From b080a9f09881d513837b579b1952f41cecec4e63 Mon Sep 17 00:00:00 2001 From: Sudarsan Ramesh Date: Tue, 3 Nov 2020 17:52:12 -0500 Subject: disp: msm: dp: validate edid before dereferencing Currently, when using custom edid from debugfs, the extensions data inside the edid block is not validated before dereferencing the extension block. The fix adds a edid validation function to validate any custom edids before accessing any members in the edid block. Change-Id: I8a2cc45477416a8f8c4cff882bd53d14012e29f4 Signed-off-by: Sudarsan Ramesh --- msm/dp/dp_debug.c | 4 ++-- msm/dp/dp_panel.c | 23 +++++++++++++++++++++-- msm/dp/dp_panel.h | 2 +- 3 files changed, 24 insertions(+), 5 deletions(-) diff --git a/msm/dp/dp_debug.c b/msm/dp/dp_debug.c index 0459adce..6303c1cf 100644 --- a/msm/dp/dp_debug.c +++ b/msm/dp/dp_debug.c @@ -154,7 +154,7 @@ static ssize_t dp_debug_write_edid(struct file *file, edid = debug->edid; bail: kfree(buf); - debug->panel->set_edid(debug->panel, edid); + debug->panel->set_edid(debug->panel, edid, debug->edid_size); /* * print edid status as this code is executed @@ -1628,7 +1628,7 @@ static void dp_debug_set_sim_mode(struct dp_debug_private *debug, bool sim) debug->aux->set_sim_mode(debug->aux, false, NULL, NULL); debug->dp_debug.sim_mode = false; - debug->panel->set_edid(debug->panel, 0); + debug->panel->set_edid(debug->panel, 0, 0); if (debug->edid) { devm_kfree(debug->dev, debug->edid); debug->edid = NULL; diff --git a/msm/dp/dp_panel.c b/msm/dp/dp_panel.c index 74f915b5..1c01b0ee 100644 --- a/msm/dp/dp_panel.c +++ b/msm/dp/dp_panel.c @@ -7,6 +7,7 @@ #include #include #include "dp_debug.h" +#include #define DP_KHZ_TO_HZ 1000 #define DP_PANEL_DEFAULT_BPP 24 @@ -1937,7 +1938,25 @@ static int dp_panel_set_default_link_params(struct dp_panel *dp_panel) return 0; } -static int dp_panel_set_edid(struct dp_panel *dp_panel, u8 *edid) +static bool dp_panel_validate_edid(struct edid *edid, size_t edid_size) +{ + if (!edid || (edid_size < EDID_LENGTH)) + return false; + + if (EDID_LENGTH * (edid->extensions + 1) > edid_size) { + DP_ERR("edid size does not match allocated.\n"); + return false; + } + + if (!drm_edid_is_valid(edid)) { + DP_ERR("invalid edid.\n"); + return false; + } + return true; +} + +static int dp_panel_set_edid(struct dp_panel *dp_panel, u8 *edid, + size_t edid_size) { struct dp_panel_private *panel; @@ -1948,7 +1967,7 @@ static int dp_panel_set_edid(struct dp_panel *dp_panel, u8 *edid) panel = container_of(dp_panel, struct dp_panel_private, dp_panel); - if (edid) { + if (edid && dp_panel_validate_edid((struct edid *)edid, edid_size)) { dp_panel->edid_ctrl->edid = (struct edid *)edid; panel->custom_edid = true; } else { diff --git a/msm/dp/dp_panel.h b/msm/dp/dp_panel.h index dbc5ba98..36629c3c 100644 --- a/msm/dp/dp_panel.h +++ b/msm/dp/dp_panel.h @@ -146,7 +146,7 @@ struct dp_panel { int (*get_modes)(struct dp_panel *dp_panel, struct drm_connector *connector, struct dp_display_mode *mode); void (*handle_sink_request)(struct dp_panel *dp_panel); - int (*set_edid)(struct dp_panel *dp_panel, u8 *edid); + int (*set_edid)(struct dp_panel *dp_panel, u8 *edid, size_t edid_size); int (*set_dpcd)(struct dp_panel *dp_panel, u8 *dpcd); int (*setup_hdr)(struct dp_panel *dp_panel, struct drm_msm_ext_hdr_metadata *hdr_meta, -- cgit v1.2.3