Linux: >> Linux Kernel >> 4.1.26 Security Vulnerabilities
In the Linux kernel, the following vulnerability has been resolved:
xen/gntdev: Accommodate VMA splitting
Prior to this commit, the gntdev driver code did not handle the
following scenario correctly with paravirtualized (PV) Xen domains:
* User process sets up a gntdev mapping composed of two grant mappings
(i.e., two pages shared by another Xen domain).
* User process munmap()s one of the pages.
* User process munmap()s the remaining page.
* User process exits.
In the scenario above, the user process would cause the kernel to log
the following messages in dmesg for the first munmap(), and the second
munmap() call would result in similar log messages:
BUG: Bad page map in process doublemap.test pte:... pmd:...
page:0000000057c97bff refcount:1 mapcount:-1 \
mapping:0000000000000000 index:0x0 pfn:...
...
page dumped because: bad pte
...
file:gntdev fault:0x0 mmap:gntdev_mmap [xen_gntdev] readpage:0x0
...
Call Trace:
<TASK>
dump_stack_lvl+0x46/0x5e
print_bad_pte.cold+0x66/0xb6
unmap_page_range+0x7e5/0xdc0
unmap_vmas+0x78/0xf0
unmap_region+0xa8/0x110
__do_munmap+0x1ea/0x4e0
__vm_munmap+0x75/0x120
__x64_sys_munmap+0x28/0x40
do_syscall_64+0x38/0x90
entry_SYSCALL_64_after_hwframe+0x61/0xcb
...
For each munmap() call, the Xen hypervisor (if built with CONFIG_DEBUG)
would print out the following and trigger a general protection fault in
the affected Xen PV domain:
(XEN) d0v... Attempt to implicitly unmap d0's grant PTE ...
(XEN) d0v... Attempt to implicitly unmap d0's grant PTE ...
As of this writing, gntdev_grant_map structure's vma field (referred to
as map->vma below) is mainly used for checking the start and end
addresses of mappings. However, with split VMAs, these may change, and
there could be more than one VMA associated with a gntdev mapping.
Hence, remove the use of map->vma and rely on map->pages_vm_start for
the original start address and on (map->count << PAGE_SHIFT) for the
original mapping size. Let the invalidate() and find_special_page()
hooks use these.
Also, given that there can be multiple VMAs associated with a gntdev
mapping, move the "mmu_interval_notifier_remove(&map->notifier)" call to
the end of gntdev_put_map, so that the MMU notifier is only removed
after the closing of the last remaining VMA.
Finally, use an atomic to prevent inadvertent gntdev mapping re-use,
instead of using the map->live_grants atomic counter and/or the map->vma
pointer (the latter of which is now removed). This prevents the
userspace from mmap()'ing (with MAP_FIXED) a gntdev mapping over the
same address range as a previously set up gntdev mapping. This scenario
can be summarized with the following call-trace, which was valid prior
to this commit:
mmap
gntdev_mmap
mmap (repeat mmap with MAP_FIXED over the same address range)
gntdev_invalidate
unmap_grant_pages (sets 'being_removed' entries to true)
gnttab_unmap_refs_async
unmap_single_vma
gntdev_mmap (maps the shared pages again)
munmap
gntdev_invalidate
unmap_grant_pages
(no-op because 'being_removed' entries are true)
unmap_single_vma (For PV domains, Xen reports that a granted page
is being unmapped and triggers a general protection fault in the
affected domain, if Xen was built with CONFIG_DEBUG)
The fix for this last scenario could be worth its own commit, but we
opted for a single commit, because removing the gntdev_grant_map
structure's vma field requires guarding the entry to gntdev_mmap(), and
the live_grants atomic counter is not sufficient on its own to prevent
the mmap() over a pre-existing mapping.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-10-04
In the Linux kernel, the following vulnerability has been resolved:
macintosh: fix possible memory leak in macio_add_one_device()
Afer commit 1fa5ae857bb1 ("driver core: get rid of struct device's
bus_id string array"), the name of device is allocated dynamically. It
needs to be freed when of_device_register() fails. Call put_device() to
give up the reference that's taken in device_initialize(), so that it
can be freed in kobject_cleanup() when the refcount hits 0.
macio device is freed in macio_release_dev(), so the kfree() can be
removed.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-10-04
In the Linux kernel, the following vulnerability has been resolved:
xhci: Remove device endpoints from bandwidth list when freeing the device
Endpoints are normally deleted from the bandwidth list when they are
dropped, before the virt device is freed.
If xHC host is dying or being removed then the endpoints aren't dropped
cleanly due to functions returning early to avoid interacting with a
non-accessible host controller.
So check and delete endpoints that are still on the bandwidth list when
freeing the virt device.
Solves a list_del corruption kernel crash when unbinding xhci-pci,
caused by xhci_mem_cleanup() when it later tried to delete already freed
endpoints from the bandwidth list.
This only affects hosts that use software bandwidth checking, which
currenty is only the xHC in intel Panther Point PCH (Ivy Bridge)
CVSS Score
7.8
EPSS Score
0.0
Published
2025-10-04
In the Linux kernel, the following vulnerability has been resolved:
cnic: Fix use-after-free bugs in cnic_delete_task
The original code uses cancel_delayed_work() in cnic_cm_stop_bnx2x_hw(),
which does not guarantee that the delayed work item 'delete_task' has
fully completed if it was already running. Additionally, the delayed work
item is cyclic, the flush_workqueue() in cnic_cm_stop_bnx2x_hw() only
blocks and waits for work items that were already queued to the
workqueue prior to its invocation. Any work items submitted after
flush_workqueue() is called are not included in the set of tasks that the
flush operation awaits. This means that after the cyclic work items have
finished executing, a delayed work item may still exist in the workqueue.
This leads to use-after-free scenarios where the cnic_dev is deallocated
by cnic_free_dev(), while delete_task remains active and attempt to
dereference cnic_dev in cnic_delete_task().
A typical race condition is illustrated below:
CPU 0 (cleanup) | CPU 1 (delayed work callback)
cnic_netdev_event() |
cnic_stop_hw() | cnic_delete_task()
cnic_cm_stop_bnx2x_hw() | ...
cancel_delayed_work() | /* the queue_delayed_work()
flush_workqueue() | executes after flush_workqueue()*/
| queue_delayed_work()
cnic_free_dev(dev)//free | cnic_delete_task() //new instance
| dev = cp->dev; //use
Replace cancel_delayed_work() with cancel_delayed_work_sync() to ensure
that the cyclic delayed work item is properly canceled and that any
ongoing execution of the work item completes before the cnic_dev is
deallocated. Furthermore, since cancel_delayed_work_sync() uses
__flush_work(work, true) to synchronously wait for any currently
executing instance of the work item to finish, the flush_workqueue()
becomes redundant and should be removed.
This bug was identified through static analysis. To reproduce the issue
and validate the fix, I simulated the cnic PCI device in QEMU and
introduced intentional delays — such as inserting calls to ssleep()
within the cnic_delete_task() function — to increase the likelihood
of triggering the bug.
CVSS Score
7.8
EPSS Score
0.0
Published
2025-10-04
In the Linux kernel, the following vulnerability has been resolved:
dm-stripe: fix a possible integer overflow
There's a possible integer overflow in stripe_io_hints if we have too
large chunk size. Test if the overflow happened, and if it did, don't set
limits->io_min and limits->io_opt;
CVSS Score
5.5
EPSS Score
0.0
Published
2025-10-04
In the Linux kernel, the following vulnerability has been resolved:
udf: Do not bother merging very long extents
When merging very long extents we try to push as much length as possible
to the first extent. However this is unnecessarily complicated and not
really worth the trouble. Furthermore there was a bug in the logic
resulting in corrupting extents in the file as syzbot reproducer shows.
So just don't bother with the merging of extents that are too long
together.
CVSS Score
7.8
EPSS Score
0.0
Published
2025-10-01
In the Linux kernel, the following vulnerability has been resolved:
xfrm: fix slab-use-after-free in decode_session6
When the xfrm device is set to the qdisc of the sfb type, the cb field
of the sent skb may be modified during enqueuing. Then,
slab-use-after-free may occur when the xfrm device sends IPv6 packets.
The stack information is as follows:
BUG: KASAN: slab-use-after-free in decode_session6+0x103f/0x1890
Read of size 1 at addr ffff8881111458ef by task swapper/3/0
CPU: 3 PID: 0 Comm: swapper/3 Not tainted 6.4.0-next-20230707 #409
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-1.fc33 04/01/2014
Call Trace:
<IRQ>
dump_stack_lvl+0xd9/0x150
print_address_description.constprop.0+0x2c/0x3c0
kasan_report+0x11d/0x130
decode_session6+0x103f/0x1890
__xfrm_decode_session+0x54/0xb0
xfrmi_xmit+0x173/0x1ca0
dev_hard_start_xmit+0x187/0x700
sch_direct_xmit+0x1a3/0xc30
__qdisc_run+0x510/0x17a0
__dev_queue_xmit+0x2215/0x3b10
neigh_connected_output+0x3c2/0x550
ip6_finish_output2+0x55a/0x1550
ip6_finish_output+0x6b9/0x1270
ip6_output+0x1f1/0x540
ndisc_send_skb+0xa63/0x1890
ndisc_send_rs+0x132/0x6f0
addrconf_rs_timer+0x3f1/0x870
call_timer_fn+0x1a0/0x580
expire_timers+0x29b/0x4b0
run_timer_softirq+0x326/0x910
__do_softirq+0x1d4/0x905
irq_exit_rcu+0xb7/0x120
sysvec_apic_timer_interrupt+0x97/0xc0
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x1a/0x20
RIP: 0010:intel_idle_hlt+0x23/0x30
Code: 1f 84 00 00 00 00 00 f3 0f 1e fa 41 54 41 89 d4 0f 1f 44 00 00 66 90 0f 1f 44 00 00 0f 00 2d c4 9f ab 00 0f 1f 44 00 00 fb f4 <fa> 44 89 e0 41 5c c3 66 0f 1f 44 00 00 f3 0f 1e fa 41 54 41 89 d4
RSP: 0018:ffffc90000197d78 EFLAGS: 00000246
RAX: 00000000000a83c3 RBX: ffffe8ffffd09c50 RCX: ffffffff8a22d8e5
RDX: 0000000000000001 RSI: ffffffff8d3f8080 RDI: ffffe8ffffd09c50
RBP: ffffffff8d3f8080 R08: 0000000000000001 R09: ffffed1026ba6d9d
R10: ffff888135d36ceb R11: 0000000000000001 R12: 0000000000000001
R13: ffffffff8d3f8100 R14: 0000000000000001 R15: 0000000000000000
cpuidle_enter_state+0xd3/0x6f0
cpuidle_enter+0x4e/0xa0
do_idle+0x2fe/0x3c0
cpu_startup_entry+0x18/0x20
start_secondary+0x200/0x290
secondary_startup_64_no_verify+0x167/0x16b
</TASK>
Allocated by task 939:
kasan_save_stack+0x22/0x40
kasan_set_track+0x25/0x30
__kasan_slab_alloc+0x7f/0x90
kmem_cache_alloc_node+0x1cd/0x410
kmalloc_reserve+0x165/0x270
__alloc_skb+0x129/0x330
inet6_ifa_notify+0x118/0x230
__ipv6_ifa_notify+0x177/0xbe0
addrconf_dad_completed+0x133/0xe00
addrconf_dad_work+0x764/0x1390
process_one_work+0xa32/0x16f0
worker_thread+0x67d/0x10c0
kthread+0x344/0x440
ret_from_fork+0x1f/0x30
The buggy address belongs to the object at ffff888111145800
which belongs to the cache skbuff_small_head of size 640
The buggy address is located 239 bytes inside of
freed 640-byte region [ffff888111145800, ffff888111145a80)
As commit f855691975bb ("xfrm6: Fix the nexthdr offset in
_decode_session6.") showed, xfrm_decode_session was originally intended
only for the receive path. IP6CB(skb)->nhoff is not set during
transmission. Therefore, set the cb field in the skb to 0 before
sending packets.
CVSS Score
7.8
EPSS Score
0.0
Published
2025-10-01
In the Linux kernel, the following vulnerability has been resolved:
start_kernel: Add __no_stack_protector function attribute
Back during the discussion of
commit a9a3ed1eff36 ("x86: Fix early boot crash on gcc-10, third try")
we discussed the need for a function attribute to control the omission
of stack protectors on a per-function basis; at the time Clang had
support for no_stack_protector but GCC did not. This was fixed in
gcc-11. Now that the function attribute is available, let's start using
it.
Callers of boot_init_stack_canary need to use this function attribute
unless they're compiled with -fno-stack-protector, otherwise the canary
stored in the stack slot of the caller will differ upon the call to
boot_init_stack_canary. This will lead to a call to __stack_chk_fail()
then panic.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-10-01
In the Linux kernel, the following vulnerability has been resolved:
lib: cpu_rmap: Avoid use after free on rmap->obj array entries
When calling irq_set_affinity_notifier() with NULL at the notify
argument, it will cause freeing of the glue pointer in the
corresponding array entry but will leave the pointer in the array. A
subsequent call to free_irq_cpu_rmap() will try to free this entry again
leading to possible use after free.
Fix that by setting NULL to the array entry and checking that we have
non-zero at the array entry when iterating over the array in
free_irq_cpu_rmap().
The current code does not suffer from this since there are no cases
where irq_set_affinity_notifier(irq, NULL) (note the NULL passed for the
notify arg) is called, followed by a call to free_irq_cpu_rmap() so we
don't hit and issue. Subsequent patches in this series excersize this
flow, hence the required fix.
CVSS Score
7.8
EPSS Score
0.0
Published
2025-10-01
In the Linux kernel, the following vulnerability has been resolved:
fs: jfs: Fix UBSAN: array-index-out-of-bounds in dbAllocDmapLev
Syzkaller reported the following issue:
UBSAN: array-index-out-of-bounds in fs/jfs/jfs_dmap.c:1965:6
index -84 is out of range for type 's8[341]' (aka 'signed char[341]')
CPU: 1 PID: 4995 Comm: syz-executor146 Not tainted 6.4.0-rc6-syzkaller-00037-gb6dad5178cea #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x1e7/0x2d0 lib/dump_stack.c:106
ubsan_epilogue lib/ubsan.c:217 [inline]
__ubsan_handle_out_of_bounds+0x11c/0x150 lib/ubsan.c:348
dbAllocDmapLev+0x3e5/0x430 fs/jfs/jfs_dmap.c:1965
dbAllocCtl+0x113/0x920 fs/jfs/jfs_dmap.c:1809
dbAllocAG+0x28f/0x10b0 fs/jfs/jfs_dmap.c:1350
dbAlloc+0x658/0xca0 fs/jfs/jfs_dmap.c:874
dtSplitUp fs/jfs/jfs_dtree.c:974 [inline]
dtInsert+0xda7/0x6b00 fs/jfs/jfs_dtree.c:863
jfs_create+0x7b6/0xbb0 fs/jfs/namei.c:137
lookup_open fs/namei.c:3492 [inline]
open_last_lookups fs/namei.c:3560 [inline]
path_openat+0x13df/0x3170 fs/namei.c:3788
do_filp_open+0x234/0x490 fs/namei.c:3818
do_sys_openat2+0x13f/0x500 fs/open.c:1356
do_sys_open fs/open.c:1372 [inline]
__do_sys_openat fs/open.c:1388 [inline]
__se_sys_openat fs/open.c:1383 [inline]
__x64_sys_openat+0x247/0x290 fs/open.c:1383
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f1f4e33f7e9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 51 14 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffc21129578 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f1f4e33f7e9
RDX: 000000000000275a RSI: 0000000020000040 RDI: 00000000ffffff9c
RBP: 00007f1f4e2ff080 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f1f4e2ff110
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
</TASK>
The bug occurs when the dbAllocDmapLev()function attempts to access
dp->tree.stree[leafidx + LEAFIND] while the leafidx value is negative.
To rectify this, the patch introduces a safeguard within the
dbAllocDmapLev() function. A check has been added to verify if leafidx is
negative. If it is, the function immediately returns an I/O error, preventing
any further execution that could potentially cause harm.
Tested via syzbot.
CVSS Score
7.8
EPSS Score
0.0
Published
2025-10-01