| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| In the Linux kernel, the following vulnerability has been resolved:
net: rose: include node references in rose_neigh refcount
Current implementation maintains two separate reference counting
mechanisms: the 'count' field in struct rose_neigh tracks references from
rose_node structures, while the 'use' field (now refcount_t) tracks
references from rose_sock.
This patch merges these two reference counting systems using 'use' field
for proper reference management. Specifically, this patch adds incrementing
and decrementing of rose_neigh->use when rose_neigh->count is incremented
or decremented.
This patch also modifies rose_rt_free(), rose_rt_device_down() and
rose_clear_route() to properly release references to rose_neigh objects
before freeing a rose_node through rose_remove_node().
These changes ensure rose_neigh structures are properly freed only when
all references, including those from rose_node structures, are released.
As a result, this resolves a slab-use-after-free issue reported by Syzbot. |
| In the Linux kernel, the following vulnerability has been resolved:
net: rose: convert 'use' field to refcount_t
The 'use' field in struct rose_neigh is used as a reference counter but
lacks atomicity. This can lead to race conditions where a rose_neigh
structure is freed while still being referenced by other code paths.
For example, when rose_neigh->use becomes zero during an ioctl operation
via rose_rt_ioctl(), the structure may be removed while its timer is
still active, potentially causing use-after-free issues.
This patch changes the type of 'use' from unsigned short to refcount_t and
updates all code paths to use rose_neigh_hold() and rose_neigh_put() which
operate reference counts atomically. |
| In the Linux kernel, the following vulnerability has been resolved:
block: avoid possible overflow for chunk_sectors check in blk_stack_limits()
In blk_stack_limits(), we check that the t->chunk_sectors value is a
multiple of the t->physical_block_size value.
However, by finding the chunk_sectors value in bytes, we may overflow
the unsigned int which holds chunk_sectors, so change the check to be
based on sectors. |
| In the Linux kernel, the following vulnerability has been resolved:
jbd2: prevent softlockup in jbd2_log_do_checkpoint()
Both jbd2_log_do_checkpoint() and jbd2_journal_shrink_checkpoint_list()
periodically release j_list_lock after processing a batch of buffers to
avoid long hold times on the j_list_lock. However, since both functions
contend for j_list_lock, the combined time spent waiting and processing
can be significant.
jbd2_journal_shrink_checkpoint_list() explicitly calls cond_resched() when
need_resched() is true to avoid softlockups during prolonged operations.
But jbd2_log_do_checkpoint() only exits its loop when need_resched() is
true, relying on potentially sleeping functions like __flush_batch() or
wait_on_buffer() to trigger rescheduling. If those functions do not sleep,
the kernel may hit a softlockup.
watchdog: BUG: soft lockup - CPU#3 stuck for 156s! [kworker/u129:2:373]
CPU: 3 PID: 373 Comm: kworker/u129:2 Kdump: loaded Not tainted 6.6.0+ #10
Hardware name: Huawei TaiShan 2280 /BC11SPCD, BIOS 1.27 06/13/2017
Workqueue: writeback wb_workfn (flush-7:2)
pstate: 20000005 (nzCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : native_queued_spin_lock_slowpath+0x358/0x418
lr : jbd2_log_do_checkpoint+0x31c/0x438 [jbd2]
Call trace:
native_queued_spin_lock_slowpath+0x358/0x418
jbd2_log_do_checkpoint+0x31c/0x438 [jbd2]
__jbd2_log_wait_for_space+0xfc/0x2f8 [jbd2]
add_transaction_credits+0x3bc/0x418 [jbd2]
start_this_handle+0xf8/0x560 [jbd2]
jbd2__journal_start+0x118/0x228 [jbd2]
__ext4_journal_start_sb+0x110/0x188 [ext4]
ext4_do_writepages+0x3dc/0x740 [ext4]
ext4_writepages+0xa4/0x190 [ext4]
do_writepages+0x94/0x228
__writeback_single_inode+0x48/0x318
writeback_sb_inodes+0x204/0x590
__writeback_inodes_wb+0x54/0xf8
wb_writeback+0x2cc/0x3d8
wb_do_writeback+0x2e0/0x2f8
wb_workfn+0x80/0x2a8
process_one_work+0x178/0x3e8
worker_thread+0x234/0x3b8
kthread+0xf0/0x108
ret_from_fork+0x10/0x20
So explicitly call cond_resched() in jbd2_log_do_checkpoint() to avoid
softlockup. |
| In the Linux kernel, the following vulnerability has been resolved:
net: bridge: fix soft lockup in br_multicast_query_expired()
When set multicast_query_interval to a large value, the local variable
'time' in br_multicast_send_query() may overflow. If the time is smaller
than jiffies, the timer will expire immediately, and then call mod_timer()
again, which creates a loop and may trigger the following soft lockup
issue.
watchdog: BUG: soft lockup - CPU#1 stuck for 221s! [rb_consumer:66]
CPU: 1 UID: 0 PID: 66 Comm: rb_consumer Not tainted 6.16.0+ #259 PREEMPT(none)
Call Trace:
<IRQ>
__netdev_alloc_skb+0x2e/0x3a0
br_ip6_multicast_alloc_query+0x212/0x1b70
__br_multicast_send_query+0x376/0xac0
br_multicast_send_query+0x299/0x510
br_multicast_query_expired.constprop.0+0x16d/0x1b0
call_timer_fn+0x3b/0x2a0
__run_timers+0x619/0x950
run_timer_softirq+0x11c/0x220
handle_softirqs+0x18e/0x560
__irq_exit_rcu+0x158/0x1a0
sysvec_apic_timer_interrupt+0x76/0x90
</IRQ>
This issue can be reproduced with:
ip link add br0 type bridge
echo 1 > /sys/class/net/br0/bridge/multicast_querier
echo 0xffffffffffffffff >
/sys/class/net/br0/bridge/multicast_query_interval
ip link set dev br0 up
The multicast_startup_query_interval can also cause this issue. Similar to
the commit 99b40610956a ("net: bridge: mcast: add and enforce query
interval minimum"), add check for the query interval maximum to fix this
issue. |
| In the Linux kernel, the following vulnerability has been resolved:
net: gso: Forbid IPv6 TSO with extensions on devices with only IPV6_CSUM
When performing Generic Segmentation Offload (GSO) on an IPv6 packet that
contains extension headers, the kernel incorrectly requests checksum offload
if the egress device only advertises NETIF_F_IPV6_CSUM feature, which has
a strict contract: it supports checksum offload only for plain TCP or UDP
over IPv6 and explicitly does not support packets with extension headers.
The current GSO logic violates this contract by failing to disable the feature
for packets with extension headers, such as those used in GREoIPv6 tunnels.
This violation results in the device being asked to perform an operation
it cannot support, leading to a `skb_warn_bad_offload` warning and a collapse
of network throughput. While device TSO/USO is correctly bypassed in favor
of software GSO for these packets, the GSO stack must be explicitly told not
to request checksum offload.
Mask NETIF_F_IPV6_CSUM, NETIF_F_TSO6 and NETIF_F_GSO_UDP_L4
in gso_features_check if the IPv6 header contains extension headers to compute
checksum in software.
The exception is a BIG TCP extension, which, as stated in commit
68e068cabd2c6c53 ("net: reenable NETIF_F_IPV6_CSUM offload for BIG TCP packets"):
"The feature is only enabled on devices that support BIG TCP TSO.
The header is only present for PF_PACKET taps like tcpdump,
and not transmitted by physical devices."
kernel log output (truncated):
WARNING: CPU: 1 PID: 5273 at net/core/dev.c:3535 skb_warn_bad_offload+0x81/0x140
...
Call Trace:
<TASK>
skb_checksum_help+0x12a/0x1f0
validate_xmit_skb+0x1a3/0x2d0
validate_xmit_skb_list+0x4f/0x80
sch_direct_xmit+0x1a2/0x380
__dev_xmit_skb+0x242/0x670
__dev_queue_xmit+0x3fc/0x7f0
ip6_finish_output2+0x25e/0x5d0
ip6_finish_output+0x1fc/0x3f0
ip6_tnl_xmit+0x608/0xc00 [ip6_tunnel]
ip6gre_tunnel_xmit+0x1c0/0x390 [ip6_gre]
dev_hard_start_xmit+0x63/0x1c0
__dev_queue_xmit+0x6d0/0x7f0
ip6_finish_output2+0x214/0x5d0
ip6_finish_output+0x1fc/0x3f0
ip6_xmit+0x2ca/0x6f0
ip6_finish_output+0x1fc/0x3f0
ip6_xmit+0x2ca/0x6f0
inet6_csk_xmit+0xeb/0x150
__tcp_transmit_skb+0x555/0xa80
tcp_write_xmit+0x32a/0xe90
tcp_sendmsg_locked+0x437/0x1110
tcp_sendmsg+0x2f/0x50
...
skb linear: 00000000: e4 3d 1a 7d ec 30 e4 3d 1a 7e 5d 90 86 dd 60 0e
skb linear: 00000010: 00 0a 1b 34 3c 40 20 11 00 00 00 00 00 00 00 00
skb linear: 00000020: 00 00 00 00 00 12 20 11 00 00 00 00 00 00 00 00
skb linear: 00000030: 00 00 00 00 00 11 2f 00 04 01 04 01 01 00 00 00
skb linear: 00000040: 86 dd 60 0e 00 0a 1b 00 06 40 20 23 00 00 00 00
skb linear: 00000050: 00 00 00 00 00 00 00 00 00 12 20 23 00 00 00 00
skb linear: 00000060: 00 00 00 00 00 00 00 00 00 11 bf 96 14 51 13 f9
skb linear: 00000070: ae 27 a0 a8 2b e3 80 18 00 40 5b 6f 00 00 01 01
skb linear: 00000080: 08 0a 42 d4 50 d5 4b 70 f8 1a |
| In the Linux kernel, the following vulnerability has been resolved:
netfilter: ctnetlink: remove refcounting in expectation dumpers
Same pattern as previous patch: do not keep the expectation object
alive via refcount, only store a cookie value and then use that
as the skip hint for dump resumption.
AFAICS this has the same issue as the one resolved in the conntrack
dumper, when we do
if (!refcount_inc_not_zero(&exp->use))
to increment the refcount, there is a chance that exp == last, which
causes a double-increment of the refcount and subsequent memory leak. |
| In the Linux kernel, the following vulnerability has been resolved:
fs: Prevent file descriptor table allocations exceeding INT_MAX
When sysctl_nr_open is set to a very high value (for example, 1073741816
as set by systemd), processes attempting to use file descriptors near
the limit can trigger massive memory allocation attempts that exceed
INT_MAX, resulting in a WARNING in mm/slub.c:
WARNING: CPU: 0 PID: 44 at mm/slub.c:5027 __kvmalloc_node_noprof+0x21a/0x288
This happens because kvmalloc_array() and kvmalloc() check if the
requested size exceeds INT_MAX and emit a warning when the allocation is
not flagged with __GFP_NOWARN.
Specifically, when nr_open is set to 1073741816 (0x3ffffff8) and a
process calls dup2(oldfd, 1073741880), the kernel attempts to allocate:
- File descriptor array: 1073741880 * 8 bytes = 8,589,935,040 bytes
- Multiple bitmaps: ~400MB
- Total allocation size: > 8GB (exceeding INT_MAX = 2,147,483,647)
Reproducer:
1. Set /proc/sys/fs/nr_open to 1073741816:
# echo 1073741816 > /proc/sys/fs/nr_open
2. Run a program that uses a high file descriptor:
#include <unistd.h>
#include <sys/resource.h>
int main() {
struct rlimit rlim = {1073741824, 1073741824};
setrlimit(RLIMIT_NOFILE, &rlim);
dup2(2, 1073741880); // Triggers the warning
return 0;
}
3. Observe WARNING in dmesg at mm/slub.c:5027
systemd commit a8b627a introduced automatic bumping of fs.nr_open to the
maximum possible value. The rationale was that systems with memory
control groups (memcg) no longer need separate file descriptor limits
since memory is properly accounted. However, this change overlooked
that:
1. The kernel's allocation functions still enforce INT_MAX as a maximum
size regardless of memcg accounting
2. Programs and tests that legitimately test file descriptor limits can
inadvertently trigger massive allocations
3. The resulting allocations (>8GB) are impractical and will always fail
systemd's algorithm starts with INT_MAX and keeps halving the value
until the kernel accepts it. On most systems, this results in nr_open
being set to 1073741816 (0x3ffffff8), which is just under 1GB of file
descriptors.
While processes rarely use file descriptors near this limit in normal
operation, certain selftests (like
tools/testing/selftests/core/unshare_test.c) and programs that test file
descriptor limits can trigger this issue.
Fix this by adding a check in alloc_fdtable() to ensure the requested
allocation size does not exceed INT_MAX. This causes the operation to
fail with -EMFILE instead of triggering a kernel warning and avoids the
impractical >8GB memory allocation request. |
| In the Linux kernel, the following vulnerability has been resolved:
bpf: Forget ranges when refining tnum after JSET
Syzbot reported a kernel warning due to a range invariant violation on
the following BPF program.
0: call bpf_get_netns_cookie
1: if r0 == 0 goto <exit>
2: if r0 & Oxffffffff goto <exit>
The issue is on the path where we fall through both jumps.
That path is unreachable at runtime: after insn 1, we know r0 != 0, but
with the sign extension on the jset, we would only fallthrough insn 2
if r0 == 0. Unfortunately, is_branch_taken() isn't currently able to
figure this out, so the verifier walks all branches. The verifier then
refines the register bounds using the second condition and we end
up with inconsistent bounds on this unreachable path:
1: if r0 == 0 goto <exit>
r0: u64=[0x1, 0xffffffffffffffff] var_off=(0, 0xffffffffffffffff)
2: if r0 & 0xffffffff goto <exit>
r0 before reg_bounds_sync: u64=[0x1, 0xffffffffffffffff] var_off=(0, 0)
r0 after reg_bounds_sync: u64=[0x1, 0] var_off=(0, 0)
Improving the range refinement for JSET to cover all cases is tricky. We
also don't expect many users to rely on JSET given LLVM doesn't generate
those instructions. So instead of improving the range refinement for
JSETs, Eduard suggested we forget the ranges whenever we're narrowing
tnums after a JSET. This patch implements that approach. |
| In the Linux kernel, the following vulnerability has been resolved:
crypto: qat - flush misc workqueue during device shutdown
Repeated loading and unloading of a device specific QAT driver, for
example qat_4xxx, in a tight loop can lead to a crash due to a
use-after-free scenario. This occurs when a power management (PM)
interrupt triggers just before the device-specific driver (e.g.,
qat_4xxx.ko) is unloaded, while the core driver (intel_qat.ko) remains
loaded.
Since the driver uses a shared workqueue (`qat_misc_wq`) across all
devices and owned by intel_qat.ko, a deferred routine from the
device-specific driver may still be pending in the queue. If this
routine executes after the driver is unloaded, it can dereference freed
memory, resulting in a page fault and kernel crash like the following:
BUG: unable to handle page fault for address: ffa000002e50a01c
#PF: supervisor read access in kernel mode
RIP: 0010:pm_bh_handler+0x1d2/0x250 [intel_qat]
Call Trace:
pm_bh_handler+0x1d2/0x250 [intel_qat]
process_one_work+0x171/0x340
worker_thread+0x277/0x3a0
kthread+0xf0/0x120
ret_from_fork+0x2d/0x50
To prevent this, flush the misc workqueue during device shutdown to
ensure that all pending work items are completed before the driver is
unloaded.
Note: This approach may slightly increase shutdown latency if the
workqueue contains jobs from other devices, but it ensures correctness
and stability. |
| In the Linux kernel, the following vulnerability has been resolved:
fs/buffer: fix use-after-free when call bh_read() helper
There's issue as follows:
BUG: KASAN: stack-out-of-bounds in end_buffer_read_sync+0xe3/0x110
Read of size 8 at addr ffffc9000168f7f8 by task swapper/3/0
CPU: 3 UID: 0 PID: 0 Comm: swapper/3 Not tainted 6.16.0-862.14.0.6.x86_64
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996)
Call Trace:
<IRQ>
dump_stack_lvl+0x55/0x70
print_address_description.constprop.0+0x2c/0x390
print_report+0xb4/0x270
kasan_report+0xb8/0xf0
end_buffer_read_sync+0xe3/0x110
end_bio_bh_io_sync+0x56/0x80
blk_update_request+0x30a/0x720
scsi_end_request+0x51/0x2b0
scsi_io_completion+0xe3/0x480
? scsi_device_unbusy+0x11e/0x160
blk_complete_reqs+0x7b/0x90
handle_softirqs+0xef/0x370
irq_exit_rcu+0xa5/0xd0
sysvec_apic_timer_interrupt+0x6e/0x90
</IRQ>
Above issue happens when do ntfs3 filesystem mount, issue may happens
as follows:
mount IRQ
ntfs_fill_super
read_cache_page
do_read_cache_folio
filemap_read_folio
mpage_read_folio
do_mpage_readpage
ntfs_get_block_vbo
bh_read
submit_bh
wait_on_buffer(bh);
blk_complete_reqs
scsi_io_completion
scsi_end_request
blk_update_request
end_bio_bh_io_sync
end_buffer_read_sync
__end_buffer_read_notouch
unlock_buffer
wait_on_buffer(bh);--> return will return to caller
put_bh
--> trigger stack-out-of-bounds
In the mpage_read_folio() function, the stack variable 'map_bh' is
passed to ntfs_get_block_vbo(). Once unlock_buffer() unlocks and
wait_on_buffer() returns to continue processing, the stack variable
is likely to be reclaimed. Consequently, during the end_buffer_read_sync()
process, calling put_bh() may result in stack overrun.
If the bh is not allocated on the stack, it belongs to a folio. Freeing
a buffer head which belongs to a folio is done by drop_buffers() which
will fail to free buffers which are still locked. So it is safe to call
put_bh() before __end_buffer_read_notouch(). |
| In the Linux kernel, the following vulnerability has been resolved:
x86/cpu/hygon: Add missing resctrl_cpu_detect() in bsp_init helper
Since
923f3a2b48bd ("x86/resctrl: Query LLC monitoring properties once during boot")
resctrl_cpu_detect() has been moved from common CPU initialization code to
the vendor-specific BSP init helper, while Hygon didn't put that call in their
code.
This triggers a division by zero fault during early booting stage on our
machines with X86_FEATURE_CQM* supported, where get_rdt_mon_resources() tries
to calculate mon_l3_config with uninitialized boot_cpu_data.x86_cache_occ_scale.
Add the missing resctrl_cpu_detect() in the Hygon BSP init helper.
[ bp: Massage commit message. ] |
| In the Linux kernel, the following vulnerability has been resolved:
net: usb: asix_devices: Fix PHY address mask in MDIO bus initialization
Syzbot reported shift-out-of-bounds exception on MDIO bus initialization.
The PHY address should be masked to 5 bits (0-31). Without this
mask, invalid PHY addresses could be used, potentially causing issues
with MDIO bus operations.
Fix this by masking the PHY address with 0x1f (31 decimal) to ensure
it stays within the valid range. |
| In the Linux kernel, the following vulnerability has been resolved:
netfilter: nf_reject: don't leak dst refcount for loopback packets
recent patches to add a WARN() when replacing skb dst entry found an
old bug:
WARNING: include/linux/skbuff.h:1165 skb_dst_check_unset include/linux/skbuff.h:1164 [inline]
WARNING: include/linux/skbuff.h:1165 skb_dst_set include/linux/skbuff.h:1210 [inline]
WARNING: include/linux/skbuff.h:1165 nf_reject_fill_skb_dst+0x2a4/0x330 net/ipv4/netfilter/nf_reject_ipv4.c:234
[..]
Call Trace:
nf_send_unreach+0x17b/0x6e0 net/ipv4/netfilter/nf_reject_ipv4.c:325
nft_reject_inet_eval+0x4bc/0x690 net/netfilter/nft_reject_inet.c:27
expr_call_ops_eval net/netfilter/nf_tables_core.c:237 [inline]
..
This is because blamed commit forgot about loopback packets.
Such packets already have a dst_entry attached, even at PRE_ROUTING stage.
Instead of checking hook just check if the skb already has a route
attached to it. |
| In the Linux kernel, the following vulnerability has been resolved:
netlink: avoid infinite retry looping in netlink_unicast()
netlink_attachskb() checks for the socket's read memory allocation
constraints. Firstly, it has:
rmem < READ_ONCE(sk->sk_rcvbuf)
to check if the just increased rmem value fits into the socket's receive
buffer. If not, it proceeds and tries to wait for the memory under:
rmem + skb->truesize > READ_ONCE(sk->sk_rcvbuf)
The checks don't cover the case when skb->truesize + sk->sk_rmem_alloc is
equal to sk->sk_rcvbuf. Thus the function neither successfully accepts
these conditions, nor manages to reschedule the task - and is called in
retry loop for indefinite time which is caught as:
rcu: INFO: rcu_sched self-detected stall on CPU
rcu: 0-....: (25999 ticks this GP) idle=ef2/1/0x4000000000000000 softirq=262269/262269 fqs=6212
(t=26000 jiffies g=230833 q=259957)
NMI backtrace for cpu 0
CPU: 0 PID: 22 Comm: kauditd Not tainted 5.10.240 #68
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.17.0-4.fc42 04/01/2014
Call Trace:
<IRQ>
dump_stack lib/dump_stack.c:120
nmi_cpu_backtrace.cold lib/nmi_backtrace.c:105
nmi_trigger_cpumask_backtrace lib/nmi_backtrace.c:62
rcu_dump_cpu_stacks kernel/rcu/tree_stall.h:335
rcu_sched_clock_irq.cold kernel/rcu/tree.c:2590
update_process_times kernel/time/timer.c:1953
tick_sched_handle kernel/time/tick-sched.c:227
tick_sched_timer kernel/time/tick-sched.c:1399
__hrtimer_run_queues kernel/time/hrtimer.c:1652
hrtimer_interrupt kernel/time/hrtimer.c:1717
__sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1113
asm_call_irq_on_stack arch/x86/entry/entry_64.S:808
</IRQ>
netlink_attachskb net/netlink/af_netlink.c:1234
netlink_unicast net/netlink/af_netlink.c:1349
kauditd_send_queue kernel/audit.c:776
kauditd_thread kernel/audit.c:897
kthread kernel/kthread.c:328
ret_from_fork arch/x86/entry/entry_64.S:304
Restore the original behavior of the check which commit in Fixes
accidentally missed when restructuring the code.
Found by Linux Verification Center (linuxtesting.org). |
| In the Linux kernel, the following vulnerability has been resolved:
net: usb: asix_devices: add phy_mask for ax88772 mdio bus
Without setting phy_mask for ax88772 mdio bus, current driver may create
at most 32 mdio phy devices with phy address range from 0x00 ~ 0x1f.
DLink DUB-E100 H/W Ver B1 is such a device. However, only one main phy
device will bind to net phy driver. This is creating issue during system
suspend/resume since phy_polling_mode() in phy_state_machine() will
directly deference member of phydev->drv for non-main phy devices. Then
NULL pointer dereference issue will occur. Due to only external phy or
internal phy is necessary, add phy_mask for ax88772 mdio bus to workarnoud
the issue. |
| In the Linux kernel, the following vulnerability has been resolved:
netfilter: ctnetlink: fix refcount leak on table dump
There is a reference count leak in ctnetlink_dump_table():
if (res < 0) {
nf_conntrack_get(&ct->ct_general); // HERE
cb->args[1] = (unsigned long)ct;
...
While its very unlikely, its possible that ct == last.
If this happens, then the refcount of ct was already incremented.
This 2nd increment is never undone.
This prevents the conntrack object from being released, which in turn
keeps prevents cnet->count from dropping back to 0.
This will then block the netns dismantle (or conntrack rmmod) as
nf_conntrack_cleanup_net_list() will wait forever.
This can be reproduced by running conntrack_resize.sh selftest in a loop.
It takes ~20 minutes for me on a preemptible kernel on average before
I see a runaway kworker spinning in nf_conntrack_cleanup_net_list.
One fix would to change this to:
if (res < 0) {
if (ct != last)
nf_conntrack_get(&ct->ct_general);
But this reference counting isn't needed in the first place.
We can just store a cookie value instead.
A followup patch will do the same for ctnetlink_exp_dump_table,
it looks to me as if this has the same problem and like
ctnetlink_dump_table, we only need a 'skip hint', not the actual
object so we can apply the same cookie strategy there as well. |
| In the Linux kernel, the following vulnerability has been resolved:
rcu/nocb: Fix possible invalid rdp's->nocb_cb_kthread pointer access
In the preparation stage of CPU online, if the corresponding
the rdp's->nocb_cb_kthread does not exist, will be created,
there is a situation where the rdp's rcuop kthreads creation fails,
and then de-offload this CPU's rdp, does not assign this CPU's
rdp->nocb_cb_kthread pointer, but this rdp's->nocb_gp_rdp and
rdp's->rdp_gp->nocb_gp_kthread is still valid.
This will cause the subsequent re-offload operation of this offline
CPU, which will pass the conditional check and the kthread_unpark()
will access invalid rdp's->nocb_cb_kthread pointer.
This commit therefore use rdp's->nocb_gp_kthread instead of
rdp_gp's->nocb_gp_kthread for safety check. |
| In the Linux kernel, the following vulnerability has been resolved:
mm/ptdump: take the memory hotplug lock inside ptdump_walk_pgd()
Memory hot remove unmaps and tears down various kernel page table regions
as required. The ptdump code can race with concurrent modifications of
the kernel page tables. When leaf entries are modified concurrently, the
dump code may log stale or inconsistent information for a VA range, but
this is otherwise not harmful.
But when intermediate levels of kernel page table are freed, the dump code
will continue to use memory that has been freed and potentially
reallocated for another purpose. In such cases, the ptdump code may
dereference bogus addresses, leading to a number of potential problems.
To avoid the above mentioned race condition, platforms such as arm64,
riscv and s390 take memory hotplug lock, while dumping kernel page table
via the sysfs interface /sys/kernel/debug/kernel_page_tables.
Similar race condition exists while checking for pages that might have
been marked W+X via /sys/kernel/debug/kernel_page_tables/check_wx_pages
which in turn calls ptdump_check_wx(). Instead of solving this race
condition again, let's just move the memory hotplug lock inside generic
ptdump_check_wx() which will benefit both the scenarios.
Drop get_online_mems() and put_online_mems() combination from all existing
platform ptdump code paths. |
| In the Linux kernel, the following vulnerability has been resolved:
eventpoll: Fix semi-unbounded recursion
Ensure that epoll instances can never form a graph deeper than
EP_MAX_NESTS+1 links.
Currently, ep_loop_check_proc() ensures that the graph is loop-free and
does some recursion depth checks, but those recursion depth checks don't
limit the depth of the resulting tree for two reasons:
- They don't look upwards in the tree.
- If there are multiple downwards paths of different lengths, only one of
the paths is actually considered for the depth check since commit
28d82dc1c4ed ("epoll: limit paths").
Essentially, the current recursion depth check in ep_loop_check_proc() just
serves to prevent it from recursing too deeply while checking for loops.
A more thorough check is done in reverse_path_check() after the new graph
edge has already been created; this checks, among other things, that no
paths going upwards from any non-epoll file with a length of more than 5
edges exist. However, this check does not apply to non-epoll files.
As a result, it is possible to recurse to a depth of at least roughly 500,
tested on v6.15. (I am unsure if deeper recursion is possible; and this may
have changed with commit 8c44dac8add7 ("eventpoll: Fix priority inversion
problem").)
To fix it:
1. In ep_loop_check_proc(), note the subtree depth of each visited node,
and use subtree depths for the total depth calculation even when a subtree
has already been visited.
2. Add ep_get_upwards_depth_proc() for similarly determining the maximum
depth of an upwards walk.
3. In ep_loop_check(), use these values to limit the total path length
between epoll nodes to EP_MAX_NESTS edges. |
