From bippy-851b3ed3d212 Mon Sep 17 00:00:00 2001 From: Greg Kroah-Hartman To: Reply-to: , Subject: CVE-2021-46920: dmaengine: idxd: Fix clobbering of SWERR overflow bit on writeback Description =========== In the Linux kernel, the following vulnerability has been resolved: dmaengine: idxd: Fix clobbering of SWERR overflow bit on writeback Current code blindly writes over the SWERR and the OVERFLOW bits. Write back the bits actually read instead so the driver avoids clobbering the OVERFLOW bit that comes after the register is read. The Linux kernel CVE team has assigned CVE-2021-46920 to this issue. Affected and fixed versions =========================== Issue introduced in 5.6 with commit bfe1d56091c1 and fixed in 5.10.32 with commit a5ad12d5d69c Issue introduced in 5.6 with commit bfe1d56091c1 and fixed in 5.11.16 with commit 02981a44a0e4 Issue introduced in 5.6 with commit bfe1d56091c1 and fixed in 5.12 with commit ea941ac294d7 Please see https://www.kernel.org for a full list of currently supported kernel versions by the kernel community. Unaffected versions might change over time as fixes are backported to older supported kernel versions. The official CVE entry at https://cve.org/CVERecord/?id=CVE-2021-46920 will be updated if fixes are backported, please check that for the most up to date information about this issue. Affected files ============== The file(s) affected by this issue are: drivers/dma/idxd/irq.c Mitigation ========== The Linux kernel CVE team recommends that you update to the latest stable kernel version for this, and many other bugfixes. Individual changes are never tested alone, but rather are part of a larger kernel release. Cherry-picking individual commits is not recommended or supported by the Linux kernel community at all. If however, updating to the latest release is impossible, the individual changes to resolve this issue can be found at these commits: https://git.kernel.org/stable/c/a5ad12d5d69c63af289a37f05187a0c6fe93553d https://git.kernel.org/stable/c/02981a44a0e402089775416371bd2e0c935685f8 https://git.kernel.org/stable/c/ea941ac294d75d0ace50797aebf0056f6f8f7a7f