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authorVille Syrjälä <ville.syrjala@linux.intel.com>2020-01-24 23:02:25 +0300
committerVille Syrjälä <ville.syrjala@linux.intel.com>2020-02-15 00:34:16 +0300
commita7a131ac18a23d31f572cac4cd20581e56add932 (patch)
tree69d03063050ce8cd1a019b067fb449940483c338 /drivers/gpu/drm/drm_edid.c
parent7304b9810a7367131dc26ced61696e7c98dd6666 (diff)
downloadlinux-a7a131ac18a23d31f572cac4cd20581e56add932.tar.xz
drm/edid: Don't accept any old garbage as a display descriptor
Currently we assume any 18 byte descriptor to be a display descritor if only the tag byte matches the expected value. But for detailed timing descriptors that same byte is just the lower 8 bits of hblank, and as such can match any display descriptor tag. To properly validate that the 18 byte descriptor is in fact a display descriptor we must also examine bytes 0-2 (just byte 1 should actually suffice but the spec does say that bytes 0 and 2 must also always be zero for display descriptors so we check those too). Unlike Allen's original proposed patch to just fix is_rb() we roll this out across the board to fix everything. Cc: Allen Chen <allen.chen@ite.com.tw> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20200124200231.10517-2-ville.syrjala@linux.intel.com Acked-by: Alex Deucher <alexander.deucher@amd.com> Reviewed-by: Uma Shankar <uma.shankar@intel.com>
Diffstat (limited to 'drivers/gpu/drm/drm_edid.c')
-rw-r--r--drivers/gpu/drm/drm_edid.c65
1 files changed, 41 insertions, 24 deletions
diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index 3fb280837fdb..e878b0c839a0 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -2212,6 +2212,12 @@ struct drm_display_mode *drm_mode_find_dmt(struct drm_device *dev,
}
EXPORT_SYMBOL(drm_mode_find_dmt);
+static bool is_display_descriptor(const u8 d[18], u8 tag)
+{
+ return d[0] == 0x00 && d[1] == 0x00 &&
+ d[2] == 0x00 && d[3] == tag;
+}
+
typedef void detailed_cb(struct detailed_timing *timing, void *closure);
static void
@@ -2273,9 +2279,12 @@ static void
is_rb(struct detailed_timing *t, void *data)
{
u8 *r = (u8 *)t;
- if (r[3] == EDID_DETAIL_MONITOR_RANGE)
- if (r[15] & 0x10)
- *(bool *)data = true;
+
+ if (!is_display_descriptor(r, EDID_DETAIL_MONITOR_RANGE))
+ return;
+
+ if (r[15] & 0x10)
+ *(bool *)data = true;
}
/* EDID 1.4 defines this explicitly. For EDID 1.3, we guess, badly. */
@@ -2295,7 +2304,11 @@ static void
find_gtf2(struct detailed_timing *t, void *data)
{
u8 *r = (u8 *)t;
- if (r[3] == EDID_DETAIL_MONITOR_RANGE && r[10] == 0x02)
+
+ if (!is_display_descriptor(r, EDID_DETAIL_MONITOR_RANGE))
+ return;
+
+ if (r[10] == 0x02)
*(u8 **)data = r;
}
@@ -2834,7 +2847,7 @@ do_inferred_modes(struct detailed_timing *timing, void *c)
struct detailed_non_pixel *data = &timing->data.other_data;
struct detailed_data_monitor_range *range = &data->data.range;
- if (data->type != EDID_DETAIL_MONITOR_RANGE)
+ if (!is_display_descriptor((const u8 *)timing, EDID_DETAIL_MONITOR_RANGE))
return;
closure->modes += drm_dmt_modes_for_range(closure->connector,
@@ -2913,10 +2926,11 @@ static void
do_established_modes(struct detailed_timing *timing, void *c)
{
struct detailed_mode_closure *closure = c;
- struct detailed_non_pixel *data = &timing->data.other_data;
- if (data->type == EDID_DETAIL_EST_TIMINGS)
- closure->modes += drm_est3_modes(closure->connector, timing);
+ if (!is_display_descriptor((const u8 *)timing, EDID_DETAIL_EST_TIMINGS))
+ return;
+
+ closure->modes += drm_est3_modes(closure->connector, timing);
}
/**
@@ -2965,19 +2979,19 @@ do_standard_modes(struct detailed_timing *timing, void *c)
struct detailed_non_pixel *data = &timing->data.other_data;
struct drm_connector *connector = closure->connector;
struct edid *edid = closure->edid;
+ int i;
- if (data->type == EDID_DETAIL_STD_MODES) {
- int i;
- for (i = 0; i < 6; i++) {
- struct std_timing *std;
- struct drm_display_mode *newmode;
+ if (!is_display_descriptor((const u8 *)timing, EDID_DETAIL_STD_MODES))
+ return;
- std = &data->data.timings[i];
- newmode = drm_mode_std(connector, edid, std);
- if (newmode) {
- drm_mode_probed_add(connector, newmode);
- closure->modes++;
- }
+ for (i = 0; i < 6; i++) {
+ struct std_timing *std = &data->data.timings[i];
+ struct drm_display_mode *newmode;
+
+ newmode = drm_mode_std(connector, edid, std);
+ if (newmode) {
+ drm_mode_probed_add(connector, newmode);
+ closure->modes++;
}
}
}
@@ -3072,10 +3086,11 @@ static void
do_cvt_mode(struct detailed_timing *timing, void *c)
{
struct detailed_mode_closure *closure = c;
- struct detailed_non_pixel *data = &timing->data.other_data;
- if (data->type == EDID_DETAIL_CVT_3BYTE)
- closure->modes += drm_cvt_modes(closure->connector, timing);
+ if (!is_display_descriptor((const u8 *)timing, EDID_DETAIL_CVT_3BYTE))
+ return;
+
+ closure->modes += drm_cvt_modes(closure->connector, timing);
}
static int
@@ -4301,8 +4316,10 @@ drm_parse_hdmi_vsdb_audio(struct drm_connector *connector, const u8 *db)
static void
monitor_name(struct detailed_timing *t, void *data)
{
- if (t->data.other_data.type == EDID_DETAIL_MONITOR_NAME)
- *(u8 **)data = t->data.other_data.data.str.str;
+ if (!is_display_descriptor((const u8 *)t, EDID_DETAIL_MONITOR_NAME))
+ return;
+
+ *(u8 **)data = t->data.other_data.data.str.str;
}
static int get_monitor_name(struct edid *edid, char name[13])