In the Linux kernel, the following vulnerability has been resolved:
bpf: Prevent tail call between progs attached to different hooks
bpf progs can be attached to kernel functions, and the attached functions
can take different parameters or return different return values. If
prog attached to one kernel function tail calls prog attached to another
kernel function, the ctx access or return value verification could be
bypassed.
For example, if prog1 is attached to func1 which takes only 1 parameter
and prog2 is attached to func2 which takes two parameters. Since verifier
assumes the bpf ctx passed to prog2 is constructed based on func2's
prototype, verifier allows prog2 to access the second parameter from
the bpf ctx passed to it. The problem is that verifier does not prevent
prog1 from passing its bpf ctx to prog2 via tail call. In this case,
the bpf ctx passed to prog2 is constructed from func1 instead of func2,
that is, the assumption for ctx access verification is bypassed.
Another example, if BPF LSM prog1 is attached to hook file_alloc_security,
and BPF LSM prog2 is attached to hook bpf_lsm_audit_rule_known. Verifier
knows the return value rules for these two hooks, e.g. it is legal for
bpf_lsm_audit_rule_known to return positive number 1, and it is illegal
for file_alloc_security to return positive number. So verifier allows
prog2 to return positive number 1, but does not allow prog1 to return
positive number. The problem is that verifier does not prevent prog1
from calling prog2 via tail call. In this case, prog2's return value 1
will be used as the return value for prog1's hook file_alloc_security.
That is, the return value rule is bypassed.
This patch adds restriction for tail call to prevent such bypasses.
In the Linux kernel, the following vulnerability has been resolved:
driver core: bus: Fix double free in driver API bus_register()
For bus_register(), any error which happens after kset_register() will
cause that @priv are freed twice, fixed by setting @priv with NULL after
the first free.
In the Linux kernel, the following vulnerability has been resolved:
usb: typec: tipd: Free IRQ only if it was requested before
In polling mode, if no IRQ was requested there is no need to free it.
Call devm_free_irq() only if client->irq is set. This fixes the warning
caused by the tps6598x module removal:
WARNING: CPU: 2 PID: 333 at kernel/irq/devres.c:144 devm_free_irq+0x80/0x8c
...
...
Call trace:
devm_free_irq+0x80/0x8c
tps6598x_remove+0x28/0x88 [tps6598x]
i2c_device_remove+0x2c/0x9c
device_remove+0x4c/0x80
device_release_driver_internal+0x1cc/0x228
driver_detach+0x50/0x98
bus_remove_driver+0x6c/0xbc
driver_unregister+0x30/0x60
i2c_del_driver+0x54/0x64
tps6598x_i2c_driver_exit+0x18/0xc3c [tps6598x]
__arm64_sys_delete_module+0x184/0x264
invoke_syscall+0x48/0x110
el0_svc_common.constprop.0+0xc8/0xe8
do_el0_svc+0x20/0x2c
el0_svc+0x28/0x98
el0t_64_sync_handler+0x13c/0x158
el0t_64_sync+0x190/0x194
In the Linux kernel, the following vulnerability has been resolved:
serial: protect uart_port_dtr_rts() in uart_shutdown() too
Commit af224ca2df29 (serial: core: Prevent unsafe uart port access, part
3) added few uport == NULL checks. It added one to uart_shutdown(), so
the commit assumes, uport can be NULL in there. But right after that
protection, there is an unprotected "uart_port_dtr_rts(uport, false);"
call. That is invoked only if HUPCL is set, so I assume that is the
reason why we do not see lots of these reports.
Or it cannot be NULL at this point at all for some reason :P.
Until the above is investigated, stay on the safe side and move this
dereference to the if too.
I got this inconsistency from Coverity under CID 1585130. Thanks.
In the Linux kernel, the following vulnerability has been resolved:
thermal: core: Reference count the zone in thermal_zone_get_by_id()
There are places in the thermal netlink code where nothing prevents
the thermal zone object from going away while being accessed after it
has been returned by thermal_zone_get_by_id().
To address this, make thermal_zone_get_by_id() get a reference on the
thermal zone device object to be returned with the help of get_device(),
under thermal_list_lock, and adjust all of its callers to this change
with the help of the cleanup.h infrastructure.
In the Linux kernel, the following vulnerability has been resolved:
net: do not delay dst_entries_add() in dst_release()
dst_entries_add() uses per-cpu data that might be freed at netns
dismantle from ip6_route_net_exit() calling dst_entries_destroy()
Before ip6_route_net_exit() can be called, we release all
the dsts associated with this netns, via calls to dst_release(),
which waits an rcu grace period before calling dst_destroy()
dst_entries_add() use in dst_destroy() is racy, because
dst_entries_destroy() could have been called already.
Decrementing the number of dsts must happen sooner.
Notes:
1) in CONFIG_XFRM case, dst_destroy() can call
dst_release_immediate(child), this might also cause UAF
if the child does not have DST_NOCOUNT set.
IPSEC maintainers might take a look and see how to address this.
2) There is also discussion about removing this count of dst,
which might happen in future kernels.
In the Linux kernel, the following vulnerability has been resolved:
x86/mm/ident_map: Use gbpages only where full GB page should be mapped.
When ident_pud_init() uses only GB pages to create identity maps, large
ranges of addresses not actually requested can be included in the resulting
table; a 4K request will map a full GB. This can include a lot of extra
address space past that requested, including areas marked reserved by the
BIOS. That allows processor speculation into reserved regions, that on UV
systems can cause system halts.
Only use GB pages when map creation requests include the full GB page of
space. Fall back to using smaller 2M pages when only portions of a GB page
are included in the request.
No attempt is made to coalesce mapping requests. If a request requires a
map entry at the 2M (pmd) level, subsequent mapping requests within the
same 1G region will also be at the pmd level, even if adjacent or
overlapping such requests could have been combined to map a full GB page.
Existing usage starts with larger regions and then adds smaller regions, so
this should not have any great consequence.
In the Linux kernel, the following vulnerability has been resolved:
drm/amd/display: update DML2 policy EnhancedPrefetchScheduleAccelerationFinal DCN35
[WHY & HOW]
Mismatch in DCN35 DML2 cause bw validation failed to acquire unexpected DPP pipe to cause
grey screen and system hang. Remove EnhancedPrefetchScheduleAccelerationFinal value override
to match HW spec.
(cherry picked from commit 9dad21f910fcea2bdcff4af46159101d7f9cd8ba)