linux.git/net, branch v5.17.6 Clone of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git netfilter: nft_socket: only do sk lookups when indev is available 2022-05-09T07:16:32+00:00 Florian Westphal fw@strlen.de 2022-04-28T07:39:21+00:00 6da4fe00bcde3038076d501e122e0fd20626dab0 commit 743b83f15d4069ea57c3e40996bf4a1077e0cdc1 upstream. Check if the incoming interface is available and NFT_BREAK in case neither skb->sk nor input device are set. Because nf_sk_lookup_slow*() assume packet headers are in the 'in' direction, use in postrouting is not going to yield a meaningful result. Same is true for the forward chain, so restrict the use to prerouting, input and output. Use in output work if a socket is already attached to the skb. Fixes: 554ced0a6e29 ("netfilter: nf_tables: add support for native socket matching") Reported-and-tested-by: Topi Miettinen <toiwoton@gmail.com> Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 743b83f15d4069ea57c3e40996bf4a1077e0cdc1 upstream.

Check if the incoming interface is available and NFT_BREAK
in case neither skb->sk nor input device are set.

Because nf_sk_lookup_slow*() assume packet headers are in the
'in' direction, use in postrouting is not going to yield a meaningful
result.  Same is true for the forward chain, so restrict the use
to prerouting, input and output.

Use in output work if a socket is already attached to the skb.

Fixes: 554ced0a6e29 ("netfilter: nf_tables: add support for native socket matching")
Reported-and-tested-by: Topi Miettinen <toiwoton@gmail.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
netfilter: Update ip6_route_me_harder to consider L3 domain 2022-05-09T07:16:29+00:00 Martin Willi martin@strongswan.org 2022-04-19T13:47:00+00:00 57a02313d93011a20d4a097c5c0a5927e191054a commit 8ddffdb9442a9d60b4a6e679ac48d7d21403a674 upstream. The commit referenced below fixed packet re-routing if Netfilter mangles a routing key property of a packet and the packet is routed in a VRF L3 domain. The fix, however, addressed IPv4 re-routing, only. This commit applies the same behavior for IPv6. While at it, untangle the nested ternary operator to make the code more readable. Fixes: 6d8b49c3a3a3 ("netfilter: Update ip_route_me_harder to consider L3 domain") Cc: stable@vger.kernel.org Signed-off-by: Martin Willi <martin@strongswan.org> Reviewed-by: David Ahern <dsahern@kernel.org> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 8ddffdb9442a9d60b4a6e679ac48d7d21403a674 upstream.

The commit referenced below fixed packet re-routing if Netfilter mangles
a routing key property of a packet and the packet is routed in a VRF L3
domain. The fix, however, addressed IPv4 re-routing, only.

This commit applies the same behavior for IPv6. While at it, untangle
the nested ternary operator to make the code more readable.

Fixes: 6d8b49c3a3a3 ("netfilter: Update ip_route_me_harder to consider L3 domain")
Cc: stable@vger.kernel.org
Signed-off-by: Martin Willi <martin@strongswan.org>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tcp: fix F-RTO may not work correctly when receiving DSACK 2022-05-09T07:16:26+00:00 Pengcheng Yang yangpc@wangsu.com 2022-04-26T10:03:39+00:00 254ca186d553beb9bf0762cbb5cc604c24d44760 [ Upstream commit d9157f6806d1499e173770df1f1b234763de5c79 ] Currently DSACK is regarded as a dupack, which may cause F-RTO to incorrectly enter "loss was real" when receiving DSACK. Packetdrill to demonstrate: // Enable F-RTO and TLP 0 `sysctl -q net.ipv4.tcp_frto=2` 0 `sysctl -q net.ipv4.tcp_early_retrans=3` 0 `sysctl -q net.ipv4.tcp_congestion_control=cubic` // Establish a connection +0 socket(..., SOCK_STREAM, IPPROTO_TCP) = 3 +0 setsockopt(3, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0 +0 bind(3, ..., ...) = 0 +0 listen(3, 1) = 0 // RTT 10ms, RTO 210ms +.1 < S 0:0(0) win 32792 <mss 1000,sackOK,nop,nop,nop,wscale 7> +0 > S. 0:0(0) ack 1 <...> +.01 < . 1:1(0) ack 1 win 257 +0 accept(3, ..., ...) = 4 // Send 2 data segments +0 write(4, ..., 2000) = 2000 +0 > P. 1:2001(2000) ack 1 // TLP +.022 > P. 1001:2001(1000) ack 1 // Continue to send 8 data segments +0 write(4, ..., 10000) = 10000 +0 > P. 2001:10001(8000) ack 1 // RTO +.188 > . 1:1001(1000) ack 1 // The original data is acked and new data is sent(F-RTO step 2.b) +0 < . 1:1(0) ack 2001 win 257 +0 > P. 10001:12001(2000) ack 1 // D-SACK caused by TLP is regarded as a dupack, this results in // the incorrect judgment of "loss was real"(F-RTO step 3.a) +.022 < . 1:1(0) ack 2001 win 257 <sack 1001:2001,nop,nop> // Never-retransmitted data(3001:4001) are acked and // expect to switch to open state(F-RTO step 3.b) +0 < . 1:1(0) ack 4001 win 257 +0 %{ assert tcpi_ca_state == 0, tcpi_ca_state }% Fixes: e33099f96d99 ("tcp: implement RFC5682 F-RTO") Signed-off-by: Pengcheng Yang <yangpc@wangsu.com> Acked-by: Neal Cardwell <ncardwell@google.com> Tested-by: Neal Cardwell <ncardwell@google.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://lore.kernel.org/r/1650967419-2150-1-git-send-email-yangpc@wangsu.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit d9157f6806d1499e173770df1f1b234763de5c79 ]

Currently DSACK is regarded as a dupack, which may cause
F-RTO to incorrectly enter "loss was real" when receiving
DSACK.

Packetdrill to demonstrate:

// Enable F-RTO and TLP
    0 `sysctl -q net.ipv4.tcp_frto=2`
    0 `sysctl -q net.ipv4.tcp_early_retrans=3`
    0 `sysctl -q net.ipv4.tcp_congestion_control=cubic`

// Establish a connection
   +0 socket(..., SOCK_STREAM, IPPROTO_TCP) = 3
   +0 setsockopt(3, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0
   +0 bind(3, ..., ...) = 0
   +0 listen(3, 1) = 0

// RTT 10ms, RTO 210ms
  +.1 < S 0:0(0) win 32792 <mss 1000,sackOK,nop,nop,nop,wscale 7>
   +0 > S. 0:0(0) ack 1 <...>
 +.01 < . 1:1(0) ack 1 win 257
   +0 accept(3, ..., ...) = 4

// Send 2 data segments
   +0 write(4, ..., 2000) = 2000
   +0 > P. 1:2001(2000) ack 1

// TLP
+.022 > P. 1001:2001(1000) ack 1

// Continue to send 8 data segments
   +0 write(4, ..., 10000) = 10000
   +0 > P. 2001:10001(8000) ack 1

// RTO
+.188 > . 1:1001(1000) ack 1

// The original data is acked and new data is sent(F-RTO step 2.b)
   +0 < . 1:1(0) ack 2001 win 257
   +0 > P. 10001:12001(2000) ack 1

// D-SACK caused by TLP is regarded as a dupack, this results in
// the incorrect judgment of "loss was real"(F-RTO step 3.a)
+.022 < . 1:1(0) ack 2001 win 257 <sack 1001:2001,nop,nop>

// Never-retransmitted data(3001:4001) are acked and
// expect to switch to open state(F-RTO step 3.b)
   +0 < . 1:1(0) ack 4001 win 257
+0 %{ assert tcpi_ca_state == 0, tcpi_ca_state }%

Fixes: e33099f96d99 ("tcp: implement RFC5682 F-RTO")
Signed-off-by: Pengcheng Yang <yangpc@wangsu.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Tested-by: Neal Cardwell <ncardwell@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/1650967419-2150-1-git-send-email-yangpc@wangsu.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
tls: Skip tls_append_frag on zero copy size 2022-05-09T07:16:25+00:00 Maxim Mikityanskiy maximmi@nvidia.com 2022-04-26T15:49:49+00:00 63c15be9dacd54309933c39b3a0b8bfb000308e1 [ Upstream commit a0df71948e9548de819a6f1da68f5f1742258a52 ] Calling tls_append_frag when max_open_record_len == record->len might add an empty fragment to the TLS record if the call happens to be on the page boundary. Normally tls_append_frag coalesces the zero-sized fragment to the previous one, but not if it's on page boundary. If a resync happens then, the mlx5 driver posts dump WQEs in tx_post_resync_dump, and the empty fragment may become a data segment with byte_count == 0, which will confuse the NIC and lead to a CQE error. This commit fixes the described issue by skipping tls_append_frag on zero size to avoid adding empty fragments. The fix is not in the driver, because an empty fragment is hardly the desired behavior. Fixes: e8f69799810c ("net/tls: Add generic NIC offload infrastructure") Signed-off-by: Maxim Mikityanskiy <maximmi@nvidia.com> Reviewed-by: Tariq Toukan <tariqt@nvidia.com> Link: https://lore.kernel.org/r/20220426154949.159055-1-maximmi@nvidia.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit a0df71948e9548de819a6f1da68f5f1742258a52 ]

Calling tls_append_frag when max_open_record_len == record->len might
add an empty fragment to the TLS record if the call happens to be on the
page boundary. Normally tls_append_frag coalesces the zero-sized
fragment to the previous one, but not if it's on page boundary.

If a resync happens then, the mlx5 driver posts dump WQEs in
tx_post_resync_dump, and the empty fragment may become a data segment
with byte_count == 0, which will confuse the NIC and lead to a CQE
error.

This commit fixes the described issue by skipping tls_append_frag on
zero size to avoid adding empty fragments. The fix is not in the driver,
because an empty fragment is hardly the desired behavior.

Fixes: e8f69799810c ("net/tls: Add generic NIC offload infrastructure")
Signed-off-by: Maxim Mikityanskiy <maximmi@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Link: https://lore.kernel.org/r/20220426154949.159055-1-maximmi@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
netfilter: conntrack: fix udp offload timeout sysctl 2022-05-09T07:16:25+00:00 Volodymyr Mytnyk volodymyr.mytnyk@plvision.eu 2022-04-27T11:09:00+00:00 697b486ee6eb5c4f4649ec03fbcae5c0189c80c7 [ Upstream commit 626873c446f7559d5af8b48cefad903ffd85cf4e ] `nf_flowtable_udp_timeout` sysctl option is available only if CONFIG_NFT_FLOW_OFFLOAD enabled. But infra for this flow offload UDP timeout was added under CONFIG_NF_FLOW_TABLE config option. So, if you have CONFIG_NFT_FLOW_OFFLOAD disabled and CONFIG_NF_FLOW_TABLE enabled, the `nf_flowtable_udp_timeout` is not present in sysfs. Please note, that TCP flow offload timeout sysctl option is present even CONFIG_NFT_FLOW_OFFLOAD is disabled. I suppose it was a typo in commit that adds UDP flow offload timeout and CONFIG_NF_FLOW_TABLE should be used instead. Fixes: 975c57504da1 ("netfilter: conntrack: Introduce udp offload timeout configuration") Signed-off-by: Volodymyr Mytnyk <volodymyr.mytnyk@plvision.eu> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 626873c446f7559d5af8b48cefad903ffd85cf4e ]

`nf_flowtable_udp_timeout` sysctl option is available only
if CONFIG_NFT_FLOW_OFFLOAD enabled. But infra for this flow
offload UDP timeout was added under CONFIG_NF_FLOW_TABLE
config option. So, if you have CONFIG_NFT_FLOW_OFFLOAD
disabled and CONFIG_NF_FLOW_TABLE enabled, the
`nf_flowtable_udp_timeout` is not present in sysfs.
Please note, that TCP flow offload timeout sysctl option
is present even CONFIG_NFT_FLOW_OFFLOAD is disabled.

I suppose it was a typo in commit that adds UDP flow offload
timeout and CONFIG_NF_FLOW_TABLE should be used instead.

Fixes: 975c57504da1 ("netfilter: conntrack: Introduce udp offload timeout configuration")
Signed-off-by: Volodymyr Mytnyk <volodymyr.mytnyk@plvision.eu>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
netfilter: nf_conntrack_tcp: re-init for syn packets only 2022-05-09T07:16:25+00:00 Florian Westphal fw@strlen.de 2022-04-25T09:47:11+00:00 a5929bc81877b3705c91e6a5fc5f9fc2d7776626 [ Upstream commit c7aab4f17021b636a0ee75bcf28e06fb7c94ab48 ] Jaco Kroon reported tcp problems that Eric Dumazet and Neal Cardwell pinpointed to nf_conntrack tcp_in_window() bug. tcp trace shows following sequence: I > R Flags [S], seq 3451342529, win 62580, options [.. tfo [|tcp]> R > I Flags [S.], seq 2699962254, ack 3451342530, win 65535, options [..] R > I Flags [P.], seq 1:89, ack 1, [..] Note 3rd ACK is from responder to initiator so following branch is taken: } else if (((state->state == TCP_CONNTRACK_SYN_SENT && dir == IP_CT_DIR_ORIGINAL) || (state->state == TCP_CONNTRACK_SYN_RECV && dir == IP_CT_DIR_REPLY)) && after(end, sender->td_end)) { ... because state == TCP_CONNTRACK_SYN_RECV and dir is REPLY. This causes the scaling factor to be reset to 0: window scale option is only present in syn(ack) packets. This in turn makes nf_conntrack mark valid packets as out-of-window. This was always broken, it exists even in original commit where window tracking was added to ip_conntrack (nf_conntrack predecessor) in 2.6.9-rc1 kernel. Restrict to 'tcph->syn', just like the 3rd condtional added in commit 82b72cb94666 ("netfilter: conntrack: re-init state for retransmitted syn-ack"). Upon closer look, those conditionals/branches can be merged: Because earlier checks prevent syn-ack from showing up in original direction, the 'dir' checks in the conditional quoted above are redundant, remove them. Return early for pure syn retransmitted in reply direction (simultaneous open). Fixes: 9fb9cbb1082d ("[NETFILTER]: Add nf_conntrack subsystem.") Reported-by: Jaco Kroon <jaco@uls.co.za> Signed-off-by: Florian Westphal <fw@strlen.de> Acked-by: Jozsef Kadlecsik <kadlec@netfilter.org> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit c7aab4f17021b636a0ee75bcf28e06fb7c94ab48 ]

Jaco Kroon reported tcp problems that Eric Dumazet and Neal Cardwell
pinpointed to nf_conntrack tcp_in_window() bug.

tcp trace shows following sequence:

I > R Flags [S], seq 3451342529, win 62580, options [.. tfo [|tcp]>
R > I Flags [S.], seq 2699962254, ack 3451342530, win 65535, options [..]
R > I Flags [P.], seq 1:89, ack 1, [..]

Note 3rd ACK is from responder to initiator so following branch is taken:
    } else if (((state->state == TCP_CONNTRACK_SYN_SENT
               && dir == IP_CT_DIR_ORIGINAL)
               || (state->state == TCP_CONNTRACK_SYN_RECV
               && dir == IP_CT_DIR_REPLY))
               && after(end, sender->td_end)) {

... because state == TCP_CONNTRACK_SYN_RECV and dir is REPLY.
This causes the scaling factor to be reset to 0: window scale option
is only present in syn(ack) packets.  This in turn makes nf_conntrack
mark valid packets as out-of-window.

This was always broken, it exists even in original commit where
window tracking was added to ip_conntrack (nf_conntrack predecessor)
in 2.6.9-rc1 kernel.

Restrict to 'tcph->syn', just like the 3rd condtional added in
commit 82b72cb94666 ("netfilter: conntrack: re-init state for retransmitted syn-ack").

Upon closer look, those conditionals/branches can be merged:

Because earlier checks prevent syn-ack from showing up in
original direction, the 'dir' checks in the conditional quoted above are
redundant, remove them. Return early for pure syn retransmitted in reply
direction (simultaneous open).

Fixes: 9fb9cbb1082d ("[NETFILTER]: Add nf_conntrack subsystem.")
Reported-by: Jaco Kroon <jaco@uls.co.za>
Signed-off-by: Florian Westphal <fw@strlen.de>
Acked-by: Jozsef Kadlecsik <kadlec@netfilter.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Bluetooth: hci_event: Fix checking for invalid handle on error status 2022-05-09T07:16:24+00:00 Luiz Augusto von Dentz luiz.von.dentz@intel.com 2022-04-22T19:58:16+00:00 a236fa3b5a6324659cb21f249a7227088ef460d9 [ Upstream commit c86cc5a3ec70f5644f1fa21610b943d0441bc1f7 ] Commit d5ebaa7c5f6f6 introduces checks for handle range (e.g HCI_CONN_HANDLE_MAX) but controllers like Intel AX200 don't seem to respect the valid range int case of error status: > HCI Event: Connect Complete (0x03) plen 11 Status: Page Timeout (0x04) Handle: 65535 Address: 94:DB:56:XX:XX:XX (Sony Home Entertainment& Sound Products Inc) Link type: ACL (0x01) Encryption: Disabled (0x00) [1644965.827560] Bluetooth: hci0: Ignoring HCI_Connection_Complete for invalid handle Because of it is impossible to cleanup the connections properly since the stack would attempt to cancel the connection which is no longer in progress causing the following trace: < HCI Command: Create Connection Cancel (0x01|0x0008) plen 6 Address: 94:DB:56:XX:XX:XX (Sony Home Entertainment& Sound Products Inc) = bluetoothd: src/profile.c:record_cb() Unable to get Hands-Free Voice gateway SDP record: Connection timed out > HCI Event: Command Complete (0x0e) plen 10 Create Connection Cancel (0x01|0x0008) ncmd 1 Status: Unknown Connection Identifier (0x02) Address: 94:DB:56:XX:XX:XX (Sony Home Entertainment& Sound Products Inc) < HCI Command: Create Connection Cancel (0x01|0x0008) plen 6 Address: 94:DB:56:XX:XX:XX (Sony Home Entertainment& Sound Products Inc) Fixes: d5ebaa7c5f6f6 ("Bluetooth: hci_event: Ignore multiple conn complete events") Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com> Signed-off-by: Marcel Holtmann <marcel@holtmann.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit c86cc5a3ec70f5644f1fa21610b943d0441bc1f7 ]

Commit d5ebaa7c5f6f6 introduces checks for handle range
(e.g HCI_CONN_HANDLE_MAX) but controllers like Intel AX200 don't seem
to respect the valid range int case of error status:

> HCI Event: Connect Complete (0x03) plen 11
        Status: Page Timeout (0x04)
        Handle: 65535
        Address: 94:DB:56:XX:XX:XX (Sony Home Entertainment&
	Sound Products Inc)
        Link type: ACL (0x01)
        Encryption: Disabled (0x00)
[1644965.827560] Bluetooth: hci0: Ignoring HCI_Connection_Complete for invalid handle

Because of it is impossible to cleanup the connections properly since
the stack would attempt to cancel the connection which is no longer in
progress causing the following trace:

< HCI Command: Create Connection Cancel (0x01|0x0008) plen 6
        Address: 94:DB:56:XX:XX:XX (Sony Home Entertainment&
	Sound Products Inc)
= bluetoothd: src/profile.c:record_cb() Unable to get Hands-Free Voice
	gateway SDP record: Connection timed out
> HCI Event: Command Complete (0x0e) plen 10
      Create Connection Cancel (0x01|0x0008) ncmd 1
        Status: Unknown Connection Identifier (0x02)
        Address: 94:DB:56:XX:XX:XX (Sony Home Entertainment&
	Sound Products Inc)
< HCI Command: Create Connection Cancel (0x01|0x0008) plen 6
        Address: 94:DB:56:XX:XX:XX (Sony Home Entertainment&
	Sound Products Inc)

Fixes: d5ebaa7c5f6f6 ("Bluetooth: hci_event: Ignore multiple conn complete events")
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
mctp: defer the kfree of object mdev->addrs 2022-05-09T07:16:24+00:00 Lin Ma linma@zju.edu.cn 2022-04-22T11:43:40+00:00 019e80a7f71e8e62efda501081172dc70b5a635a [ Upstream commit b561275d633bcd8e0e8055ab86f1a13df75a0269 ] The function mctp_unregister() reclaims the device's relevant resource when a netcard detaches. However, a running routine may be unaware of this and cause the use-after-free of the mdev->addrs object. The race condition can be demonstrated below cleanup thread another thread | unregister_netdev() | mctp_sendmsg() ... | ... mctp_unregister() | rt = mctp_route_lookup() ... | mctl_local_output() kfree(mdev->addrs) | ... | saddr = rt->dev->addrs[0]; | An attacker can adopt the (recent provided) mtcpserial driver with pty to fake the device detaching and use the userfaultfd to increase the race success chance (in mctp_sendmsg). The KASan report for such a POC is shown below: [ 86.051955] ================================================================== [ 86.051955] BUG: KASAN: use-after-free in mctp_local_output+0x4e9/0xb7d [ 86.051955] Read of size 1 at addr ffff888005f298c0 by task poc/295 [ 86.051955] [ 86.051955] Call Trace: [ 86.051955] <TASK> [ 86.051955] dump_stack_lvl+0x33/0x42 [ 86.051955] print_report.cold.13+0xb2/0x6b3 [ 86.051955] ? preempt_schedule_irq+0x57/0x80 [ 86.051955] ? mctp_local_output+0x4e9/0xb7d [ 86.051955] kasan_report+0xa5/0x120 [ 86.051955] ? mctp_local_output+0x4e9/0xb7d [ 86.051955] mctp_local_output+0x4e9/0xb7d [ 86.051955] ? mctp_dev_set_key+0x79/0x79 [ 86.051955] ? copyin+0x38/0x50 [ 86.051955] ? _copy_from_iter+0x1b6/0xf20 [ 86.051955] ? sysvec_apic_timer_interrupt+0x97/0xb0 [ 86.051955] ? asm_sysvec_apic_timer_interrupt+0x12/0x20 [ 86.051955] ? mctp_local_output+0x1/0xb7d [ 86.051955] mctp_sendmsg+0x64d/0xdb0 [ 86.051955] ? mctp_sk_close+0x20/0x20 [ 86.051955] ? __fget_light+0x2fd/0x4f0 [ 86.051955] ? mctp_sk_close+0x20/0x20 [ 86.051955] sock_sendmsg+0xdd/0x110 [ 86.051955] __sys_sendto+0x1cc/0x2a0 [ 86.051955] ? __ia32_sys_getpeername+0xa0/0xa0 [ 86.051955] ? new_sync_write+0x335/0x550 [ 86.051955] ? alloc_file+0x22f/0x500 [ 86.051955] ? __ip_do_redirect+0x820/0x1820 [ 86.051955] ? vfs_write+0x44d/0x7b0 [ 86.051955] ? vfs_write+0x44d/0x7b0 [ 86.051955] ? fput_many+0x15/0x120 [ 86.051955] ? ksys_write+0x155/0x1b0 [ 86.051955] ? __ia32_sys_read+0xa0/0xa0 [ 86.051955] __x64_sys_sendto+0xd8/0x1b0 [ 86.051955] ? exit_to_user_mode_prepare+0x2f/0x120 [ 86.051955] ? syscall_exit_to_user_mode+0x12/0x20 [ 86.051955] do_syscall_64+0x3a/0x80 [ 86.051955] entry_SYSCALL_64_after_hwframe+0x44/0xae [ 86.051955] RIP: 0033:0x7f82118a56b3 [ 86.051955] RSP: 002b:00007ffdb154b110 EFLAGS: 00000293 ORIG_RAX: 000000000000002c [ 86.051955] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f82118a56b3 [ 86.051955] RDX: 0000000000000010 RSI: 00007f8211cd4000 RDI: 0000000000000007 [ 86.051955] RBP: 00007ffdb154c1d0 R08: 00007ffdb154b164 R09: 000000000000000c [ 86.051955] R10: 0000000000000000 R11: 0000000000000293 R12: 000055d779800db0 [ 86.051955] R13: 00007ffdb154c2b0 R14: 0000000000000000 R15: 0000000000000000 [ 86.051955] </TASK> [ 86.051955] [ 86.051955] Allocated by task 295: [ 86.051955] kasan_save_stack+0x1c/0x40 [ 86.051955] __kasan_kmalloc+0x84/0xa0 [ 86.051955] mctp_rtm_newaddr+0x242/0x610 [ 86.051955] rtnetlink_rcv_msg+0x2fd/0x8b0 [ 86.051955] netlink_rcv_skb+0x11c/0x340 [ 86.051955] netlink_unicast+0x439/0x630 [ 86.051955] netlink_sendmsg+0x752/0xc00 [ 86.051955] sock_sendmsg+0xdd/0x110 [ 86.051955] __sys_sendto+0x1cc/0x2a0 [ 86.051955] __x64_sys_sendto+0xd8/0x1b0 [ 86.051955] do_syscall_64+0x3a/0x80 [ 86.051955] entry_SYSCALL_64_after_hwframe+0x44/0xae [ 86.051955] [ 86.051955] Freed by task 301: [ 86.051955] kasan_save_stack+0x1c/0x40 [ 86.051955] kasan_set_track+0x21/0x30 [ 86.051955] kasan_set_free_info+0x20/0x30 [ 86.051955] __kasan_slab_free+0x104/0x170 [ 86.051955] kfree+0x8c/0x290 [ 86.051955] mctp_dev_notify+0x161/0x2c0 [ 86.051955] raw_notifier_call_chain+0x8b/0xc0 [ 86.051955] unregister_netdevice_many+0x299/0x1180 [ 86.051955] unregister_netdevice_queue+0x210/0x2f0 [ 86.051955] unregister_netdev+0x13/0x20 [ 86.051955] mctp_serial_close+0x6d/0xa0 [ 86.051955] tty_ldisc_kill+0x31/0xa0 [ 86.051955] tty_ldisc_hangup+0x24f/0x560 [ 86.051955] __tty_hangup.part.28+0x2ce/0x6b0 [ 86.051955] tty_release+0x327/0xc70 [ 86.051955] __fput+0x1df/0x8b0 [ 86.051955] task_work_run+0xca/0x150 [ 86.051955] exit_to_user_mode_prepare+0x114/0x120 [ 86.051955] syscall_exit_to_user_mode+0x12/0x20 [ 86.051955] do_syscall_64+0x46/0x80 [ 86.051955] entry_SYSCALL_64_after_hwframe+0x44/0xae [ 86.051955] [ 86.051955] The buggy address belongs to the object at ffff888005f298c0 [ 86.051955] which belongs to the cache kmalloc-8 of size 8 [ 86.051955] The buggy address is located 0 bytes inside of [ 86.051955] 8-byte region [ffff888005f298c0, ffff888005f298c8) [ 86.051955] [ 86.051955] The buggy address belongs to the physical page: [ 86.051955] flags: 0x100000000000200(slab|node=0|zone=1) [ 86.051955] raw: 0100000000000200 dead000000000100 dead000000000122 ffff888005c42280 [ 86.051955] raw: 0000000000000000 0000000080660066 00000001ffffffff 0000000000000000 [ 86.051955] page dumped because: kasan: bad access detected [ 86.051955] [ 86.051955] Memory state around the buggy address: [ 86.051955] ffff888005f29780: 00 fc fc fc fc 00 fc fc fc fc 00 fc fc fc fc 00 [ 86.051955] ffff888005f29800: fc fc fc fc 00 fc fc fc fc 00 fc fc fc fc 00 fc [ 86.051955] >ffff888005f29880: fc fc fc fb fc fc fc fc fa fc fc fc fc fa fc fc [ 86.051955] ^ [ 86.051955] ffff888005f29900: fc fc 00 fc fc fc fc 00 fc fc fc fc 00 fc fc fc [ 86.051955] ffff888005f29980: fc 00 fc fc fc fc 00 fc fc fc fc 00 fc fc fc fc [ 86.051955] ================================================================== To this end, just like the commit e04480920d1e ("Bluetooth: defer cleanup of resources in hci_unregister_dev()") this patch defers the destructive kfree(mdev->addrs) in mctp_unregister to the mctp_dev_put, where the refcount of mdev is zero and the entire device is reclaimed. This prevents the use-after-free because the sendmsg thread holds the reference of mdev in the mctp_route object. Fixes: 583be982d934 (mctp: Add device handling and netlink interface) Signed-off-by: Lin Ma <linma@zju.edu.cn> Acked-by: Jeremy Kerr <jk@codeconstruct.com.au> Link: https://lore.kernel.org/r/20220422114340.32346-1-linma@zju.edu.cn Signed-off-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit b561275d633bcd8e0e8055ab86f1a13df75a0269 ]

The function mctp_unregister() reclaims the device's relevant resource
when a netcard detaches. However, a running routine may be unaware of
this and cause the use-after-free of the mdev->addrs object.

The race condition can be demonstrated below

 cleanup thread               another thread
                          |
unregister_netdev()       |  mctp_sendmsg()
...                       |    ...
  mctp_unregister()       |    rt = mctp_route_lookup()
    ...                   |    mctl_local_output()
    kfree(mdev->addrs)    |      ...
                          |      saddr = rt->dev->addrs[0];
                          |

An attacker can adopt the (recent provided) mtcpserial driver with pty
to fake the device detaching and use the userfaultfd to increase the
race success chance (in mctp_sendmsg). The KASan report for such a POC
is shown below:

[   86.051955] ==================================================================
[   86.051955] BUG: KASAN: use-after-free in mctp_local_output+0x4e9/0xb7d
[   86.051955] Read of size 1 at addr ffff888005f298c0 by task poc/295
[   86.051955]
[   86.051955] Call Trace:
[   86.051955]  <TASK>
[   86.051955]  dump_stack_lvl+0x33/0x42
[   86.051955]  print_report.cold.13+0xb2/0x6b3
[   86.051955]  ? preempt_schedule_irq+0x57/0x80
[   86.051955]  ? mctp_local_output+0x4e9/0xb7d
[   86.051955]  kasan_report+0xa5/0x120
[   86.051955]  ? mctp_local_output+0x4e9/0xb7d
[   86.051955]  mctp_local_output+0x4e9/0xb7d
[   86.051955]  ? mctp_dev_set_key+0x79/0x79
[   86.051955]  ? copyin+0x38/0x50
[   86.051955]  ? _copy_from_iter+0x1b6/0xf20
[   86.051955]  ? sysvec_apic_timer_interrupt+0x97/0xb0
[   86.051955]  ? asm_sysvec_apic_timer_interrupt+0x12/0x20
[   86.051955]  ? mctp_local_output+0x1/0xb7d
[   86.051955]  mctp_sendmsg+0x64d/0xdb0
[   86.051955]  ? mctp_sk_close+0x20/0x20
[   86.051955]  ? __fget_light+0x2fd/0x4f0
[   86.051955]  ? mctp_sk_close+0x20/0x20
[   86.051955]  sock_sendmsg+0xdd/0x110
[   86.051955]  __sys_sendto+0x1cc/0x2a0
[   86.051955]  ? __ia32_sys_getpeername+0xa0/0xa0
[   86.051955]  ? new_sync_write+0x335/0x550
[   86.051955]  ? alloc_file+0x22f/0x500
[   86.051955]  ? __ip_do_redirect+0x820/0x1820
[   86.051955]  ? vfs_write+0x44d/0x7b0
[   86.051955]  ? vfs_write+0x44d/0x7b0
[   86.051955]  ? fput_many+0x15/0x120
[   86.051955]  ? ksys_write+0x155/0x1b0
[   86.051955]  ? __ia32_sys_read+0xa0/0xa0
[   86.051955]  __x64_sys_sendto+0xd8/0x1b0
[   86.051955]  ? exit_to_user_mode_prepare+0x2f/0x120
[   86.051955]  ? syscall_exit_to_user_mode+0x12/0x20
[   86.051955]  do_syscall_64+0x3a/0x80
[   86.051955]  entry_SYSCALL_64_after_hwframe+0x44/0xae
[   86.051955] RIP: 0033:0x7f82118a56b3
[   86.051955] RSP: 002b:00007ffdb154b110 EFLAGS: 00000293 ORIG_RAX: 000000000000002c
[   86.051955] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f82118a56b3
[   86.051955] RDX: 0000000000000010 RSI: 00007f8211cd4000 RDI: 0000000000000007
[   86.051955] RBP: 00007ffdb154c1d0 R08: 00007ffdb154b164 R09: 000000000000000c
[   86.051955] R10: 0000000000000000 R11: 0000000000000293 R12: 000055d779800db0
[   86.051955] R13: 00007ffdb154c2b0 R14: 0000000000000000 R15: 0000000000000000
[   86.051955]  </TASK>
[   86.051955]
[   86.051955] Allocated by task 295:
[   86.051955]  kasan_save_stack+0x1c/0x40
[   86.051955]  __kasan_kmalloc+0x84/0xa0
[   86.051955]  mctp_rtm_newaddr+0x242/0x610
[   86.051955]  rtnetlink_rcv_msg+0x2fd/0x8b0
[   86.051955]  netlink_rcv_skb+0x11c/0x340
[   86.051955]  netlink_unicast+0x439/0x630
[   86.051955]  netlink_sendmsg+0x752/0xc00
[   86.051955]  sock_sendmsg+0xdd/0x110
[   86.051955]  __sys_sendto+0x1cc/0x2a0
[   86.051955]  __x64_sys_sendto+0xd8/0x1b0
[   86.051955]  do_syscall_64+0x3a/0x80
[   86.051955]  entry_SYSCALL_64_after_hwframe+0x44/0xae
[   86.051955]
[   86.051955] Freed by task 301:
[   86.051955]  kasan_save_stack+0x1c/0x40
[   86.051955]  kasan_set_track+0x21/0x30
[   86.051955]  kasan_set_free_info+0x20/0x30
[   86.051955]  __kasan_slab_free+0x104/0x170
[   86.051955]  kfree+0x8c/0x290
[   86.051955]  mctp_dev_notify+0x161/0x2c0
[   86.051955]  raw_notifier_call_chain+0x8b/0xc0
[   86.051955]  unregister_netdevice_many+0x299/0x1180
[   86.051955]  unregister_netdevice_queue+0x210/0x2f0
[   86.051955]  unregister_netdev+0x13/0x20
[   86.051955]  mctp_serial_close+0x6d/0xa0
[   86.051955]  tty_ldisc_kill+0x31/0xa0
[   86.051955]  tty_ldisc_hangup+0x24f/0x560
[   86.051955]  __tty_hangup.part.28+0x2ce/0x6b0
[   86.051955]  tty_release+0x327/0xc70
[   86.051955]  __fput+0x1df/0x8b0
[   86.051955]  task_work_run+0xca/0x150
[   86.051955]  exit_to_user_mode_prepare+0x114/0x120
[   86.051955]  syscall_exit_to_user_mode+0x12/0x20
[   86.051955]  do_syscall_64+0x46/0x80
[   86.051955]  entry_SYSCALL_64_after_hwframe+0x44/0xae
[   86.051955]
[   86.051955] The buggy address belongs to the object at ffff888005f298c0
[   86.051955]  which belongs to the cache kmalloc-8 of size 8
[   86.051955] The buggy address is located 0 bytes inside of
[   86.051955]  8-byte region [ffff888005f298c0, ffff888005f298c8)
[   86.051955]
[   86.051955] The buggy address belongs to the physical page:
[   86.051955] flags: 0x100000000000200(slab|node=0|zone=1)
[   86.051955] raw: 0100000000000200 dead000000000100 dead000000000122 ffff888005c42280
[   86.051955] raw: 0000000000000000 0000000080660066 00000001ffffffff 0000000000000000
[   86.051955] page dumped because: kasan: bad access detected
[   86.051955]
[   86.051955] Memory state around the buggy address:
[   86.051955]  ffff888005f29780: 00 fc fc fc fc 00 fc fc fc fc 00 fc fc fc fc 00
[   86.051955]  ffff888005f29800: fc fc fc fc 00 fc fc fc fc 00 fc fc fc fc 00 fc
[   86.051955] >ffff888005f29880: fc fc fc fb fc fc fc fc fa fc fc fc fc fa fc fc
[   86.051955]                                            ^
[   86.051955]  ffff888005f29900: fc fc 00 fc fc fc fc 00 fc fc fc fc 00 fc fc fc
[   86.051955]  ffff888005f29980: fc 00 fc fc fc fc 00 fc fc fc fc 00 fc fc fc fc
[   86.051955] ==================================================================

To this end, just like the commit e04480920d1e ("Bluetooth: defer
cleanup of resources in hci_unregister_dev()")  this patch defers the
destructive kfree(mdev->addrs) in mctp_unregister to the mctp_dev_put,
where the refcount of mdev is zero and the entire device is reclaimed.
This prevents the use-after-free because the sendmsg thread holds the
reference of mdev in the mctp_route object.

Fixes: 583be982d934 (mctp: Add device handling and netlink interface)
Signed-off-by: Lin Ma <linma@zju.edu.cn>
Acked-by: Jeremy Kerr <jk@codeconstruct.com.au>
Link: https://lore.kernel.org/r/20220422114340.32346-1-linma@zju.edu.cn
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
tcp: make sure treq->af_specific is initialized 2022-05-09T07:16:23+00:00 Eric Dumazet edumazet@google.com 2022-04-24T20:35:09+00:00 0dc770455611c56990e841f99be2d79446636c57 [ Upstream commit ba5a4fdd63ae0c575707030db0b634b160baddd7 ] syzbot complained about a recent change in TCP stack, hitting a NULL pointer [1] tcp request sockets have an af_specific pointer, which was used before the blamed change only for SYNACK generation in non SYNCOOKIE mode. tcp requests sockets momentarily created when third packet coming from client in SYNCOOKIE mode were not using treq->af_specific. Make sure this field is populated, in the same way normal TCP requests sockets do in tcp_conn_request(). [1] TCP: request_sock_TCPv6: Possible SYN flooding on port 20002. Sending cookies. Check SNMP counters. general protection fault, probably for non-canonical address 0xdffffc0000000001: 0000 [#1] PREEMPT SMP KASAN KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f] CPU: 1 PID: 3695 Comm: syz-executor864 Not tainted 5.18.0-rc3-syzkaller-00224-g5fd1fe4807f9 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:tcp_create_openreq_child+0xe16/0x16b0 net/ipv4/tcp_minisocks.c:534 Code: 48 c1 ea 03 80 3c 02 00 0f 85 e5 07 00 00 4c 8b b3 28 01 00 00 48 b8 00 00 00 00 00 fc ff df 49 8d 7e 08 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 c9 07 00 00 48 8b 3c 24 48 89 de 41 ff 56 08 48 RSP: 0018:ffffc90000de0588 EFLAGS: 00010202 RAX: dffffc0000000000 RBX: ffff888076490330 RCX: 0000000000000100 RDX: 0000000000000001 RSI: ffffffff87d67ff0 RDI: 0000000000000008 RBP: ffff88806ee1c7f8 R08: 0000000000000000 R09: 0000000000000000 R10: ffffffff87d67f00 R11: 0000000000000000 R12: ffff88806ee1bfc0 R13: ffff88801b0e0368 R14: 0000000000000000 R15: 0000000000000000 FS: 00007f517fe58700(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffcead76960 CR3: 000000006f97b000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <IRQ> tcp_v6_syn_recv_sock+0x199/0x23b0 net/ipv6/tcp_ipv6.c:1267 tcp_get_cookie_sock+0xc9/0x850 net/ipv4/syncookies.c:207 cookie_v6_check+0x15c3/0x2340 net/ipv6/syncookies.c:258 tcp_v6_cookie_check net/ipv6/tcp_ipv6.c:1131 [inline] tcp_v6_do_rcv+0x1148/0x13b0 net/ipv6/tcp_ipv6.c:1486 tcp_v6_rcv+0x3305/0x3840 net/ipv6/tcp_ipv6.c:1725 ip6_protocol_deliver_rcu+0x2e9/0x1900 net/ipv6/ip6_input.c:422 ip6_input_finish+0x14c/0x2c0 net/ipv6/ip6_input.c:464 NF_HOOK include/linux/netfilter.h:307 [inline] NF_HOOK include/linux/netfilter.h:301 [inline] ip6_input+0x9c/0xd0 net/ipv6/ip6_input.c:473 dst_input include/net/dst.h:461 [inline] ip6_rcv_finish net/ipv6/ip6_input.c:76 [inline] NF_HOOK include/linux/netfilter.h:307 [inline] NF_HOOK include/linux/netfilter.h:301 [inline] ipv6_rcv+0x27f/0x3b0 net/ipv6/ip6_input.c:297 __netif_receive_skb_one_core+0x114/0x180 net/core/dev.c:5405 __netif_receive_skb+0x24/0x1b0 net/core/dev.c:5519 process_backlog+0x3a0/0x7c0 net/core/dev.c:5847 __napi_poll+0xb3/0x6e0 net/core/dev.c:6413 napi_poll net/core/dev.c:6480 [inline] net_rx_action+0x8ec/0xc60 net/core/dev.c:6567 __do_softirq+0x29b/0x9c2 kernel/softirq.c:558 invoke_softirq kernel/softirq.c:432 [inline] __irq_exit_rcu+0x123/0x180 kernel/softirq.c:637 irq_exit_rcu+0x5/0x20 kernel/softirq.c:649 sysvec_apic_timer_interrupt+0x93/0xc0 arch/x86/kernel/apic/apic.c:1097 Fixes: 5b0b9e4c2c89 ("tcp: md5: incorrect tcp_header_len for incoming connections") Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Francesco Ruggeri <fruggeri@arista.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit ba5a4fdd63ae0c575707030db0b634b160baddd7 ]

syzbot complained about a recent change in TCP stack,
hitting a NULL pointer [1]

tcp request sockets have an af_specific pointer, which
was used before the blamed change only for SYNACK generation
in non SYNCOOKIE mode.

tcp requests sockets momentarily created when third packet
coming from client in SYNCOOKIE mode were not using
treq->af_specific.

Make sure this field is populated, in the same way normal
TCP requests sockets do in tcp_conn_request().

[1]
TCP: request_sock_TCPv6: Possible SYN flooding on port 20002. Sending cookies.  Check SNMP counters.
general protection fault, probably for non-canonical address 0xdffffc0000000001: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f]
CPU: 1 PID: 3695 Comm: syz-executor864 Not tainted 5.18.0-rc3-syzkaller-00224-g5fd1fe4807f9 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:tcp_create_openreq_child+0xe16/0x16b0 net/ipv4/tcp_minisocks.c:534
Code: 48 c1 ea 03 80 3c 02 00 0f 85 e5 07 00 00 4c 8b b3 28 01 00 00 48 b8 00 00 00 00 00 fc ff df 49 8d 7e 08 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 c9 07 00 00 48 8b 3c 24 48 89 de 41 ff 56 08 48
RSP: 0018:ffffc90000de0588 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: ffff888076490330 RCX: 0000000000000100
RDX: 0000000000000001 RSI: ffffffff87d67ff0 RDI: 0000000000000008
RBP: ffff88806ee1c7f8 R08: 0000000000000000 R09: 0000000000000000
R10: ffffffff87d67f00 R11: 0000000000000000 R12: ffff88806ee1bfc0
R13: ffff88801b0e0368 R14: 0000000000000000 R15: 0000000000000000
FS:  00007f517fe58700(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffcead76960 CR3: 000000006f97b000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 tcp_v6_syn_recv_sock+0x199/0x23b0 net/ipv6/tcp_ipv6.c:1267
 tcp_get_cookie_sock+0xc9/0x850 net/ipv4/syncookies.c:207
 cookie_v6_check+0x15c3/0x2340 net/ipv6/syncookies.c:258
 tcp_v6_cookie_check net/ipv6/tcp_ipv6.c:1131 [inline]
 tcp_v6_do_rcv+0x1148/0x13b0 net/ipv6/tcp_ipv6.c:1486
 tcp_v6_rcv+0x3305/0x3840 net/ipv6/tcp_ipv6.c:1725
 ip6_protocol_deliver_rcu+0x2e9/0x1900 net/ipv6/ip6_input.c:422
 ip6_input_finish+0x14c/0x2c0 net/ipv6/ip6_input.c:464
 NF_HOOK include/linux/netfilter.h:307 [inline]
 NF_HOOK include/linux/netfilter.h:301 [inline]
 ip6_input+0x9c/0xd0 net/ipv6/ip6_input.c:473
 dst_input include/net/dst.h:461 [inline]
 ip6_rcv_finish net/ipv6/ip6_input.c:76 [inline]
 NF_HOOK include/linux/netfilter.h:307 [inline]
 NF_HOOK include/linux/netfilter.h:301 [inline]
 ipv6_rcv+0x27f/0x3b0 net/ipv6/ip6_input.c:297
 __netif_receive_skb_one_core+0x114/0x180 net/core/dev.c:5405
 __netif_receive_skb+0x24/0x1b0 net/core/dev.c:5519
 process_backlog+0x3a0/0x7c0 net/core/dev.c:5847
 __napi_poll+0xb3/0x6e0 net/core/dev.c:6413
 napi_poll net/core/dev.c:6480 [inline]
 net_rx_action+0x8ec/0xc60 net/core/dev.c:6567
 __do_softirq+0x29b/0x9c2 kernel/softirq.c:558
 invoke_softirq kernel/softirq.c:432 [inline]
 __irq_exit_rcu+0x123/0x180 kernel/softirq.c:637
 irq_exit_rcu+0x5/0x20 kernel/softirq.c:649
 sysvec_apic_timer_interrupt+0x93/0xc0 arch/x86/kernel/apic/apic.c:1097

Fixes: 5b0b9e4c2c89 ("tcp: md5: incorrect tcp_header_len for incoming connections")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Francesco Ruggeri <fruggeri@arista.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
tcp: fix potential xmit stalls caused by TCP_NOTSENT_LOWAT 2022-05-09T07:16:23+00:00 Eric Dumazet edumazet@google.com 2022-04-25T00:34:07+00:00 0373f2fb5baeae10b17a9473f781541b26b86386 [ Upstream commit 4bfe744ff1644fbc0a991a2677dc874475dd6776 ] I had this bug sitting for too long in my pile, it is time to fix it. Thanks to Doug Porter for reminding me of it! We had various attempts in the past, including commit 0cbe6a8f089e ("tcp: remove SOCK_QUEUE_SHRUNK"), but the issue is that TCP stack currently only generates EPOLLOUT from input path, when tp->snd_una has advanced and skb(s) cleaned from rtx queue. If a flow has a big RTT, and/or receives SACKs, it is possible that the notsent part (tp->write_seq - tp->snd_nxt) reaches 0 and no more data can be sent until tp->snd_una finally advances. What is needed is to also check if POLLOUT needs to be generated whenever tp->snd_nxt is advanced, from output path. This bug triggers more often after an idle period, as we do not receive ACK for at least one RTT. tcp_notsent_lowat could be a fraction of what CWND and pacing rate would allow to send during this RTT. In a followup patch, I will remove the bogus call to tcp_chrono_stop(sk, TCP_CHRONO_SNDBUF_LIMITED) from tcp_check_space(). Fact that we have decided to generate an EPOLLOUT does not mean the application has immediately refilled the transmit queue. This optimistic call might have been the reason the bug seemed not too serious. Tested: 200 ms rtt, 1% packet loss, 32 MB tcp_rmem[2] and tcp_wmem[2] $ echo 500000 >/proc/sys/net/ipv4/tcp_notsent_lowat $ cat bench_rr.sh SUM=0 for i in {1..10} do V=`netperf -H remote_host -l30 -t TCP_RR -- -r 10000000,10000 -o LOCAL_BYTES_SENT | egrep -v "MIGRATED|Bytes"` echo $V SUM=$(($SUM + $V)) done echo SUM=$SUM Before patch: $ bench_rr.sh 130000000 80000000 140000000 140000000 140000000 140000000 130000000 40000000 90000000 110000000 SUM=1140000000 After patch: $ bench_rr.sh 430000000 590000000 530000000 450000000 450000000 350000000 450000000 490000000 480000000 460000000 SUM=4680000000 # This is 410 % of the value before patch. Fixes: c9bee3b7fdec ("tcp: TCP_NOTSENT_LOWAT socket option") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: Doug Porter <dsp@fb.com> Cc: Soheil Hassas Yeganeh <soheil@google.com> Cc: Neal Cardwell <ncardwell@google.com> Acked-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 4bfe744ff1644fbc0a991a2677dc874475dd6776 ]

I had this bug sitting for too long in my pile, it is time to fix it.

Thanks to Doug Porter for reminding me of it!

We had various attempts in the past, including commit
0cbe6a8f089e ("tcp: remove SOCK_QUEUE_SHRUNK"),
but the issue is that TCP stack currently only generates
EPOLLOUT from input path, when tp->snd_una has advanced
and skb(s) cleaned from rtx queue.

If a flow has a big RTT, and/or receives SACKs, it is possible
that the notsent part (tp->write_seq - tp->snd_nxt) reaches 0
and no more data can be sent until tp->snd_una finally advances.

What is needed is to also check if POLLOUT needs to be generated
whenever tp->snd_nxt is advanced, from output path.

This bug triggers more often after an idle period, as
we do not receive ACK for at least one RTT. tcp_notsent_lowat
could be a fraction of what CWND and pacing rate would allow to
send during this RTT.

In a followup patch, I will remove the bogus call
to tcp_chrono_stop(sk, TCP_CHRONO_SNDBUF_LIMITED)
from tcp_check_space(). Fact that we have decided to generate
an EPOLLOUT does not mean the application has immediately
refilled the transmit queue. This optimistic call
might have been the reason the bug seemed not too serious.

Tested:

200 ms rtt, 1% packet loss, 32 MB tcp_rmem[2] and tcp_wmem[2]

$ echo 500000 >/proc/sys/net/ipv4/tcp_notsent_lowat
$ cat bench_rr.sh
SUM=0
for i in {1..10}
do
 V=`netperf -H remote_host -l30 -t TCP_RR -- -r 10000000,10000 -o LOCAL_BYTES_SENT | egrep -v "MIGRATED|Bytes"`
 echo $V
 SUM=$(($SUM + $V))
done
echo SUM=$SUM

Before patch:
$ bench_rr.sh
130000000
80000000
140000000
140000000
140000000
140000000
130000000
40000000
90000000
110000000
SUM=1140000000

After patch:
$ bench_rr.sh
430000000
590000000
530000000
450000000
450000000
350000000
450000000
490000000
480000000
460000000
SUM=4680000000  # This is 410 % of the value before patch.

Fixes: c9bee3b7fdec ("tcp: TCP_NOTSENT_LOWAT socket option")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Doug Porter <dsp@fb.com>
Cc: Soheil Hassas Yeganeh <soheil@google.com>
Cc: Neal Cardwell <ncardwell@google.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>