From: Ville Syrjälä ville.syrjala@linux.intel.com
Throw out the magic '5' from validate_displayid() and replace with the actual thing we mean sizeof(header)+checksum. Also rewrite the checksum loop to be less hard to parse for mere mortals.
Signed-off-by: Ville Syrjälä ville.syrjala@linux.intel.com --- drivers/gpu/drm/drm_edid.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-)
diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c index f1ba06396c0a..185027f751f6 100644 --- a/drivers/gpu/drm/drm_edid.c +++ b/drivers/gpu/drm/drm_edid.c @@ -5098,7 +5098,7 @@ u32 drm_add_display_info(struct drm_connector *connector, const struct edid *edi
static int validate_displayid(u8 *displayid, int length, int idx) { - int i; + int i, dispid_length; u8 csum = 0; struct displayid_hdr *base;
@@ -5107,15 +5107,18 @@ static int validate_displayid(u8 *displayid, int length, int idx) DRM_DEBUG_KMS("base revision 0x%x, length %d, %d %d\n", base->rev, base->bytes, base->prod_id, base->ext_count);
- if (base->bytes + 5 > length - idx) + /* +1 for DispID checksum */ + dispid_length = sizeof(*base) + base->bytes + 1; + if (dispid_length > length - idx) return -EINVAL; - for (i = idx; i <= base->bytes + 5; i++) { - csum += displayid[i]; - } + + for (i = 0; i < dispid_length; i++) + csum += displayid[idx + i]; if (csum) { DRM_NOTE("DisplayID checksum invalid, remainder is %d\n", csum); return -EINVAL; } + return 0; }