| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| In the Linux kernel, the following vulnerability has been resolved:
dmaengine: mmp_pdma: Fix race condition in mmp_pdma_residue()
Add proper locking in mmp_pdma_residue() to prevent use-after-free when
accessing descriptor list and descriptor contents.
The race occurs when multiple threads call tx_status() while the tasklet
on another CPU is freeing completed descriptors:
CPU 0 CPU 1
----- -----
mmp_pdma_tx_status()
mmp_pdma_residue()
-> NO LOCK held
list_for_each_entry(sw, ..)
DMA interrupt
dma_do_tasklet()
-> spin_lock(&desc_lock)
list_move(sw->node, ...)
spin_unlock(&desc_lock)
| dma_pool_free(sw) <- FREED!
-> access sw->desc <- UAF!
This issue can be reproduced when running dmatest on the same channel with
multiple threads (threads_per_chan > 1).
Fix by protecting the chain_running list iteration and descriptor access
with the chan->desc_lock spinlock. |
| In the Linux kernel, the following vulnerability has been resolved:
riscv: Sanitize syscall table indexing under speculation
The syscall number is a user-controlled value used to index into the
syscall table. Use array_index_nospec() to clamp this value after the
bounds check to prevent speculative out-of-bounds access and subsequent
data leakage via cache side channels. |
| In the Linux kernel, the following vulnerability has been resolved:
btrfs: fix NULL dereference on root when tracing inode eviction
When evicting an inode the first thing we do is to setup tracing for it,
which implies fetching the root's id. But in btrfs_evict_inode() the
root might be NULL, as implied in the next check that we do in
btrfs_evict_inode().
Hence, we either should set the ->root_objectid to 0 in case the root is
NULL, or we move tracing setup after checking that the root is not
NULL. Setting the rootid to 0 at least gives us the possibility to trace
this call even in the case when the root is NULL, so that's the solution
taken here. |
| In the Linux kernel, the following vulnerability has been resolved:
dm-verity: disable recursive forward error correction
There are two problems with the recursive correction:
1. It may cause denial-of-service. In fec_read_bufs, there is a loop that
has 253 iterations. For each iteration, we may call verity_hash_for_block
recursively. There is a limit of 4 nested recursions - that means that
there may be at most 253^4 (4 billion) iterations. Red Hat QE team
actually created an image that pushes dm-verity to this limit - and this
image just makes the udev-worker process get stuck in the 'D' state.
2. It doesn't work. In fec_read_bufs we store data into the variable
"fio->bufs", but fio bufs is shared between recursive invocations, if
"verity_hash_for_block" invoked correction recursively, it would
overwrite partially filled fio->bufs. |
| In the Linux kernel, the following vulnerability has been resolved:
net: dsa: properly keep track of conduit reference
Problem description
-------------------
DSA has a mumbo-jumbo of reference handling of the conduit net device
and its kobject which, sadly, is just wrong and doesn't make sense.
There are two distinct problems.
1. The OF path, which uses of_find_net_device_by_node(), never releases
the elevated refcount on the conduit's kobject. Nominally, the OF and
non-OF paths should result in objects having identical reference
counts taken, and it is already suspicious that
dsa_dev_to_net_device() has a put_device() call which is missing in
dsa_port_parse_of(), but we can actually even verify that an issue
exists. With CONFIG_DEBUG_KOBJECT_RELEASE=y, if we run this command
"before" and "after" applying this patch:
(unbind the conduit driver for net device eno2)
echo 0000:00:00.2 > /sys/bus/pci/drivers/fsl_enetc/unbind
we see these lines in the output diff which appear only with the patch
applied:
kobject: 'eno2' (ffff002009a3a6b8): kobject_release, parent 0000000000000000 (delayed 1000)
kobject: '109' (ffff0020099d59a0): kobject_release, parent 0000000000000000 (delayed 1000)
2. After we find the conduit interface one way (OF) or another (non-OF),
it can get unregistered at any time, and DSA remains with a long-lived,
but in this case stale, cpu_dp->conduit pointer. Holding the net
device's underlying kobject isn't actually of much help, it just
prevents it from being freed (but we never need that kobject
directly). What helps us to prevent the net device from being
unregistered is the parallel netdev reference mechanism (dev_hold()
and dev_put()).
Actually we actually use that netdev tracker mechanism implicitly on
user ports since commit 2f1e8ea726e9 ("net: dsa: link interfaces with
the DSA master to get rid of lockdep warnings"), via netdev_upper_dev_link().
But time still passes at DSA switch probe time between the initial
of_find_net_device_by_node() code and the user port creation time, time
during which the conduit could unregister itself and DSA wouldn't know
about it.
So we have to run of_find_net_device_by_node() under rtnl_lock() to
prevent that from happening, and release the lock only with the netdev
tracker having acquired the reference.
Do we need to keep the reference until dsa_unregister_switch() /
dsa_switch_shutdown()?
1: Maybe yes. A switch device will still be registered even if all user
ports failed to probe, see commit 86f8b1c01a0a ("net: dsa: Do not
make user port errors fatal"), and the cpu_dp->conduit pointers
remain valid. I haven't audited all call paths to see whether they
will actually use the conduit in lack of any user port, but if they
do, it seems safer to not rely on user ports for that reference.
2. Definitely yes. We support changing the conduit which a user port is
associated to, and we can get into a situation where we've moved all
user ports away from a conduit, thus no longer hold any reference to
it via the net device tracker. But we shouldn't let it go nonetheless
- see the next change in relation to dsa_tree_find_first_conduit()
and LAG conduits which disappear.
We have to be prepared to return to the physical conduit, so the CPU
port must explicitly keep another reference to it. This is also to
say: the user ports and their CPU ports may not always keep a
reference to the same conduit net device, and both are needed.
As for the conduit's kobject for the /sys/class/net/ entry, we don't
care about it, we can release it as soon as we hold the net device
object itself.
History and blame attribution
-----------------------------
The code has been refactored so many times, it is very difficult to
follow and properly attribute a blame, but I'll try to make a short
history which I hope to be correct.
We have two distinct probing paths:
- one for OF, introduced in 2016 i
---truncated--- |
| In the Linux kernel, the following vulnerability has been resolved:
ntfs: set dummy blocksize to read boot_block when mounting
When mounting, sb->s_blocksize is used to read the boot_block without
being defined or validated. Set a dummy blocksize before attempting to
read the boot_block.
The issue can be triggered with the following syz reproducer:
mkdirat(0xffffffffffffff9c, &(0x7f0000000080)='./file1\x00', 0x0)
r4 = openat$nullb(0xffffffffffffff9c, &(0x7f0000000040), 0x121403, 0x0)
ioctl$FS_IOC_SETFLAGS(r4, 0x40081271, &(0x7f0000000980)=0x4000)
mount(&(0x7f0000000140)=@nullb, &(0x7f0000000040)='./cgroup\x00',
&(0x7f0000000000)='ntfs3\x00', 0x2208004, 0x0)
syz_clone(0x88200200, 0x0, 0x0, 0x0, 0x0, 0x0)
Here, the ioctl sets the bdev block size to 16384. During mount,
get_tree_bdev_flags() calls sb_set_blocksize(sb, block_size(bdev)),
but since block_size(bdev) > PAGE_SIZE, sb_set_blocksize() leaves
sb->s_blocksize at zero.
Later, ntfs_init_from_boot() attempts to read the boot_block while
sb->s_blocksize is still zero, which triggers the bug.
[almaz.alexandrovich@paragon-software.com: changed comment style, added
return value handling] |
| In the Linux kernel, the following vulnerability has been resolved:
iomap: allocate s_dio_done_wq for async reads as well
Since commit 222f2c7c6d14 ("iomap: always run error completions in user
context"), read error completions are deferred to s_dio_done_wq. This
means the workqueue also needs to be allocated for async reads. |
| In the Linux kernel, the following vulnerability has been resolved:
platform/x86/amd/pmc: Add support for Van Gogh SoC
The ROG Xbox Ally (non-X) SoC features a similar architecture to the
Steam Deck. While the Steam Deck supports S3 (s2idle causes a crash),
this support was dropped by the Xbox Ally which only S0ix suspend.
Since the handler is missing here, this causes the device to not suspend
and the AMD GPU driver to crash while trying to resume afterwards due to
a power hang. |
| In the Linux kernel, the following vulnerability has been resolved:
nvme: fix admin request_queue lifetime
The namespaces can access the controller's admin request_queue, and
stale references on the namespaces may exist after tearing down the
controller. Ensure the admin request_queue is active by moving the
controller's 'put' to after all controller references have been released
to ensure no one is can access the request_queue. This fixes a reported
use-after-free bug:
BUG: KASAN: slab-use-after-free in blk_queue_enter+0x41c/0x4a0
Read of size 8 at addr ffff88c0a53819f8 by task nvme/3287
CPU: 67 UID: 0 PID: 3287 Comm: nvme Tainted: G E 6.13.2-ga1582f1a031e #15
Tainted: [E]=UNSIGNED_MODULE
Hardware name: Jabil /EGS 2S MB1, BIOS 1.00 06/18/2025
Call Trace:
<TASK>
dump_stack_lvl+0x4f/0x60
print_report+0xc4/0x620
? _raw_spin_lock_irqsave+0x70/0xb0
? _raw_read_unlock_irqrestore+0x30/0x30
? blk_queue_enter+0x41c/0x4a0
kasan_report+0xab/0xe0
? blk_queue_enter+0x41c/0x4a0
blk_queue_enter+0x41c/0x4a0
? __irq_work_queue_local+0x75/0x1d0
? blk_queue_start_drain+0x70/0x70
? irq_work_queue+0x18/0x20
? vprintk_emit.part.0+0x1cc/0x350
? wake_up_klogd_work_func+0x60/0x60
blk_mq_alloc_request+0x2b7/0x6b0
? __blk_mq_alloc_requests+0x1060/0x1060
? __switch_to+0x5b7/0x1060
nvme_submit_user_cmd+0xa9/0x330
nvme_user_cmd.isra.0+0x240/0x3f0
? force_sigsegv+0xe0/0xe0
? nvme_user_cmd64+0x400/0x400
? vfs_fileattr_set+0x9b0/0x9b0
? cgroup_update_frozen_flag+0x24/0x1c0
? cgroup_leave_frozen+0x204/0x330
? nvme_ioctl+0x7c/0x2c0
blkdev_ioctl+0x1a8/0x4d0
? blkdev_common_ioctl+0x1930/0x1930
? fdget+0x54/0x380
__x64_sys_ioctl+0x129/0x190
do_syscall_64+0x5b/0x160
entry_SYSCALL_64_after_hwframe+0x4b/0x53
RIP: 0033:0x7f765f703b0b
Code: ff ff ff 85 c0 79 9b 49 c7 c4 ff ff ff ff 5b 5d 4c 89 e0 41 5c c3 66 0f 1f 84 00 00 00 00 00 f3 0f 1e fa b8 10 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d dd 52 0f 00 f7 d8 64 89 01 48
RSP: 002b:00007ffe2cefe808 EFLAGS: 00000202 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007ffe2cefe860 RCX: 00007f765f703b0b
RDX: 00007ffe2cefe860 RSI: 00000000c0484e41 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000003 R09: 0000000000000000
R10: 00007f765f611d50 R11: 0000000000000202 R12: 0000000000000003
R13: 00000000c0484e41 R14: 0000000000000001 R15: 00007ffe2cefea60
</TASK> |
| In the Linux kernel, the following vulnerability has been resolved:
binfmt_misc: restore write access before closing files opened by open_exec()
bm_register_write() opens an executable file using open_exec(), which
internally calls do_open_execat() and denies write access on the file to
avoid modification while it is being executed.
However, when an error occurs, bm_register_write() closes the file using
filp_close() directly. This does not restore the write permission, which
may cause subsequent write operations on the same file to fail.
Fix this by calling exe_file_allow_write_access() before filp_close() to
restore the write permission properly. |
| In the Linux kernel, the following vulnerability has been resolved:
netfilter: nft_ct: add seqadj extension for natted connections
Sequence adjustment may be required for FTP traffic with PASV/EPSV modes.
due to need to re-write packet payload (IP, port) on the ftp control
connection. This can require changes to the TCP length and expected
seq / ack_seq.
The easiest way to reproduce this issue is with PASV mode.
Example ruleset:
table inet ftp_nat {
ct helper ftp_helper {
type "ftp" protocol tcp
l3proto inet
}
chain prerouting {
type filter hook prerouting priority 0; policy accept;
tcp dport 21 ct state new ct helper set "ftp_helper"
}
}
table ip nat {
chain prerouting {
type nat hook prerouting priority -100; policy accept;
tcp dport 21 dnat ip prefix to ip daddr map {
192.168.100.1 : 192.168.13.2/32 }
}
chain postrouting {
type nat hook postrouting priority 100 ; policy accept;
tcp sport 21 snat ip prefix to ip saddr map {
192.168.13.2 : 192.168.100.1/32 }
}
}
Note that the ftp helper gets assigned *after* the dnat setup.
The inverse (nat after helper assign) is handled by an existing
check in nf_nat_setup_info() and will not show the problem.
Topoloy:
+-------------------+ +----------------------------------+
| FTP: 192.168.13.2 | <-> | NAT: 192.168.13.3, 192.168.100.1 |
+-------------------+ +----------------------------------+
|
+-----------------------+
| Client: 192.168.100.2 |
+-----------------------+
ftp nat changes do not work as expected in this case:
Connected to 192.168.100.1.
[..]
ftp> epsv
EPSV/EPRT on IPv4 off.
ftp> ls
227 Entering passive mode (192,168,100,1,209,129).
421 Service not available, remote server has closed connection.
Kernel logs:
Missing nfct_seqadj_ext_add() setup call
WARNING: CPU: 1 PID: 0 at net/netfilter/nf_conntrack_seqadj.c:41
[..]
__nf_nat_mangle_tcp_packet+0x100/0x160 [nf_nat]
nf_nat_ftp+0x142/0x280 [nf_nat_ftp]
help+0x4d1/0x880 [nf_conntrack_ftp]
nf_confirm+0x122/0x2e0 [nf_conntrack]
nf_hook_slow+0x3c/0xb0
..
Fix this by adding the required extension when a conntrack helper is assigned
to a connection that has a nat binding. |
| In the Linux kernel, the following vulnerability has been resolved:
riscv: stacktrace: Disable KASAN checks for non-current tasks
Unwinding the stack of a task other than current, KASAN would report
"BUG: KASAN: out-of-bounds in walk_stackframe+0x41c/0x460"
There is a same issue on x86 and has been resolved by the commit
84936118bdf3 ("x86/unwind: Disable KASAN checks for non-current tasks")
The solution could be applied to RISC-V too.
This patch also can solve the issue:
https://seclists.org/oss-sec/2025/q4/23
[pjw@kernel.org: clean up checkpatch issues] |
| In the Linux kernel, the following vulnerability has been resolved:
nvme: nvme-fc: Ensure ->ioerr_work is cancelled in nvme_fc_delete_ctrl()
nvme_fc_delete_assocation() waits for pending I/O to complete before
returning, and an error can cause ->ioerr_work to be queued after
cancel_work_sync() had been called. Move the call to cancel_work_sync() to
be after nvme_fc_delete_association() to ensure ->ioerr_work is not running
when the nvme_fc_ctrl object is freed. Otherwise the following can occur:
[ 1135.911754] list_del corruption, ff2d24c8093f31f8->next is NULL
[ 1135.917705] ------------[ cut here ]------------
[ 1135.922336] kernel BUG at lib/list_debug.c:52!
[ 1135.926784] Oops: invalid opcode: 0000 [#1] SMP NOPTI
[ 1135.931851] CPU: 48 UID: 0 PID: 726 Comm: kworker/u449:23 Kdump: loaded Not tainted 6.12.0 #1 PREEMPT(voluntary)
[ 1135.943490] Hardware name: Dell Inc. PowerEdge R660/0HGTK9, BIOS 2.5.4 01/16/2025
[ 1135.950969] Workqueue: 0x0 (nvme-wq)
[ 1135.954673] RIP: 0010:__list_del_entry_valid_or_report.cold+0xf/0x6f
[ 1135.961041] Code: c7 c7 98 68 72 94 e8 26 45 fe ff 0f 0b 48 c7 c7 70 68 72 94 e8 18 45 fe ff 0f 0b 48 89 fe 48 c7 c7 80 69 72 94 e8 07 45 fe ff <0f> 0b 48 89 d1 48 c7 c7 a0 6a 72 94 48 89 c2 e8 f3 44 fe ff 0f 0b
[ 1135.979788] RSP: 0018:ff579b19482d3e50 EFLAGS: 00010046
[ 1135.985015] RAX: 0000000000000033 RBX: ff2d24c8093f31f0 RCX: 0000000000000000
[ 1135.992148] RDX: 0000000000000000 RSI: ff2d24d6bfa1d0c0 RDI: ff2d24d6bfa1d0c0
[ 1135.999278] RBP: ff2d24c8093f31f8 R08: 0000000000000000 R09: ffffffff951e2b08
[ 1136.006413] R10: ffffffff95122ac8 R11: 0000000000000003 R12: ff2d24c78697c100
[ 1136.013546] R13: fffffffffffffff8 R14: 0000000000000000 R15: ff2d24c78697c0c0
[ 1136.020677] FS: 0000000000000000(0000) GS:ff2d24d6bfa00000(0000) knlGS:0000000000000000
[ 1136.028765] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 1136.034510] CR2: 00007fd207f90b80 CR3: 000000163ea22003 CR4: 0000000000f73ef0
[ 1136.041641] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 1136.048776] DR3: 0000000000000000 DR6: 00000000fffe07f0 DR7: 0000000000000400
[ 1136.055910] PKRU: 55555554
[ 1136.058623] Call Trace:
[ 1136.061074] <TASK>
[ 1136.063179] ? show_trace_log_lvl+0x1b0/0x2f0
[ 1136.067540] ? show_trace_log_lvl+0x1b0/0x2f0
[ 1136.071898] ? move_linked_works+0x4a/0xa0
[ 1136.075998] ? __list_del_entry_valid_or_report.cold+0xf/0x6f
[ 1136.081744] ? __die_body.cold+0x8/0x12
[ 1136.085584] ? die+0x2e/0x50
[ 1136.088469] ? do_trap+0xca/0x110
[ 1136.091789] ? do_error_trap+0x65/0x80
[ 1136.095543] ? __list_del_entry_valid_or_report.cold+0xf/0x6f
[ 1136.101289] ? exc_invalid_op+0x50/0x70
[ 1136.105127] ? __list_del_entry_valid_or_report.cold+0xf/0x6f
[ 1136.110874] ? asm_exc_invalid_op+0x1a/0x20
[ 1136.115059] ? __list_del_entry_valid_or_report.cold+0xf/0x6f
[ 1136.120806] move_linked_works+0x4a/0xa0
[ 1136.124733] worker_thread+0x216/0x3a0
[ 1136.128485] ? __pfx_worker_thread+0x10/0x10
[ 1136.132758] kthread+0xfa/0x240
[ 1136.135904] ? __pfx_kthread+0x10/0x10
[ 1136.139657] ret_from_fork+0x31/0x50
[ 1136.143236] ? __pfx_kthread+0x10/0x10
[ 1136.146988] ret_from_fork_asm+0x1a/0x30
[ 1136.150915] </TASK> |
| In the Linux kernel, the following vulnerability has been resolved:
f2fs: fix to avoid migrating empty section
It reports a bug from device w/ zufs:
F2FS-fs (dm-64): Inconsistent segment (173822) type [1, 0] in SSA and SIT
F2FS-fs (dm-64): Stopped filesystem due to reason: 4
Thread A Thread B
- f2fs_expand_inode_data
- f2fs_allocate_pinning_section
- f2fs_gc_range
- do_garbage_collect w/ segno #x
- writepage
- f2fs_allocate_data_block
- new_curseg
- allocate segno #x
The root cause is: fallocate on pinning file may race w/ block allocation
as above, result in do_garbage_collect() from fallocate() may migrate
segment which is just allocated by a log, the log will update segment type
in its in-memory structure, however GC will get segment type from on-disk
SSA block, once segment type changes by log, we can detect such
inconsistency, then shutdown filesystem.
In this case, on-disk SSA shows type of segno #173822 is 1 (SUM_TYPE_NODE),
however segno #173822 was just allocated as data type segment, so in-memory
SIT shows type of segno #173822 is 0 (SUM_TYPE_DATA).
Change as below to fix this issue:
- check whether current section is empty before gc
- add sanity checks on do_garbage_collect() to avoid any race case, result
in migrating segment used by log.
- btw, it fixes misc issue in printed logs: "SSA and SIT" -> "SIT and SSA". |
| In the Linux kernel, the following vulnerability has been resolved:
blk-throttle: fix access race during throttle policy activation
On repeated cold boots we occasionally hit a NULL pointer crash in
blk_should_throtl() when throttling is consulted before the throttle
policy is fully enabled for the queue. Checking only q->td != NULL is
insufficient during early initialization, so blkg_to_pd() for the
throttle policy can still return NULL and blkg_to_tg() becomes NULL,
which later gets dereferenced.
Unable to handle kernel NULL pointer dereference
at virtual address 0000000000000156
...
pc : submit_bio_noacct+0x14c/0x4c8
lr : submit_bio_noacct+0x48/0x4c8
sp : ffff800087f0b690
x29: ffff800087f0b690 x28: 0000000000005f90 x27: ffff00068af393c0
x26: 0000000000080000 x25: 000000000002fbc0 x24: ffff000684ddcc70
x23: 0000000000000000 x22: 0000000000000000 x21: 0000000000000000
x20: 0000000000080000 x19: ffff000684ddcd08 x18: ffffffffffffffff
x17: 0000000000000000 x16: ffff80008132a550 x15: 0000ffff98020fff
x14: 0000000000000000 x13: 1fffe000d11d7021 x12: ffff000688eb810c
x11: ffff00077ec4bb80 x10: ffff000688dcb720 x9 : ffff80008068ef60
x8 : 00000a6fb8a86e85 x7 : 000000000000111e x6 : 0000000000000002
x5 : 0000000000000246 x4 : 0000000000015cff x3 : 0000000000394500
x2 : ffff000682e35e40 x1 : 0000000000364940 x0 : 000000000000001a
Call trace:
submit_bio_noacct+0x14c/0x4c8
verity_map+0x178/0x2c8
__map_bio+0x228/0x250
dm_submit_bio+0x1c4/0x678
__submit_bio+0x170/0x230
submit_bio_noacct_nocheck+0x16c/0x388
submit_bio_noacct+0x16c/0x4c8
submit_bio+0xb4/0x210
f2fs_submit_read_bio+0x4c/0xf0
f2fs_mpage_readpages+0x3b0/0x5f0
f2fs_readahead+0x90/0xe8
Tighten blk_throtl_activated() to also require that the throttle policy
bit is set on the queue:
return q->td != NULL &&
test_bit(blkcg_policy_throtl.plid, q->blkcg_pols);
This prevents blk_should_throtl() from accessing throttle group state
until policy data has been attached to blkgs. |
| In the Linux kernel, the following vulnerability has been resolved:
ipv6: use RCU in ip6_xmit()
Use RCU in ip6_xmit() in order to use dst_dev_rcu() to prevent
possible UAF. |
| In the Linux kernel, the following vulnerability has been resolved:
spi: cadence-quadspi: Implement refcount to handle unbind during busy
driver support indirect read and indirect write operation with
assumption no force device removal(unbind) operation. However
force device removal(removal) is still available to root superuser.
Unbinding driver during operation causes kernel crash. This changes
ensure driver able to handle such operation for indirect read and
indirect write by implementing refcount to track attached devices
to the controller and gracefully wait and until attached devices
remove operation completed before proceed with removal operation. |
| In the Linux kernel, the following vulnerability has been resolved:
wifi: brcmfmac: fix use-after-free when rescheduling brcmf_btcoex_info work
The brcmf_btcoex_detach() only shuts down the btcoex timer, if the
flag timer_on is false. However, the brcmf_btcoex_timerfunc(), which
runs as timer handler, sets timer_on to false. This creates critical
race conditions:
1.If brcmf_btcoex_detach() is called while brcmf_btcoex_timerfunc()
is executing, it may observe timer_on as false and skip the call to
timer_shutdown_sync().
2.The brcmf_btcoex_timerfunc() may then reschedule the brcmf_btcoex_info
worker after the cancel_work_sync() has been executed, resulting in
use-after-free bugs.
The use-after-free bugs occur in two distinct scenarios, depending on
the timing of when the brcmf_btcoex_info struct is freed relative to
the execution of its worker thread.
Scenario 1: Freed before the worker is scheduled
The brcmf_btcoex_info is deallocated before the worker is scheduled.
A race condition can occur when schedule_work(&bt_local->work) is
called after the target memory has been freed. The sequence of events
is detailed below:
CPU0 | CPU1
brcmf_btcoex_detach | brcmf_btcoex_timerfunc
| bt_local->timer_on = false;
if (cfg->btcoex->timer_on) |
... |
cancel_work_sync(); |
... |
kfree(cfg->btcoex); // FREE |
| schedule_work(&bt_local->work); // USE
Scenario 2: Freed after the worker is scheduled
The brcmf_btcoex_info is freed after the worker has been scheduled
but before or during its execution. In this case, statements within
the brcmf_btcoex_handler() — such as the container_of macro and
subsequent dereferences of the brcmf_btcoex_info object will cause
a use-after-free access. The following timeline illustrates this
scenario:
CPU0 | CPU1
brcmf_btcoex_detach | brcmf_btcoex_timerfunc
| bt_local->timer_on = false;
if (cfg->btcoex->timer_on) |
... |
cancel_work_sync(); |
... | schedule_work(); // Reschedule
|
kfree(cfg->btcoex); // FREE | brcmf_btcoex_handler() // Worker
/* | btci = container_of(....); // USE
The kfree() above could | ...
also occur at any point | btci-> // USE
during the worker's execution|
*/ |
To resolve the race conditions, drop the conditional check and call
timer_shutdown_sync() directly. It can deactivate the timer reliably,
regardless of its current state. Once stopped, the timer_on state is
then set to false. |
| 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:
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. |
