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  1. 22 Mar, 2022 3 commits
  3. 21 Mar, 2022 5 commits
    • Jakub Kicinski's avatar
      tcp: ensure PMTU updates are processed during fastopen · ed0c99dc
      Jakub Kicinski authored 
      tp->rx_opt.mss_clamp is not populated, yet, during TFO send so we
rise it to the local MSS. tp->mss_cache is not updated, however:

tcp_v6_connect():
  tp->rx_opt.mss_clamp = IPV6_MIN_MTU - headers;
  tcp_connect():
     tcp_connect_init():
       tp->mss_cache = min(mtu, tp->rx_opt.mss_clamp)
     tcp_send_syn_data():
       tp->rx_opt.mss_clamp = tp->advmss

After recent fixes to ICMPv6 PTB handling we started dropping
PMTU updates higher than tp->mss_cache. Because of the stale
tp->mss_cache value PMTU updates during TFO are always dropped.

Thanks to Wei for helping zero in on the problem and the fix!

Fixes: c7bb4b89 ("ipv6: tcp: drop silly ICMPv6 packet too big messages")
Reported-by: default avatarAndre Nash <alnash@fb.com>
Reported-by: default avatarNeil Spring <ntspring@fb.com>
Reviewed-by: default avatarWei Wang <weiwan@google.com>
Acked-by: default avatarYuchung Cheng <ycheng@google.com>
Acked-by: default avatarMartin KaFai Lau <kafai@fb.com>
Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
Reviewed-by: default avatarEric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/20220321165957.1769954-1-kuba@kernel.orgSigned-off-by: default avatarJakub Kicinski <kuba@kernel.org>
      ed0c99dc
    • Jeremy Linton's avatar
      net: bcmgenet: Use stronger register read/writes to assure ordering · 8d3ea3d4
      Jeremy Linton authored 
      GCC12 appears to be much smarter about its dependency tracking and is
aware that the relaxed variants are just normal loads and stores and
this is causing problems like:

[  210.074549] ------------[ cut here ]------------
[  210.079223] NETDEV WATCHDOG: enabcm6e4ei0 (bcmgenet): transmit queue 1 timed out
[  210.086717] WARNING: CPU: 1 PID: 0 at net/sched/sch_generic.c:529 dev_watchdog+0x234/0x240
[  210.095044] Modules linked in: genet(E) nft_fib_inet nft_fib_ipv4 nft_fib_ipv6 nft_fib nft_reject_inet nf_reject_ipv4 nf_reject_ipv6 nft_reject nft_ct nft_chain_nat]
[  210.146561] ACPI CPPC: PCC check channel failed for ss: 0. ret=-110
[  210.146927] CPU: 1 PID: 0 Comm: swapper/1 Tainted: G            E     5.17.0-rc7G12+ #58
[  210.153226] CPPC Cpufreq:cppc_scale_freq_workfn: failed to read perf counters
[  210.161349] Hardware name: Raspberry Pi Foundation Raspberry Pi 4 Model B/Raspberry Pi 4 Model B, BIOS EDK2-DEV 02/08/2022
[  210.161353] pstate: 80400005 (Nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[  210.161358] pc : dev_watchdog+0x234/0x240
[  210.161364] lr : dev_watchdog+0x234/0x240
[  210.161368] sp : ffff8000080a3a40
[  210.161370] x29: ffff8000080a3a40 x28: ffffcd425af87000 x27: ffff8000080a3b20
[  210.205150] x26: ffffcd425aa00000 x25: 0000000000000001 x24: ffffcd425af8ec08
[  210.212321] x23: 0000000000000100 x22: ffffcd425af87000 x21: ffff55b142688000
[  210.219491] x20: 0000000000000001 x19: ffff55b1426884c8 x18: ffffffffffffffff
[  210.226661] x17: 64656d6974203120 x16: 0000000000000001 x15: 6d736e617274203a
[  210.233831] x14: 2974656e65676d63 x13: ffffcd4259c300d8 x12: ffffcd425b07d5f0
[  210.241001] x11: 00000000ffffffff x10: ffffcd425b07d5f0 x9 : ffffcd4258bdad9c
[  210.248171] x8 : 00000000ffffdfff x7 : 000000000000003f x6 : 0000000000000000
[  210.255341] x5 : 0000000000000000 x4 : 0000000000000000 x3 : 0000000000001000
[  210.262511] x2 : 0000000000001000 x1 : 0000000000000005 x0 : 0000000000000044
[  210.269682] Call trace:
[  210.272133]  dev_watchdog+0x234/0x240
[  210.275811]  call_timer_fn+0x3c/0x15c
[  210.279489]  __run_timers.part.0+0x288/0x310
[  210.283777]  run_timer_softirq+0x48/0x80
[  210.287716]  __do_softirq+0x128/0x360
[  210.291392]  __irq_exit_rcu+0x138/0x140
[  210.295243]  irq_exit_rcu+0x1c/0x30
[  210.298745]  el1_interrupt+0x38/0x54
[  210.302334]  el1h_64_irq_handler+0x18/0x24
[  210.306445]  el1h_64_irq+0x7c/0x80
[  210.309857]  arch_cpu_idle+0x18/0x2c
[  210.313445]  default_idle_call+0x4c/0x140
[  210.317470]  cpuidle_idle_call+0x14c/0x1a0
[  210.321584]  do_idle+0xb0/0x100
[  210.324737]  cpu_startup_entry+0x30/0x8c
[  210.328675]  secondary_start_kernel+0xe4/0x110
[  210.333138]  __secondary_switched+0x94/0x98

The assumption when these were relaxed seems to be that device memory
would be mapped non reordering, and that other constructs
(spinlocks/etc) would provide the barriers to assure that packet data
and in memory rings/queues were ordered with respect to device
register reads/writes. This itself seems a bit sketchy, but the real
problem with GCC12 is that it is moving the actual reads/writes around
at will as though they were independent operations when in truth they
are not, but the compiler can't know that. When looking at the
assembly dumps for many of these routines its possible to see very
clean, but not strictly in program order operations occurring as the
compiler would be free to do if these weren't actually register
reads/write operations.

Its possible to suppress the timeout with a liberal bit of dma_mb()'s
sprinkled around but the device still seems unable to reliably
send/receive data. A better plan is to use the safer readl/writel
everywhere.

Since this partially reverts an older commit, which notes the use of
the relaxed variants for performance reasons. I would suggest that
any performance problems with this commit are targeted at relaxing only
the performance critical code paths after assuring proper barriers.

Fixes: 69d2ea9c ("net: bcmgenet: Use correct I/O accessors")
Reported-by: default avatarPeter Robinson <pbrobinson@gmail.com>
Signed-off-by: default avatarJeremy Linton <jeremy.linton@arm.com>
Acked-by: default avatarPeter Robinson <pbrobinson@gmail.com>
Tested-by: default avatarPeter Robinson <pbrobinson@gmail.com>
Acked-by: default avatarFlorian Fainelli <f.fainelli@gmail.com>
Link: https://lore.kernel.org/r/20220310045358.224350-1-jeremy.linton@arm.comSigned-off-by: default avatarJakub Kicinski <kuba@kernel.org>
      8d3ea3d4
    • David S. Miller's avatar
      Merge branch 'ax25-fixes' · ed32641e
      David S. Miller authored 
      Duoming Zhou says:

====================
Fix refcount leak and NPD bugs in ax25

The first patch fixes refcount leak in ax25 that could cause
ax25-ex-connected-session-now-listening-state-bug.

The second patch fixes NPD bugs in ax25 timers.
====================
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      ed32641e
    • Duoming Zhou's avatar
      ax25: Fix NULL pointer dereferences in ax25 timers · fc6d01ff
      Duoming Zhou authored 
      The previous commit 7ec02f5a ("ax25: fix NPD bug in ax25_disconnect")
move ax25_disconnect into lock_sock() in order to prevent NPD bugs. But
there are race conditions that may lead to null pointer dereferences in
ax25_heartbeat_expiry(), ax25_t1timer_expiry(), ax25_t2timer_expiry(),
ax25_t3timer_expiry() and ax25_idletimer_expiry(), when we use
ax25_kill_by_device() to detach the ax25 device.

One of the race conditions that cause null pointer dereferences can be
shown as below:

      (Thread 1)                    |      (Thread 2)
ax25_connect()                      |
 ax25_std_establish_data_link()     |
  ax25_start_t1timer()              |
   mod_timer(&ax25->t1timer,..)     |
                                    | ax25_kill_by_device()
   (wait a time)                    |  ...
                                    |  s->ax25_dev = NULL; //(1)
   ax25_t1timer_expiry()            |
    ax25->ax25_dev->values[..] //(2)|  ...
     ...                            |

We set null to ax25_cb->ax25_dev in position (1) and dereference
the null pointer in position (2).

The corresponding fail log is shown below:
===============================================================
BUG: kernel NULL pointer dereference, address: 0000000000000050
CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.17.0-rc6-00794-g45690b7d0
RIP: 0010:ax25_t1timer_expiry+0x12/0x40
...
Call Trace:
 call_timer_fn+0x21/0x120
 __run_timers.part.0+0x1ca/0x250
 run_timer_softirq+0x2c/0x60
 __do_softirq+0xef/0x2f3
 irq_exit_rcu+0xb6/0x100
 sysvec_apic_timer_interrupt+0xa2/0xd0
...

This patch moves ax25_disconnect() before s->ax25_dev = NULL
and uses del_timer_sync() to delete timers in ax25_disconnect().
If ax25_disconnect() is called by ax25_kill_by_device() or
ax25->ax25_dev is NULL, the reason in ax25_disconnect() will be
equal to ENETUNREACH, it will wait all timers to stop before we
set null to s->ax25_dev in ax25_kill_by_device().

Fixes: 7ec02f5a ("ax25: fix NPD bug in ax25_disconnect")
Signed-off-by: default avatarDuoming Zhou <duoming@zju.edu.cn>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      fc6d01ff
    • Duoming Zhou's avatar
      ax25: Fix refcount leaks caused by ax25_cb_del() · 9fd75b66
      Duoming Zhou authored 
      The previous commit d01ffb9e ("ax25: add refcount in ax25_dev to
avoid UAF bugs") and commit feef318c ("ax25: fix UAF bugs of
net_device caused by rebinding operation") increase the refcounts of
ax25_dev and net_device in ax25_bind() and decrease the matching refcounts
in ax25_kill_by_device() in order to prevent UAF bugs, but there are
reference count leaks.

The root cause of refcount leaks is shown below:

     (Thread 1)                      |      (Thread 2)
ax25_bind()                          |
 ...                                 |
 ax25_addr_ax25dev()                 |
  ax25_dev_hold()   //(1)            |
  ...                                |
 dev_hold_track()   //(2)            |
 ...                                 | ax25_destroy_socket()
                                     |  ax25_cb_del()
                                     |   ...
                                     |   hlist_del_init() //(3)
                                     |
                                     |
     (Thread 3)                      |
ax25_kill_by_device()                |
 ...                                 |
 ax25_for_each(s, &ax25_list) {      |
  if (s->ax25_dev == ax25_dev) //(4) |
   ...                               |

Firstly, we use ax25_bind() to increase the refcount of ax25_dev in
position (1) and increase the refcount of net_device in position (2).
Then, we use ax25_cb_del() invoked by ax25_destroy_socket() to delete
ax25_cb in hlist in position (3) before calling ax25_kill_by_device().
Finally, the decrements of refcounts in ax25_kill_by_device() will not
be executed, because no s->ax25_dev equals to ax25_dev in position (4).

This patch adds decrements of refcounts in ax25_release() and use
lock_sock() to do synchronization. If refcounts decrease in ax25_release(),
the decrements of refcounts in ax25_kill_by_device() will not be
executed and vice versa.

Fixes: d01ffb9e ("ax25: add refcount in ax25_dev to avoid UAF bugs")
Fixes: 87563a04 ("ax25: fix reference count leaks of ax25_dev")
Fixes: feef318c ("ax25: fix UAF bugs of net_device caused by rebinding operation")
Reported-by: default avatarThomas Osterried <thomas@osterried.de>
Signed-off-by: default avatarDuoming Zhou <duoming@zju.edu.cn>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      9fd75b66
  5. 19 Mar, 2022 1 commit
    • Petr Machata's avatar
      af_netlink: Fix shift out of bounds in group mask calculation · 0caf6d99
      Petr Machata authored 
      When a netlink message is received, netlink_recvmsg() fills in the address
of the sender. One of the fields is the 32-bit bitfield nl_groups, which
carries the multicast group on which the message was received. The least
significant bit corresponds to group 1, and therefore the highest group
that the field can represent is 32. Above that, the UB sanitizer flags the
out-of-bounds shift attempts.

Which bits end up being set in such case is implementation defined, but
it's either going to be a wrong non-zero value, or zero, which is at least
not misleading. Make the latter choice deterministic by always setting to 0
for higher-numbered multicast groups.

To get information about membership in groups >= 32, userspace is expected
to use nl_pktinfo control messages[0], which are enabled by NETLINK_PKTINFO
socket option.
[0] https://lwn.net/Articles/147608/

The way to trigger this issue is e.g. through monitoring the BRVLAN group:

	# bridge monitor vlan &
	# ip link add name br type bridge

Which produces the following citation:

	UBSAN: shift-out-of-bounds in net/netlink/af_netlink.c:162:19
	shift exponent 32 is too large for 32-bit type 'int'

Fixes: f7fa9b10 ("[NETLINK]: Support dynamic number of multicast groups per netlink family")
Signed-off-by: default avatarPetr Machata <petrm@nvidia.com>
Reviewed-by: default avatarIdo Schimmel <idosch@nvidia.com>
Link: https://lore.kernel.org/r/2bef6aabf201d1fc16cca139a744700cff9dcb04.1647527635.git.petrm@nvidia.comSigned-off-by: default avatarJakub Kicinski <kuba@kernel.org>
      0caf6d99
  7. 18 Mar, 2022 10 commits
    • Yonglong Li's avatar
      mptcp: Fix crash due to tcp_tsorted_anchor was initialized before release skb · 3ef3905a
      Yonglong Li authored 
      Got crash when doing pressure test of mptcp:

===========================================================================
dst_release: dst:ffffa06ce6e5c058 refcnt:-1
kernel tried to execute NX-protected page - exploit attempt? (uid: 0)
BUG: unable to handle kernel paging request at ffffa06ce6e5c058
PGD 190a01067 P4D 190a01067 PUD 43fffb067 PMD 22e403063 PTE 8000000226e5c063
Oops: 0011 [#1] SMP PTI
CPU: 7 PID: 7823 Comm: kworker/7:0 Kdump: loaded Tainted: G            E
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.2.1 04/01/2014
Call Trace:
 ? skb_release_head_state+0x68/0x100
 ? skb_release_all+0xe/0x30
 ? kfree_skb+0x32/0xa0
 ? mptcp_sendmsg_frag+0x57e/0x750
 ? __mptcp_retrans+0x21b/0x3c0
 ? __switch_to_asm+0x35/0x70
 ? mptcp_worker+0x25e/0x320
 ? process_one_work+0x1a7/0x360
 ? worker_thread+0x30/0x390
 ? create_worker+0x1a0/0x1a0
 ? kthread+0x112/0x130
 ? kthread_flush_work_fn+0x10/0x10
 ? ret_from_fork+0x35/0x40
===========================================================================

In __mptcp_alloc_tx_skb skb was allocated and skb->tcp_tsorted_anchor will
be initialized, in under memory pressure situation sk_wmem_schedule will
return false and then kfree_skb. In this case skb->_skb_refdst is not null
because_skb_refdst and tcp_tsorted_anchor are stored in the same mem, and
kfree_skb will try to release dst and cause crash.

Fixes: f70cad10 ("mptcp: stop relying on tcp_tx_skb_cache")
Reviewed-by: default avatarPaolo Abeni <pabeni@redhat.com>
Signed-off-by: default avatarYonglong Li <liyonglong@chinatelecom.cn>
Signed-off-by: default avatarMat Martineau <mathew.j.martineau@linux.intel.com>
Link: https://lore.kernel.org/r/20220317220953.426024-1-mathew.j.martineau@linux.intel.comSigned-off-by: default avatarJakub Kicinski <kuba@kernel.org>
      3ef3905a
    • Jakub Kicinski's avatar
      Merge branch 'ipv4-handle-tos-and-scope-properly-for-icmp-redirects-and-pmtu-updates' · 03e2777c
      Jakub Kicinski authored 
      Guillaume Nault says:

====================
ipv4: Handle TOS and scope properly for ICMP redirects and PMTU updates

ICMPv4 PMTU and redirect handlers didn't properly initialise the
struct flowi4 they used for route lookups:

  * ECN bits sometimes weren't cleared from ->flowi4_tos.
  * The RTO_ONLINK flag wasn't taken into account for ->flowi4_scope.

In some special cases, this resulted in ICMP redirects and PMTU updates
not being taken into account because fib_lookup() couldn't retrieve the
correct route.
====================

Link: https://lore.kernel.org/r/cover.1647519748.git.gnault@redhat.comSigned-off-by: default avatarJakub Kicinski <kuba@kernel.org>
      03e2777c
    • Guillaume Nault's avatar
      selftest: net: Test IPv4 PMTU exceptions with DSCP and ECN · ec730c3e
      Guillaume Nault authored 
      Add two tests to pmtu.sh, for verifying that PMTU exceptions get
properly created for routes that don't belong to the main table.

A fib-rule based on the packet's DSCP field is used to jump to the
correct table. ECN shouldn't interfere with this process, so each test
has two components: one that only sets DSCP and one that sets both DSCP
and ECN.

One of the test triggers PMTU exceptions using ICMP Echo Requests, the
other using UDP packets (to test different handlers in the kernel).

A few adjustments are necessary in the rest of the script to allow
policy routing scenarios:

  * Add global variable rt_table that allows setup_routing_*() to
    add routes to a specific routing table. By default rt_table is set
    to "main", so existing tests don't need to be modified.

  * Another global variable, policy_mark, is used to define which
    dsfield value is used for policy routing. This variable has no
    effect on tests that don't use policy routing.

  * The UDP version of the test uses socat. So cleanup() now also need
    to kill socat PIDs.

  * route_get_dst_pmtu_from_exception() and route_get_dst_exception()
    now take an optional third argument specifying the dsfield. If
    not specified, 0 is used, so existing users don't need to be
    modified.
Signed-off-by: default avatarGuillaume Nault <gnault@redhat.com>
Reviewed-by: default avatarDavid Ahern <dsahern@kernel.org>
Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
      ec730c3e
    • Guillaume Nault's avatar
      ipv4: Fix route lookups when handling ICMP redirects and PMTU updates · 544b4dd5
      Guillaume Nault authored 
      The PMTU update and ICMP redirect helper functions initialise their fl4
variable with either __build_flow_key() or build_sk_flow_key(). These
initialisation functions always set ->flowi4_scope with
RT_SCOPE_UNIVERSE and might set the ECN bits of ->flowi4_tos. This is
not a problem when the route lookup is later done via
ip_route_output_key_hash(), which properly clears the ECN bits from
->flowi4_tos and initialises ->flowi4_scope based on the RTO_ONLINK
flag. However, some helpers call fib_lookup() directly, without
sanitising the tos and scope fields, so the route lookup can fail and,
as a result, the ICMP redirect or PMTU update aren't taken into
account.

Fix this by extracting the ->flowi4_tos and ->flowi4_scope sanitisation
code into ip_rt_fix_tos(), then use this function in handlers that call
fib_lookup() directly.

Note 1: We can't sanitise ->flowi4_tos and ->flowi4_scope in a central
place (like __build_flow_key() or flowi4_init_output()), because
ip_route_output_key_hash() expects non-sanitised values. When called
with sanitised values, it can erroneously overwrite RT_SCOPE_LINK with
RT_SCOPE_UNIVERSE in ->flowi4_scope. Therefore we have to be careful to
sanitise the values only for those paths that don't call
ip_route_output_key_hash().

Note 2: The problem is mostly about sanitising ->flowi4_tos. Having
->flowi4_scope initialised with RT_SCOPE_UNIVERSE instead of
RT_SCOPE_LINK probably wasn't really a problem: sockets with the
SOCK_LOCALROUTE flag set (those that'd result in RTO_ONLINK being set)
normally shouldn't receive ICMP redirects or PMTU updates.

Fixes: 4895c771 ("ipv4: Add FIB nexthop exceptions.")
Signed-off-by: default avatarGuillaume Nault <gnault@redhat.com>
Reviewed-by: default avatarDavid Ahern <dsahern@kernel.org>
Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
      544b4dd5
    • Jakub Kicinski's avatar
      Merge https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf · 6bd0c76b
      Jakub Kicinski authored 
      Daniel Borkmann says:

====================
pull-request: bpf 2022-03-18

We've added 2 non-merge commits during the last 18 day(s) which contain
a total of 2 files changed, 50 insertions(+), 20 deletions(-).

The main changes are:

1) Fix a race in XSK socket teardown code that can lead to a NULL pointer
   dereference, from Magnus.

2) Small MAINTAINERS doc update to remove Lorenz from sockmap, from Lorenz.

* https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf:
  xsk: Fix race at socket teardown
  bpf: Remove Lorenz Bauer from L7 BPF maintainers
====================

Link: https://lore.kernel.org/r/20220318152418.28638-1-daniel@iogearbox.netSigned-off-by: default avatarJakub Kicinski <kuba@kernel.org>
      6bd0c76b
    • David S. Miller's avatar
      Merge branch 'af_unix-OOB-fixes' · 9905eed4
      David S. Miller authored 
      Kuniyuki Iwashima says:

====================
af_unix: Fix some OOB implementation.

This series fixes some data-races and adds a missing feature around the
commit 314001f0 ("af_unix: Add OOB support").

Changelog:
  - v3:
    - Add the first patch

  - v2: https://lore.kernel.org/netdev/20220315054801.72035-1-kuniyu@amazon.co.jp/
    - Add READ_ONCE() to avoid a race reported by KCSAN (Eric)
    - Add IS_ENABLED(CONFIG_AF_UNIX_OOB) (Shoaib)

  - v1: https://lore.kernel.org/netdev/20220314052110.53634-1-kuniyu@amazon.co.jp/
====================
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      9905eed4
    • Kuniyuki Iwashima's avatar
      af_unix: Support POLLPRI for OOB. · d9a232d4
      Kuniyuki Iwashima authored 
      The commit 314001f0 ("af_unix: Add OOB support") introduced OOB for
AF_UNIX, but it lacks some changes for POLLPRI.  Let's add the missing
piece.

In the selftest, normal datagrams are sent followed by OOB data, so this
commit replaces `POLLIN | POLLPRI` with just `POLLPRI` in the first test
case.

Fixes: 314001f0 ("af_unix: Add OOB support")
Signed-off-by: default avatarKuniyuki Iwashima <kuniyu@amazon.co.jp>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      d9a232d4
    • Kuniyuki Iwashima's avatar
      af_unix: Fix some data-races around unix_sk(sk)->oob_skb. · e82025c6
      Kuniyuki Iwashima authored 
      Out-of-band data automatically places a "mark" showing wherein the
sequence the out-of-band data would have been.  If the out-of-band data
implies cancelling everything sent so far, the "mark" is helpful to flush
them.  When the socket's read pointer reaches the "mark", the ioctl() below
sets a non zero value to the arg `atmark`:

The out-of-band data is queued in sk->sk_receive_queue as well as ordinary
data and also saved in unix_sk(sk)->oob_skb.  It can be used to test if the
head of the receive queue is the out-of-band data meaning the socket is at
the "mark".

While testing that, unix_ioctl() reads unix_sk(sk)->oob_skb locklessly.
Thus, all accesses to oob_skb need some basic protection to avoid
load/store tearing which KCSAN detects when these are called concurrently:

  - ioctl(fd_a, SIOCATMARK, &atmark, sizeof(atmark))
  - send(fd_b_connected_to_a, buf, sizeof(buf), MSG_OOB)

BUG: KCSAN: data-race in unix_ioctl / unix_stream_sendmsg

write to 0xffff888003d9cff0 of 8 bytes by task 175 on cpu 1:
 unix_stream_sendmsg (net/unix/af_unix.c:2087 net/unix/af_unix.c:2191)
 sock_sendmsg (net/socket.c:705 net/socket.c:725)
 __sys_sendto (net/socket.c:2040)
 __x64_sys_sendto (net/socket.c:2048)
 do_syscall_64 (arch/x86/entry/common.c:50 arch/x86/entry/common.c:80)
 entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:113)

read to 0xffff888003d9cff0 of 8 bytes by task 176 on cpu 0:
 unix_ioctl (net/unix/af_unix.c:3101 (discriminator 1))
 sock_do_ioctl (net/socket.c:1128)
 sock_ioctl (net/socket.c:1242)
 __x64_sys_ioctl (fs/ioctl.c:52 fs/ioctl.c:874 fs/ioctl.c:860 fs/ioctl.c:860)
 do_syscall_64 (arch/x86/entry/common.c:50 arch/x86/entry/common.c:80)
 entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:113)

value changed: 0xffff888003da0c00 -> 0xffff888003da0d00

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 176 Comm: unix_race_oob_i Not tainted 5.17.0-rc5-59529-g83dc4c2a #12
Hardware name: Red Hat KVM, BIOS 1.11.0-2.amzn2 04/01/2014

Fixes: 314001f0 ("af_unix: Add OOB support")
Signed-off-by: default avatarKuniyuki Iwashima <kuniyu@amazon.co.jp>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      e82025c6
    • Sukadev Bhattiprolu's avatar
      ibmvnic: fix race between xmit and reset · 4219196d
      Sukadev Bhattiprolu authored 
      There is a race between reset and the transmit paths that can lead to
ibmvnic_xmit() accessing an scrq after it has been freed in the reset
path. It can result in a crash like:

	Kernel attempted to read user page (0) - exploit attempt? (uid: 0)
	BUG: Kernel NULL pointer dereference on read at 0x00000000
	Faulting instruction address: 0xc0080000016189f8
	Oops: Kernel access of bad area, sig: 11 [#1]
	...
	NIP [c0080000016189f8] ibmvnic_xmit+0x60/0xb60 [ibmvnic]
	LR [c000000000c0046c] dev_hard_start_xmit+0x11c/0x280
	Call Trace:
	[c008000001618f08] ibmvnic_xmit+0x570/0xb60 [ibmvnic] (unreliable)
	[c000000000c0046c] dev_hard_start_xmit+0x11c/0x280
	[c000000000c9cfcc] sch_direct_xmit+0xec/0x330
	[c000000000bfe640] __dev_xmit_skb+0x3a0/0x9d0
	[c000000000c00ad4] __dev_queue_xmit+0x394/0x730
	[c008000002db813c] __bond_start_xmit+0x254/0x450 [bonding]
	[c008000002db8378] bond_start_xmit+0x40/0xc0 [bonding]
	[c000000000c0046c] dev_hard_start_xmit+0x11c/0x280
	[c000000000c00ca4] __dev_queue_xmit+0x564/0x730
	[c000000000cf97e0] neigh_hh_output+0xd0/0x180
	[c000000000cfa69c] ip_finish_output2+0x31c/0x5c0
	[c000000000cfd244] __ip_queue_xmit+0x194/0x4f0
	[c000000000d2a3c4] __tcp_transmit_skb+0x434/0x9b0
	[c000000000d2d1e0] __tcp_retransmit_skb+0x1d0/0x6a0
	[c000000000d2d984] tcp_retransmit_skb+0x34/0x130
	[c000000000d310e8] tcp_retransmit_timer+0x388/0x6d0
	[c000000000d315ec] tcp_write_timer_handler+0x1bc/0x330
	[c000000000d317bc] tcp_write_timer+0x5c/0x200
	[c000000000243270] call_timer_fn+0x50/0x1c0
	[c000000000243704] __run_timers.part.0+0x324/0x460
	[c000000000243894] run_timer_softirq+0x54/0xa0
	[c000000000ea713c] __do_softirq+0x15c/0x3e0
	[c000000000166258] __irq_exit_rcu+0x158/0x190
	[c000000000166420] irq_exit+0x20/0x40
	[c00000000002853c] timer_interrupt+0x14c/0x2b0
	[c000000000009a00] decrementer_common_virt+0x210/0x220
	--- interrupt: 900 at plpar_hcall_norets_notrace+0x18/0x2c

The immediate cause of the crash is the access of tx_scrq in the following
snippet during a reset, where the tx_scrq can be either NULL or an address
that will soon be invalid:

	ibmvnic_xmit()
	{
		...
		tx_scrq = adapter->tx_scrq[queue_num];
		txq = netdev_get_tx_queue(netdev, queue_num);
		ind_bufp = &tx_scrq->ind_buf;

		if (test_bit(0, &adapter->resetting)) {
		...
	}

But beyond that, the call to ibmvnic_xmit() itself is not safe during a
reset and the reset path attempts to avoid this by stopping the queue in
ibmvnic_cleanup(). However just after the queue was stopped, an in-flight
ibmvnic_complete_tx() could have restarted the queue even as the reset is
progressing.

Since the queue was restarted we could get a call to ibmvnic_xmit() which
can then access the bad tx_scrq (or other fields).

We cannot however simply have ibmvnic_complete_tx() check the ->resetting
bit and skip starting the queue. This can race at the "back-end" of a good
reset which just restarted the queue but has not cleared the ->resetting
bit yet. If we skip restarting the queue due to ->resetting being true,
the queue would remain stopped indefinitely potentially leading to transmit
timeouts.

IOW ->resetting is too broad for this purpose. Instead use a new flag
that indicates whether or not the queues are active. Only the open/
reset paths control when the queues are active. ibmvnic_complete_tx()
and others wake up the queue only if the queue is marked active.

So we will have:
	A. reset/open thread in ibmvnic_cleanup() and __ibmvnic_open()

		->resetting = true
		->tx_queues_active = false
		disable tx queues
		...
		->tx_queues_active = true
		start tx queues

	B. Tx interrupt in ibmvnic_complete_tx():

		if (->tx_queues_active)
			netif_wake_subqueue();

To ensure that ->tx_queues_active and state of the queues are consistent,
we need a lock which:

	- must also be taken in the interrupt path (ibmvnic_complete_tx())
	- shared across the multiple queues in the adapter (so they don't
	  become serialized)

Use rcu_read_lock() and have the reset thread synchronize_rcu() after
updating the ->tx_queues_active state.

While here, consolidate a few boolean fields in ibmvnic_adapter for
better alignment.

Based on discussions with Brian King and Dany Madden.

Fixes: 7ed5b31f ("net/ibmvnic: prevent more than one thread from running in reset")
Reported-by: default avatarVaishnavi Bhat <vaish123@in.ibm.com>
Signed-off-by: default avatarSukadev Bhattiprolu <sukadev@linux.ibm.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      4219196d
    • David S. Miller's avatar
      Merge git://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf · 4fa331b4
      David S. Miller authored 
      Pablo Neira Ayuso says:

====================
Netfilter fixes for net

The following patchset contains Netfilter fixes for net:

1) Fix PPPoE and QinQ with flowtable inet family.

2) Missing register validation in nf_tables.

3) Initialize registers to avoid stack memleak to userspace.
====================
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      4fa331b4
  9. 17 Mar, 2022 16 commits
  11. 16 Mar, 2022 5 commits
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