Security Vulnerabilities
- CVEs Published In June 2024
In the Linux kernel, the following vulnerability has been resolved:
eth: sungem: remove .ndo_poll_controller to avoid deadlocks
Erhard reports netpoll warnings from sungem:
netpoll_send_skb_on_dev(): eth0 enabled interrupts in poll (gem_start_xmit+0x0/0x398)
WARNING: CPU: 1 PID: 1 at net/core/netpoll.c:370 netpoll_send_skb+0x1fc/0x20c
gem_poll_controller() disables interrupts, which may sleep.
We can't sleep in netpoll, it has interrupts disabled completely.
Strangely, gem_poll_controller() doesn't even poll the completions,
and instead acts as if an interrupt has fired so it just schedules
NAPI and exits. None of this has been necessary for years, since
netpoll invokes NAPI directly.
In the Linux kernel, the following vulnerability has been resolved:
md: fix resync softlockup when bitmap size is less than array size
Is is reported that for dm-raid10, lvextend + lvchange --syncaction will
trigger following softlockup:
kernel:watchdog: BUG: soft lockup - CPU#3 stuck for 26s! [mdX_resync:6976]
CPU: 7 PID: 3588 Comm: mdX_resync Kdump: loaded Not tainted 6.9.0-rc4-next-20240419 #1
RIP: 0010:_raw_spin_unlock_irq+0x13/0x30
Call Trace:
<TASK>
md_bitmap_start_sync+0x6b/0xf0
raid10_sync_request+0x25c/0x1b40 [raid10]
md_do_sync+0x64b/0x1020
md_thread+0xa7/0x170
kthread+0xcf/0x100
ret_from_fork+0x30/0x50
ret_from_fork_asm+0x1a/0x30
And the detailed process is as follows:
md_do_sync
j = mddev->resync_min
while (j < max_sectors)
sectors = raid10_sync_request(mddev, j, &skipped)
if (!md_bitmap_start_sync(..., &sync_blocks))
// md_bitmap_start_sync set sync_blocks to 0
return sync_blocks + sectors_skippe;
// sectors = 0;
j += sectors;
// j never change
Root cause is that commit 301867b1c168 ("md/raid10: check
slab-out-of-bounds in md_bitmap_get_counter") return early from
md_bitmap_get_counter(), without setting returned blocks.
Fix this problem by always set returned blocks from
md_bitmap_get_counter"(), as it used to be.
Noted that this patch just fix the softlockup problem in kernel, the
case that bitmap size doesn't match array size still need to be fixed.
In the Linux kernel, the following vulnerability has been resolved:
jffs2: prevent xattr node from overflowing the eraseblock
Add a check to make sure that the requested xattr node size is no larger
than the eraseblock minus the cleanmarker.
Unlike the usual inode nodes, the xattr nodes aren't split into parts
and spread across multiple eraseblocks, which means that a xattr node
must not occupy more than one eraseblock. If the requested xattr value is
too large, the xattr node can spill onto the next eraseblock, overwriting
the nodes and causing errors such as:
jffs2: argh. node added in wrong place at 0x0000b050(2)
jffs2: nextblock 0x0000a000, expected at 0000b00c
jffs2: error: (823) do_verify_xattr_datum: node CRC failed at 0x01e050,
read=0xfc892c93, calc=0x000000
jffs2: notice: (823) jffs2_get_inode_nodes: Node header CRC failed
at 0x01e00c. {848f,2fc4,0fef511f,59a3d171}
jffs2: Node at 0x0000000c with length 0x00001044 would run over the
end of the erase block
jffs2: Perhaps the file system was created with the wrong erase size?
jffs2: jffs2_scan_eraseblock(): Magic bitmask 0x1985 not found
at 0x00000010: 0x1044 instead
This breaks the filesystem and can lead to KASAN crashes such as:
BUG: KASAN: slab-out-of-bounds in jffs2_sum_add_kvec+0x125e/0x15d0
Read of size 4 at addr ffff88802c31e914 by task repro/830
CPU: 0 PID: 830 Comm: repro Not tainted 6.9.0-rc3+ #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
BIOS Arch Linux 1.16.3-1-1 04/01/2014
Call Trace:
<TASK>
dump_stack_lvl+0xc6/0x120
print_report+0xc4/0x620
? __virt_addr_valid+0x308/0x5b0
kasan_report+0xc1/0xf0
? jffs2_sum_add_kvec+0x125e/0x15d0
? jffs2_sum_add_kvec+0x125e/0x15d0
jffs2_sum_add_kvec+0x125e/0x15d0
jffs2_flash_direct_writev+0xa8/0xd0
jffs2_flash_writev+0x9c9/0xef0
? __x64_sys_setxattr+0xc4/0x160
? do_syscall_64+0x69/0x140
? entry_SYSCALL_64_after_hwframe+0x76/0x7e
[...]
Found by Linux Verification Center (linuxtesting.org) with Syzkaller.
In the Linux kernel, the following vulnerability has been resolved:
ALSA: Fix deadlocks with kctl removals at disconnection
In snd_card_disconnect(), we set card->shutdown flag at the beginning,
call callbacks and do sync for card->power_ref_sleep waiters at the
end. The callback may delete a kctl element, and this can lead to a
deadlock when the device was in the suspended state. Namely:
* A process waits for the power up at snd_power_ref_and_wait() in
snd_ctl_info() or read/write() inside card->controls_rwsem.
* The system gets disconnected meanwhile, and the driver tries to
delete a kctl via snd_ctl_remove*(); it tries to take
card->controls_rwsem again, but this is already locked by the
above. Since the sleeper isn't woken up, this deadlocks.
An easy fix is to wake up sleepers before processing the driver
disconnect callbacks but right after setting the card->shutdown flag.
Then all sleepers will abort immediately, and the code flows again.
So, basically this patch moves the wait_event() call at the right
timing. While we're at it, just to be sure, call wait_event_all()
instead of wait_event(), although we don't use exclusive events on
this queue for now.
In the Linux kernel, the following vulnerability has been resolved:
epoll: be better about file lifetimes
epoll can call out to vfs_poll() with a file pointer that may race with
the last 'fput()'. That would make f_count go down to zero, and while
the ep->mtx locking means that the resulting file pointer tear-down will
be blocked until the poll returns, it means that f_count is already
dead, and any use of it won't actually get a reference to the file any
more: it's dead regardless.
Make sure we have a valid ref on the file pointer before we call down to
vfs_poll() from the epoll routines.
In the Linux kernel, the following vulnerability has been resolved:
drm/amdgpu/mes: fix use-after-free issue
Delete fence fallback timer to fix the ramdom
use-after-free issue.
v2: move to amdgpu_mes.c
In the Linux kernel, the following vulnerability has been resolved:
nilfs2: fix potential hang in nilfs_detach_log_writer()
Syzbot has reported a potential hang in nilfs_detach_log_writer() called
during nilfs2 unmount.
Analysis revealed that this is because nilfs_segctor_sync(), which
synchronizes with the log writer thread, can be called after
nilfs_segctor_destroy() terminates that thread, as shown in the call trace
below:
nilfs_detach_log_writer
nilfs_segctor_destroy
nilfs_segctor_kill_thread --> Shut down log writer thread
flush_work
nilfs_iput_work_func
nilfs_dispose_list
iput
nilfs_evict_inode
nilfs_transaction_commit
nilfs_construct_segment (if inode needs sync)
nilfs_segctor_sync --> Attempt to synchronize with
log writer thread
*** DEADLOCK ***
Fix this issue by changing nilfs_segctor_sync() so that the log writer
thread returns normally without synchronizing after it terminates, and by
forcing tasks that are already waiting to complete once after the thread
terminates.
The skipped inode metadata flushout will then be processed together in the
subsequent cleanup work in nilfs_segctor_destroy().
In the Linux kernel, the following vulnerability has been resolved:
nilfs2: fix use-after-free of timer for log writer thread
Patch series "nilfs2: fix log writer related issues".
This bug fix series covers three nilfs2 log writer-related issues,
including a timer use-after-free issue and potential deadlock issue on
unmount, and a potential freeze issue in event synchronization found
during their analysis. Details are described in each commit log.
This patch (of 3):
A use-after-free issue has been reported regarding the timer sc_timer on
the nilfs_sc_info structure.
The problem is that even though it is used to wake up a sleeping log
writer thread, sc_timer is not shut down until the nilfs_sc_info structure
is about to be freed, and is used regardless of the thread's lifetime.
Fix this issue by limiting the use of sc_timer only while the log writer
thread is alive.
In the Linux kernel, the following vulnerability has been resolved:
net: ti: icssg_prueth: Fix NULL pointer dereference in prueth_probe()
In the prueth_probe() function, if one of the calls to emac_phy_connect()
fails due to of_phy_connect() returning NULL, then the subsequent call to
phy_attached_info() will dereference a NULL pointer.
Check the return code of emac_phy_connect and fail cleanly if there is an
error.
In the Linux kernel, the following vulnerability has been resolved:
tools/nolibc/stdlib: fix memory error in realloc()
Pass user_p_len to memcpy() instead of heap->len to prevent realloc()
from copying an extra sizeof(heap) bytes from beyond the allocated
region.