[media] v4l2-dv-timings: add sanity checks in cvt,gtf calculations

Wrong values of hfreq and image height can lead to strange timings.
Avoid timing calculations for such values.

Suggested By: Martin Bugge <marbugge@cisco.com>

Cc: Martin Bugge <marbugge@cisco.com>
Signed-off-by: Prashant Laddha <prladdha@cisco.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

diff --git a/drivers/media/v4l2-core/v4l2-dv-timings.c b/drivers/media/v4l2-core/v4l2-dv-timings.c
index 16c8ac5b5e0b439bd5be77ced4baff2addc10d42..4e09792038ed01484700c368c0d6eabe18048a94 100644 (file)
--- a/drivers/media/v4l2-core/v4l2-dv-timings.c
+++ b/drivers/media/v4l2-core/v4l2-dv-timings.c
@@ -365,6 +365,9 @@ bool v4l2_detect_cvt(unsigned frame_height, unsigned hfreq, unsigned vsync,
        else
                return false;
 
+       if (hfreq == 0)
+               return false;
+
        /* Vertical */
        if (reduced_blanking) {
                v_fp = CVT_RB_V_FPORCH;
@@ -382,6 +385,9 @@ bool v4l2_detect_cvt(unsigned frame_height, unsigned hfreq, unsigned vsync,
        }
        image_height = (frame_height - v_fp - vsync - v_bp + 1) & ~0x1;
 
+       if (image_height < 0)
+               return false;
+
        /* Aspect ratio based on vsync */
        switch (vsync) {
        case 4:
@@ -527,12 +533,18 @@ bool v4l2_detect_gtf(unsigned frame_height,
        else
                return false;
 
+       if (hfreq == 0)
+               return false;
+
        /* Vertical */
        v_fp = GTF_V_FP;
 
        v_bp = (GTF_MIN_VSYNC_BP * hfreq + 500000) / 1000000 - vsync;
        image_height = (frame_height - v_fp - vsync - v_bp + 1) & ~0x1;
 
+       if (image_height < 0)
+               return false;
+
        if (aspect.numerator == 0 || aspect.denominator == 0) {
                aspect.numerator = 16;
                aspect.denominator = 9;