| 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-2024-35809: PCI/PM: Drain runtime-idle callbacks before driver removal |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| PCI/PM: Drain runtime-idle callbacks before driver removal |
| |
| A race condition between the .runtime_idle() callback and the .remove() |
| callback in the rtsx_pcr PCI driver leads to a kernel crash due to an |
| unhandled page fault [1]. |
| |
| The problem is that rtsx_pci_runtime_idle() is not expected to be running |
| after pm_runtime_get_sync() has been called, but the latter doesn't really |
| guarantee that. It only guarantees that the suspend and resume callbacks |
| will not be running when it returns. |
| |
| However, if a .runtime_idle() callback is already running when |
| pm_runtime_get_sync() is called, the latter will notice that the runtime PM |
| status of the device is RPM_ACTIVE and it will return right away without |
| waiting for the former to complete. In fact, it cannot wait for |
| .runtime_idle() to complete because it may be called from that callback (it |
| arguably does not make much sense to do that, but it is not strictly |
| prohibited). |
| |
| Thus in general, whoever is providing a .runtime_idle() callback needs |
| to protect it from running in parallel with whatever code runs after |
| pm_runtime_get_sync(). [Note that .runtime_idle() will not start after |
| pm_runtime_get_sync() has returned, but it may continue running then if it |
| has started earlier.] |
| |
| One way to address that race condition is to call pm_runtime_barrier() |
| after pm_runtime_get_sync() (not before it, because a nonzero value of the |
| runtime PM usage counter is necessary to prevent runtime PM callbacks from |
| being invoked) to wait for the .runtime_idle() callback to complete should |
| it be running at that point. A suitable place for doing that is in |
| pci_device_remove() which calls pm_runtime_get_sync() before removing the |
| driver, so it may as well call pm_runtime_barrier() subsequently, which |
| will prevent the race in question from occurring, not just in the rtsx_pcr |
| driver, but in any PCI drivers providing .runtime_idle() callbacks. |
| |
| The Linux kernel CVE team has assigned CVE-2024-35809 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Fixed in 4.19.312 with commit 9a87375bb586515c0af63d5dcdcd58ec4acf20a6 |
| Fixed in 5.4.274 with commit 47d8aafcfe313511a98f165a54d0adceb34e54b1 |
| Fixed in 5.10.215 with commit bbe068b24409ef740657215605284fc7cdddd491 |
| Fixed in 5.15.154 with commit 7cc94dd36e48879e76ae7a8daea4ff322b7d9674 |
| Fixed in 6.1.84 with commit 900b81caf00c89417172afe0e7e49ac4eb110f4b |
| Fixed in 6.6.24 with commit d86ad8c3e152349454b82f37007ff6ba45f26989 |
| Fixed in 6.7.12 with commit d534198311c345e4b062c4b88bb609efb8bd91d5 |
| Fixed in 6.8.3 with commit 6347348c6aba52dda0b33296684cbb627bdc6970 |
| Fixed in 6.9 with commit 9d5286d4e7f68beab450deddbb6a32edd5ecf4bf |
| |
| 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-2024-35809 |
| 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/pci/pci-driver.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/9a87375bb586515c0af63d5dcdcd58ec4acf20a6 |
| https://git.kernel.org/stable/c/47d8aafcfe313511a98f165a54d0adceb34e54b1 |
| https://git.kernel.org/stable/c/bbe068b24409ef740657215605284fc7cdddd491 |
| https://git.kernel.org/stable/c/7cc94dd36e48879e76ae7a8daea4ff322b7d9674 |
| https://git.kernel.org/stable/c/900b81caf00c89417172afe0e7e49ac4eb110f4b |
| https://git.kernel.org/stable/c/d86ad8c3e152349454b82f37007ff6ba45f26989 |
| https://git.kernel.org/stable/c/d534198311c345e4b062c4b88bb609efb8bd91d5 |
| https://git.kernel.org/stable/c/6347348c6aba52dda0b33296684cbb627bdc6970 |
| https://git.kernel.org/stable/c/9d5286d4e7f68beab450deddbb6a32edd5ecf4bf |
