CVE-2025-21812 — ax25: rcu protect dev->ax25_ptr

Affected: Linux

In the Linux kernel, the following vulnerability has been resolved:

ax25: rcu protect dev->ax25_ptr

syzbot found a lockdep issue [1].

We should remove ax25 RTNL dependency in ax25_setsockopt()

This should also fix a variety of possible UAF in ax25.

[1]

WARNING: possible circular locking dependency detected 6.13.0-rc3-syzkaller-00762-g9268abe611b0 #0 Not tainted ------------------------------------------------------ syz.5.1818/12806 is trying to acquire lock: ffffffff8fcb3988 (rtnl_mutex){+.+.}-{4:4}, at: ax25_setsockopt+0xa55/0xe90 net/ax25/af_ax25.c:680

but task is already holding lock: ffff8880617ac258 (sk_lock-AF_AX25){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1618 [inline] ffff8880617ac258 (sk_lock-AF_AX25){+.+.}-{0:0}, at: ax25_setsockopt+0x209/0xe90 net/ax25/af_ax25.c:574

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #1 (sk_lock-AF_AX25){+.+.}-{0:0}: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849 lock_sock_nested+0x48/0x100 net/core/sock.c:3642 lock_sock include/net/sock.h:1618 [inline] ax25_kill_by_device net/ax25/af_ax25.c:101 [inline] ax25_device_event+0x24d/0x580 net/ax25/af_ax25.c:146 notifier_call_chain+0x1a5/0x3f0 kernel/notifier.c:85 __dev_notify_flags+0x207/0x400 dev_change_flags+0xf0/0x1a0 net/core/dev.c:9026 dev_ifsioc+0x7c8/0xe70 net/core/dev_ioctl.c:563 dev_ioctl+0x719/0x1340 net/core/dev_ioctl.c:820…

USN-7521-1 — linux, linux-azure, linux-azure-6.11, linux-gcp, linux-gcp-6.11, linux-hwe-6.11, linux-oem-6.11, linux-raspi, linux-rea…

Affected: Ubuntu:24.04:LTS: linux-azure-6.11, Ubuntu:24.04:LTS: linux-gcp-6.11, Ubuntu:24.04:LTS: linux-hwe-6.11, Ubuntu:24.04:LTS: linux-oem-6.11

Several security issues were discovered in the Linux kernel. An attacker could possibly use these to compromise the system. This update corrects flaws in the following subsystems: - ARM64 architecture; - PowerPC architecture; - x86 architecture; - Block layer subsystem; - Serial ATA and Parallel ATA drivers; - Drivers core; - Network block device driver; - Bluetooth drivers; - Character device driver; - TPM device driver; - Clock framework and drivers; - Hardware crypto device drivers; - FireWire subsystem; - EFI core; - Qualcomm firmware drivers; - GPIO subsystem; - GPU drivers; - HID subsystem; - I2C subsystem; - I3C subsystem; - InfiniBand drivers; - Input Device (Mouse) drivers; - IOMMU subsystem; - Multiple devices driver; - Media drivers; - NVIDIA Tegra memory controller driver; - Fastrpc Driver; - Network drivers; - Operating Performance Points (OPP) driver; - PCI subsystem; - x86 platform drivers; - PPS (Pulse Per Second) driver; - PTP clock framework; - Remote Processor subsystem; - Real Time Clock drivers; - S/390 drivers; - SCSI subsystem; - QCOM SoC drivers; - SPI subsystem; - Media staging drivers; - Trusted Execution Environment drivers; - TTY drivers; - UFS subsystem; - USB Device Class drivers; - USB core drivers; - USB Gadget drivers; - USB Host Controller drivers; - Framebuffer layer; - File systems infrastructure; - BTRFS file system; - Ceph distributed fi…

Most recent entries from all

CVE-2025-21812 — ax25: rcu protect dev->ax25_ptr

USN-7521-1 — linux, linux-azure, linux-azure-6.11, linux-gcp, linux-gcp-6.11, linux-hwe-6.11, linux-oem-6.11, linux-raspi, linux-rea…