In the Linux kernel, the following vulnerability has been resolved:
bpf: Fix kmemleak warning for percpu hashmap
Vlad Poenaru reported the following kmemleak issue:
unreferenced object 0x606fd7c44ac8 (size 32):
backtrace (crc 0):
pcpu_alloc_noprof+0x730/0xeb0
bpf_map_alloc_percpu+0x69/0xc0
prealloc_init+0x9d/0x1b0
htab_map_alloc+0x363/0x510
map_create+0x215/0x3a0
__sys_bpf+0x16b/0x3e0
__x64_sys_bpf+0x18/0x20
do_syscall_64+0x7b/0x150
entry_SYSCALL_64_after_hwframe+0x4b/0x53
Further investigation shows the reason is due to not 8-byte aligned
store of percpu pointer in htab_elem_set_ptr():
*(void __percpu **)(l->key + key_size) = pptr;
Note that the whole htab_elem alignment is 8 (for x86_64). If the key_size
is 4, that means pptr is stored in a location which is 4 byte aligned but
not 8 byte aligned. In mm/kmemleak.c, scan_block() scans the memory based
on 8 byte stride, so it won't detect above pptr, hence reporting the memory
leak.
In htab_map_alloc(), we already have
htab->elem_size = sizeof(struct htab_elem) +
round_up(htab->map.key_size, 8);
if (percpu)
htab->elem_size += sizeof(void *);
else
htab->elem_size += round_up(htab->map.value_size, 8);
So storing pptr with 8-byte alignment won't cause any problem and can fix
kmemleak too.
The issue can be reproduced with bpf selftest as well:
1. Enable CONFIG_DEBUG_KMEMLEAK config
2. Add a getchar() before skel destroy in test_hash_map() in prog_tests/for_each.c.
The purpose is to keep map available so kmemleak can be detected.
3. run './test_progs -t for_each/hash_map &' and a kmemleak should be reported.
In the Linux kernel, the following vulnerability has been resolved:
crypto: null - Use spin lock instead of mutex
As the null algorithm may be freed in softirq context through
af_alg, use spin locks instead of mutexes to protect the default
null algorithm.
In the Linux kernel, the following vulnerability has been resolved:
driver core: fix potential NULL pointer dereference in dev_uevent()
If userspace reads "uevent" device attribute at the same time as another
threads unbinds the device from its driver, change to dev->driver from a
valid pointer to NULL may result in crash. Fix this by using READ_ONCE()
when fetching the pointer, and take bus' drivers klist lock to make sure
driver instance will not disappear while we access it.
Use WRITE_ONCE() when setting the driver pointer to ensure there is no
tearing.
In the Linux kernel, the following vulnerability has been resolved:
scsi: target: Fix WRITE_SAME No Data Buffer crash
In newer version of the SBC specs, we have a NDOB bit that indicates there
is no data buffer that gets written out. If this bit is set using commands
like "sg_write_same --ndob" we will crash in target_core_iblock/file's
execute_write_same handlers when we go to access the se_cmd->t_data_sg
because its NULL.
This patch adds a check for the NDOB bit in the common WRITE SAME code
because we don't support it. And, it adds a check for zero SG elements in
each handler in case the initiator tries to send a normal WRITE SAME with
no data buffer.
In the Linux kernel, the following vulnerability has been resolved:
SUNRPC: Fix a server shutdown leak
Fix a race where kthread_stop() may prevent the threadfn from ever getting
called. If that happens the svc_rqst will not be cleaned up.
In the Linux kernel, the following vulnerability has been resolved:
net: caif: Fix use-after-free in cfusbl_device_notify()
syzbot reported use-after-free in cfusbl_device_notify() [1]. This
causes a stack trace like below:
BUG: KASAN: use-after-free in cfusbl_device_notify+0x7c9/0x870 net/caif/caif_usb.c:138
Read of size 8 at addr ffff88807ac4e6f0 by task kworker/u4:6/1214
CPU: 0 PID: 1214 Comm: kworker/u4:6 Not tainted 5.19.0-rc3-syzkaller-00146-g92f20ff72066 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: netns cleanup_net
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
print_address_description.constprop.0.cold+0xeb/0x467 mm/kasan/report.c:313
print_report mm/kasan/report.c:429 [inline]
kasan_report.cold+0xf4/0x1c6 mm/kasan/report.c:491
cfusbl_device_notify+0x7c9/0x870 net/caif/caif_usb.c:138
notifier_call_chain+0xb5/0x200 kernel/notifier.c:87
call_netdevice_notifiers_info+0xb5/0x130 net/core/dev.c:1945
call_netdevice_notifiers_extack net/core/dev.c:1983 [inline]
call_netdevice_notifiers net/core/dev.c:1997 [inline]
netdev_wait_allrefs_any net/core/dev.c:10227 [inline]
netdev_run_todo+0xbc0/0x10f0 net/core/dev.c:10341
default_device_exit_batch+0x44e/0x590 net/core/dev.c:11334
ops_exit_list+0x125/0x170 net/core/net_namespace.c:167
cleanup_net+0x4ea/0xb00 net/core/net_namespace.c:594
process_one_work+0x996/0x1610 kernel/workqueue.c:2289
worker_thread+0x665/0x1080 kernel/workqueue.c:2436
kthread+0x2e9/0x3a0 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:302
</TASK>
When unregistering a net device, unregister_netdevice_many_notify()
sets the device's reg_state to NETREG_UNREGISTERING, calls notifiers
with NETDEV_UNREGISTER, and adds the device to the todo list.
Later on, devices in the todo list are processed by netdev_run_todo().
netdev_run_todo() waits devices' reference count become 1 while
rebdoadcasting NETDEV_UNREGISTER notification.
When cfusbl_device_notify() is called with NETDEV_UNREGISTER multiple
times, the parent device might be freed. This could cause UAF.
Processing NETDEV_UNREGISTER multiple times also causes inbalance of
reference count for the module.
This patch fixes the issue by accepting only first NETDEV_UNREGISTER
notification.
In the Linux kernel, the following vulnerability has been resolved:
nfc: fdp: add null check of devm_kmalloc_array in fdp_nci_i2c_read_device_properties
devm_kmalloc_array may fails, *fw_vsc_cfg might be null and cause
out-of-bounds write in device_property_read_u8_array later.
In the Linux kernel, the following vulnerability has been resolved:
scsi: core: Remove the /proc/scsi/${proc_name} directory earlier
Remove the /proc/scsi/${proc_name} directory earlier to fix a race
condition between unloading and reloading kernel modules. This fixes a bug
introduced in 2009 by commit 77c019768f06 ("[SCSI] fix /proc memory leak in
the SCSI core").
Fix the following kernel warning:
proc_dir_entry 'scsi/scsi_debug' already registered
WARNING: CPU: 19 PID: 27986 at fs/proc/generic.c:376 proc_register+0x27d/0x2e0
Call Trace:
proc_mkdir+0xb5/0xe0
scsi_proc_hostdir_add+0xb5/0x170
scsi_host_alloc+0x683/0x6c0
sdebug_driver_probe+0x6b/0x2d0 [scsi_debug]
really_probe+0x159/0x540
__driver_probe_device+0xdc/0x230
driver_probe_device+0x4f/0x120
__device_attach_driver+0xef/0x180
bus_for_each_drv+0xe5/0x130
__device_attach+0x127/0x290
device_initial_probe+0x17/0x20
bus_probe_device+0x110/0x130
device_add+0x673/0xc80
device_register+0x1e/0x30
sdebug_add_host_helper+0x1a7/0x3b0 [scsi_debug]
scsi_debug_init+0x64f/0x1000 [scsi_debug]
do_one_initcall+0xd7/0x470
do_init_module+0xe7/0x330
load_module+0x122a/0x12c0
__do_sys_finit_module+0x124/0x1a0
__x64_sys_finit_module+0x46/0x50
do_syscall_64+0x38/0x80
entry_SYSCALL_64_after_hwframe+0x46/0xb0
In the Linux kernel, the following vulnerability has been resolved:
tcp: tcp_make_synack() can be called from process context
tcp_rtx_synack() now could be called in process context as explained in
0a375c822497 ("tcp: tcp_rtx_synack() can be called from process
context").
tcp_rtx_synack() might call tcp_make_synack(), which will touch per-CPU
variables with preemption enabled. This causes the following BUG:
BUG: using __this_cpu_add() in preemptible [00000000] code: ThriftIO1/5464
caller is tcp_make_synack+0x841/0xac0
Call Trace:
<TASK>
dump_stack_lvl+0x10d/0x1a0
check_preemption_disabled+0x104/0x110
tcp_make_synack+0x841/0xac0
tcp_v6_send_synack+0x5c/0x450
tcp_rtx_synack+0xeb/0x1f0
inet_rtx_syn_ack+0x34/0x60
tcp_check_req+0x3af/0x9e0
tcp_rcv_state_process+0x59b/0x2030
tcp_v6_do_rcv+0x5f5/0x700
release_sock+0x3a/0xf0
tcp_sendmsg+0x33/0x40
____sys_sendmsg+0x2f2/0x490
__sys_sendmsg+0x184/0x230
do_syscall_64+0x3d/0x90
Avoid calling __TCP_INC_STATS() with will touch per-cpu variables. Use
TCP_INC_STATS() which is safe to be called from context switch.