CVE-2025-38690

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

drm/xe/migrate: prevent infinite recursion

If the buf + offset is not aligned to XE_CAHELINE_BYTES we fallback to using a bounce buffer. However the bounce buffer here is allocated on the stack, and the only alignment requirement here is that its naturally aligned to u8, and not XE_CACHELINE_BYTES. If the bounce buffer is also misaligned we then recurse back into the function again, however the new bounce buffer might also not be aligned, and might never be until we eventually blow through the stack, as we keep recursing.

Instead of using the stack use kmalloc, which should respect the power-of-two alignment request here. Fixes a kernel panic when triggering this path through eudebug.

v2 (Stuart):

• Add build bug check for power-of-two restriction
• s/EINVAL/ENOMEM/

(cherry picked from commit 38b34e928a08ba594c4bbf7118aa3aadacd62fff)

Weakness

The product contains an assert() or similar statement that can be triggered by an attacker, which leads to an application exit or other behavior that is more severe than necessary.

Affected Software

Extended Description

While assertion is good for catching logic errors and reducing the chances of reaching more serious vulnerability conditions, it can still lead to a denial of service. For example, if a server handles multiple simultaneous connections, and an assert() occurs in one single connection that causes all other connections to be dropped, this is a reachable assertion that leads to a denial of service.

Potential Mitigations

References

• https://git.kernel.org/stable/c/89f511c024879c5812cc0c010a6663b5e49950f3
• https://git.kernel.org/stable/c/9d7a1cbebbb691891671def57407ba2f8ee914e8