| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| In the Linux kernel, the following vulnerability has been resolved:
net/mlx5: fw_tracer, Validate format string parameters
Add validation for format string parameters in the firmware tracer to
prevent potential security vulnerabilities and crashes from malformed
format strings received from firmware.
The firmware tracer receives format strings from the device firmware and
uses them to format trace messages. Without proper validation, bad
firmware could provide format strings with invalid format specifiers
(e.g., %s, %p, %n) that could lead to crashes, or other undefined
behavior.
Add mlx5_tracer_validate_params() to validate that all format specifiers
in trace strings are limited to safe integer/hex formats (%x, %d, %i,
%u, %llx, %lx, etc.). Reject strings containing other format types that
could be used to access arbitrary memory or cause crashes.
Invalid format strings are added to the trace output for visibility with
"BAD_FORMAT: " prefix. |
| In the Linux kernel, the following vulnerability has been resolved:
scsi: target: Reset t_task_cdb pointer in error case
If allocation of cmd->t_task_cdb fails, it remains NULL but is later
dereferenced in the 'err' path.
In case of error, reset NULL t_task_cdb value to point at the default
fixed-size buffer.
Found by Linux Verification Center (linuxtesting.org) with SVACE. |
| In the Linux kernel, the following vulnerability has been resolved:
EDAC/versalnet: Fix device_node leak in mc_probe()
of_parse_phandle() returns a device_node reference that must be released with
of_node_put(). The original code never freed r5_core_node on any exit path,
causing a memory leak.
Fix this by using the automatic cleanup attribute __free(device_node) which
ensures of_node_put() is called when the variable goes out of scope. |
| In the Linux kernel, the following vulnerability has been resolved:
net: ks8851: Reinstate disabling of BHs around IRQ handler
If the driver executes ks8851_irq() AND a TX packet has been sent, then
the driver enables TX queue via netif_wake_queue() which schedules TX
softirq to queue packets for this device.
If CONFIG_PREEMPT_RT=y is set AND a packet has also been received by
the MAC, then ks8851_rx_pkts() calls netdev_alloc_skb_ip_align() to
allocate SKBs for the received packets. If netdev_alloc_skb_ip_align()
is called with BH enabled, then local_bh_enable() at the end of
netdev_alloc_skb_ip_align() will trigger the pending softirq processing,
which may ultimately call the .xmit callback ks8851_start_xmit_par().
The ks8851_start_xmit_par() will try to lock struct ks8851_net_par
.lock spinlock, which is already locked by ks8851_irq() from which
ks8851_start_xmit_par() was called. This leads to a deadlock, which
is reported by the kernel, including a trace listed below.
If CONFIG_PREEMPT_RT is not set, then since commit 0913ec336a6c0
("net: ks8851: Fix deadlock with the SPI chip variant") the deadlock
can also be triggered without received packet in the RX FIFO. The
pending softirqs will be processed on return from
spin_unlock_bh(&ks->statelock) in ks8851_irq(), which triggers the
deadlock as well.
Fix the problem by disabling BH around critical sections, including the
IRQ handler, thus preventing the net_tx_action() softirq from triggering
during these critical sections. The net_tx_action() softirq is triggered
once BH are re-enabled and at the end of the IRQ handler, once all the
other IRQ handler actions have been completed.
__schedule from schedule_rtlock+0x1c/0x34
schedule_rtlock from rtlock_slowlock_locked+0x548/0x904
rtlock_slowlock_locked from rt_spin_lock+0x60/0x9c
rt_spin_lock from ks8851_start_xmit_par+0x74/0x1a8
ks8851_start_xmit_par from netdev_start_xmit+0x20/0x44
netdev_start_xmit from dev_hard_start_xmit+0xd0/0x188
dev_hard_start_xmit from sch_direct_xmit+0xb8/0x25c
sch_direct_xmit from __qdisc_run+0x1f8/0x4ec
__qdisc_run from qdisc_run+0x1c/0x28
qdisc_run from net_tx_action+0x1f0/0x268
net_tx_action from handle_softirqs+0x1a4/0x270
handle_softirqs from __local_bh_enable_ip+0xcc/0xe0
__local_bh_enable_ip from __alloc_skb+0xd8/0x128
__alloc_skb from __netdev_alloc_skb+0x3c/0x19c
__netdev_alloc_skb from ks8851_irq+0x388/0x4d4
ks8851_irq from irq_thread_fn+0x24/0x64
irq_thread_fn from irq_thread+0x178/0x28c
irq_thread from kthread+0x12c/0x138
kthread from ret_from_fork+0x14/0x28 |
| In the Linux kernel, the following vulnerability has been resolved:
KVM: nSVM: Triple fault if restore host CR3 fails on nested #VMEXIT
If loading L1's CR3 fails on a nested #VMEXIT, nested_svm_vmexit()
returns an error code that is ignored by most callers, and continues to
run L1 with corrupted state. A sane recovery is not possible in this
case, and HW behavior is to cause a shutdown. Inject a triple fault
instead, and do not return early from nested_svm_vmexit(). Continue
cleaning up the vCPU state (e.g. clear pending exceptions), to handle
the failure as gracefully as possible.
From the APM:
Upon #VMEXIT, the processor performs the following actions in order to
return to the host execution context:
...
if (illegal host state loaded, or exception while loading host state)
shutdown
else
execute first host instruction following the VMRUN
Remove the return value of nested_svm_vmexit(), which is mostly
unchecked anyway. |
| In the Linux kernel, the following vulnerability has been resolved:
crypto: authencesn - reject short ahash digests during instance creation
authencesn requires either a zero authsize or an authsize of at least
4 bytes because the ESN encrypt/decrypt paths always move 4 bytes of
high-order sequence number data at the end of the authenticated data.
While crypto_authenc_esn_setauthsize() already rejects explicit
non-zero authsizes in the range 1..3, crypto_authenc_esn_create()
still copied auth->digestsize into inst->alg.maxauthsize without
validating it. The AEAD core then initialized the tfm's default
authsize from that value.
As a result, selecting an ahash with digest size 1..3, such as
cbcmac(cipher_null), exposed authencesn instances whose default
authsize was invalid even though setauthsize() would have rejected the
same value. AF_ALG could then trigger the ESN tail handling with a
too-short tag and hit an out-of-bounds access.
Reject authencesn instances whose ahash digest size is in the invalid
non-zero range 1..3 so that no tfm can inherit an unsupported default
authsize. |
| In the Linux kernel, the following vulnerability has been resolved:
vfio/cdx: Fix NULL pointer dereference in interrupt trigger path
Add validation to ensure MSI is configured before accessing cdx_irqs
array in vfio_cdx_set_msi_trigger(). Without this check, userspace
can trigger a NULL pointer dereference by calling VFIO_DEVICE_SET_IRQS
with VFIO_IRQ_SET_DATA_BOOL or VFIO_IRQ_SET_DATA_NONE flags before
ever setting up interrupts via VFIO_IRQ_SET_DATA_EVENTFD.
The vfio_cdx_msi_enable() function allocates the cdx_irqs array and
sets config_msi to 1 only when called through the EVENTFD path. The
trigger loop (for DATA_BOOL/DATA_NONE) assumed this had already been
done, but there was no enforcement of this call ordering.
This matches the protection used in the PCI VFIO driver where
vfio_pci_set_msi_trigger() checks irq_is() before the trigger loop. |
| In the Linux kernel, the following vulnerability has been resolved:
mm/page_alloc: return NULL early from alloc_frozen_pages_nolock() in NMI on UP
On UP kernels (!CONFIG_SMP), spin_trylock() is a no-op that
unconditionally succeeds even when the lock is already held. As a
result, alloc_frozen_pages_nolock() called from NMI context can
re-enter rmqueue() and acquire the zone lock that the interrupted
context is already holding, corrupting the freelists.
With CONFIG_DEBUG_SPINLOCK on UP, the following BUG is triggered with
the slub_kunit test module:
BUG: spinlock trylock failure on UP on CPU#0, kunit_try_catch/243
[...]
Call Trace:
<NMI>
dump_stack_lvl+0x3f/0x60
do_raw_spin_trylock+0x41/0x50
_raw_spin_trylock+0x24/0x50
rmqueue.isra.0+0x2a9/0xa70
get_page_from_freelist+0xeb/0x450
alloc_frozen_pages_nolock_noprof+0x111/0x1e0
allocate_slab+0x42a/0x500
___slab_alloc+0xa7/0x4c0
kmalloc_nolock_noprof+0x164/0x310
[...]
</NMI>
Fix this by returning NULL early when invoked from NMI on a UP kernel. |
| In the Linux kernel, the following vulnerability has been resolved:
ext4: refresh inline data size before write operations
The cached ei->i_inline_size can become stale between the initial size
check and when ext4_update_inline_data()/ext4_create_inline_data() use
it. Although ext4_get_max_inline_size() reads the correct value at the
time of the check, concurrent xattr operations can modify i_inline_size
before ext4_write_lock_xattr() is acquired.
This causes ext4_update_inline_data() and ext4_create_inline_data() to
work with stale capacity values, leading to a BUG_ON() crash in
ext4_write_inline_data():
kernel BUG at fs/ext4/inline.c:1331!
BUG_ON(pos + len > EXT4_I(inode)->i_inline_size);
The race window:
1. ext4_get_max_inline_size() reads i_inline_size = 60 (correct)
2. Size check passes for 50-byte write
3. [Another thread adds xattr, i_inline_size changes to 40]
4. ext4_write_lock_xattr() acquires lock
5. ext4_update_inline_data() uses stale i_inline_size = 60
6. Attempts to write 50 bytes but only 40 bytes actually available
7. BUG_ON() triggers
Fix this by recalculating i_inline_size via ext4_find_inline_data_nolock()
immediately after acquiring xattr_sem. This ensures ext4_update_inline_data()
and ext4_create_inline_data() work with current values that are protected
from concurrent modifications.
This is similar to commit a54c4613dac1 ("ext4: fix race writing to an
inline_data file while its xattrs are changing") which fixed i_inline_off
staleness. This patch addresses the related i_inline_size staleness issue. |
| In the Linux kernel, the following vulnerability has been resolved:
jbd2: avoid bug_on in jbd2_journal_get_create_access() when file system corrupted
There's issue when file system corrupted:
------------[ cut here ]------------
kernel BUG at fs/jbd2/transaction.c:1289!
Oops: invalid opcode: 0000 [#1] SMP KASAN PTI
CPU: 5 UID: 0 PID: 2031 Comm: mkdir Not tainted 6.18.0-rc1-next
RIP: 0010:jbd2_journal_get_create_access+0x3b6/0x4d0
RSP: 0018:ffff888117aafa30 EFLAGS: 00010202
RAX: 0000000000000000 RBX: ffff88811a86b000 RCX: ffffffff89a63534
RDX: 1ffff110200ec602 RSI: 0000000000000004 RDI: ffff888100763010
RBP: ffff888100763000 R08: 0000000000000001 R09: ffff888100763028
R10: 0000000000000003 R11: 0000000000000000 R12: 0000000000000000
R13: ffff88812c432000 R14: ffff88812c608000 R15: ffff888120bfc000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f91d6970c99 CR3: 00000001159c4000 CR4: 00000000000006f0
Call Trace:
<TASK>
__ext4_journal_get_create_access+0x42/0x170
ext4_getblk+0x319/0x6f0
ext4_bread+0x11/0x100
ext4_append+0x1e6/0x4a0
ext4_init_new_dir+0x145/0x1d0
ext4_mkdir+0x326/0x920
vfs_mkdir+0x45c/0x740
do_mkdirat+0x234/0x2f0
__x64_sys_mkdir+0xd6/0x120
do_syscall_64+0x5f/0xfa0
entry_SYSCALL_64_after_hwframe+0x76/0x7e
The above issue occurs with us in errors=continue mode when accompanied by
storage failures. There have been many inconsistencies in the file system
data.
In the case of file system data inconsistency, for example, if the block
bitmap of a referenced block is not set, it can lead to the situation where
a block being committed is allocated and used again. As a result, the
following condition will not be satisfied then trigger BUG_ON. Of course,
it is entirely possible to construct a problematic image that can trigger
this BUG_ON through specific operations. In fact, I have constructed such
an image and easily reproduced this issue.
Therefore, J_ASSERT() holds true only under ideal conditions, but it may
not necessarily be satisfied in exceptional scenarios. Using J_ASSERT()
directly in abnormal situations would cause the system to crash, which is
clearly not what we want. So here we directly trigger a JBD abort instead
of immediately invoking BUG_ON. |
| In the Linux kernel, the following vulnerability has been resolved:
ext4: xattr: fix null pointer deref in ext4_raw_inode()
If ext4_get_inode_loc() fails (e.g. if it returns -EFSCORRUPTED),
iloc.bh will remain set to NULL. Since ext4_xattr_inode_dec_ref_all()
lacks error checking, this will lead to a null pointer dereference
in ext4_raw_inode(), called right after ext4_get_inode_loc().
Found by Linux Verification Center (linuxtesting.org) with SVACE. |
| In the Linux kernel, the following vulnerability has been resolved:
smb: client: fix memory leak in cifs_construct_tcon()
When having a multiuser mount with domain= specified and using
cifscreds, cifs_set_cifscreds() will end up setting @ctx->domainname,
so it needs to be freed before leaving cifs_construct_tcon().
This fixes the following memory leak reported by kmemleak:
mount.cifs //srv/share /mnt -o domain=ZELDA,multiuser,...
su - testuser
cifscreds add -d ZELDA -u testuser
...
ls /mnt/1
...
umount /mnt
echo scan > /sys/kernel/debug/kmemleak
cat /sys/kernel/debug/kmemleak
unreferenced object 0xffff8881203c3f08 (size 8):
comm "ls", pid 5060, jiffies 4307222943
hex dump (first 8 bytes):
5a 45 4c 44 41 00 cc cc ZELDA...
backtrace (crc d109a8cf):
__kmalloc_node_track_caller_noprof+0x572/0x710
kstrdup+0x3a/0x70
cifs_sb_tlink+0x1209/0x1770 [cifs]
cifs_get_fattr+0xe1/0xf50 [cifs]
cifs_get_inode_info+0xb5/0x240 [cifs]
cifs_revalidate_dentry_attr+0x2d1/0x470 [cifs]
cifs_getattr+0x28e/0x450 [cifs]
vfs_getattr_nosec+0x126/0x180
vfs_statx+0xf6/0x220
do_statx+0xab/0x110
__x64_sys_statx+0xd5/0x130
do_syscall_64+0xbb/0x380
entry_SYSCALL_64_after_hwframe+0x77/0x7f |
| In the Linux kernel, the following vulnerability has been resolved:
ethtool: Avoid overflowing userspace buffer on stats query
The ethtool -S command operates across three ioctl calls:
ETHTOOL_GSSET_INFO for the size, ETHTOOL_GSTRINGS for the names, and
ETHTOOL_GSTATS for the values.
If the number of stats changes between these calls (e.g., due to device
reconfiguration), userspace's buffer allocation will be incorrect,
potentially leading to buffer overflow.
Drivers are generally expected to maintain stable stat counts, but some
drivers (e.g., mlx5, bnx2x, bna, ksz884x) use dynamic counters, making
this scenario possible.
Some drivers try to handle this internally:
- bnad_get_ethtool_stats() returns early in case stats.n_stats is not
equal to the driver's stats count.
- micrel/ksz884x also makes sure not to write anything beyond
stats.n_stats and overflow the buffer.
However, both use stats.n_stats which is already assigned with the value
returned from get_sset_count(), hence won't solve the issue described
here.
Change ethtool_get_strings(), ethtool_get_stats(),
ethtool_get_phy_stats() to not return anything in case of a mismatch
between userspace's size and get_sset_size(), to prevent buffer
overflow.
The returned n_stats value will be equal to zero, to reflect that
nothing has been returned.
This could result in one of two cases when using upstream ethtool,
depending on when the size change is detected:
1. When detected in ethtool_get_strings():
# ethtool -S eth2
no stats available
2. When detected in get stats, all stats will be reported as zero.
Both cases are presumably transient, and a subsequent ethtool call
should succeed.
Other than the overflow avoidance, these two cases are very evident (no
output/cleared stats), which is arguably better than presenting
incorrect/shifted stats.
I also considered returning an error instead of a "silent" response, but
that seems more destructive towards userspace apps.
Notes:
- This patch does not claim to fix the inherent race, it only makes sure
that we do not overflow the userspace buffer, and makes for a more
predictable behavior.
- RTNL lock is held during each ioctl, the race window exists between
the separate ioctl calls when the lock is released.
- Userspace ethtool always fills stats.n_stats, but it is likely that
these stats ioctls are implemented in other userspace applications
which might not fill it. The added code checks that it's not zero,
to prevent any regressions. |
| In the Linux kernel, the following vulnerability has been resolved:
NFS: Automounted filesystems should inherit ro,noexec,nodev,sync flags
When a filesystem is being automounted, it needs to preserve the
user-set superblock mount options, such as the "ro" flag. |
| In the Linux kernel, the following vulnerability has been resolved:
mlxsw: spectrum_mr: Fix use-after-free when updating multicast route stats
Cited commit added a dedicated mutex (instead of RTNL) to protect the
multicast route list, so that it will not change while the driver
periodically traverses it in order to update the kernel about multicast
route stats that were queried from the device.
One instance of list entry deletion (during route replace) was missed
and it can result in a use-after-free [1].
Fix by acquiring the mutex before deleting the entry from the list and
releasing it afterwards.
[1]
BUG: KASAN: slab-use-after-free in mlxsw_sp_mr_stats_update+0x4a5/0x540 drivers/net/ethernet/mellanox/mlxsw/spectrum_mr.c:1006 [mlxsw_spectrum]
Read of size 8 at addr ffff8881523c2fa8 by task kworker/2:5/22043
CPU: 2 UID: 0 PID: 22043 Comm: kworker/2:5 Not tainted 6.18.0-rc1-custom-g1a3d6d7cd014 #1 PREEMPT(full)
Hardware name: Mellanox Technologies Ltd. MSN2010/SA002610, BIOS 5.6.5 08/24/2017
Workqueue: mlxsw_core mlxsw_sp_mr_stats_update [mlxsw_spectrum]
Call Trace:
<TASK>
dump_stack_lvl+0xba/0x110
print_report+0x174/0x4f5
kasan_report+0xdf/0x110
mlxsw_sp_mr_stats_update+0x4a5/0x540 drivers/net/ethernet/mellanox/mlxsw/spectrum_mr.c:1006 [mlxsw_spectrum]
process_one_work+0x9cc/0x18e0
worker_thread+0x5df/0xe40
kthread+0x3b8/0x730
ret_from_fork+0x3e9/0x560
ret_from_fork_asm+0x1a/0x30
</TASK>
Allocated by task 29933:
kasan_save_stack+0x30/0x50
kasan_save_track+0x14/0x30
__kasan_kmalloc+0x8f/0xa0
mlxsw_sp_mr_route_add+0xd8/0x4770 [mlxsw_spectrum]
mlxsw_sp_router_fibmr_event_work+0x371/0xad0 drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c:7965 [mlxsw_spectrum]
process_one_work+0x9cc/0x18e0
worker_thread+0x5df/0xe40
kthread+0x3b8/0x730
ret_from_fork+0x3e9/0x560
ret_from_fork_asm+0x1a/0x30
Freed by task 29933:
kasan_save_stack+0x30/0x50
kasan_save_track+0x14/0x30
__kasan_save_free_info+0x3b/0x70
__kasan_slab_free+0x43/0x70
kfree+0x14e/0x700
mlxsw_sp_mr_route_add+0x2dea/0x4770 drivers/net/ethernet/mellanox/mlxsw/spectrum_mr.c:444 [mlxsw_spectrum]
mlxsw_sp_router_fibmr_event_work+0x371/0xad0 drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c:7965 [mlxsw_spectrum]
process_one_work+0x9cc/0x18e0
worker_thread+0x5df/0xe40
kthread+0x3b8/0x730
ret_from_fork+0x3e9/0x560
ret_from_fork_asm+0x1a/0x30 |
| In the Linux kernel, the following vulnerability has been resolved:
svcrdma: use rc_pageoff for memcpy byte offset
svc_rdma_copy_inline_range added rc_curpage (page index) to the page
base instead of the byte offset rc_pageoff. Use rc_pageoff so copies
land within the current page.
Found by ZeroPath (https://zeropath.com) |
| In the Linux kernel, the following vulnerability has been resolved:
usbnet: Prevents free active kevent
The root cause of this issue are:
1. When probing the usbnet device, executing usbnet_link_change(dev, 0, 0);
put the kevent work in global workqueue. However, the kevent has not yet
been scheduled when the usbnet device is unregistered. Therefore, executing
free_netdev() results in the "free active object (kevent)" error reported
here.
2. Another factor is that when calling usbnet_disconnect()->unregister_netdev(),
if the usbnet device is up, ndo_stop() is executed to cancel the kevent.
However, because the device is not up, ndo_stop() is not executed.
The solution to this problem is to cancel the kevent before executing
free_netdev(). |
| In the Linux kernel, the following vulnerability has been resolved:
ext4: add i_data_sem protection in ext4_destroy_inline_data_nolock()
Fix a race between inline data destruction and block mapping.
The function ext4_destroy_inline_data_nolock() changes the inode data
layout by clearing EXT4_INODE_INLINE_DATA and setting EXT4_INODE_EXTENTS.
At the same time, another thread may execute ext4_map_blocks(), which
tests EXT4_INODE_EXTENTS to decide whether to call ext4_ext_map_blocks()
or ext4_ind_map_blocks().
Without i_data_sem protection, ext4_ind_map_blocks() may receive inode
with EXT4_INODE_EXTENTS flag and triggering assert.
kernel BUG at fs/ext4/indirect.c:546!
EXT4-fs (loop2): unmounting filesystem.
invalid opcode: 0000 [#1] PREEMPT SMP KASAN NOPTI
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014
RIP: 0010:ext4_ind_map_blocks.cold+0x2b/0x5a fs/ext4/indirect.c:546
Call Trace:
<TASK>
ext4_map_blocks+0xb9b/0x16f0 fs/ext4/inode.c:681
_ext4_get_block+0x242/0x590 fs/ext4/inode.c:822
ext4_block_write_begin+0x48b/0x12c0 fs/ext4/inode.c:1124
ext4_write_begin+0x598/0xef0 fs/ext4/inode.c:1255
ext4_da_write_begin+0x21e/0x9c0 fs/ext4/inode.c:3000
generic_perform_write+0x259/0x5d0 mm/filemap.c:3846
ext4_buffered_write_iter+0x15b/0x470 fs/ext4/file.c:285
ext4_file_write_iter+0x8e0/0x17f0 fs/ext4/file.c:679
call_write_iter include/linux/fs.h:2271 [inline]
do_iter_readv_writev+0x212/0x3c0 fs/read_write.c:735
do_iter_write+0x186/0x710 fs/read_write.c:861
vfs_iter_write+0x70/0xa0 fs/read_write.c:902
iter_file_splice_write+0x73b/0xc90 fs/splice.c:685
do_splice_from fs/splice.c:763 [inline]
direct_splice_actor+0x10f/0x170 fs/splice.c:950
splice_direct_to_actor+0x33a/0xa10 fs/splice.c:896
do_splice_direct+0x1a9/0x280 fs/splice.c:1002
do_sendfile+0xb13/0x12c0 fs/read_write.c:1255
__do_sys_sendfile64 fs/read_write.c:1323 [inline]
__se_sys_sendfile64 fs/read_write.c:1309 [inline]
__x64_sys_sendfile64+0x1cf/0x210 fs/read_write.c:1309
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x35/0x80 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x6e/0xd8 |
| In the Linux kernel, the following vulnerability has been resolved:
ipv4: route: Prevent rt_bind_exception() from rebinding stale fnhe
The sit driver's packet transmission path calls: sit_tunnel_xmit() ->
update_or_create_fnhe(), which lead to fnhe_remove_oldest() being called
to delete entries exceeding FNHE_RECLAIM_DEPTH+random.
The race window is between fnhe_remove_oldest() selecting fnheX for
deletion and the subsequent kfree_rcu(). During this time, the
concurrent path's __mkroute_output() -> find_exception() can fetch the
soon-to-be-deleted fnheX, and rt_bind_exception() then binds it with a
new dst using a dst_hold(). When the original fnheX is freed via RCU,
the dst reference remains permanently leaked.
CPU 0 CPU 1
__mkroute_output()
find_exception() [fnheX]
update_or_create_fnhe()
fnhe_remove_oldest() [fnheX]
rt_bind_exception() [bind dst]
RCU callback [fnheX freed, dst leak]
This issue manifests as a device reference count leak and a warning in
dmesg when unregistering the net device:
unregister_netdevice: waiting for sitX to become free. Usage count = N
Ido Schimmel provided the simple test validation method [1].
The fix clears 'oldest->fnhe_daddr' before calling fnhe_flush_routes().
Since rt_bind_exception() checks this field, setting it to zero prevents
the stale fnhe from being reused and bound to a new dst just before it
is freed.
[1]
ip netns add ns1
ip -n ns1 link set dev lo up
ip -n ns1 address add 192.0.2.1/32 dev lo
ip -n ns1 link add name dummy1 up type dummy
ip -n ns1 route add 192.0.2.2/32 dev dummy1
ip -n ns1 link add name gretap1 up arp off type gretap \
local 192.0.2.1 remote 192.0.2.2
ip -n ns1 route add 198.51.0.0/16 dev gretap1
taskset -c 0 ip netns exec ns1 mausezahn gretap1 \
-A 198.51.100.1 -B 198.51.0.0/16 -t udp -p 1000 -c 0 -q &
taskset -c 2 ip netns exec ns1 mausezahn gretap1 \
-A 198.51.100.1 -B 198.51.0.0/16 -t udp -p 1000 -c 0 -q &
sleep 10
ip netns pids ns1 | xargs kill
ip netns del ns1 |
| In the Linux kernel, the following vulnerability has been resolved:
fsnotify: do not generate ACCESS/MODIFY events on child for special files
inotify/fanotify do not allow users with no read access to a file to
subscribe to events (e.g. IN_ACCESS/IN_MODIFY), but they do allow the
same user to subscribe for watching events on children when the user
has access to the parent directory (e.g. /dev).
Users with no read access to a file but with read access to its parent
directory can still stat the file and see if it was accessed/modified
via atime/mtime change.
The same is not true for special files (e.g. /dev/null). Users will not
generally observe atime/mtime changes when other users read/write to
special files, only when someone sets atime/mtime via utimensat().
Align fsnotify events with this stat behavior and do not generate
ACCESS/MODIFY events to parent watchers on read/write of special files.
The events are still generated to parent watchers on utimensat(). This
closes some side-channels that could be possibly used for information
exfiltration [1].
[1] https://snee.la/pdf/pubs/file-notification-attacks.pdf |
