v4l2-ctl: qc.nr_of_dims is 0 for strings, check this

The string type doesn't use dimensions, so nr_of_dims is 0 which
means that using nr_of_dims - 1 as an index in an array is a bad
idea.

Put that code under an 'if (qc.nr_of_dims)' to avoid a bus error.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>

1 files changed, 7 insertions, 5 deletions

diff --git a/utils/v4l2-ctl/v4l2-ctl-common.cpp b/utils/v4l2-ctl/v4l2-ctl-common.cpp
index 4ca1b834..60624750 100644
--- a/utils/v4l2-ctl/v4l2-ctl-common.cpp
+++ b/utils/v4l2-ctl/v4l2-ctl-common.cpp
@@ -844,11 +844,13 @@ void common_set(int fd)
 				if (fill_subset(qc, subset))
 					return;
 
-				divide[qc.nr_of_dims - 1] = 1;
-				for (d = 0; d < qc.nr_of_dims - 1; d++) {
-					divide[d] = qc.dims[d + 1];
-					for (i = 0; i < d; i++)
-						divide[i] *= divide[d];
+				if (qc.nr_of_dims) {
+					divide[qc.nr_of_dims - 1] = 1;
+					for (d = 0; d < qc.nr_of_dims - 1; d++) {
+						divide[d] = qc.dims[d + 1];
+						for (i = 0; i < d; i++)
+							divide[i] *= divide[d];
+					}
 				}