| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| In the Linux kernel, the following vulnerability has been resolved:
scsi: iscsi: iscsi_tcp: Fix null-ptr-deref while calling getpeername()
Fix a NULL pointer crash that occurs when we are freeing the socket at the
same time we access it via sysfs.
The problem is that:
1. iscsi_sw_tcp_conn_get_param() and iscsi_sw_tcp_host_get_param() take
the frwd_lock and do sock_hold() then drop the frwd_lock. sock_hold()
does a get on the "struct sock".
2. iscsi_sw_tcp_release_conn() does sockfd_put() which does the last put
on the "struct socket" and that does __sock_release() which sets the
sock->ops to NULL.
3. iscsi_sw_tcp_conn_get_param() and iscsi_sw_tcp_host_get_param() then
call kernel_getpeername() which accesses the NULL sock->ops.
Above we do a get on the "struct sock", but we needed a get on the "struct
socket". Originally, we just held the frwd_lock the entire time but in
commit bcf3a2953d36 ("scsi: iscsi: iscsi_tcp: Avoid holding spinlock while
calling getpeername()") we switched to refcount based because the network
layer changed and started taking a mutex in that path, so we could no
longer hold the frwd_lock.
Instead of trying to maintain multiple refcounts, this just has us use a
mutex for accessing the socket in the interface code paths. |
| In the Linux kernel, the following vulnerability has been resolved:
drm/vmwgfx: Validate the box size for the snooped cursor
Invalid userspace dma surface copies could potentially overflow
the memcpy from the surface to the snooped image leading to crashes.
To fix it the dimensions of the copybox have to be validated
against the expected size of the snooped cursor. |
| In the Linux kernel, the following vulnerability has been resolved:
net/tunnel: wait until all sk_user_data reader finish before releasing the sock
There is a race condition in vxlan that when deleting a vxlan device
during receiving packets, there is a possibility that the sock is
released after getting vxlan_sock vs from sk_user_data. Then in
later vxlan_ecn_decapsulate(), vxlan_get_sk_family() we will got
NULL pointer dereference. e.g.
#0 [ffffa25ec6978a38] machine_kexec at ffffffff8c669757
#1 [ffffa25ec6978a90] __crash_kexec at ffffffff8c7c0a4d
#2 [ffffa25ec6978b58] crash_kexec at ffffffff8c7c1c48
#3 [ffffa25ec6978b60] oops_end at ffffffff8c627f2b
#4 [ffffa25ec6978b80] page_fault_oops at ffffffff8c678fcb
#5 [ffffa25ec6978bd8] exc_page_fault at ffffffff8d109542
#6 [ffffa25ec6978c00] asm_exc_page_fault at ffffffff8d200b62
[exception RIP: vxlan_ecn_decapsulate+0x3b]
RIP: ffffffffc1014e7b RSP: ffffa25ec6978cb0 RFLAGS: 00010246
RAX: 0000000000000008 RBX: ffff8aa000888000 RCX: 0000000000000000
RDX: 000000000000000e RSI: ffff8a9fc7ab803e RDI: ffff8a9fd1168700
RBP: ffff8a9fc7ab803e R8: 0000000000700000 R9: 00000000000010ae
R10: ffff8a9fcb748980 R11: 0000000000000000 R12: ffff8a9fd1168700
R13: ffff8aa000888000 R14: 00000000002a0000 R15: 00000000000010ae
ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018
#7 [ffffa25ec6978ce8] vxlan_rcv at ffffffffc10189cd [vxlan]
#8 [ffffa25ec6978d90] udp_queue_rcv_one_skb at ffffffff8cfb6507
#9 [ffffa25ec6978dc0] udp_unicast_rcv_skb at ffffffff8cfb6e45
#10 [ffffa25ec6978dc8] __udp4_lib_rcv at ffffffff8cfb8807
#11 [ffffa25ec6978e20] ip_protocol_deliver_rcu at ffffffff8cf76951
#12 [ffffa25ec6978e48] ip_local_deliver at ffffffff8cf76bde
#13 [ffffa25ec6978ea0] __netif_receive_skb_one_core at ffffffff8cecde9b
#14 [ffffa25ec6978ec8] process_backlog at ffffffff8cece139
#15 [ffffa25ec6978f00] __napi_poll at ffffffff8ceced1a
#16 [ffffa25ec6978f28] net_rx_action at ffffffff8cecf1f3
#17 [ffffa25ec6978fa0] __softirqentry_text_start at ffffffff8d4000ca
#18 [ffffa25ec6978ff0] do_softirq at ffffffff8c6fbdc3
Reproducer: https://github.com/Mellanox/ovs-tests/blob/master/test-ovs-vxlan-remove-tunnel-during-traffic.sh
Fix this by waiting for all sk_user_data reader to finish before
releasing the sock. |
| In the Linux kernel, the following vulnerability has been resolved:
drm/amdkfd: Fix kfd_process_device_init_vm error handling
Should only destroy the ib_mem and let process cleanup worker to free
the outstanding BOs. Reset the pointer in pdd->qpd structure, to avoid
NULL pointer access in process destroy worker.
BUG: kernel NULL pointer dereference, address: 0000000000000010
Call Trace:
amdgpu_amdkfd_gpuvm_unmap_gtt_bo_from_kernel+0x46/0xb0 [amdgpu]
kfd_process_device_destroy_cwsr_dgpu+0x40/0x70 [amdgpu]
kfd_process_destroy_pdds+0x71/0x190 [amdgpu]
kfd_process_wq_release+0x2a2/0x3b0 [amdgpu]
process_one_work+0x2a1/0x600
worker_thread+0x39/0x3d0 |
| In the Linux kernel, the following vulnerability has been resolved:
dmaengine: sf-pdma: Add multithread support for a DMA channel
When we get a DMA channel and try to use it in multiple threads it
will cause oops and hanging the system.
% echo 64 > /sys/module/dmatest/parameters/threads_per_chan
% echo 10000 > /sys/module/dmatest/parameters/iterations
% echo 1 > /sys/module/dmatest/parameters/run
[ 89.480664] Unable to handle kernel NULL pointer dereference at virtual
address 00000000000000a0
[ 89.488725] Oops [#1]
[ 89.494708] CPU: 2 PID: 1008 Comm: dma0chan0-copy0 Not tainted
5.17.0-rc5
[ 89.509385] epc : vchan_find_desc+0x32/0x46
[ 89.513553] ra : sf_pdma_tx_status+0xca/0xd6
This happens because of data race. Each thread rewrite channels's
descriptor as soon as device_prep_dma_memcpy() is called. It leads to the
situation when the driver thinks that it uses right descriptor that
actually is freed or substituted for other one.
With current fixes a descriptor changes its value only when it has
been used. A new descriptor is acquired from vc->desc_issued queue that
is already filled with descriptors that are ready to be sent. Threads
have no direct access to DMA channel descriptor. Now it is just possible
to queue a descriptor for further processing. |
| In the Linux kernel, the following vulnerability has been resolved:
ftrace: Fix NULL pointer dereference in is_ftrace_trampoline when ftrace is dead
ftrace_startup does not remove ops from ftrace_ops_list when
ftrace_startup_enable fails:
register_ftrace_function
ftrace_startup
__register_ftrace_function
...
add_ftrace_ops(&ftrace_ops_list, ops)
...
...
ftrace_startup_enable // if ftrace failed to modify, ftrace_disabled is set to 1
...
return 0 // ops is in the ftrace_ops_list.
When ftrace_disabled = 1, unregister_ftrace_function simply returns without doing anything:
unregister_ftrace_function
ftrace_shutdown
if (unlikely(ftrace_disabled))
return -ENODEV; // return here, __unregister_ftrace_function is not executed,
// as a result, ops is still in the ftrace_ops_list
__unregister_ftrace_function
...
If ops is dynamically allocated, it will be free later, in this case,
is_ftrace_trampoline accesses NULL pointer:
is_ftrace_trampoline
ftrace_ops_trampoline
do_for_each_ftrace_op(op, ftrace_ops_list) // OOPS! op may be NULL!
Syzkaller reports as follows:
[ 1203.506103] BUG: kernel NULL pointer dereference, address: 000000000000010b
[ 1203.508039] #PF: supervisor read access in kernel mode
[ 1203.508798] #PF: error_code(0x0000) - not-present page
[ 1203.509558] PGD 800000011660b067 P4D 800000011660b067 PUD 130fb8067 PMD 0
[ 1203.510560] Oops: 0000 [#1] SMP KASAN PTI
[ 1203.511189] CPU: 6 PID: 29532 Comm: syz-executor.2 Tainted: G B W 5.10.0 #8
[ 1203.512324] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014
[ 1203.513895] RIP: 0010:is_ftrace_trampoline+0x26/0xb0
[ 1203.514644] Code: ff eb d3 90 41 55 41 54 49 89 fc 55 53 e8 f2 00 fd ff 48 8b 1d 3b 35 5d 03 e8 e6 00 fd ff 48 8d bb 90 00 00 00 e8 2a 81 26 00 <48> 8b ab 90 00 00 00 48 85 ed 74 1d e8 c9 00 fd ff 48 8d bb 98 00
[ 1203.518838] RSP: 0018:ffffc900012cf960 EFLAGS: 00010246
[ 1203.520092] RAX: 0000000000000000 RBX: 000000000000007b RCX: ffffffff8a331866
[ 1203.521469] RDX: 0000000000000000 RSI: 0000000000000008 RDI: 000000000000010b
[ 1203.522583] RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffff8df18b07
[ 1203.523550] R10: fffffbfff1be3160 R11: 0000000000000001 R12: 0000000000478399
[ 1203.524596] R13: 0000000000000000 R14: ffff888145088000 R15: 0000000000000008
[ 1203.525634] FS: 00007f429f5f4700(0000) GS:ffff8881daf00000(0000) knlGS:0000000000000000
[ 1203.526801] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 1203.527626] CR2: 000000000000010b CR3: 0000000170e1e001 CR4: 00000000003706e0
[ 1203.528611] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 1203.529605] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Therefore, when ftrace_startup_enable fails, we need to rollback registration
process and remove ops from ftrace_ops_list. |
| In the Linux kernel, the following vulnerability has been resolved:
HID: nintendo: fix rumble worker null pointer deref
We can dereference a null pointer trying to queue work to a destroyed
workqueue.
If the device is disconnected, nintendo_hid_remove is called, in which
the rumble_queue is destroyed. Avoid using that queue to defer rumble
work once the controller state is set to JOYCON_CTLR_STATE_REMOVED.
This eliminates the null pointer dereference. |
| In the Linux kernel, the following vulnerability has been resolved:
Revert "usb: typec: ucsi: add a common function ucsi_unregister_connectors()"
The recent commit 87d0e2f41b8c ("usb: typec: ucsi: add a common
function ucsi_unregister_connectors()") introduced a regression that
caused NULL dereference at reading the power supply sysfs. It's a
stale sysfs entry that should have been removed but remains with NULL
ops. The commit changed the error handling to skip the entries after
a NULL con->wq, and this leaves the power device unreleased.
For addressing the regression, the straight revert is applied here.
Further code improvements can be done from the scratch again. |
| In the Linux kernel, the following vulnerability has been resolved:
IB/hfi1: Correctly move list in sc_disable()
Commit 13bac861952a ("IB/hfi1: Fix abba locking issue with sc_disable()")
incorrectly tries to move a list from one list head to another. The
result is a kernel crash.
The crash is triggered when a link goes down and there are waiters for a
send to complete. The following signature is seen:
BUG: kernel NULL pointer dereference, address: 0000000000000030
[...]
Call Trace:
sc_disable+0x1ba/0x240 [hfi1]
pio_freeze+0x3d/0x60 [hfi1]
handle_freeze+0x27/0x1b0 [hfi1]
process_one_work+0x1b0/0x380
? process_one_work+0x380/0x380
worker_thread+0x30/0x360
? process_one_work+0x380/0x380
kthread+0xd7/0x100
? kthread_complete_and_exit+0x20/0x20
ret_from_fork+0x1f/0x30
The fix is to use the correct call to move the list. |
| In the Linux kernel, the following vulnerability has been resolved:
SUNRPC: Fix null-ptr-deref when xps sysfs alloc failed
There is a null-ptr-deref when xps sysfs alloc failed:
BUG: KASAN: null-ptr-deref in sysfs_do_create_link_sd+0x40/0xd0
Read of size 8 at addr 0000000000000030 by task gssproxy/457
CPU: 5 PID: 457 Comm: gssproxy Not tainted 6.0.0-09040-g02357b27ee03 #9
Call Trace:
<TASK>
dump_stack_lvl+0x34/0x44
kasan_report+0xa3/0x120
sysfs_do_create_link_sd+0x40/0xd0
rpc_sysfs_client_setup+0x161/0x1b0
rpc_new_client+0x3fc/0x6e0
rpc_create_xprt+0x71/0x220
rpc_create+0x1d4/0x350
gssp_rpc_create+0xc3/0x160
set_gssp_clnt+0xbc/0x140
write_gssp+0x116/0x1a0
proc_reg_write+0xd6/0x130
vfs_write+0x177/0x690
ksys_write+0xb9/0x150
do_syscall_64+0x35/0x80
entry_SYSCALL_64_after_hwframe+0x46/0xb0
When the xprt_switch sysfs alloc failed, should not add xprt and
switch sysfs to it, otherwise, maybe null-ptr-deref; also initialize
the 'xps_sysfs' to NULL to avoid oops when destroy it. |
| In the Linux kernel, the following vulnerability has been resolved:
ALSA: pcm: oss: Fix race at SNDCTL_DSP_SYNC
There is a small race window at snd_pcm_oss_sync() that is called from
OSS PCM SNDCTL_DSP_SYNC ioctl; namely the function calls
snd_pcm_oss_make_ready() at first, then takes the params_lock mutex
for the rest. When the stream is set up again by another thread
between them, it leads to inconsistency, and may result in unexpected
results such as NULL dereference of OSS buffer as a fuzzer spotted
recently.
The fix is simply to cover snd_pcm_oss_make_ready() call into the same
params_lock mutex with snd_pcm_oss_make_ready_locked() variant. |
| In the Linux kernel, the following vulnerability has been resolved:
tipc: move bc link creation back to tipc_node_create
Shuang Li reported a NULL pointer dereference crash:
[] BUG: kernel NULL pointer dereference, address: 0000000000000068
[] RIP: 0010:tipc_link_is_up+0x5/0x10 [tipc]
[] Call Trace:
[] <IRQ>
[] tipc_bcast_rcv+0xa2/0x190 [tipc]
[] tipc_node_bc_rcv+0x8b/0x200 [tipc]
[] tipc_rcv+0x3af/0x5b0 [tipc]
[] tipc_udp_recv+0xc7/0x1e0 [tipc]
It was caused by the 'l' passed into tipc_bcast_rcv() is NULL. When it
creates a node in tipc_node_check_dest(), after inserting the new node
into hashtable in tipc_node_create(), it creates the bc link. However,
there is a gap between this insert and bc link creation, a bc packet
may come in and get the node from the hashtable then try to dereference
its bc link, which is NULL.
This patch is to fix it by moving the bc link creation before inserting
into the hashtable.
Note that for a preliminary node becoming "real", the bc link creation
should also be called before it's rehashed, as we don't create it for
preliminary nodes. |
| In the Linux kernel, the following vulnerability has been resolved:
scsi: lpfc: Fix null pointer dereference after failing to issue FLOGI and PLOGI
If lpfc_issue_els_flogi() fails and returns non-zero status, the node
reference count is decremented to trigger the release of the nodelist
structure. However, if there is a prior registration or dev-loss-evt work
pending, the node may be released prematurely. When dev-loss-evt
completes, the released node is referenced causing a use-after-free null
pointer dereference.
Similarly, when processing non-zero ELS PLOGI completion status in
lpfc_cmpl_els_plogi(), the ndlp flags are checked for a transport
registration before triggering node removal. If dev-loss-evt work is
pending, the node may be released prematurely and a subsequent call to
lpfc_dev_loss_tmo_handler() results in a use after free ndlp dereference.
Add test for pending dev-loss before decrementing the node reference count
for FLOGI, PLOGI, PRLI, and ADISC handling. |
| In the Linux kernel, the following vulnerability has been resolved:
f2fs: fix dereference of stale list iterator after loop body
The list iterator variable will be a bogus pointer if no break was hit.
Dereferencing it (cur->page in this case) could load an out-of-bounds/undefined
value making it unsafe to use that in the comparision to determine if the
specific element was found.
Since 'cur->page' *can* be out-ouf-bounds it cannot be guaranteed that
by chance (or intention of an attacker) it matches the value of 'page'
even though the correct element was not found.
This is fixed by using a separate list iterator variable for the loop
and only setting the original variable if a suitable element was found.
Then determing if the element was found is simply checking if the
variable is set. |
| In the Linux kernel, the following vulnerability has been resolved:
xprtrdma: treat all calls not a bcall when bc_serv is NULL
When a rdma server returns a fault format reply, nfs v3 client may
treats it as a bcall when bc service is not exist.
The debug message at rpcrdma_bc_receive_call are,
[56579.837169] RPC: rpcrdma_bc_receive_call: callback XID
00000001, length=20
[56579.837174] RPC: rpcrdma_bc_receive_call: 00 00 00 01 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 04
After that, rpcrdma_bc_receive_call will meets NULL pointer as,
[ 226.057890] BUG: unable to handle kernel NULL pointer dereference at
00000000000000c8
...
[ 226.058704] RIP: 0010:_raw_spin_lock+0xc/0x20
...
[ 226.059732] Call Trace:
[ 226.059878] rpcrdma_bc_receive_call+0x138/0x327 [rpcrdma]
[ 226.060011] __ib_process_cq+0x89/0x170 [ib_core]
[ 226.060092] ib_cq_poll_work+0x26/0x80 [ib_core]
[ 226.060257] process_one_work+0x1a7/0x360
[ 226.060367] ? create_worker+0x1a0/0x1a0
[ 226.060440] worker_thread+0x30/0x390
[ 226.060500] ? create_worker+0x1a0/0x1a0
[ 226.060574] kthread+0x116/0x130
[ 226.060661] ? kthread_flush_work_fn+0x10/0x10
[ 226.060724] ret_from_fork+0x35/0x40
... |
| In the Linux kernel, the following vulnerability has been resolved:
nbd: call genl_unregister_family() first in nbd_cleanup()
Otherwise there may be race between module removal and the handling of
netlink command, which can lead to the oops as shown below:
BUG: kernel NULL pointer dereference, address: 0000000000000098
Oops: 0002 [#1] SMP PTI
CPU: 1 PID: 31299 Comm: nbd-client Tainted: G E 5.14.0-rc4
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996)
RIP: 0010:down_write+0x1a/0x50
Call Trace:
start_creating+0x89/0x130
debugfs_create_dir+0x1b/0x130
nbd_start_device+0x13d/0x390 [nbd]
nbd_genl_connect+0x42f/0x748 [nbd]
genl_family_rcv_msg_doit.isra.0+0xec/0x150
genl_rcv_msg+0xe5/0x1e0
netlink_rcv_skb+0x55/0x100
genl_rcv+0x29/0x40
netlink_unicast+0x1a8/0x250
netlink_sendmsg+0x21b/0x430
____sys_sendmsg+0x2a4/0x2d0
___sys_sendmsg+0x81/0xc0
__sys_sendmsg+0x62/0xb0
__x64_sys_sendmsg+0x1f/0x30
do_syscall_64+0x3b/0xc0
entry_SYSCALL_64_after_hwframe+0x44/0xae
Modules linked in: nbd(E-) |
| In the Linux kernel, the following vulnerability has been resolved:
exec: Force single empty string when argv is empty
Quoting[1] Ariadne Conill:
"In several other operating systems, it is a hard requirement that the
second argument to execve(2) be the name of a program, thus prohibiting
a scenario where argc < 1. POSIX 2017 also recommends this behaviour,
but it is not an explicit requirement[2]:
The argument arg0 should point to a filename string that is
associated with the process being started by one of the exec
functions.
...
Interestingly, Michael Kerrisk opened an issue about this in 2008[3],
but there was no consensus to support fixing this issue then.
Hopefully now that CVE-2021-4034 shows practical exploitative use[4]
of this bug in a shellcode, we can reconsider.
This issue is being tracked in the KSPP issue tracker[5]."
While the initial code searches[6][7] turned up what appeared to be
mostly corner case tests, trying to that just reject argv == NULL
(or an immediately terminated pointer list) quickly started tripping[8]
existing userspace programs.
The next best approach is forcing a single empty string into argv and
adjusting argc to match. The number of programs depending on argc == 0
seems a smaller set than those calling execve with a NULL argv.
Account for the additional stack space in bprm_stack_limits(). Inject an
empty string when argc == 0 (and set argc = 1). Warn about the case so
userspace has some notice about the change:
process './argc0' launched './argc0' with NULL argv: empty string added
Additionally WARN() and reject NULL argv usage for kernel threads.
[1] https://lore.kernel.org/lkml/20220127000724.15106-1-ariadne@dereferenced.org/
[2] https://pubs.opengroup.org/onlinepubs/9699919799/functions/exec.html
[3] https://bugzilla.kernel.org/show_bug.cgi?id=8408
[4] https://www.qualys.com/2022/01/25/cve-2021-4034/pwnkit.txt
[5] https://github.com/KSPP/linux/issues/176
[6] https://codesearch.debian.net/search?q=execve%5C+*%5C%28%5B%5E%2C%5D%2B%2C+*NULL&literal=0
[7] https://codesearch.debian.net/search?q=execlp%3F%5Cs*%5C%28%5B%5E%2C%5D%2B%2C%5Cs*NULL&literal=0
[8] https://lore.kernel.org/lkml/20220131144352.GE16385@xsang-OptiPlex-9020/ |
| In the Linux kernel, the following vulnerability has been resolved:
xsk: Fix race at socket teardown
Fix a race in the xsk socket teardown code that can lead to a NULL pointer
dereference splat. The current xsk unbind code in xsk_unbind_dev() starts by
setting xs->state to XSK_UNBOUND, sets xs->dev to NULL and then waits for any
NAPI processing to terminate using synchronize_net(). After that, the release
code starts to tear down the socket state and free allocated memory.
BUG: kernel NULL pointer dereference, address: 00000000000000c0
PGD 8000000932469067 P4D 8000000932469067 PUD 0
Oops: 0000 [#1] PREEMPT SMP PTI
CPU: 25 PID: 69132 Comm: grpcpp_sync_ser Tainted: G I 5.16.0+ #2
Hardware name: Dell Inc. PowerEdge R730/0599V5, BIOS 1.2.10 03/09/2015
RIP: 0010:__xsk_sendmsg+0x2c/0x690
[...]
RSP: 0018:ffffa2348bd13d50 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000040 RCX: ffff8d5fc632d258
RDX: 0000000000400000 RSI: ffffa2348bd13e10 RDI: ffff8d5fc5489800
RBP: ffffa2348bd13db0 R08: 0000000000000000 R09: 00007ffffffff000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff8d5fc5489800
R13: ffff8d5fcb0f5140 R14: ffff8d5fcb0f5140 R15: 0000000000000000
FS: 00007f991cff9400(0000) GS:ffff8d6f1f700000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000000000c0 CR3: 0000000114888005 CR4: 00000000001706e0
Call Trace:
<TASK>
? aa_sk_perm+0x43/0x1b0
xsk_sendmsg+0xf0/0x110
sock_sendmsg+0x65/0x70
__sys_sendto+0x113/0x190
? debug_smp_processor_id+0x17/0x20
? fpregs_assert_state_consistent+0x23/0x50
? exit_to_user_mode_prepare+0xa5/0x1d0
__x64_sys_sendto+0x29/0x30
do_syscall_64+0x3b/0xc0
entry_SYSCALL_64_after_hwframe+0x44/0xae
There are two problems with the current code. First, setting xs->dev to NULL
before waiting for all users to stop using the socket is not correct. The
entry to the data plane functions xsk_poll(), xsk_sendmsg(), and xsk_recvmsg()
are all guarded by a test that xs->state is in the state XSK_BOUND and if not,
it returns right away. But one process might have passed this test but still
have not gotten to the point in which it uses xs->dev in the code. In this
interim, a second process executing xsk_unbind_dev() might have set xs->dev to
NULL which will lead to a crash for the first process. The solution here is
just to get rid of this NULL assignment since it is not used anymore. Before
commit 42fddcc7c64b ("xsk: use state member for socket synchronization"),
xs->dev was the gatekeeper to admit processes into the data plane functions,
but it was replaced with the state variable xs->state in the aforementioned
commit.
The second problem is that synchronize_net() does not wait for any process in
xsk_poll(), xsk_sendmsg(), or xsk_recvmsg() to complete, which means that the
state they rely on might be cleaned up prematurely. This can happen when the
notifier gets called (at driver unload for example) as it uses xsk_unbind_dev().
Solve this by extending the RCU critical region from just the ndo_xsk_wakeup
to the whole functions mentioned above, so that both the test of xs->state ==
XSK_BOUND and the last use of any member of xs is covered by the RCU critical
section. This will guarantee that when synchronize_net() completes, there will
be no processes left executing xsk_poll(), xsk_sendmsg(), or xsk_recvmsg() and
state can be cleaned up safely. Note that we need to drop the RCU lock for the
skb xmit path as it uses functions that might sleep. Due to this, we have to
retest the xs->state after we grab the mutex that protects the skb xmit code
from, among a number of things, an xsk_unbind_dev() being executed from the
notifier at the same time. |
| In the Linux kernel, the following vulnerability has been resolved:
scsi: qla2xxx: Implement ref count for SRB
The timeout handler and the done function are racing. When
qla2x00_async_iocb_timeout() starts to run it can be preempted by the
normal response path (via the firmware?). qla24xx_async_gpsc_sp_done()
releases the SRB unconditionally. When scheduling back to
qla2x00_async_iocb_timeout() qla24xx_async_abort_cmd() will access an freed
sp->qpair pointer:
qla2xxx [0000:83:00.0]-2871:0: Async-gpsc timeout - hdl=63d portid=234500 50:06:0e:80:08:77:b6:21.
qla2xxx [0000:83:00.0]-2853:0: Async done-gpsc res 0, WWPN 50:06:0e:80:08:77:b6:21
qla2xxx [0000:83:00.0]-2854:0: Async-gpsc OUT WWPN 20:45:00:27:f8:75:33:00 speeds=2c00 speed=0400.
qla2xxx [0000:83:00.0]-28d8:0: qla24xx_handle_gpsc_event 50:06:0e:80:08:77:b6:21 DS 7 LS 6 rc 0 login 1|1 rscn 1|0 lid 5
BUG: unable to handle kernel NULL pointer dereference at 0000000000000004
IP: qla24xx_async_abort_cmd+0x1b/0x1c0 [qla2xxx]
Obvious solution to this is to introduce a reference counter. One reference
is taken for the normal code path (the 'good' case) and one for the timeout
path. As we always race between the normal good case and the timeout/abort
handler we need to serialize it. Also we cannot assume any order between
the handlers. Since this is slow path we can use proper synchronization via
locks.
When we are able to cancel a timer (del_timer returns 1) we know there
can't be any error handling in progress because the timeout handler hasn't
expired yet, thus we can safely decrement the refcounter by one.
If we are not able to cancel the timer, we know an abort handler is
running. We have to make sure we call sp->done() in the abort handlers
before calling kref_put(). |
| In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: hci_event: Ignore multiple conn complete events
When one of the three connection complete events is received multiple
times for the same handle, the device is registered multiple times which
leads to memory corruptions. Therefore, consequent events for a single
connection are ignored.
The conn->state can hold different values, therefore HCI_CONN_HANDLE_UNSET
is introduced to identify new connections. To make sure the events do not
contain this or another invalid handle HCI_CONN_HANDLE_MAX and checks
are introduced.
Buglink: https://bugzilla.kernel.org/show_bug.cgi?id=215497 |
