[PATCH v4 2/2] nvme: validate FDP configuration descriptor sizes

[liuxixin]

Validate descriptor sizes while walking the FDP configurations log so
dsze == 0 or a descriptor past the log end cannot cause unbounded
iteration or reads past the buffer.

Reviewed-by: Nitesh Shetty <nj.shetty at samsung.com>
Reviewed-by: Christoph Hellwig <hch at lst.de>
Signed-off-by: liuxixin <gliuxen at gmail.com>
---
 drivers/nvme/host/core.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 766157ba6..40e87b563 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -2275,7 +2275,15 @@ static int nvme_query_fdp_granularity(struct nvme_ctrl *ctrl,
 	desc = log;
 	end = log + size - sizeof(*h);
 	for (i = 0; i < fdp_idx; i++) {
-		log += le16_to_cpu(desc->dsze);
+		u16 dsze = le16_to_cpu(desc->dsze);
+
+		if (!dsze || log + dsze > end) {
+			dev_warn(ctrl->device,
+				 "FDP invalid config descriptor at index %d\n", i);
+			ret = 0;
+			goto out;
+		}
+		log += dsze;
 		desc = log;
 		if (log >= end) {
 			dev_warn(ctrl->device,
-- 
2.43.0