CVE-2024-56670 — usb: gadget: u_serial: Fix the issue that gs_start_io crashed due to accessing null pointer

Affected: Linux

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

usb: gadget: u_serial: Fix the issue that gs_start_io crashed due to accessing null pointer

Considering that in some extreme cases, when u_serial driver is accessed by multiple threads, Thread A is executing the open operation and calling the gs_open, Thread B is executing the disconnect operation and calling the gserial_disconnect function,The port->port_usb pointer will be set to NULL.

E.g. Thread A Thread B gs_open() gadget_unbind_driver() gs_start_io() composite_disconnect() gs_start_rx() gserial_disconnect() ... ... spin_unlock(&port->port_lock) status = usb_ep_queue() spin_lock(&port->port_lock) spin_lock(&port->port_lock) port->port_usb = NULL gs_free_requests(port->port_usb->in) spin_unlock(&port->port_lock) Crash

This causes thread A to access a null pointer (port->port_usb is null) when calling the gs_free_requests function, causing a crash.

If port_usb is NULL, the release request will be skipped as it will be done by gserial_disconnect.

So add a null pointer check to gs_start_io before attempting to access the value of the pointer port->port_usb.

Call trace: gs_start_io+0x164/0x25c gs_open+0x108/0x13c tty_open+0x314/0x638 chrdev_open+0x1b8/0x258 do_dentry_open+…

USN-7379-1 — linux, linux-aws, linux-azure, linux-gcp, linux-hwe-6.11, linux-oracle, linux-realtime vulnerabilities

Affected: Ubuntu:24.04:LTS: linux-hwe-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; - MIPS architecture; - PowerPC architecture; - RISC-V architecture; - S390 architecture; - x86 architecture; - Block layer subsystem; - Compute Acceleration Framework; - ACPI drivers; - Drivers core; - Ublk userspace block driver; - Virtio block driver; - Bluetooth drivers; - Buffer Sharing and Synchronization framework; - DMA engine subsystem; - EFI core; - GPIO subsystem; - GPU drivers; - HID subsystem; - Microsoft Hyper-V drivers; - Hardware monitoring drivers; - I3C subsystem; - IIO ADC drivers; - IIO subsystem; - InfiniBand drivers; - IOMMU subsystem; - LED subsystem; - Multiple devices driver; - Media drivers; - Microchip PCI driver; - MTD block device drivers; - Network drivers; - Mellanox network drivers; - STMicroelectronics network drivers; - NVME drivers; - PCI subsystem; - PHY drivers; - Pin controllers subsystem; - x86 platform drivers; - i.MX PM domains; - Power supply drivers; - Voltage and Current Regulator drivers; - SCSI subsystem; - i.MX SoC drivers; - SPI subsystem; - UFS subsystem; - USB Gadget drivers; - TDX Guest driver; - AFS file system; - BTRFS file system; - Ceph distributed file system; - File systems infrastructure; - F2FS file system; - JFFS…

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CVE-2024-56670 — usb: gadget: u_serial: Fix the issue that gs_start_io crashed due to accessing null pointer

USN-7379-1 — linux, linux-aws, linux-azure, linux-gcp, linux-hwe-6.11, linux-oracle, linux-realtime vulnerabilities