From: Ville Syrjala <ville.syrjala@linux.intel.com>
To: dri-devel@lists.freedesktop.org
Cc: intel-gfx@lists.freedesktop.org
Subject: [Intel-gfx] [PATCH 8/9] drm/edid: Clarify validate_displayid()
Date: Fri, 13 Mar 2020 18:20:53 +0200 [thread overview]
Message-ID: <20200313162054.16009-9-ville.syrjala@linux.intel.com> (raw)
In-Reply-To: <20200313162054.16009-1-ville.syrjala@linux.intel.com>
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;
}
--
2.24.1
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next prev parent reply other threads:[~2020-03-13 16:21 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-13 16:20 [Intel-gfx] [PATCH 0/9] drm/edid: DisplayID parser fixes Ville Syrjala
2020-03-13 16:20 ` [Intel-gfx] [PATCH 1/9] drm: Constify topology id Ville Syrjala
2020-03-13 20:05 ` Alex Deucher
2020-03-18 15:56 ` Ville Syrjälä
2020-03-13 16:20 ` [Intel-gfx] [PATCH 2/9] drm/edid: Swap some operands in for_each_displayid_db() Ville Syrjala
2020-03-13 16:20 ` [Intel-gfx] [PATCH 3/9] drm/edid: Remove idx==1 assumptions from all over the DispID parsing Ville Syrjala
2020-03-13 16:20 ` [Intel-gfx] [PATCH 4/9] drm/edid: Return DispID length from drm_find_displayid_extension() Ville Syrjala
2020-03-13 16:20 ` [Intel-gfx] [PATCH 5/9] drm/edid: Move validate_displayid() drm_find_displayid_extension() Ville Syrjala
2020-03-13 16:20 ` [Intel-gfx] [PATCH 6/9] drm/edid: Don't parse garbage as DispID blocks Ville Syrjala
2020-03-13 16:20 ` [Intel-gfx] [PATCH 7/9] drm/edid: Don't include ext block csum in DispID size Ville Syrjala
2020-03-13 16:20 ` Ville Syrjala [this message]
2020-03-13 16:20 ` [Intel-gfx] [PATCH 9/9] drm/edid: Fix DispID tile parsing for override EDID Ville Syrjala
2020-03-16 14:44 ` [Intel-gfx] ✓ Fi.CI.BAT: success for drm/edid: DisplayID parser fixes Patchwork
2020-03-16 21:44 ` [Intel-gfx] ✗ Fi.CI.IGT: failure " Patchwork
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