| From bippy-5f407fcff5a0 Mon Sep 17 00:00:00 2001 |
| From: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| To: <linux-cve-announce@vger.kernel.org> |
| Reply-to: <cve@kernel.org>, <linux-kernel@vger.kernel.org> |
| Subject: CVE-2024-26761: cxl/pci: Fix disabling memory if DVSEC CXL Range does not match a CFMWS window |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| cxl/pci: Fix disabling memory if DVSEC CXL Range does not match a CFMWS window |
| |
| The Linux CXL subsystem is built on the assumption that HPA == SPA. |
| That is, the host physical address (HPA) the HDM decoder registers are |
| programmed with are system physical addresses (SPA). |
| |
| During HDM decoder setup, the DVSEC CXL range registers (cxl-3.1, |
| 8.1.3.8) are checked if the memory is enabled and the CXL range is in |
| a HPA window that is described in a CFMWS structure of the CXL host |
| bridge (cxl-3.1, 9.18.1.3). |
| |
| Now, if the HPA is not an SPA, the CXL range does not match a CFMWS |
| window and the CXL memory range will be disabled then. The HDM decoder |
| stops working which causes system memory being disabled and further a |
| system hang during HDM decoder initialization, typically when a CXL |
| enabled kernel boots. |
| |
| Prevent a system hang and do not disable the HDM decoder if the |
| decoder's CXL range is not found in a CFMWS window. |
| |
| Note the change only fixes a hardware hang, but does not implement |
| HPA/SPA translation. Support for this can be added in a follow on |
| patch series. |
| |
| The Linux kernel CVE team has assigned CVE-2024-26761 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 5.19 with commit 34e37b4c432cd0f1842b352fde4b8878b4166888 and fixed in 6.1.80 with commit 031217128990d7f0ab8c46db1afb3cf1e075fd29 |
| Issue introduced in 5.19 with commit 34e37b4c432cd0f1842b352fde4b8878b4166888 and fixed in 6.6.19 with commit 2cc1a530ab31c65b52daf3cb5d0883c8b614ea69 |
| Issue introduced in 5.19 with commit 34e37b4c432cd0f1842b352fde4b8878b4166888 and fixed in 6.7.7 with commit 3a3181a71935774bda2398451256d7441426420b |
| Issue introduced in 5.19 with commit 34e37b4c432cd0f1842b352fde4b8878b4166888 and fixed in 6.8 with commit 0cab687205986491302cd2e440ef1d253031c221 |
| |
| 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-2024-26761 |
| 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/cxl/core/pci.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/031217128990d7f0ab8c46db1afb3cf1e075fd29 |
| https://git.kernel.org/stable/c/2cc1a530ab31c65b52daf3cb5d0883c8b614ea69 |
| https://git.kernel.org/stable/c/3a3181a71935774bda2398451256d7441426420b |
| https://git.kernel.org/stable/c/0cab687205986491302cd2e440ef1d253031c221 |
