| 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-2024-40979: wifi: ath12k: fix kernel crash during resume |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| wifi: ath12k: fix kernel crash during resume |
| |
| Currently during resume, QMI target memory is not properly handled, resulting |
| in kernel crash in case DMA remap is not supported: |
| |
| BUG: Bad page state in process kworker/u16:54 pfn:36e80 |
| page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x36e80 |
| page dumped because: nonzero _refcount |
| Call Trace: |
| bad_page |
| free_page_is_bad_report |
| __free_pages_ok |
| __free_pages |
| dma_direct_free |
| dma_free_attrs |
| ath12k_qmi_free_target_mem_chunk |
| ath12k_qmi_msg_mem_request_cb |
| |
| The reason is: |
| Once ath12k module is loaded, firmware sends memory request to host. In case |
| DMA remap not supported, ath12k refuses the first request due to failure in |
| allocating with large segment size: |
| |
| ath12k_pci 0000:04:00.0: qmi firmware request memory request |
| ath12k_pci 0000:04:00.0: qmi mem seg type 1 size 7077888 |
| ath12k_pci 0000:04:00.0: qmi mem seg type 4 size 8454144 |
| ath12k_pci 0000:04:00.0: qmi dma allocation failed (7077888 B type 1), will try later with small size |
| ath12k_pci 0000:04:00.0: qmi delays mem_request 2 |
| ath12k_pci 0000:04:00.0: qmi firmware request memory request |
| |
| Later firmware comes back with more but small segments and allocation |
| succeeds: |
| |
| ath12k_pci 0000:04:00.0: qmi mem seg type 1 size 524288 |
| ath12k_pci 0000:04:00.0: qmi mem seg type 1 size 524288 |
| ath12k_pci 0000:04:00.0: qmi mem seg type 1 size 524288 |
| ath12k_pci 0000:04:00.0: qmi mem seg type 1 size 524288 |
| ath12k_pci 0000:04:00.0: qmi mem seg type 1 size 524288 |
| ath12k_pci 0000:04:00.0: qmi mem seg type 1 size 524288 |
| ath12k_pci 0000:04:00.0: qmi mem seg type 1 size 524288 |
| ath12k_pci 0000:04:00.0: qmi mem seg type 1 size 262144 |
| ath12k_pci 0000:04:00.0: qmi mem seg type 1 size 524288 |
| ath12k_pci 0000:04:00.0: qmi mem seg type 1 size 524288 |
| ath12k_pci 0000:04:00.0: qmi mem seg type 1 size 524288 |
| ath12k_pci 0000:04:00.0: qmi mem seg type 1 size 524288 |
| ath12k_pci 0000:04:00.0: qmi mem seg type 1 size 524288 |
| ath12k_pci 0000:04:00.0: qmi mem seg type 4 size 524288 |
| ath12k_pci 0000:04:00.0: qmi mem seg type 4 size 524288 |
| ath12k_pci 0000:04:00.0: qmi mem seg type 4 size 524288 |
| ath12k_pci 0000:04:00.0: qmi mem seg type 4 size 524288 |
| ath12k_pci 0000:04:00.0: qmi mem seg type 4 size 524288 |
| ath12k_pci 0000:04:00.0: qmi mem seg type 4 size 524288 |
| ath12k_pci 0000:04:00.0: qmi mem seg type 4 size 524288 |
| ath12k_pci 0000:04:00.0: qmi mem seg type 4 size 524288 |
| ath12k_pci 0000:04:00.0: qmi mem seg type 4 size 524288 |
| ath12k_pci 0000:04:00.0: qmi mem seg type 4 size 524288 |
| ath12k_pci 0000:04:00.0: qmi mem seg type 4 size 524288 |
| ath12k_pci 0000:04:00.0: qmi mem seg type 4 size 524288 |
| ath12k_pci 0000:04:00.0: qmi mem seg type 4 size 524288 |
| ath12k_pci 0000:04:00.0: qmi mem seg type 4 size 524288 |
| ath12k_pci 0000:04:00.0: qmi mem seg type 4 size 524288 |
| ath12k_pci 0000:04:00.0: qmi mem seg type 4 size 524288 |
| ath12k_pci 0000:04:00.0: qmi mem seg type 4 size 65536 |
| ath12k_pci 0000:04:00.0: qmi mem seg type 1 size 524288 |
| |
| Now ath12k is working. If suspend is triggered, firmware will be reloaded |
| during resume. As same as before, firmware requests two large segments at |
| first. In ath12k_qmi_msg_mem_request_cb() segment count and size are |
| assigned: |
| |
| ab->qmi.mem_seg_count == 2 |
| ab->qmi.target_mem[0].size == 7077888 |
| ab->qmi.target_mem[1].size == 8454144 |
| |
| Then allocation failed like before and ath12k_qmi_free_target_mem_chunk() |
| is called to free all allocated segments. Note the first segment is skipped |
| because its v.addr is cleared due to allocation failure: |
| |
| chunk->v.addr = dma_alloc_coherent() |
| |
| Also note that this leaks that segment because it has not been freed. |
| |
| While freeing the second segment, a size of 8454144 is passed to |
| dma_free_coherent(). However remember that this segment is allocated at |
| the first time firmware is loaded, before suspend. So its real size is |
| 524288, much smaller than 8454144. As a result kernel found we are freeing |
| some memory which is in use and thus crashed. |
| |
| So one possible fix would be to free those segments during suspend. This |
| works because with them freed, ath12k_qmi_free_target_mem_chunk() does |
| nothing: all segment addresses are NULL so dma_free_coherent() is not called. |
| |
| But note that ath11k has similar logic but never hits this issue. Reviewing |
| code there shows the luck comes from QMI memory reuse logic. So the decision |
| is to port it to ath12k. Like in ath11k, the crash is avoided by adding |
| prev_size to target_mem_chunk structure and caching real segment size in it, |
| then prev_size instead of current size is passed to dma_free_coherent(), |
| no unexpected memory is freed now. |
| |
| Also reuse m3 buffer. |
| |
| Tested-on: WCN7850 hw2.0 PCI WLAN.HMT.1.0-03427-QCAHMTSWPL_V1.0_V2.0_SILICONZ-1.15378.4 |
| Tested-on: WCN7850 hw2.0 PCI WLAN.HMT.1.0.c5-00481-QCAHMTSWPL_V1.0_V2.0_SILICONZ-3 |
| |
| The Linux kernel CVE team has assigned CVE-2024-40979 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 6.3 with commit d889913205cf7ebda905b1e62c5867ed4e39f6c2 and fixed in 6.9.7 with commit bb50a4e711ff95348ad53641acb1306d89eb4c3a |
| Issue introduced in 6.3 with commit d889913205cf7ebda905b1e62c5867ed4e39f6c2 and fixed in 6.10 with commit 303c017821d88ebad887814114d4e5966d320b28 |
| |
| 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-2024-40979 |
| 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/net/wireless/ath/ath12k/core.c |
| drivers/net/wireless/ath/ath12k/qmi.c |
| drivers/net/wireless/ath/ath12k/qmi.h |
| |
| |
| 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/bb50a4e711ff95348ad53641acb1306d89eb4c3a |
| https://git.kernel.org/stable/c/303c017821d88ebad887814114d4e5966d320b28 |
