-----Original Message----- From: dri-devel dri-devel-bounces@lists.freedesktop.org On Behalf Of Alex Deucher Sent: Tuesday, January 28, 2020 4:04 AM To: Ville Syrjala ville.syrjala@linux.intel.com Cc: Allen Chen allen.chen@ite.com.tw; Intel Graphics Development <intel- gfx@lists.freedesktop.org>; Maling list - DRI developers <dri- devel@lists.freedesktop.org> Subject: Re: [PATCH 1/8] drm/edid: Check the number of detailed timing descriptors in the CEA ext block
On Fri, Jan 24, 2020 at 3:03 PM Ville Syrjala ville.syrjala@linux.intel.com wrote:
From: Ville Syrjälä ville.syrjala@linux.intel.com
CEA-861 says : "d = offset for the byte following the reserved data block. If no data is provided in the reserved data block, then d=4. If no DTDs are provided, then d=0."
So let's not look for DTDs when d==0. In fact let's just make that <4 since those values would just mean that he DTDs overlap the block header. And let's also check that d isn't so big as to declare the descriptors to live past the block end, although the code does already survive that case as we'd just end up with a negative number of descriptors and the loop would not do anything.
Cc: Allen Chen allen.chen@ite.com.tw Signed-off-by: Ville Syrjälä ville.syrjala@linux.intel.com
Acked-by: Alex Deucher alexander.deucher@amd.com
Looks good to me as well. Reviewed-by: Uma Shankar uma.shankar@intel.com
drivers/gpu/drm/drm_edid.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c index 99769d6c9f84..1b6e544cf5c7 100644 --- a/drivers/gpu/drm/drm_edid.c +++ b/drivers/gpu/drm/drm_edid.c @@ -2201,10 +2201,13 @@ typedef void detailed_cb(struct detailed_timing *timing, void *closure); static void cea_for_each_detailed_block(u8 *ext, detailed_cb *cb, void *closure) {
int i, n = 0;
int i, n; u8 d = ext[0x02]; u8 *det_base = ext + d;if (d < 4 || d > 127)return;n = (127 - d) / 18; for (i = 0; i < n; i++) cb((struct detailed_timing *)(det_base + 18 * i),closure);
2.24.1
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