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Mon, 31 Aug 2026 17:29:41 -0700 (PDT) Received: from 4470NRD-ASU.ssi.samsung.com ([50.205.20.42]) by smtp.gmail.com with ESMTPSA id 00721157ae682-85e668ce7ecsm63349177b3.34.2026.08.31.17.29.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 31 Aug 2026 17:29:41 -0700 (PDT) From: Anisa Su X-Google-Original-From: Anisa Su To: linux-cxl@vger.kernel.org Cc: benjamin.cheatham@amd.com, icheng@nvidia.com, dave@stgolabs.net, dave.jiang@intel.com, alison.schofield@intel.com, jic23@kernel.org, Anisa Su Subject: [PATCH v2 2/4] cxl/events: Validate the record count reported by the device Date: Mon, 31 Aug 2026 17:26:55 -0700 Message-ID: <20260901002912.958-3-anisa.su@samsung.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260901002912.958-1-anisa.su@samsung.com> References: <20260901002912.958-1-anisa.su@samsung.com> Precedence: bulk X-Mailing-List: linux-cxl@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit cxl_mem_get_records_log() takes the record count straight out of the Get Event Records payload and uses it to read from payload->records[]. An oversized count reads past that buffer. Both __cxl_event_trace_record() and cxl_clear_event_record() use the record count to iterate oer payload->records[]. Bound the count by mbox_cmd.size_out which is already sanitized by __cxl_pci_mbox_send_cmd(). Report a bad record count as an error rather than a drained log, so a device repeating the bad count does not keep the event thread re-reading it. Fixes: 6ebe28f9ec72 ("cxl/mem: Read, trace, and clear events on driver load") Signed-off-by: Anisa Su --- drivers/cxl/core/mbox.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/drivers/cxl/core/mbox.c b/drivers/cxl/core/mbox.c index 2b71a8e1f35f..02b8c33a74b6 100644 --- a/drivers/cxl/core/mbox.c +++ b/drivers/cxl/core/mbox.c @@ -1110,6 +1110,14 @@ static int cxl_mem_get_records_log(struct cxl_memdev_state *mds, nr_rec = le16_to_cpu(payload->record_count); if (!nr_rec) break; + + if (struct_size(payload, records, nr_rec) > mbox_cmd.size_out) { + dev_err_ratelimited(dev, + "Event log '%d': record count %u mismatch in %zu byte payload", + type, nr_rec, mbox_cmd.size_out); + rc = -EIO; + break; + } *got_records = true; for (i = 0; i < nr_rec; i++) -- 2.43.0