Security Vulnerabilities
- CVEs Published In 2024
In the Linux kernel, the following vulnerability has been resolved:
ksmbd: fix use-after-free in SMB request handling
A race condition exists between SMB request handling in
`ksmbd_conn_handler_loop()` and the freeing of `ksmbd_conn` in the
workqueue handler `handle_ksmbd_work()`. This leads to a UAF.
- KASAN: slab-use-after-free Read in handle_ksmbd_work
- KASAN: slab-use-after-free in rtlock_slowlock_locked
This race condition arises as follows:
- `ksmbd_conn_handler_loop()` waits for `conn->r_count` to reach zero:
`wait_event(conn->r_count_q, atomic_read(&conn->r_count) == 0);`
- Meanwhile, `handle_ksmbd_work()` decrements `conn->r_count` using
`atomic_dec_return(&conn->r_count)`, and if it reaches zero, calls
`ksmbd_conn_free()`, which frees `conn`.
- However, after `handle_ksmbd_work()` decrements `conn->r_count`,
it may still access `conn->r_count_q` in the following line:
`waitqueue_active(&conn->r_count_q)` or `wake_up(&conn->r_count_q)`
This results in a UAF, as `conn` has already been freed.
The discovery of this UAF can be referenced in the following PR for
syzkaller's support for SMB requests.
In the Linux kernel, the following vulnerability has been resolved:
io_uring: check for overflows in io_pin_pages
WARNING: CPU: 0 PID: 5834 at io_uring/memmap.c:144 io_pin_pages+0x149/0x180 io_uring/memmap.c:144
CPU: 0 UID: 0 PID: 5834 Comm: syz-executor825 Not tainted 6.12.0-next-20241118-syzkaller #0
Call Trace:
<TASK>
__io_uaddr_map+0xfb/0x2d0 io_uring/memmap.c:183
io_rings_map io_uring/io_uring.c:2611 [inline]
io_allocate_scq_urings+0x1c0/0x650 io_uring/io_uring.c:3470
io_uring_create+0x5b5/0xc00 io_uring/io_uring.c:3692
io_uring_setup io_uring/io_uring.c:3781 [inline]
...
</TASK>
io_pin_pages()'s uaddr parameter came directly from the user and can be
garbage. Don't just add size to it as it can overflow.
In the Linux kernel, the following vulnerability has been resolved:
wifi: ath12k: fix crash when unbinding
If there is an error during some initialization related to firmware,
the function ath12k_dp_cc_cleanup is called to release resources.
However this is released again when the device is unbinded (ath12k_pci),
and we get:
BUG: kernel NULL pointer dereference, address: 0000000000000020
at RIP: 0010:ath12k_dp_cc_cleanup.part.0+0xb6/0x500 [ath12k]
Call Trace:
ath12k_dp_cc_cleanup
ath12k_dp_free
ath12k_core_deinit
ath12k_pci_remove
...
The issue is always reproducible from a VM because the MSI addressing
initialization is failing.
In order to fix the issue, just set to NULL the released structure in
ath12k_dp_cc_cleanup at the end.
In the Linux kernel, the following vulnerability has been resolved:
wifi: nl80211: fix bounds checker error in nl80211_parse_sched_scan
The channels array in the cfg80211_scan_request has a __counted_by
attribute attached to it, which points to the n_channels variable. This
attribute is used in bounds checking, and if it is not set before the
array is filled, then the bounds sanitizer will issue a warning or a
kernel panic if CONFIG_UBSAN_TRAP is set.
This patch sets the size of allocated memory as the initial value for
n_channels. It is updated with the actual number of added elements after
the array is filled.
In the Linux kernel, the following vulnerability has been resolved:
wifi: rtlwifi: Drastically reduce the attempts to read efuse in case of failures
Syzkaller reported a hung task with uevent_show() on stack trace. That
specific issue was addressed by another commit [0], but even with that
fix applied (for example, running v6.12-rc5) we face another type of hung
task that comes from the same reproducer [1]. By investigating that, we
could narrow it to the following path:
(a) Syzkaller emulates a Realtek USB WiFi adapter using raw-gadget and
dummy_hcd infrastructure.
(b) During the probe of rtl8192cu, the driver ends-up performing an efuse
read procedure (which is related to EEPROM load IIUC), and here lies the
issue: the function read_efuse() calls read_efuse_byte() many times, as
loop iterations depending on the efuse size (in our example, 512 in total).
This procedure for reading efuse bytes relies in a loop that performs an
I/O read up to *10k* times in case of failures. We measured the time of
the loop inside read_efuse_byte() alone, and in this reproducer (which
involves the dummy_hcd emulation layer), it takes 15 seconds each. As a
consequence, we have the driver stuck in its probe routine for big time,
exposing a stack trace like below if we attempt to reboot the system, for
example:
task:kworker/0:3 state:D stack:0 pid:662 tgid:662 ppid:2 flags:0x00004000
Workqueue: usb_hub_wq hub_event
Call Trace:
__schedule+0xe22/0xeb6
schedule_timeout+0xe7/0x132
__wait_for_common+0xb5/0x12e
usb_start_wait_urb+0xc5/0x1ef
? usb_alloc_urb+0x95/0xa4
usb_control_msg+0xff/0x184
_usbctrl_vendorreq_sync+0xa0/0x161
_usb_read_sync+0xb3/0xc5
read_efuse_byte+0x13c/0x146
read_efuse+0x351/0x5f0
efuse_read_all_map+0x42/0x52
rtl_efuse_shadow_map_update+0x60/0xef
rtl_get_hwinfo+0x5d/0x1c2
rtl92cu_read_eeprom_info+0x10a/0x8d5
? rtl92c_read_chip_version+0x14f/0x17e
rtl_usb_probe+0x323/0x851
usb_probe_interface+0x278/0x34b
really_probe+0x202/0x4a4
__driver_probe_device+0x166/0x1b2
driver_probe_device+0x2f/0xd8
[...]
We propose hereby to drastically reduce the attempts of doing the I/O
reads in case of failures, restricted to USB devices (given that
they're inherently slower than PCIe ones). By retrying up to 10 times
(instead of 10000), we got reponsiveness in the reproducer, while seems
reasonable to believe that there's no sane USB device implementation in
the field requiring this amount of retries at every I/O read in order
to properly work. Based on that assumption, it'd be good to have it
backported to stable but maybe not since driver implementation (the 10k
number comes from day 0), perhaps up to 6.x series makes sense.
[0] Commit 15fffc6a5624 ("driver core: Fix uevent_show() vs driver detach race")
[1] A note about that: this syzkaller report presents multiple reproducers
that differs by the type of emulated USB device. For this specific case,
check the entry from 2024/08/08 06:23 in the list of crashes; the C repro
is available at https://syzkaller.appspot.com/text?tag=ReproC&x=1521fc83980000.
In the Linux kernel, the following vulnerability has been resolved:
wifi: ath12k: fix warning when unbinding
If there is an error during some initialization related to firmware,
the buffers dp->tx_ring[i].tx_status are released.
However this is released again when the device is unbinded (ath12k_pci),
and we get:
WARNING: CPU: 0 PID: 2098 at mm/slub.c:4689 free_large_kmalloc+0x4d/0x80
Call Trace:
free_large_kmalloc
ath12k_dp_free
ath12k_core_deinit
ath12k_pci_remove
...
The issue is always reproducible from a VM because the MSI addressing
initialization is failing.
In order to fix the issue, just set the buffers to NULL after releasing in
order to avoid the double free.
In the Linux kernel, the following vulnerability has been resolved:
clk: clk-loongson2: Fix potential buffer overflow in flexible-array member access
Flexible-array member `hws` in `struct clk_hw_onecell_data` is annotated
with the `counted_by()` attribute. This means that when memory is
allocated for this array, the _counter_, which in this case is member
`num` in the flexible structure, should be set to the maximum number of
elements the flexible array can contain, or fewer.
In this case, the total number of elements for the flexible array is
determined by variable `clks_num` when allocating heap space via
`devm_kzalloc()`, as shown below:
289 struct loongson2_clk_provider *clp;
...
296 for (p = data; p->name; p++)
297 clks_num++;
298
299 clp = devm_kzalloc(dev, struct_size(clp, clk_data.hws, clks_num),
300 GFP_KERNEL);
So, `clp->clk_data.num` should be set to `clks_num` or less, and not
exceed `clks_num`, as is currently the case. Otherwise, if data is
written into `clp->clk_data.hws[clks_num]`, the instrumentation
provided by the compiler won't detect the overflow, leading to a
memory corruption bug at runtime.
Fix this issue by setting `clp->clk_data.num` to `clks_num`.
In the Linux kernel, the following vulnerability has been resolved:
clk: clk-loongson2: Fix memory corruption bug in struct loongson2_clk_provider
Some heap space is allocated for the flexible structure `struct
clk_hw_onecell_data` and its flexible-array member `hws` through
the composite structure `struct loongson2_clk_provider` in function
`loongson2_clk_probe()`, as shown below:
289 struct loongson2_clk_provider *clp;
...
296 for (p = data; p->name; p++)
297 clks_num++;
298
299 clp = devm_kzalloc(dev, struct_size(clp, clk_data.hws, clks_num),
300 GFP_KERNEL);
Then some data is written into the flexible array:
350 clp->clk_data.hws[p->id] = hw;
This corrupts `clk_lock`, which is the spinlock variable immediately
following the `clk_data` member in `struct loongson2_clk_provider`:
struct loongson2_clk_provider {
void __iomem *base;
struct device *dev;
struct clk_hw_onecell_data clk_data;
spinlock_t clk_lock; /* protect access to DIV registers */
};
The problem is that the flexible structure is currently placed in the
middle of `struct loongson2_clk_provider` instead of at the end.
Fix this by moving `struct clk_hw_onecell_data clk_data;` to the end of
`struct loongson2_clk_provider`. Also, add a code comment to help
prevent this from happening again in case new members are added to the
structure in the future.
This change also fixes the following -Wflex-array-member-not-at-end
warning:
drivers/clk/clk-loongson2.c:32:36: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]
In the Linux kernel, the following vulnerability has been resolved:
smb: prevent use-after-free due to open_cached_dir error paths
If open_cached_dir() encounters an error parsing the lease from the
server, the error handling may race with receiving a lease break,
resulting in open_cached_dir() freeing the cfid while the queued work is
pending.
Update open_cached_dir() to drop refs rather than directly freeing the
cfid.
Have cached_dir_lease_break(), cfids_laundromat_worker(), and
invalidate_all_cached_dirs() clear has_lease immediately while still
holding cfids->cfid_list_lock, and then use this to also simplify the
reference counting in cfids_laundromat_worker() and
invalidate_all_cached_dirs().
Fixes this KASAN splat (which manually injects an error and lease break
in open_cached_dir()):
==================================================================
BUG: KASAN: slab-use-after-free in smb2_cached_lease_break+0x27/0xb0
Read of size 8 at addr ffff88811cc24c10 by task kworker/3:1/65
CPU: 3 UID: 0 PID: 65 Comm: kworker/3:1 Not tainted 6.12.0-rc6-g255cf264e6e5-dirty #87
Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 11/12/2020
Workqueue: cifsiod smb2_cached_lease_break
Call Trace:
<TASK>
dump_stack_lvl+0x77/0xb0
print_report+0xce/0x660
kasan_report+0xd3/0x110
smb2_cached_lease_break+0x27/0xb0
process_one_work+0x50a/0xc50
worker_thread+0x2ba/0x530
kthread+0x17c/0x1c0
ret_from_fork+0x34/0x60
ret_from_fork_asm+0x1a/0x30
</TASK>
Allocated by task 2464:
kasan_save_stack+0x33/0x60
kasan_save_track+0x14/0x30
__kasan_kmalloc+0xaa/0xb0
open_cached_dir+0xa7d/0x1fb0
smb2_query_path_info+0x43c/0x6e0
cifs_get_fattr+0x346/0xf10
cifs_get_inode_info+0x157/0x210
cifs_revalidate_dentry_attr+0x2d1/0x460
cifs_getattr+0x173/0x470
vfs_statx_path+0x10f/0x160
vfs_statx+0xe9/0x150
vfs_fstatat+0x5e/0xc0
__do_sys_newfstatat+0x91/0xf0
do_syscall_64+0x95/0x1a0
entry_SYSCALL_64_after_hwframe+0x76/0x7e
Freed by task 2464:
kasan_save_stack+0x33/0x60
kasan_save_track+0x14/0x30
kasan_save_free_info+0x3b/0x60
__kasan_slab_free+0x51/0x70
kfree+0x174/0x520
open_cached_dir+0x97f/0x1fb0
smb2_query_path_info+0x43c/0x6e0
cifs_get_fattr+0x346/0xf10
cifs_get_inode_info+0x157/0x210
cifs_revalidate_dentry_attr+0x2d1/0x460
cifs_getattr+0x173/0x470
vfs_statx_path+0x10f/0x160
vfs_statx+0xe9/0x150
vfs_fstatat+0x5e/0xc0
__do_sys_newfstatat+0x91/0xf0
do_syscall_64+0x95/0x1a0
entry_SYSCALL_64_after_hwframe+0x76/0x7e
Last potentially related work creation:
kasan_save_stack+0x33/0x60
__kasan_record_aux_stack+0xad/0xc0
insert_work+0x32/0x100
__queue_work+0x5c9/0x870
queue_work_on+0x82/0x90
open_cached_dir+0x1369/0x1fb0
smb2_query_path_info+0x43c/0x6e0
cifs_get_fattr+0x346/0xf10
cifs_get_inode_info+0x157/0x210
cifs_revalidate_dentry_attr+0x2d1/0x460
cifs_getattr+0x173/0x470
vfs_statx_path+0x10f/0x160
vfs_statx+0xe9/0x150
vfs_fstatat+0x5e/0xc0
__do_sys_newfstatat+0x91/0xf0
do_syscall_64+0x95/0x1a0
entry_SYSCALL_64_after_hwframe+0x76/0x7e
The buggy address belongs to the object at ffff88811cc24c00
which belongs to the cache kmalloc-1k of size 1024
The buggy address is located 16 bytes inside of
freed 1024-byte region [ffff88811cc24c00, ffff88811cc25000)
In the Linux kernel, the following vulnerability has been resolved:
smb: Don't leak cfid when reconnect races with open_cached_dir
open_cached_dir() may either race with the tcon reconnection even before
compound_send_recv() or directly trigger a reconnection via
SMB2_open_init() or SMB_query_info_init().
The reconnection process invokes invalidate_all_cached_dirs() via
cifs_mark_open_files_invalid(), which removes all cfids from the
cfids->entries list but doesn't drop a ref if has_lease isn't true. This
results in the currently-being-constructed cfid not being on the list,
but still having a refcount of 2. It leaks if returned from
open_cached_dir().
Fix this by setting cfid->has_lease when the ref is actually taken; the
cfid will not be used by other threads until it has a valid time.
Addresses these kmemleaks:
unreferenced object 0xffff8881090c4000 (size 1024):
comm "bash", pid 1860, jiffies 4295126592
hex dump (first 32 bytes):
00 01 00 00 00 00 ad de 22 01 00 00 00 00 ad de ........".......
00 ca 45 22 81 88 ff ff f8 dc 4f 04 81 88 ff ff ..E"......O.....
backtrace (crc 6f58c20f):
[<ffffffff8b895a1e>] __kmalloc_cache_noprof+0x2be/0x350
[<ffffffff8bda06e3>] open_cached_dir+0x993/0x1fb0
[<ffffffff8bdaa750>] cifs_readdir+0x15a0/0x1d50
[<ffffffff8b9a853f>] iterate_dir+0x28f/0x4b0
[<ffffffff8b9a9aed>] __x64_sys_getdents64+0xfd/0x200
[<ffffffff8cf6da05>] do_syscall_64+0x95/0x1a0
[<ffffffff8d00012f>] entry_SYSCALL_64_after_hwframe+0x76/0x7e
unreferenced object 0xffff8881044fdcf8 (size 8):
comm "bash", pid 1860, jiffies 4295126592
hex dump (first 8 bytes):
00 cc cc cc cc cc cc cc ........
backtrace (crc 10c106a9):
[<ffffffff8b89a3d3>] __kmalloc_node_track_caller_noprof+0x363/0x480
[<ffffffff8b7d7256>] kstrdup+0x36/0x60
[<ffffffff8bda0700>] open_cached_dir+0x9b0/0x1fb0
[<ffffffff8bdaa750>] cifs_readdir+0x15a0/0x1d50
[<ffffffff8b9a853f>] iterate_dir+0x28f/0x4b0
[<ffffffff8b9a9aed>] __x64_sys_getdents64+0xfd/0x200
[<ffffffff8cf6da05>] do_syscall_64+0x95/0x1a0
[<ffffffff8d00012f>] entry_SYSCALL_64_after_hwframe+0x76/0x7e
And addresses these BUG splats when unmounting the SMB filesystem:
BUG: Dentry ffff888140590ba0{i=1000000000080,n=/} still in use (2) [unmount of cifs cifs]
WARNING: CPU: 3 PID: 3433 at fs/dcache.c:1536 umount_check+0xd0/0x100
Modules linked in:
CPU: 3 UID: 0 PID: 3433 Comm: bash Not tainted 6.12.0-rc4-g850925a8133c-dirty #49
Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 11/12/2020
RIP: 0010:umount_check+0xd0/0x100
Code: 8d 7c 24 40 e8 31 5a f4 ff 49 8b 54 24 40 41 56 49 89 e9 45 89 e8 48 89 d9 41 57 48 89 de 48 c7 c7 80 e7 db ac e8 f0 72 9a ff <0f> 0b 58 31 c0 5a 5b 5d 41 5c 41 5d 41 5e 41 5f e9 2b e5 5d 01 41
RSP: 0018:ffff88811cc27978 EFLAGS: 00010286
RAX: 0000000000000000 RBX: ffff888140590ba0 RCX: ffffffffaaf20bae
RDX: dffffc0000000000 RSI: 0000000000000008 RDI: ffff8881f6fb6f40
RBP: ffff8881462ec000 R08: 0000000000000001 R09: ffffed1023984ee3
R10: ffff88811cc2771f R11: 00000000016cfcc0 R12: ffff888134383e08
R13: 0000000000000002 R14: ffff8881462ec668 R15: ffffffffaceab4c0
FS: 00007f23bfa98740(0000) GS:ffff8881f6f80000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000556de4a6f808 CR3: 0000000123c80000 CR4: 0000000000350ef0
Call Trace:
<TASK>
d_walk+0x6a/0x530
shrink_dcache_for_umount+0x6a/0x200
generic_shutdown_super+0x52/0x2a0
kill_anon_super+0x22/0x40
cifs_kill_sb+0x159/0x1e0
deactivate_locked_super+0x66/0xe0
cleanup_mnt+0x140/0x210
task_work_run+0xfb/0x170
syscall_exit_to_user_mode+0x29f/0x2b0
do_syscall_64+0xa1/0x1a0
entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7f23bfb93ae7
Code: ff ff ff ff c3 66 0f 1f 44 00 00 48 8b 0d 11 93 0d 00 f7 d8 64 89 01 b8 ff ff ff ff eb bf 0f 1f 44 00 00 b8 50 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d e9 92 0d 00 f7 d8 64 89
---truncated---