core/dev.c:3825
 neigh_direct_output+0x1f/0x30 net/core/neighbour.c:1530
 neigh_output include/net/neighbour.h:511 [inline]
 ip6_finish_output2+0x7a2/0xec0 net/ipv6/ip6_output.c:116
 __ip6_finish_output net/ipv6/ip6_output.c:142 [inline]
 __ip6_finish_output+0x2d7/0x330 net/ipv6/ip6_output.c:127
 ip6_finish_output+0x41/0x160 net/ipv6/ip6_output.c:152
 NF_HOOK_COND include/linux/netfilter.h:294 [inline]
 ip6_output+0xf2/0x280 net/ipv6/ip6_output.c:175
 dst_output include/net/dst.h:436 [inline]
 ip6_local_out+0x74/0x90 net/ipv6/output_core.c:179
 ip6_send_skb+0x53/0x110 net/ipv6/ip6_output.c:1795
 udp_v6_send_skb.isra.0+0x3ec/0xa70 net/ipv6/udp.c:1173
 udpv6_sendmsg+0x1906/0x1c20 net/ipv6/udp.c:1471
 inet6_sendmsg+0x6d/0x90 net/ipv6/af_inet6.c:576
 sock_sendmsg_nosec net/socket.c:637 [inline]
 sock_sendmsg+0x9f/0xc0 net/socket.c:657
 ___sys_sendmsg+0x2b7/0x5d0 net/socket.c:2311
 __sys_sendmmsg+0x123/0x350 net/socket.c:2413
 __do_sys_sendmmsg net/socket.c:2442 [inline]
 __se_sys_sendmmsg net/socket.c:2439 [inline]
 __x64_sys_sendmmsg+0x64/0x80 net/socket.c:2439
 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 18922 Comm: syz-executor.3 Not tainted 5.4.0-rc6+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011

Fixes: 3b3a5b0aab5b ("packet: rollover huge flows before small flows")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>