In the Linux kernel, the following vulnerability has been resolved:
dm cache: Fix UAF in destroy()
Dm_cache also has the same UAF problem when dm_resume()
and dm_destroy() are concurrent.
Therefore, cancelling timer again in destroy().
In the Linux kernel, the following vulnerability has been resolved:
binfmt_misc: fix shift-out-of-bounds in check_special_flags
UBSAN reported a shift-out-of-bounds warning:
left shift of 1 by 31 places cannot be represented in type 'int'
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x8d/0xcf lib/dump_stack.c:106
ubsan_epilogue+0xa/0x44 lib/ubsan.c:151
__ubsan_handle_shift_out_of_bounds+0x1e7/0x208 lib/ubsan.c:322
check_special_flags fs/binfmt_misc.c:241 [inline]
create_entry fs/binfmt_misc.c:456 [inline]
bm_register_write+0x9d3/0xa20 fs/binfmt_misc.c:654
vfs_write+0x11e/0x580 fs/read_write.c:582
ksys_write+0xcf/0x120 fs/read_write.c:637
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x34/0x80 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x4194e1
Since the type of Node's flags is unsigned long, we should define these
macros with same type too.
In the Linux kernel, the following vulnerability has been resolved:
eth: alx: take rtnl_lock on resume
Zbynek reports that alx trips an rtnl assertion on resume:
RTNL: assertion failed at net/core/dev.c (2891)
RIP: 0010:netif_set_real_num_tx_queues+0x1ac/0x1c0
Call Trace:
<TASK>
__alx_open+0x230/0x570 [alx]
alx_resume+0x54/0x80 [alx]
? pci_legacy_resume+0x80/0x80
dpm_run_callback+0x4a/0x150
device_resume+0x8b/0x190
async_resume+0x19/0x30
async_run_entry_fn+0x30/0x130
process_one_work+0x1e5/0x3b0
indeed the driver does not hold rtnl_lock during its internal close
and re-open functions during suspend/resume. Note that this is not
a huge bug as the driver implements its own locking, and does not
implement changing the number of queues, but we need to silence
the splat.
In the Linux kernel, the following vulnerability has been resolved:
net: enetc: avoid buffer leaks on xdp_do_redirect() failure
Before enetc_clean_rx_ring_xdp() calls xdp_do_redirect(), each software
BD in the RX ring between index orig_i and i can have one of 2 refcount
values on its page.
We are the owner of the current buffer that is being processed, so the
refcount will be at least 1.
If the current owner of the buffer at the diametrically opposed index
in the RX ring (i.o.w, the other half of this page) has not yet called
kfree(), this page's refcount could even be 2.
enetc_page_reusable() in enetc_flip_rx_buff() tests for the page
refcount against 1, and [ if it's 2 ] does not attempt to reuse it.
But if enetc_flip_rx_buff() is put after the xdp_do_redirect() call,
the page refcount can have one of 3 values. It can also be 0, if there
is no owner of the other page half, and xdp_do_redirect() for this
buffer ran so far that it triggered a flush of the devmap/cpumap bulk
queue, and the consumers of those bulk queues also freed the buffer,
all by the time xdp_do_redirect() returns the execution back to enetc.
This is the reason why enetc_flip_rx_buff() is called before
xdp_do_redirect(), but there is a big flaw with that reasoning:
enetc_flip_rx_buff() will set rx_swbd->page = NULL on both sides of the
enetc_page_reusable() branch, and if xdp_do_redirect() returns an error,
we call enetc_xdp_free(), which does not deal gracefully with that.
In fact, what happens is quite special. The page refcounts start as 1.
enetc_flip_rx_buff() figures they're reusable, transfers these
rx_swbd->page pointers to a different rx_swbd in enetc_reuse_page(), and
bumps the refcount to 2. When xdp_do_redirect() later returns an error,
we call the no-op enetc_xdp_free(), but we still haven't lost the
reference to that page. A copy of it is still at rx_ring->next_to_alloc,
but that has refcount 2 (and there are no concurrent owners of it in
flight, to drop the refcount). What really kills the system is when
we'll flip the rx_swbd->page the second time around. With an updated
refcount of 2, the page will not be reusable and we'll really leak it.
Then enetc_new_page() will have to allocate more pages, which will then
eventually leak again on further errors from xdp_do_redirect().
The problem, summarized, is that we zeroize rx_swbd->page before we're
completely done with it, and this makes it impossible for the error path
to do something with it.
Since the packet is potentially multi-buffer and therefore the
rx_swbd->page is potentially an array, manual passing of the old
pointers between enetc_flip_rx_buff() and enetc_xdp_free() is a bit
difficult.
For the sake of going with a simple solution, we accept the possibility
of racing with xdp_do_redirect(), and we move the flip procedure to
execute only on the redirect success path. By racing, I mean that the
page may be deemed as not reusable by enetc (having a refcount of 0),
but there will be no leak in that case, either.
Once we accept that, we have something better to do with buffers on
XDP_REDIRECT failure. Since we haven't performed half-page flipping yet,
we won't, either (and this way, we can avoid enetc_xdp_free()
completely, which gives the entire page to the slab allocator).
Instead, we'll call enetc_xdp_drop(), which will recycle this half of
the buffer back to the RX ring.
In the Linux kernel, the following vulnerability has been resolved:
ALSA: usb-audio: Fix potential memory leaks
When the driver hits -ENOMEM at allocating a URB or a buffer, it
aborts and goes to the error path that releases the all previously
allocated resources. However, when -ENOMEM hits at the middle of the
sync EP URB allocation loop, the partially allocated URBs might be
left without released, because ep->nurbs is still zero at that point.
Fix it by setting ep->nurbs at first, so that the error handler loops
over the full URB list.
In the Linux kernel, the following vulnerability has been resolved:
ext4: add EXT4_IGET_BAD flag to prevent unexpected bad inode
There are many places that will get unhappy (and crash) when ext4_iget()
returns a bad inode. However, if iget the boot loader inode, allows a bad
inode to be returned, because the inode may not be initialized. This
mechanism can be used to bypass some checks and cause panic. To solve this
problem, we add a special iget flag EXT4_IGET_BAD. Only with this flag
we'd be returning bad inode from ext4_iget(), otherwise we always return
the error code if the inode is bad inode.(suggested by Jan Kara)
In the Linux kernel, the following vulnerability has been resolved:
net: ethernet: ti: Fix return type of netcp_ndo_start_xmit()
With clang's kernel control flow integrity (kCFI, CONFIG_CFI_CLANG),
indirect call targets are validated against the expected function
pointer prototype to make sure the call target is valid to help mitigate
ROP attacks. If they are not identical, there is a failure at run time,
which manifests as either a kernel panic or thread getting killed. A
proposed warning in clang aims to catch these at compile time, which
reveals:
drivers/net/ethernet/ti/netcp_core.c:1944:21: error: incompatible function pointer types initializing 'netdev_tx_t (*)(struct sk_buff *, struct net_device *)' (aka 'enum netdev_tx (*)(struct sk_buff *, struct net_device *)') with an expression of type 'int (struct sk_buff *, struct net_device *)' [-Werror,-Wincompatible-function-pointer-types-strict]
.ndo_start_xmit = netcp_ndo_start_xmit,
^~~~~~~~~~~~~~~~~~~~
1 error generated.
->ndo_start_xmit() in 'struct net_device_ops' expects a return type of
'netdev_tx_t', not 'int'. Adjust the return type of
netcp_ndo_start_xmit() to match the prototype's to resolve the warning
and CFI failure.
In the Linux kernel, the following vulnerability has been resolved:
block, bfq: fix possible uaf for 'bfqq->bic'
Our test report a uaf for 'bfqq->bic' in 5.10:
==================================================================
BUG: KASAN: use-after-free in bfq_select_queue+0x378/0xa30
CPU: 6 PID: 2318352 Comm: fsstress Kdump: loaded Not tainted 5.10.0-60.18.0.50.h602.kasan.eulerosv2r11.x86_64 #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.1-0-ga5cab58-20220320_160524-szxrtosci10000 04/01/2014
Call Trace:
bfq_select_queue+0x378/0xa30
bfq_dispatch_request+0xe8/0x130
blk_mq_do_dispatch_sched+0x62/0xb0
__blk_mq_sched_dispatch_requests+0x215/0x2a0
blk_mq_sched_dispatch_requests+0x8f/0xd0
__blk_mq_run_hw_queue+0x98/0x180
__blk_mq_delay_run_hw_queue+0x22b/0x240
blk_mq_run_hw_queue+0xe3/0x190
blk_mq_sched_insert_requests+0x107/0x200
blk_mq_flush_plug_list+0x26e/0x3c0
blk_finish_plug+0x63/0x90
__iomap_dio_rw+0x7b5/0x910
iomap_dio_rw+0x36/0x80
ext4_dio_read_iter+0x146/0x190 [ext4]
ext4_file_read_iter+0x1e2/0x230 [ext4]
new_sync_read+0x29f/0x400
vfs_read+0x24e/0x2d0
ksys_read+0xd5/0x1b0
do_syscall_64+0x33/0x40
entry_SYSCALL_64_after_hwframe+0x61/0xc6
Commit 3bc5e683c67d ("bfq: Split shared queues on move between cgroups")
changes that move process to a new cgroup will allocate a new bfqq to
use, however, the old bfqq and new bfqq can point to the same bic:
1) Initial state, two process with io in the same cgroup.
Process 1 Process 2
(BIC1) (BIC2)
| Λ | Λ
| | | |
V | V |
bfqq1 bfqq2
2) bfqq1 is merged to bfqq2.
Process 1 Process 2
(BIC1) (BIC2)
| |
\-------------\|
V
bfqq1 bfqq2(coop)
3) Process 1 exit, then issue new io(denoce IOA) from Process 2.
(BIC2)
| Λ
| |
V |
bfqq2(coop)
4) Before IOA is completed, move Process 2 to another cgroup and issue io.
Process 2
(BIC2)
Λ
|\--------------\
| V
bfqq2 bfqq3
Now that BIC2 points to bfqq3, while bfqq2 and bfqq3 both point to BIC2.
If all the requests are completed, and Process 2 exit, BIC2 will be
freed while there is no guarantee that bfqq2 will be freed before BIC2.
Fix the problem by clearing bfqq->bic while bfqq is detached from bic.
In the Linux kernel, the following vulnerability has been resolved:
drm/mipi-dsi: Detach devices when removing the host
Whenever the MIPI-DSI host is unregistered, the code of
mipi_dsi_host_unregister() loops over every device currently found on that
bus and will unregister it.
However, it doesn't detach it from the bus first, which leads to all kind
of resource leaks if the host wants to perform some clean up whenever a
device is detached.
In the Linux kernel, the following vulnerability has been resolved:
bpf: Propagate error from htab_lock_bucket() to userspace
In __htab_map_lookup_and_delete_batch() if htab_lock_bucket() returns
-EBUSY, it will go to next bucket. Going to next bucket may not only
skip the elements in current bucket silently, but also incur
out-of-bound memory access or expose kernel memory to userspace if
current bucket_cnt is greater than bucket_size or zero.
Fixing it by stopping batch operation and returning -EBUSY when
htab_lock_bucket() fails, and the application can retry or skip the busy
batch as needed.