linux-kernel - [PATCH 5.10/5.15/6.1] drm/amd/display: Avoid overflow assignment in link_dp

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Message-ID: <20250328052512.1206068-1-sdl@nppct.ru>
Date: Fri, 28 Mar 2025 05:25:11 +0000
From: Alexey Nepomnyashih <sdl@...ct.ru>
To: Harry Wentland <harry.wentland@....com>
Cc: Alexey Nepomnyashih <sdl@...ct.ru>,
	Leo Li <sunpeng.li@....com>,
	Alex Deucher <alexander.deucher@....com>,
	Christian König <christian.koenig@....com>,
	David Airlie <airlied@...ux.ie>,
	Daniel Vetter <daniel@...ll.ch>,
	amd-gfx@...ts.freedesktop.org,
	dri-devel@...ts.freedesktop.org,
	linux-kernel@...r.kernel.org,
	lvc-project@...uxtesting.org,
	Alex Hung <alex.hung@....com>,
	Wenjing Liu <wenjing.liu@....com>,
	Daniel Wheeler <daniel.wheeler@....com>,
	Rodrigo Siqueira <rodrigo.siqueira@....com>
Subject: [PATCH 5.10/5.15/6.1] drm/amd/display: Avoid overflow assignment in link_dp_cts

From: Alex Hung <alex.hung@....com>

commit a15268787b79fd183dd526cc16bec9af4f4e49a1 upstream.

sampling_rate is an uint8_t but is assigned an unsigned int, and thus it
can overflow. As a result, sampling_rate is changed to uint32_t.

Similarly, LINK_QUAL_PATTERN_SET has a size of 2 bits, and it should
only be assigned to a value less or equal than 4.

This fixes 2 INTEGER_OVERFLOW issues reported by Coverity.

Signed-off-by: Alex Hung <alex.hung@....com>
Reviewed-by: Wenjing Liu <wenjing.liu@....com>
Tested-by: Daniel Wheeler <daniel.wheeler@....com>
Signed-off-by: Rodrigo Siqueira <rodrigo.siqueira@....com>
Signed-off-by: Alex Deucher <alexander.deucher@....com>
[ Alexey Nepomnyashih: backport fix dc_link_dp_set_test_pattern()
 to dc_link_dp.c. ]
Signed-off-by: Alexey Nepomnyashih <sdl@...ct.ru>
---
 drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c | 3 ++-
 drivers/gpu/drm/amd/display/dc/dc_dp_types.h     | 2 +-
 drivers/gpu/drm/amd/display/include/dpcd_defs.h  | 1 +
 3 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c b/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
index 82b747c0ed69..4a70cbd05bd9 100644
--- a/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
@@ -6159,7 +6159,8 @@ bool dc_link_dp_set_test_pattern(
 			core_link_read_dpcd(link, DP_TRAINING_PATTERN_SET,
 					    &training_pattern.raw,
 					    sizeof(training_pattern));
-			training_pattern.v1_3.LINK_QUAL_PATTERN_SET = pattern;
+			if (pattern <= PHY_TEST_PATTERN_END_DP11)
+				training_pattern.v1_3.LINK_QUAL_PATTERN_SET = pattern;
 			core_link_write_dpcd(link, DP_TRAINING_PATTERN_SET,
 					     &training_pattern.raw,
 					     sizeof(training_pattern));
diff --git a/drivers/gpu/drm/amd/display/dc/dc_dp_types.h b/drivers/gpu/drm/amd/display/dc/dc_dp_types.h
index 296793d8b2bf..6703be2fc157 100644
--- a/drivers/gpu/drm/amd/display/dc/dc_dp_types.h
+++ b/drivers/gpu/drm/amd/display/dc/dc_dp_types.h
@@ -715,7 +715,7 @@ struct dp_audio_test_data_flags {
 struct dp_audio_test_data {
 
 	struct dp_audio_test_data_flags flags;
-	uint8_t sampling_rate;
+	uint32_t sampling_rate;
 	uint8_t channel_count;
 	uint8_t pattern_type;
 	uint8_t pattern_period[8];
diff --git a/drivers/gpu/drm/amd/display/include/dpcd_defs.h b/drivers/gpu/drm/amd/display/include/dpcd_defs.h
index b2df07f9e91c..1b073e9e7b11 100644
--- a/drivers/gpu/drm/amd/display/include/dpcd_defs.h
+++ b/drivers/gpu/drm/amd/display/include/dpcd_defs.h
@@ -76,6 +76,7 @@ enum dpcd_phy_test_patterns {
 	PHY_TEST_PATTERN_D10_2,
 	PHY_TEST_PATTERN_SYMBOL_ERROR,
 	PHY_TEST_PATTERN_PRBS7,
+	PHY_TEST_PATTERN_END_DP11 = PHY_TEST_PATTERN_PRBS7,
 	PHY_TEST_PATTERN_80BIT_CUSTOM,/* For DP1.2 only */
 	PHY_TEST_PATTERN_CP2520_1,
 	PHY_TEST_PATTERN_CP2520_2,
-- 
2.43.0