[PATCH 6.18 077/175] HID: Intel-thc-hid: Intel-thc: Add safety check for reading DMA buffer

Greg Kroah-Hartman
2026-02-09T14:29:21Z

From: Even Xu <even.xu@intel.com>

[ Upstream commit a9a917998d172ec117f9e9de1919174153c0ace4 ]

Add DMA buffer readiness check before reading DMA buffer to avoid
unexpected NULL pointer accessing.

Signed-off-by: Even Xu <even.xu@intel.com>
Tested-by: Rui Zhang <rui1.zhang@intel.com>
Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/hid/intel-thc-hid/intel-thc/intel-thc-dma.c | 5 +++++
1 file changed, 5 insertions(+)

diff --git a/drivers/hid/intel-thc-hid/intel-thc/intel-thc-dma.c b/drivers/hid/intel-thc-hid/intel-thc/intel-thc-dma.c
index a0c368aa7979c..6ee675e0a7384 100644
--- a/drivers/hid/intel-thc-hid/intel-thc/intel-thc-dma.c
+++ b/drivers/hid/intel-thc-hid/intel-thc/intel-thc-dma.c
@@ -575,6 +575,11 @@ static int read_dma_buffer(struct thc_device *dev,
return -EINVAL;
}

+ if (!read_config->prd_tbls || !read_config->sgls[prd_table_index]) {
+ dev_err_once(dev->dev, "PRD tables are not ready yet\n");
+ return -EINVAL;
+ }
+
prd_tbl = &read_config->prd_tbls[prd_table_index];
mes_len = calc_message_len(prd_tbl, &nent);
if (mes_len > read_config->max_packet_size) {
--
2.51.0