| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| In the Linux kernel, the following vulnerability has been resolved:
nilfs2: fix infinite loop in nilfs_mdt_get_block()
If the disk image that nilfs2 mounts is corrupted and a virtual block
address obtained by block lookup for a metadata file is invalid,
nilfs_bmap_lookup_at_level() may return the same internal return code as
-ENOENT, meaning the block does not exist in the metadata file.
This duplication of return codes confuses nilfs_mdt_get_block(), causing
it to read and create a metadata block indefinitely.
In particular, if this happens to the inode metadata file, ifile,
semaphore i_rwsem can be left held, causing task hangs in lock_mount.
Fix this issue by making nilfs_bmap_lookup_at_level() treat virtual block
address translation failures with -ENOENT as metadata corruption instead
of returning the error code. |
| In the Linux kernel, the following vulnerability has been resolved:
md/raid5-cache: fix a deadlock in r5l_exit_log()
Commit b13015af94cf ("md/raid5-cache: Clear conf->log after finishing
work") introduce a new problem:
// caller hold reconfig_mutex
r5l_exit_log
flush_work(&log->disable_writeback_work)
r5c_disable_writeback_async
wait_event
/*
* conf->log is not NULL, and mddev_trylock()
* will fail, wait_event() can never pass.
*/
conf->log = NULL
Fix this problem by setting 'config->log' to NULL before wake_up() as it
used to be, so that wait_event() from r5c_disable_writeback_async() can
exist. In the meantime, move forward md_unregister_thread() so that
null-ptr-deref this commit fixed can still be fixed. |
| In the Linux kernel, the following vulnerability has been resolved:
iavf: use internal state to free traffic IRQs
If the system tries to close the netdev while iavf_reset_task() is
running, __LINK_STATE_START will be cleared and netif_running() will
return false in iavf_reinit_interrupt_scheme(). This will result in
iavf_free_traffic_irqs() not being called and a leak as follows:
[7632.489326] remove_proc_entry: removing non-empty directory 'irq/999', leaking at least 'iavf-enp24s0f0v0-TxRx-0'
[7632.490214] WARNING: CPU: 0 PID: 10 at fs/proc/generic.c:718 remove_proc_entry+0x19b/0x1b0
is shown when pci_disable_msix() is later called. Fix by using the
internal adapter state. The traffic IRQs will always exist if
state == __IAVF_RUNNING. |
| In the Linux kernel, the following vulnerability has been resolved:
nvme-core: fix memory leak in dhchap_secret_store
Free dhchap_secret in nvme_ctrl_dhchap_secret_store() before we return
fix following kmemleack:-
unreferenced object 0xffff8886376ea800 (size 64):
comm "check", pid 22048, jiffies 4344316705 (age 92.199s)
hex dump (first 32 bytes):
44 48 48 43 2d 31 3a 30 30 3a 6e 78 72 35 4b 67 DHHC-1:00:nxr5Kg
75 58 34 75 6f 41 78 73 4a 61 34 63 2f 68 75 4c uX4uoAxsJa4c/huL
backtrace:
[<0000000030ce5d4b>] __kmalloc+0x4b/0x130
[<000000009be1cdc1>] nvme_ctrl_dhchap_secret_store+0x8f/0x160 [nvme_core]
[<00000000ac06c96a>] kernfs_fop_write_iter+0x12b/0x1c0
[<00000000437e7ced>] vfs_write+0x2ba/0x3c0
[<00000000f9491baf>] ksys_write+0x5f/0xe0
[<000000001c46513d>] do_syscall_64+0x3b/0x90
[<00000000ecf348fe>] entry_SYSCALL_64_after_hwframe+0x72/0xdc
unreferenced object 0xffff8886376eaf00 (size 64):
comm "check", pid 22048, jiffies 4344316736 (age 92.168s)
hex dump (first 32 bytes):
44 48 48 43 2d 31 3a 30 30 3a 6e 78 72 35 4b 67 DHHC-1:00:nxr5Kg
75 58 34 75 6f 41 78 73 4a 61 34 63 2f 68 75 4c uX4uoAxsJa4c/huL
backtrace:
[<0000000030ce5d4b>] __kmalloc+0x4b/0x130
[<000000009be1cdc1>] nvme_ctrl_dhchap_secret_store+0x8f/0x160 [nvme_core]
[<00000000ac06c96a>] kernfs_fop_write_iter+0x12b/0x1c0
[<00000000437e7ced>] vfs_write+0x2ba/0x3c0
[<00000000f9491baf>] ksys_write+0x5f/0xe0
[<000000001c46513d>] do_syscall_64+0x3b/0x90
[<00000000ecf348fe>] entry_SYSCALL_64_after_hwframe+0x72/0xdc |
| In the Linux kernel, the following vulnerability has been resolved:
ASoC: mediatek: mt8186: Fix use-after-free in driver remove path
When devm runs function in the "remove" path for a device it runs them
in the reverse order. That means that if you have parts of your driver
that aren't using devm or are using "roll your own" devm w/
devm_add_action_or_reset() you need to keep that in mind.
The mt8186 audio driver didn't quite get this right. Specifically, in
mt8186_init_clock() it called mt8186_audsys_clk_register() and then
went on to call a bunch of other devm function. The caller of
mt8186_init_clock() used devm_add_action_or_reset() to call
mt8186_deinit_clock() but, because of the intervening devm functions,
the order was wrong.
Specifically at probe time, the order was:
1. mt8186_audsys_clk_register()
2. afe_priv->clk = devm_kcalloc(...)
3. afe_priv->clk[i] = devm_clk_get(...)
At remove time, the order (which should have been 3, 2, 1) was:
1. mt8186_audsys_clk_unregister()
3. Free all of afe_priv->clk[i]
2. Free afe_priv->clk
The above seemed to be causing a use-after-free. Luckily, it's easy to
fix this by simply using devm more correctly. Let's move the
devm_add_action_or_reset() to the right place. In addition to fixing
the use-after-free, code inspection shows that this fixes a leak
(missing call to mt8186_audsys_clk_unregister()) that would have
happened if any of the syscon_regmap_lookup_by_phandle() calls in
mt8186_init_clock() had failed. |
| In the Linux kernel, the following vulnerability has been resolved:
tty: serial: samsung_tty: Fix a memory leak in s3c24xx_serial_getclk() in case of error
If clk_get_rate() fails, the clk that has just been allocated needs to be
freed. |
| In the Linux kernel, the following vulnerability has been resolved:
blk-mq: check kobject state_in_sysfs before deleting in blk_mq_unregister_hctx
In __blk_mq_update_nr_hw_queues() the return value of
blk_mq_sysfs_register_hctxs() is not checked. If sysfs creation for hctx
fails, later changing the number of hw_queues or removing disk will
trigger the following warning:
kernfs: can not remove 'nr_tags', no directory
WARNING: CPU: 2 PID: 637 at fs/kernfs/dir.c:1707 kernfs_remove_by_name_ns+0x13f/0x160
Call Trace:
remove_files.isra.1+0x38/0xb0
sysfs_remove_group+0x4d/0x100
sysfs_remove_groups+0x31/0x60
__kobject_del+0x23/0xf0
kobject_del+0x17/0x40
blk_mq_unregister_hctx+0x5d/0x80
blk_mq_sysfs_unregister_hctxs+0x94/0xd0
blk_mq_update_nr_hw_queues+0x124/0x760
nullb_update_nr_hw_queues+0x71/0xf0 [null_blk]
nullb_device_submit_queues_store+0x92/0x120 [null_blk]
kobjct_del() was called unconditionally even if sysfs creation failed.
Fix it by checkig the kobject creation statusbefore deleting it. |
| In the Linux kernel, the following vulnerability has been resolved:
crypto: essiv - Check ssize for decryption and in-place encryption
Move the ssize check to the start in essiv_aead_crypt so that
it's also checked for decryption and in-place encryption. |
| In the Linux kernel, the following vulnerability has been resolved:
media: b2c2: Fix use-after-free causing by irq_check_work in flexcop_pci_remove
The original code uses cancel_delayed_work() in flexcop_pci_remove(), which
does not guarantee that the delayed work item irq_check_work has fully
completed if it was already running. This leads to use-after-free scenarios
where flexcop_pci_remove() may free the flexcop_device while irq_check_work
is still active and attempts to dereference the device.
A typical race condition is illustrated below:
CPU 0 (remove) | CPU 1 (delayed work callback)
flexcop_pci_remove() | flexcop_pci_irq_check_work()
cancel_delayed_work() |
flexcop_device_kfree(fc_pci->fc_dev) |
| fc = fc_pci->fc_dev; // UAF
This is confirmed by a KASAN report:
==================================================================
BUG: KASAN: slab-use-after-free in __run_timer_base.part.0+0x7d7/0x8c0
Write of size 8 at addr ffff8880093aa8c8 by task bash/135
...
Call Trace:
<IRQ>
dump_stack_lvl+0x55/0x70
print_report+0xcf/0x610
? __run_timer_base.part.0+0x7d7/0x8c0
kasan_report+0xb8/0xf0
? __run_timer_base.part.0+0x7d7/0x8c0
__run_timer_base.part.0+0x7d7/0x8c0
? __pfx___run_timer_base.part.0+0x10/0x10
? __pfx_read_tsc+0x10/0x10
? ktime_get+0x60/0x140
? lapic_next_event+0x11/0x20
? clockevents_program_event+0x1d4/0x2a0
run_timer_softirq+0xd1/0x190
handle_softirqs+0x16a/0x550
irq_exit_rcu+0xaf/0xe0
sysvec_apic_timer_interrupt+0x70/0x80
</IRQ>
...
Allocated by task 1:
kasan_save_stack+0x24/0x50
kasan_save_track+0x14/0x30
__kasan_kmalloc+0x7f/0x90
__kmalloc_noprof+0x1be/0x460
flexcop_device_kmalloc+0x54/0xe0
flexcop_pci_probe+0x1f/0x9d0
local_pci_probe+0xdc/0x190
pci_device_probe+0x2fe/0x470
really_probe+0x1ca/0x5c0
__driver_probe_device+0x248/0x310
driver_probe_device+0x44/0x120
__driver_attach+0xd2/0x310
bus_for_each_dev+0xed/0x170
bus_add_driver+0x208/0x500
driver_register+0x132/0x460
do_one_initcall+0x89/0x300
kernel_init_freeable+0x40d/0x720
kernel_init+0x1a/0x150
ret_from_fork+0x10c/0x1a0
ret_from_fork_asm+0x1a/0x30
Freed by task 135:
kasan_save_stack+0x24/0x50
kasan_save_track+0x14/0x30
kasan_save_free_info+0x3a/0x60
__kasan_slab_free+0x3f/0x50
kfree+0x137/0x370
flexcop_device_kfree+0x32/0x50
pci_device_remove+0xa6/0x1d0
device_release_driver_internal+0xf8/0x210
pci_stop_bus_device+0x105/0x150
pci_stop_and_remove_bus_device_locked+0x15/0x30
remove_store+0xcc/0xe0
kernfs_fop_write_iter+0x2c3/0x440
vfs_write+0x871/0xd70
ksys_write+0xee/0x1c0
do_syscall_64+0xac/0x280
entry_SYSCALL_64_after_hwframe+0x77/0x7f
...
Replace cancel_delayed_work() with cancel_delayed_work_sync() to ensure
that the delayed work item is properly canceled and any executing delayed
work has finished before the device memory is deallocated.
This bug was initially identified through static analysis. To reproduce
and test it, I simulated the B2C2 FlexCop PCI device in QEMU and introduced
artificial delays within the flexcop_pci_irq_check_work() function to
increase the likelihood of triggering the bug. |
| In the Linux kernel, the following vulnerability has been resolved:
mm/memfd: fix information leak in hugetlb folios
When allocating hugetlb folios for memfd, three initialization steps are
missing:
1. Folios are not zeroed, leading to kernel memory disclosure to userspace
2. Folios are not marked uptodate before adding to page cache
3. hugetlb_fault_mutex is not taken before hugetlb_add_to_page_cache()
The memfd allocation path bypasses the normal page fault handler
(hugetlb_no_page) which would handle all of these initialization steps.
This is problematic especially for udmabuf use cases where folios are
pinned and directly accessed by userspace via DMA.
Fix by matching the initialization pattern used in hugetlb_no_page():
- Zero the folio using folio_zero_user() which is optimized for huge pages
- Mark it uptodate with folio_mark_uptodate()
- Take hugetlb_fault_mutex before adding to page cache to prevent races
The folio_zero_user() change also fixes a potential security issue where
uninitialized kernel memory could be disclosed to userspace through read()
or mmap() operations on the memfd. |
| In the Linux kernel, the following vulnerability has been resolved:
vmw_balloon: indicate success when effectively deflating during migration
When migrating a balloon page, we first deflate the old page to then
inflate the new page.
However, if inflating the new page succeeded, we effectively deflated the
old page, reducing the balloon size.
In that case, the migration actually worked: similar to migrating+
immediately deflating the new page. The old page will be freed back to
the buddy.
Right now, the core will leave the page be marked as isolated (as we
returned an error). When later trying to putback that page, we will run
into the WARN_ON_ONCE() in balloon_page_putback().
That handling was changed in commit 3544c4faccb8 ("mm/balloon_compaction:
stop using __ClearPageMovable()"); before that change, we would have
tolerated that way of handling it.
To fix it, let's just return 0 in that case, making the core effectively
just clear the "isolated" flag + freeing it back to the buddy as if the
migration succeeded. Note that the new page will also get freed when the
core puts the last reference.
Note that this also makes it all be more consistent: we will no longer
unisolate the page in the balloon driver while keeping it marked as being
isolated in migration core.
This was found by code inspection. |
| In the Linux kernel, the following vulnerability has been resolved:
net: netpoll: fix incorrect refcount handling causing incorrect cleanup
commit efa95b01da18 ("netpoll: fix use after free") incorrectly
ignored the refcount and prematurely set dev->npinfo to NULL during
netpoll cleanup, leading to improper behavior and memory leaks.
Scenario causing lack of proper cleanup:
1) A netpoll is associated with a NIC (e.g., eth0) and netdev->npinfo is
allocated, and refcnt = 1
- Keep in mind that npinfo is shared among all netpoll instances. In
this case, there is just one.
2) Another netpoll is also associated with the same NIC and
npinfo->refcnt += 1.
- Now dev->npinfo->refcnt = 2;
- There is just one npinfo associated to the netdev.
3) When the first netpolls goes to clean up:
- The first cleanup succeeds and clears np->dev->npinfo, ignoring
refcnt.
- It basically calls `RCU_INIT_POINTER(np->dev->npinfo, NULL);`
- Set dev->npinfo = NULL, without proper cleanup
- No ->ndo_netpoll_cleanup() is either called
4) Now the second target tries to clean up
- The second cleanup fails because np->dev->npinfo is already NULL.
* In this case, ops->ndo_netpoll_cleanup() was never called, and
the skb pool is not cleaned as well (for the second netpoll
instance)
- This leaks npinfo and skbpool skbs, which is clearly reported by
kmemleak.
Revert commit efa95b01da18 ("netpoll: fix use after free") and adds
clarifying comments emphasizing that npinfo cleanup should only happen
once the refcount reaches zero, ensuring stable and correct netpoll
behavior. |
| In the Linux kernel, the following vulnerability has been resolved:
mptcp: Fix proto fallback detection with BPF
The sockmap feature allows bpf syscall from userspace, or based
on bpf sockops, replacing the sk_prot of sockets during protocol stack
processing with sockmap's custom read/write interfaces.
'''
tcp_rcv_state_process()
syn_recv_sock()/subflow_syn_recv_sock()
tcp_init_transfer(BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB)
bpf_skops_established <== sockops
bpf_sock_map_update(sk) <== call bpf helper
tcp_bpf_update_proto() <== update sk_prot
'''
When the server has MPTCP enabled but the client sends a TCP SYN
without MPTCP, subflow_syn_recv_sock() performs a fallback on the
subflow, replacing the subflow sk's sk_prot with the native sk_prot.
'''
subflow_syn_recv_sock()
subflow_ulp_fallback()
subflow_drop_ctx()
mptcp_subflow_ops_undo_override()
'''
Then, this subflow can be normally used by sockmap, which replaces the
native sk_prot with sockmap's custom sk_prot. The issue occurs when the
user executes accept::mptcp_stream_accept::mptcp_fallback_tcp_ops().
Here, it uses sk->sk_prot to compare with the native sk_prot, but this
is incorrect when sockmap is used, as we may incorrectly set
sk->sk_socket->ops.
This fix uses the more generic sk_family for the comparison instead.
Additionally, this also prevents a WARNING from occurring:
result from ./scripts/decode_stacktrace.sh:
------------[ cut here ]------------
WARNING: CPU: 0 PID: 337 at net/mptcp/protocol.c:68 mptcp_stream_accept \
(net/mptcp/protocol.c:4005)
Modules linked in:
...
PKRU: 55555554
Call Trace:
<TASK>
do_accept (net/socket.c:1989)
__sys_accept4 (net/socket.c:2028 net/socket.c:2057)
__x64_sys_accept (net/socket.c:2067)
x64_sys_call (arch/x86/entry/syscall_64.c:41)
do_syscall_64 (arch/x86/entry/syscall_64.c:63 arch/x86/entry/syscall_64.c:94)
entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)
RIP: 0033:0x7f87ac92b83d
---[ end trace 0000000000000000 ]--- |
| In the Linux kernel, the following vulnerability has been resolved:
net: ethernet: ti: netcp: Standardize knav_dma_open_channel to return NULL on error
Make knav_dma_open_channel consistently return NULL on error instead
of ERR_PTR. Currently the header include/linux/soc/ti/knav_dma.h
returns NULL when the driver is disabled, but the driver
implementation does not even return NULL or ERR_PTR on failure,
causing inconsistency in the users. This results in a crash in
netcp_free_navigator_resources as followed (trimmed):
Unhandled fault: alignment exception (0x221) at 0xfffffff2
[fffffff2] *pgd=80000800207003, *pmd=82ffda003, *pte=00000000
Internal error: : 221 [#1] SMP ARM
Modules linked in:
CPU: 0 UID: 0 PID: 1 Comm: swapper/0 Not tainted 6.17.0-rc7 #1 NONE
Hardware name: Keystone
PC is at knav_dma_close_channel+0x30/0x19c
LR is at netcp_free_navigator_resources+0x2c/0x28c
[... TRIM...]
Call trace:
knav_dma_close_channel from netcp_free_navigator_resources+0x2c/0x28c
netcp_free_navigator_resources from netcp_ndo_open+0x430/0x46c
netcp_ndo_open from __dev_open+0x114/0x29c
__dev_open from __dev_change_flags+0x190/0x208
__dev_change_flags from netif_change_flags+0x1c/0x58
netif_change_flags from dev_change_flags+0x38/0xa0
dev_change_flags from ip_auto_config+0x2c4/0x11f0
ip_auto_config from do_one_initcall+0x58/0x200
do_one_initcall from kernel_init_freeable+0x1cc/0x238
kernel_init_freeable from kernel_init+0x1c/0x12c
kernel_init from ret_from_fork+0x14/0x38
[... TRIM...]
Standardize the error handling by making the function return NULL on
all error conditions. The API is used in just the netcp_core.c so the
impact is limited.
Note, this change, in effect reverts commit 5b6cb43b4d62 ("net:
ethernet: ti: netcp_core: return error while dma channel open issue"),
but provides a less error prone implementation. |
| In the Linux kernel, the following vulnerability has been resolved:
LoongArch: BPF: Disable trampoline for kernel module function trace
The current LoongArch BPF trampoline implementation is incompatible
with tracing functions in kernel modules. This causes several severe
and user-visible problems:
* The `bpf_selftests/module_attach` test fails consistently.
* Kernel lockup when a BPF program is attached to a module function [1].
* Critical kernel modules like WireGuard experience traffic disruption
when their functions are traced with fentry [2].
Given the severity and the potential for other unknown side-effects, it
is safest to disable the feature entirely for now. This patch prevents
the BPF subsystem from allowing trampoline attachments to kernel module
functions on LoongArch.
This is a temporary mitigation until the core issues in the trampoline
code for kernel module handling can be identified and fixed.
[root@fedora bpf]# ./test_progs -a module_attach -v
bpf_testmod.ko is already unloaded.
Loading bpf_testmod.ko...
Successfully loaded bpf_testmod.ko.
test_module_attach:PASS:skel_open 0 nsec
test_module_attach:PASS:set_attach_target 0 nsec
test_module_attach:PASS:set_attach_target_explicit 0 nsec
test_module_attach:PASS:skel_load 0 nsec
libbpf: prog 'handle_fentry': failed to attach: -ENOTSUPP
libbpf: prog 'handle_fentry': failed to auto-attach: -ENOTSUPP
test_module_attach:FAIL:skel_attach skeleton attach failed: -524
Summary: 0/0 PASSED, 0 SKIPPED, 1 FAILED
Successfully unloaded bpf_testmod.ko.
[1]: https://lore.kernel.org/loongarch/CAK3+h2wDmpC-hP4u4pJY8T-yfKyk4yRzpu2LMO+C13FMT58oqQ@mail.gmail.com/
[2]: https://lore.kernel.org/loongarch/CAK3+h2wYcpc+OwdLDUBvg2rF9rvvyc5amfHT-KcFaK93uoELPg@mail.gmail.com/ |
| In the Linux kernel, the following vulnerability has been resolved:
idpf: fix possible vport_config NULL pointer deref in remove
Attempting to remove the driver will cause a crash in cases where
the vport failed to initialize. Following trace is from an instance where
the driver failed during an attempt to create a VF:
[ 1661.543624] idpf 0000:84:00.7: Device HW Reset initiated
[ 1722.923726] idpf 0000:84:00.7: Transaction timed-out (op:1 cookie:2900 vc_op:1 salt:29 timeout:60000ms)
[ 1723.353263] BUG: kernel NULL pointer dereference, address: 0000000000000028
...
[ 1723.358472] RIP: 0010:idpf_remove+0x11c/0x200 [idpf]
...
[ 1723.364973] Call Trace:
[ 1723.365475] <TASK>
[ 1723.365972] pci_device_remove+0x42/0xb0
[ 1723.366481] device_release_driver_internal+0x1a9/0x210
[ 1723.366987] pci_stop_bus_device+0x6d/0x90
[ 1723.367488] pci_stop_and_remove_bus_device+0x12/0x20
[ 1723.367971] pci_iov_remove_virtfn+0xbd/0x120
[ 1723.368309] sriov_disable+0x34/0xe0
[ 1723.368643] idpf_sriov_configure+0x58/0x140 [idpf]
[ 1723.368982] sriov_numvfs_store+0xda/0x1c0
Avoid the NULL pointer dereference by adding NULL pointer check for
vport_config[i], before freeing user_config.q_coalesce. |
| In the Linux kernel, the following vulnerability has been resolved:
crash: fix crashkernel resource shrink
When crashkernel is configured with a high reservation, shrinking its
value below the low crashkernel reservation causes two issues:
1. Invalid crashkernel resource objects
2. Kernel crash if crashkernel shrinking is done twice
For example, with crashkernel=200M,high, the kernel reserves 200MB of high
memory and some default low memory (say 256MB). The reservation appears
as:
cat /proc/iomem | grep -i crash
af000000-beffffff : Crash kernel
433000000-43f7fffff : Crash kernel
If crashkernel is then shrunk to 50MB (echo 52428800 >
/sys/kernel/kexec_crash_size), /proc/iomem still shows 256MB reserved:
af000000-beffffff : Crash kernel
Instead, it should show 50MB:
af000000-b21fffff : Crash kernel
Further shrinking crashkernel to 40MB causes a kernel crash with the
following trace (x86):
BUG: kernel NULL pointer dereference, address: 0000000000000038
PGD 0 P4D 0
Oops: 0000 [#1] PREEMPT SMP NOPTI
<snip...>
Call Trace: <TASK>
? __die_body.cold+0x19/0x27
? page_fault_oops+0x15a/0x2f0
? search_module_extables+0x19/0x60
? search_bpf_extables+0x5f/0x80
? exc_page_fault+0x7e/0x180
? asm_exc_page_fault+0x26/0x30
? __release_resource+0xd/0xb0
release_resource+0x26/0x40
__crash_shrink_memory+0xe5/0x110
crash_shrink_memory+0x12a/0x190
kexec_crash_size_store+0x41/0x80
kernfs_fop_write_iter+0x141/0x1f0
vfs_write+0x294/0x460
ksys_write+0x6d/0xf0
<snip...>
This happens because __crash_shrink_memory()/kernel/crash_core.c
incorrectly updates the crashk_res resource object even when
crashk_low_res should be updated.
Fix this by ensuring the correct crashkernel resource object is updated
when shrinking crashkernel memory. |
| In the Linux kernel, the following vulnerability has been resolved:
ring-buffer: Do not warn in ring_buffer_map_get_reader() when reader catches up
The function ring_buffer_map_get_reader() is a bit more strict than the
other get reader functions, and except for certain situations the
rb_get_reader_page() should not return NULL. If it does, it triggers a
warning.
This warning was triggering but after looking at why, it was because
another acceptable situation was happening and it wasn't checked for.
If the reader catches up to the writer and there's still data to be read
on the reader page, then the rb_get_reader_page() will return NULL as
there's no new page to get.
In this situation, the reader page should not be updated and no warning
should trigger. |
| In the Linux kernel, the following vulnerability has been resolved:
netpoll: Fix deadlock in memory allocation under spinlock
Fix a AA deadlock in refill_skbs() where memory allocation while holding
skb_pool->lock can trigger a recursive lock acquisition attempt.
The deadlock scenario occurs when the system is under severe memory
pressure:
1. refill_skbs() acquires skb_pool->lock (spinlock)
2. alloc_skb() is called while holding the lock
3. Memory allocator fails and calls slab_out_of_memory()
4. This triggers printk() for the OOM warning
5. The console output path calls netpoll_send_udp()
6. netpoll_send_udp() attempts to acquire the same skb_pool->lock
7. Deadlock: the lock is already held by the same CPU
Call stack:
refill_skbs()
spin_lock_irqsave(&skb_pool->lock) <- lock acquired
__alloc_skb()
kmem_cache_alloc_node_noprof()
slab_out_of_memory()
printk()
console_flush_all()
netpoll_send_udp()
skb_dequeue()
spin_lock_irqsave(&skb_pool->lock) <- deadlock attempt
This bug was exposed by commit 248f6571fd4c51 ("netpoll: Optimize skb
refilling on critical path") which removed refill_skbs() from the
critical path (where nested printk was being deferred), letting nested
printk being called from inside refill_skbs()
Refactor refill_skbs() to never allocate memory while holding
the spinlock.
Another possible solution to fix this problem is protecting the
refill_skbs() from nested printks, basically calling
printk_deferred_{enter,exit}() in refill_skbs(), then, any nested
pr_warn() would be deferred.
I prefer this approach, given I _think_ it might be a good idea to move
the alloc_skb() from GFP_ATOMIC to GFP_KERNEL in the future, so, having
the alloc_skb() outside of the lock will be necessary step.
There is a possible TOCTOU issue when checking for the pool length, and
queueing the new allocated skb, but, this is not an issue, given that
an extra SKB in the pool is harmless and it will be eventually used. |
| In the Linux kernel, the following vulnerability has been resolved:
bpf: Add bpf_prog_run_data_pointers()
syzbot found that cls_bpf_classify() is able to change
tc_skb_cb(skb)->drop_reason triggering a warning in sk_skb_reason_drop().
WARNING: CPU: 0 PID: 5965 at net/core/skbuff.c:1192 __sk_skb_reason_drop net/core/skbuff.c:1189 [inline]
WARNING: CPU: 0 PID: 5965 at net/core/skbuff.c:1192 sk_skb_reason_drop+0x76/0x170 net/core/skbuff.c:1214
struct tc_skb_cb has been added in commit ec624fe740b4 ("net/sched:
Extend qdisc control block with tc control block"), which added a wrong
interaction with db58ba459202 ("bpf: wire in data and data_end for
cls_act_bpf").
drop_reason was added later.
Add bpf_prog_run_data_pointers() helper to save/restore the net_sched
storage colliding with BPF data_meta/data_end. |
