| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| In the Linux kernel, the following vulnerability has been resolved:
linkwatch: use __dev_put() in callers to prevent UAF
After linkwatch_do_dev() calls __dev_put() to release the linkwatch
reference, the device refcount may drop to 1. At this point,
netdev_run_todo() can proceed (since linkwatch_sync_dev() sees an
empty list and returns without blocking), wait for the refcount to
become 1 via netdev_wait_allrefs_any(), and then free the device
via kobject_put().
This creates a use-after-free when __linkwatch_run_queue() tries to
call netdev_unlock_ops() on the already-freed device.
Note that adding netdev_lock_ops()/netdev_unlock_ops() pair in
netdev_run_todo() before kobject_put() would not work, because
netdev_lock_ops() is conditional - it only locks when
netdev_need_ops_lock() returns true. If the device doesn't require
ops_lock, linkwatch won't hold any lock, and netdev_run_todo()
acquiring the lock won't provide synchronization.
Fix this by moving __dev_put() from linkwatch_do_dev() to its
callers. The device reference logically pairs with de-listing the
device, so it's reasonable for the caller that did the de-listing
to release it. This allows placing __dev_put() after all device
accesses are complete, preventing UAF.
The bug can be reproduced by adding mdelay(2000) after
linkwatch_do_dev() in __linkwatch_run_queue(), then running:
ip tuntap add mode tun name tun_test
ip link set tun_test up
ip link set tun_test carrier off
ip link set tun_test carrier on
sleep 0.5
ip tuntap del mode tun name tun_test
KASAN report:
==================================================================
BUG: KASAN: use-after-free in netdev_need_ops_lock include/net/netdev_lock.h:33 [inline]
BUG: KASAN: use-after-free in netdev_unlock_ops include/net/netdev_lock.h:47 [inline]
BUG: KASAN: use-after-free in __linkwatch_run_queue+0x865/0x8a0 net/core/link_watch.c:245
Read of size 8 at addr ffff88804de5c008 by task kworker/u32:10/8123
CPU: 0 UID: 0 PID: 8123 Comm: kworker/u32:10 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Workqueue: events_unbound linkwatch_event
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:378 [inline]
print_report+0x156/0x4c9 mm/kasan/report.c:482
kasan_report+0xdf/0x1a0 mm/kasan/report.c:595
netdev_need_ops_lock include/net/netdev_lock.h:33 [inline]
netdev_unlock_ops include/net/netdev_lock.h:47 [inline]
__linkwatch_run_queue+0x865/0x8a0 net/core/link_watch.c:245
linkwatch_event+0x8f/0xc0 net/core/link_watch.c:304
process_one_work+0x9c2/0x1840 kernel/workqueue.c:3257
process_scheduled_works kernel/workqueue.c:3340 [inline]
worker_thread+0x5da/0xe40 kernel/workqueue.c:3421
kthread+0x3b3/0x730 kernel/kthread.c:463
ret_from_fork+0x754/0xaf0 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
</TASK>
================================================================== |
| In the Linux kernel, the following vulnerability has been resolved:
cgroup/dmem: avoid pool UAF
An UAF issue was observed:
BUG: KASAN: slab-use-after-free in page_counter_uncharge+0x65/0x150
Write of size 8 at addr ffff888106715440 by task insmod/527
CPU: 4 UID: 0 PID: 527 Comm: insmod 6.19.0-rc7-next-20260129+ #11
Tainted: [O]=OOT_MODULE
Call Trace:
<TASK>
dump_stack_lvl+0x82/0xd0
kasan_report+0xca/0x100
kasan_check_range+0x39/0x1c0
page_counter_uncharge+0x65/0x150
dmem_cgroup_uncharge+0x1f/0x260
Allocated by task 527:
Freed by task 0:
The buggy address belongs to the object at ffff888106715400
which belongs to the cache kmalloc-512 of size 512
The buggy address is located 64 bytes inside of
freed 512-byte region [ffff888106715400, ffff888106715600)
The buggy address belongs to the physical page:
Memory state around the buggy address:
ffff888106715300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff888106715380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888106715400: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff888106715480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888106715500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
The issue occurs because a pool can still be held by a caller after its
associated memory region is unregistered. The current implementation frees
the pool even if users still hold references to it (e.g., before uncharge
operations complete).
This patch adds a reference counter to each pool, ensuring that a pool is
only freed when its reference count drops to zero. |
| The elf_core_dump function in binfmt_elf.c for Linux kernel 2.x.x to 2.2.27-rc2, 2.4.x to 2.4.31-pre1, and 2.6.x to 2.6.12-rc4 allows local users to execute arbitrary code via an ELF binary that, in certain conditions involving the create_elf_tables function, causes a negative length argument to pass a signed integer comparison, leading to a buffer overflow. |
| Race condition in the (1) load_elf_library and (2) binfmt_aout function calls for uselib in Linux kernel 2.4 through 2.429-rc2 and 2.6 through 2.6.10 allows local users to execute arbitrary code by manipulating the VMA descriptor. |
| Integer overflow in sys_epoll_wait in eventpoll.c for Linux kernel 2.6 to 2.6.11 allows local users to overwrite kernel memory via a large number of events. |
| Race condition in Linux kernel 2.6.17.4 and earlier allows local users to gain root privileges by using prctl with PR_SET_DUMPABLE in a way that causes /proc/self/environ to become setuid root. |
| strace allows local users to read arbitrary files via memory mapped file names. |
| The ugidd RPC interface, by design, allows remote attackers to enumerate valid usernames by specifying arbitrary UIDs that ugidd maps to local user and group names. |
| Denial of service in Linux 2.2.x kernels via malformed ICMP packets containing unusual types, codes, and IP header lengths. |
| rpc.mountd on Linux, Ultrix, and possibly other operating systems, allows remote attackers to determine the existence of a file on the server by attempting to mount that file, which generates different error messages depending on whether the file exists or not. |
| mknod in Linux 2.2 follows symbolic links, which could allow local users to overwrite files or gain privileges. |
| The knfsd NFS server in Linux kernel 2.2.x allows remote attackers to cause a denial of service via a negative size value. |
| Linux kernel 2.2.1 through 2.2.19, and 2.4.1 through 2.4.10, allows local users to cause a denial of service via a series of deeply nested symlinks, which causes the kernel to spend extra time when trying to access the link. |
| Multiple TCP implementations could allow remote attackers to cause a denial of service (bandwidth and CPU exhaustion) by setting the maximum segment size (MSS) to a very small number and requesting large amounts of data, which generates more packets with less TCP-level data that amplify network traffic and consume more server CPU to process. |
| Linux kernel, and possibly other operating systems, allows remote attackers to read portions of memory via a series of fragmented ICMP packets that generate an ICMP TTL Exceeded response, which includes portions of the memory in the response packet. |
| The encrypted loop device in Linux kernel 2.4.10 and earlier does not authenticate the entity that is encrypting data, which allows local users to modify encrypted data without knowing the key. |
| The Linux kernel 2.4.20 and earlier, and 2.5.x, when running on x86 systems, allows local users to cause a denial of service (hang) via the emulation mode, which does not properly clear TF and NT EFLAGs. |
| ifconfig, when used on the Linux kernel 2.2 and later, does not report when the network interface is in promiscuous mode if it was put in promiscuous mode using PACKET_MR_PROMISC, which could allow attackers to sniff the network without detection, as demonstrated using libpcap. |
| Linux kernel 2.4.10 through 2.4.21-pre4 does not properly handle the O_DIRECT feature, which allows local attackers with write privileges to read portions of previously deleted files, or cause file system corruption. |
| A race condition in the way env_start and env_end pointers are initialized in the execve system call and used in fs/proc/base.c on Linux 2.4 allows local users to cause a denial of service (crash). |
