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CVE-2025-38072: libnvdimm/labels: Fix divide error in nd_label_data_init()

Description

In the Linux kernel, the following vulnerability has been resolved:

libnvdimm/labels: Fix divide error in nd_label_data_init()

If a faulty CXL memory device returns a broken zero LSA size in its
memory device information (Identify Memory Device (Opcode 4000h), CXL
spec. 3.1, 8.2.9.9.1.1), a divide error occurs in the libnvdimm
driver:

Oops: divide error: 0000 [#1] PREEMPT SMP NOPTI
RIP: 0010:nd_label_data_init+0x10e/0x800 [libnvdimm]

Code and flow:

1) CXL Command 4000h returns LSA size = 0
2) config_size is assigned to zero LSA size (CXL pmem driver):

drivers/cxl/pmem.c: .config_size = mds->lsa_size,

3) max_xfer is set to zero (nvdimm driver):

drivers/nvdimm/label.c: max_xfer = min_t(size_t, ndd->nsarea.max_xfer, config_size);

4) A subsequent DIV_ROUND_UP() causes a division by zero:

drivers/nvdimm/label.c: /* Make our initial read size a multiple of max_xfer size */
drivers/nvdimm/label.c: read_size = min(DIV_ROUND_UP(read_size, max_xfer) * max_xfer,
drivers/nvdimm/label.c- config_size);

Fix this by checking the config size parameter by extending an
existing check.

Classification

CVE ID: CVE-2025-38072

Affected Products

Vendor: Linux

Product: Linux

Exploit Prediction Scoring System (EPSS)

EPSS Score: 0.02% (probability of being exploited)

EPSS Percentile: 5.03% (scored less or equal to compared to others)

EPSS Date: 2025-06-22 (when was this score calculated)

References

Timeline

2025-06-18 10:40:19 UTC
CVE

libnvdimm/labels: Fix divide error in nd_label_data_init()