Security Vulnerabilities - CVEs Published In July 2024
In the Linux kernel, the following vulnerability has been resolved:
powerpc/eeh: avoid possible crash when edev->pdev changes
If a PCI device is removed during eeh_pe_report_edev(), edev->pdev
will change and can cause a crash, hold the PCI rescan/remove lock
while taking a copy of edev->pdev->bus.
CVSS Score
5.5
EPSS Score
0.001
Published
2024-07-29
In the Linux kernel, the following vulnerability has been resolved:
ibmvnic: Add tx check to prevent skb leak
Below is a summary of how the driver stores a reference to an skb during
transmit:
tx_buff[free_map[consumer_index]]->skb = new_skb;
free_map[consumer_index] = IBMVNIC_INVALID_MAP;
consumer_index ++;
Where variable data looks like this:
free_map == [4, IBMVNIC_INVALID_MAP, IBMVNIC_INVALID_MAP, 0, 3]
consumer_index^
tx_buff == [skb=null, skb=<ptr>, skb=<ptr>, skb=null, skb=null]
The driver has checks to ensure that free_map[consumer_index] pointed to
a valid index but there was no check to ensure that this index pointed
to an unused/null skb address. So, if, by some chance, our free_map and
tx_buff lists become out of sync then we were previously risking an
skb memory leak. This could then cause tcp congestion control to stop
sending packets, eventually leading to ETIMEDOUT.
Therefore, add a conditional to ensure that the skb address is null. If
not then warn the user (because this is still a bug that should be
patched) and free the old pointer to prevent memleak/tcp problems.
CVSS Score
5.5
EPSS Score
0.0
Published
2024-07-29
In the Linux kernel, the following vulnerability has been resolved:
KVM: PPC: Book3S HV: Prevent UAF in kvm_spapr_tce_attach_iommu_group()
Al reported a possible use-after-free (UAF) in kvm_spapr_tce_attach_iommu_group().
It looks up `stt` from tablefd, but then continues to use it after doing
fdput() on the returned fd. After the fdput() the tablefd is free to be
closed by another thread. The close calls kvm_spapr_tce_release() and
then release_spapr_tce_table() (via call_rcu()) which frees `stt`.
Although there are calls to rcu_read_lock() in
kvm_spapr_tce_attach_iommu_group() they are not sufficient to prevent
the UAF, because `stt` is used outside the locked regions.
With an artifcial delay after the fdput() and a userspace program which
triggers the race, KASAN detects the UAF:
BUG: KASAN: slab-use-after-free in kvm_spapr_tce_attach_iommu_group+0x298/0x720 [kvm]
Read of size 4 at addr c000200027552c30 by task kvm-vfio/2505
CPU: 54 PID: 2505 Comm: kvm-vfio Not tainted 6.10.0-rc3-next-20240612-dirty #1
Hardware name: 8335-GTH POWER9 0x4e1202 opal:skiboot-v6.5.3-35-g1851b2a06 PowerNV
Call Trace:
dump_stack_lvl+0xb4/0x108 (unreliable)
print_report+0x2b4/0x6ec
kasan_report+0x118/0x2b0
__asan_load4+0xb8/0xd0
kvm_spapr_tce_attach_iommu_group+0x298/0x720 [kvm]
kvm_vfio_set_attr+0x524/0xac0 [kvm]
kvm_device_ioctl+0x144/0x240 [kvm]
sys_ioctl+0x62c/0x1810
system_call_exception+0x190/0x440
system_call_vectored_common+0x15c/0x2ec
...
Freed by task 0:
...
kfree+0xec/0x3e0
release_spapr_tce_table+0xd4/0x11c [kvm]
rcu_core+0x568/0x16a0
handle_softirqs+0x23c/0x920
do_softirq_own_stack+0x6c/0x90
do_softirq_own_stack+0x58/0x90
__irq_exit_rcu+0x218/0x2d0
irq_exit+0x30/0x80
arch_local_irq_restore+0x128/0x230
arch_local_irq_enable+0x1c/0x30
cpuidle_enter_state+0x134/0x5cc
cpuidle_enter+0x6c/0xb0
call_cpuidle+0x7c/0x100
do_idle+0x394/0x410
cpu_startup_entry+0x60/0x70
start_secondary+0x3fc/0x410
start_secondary_prolog+0x10/0x14
Fix it by delaying the fdput() until `stt` is no longer in use, which
is effectively the entire function. To keep the patch minimal add a call
to fdput() at each of the existing return paths. Future work can convert
the function to goto or __cleanup style cleanup.
With the fix in place the test case no longer triggers the UAF.
CVSS Score
7.8
EPSS Score
0.0
Published
2024-07-29
In the Linux kernel, the following vulnerability has been resolved:
skmsg: Skip zero length skb in sk_msg_recvmsg
When running BPF selftests (./test_progs -t sockmap_basic) on a Loongarch
platform, the following kernel panic occurs:
[...]
Oops[#1]:
CPU: 22 PID: 2824 Comm: test_progs Tainted: G OE 6.10.0-rc2+ #18
Hardware name: LOONGSON Dabieshan/Loongson-TC542F0, BIOS Loongson-UDK2018
... ...
ra: 90000000048bf6c0 sk_msg_recvmsg+0x120/0x560
ERA: 9000000004162774 copy_page_to_iter+0x74/0x1c0
CRMD: 000000b0 (PLV0 -IE -DA +PG DACF=CC DACM=CC -WE)
PRMD: 0000000c (PPLV0 +PIE +PWE)
EUEN: 00000007 (+FPE +SXE +ASXE -BTE)
ECFG: 00071c1d (LIE=0,2-4,10-12 VS=7)
ESTAT: 00010000 [PIL] (IS= ECode=1 EsubCode=0)
BADV: 0000000000000040
PRID: 0014c011 (Loongson-64bit, Loongson-3C5000)
Modules linked in: bpf_testmod(OE) xt_CHECKSUM xt_MASQUERADE xt_conntrack
Process test_progs (pid: 2824, threadinfo=0000000000863a31, task=...)
Stack : ...
Call Trace:
[<9000000004162774>] copy_page_to_iter+0x74/0x1c0
[<90000000048bf6c0>] sk_msg_recvmsg+0x120/0x560
[<90000000049f2b90>] tcp_bpf_recvmsg_parser+0x170/0x4e0
[<90000000049aae34>] inet_recvmsg+0x54/0x100
[<900000000481ad5c>] sock_recvmsg+0x7c/0xe0
[<900000000481e1a8>] __sys_recvfrom+0x108/0x1c0
[<900000000481e27c>] sys_recvfrom+0x1c/0x40
[<9000000004c076ec>] do_syscall+0x8c/0xc0
[<9000000003731da4>] handle_syscall+0xc4/0x160
Code: ...
---[ end trace 0000000000000000 ]---
Kernel panic - not syncing: Fatal exception
Kernel relocated by 0x3510000
.text @ 0x9000000003710000
.data @ 0x9000000004d70000
.bss @ 0x9000000006469400
---[ end Kernel panic - not syncing: Fatal exception ]---
[...]
This crash happens every time when running sockmap_skb_verdict_shutdown
subtest in sockmap_basic.
This crash is because a NULL pointer is passed to page_address() in the
sk_msg_recvmsg(). Due to the different implementations depending on the
architecture, page_address(NULL) will trigger a panic on Loongarch
platform but not on x86 platform. So this bug was hidden on x86 platform
for a while, but now it is exposed on Loongarch platform. The root cause
is that a zero length skb (skb->len == 0) was put on the queue.
This zero length skb is a TCP FIN packet, which was sent by shutdown(),
invoked in test_sockmap_skb_verdict_shutdown():
shutdown(p1, SHUT_WR);
In this case, in sk_psock_skb_ingress_enqueue(), num_sge is zero, and no
page is put to this sge (see sg_set_page in sg_set_page), but this empty
sge is queued into ingress_msg list.
And in sk_msg_recvmsg(), this empty sge is used, and a NULL page is got by
sg_page(sge). Pass this NULL page to copy_page_to_iter(), which passes it
to kmap_local_page() and to page_address(), then kernel panics.
To solve this, we should skip this zero length skb. So in sk_msg_recvmsg(),
if copy is zero, that means it's a zero length skb, skip invoking
copy_page_to_iter(). We are using the EFAULT return triggered by
copy_page_to_iter to check for is_fin in tcp_bpf.c.
CVSS Score
5.5
EPSS Score
0.0
Published
2024-07-29
In the Linux kernel, the following vulnerability has been resolved:
filelock: fix potential use-after-free in posix_lock_inode
Light Hsieh reported a KASAN UAF warning in trace_posix_lock_inode().
The request pointer had been changed earlier to point to a lock entry
that was added to the inode's list. However, before the tracepoint could
fire, another task raced in and freed that lock.
Fix this by moving the tracepoint inside the spinlock, which should
ensure that this doesn't happen.
CVSS Score
7.0
EPSS Score
0.0
Published
2024-07-29
In the Linux kernel, the following vulnerability has been resolved:
vfio/pci: Init the count variable in collecting hot-reset devices
The count variable is used without initialization, it results in mistakes
in the device counting and crashes the userspace if the get hot reset info
path is triggered.
CVSS Score
5.5
EPSS Score
0.0
Published
2024-07-29
In the Linux kernel, the following vulnerability has been resolved:
scsi: ufs: core: Fix ufshcd_abort_one racing issue
When ufshcd_abort_one is racing with the completion ISR, the completed tag
of the request's mq_hctx pointer will be set to NULL by ISR. Return
success when request is completed by ISR because ufshcd_abort_one does not
need to do anything.
The racing flow is:
Thread A
ufshcd_err_handler step 1
...
ufshcd_abort_one
ufshcd_try_to_abort_task
ufshcd_cmd_inflight(true) step 3
ufshcd_mcq_req_to_hwq
blk_mq_unique_tag
rq->mq_hctx->queue_num step 5
Thread B
ufs_mtk_mcq_intr(cq complete ISR) step 2
scsi_done
...
__blk_mq_free_request
rq->mq_hctx = NULL; step 4
Below is KE back trace.
ufshcd_try_to_abort_task: cmd at tag 41 not pending in the device.
ufshcd_try_to_abort_task: cmd at tag=41 is cleared.
Aborting tag 41 / CDB 0x28 succeeded
Unable to handle kernel NULL pointer dereference at virtual address 0000000000000194
pc : [0xffffffddd7a79bf8] blk_mq_unique_tag+0x8/0x14
lr : [0xffffffddd6155b84] ufshcd_mcq_req_to_hwq+0x1c/0x40 [ufs_mediatek_mod_ise]
do_mem_abort+0x58/0x118
el1_abort+0x3c/0x5c
el1h_64_sync_handler+0x54/0x90
el1h_64_sync+0x68/0x6c
blk_mq_unique_tag+0x8/0x14
ufshcd_err_handler+0xae4/0xfa8 [ufs_mediatek_mod_ise]
process_one_work+0x208/0x4fc
worker_thread+0x228/0x438
kthread+0x104/0x1d4
ret_from_fork+0x10/0x20
CVSS Score
5.5
EPSS Score
0.0
Published
2024-07-29
In the Linux kernel, the following vulnerability has been resolved:
scsi: ufs: core: Fix ufshcd_clear_cmd racing issue
When ufshcd_clear_cmd is racing with the completion ISR, the completed tag
of the request's mq_hctx pointer will be set to NULL by the ISR. And
ufshcd_clear_cmd's call to ufshcd_mcq_req_to_hwq will get NULL pointer KE.
Return success when the request is completed by ISR because sq does not
need cleanup.
The racing flow is:
Thread A
ufshcd_err_handler step 1
ufshcd_try_to_abort_task
ufshcd_cmd_inflight(true) step 3
ufshcd_clear_cmd
...
ufshcd_mcq_req_to_hwq
blk_mq_unique_tag
rq->mq_hctx->queue_num step 5
Thread B
ufs_mtk_mcq_intr(cq complete ISR) step 2
scsi_done
...
__blk_mq_free_request
rq->mq_hctx = NULL; step 4
Below is KE back trace:
ufshcd_try_to_abort_task: cmd pending in the device. tag = 6
Unable to handle kernel NULL pointer dereference at virtual address 0000000000000194
pc : [0xffffffd589679bf8] blk_mq_unique_tag+0x8/0x14
lr : [0xffffffd5862f95b4] ufshcd_mcq_sq_cleanup+0x6c/0x1cc [ufs_mediatek_mod_ise]
Workqueue: ufs_eh_wq_0 ufshcd_err_handler [ufs_mediatek_mod_ise]
Call trace:
dump_backtrace+0xf8/0x148
show_stack+0x18/0x24
dump_stack_lvl+0x60/0x7c
dump_stack+0x18/0x3c
mrdump_common_die+0x24c/0x398 [mrdump]
ipanic_die+0x20/0x34 [mrdump]
notify_die+0x80/0xd8
die+0x94/0x2b8
__do_kernel_fault+0x264/0x298
do_page_fault+0xa4/0x4b8
do_translation_fault+0x38/0x54
do_mem_abort+0x58/0x118
el1_abort+0x3c/0x5c
el1h_64_sync_handler+0x54/0x90
el1h_64_sync+0x68/0x6c
blk_mq_unique_tag+0x8/0x14
ufshcd_clear_cmd+0x34/0x118 [ufs_mediatek_mod_ise]
ufshcd_try_to_abort_task+0x2c8/0x5b4 [ufs_mediatek_mod_ise]
ufshcd_err_handler+0xa7c/0xfa8 [ufs_mediatek_mod_ise]
process_one_work+0x208/0x4fc
worker_thread+0x228/0x438
kthread+0x104/0x1d4
ret_from_fork+0x10/0x20
CVSS Score
5.5
EPSS Score
0.0
Published
2024-07-29
In the Linux kernel, the following vulnerability has been resolved:
mm: prevent derefencing NULL ptr in pfn_section_valid()
Commit 5ec8e8ea8b77 ("mm/sparsemem: fix race in accessing
memory_section->usage") changed pfn_section_valid() to add a READ_ONCE()
call around "ms->usage" to fix a race with section_deactivate() where
ms->usage can be cleared. The READ_ONCE() call, by itself, is not enough
to prevent NULL pointer dereference. We need to check its value before
dereferencing it.
CVSS Score
5.5
EPSS Score
0.001
Published
2024-07-29
In the Linux kernel, the following vulnerability has been resolved:
cachefiles: fix slab-use-after-free in cachefiles_withdraw_cookie()
We got the following issue in our fault injection stress test:
==================================================================
BUG: KASAN: slab-use-after-free in cachefiles_withdraw_cookie+0x4d9/0x600
Read of size 8 at addr ffff888118efc000 by task kworker/u78:0/109
CPU: 13 PID: 109 Comm: kworker/u78:0 Not tainted 6.8.0-dirty #566
Call Trace:
<TASK>
kasan_report+0x93/0xc0
cachefiles_withdraw_cookie+0x4d9/0x600
fscache_cookie_state_machine+0x5c8/0x1230
fscache_cookie_worker+0x91/0x1c0
process_one_work+0x7fa/0x1800
[...]
Allocated by task 117:
kmalloc_trace+0x1b3/0x3c0
cachefiles_acquire_volume+0xf3/0x9c0
fscache_create_volume_work+0x97/0x150
process_one_work+0x7fa/0x1800
[...]
Freed by task 120301:
kfree+0xf1/0x2c0
cachefiles_withdraw_cache+0x3fa/0x920
cachefiles_put_unbind_pincount+0x1f6/0x250
cachefiles_daemon_release+0x13b/0x290
__fput+0x204/0xa00
task_work_run+0x139/0x230
do_exit+0x87a/0x29b0
[...]
==================================================================
Following is the process that triggers the issue:
p1 | p2
------------------------------------------------------------
fscache_begin_lookup
fscache_begin_volume_access
fscache_cache_is_live(fscache_cache)
cachefiles_daemon_release
cachefiles_put_unbind_pincount
cachefiles_daemon_unbind
cachefiles_withdraw_cache
fscache_withdraw_cache
fscache_set_cache_state(cache, FSCACHE_CACHE_IS_WITHDRAWN);
cachefiles_withdraw_objects(cache)
fscache_wait_for_objects(fscache)
atomic_read(&fscache_cache->object_count) == 0
fscache_perform_lookup
cachefiles_lookup_cookie
cachefiles_alloc_object
refcount_set(&object->ref, 1);
object->volume = volume
fscache_count_object(vcookie->cache);
atomic_inc(&fscache_cache->object_count)
cachefiles_withdraw_volumes
cachefiles_withdraw_volume
fscache_withdraw_volume
__cachefiles_free_volume
kfree(cachefiles_volume)
fscache_cookie_state_machine
cachefiles_withdraw_cookie
cache = object->volume->cache;
// cachefiles_volume UAF !!!
After setting FSCACHE_CACHE_IS_WITHDRAWN, wait for all the cookie lookups
to complete first, and then wait for fscache_cache->object_count == 0 to
avoid the cookie exiting after the volume has been freed and triggering
the above issue. Therefore call fscache_withdraw_volume() before calling
cachefiles_withdraw_objects().
This way, after setting FSCACHE_CACHE_IS_WITHDRAWN, only the following two
cases will occur:
1) fscache_begin_lookup fails in fscache_begin_volume_access().
2) fscache_withdraw_volume() will ensure that fscache_count_object() has
been executed before calling fscache_wait_for_objects().
CVSS Score
7.0
EPSS Score
0.001
Published
2024-07-29