From: Robert Richter <rrichter@amd.com> stable inclusion from stable-v6.6.93 commit ea3d95e05e97ea20fd6513f647393add16fce3b2 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/ICGAEE CVE: CVE-2025-38072 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- [ Upstream commit ef1d3455bbc1922f94a91ed58d3d7db440652959 ] 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. Signed-off-by: Robert Richter <rrichter@amd.com> Reviewed-by: Pankaj Gupta <pankaj.gupta@amd.com> Reviewed-by: Ira Weiny <ira.weiny@intel.com> Link: https://patch.msgid.link/20250320112223.608320-1-rrichter@amd.com Signed-off-by: Ira Weiny <ira.weiny@intel.com> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Wang Tao <wangtao554@huawei.com> --- drivers/nvdimm/label.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/nvdimm/label.c b/drivers/nvdimm/label.c index 082253a3a956..04f4a049599a 100644 --- a/drivers/nvdimm/label.c +++ b/drivers/nvdimm/label.c @@ -442,7 +442,8 @@ int nd_label_data_init(struct nvdimm_drvdata *ndd) if (ndd->data) return 0; - if (ndd->nsarea.status || ndd->nsarea.max_xfer == 0) { + if (ndd->nsarea.status || ndd->nsarea.max_xfer == 0 || + ndd->nsarea.config_size == 0) { dev_dbg(ndd->dev, "failed to init config data area: (%u:%u)\n", ndd->nsarea.max_xfer, ndd->nsarea.config_size); return -ENXIO; -- 2.34.1