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

First published: Fri Dec 27 2024(Updated: )

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+0x2c4/0x700 vfs_open+0x2c/0x3c path_openat+0xa64/0xc60 do_filp_open+0xb8/0x164 do_sys_openat2+0x84/0xf0 __arm64_sys_openat+0x70/0x9c invoke_syscall+0x58/0x114 el0_svc_common+0x80/0xe0 do_el0_svc+0x1c/0x28 el0_svc+0x38/0x68

Credit: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

Never miss a vulnerability like this again

Sign up to SecAlerts for real-time vulnerability data matched to your software, aggregated from hundreds of sources.

Read MoreStart Free Trial

• agent/references
• agent/title
• agent/type
• agent/description
• agent/first-publish-date
• agent/author
• agent/event
• agent/severity
• agent/weakness
• agent/remedy
• agent/softwarecombine
• agent/source
• agent/tags
• collector/mitre-cve
• source/MITRE
• agent/last-modified-date
• collector/nvd-api
• source/NVD
• agent/software-canonical-lookup
• agent/software-canonical-lookup-request
• vendor/linux
• canonical/linux kernel
• version/linux kernel/2.6.27
• version/linux kernel/5.5
• version/linux kernel/5.11
• version/linux kernel/5.16
• version/linux kernel/6.2
• version/linux kernel/6.7
• version/linux kernel/6.13-rc1
• version/linux kernel/6.13-rc2