5.5 MEDIUM
- CVSS version (CVSS): 3.1
- Attack Vector (AV): Local (L)
- Attack Complexity (AC): Low (L)
- Privileges Required (PR): Low (L)
- User Interaction (UI): None (N)
- Scope (S): Unchanged (U)
- Confidentiality (C): None (N)
- Integrity (I): None (N)
- Availability (A): High (H)
- Modified Attack Vector (MAV): Local (L)
- Modified Attack Complexity (MAC): Low (L)
- Modified Privileges Required (MPR): Low (L)
- Modified User Interaction (MUI): None (N)
- Modified Confidentiality (MC): None (N)
- Modified Scope (MS): Unchanged (U)
- Modified Integrity (MI): None (N)
- Modified Availability (MA): High (H)
Activity log
- Created suggestion
User-triggerable kernel NULL-pointer dereference (DoS) in `k_thread_name_copy()` syscall verifier
The CONFIG_USERSPACE verification handler for the k_thread_name_copy() system call (z_vrfy_k_thread_name_copy() in kernel/thread.c) calls k_object_find() on the caller-supplied thread pointer and then dereferences the returned struct k_object without checking it for NULL. k_object_find() returns NULL whenever the supplied pointer is not a registered (static or dynamic) kernel object. The pre-fix guard tested thread == NULL instead of ko == NULL, so an unprivileged user-mode thread that invokes k_thread_name_copy() with any non-NULL but unregistered pointer (e.g. an arbitrary address) passes the NULL test, after which the verifier reads ko->type through a NULL pointer. Because the syscall verifier runs in supervisor mode, this NULL dereference is a kernel-mode fault that halts or reboots the system, allowing untrusted user code to crash the kernel across the userspace security boundary (denial of service). The marshaller passes the thread argument to the verifier without any prior K_SYSCALL_OBJ validation, so the bad pointer reaches the defect directly. The flaw affects builds with CONFIG_USERSPACE and CONFIG_THREAD_NAME enabled and has been present since the special-case lookup was introduced around v2.0.0; it is present in v4.4.0 and earlier. The fix changes the guard to check the k_object_find() return value (ko == NULL) before dereferencing it.
References
Affected products
- <4.5.0
Matching in nixpkgs
pkgs.python313Packages.smoke-zephyr
Python utility collection
pkgs.python314Packages.smoke-zephyr
Python utility collection
pkgs.python313Packages.zephyr-python-api
Set of wrappers for Zephyr Scale (TM4J) REST API
pkgs.python314Packages.zephyr-python-api
Set of wrappers for Zephyr Scale (TM4J) REST API
pkgs.python313Packages.zephyr-test-management
Wrappers for both Zephyr Scale and Zephyr Squad (TM4J) REST APIs
Package maintainers
-
@fabaff Fabian Affolter <mail@fabian-affolter.ch>
-
@Steinhagen Viorel-Cătălin Răpițeanu <rapiteanu.catalin@gmail.com>