Linux Kernel up to 6.9.6 ath12k_qmi_msg_mem_request_cb allocation of resources

Summaryinfo

A vulnerability classified as critical has been found in Linux Kernel up to 6.9.6. Affected by this issue is the function ath12k_qmi_msg_mem_request_cb. Performing a manipulation results in allocation of resources. This vulnerability is known as CVE-2024-40979. No exploit is available. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability classified as critical has been found in Linux Kernel up to 6.9.6. This affects the function ath12k_qmi_msg_mem_request_cb. The manipulation with an unknown input leads to a allocation of resources vulnerability. CWE is classifying the issue as CWE-770. The product allocates a reusable resource or group of resources on behalf of an actor without imposing any restrictions on the size or number of resources that can be allocated, in violation of the intended security policy for that actor. This is going to have an impact on availability. The summary by CVE is:

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 cras ---truncated---

The advisory is shared at git.kernel.org. This vulnerability is uniquely identified as CVE-2024-40979 since 07/12/2024. The exploitability is told to be difficult. Technical details are known, but no exploit is available.

Upgrading to version 6.9.7 eliminates this vulnerability. Applying the patch bb50a4e711ff/303c017821d8 is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

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Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 6.9.0
• 6.9.1
• 6.9.2
• 6.9.3
• 6.9.4
• 6.9.5
• 6.9.6

License

• open-source

Website

• Vendor: https://www.kernel.org/

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Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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