wifi: ath12k: backport CVE-2024-40979 fixes

Hi Greg, Sasha, and wifi ath12k maintainers,

These patches are a backport for CVE-2024-40979 on 6.6.y. The second patch depends on the first, so I kept the upstream ordering instead of folding either change into the other.

Both patches are already present in 6.12.y, 6.18.y, and 7.2.y. Could you please queue this series for 6.6.y?

AI assistance: An LLM helped identify, adapt, and validate these backports; I reviewed the resulting code and validation evidence.

Thanks,
Artem

Series:
1. wifi: ath12k: fix kernel crash during resume
2. wifi: ath12k: check M3 buffer size as well whey trying to reuse it

From: Baochen Qiang <[email protected]>

[ Upstream commit 303c017821d88ebad887814114d4e5966d320b28 ]

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

[ Backport to 6.6.y: carried target-memory reuse and prev_size tracking;
the target already retains core resources and reuses M3, whose size check follows in patch 2. ]

---
Hi Greg, Sasha, and wifi ath12k maintainers,

I am working through the small CVE backports still missing from 6.6.y. This one addresses CVE-2024-40979. It tracks the actual target-memory allocation sizes across firmware resume requests.

The fix is already present in 6.12.y, 6.18.y, and 7.2.y, but not in 6.6.y. The target-specific adjustment is recorded in the bracketed note above.

Could you please queue it for 6.6.y?

CVE: CVE-2024-40979
Upstream: 303c017821d88ebad887814114d4e5966d320b28

AI assistance: An LLM helped identify, adapt, and validate this backport; I reviewed the resulting code and validation evidence.

Thanks,
Artem Dinaburg

 drivers/net/wireless/ath/ath12k/qmi.c | 20 +++++++++++++++++++-
 drivers/net/wireless/ath/ath12k/qmi.h |  2 ++
 2 files changed, 21 insertions(+), 1 deletion(-)

index c49f585cc39656..7a9868dbab02d7 100644
@@ -2152,8 +2152,9 @@ static void ath12k_qmi_free_target_mem_chunk(struct ath12k_base *ab)
 	for (i = 0; i < ab->qmi.mem_seg_count; i++) {
 		if (!ab->qmi.target_mem[i].v.addr)
 			continue;
+
 		dma_free_coherent(ab->dev,
-				  ab->qmi.target_mem[i].size,
+				  ab->qmi.target_mem[i].prev_size,
 				  ab->qmi.target_mem[i].v.addr,
 				  ab->qmi.target_mem[i].paddr);
 		ab->qmi.target_mem[i].v.addr = NULL;

@@ -2179,6 +2180,19 @@ static int ath12k_qmi_alloc_target_mem_chunk(struct ath12k_base *ab)
 		case M3_DUMP_REGION_TYPE:
 		case PAGEABLE_MEM_REGION_TYPE:
 		case CALDB_MEM_REGION_TYPE:
+			/* Firmware reloads in recovery/resume. Reuse an
+			 * unchanged allocation rather than allocating it again.
+			 */
+			if (chunk->v.addr) {
+				if (chunk->prev_type == chunk->type &&
+				    chunk->prev_size == chunk->size)
+					goto this_chunk_done;
+
+				dma_free_coherent(ab->dev, chunk->prev_size,
+						  chunk->v.addr, chunk->paddr);
+				chunk->v.addr = NULL;
+			}
+
 			chunk->v.addr = dma_alloc_coherent(ab->dev,
 							   chunk->size,
 							   &chunk->paddr,

@@ -2197,6 +2211,10 @@ static int ath12k_qmi_alloc_target_mem_chunk(struct ath12k_base *ab)
 					    chunk->type, chunk->size);
 				return -ENOMEM;
 			}
+
+			chunk->prev_type = chunk->type;
+			chunk->prev_size = chunk->size;
+this_chunk_done:
 			break;
 		default:
 			ath12k_warn(ab, "memory type %u not supported\n",

index 4c1ba3196a403d..a996c6d57aa7b8 100644
@@ -97,6 +97,8 @@ struct ath12k_qmi_event_msg {
 struct target_mem_chunk {
 	u32 size;
 	u32 type;
+	u32 prev_size;
+	u32 prev_type;
 	dma_addr_t paddr;
 	union {
 		void __iomem *ioaddr;

2.39.5

From: Baochen Qiang <[email protected]>

[ Upstream commit 05090ae82f44570fefddb4e1be1d7e5770d6de40 ]

Currently in recovery/resume cases, we do not free M3 buffer but instead will reuse it. This is done by checking m3_mem->vaddr: if it is not NULL we believe M3 buffer is ready and go ahead to reuse it.

Note that m3_mem->size is not checked. This is safe for now because currently M3 reuse logic only gets executed in recovery/resume cases and the size keeps unchanged in either of them.

However ideally the size should be checked as well, to make the code safer. So add the check there. Now if that check fails, free old M3 buffer and reallocate a new one.

Tested-on: WCN6855 hw2.0 PCI WLAN.HSP.1.1-03125-QCAHSPSWPL_V1_V2_SILICONZ_LITE-3.6510.30

[ Backport to 6.6.y: mapped the M3 size validation onto the target's
older QMI allocation layout. ]

---
Hi Greg, Sasha, and wifi ath12k maintainers,

I am working through the small CVE backports still missing from 6.6.y. This one addresses CVE-2024-40979. It also validates the reusable M3 buffer size and reallocates an undersized buffer.

The fix is already present in 6.12.y, 6.18.y, and 7.2.y, but not in 6.6.y. The target-specific adjustment is recorded in the bracketed note above.

Could you please queue it for 6.6.y?

CVE: CVE-2024-40979
Upstream: 05090ae82f44570fefddb4e1be1d7e5770d6de40

AI assistance: An LLM helped identify, adapt, and validate this backport; I reviewed the resulting code and validation evidence.

Thanks,
Artem Dinaburg

 drivers/net/wireless/ath/ath12k/qmi.c | 39 ++++++++++++++++-----------
 1 file changed, 24 insertions(+), 15 deletions(-)

index 7a9868dbab02d7..48d0043fcee93b 100644
@@ -2511,6 +2511,19 @@ static int ath12k_qmi_load_bdf_qmi(struct ath12k_base *ab,
 	return ret;
 }
 
+static void ath12k_qmi_m3_free(struct ath12k_base *ab)
+{
+	struct m3_mem_region *m3_mem = &ab->qmi.m3_mem;
+
+	if (!m3_mem->vaddr)
+		return;
+
+	dma_free_coherent(ab->dev, m3_mem->size,
+			  m3_mem->vaddr, m3_mem->paddr);
+	m3_mem->vaddr = NULL;
+	m3_mem->size = 0;
+}
+
 static int ath12k_qmi_m3_load(struct ath12k_base *ab)
 {
 	struct m3_mem_region *m3_mem = &ab->qmi.m3_mem;

@@ -2518,9 +2531,6 @@ static int ath12k_qmi_m3_load(struct ath12k_base *ab)
 	char path[100];
 	int ret;
 
-	if (m3_mem->vaddr || m3_mem->size)
-		return 0;
-
 	fw = ath12k_core_firmware_request(ab, ATH12K_M3_FILE);
 	if (IS_ERR(fw)) {
 		ret = PTR_ERR(fw);

@@ -2530,6 +2540,17 @@ static int ath12k_qmi_m3_load(struct ath12k_base *ab)
 		return ret;
 	}
 
+	/* In recovery/resume cases, M3 buffer is not freed, try to reuse that */
+	if (m3_mem->vaddr) {
+		if (m3_mem->size >= fw->size) {
+			release_firmware(fw);
+			return 0;
+		}
+
+		/* Old buffer is too small, free and reallocate */
+		ath12k_qmi_m3_free(ab);
+	}
+
 	m3_mem->vaddr = dma_alloc_coherent(ab->dev,
 					   fw->size, &m3_mem->paddr,
 					   GFP_KERNEL);

@@ -2547,18 +2568,6 @@ static int ath12k_qmi_m3_load(struct ath12k_base *ab)
 	return 0;
 }
 
-static void ath12k_qmi_m3_free(struct ath12k_base *ab)
-{
-	struct m3_mem_region *m3_mem = &ab->qmi.m3_mem;
-
-	if (!m3_mem->vaddr)
-		return;
-
-	dma_free_coherent(ab->dev, m3_mem->size,
-			  m3_mem->vaddr, m3_mem->paddr);
-	m3_mem->vaddr = NULL;
-}
-
 static int ath12k_qmi_wlanfw_m3_info_send(struct ath12k_base *ab)
 {
 	struct m3_mem_region *m3_mem = &ab->qmi.m3_mem;

2.39.5

Queued the pair for 6.6, thanks.

Thanks,
Sasha