releases/6.7.9/drm-amd-display-prevent-potential-buffer-overflow-in.patch

From e8ade91757eaf66bd2dcbc6e07ec3ed9c6942129 Mon Sep 17 00:00:00 2001
From: Sasha Levin <sashal@kernel.org>
Date: Tue, 20 Feb 2024 09:14:25 +0530
Subject: drm/amd/display: Prevent potential buffer overflow in
 map_hw_resources

From: Srinivasan Shanmugam <srinivasan.shanmugam@amd.com>

[ Upstream commit 0f8ca019544a252d1afb468ce840c6dcbac73af4 ]

Adds a check in the map_hw_resources function to prevent a potential
buffer overflow. The function was accessing arrays using an index that
could potentially be greater than the size of the arrays, leading to a
buffer overflow.

Adds a check to ensure that the index is within the bounds of the
arrays. If the index is out of bounds, an error message is printed and
break it will continue execution with just ignoring extra data early to
prevent the buffer overflow.

Reported by smatch:
drivers/gpu/drm/amd/amdgpu/../display/dc/dml2/dml2_wrapper.c:79 map_hw_resources() error: buffer overflow 'dml2->v20.scratch.dml_to_dc_pipe_mapping.disp_cfg_to_stream_id' 6 <= 7
drivers/gpu/drm/amd/amdgpu/../display/dc/dml2/dml2_wrapper.c:81 map_hw_resources() error: buffer overflow 'dml2->v20.scratch.dml_to_dc_pipe_mapping.disp_cfg_to_plane_id' 6 <= 7

Fixes: 7966f319c66d ("drm/amd/display: Introduce DML2")
Cc: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Cc: Roman Li <roman.li@amd.com>
Cc: Qingqing Zhuo <Qingqing.Zhuo@amd.com>
Cc: Aurabindo Pillai <aurabindo.pillai@amd.com>
Cc: Tom Chung <chiahsuan.chung@amd.com>
Signed-off-by: Srinivasan Shanmugam <srinivasan.shanmugam@amd.com>
Suggested-by: Roman Li <roman.li@amd.com>
Reviewed-by: Roman Li <roman.li@amd.com>
Reviewed-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/gpu/drm/amd/display/dc/dml2/dml2_wrapper.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/gpu/drm/amd/display/dc/dml2/dml2_wrapper.c b/drivers/gpu/drm/amd/display/dc/dml2/dml2_wrapper.c
index 8f231418870f2..c62b61ac45d27 100644
--- a/drivers/gpu/drm/amd/display/dc/dml2/dml2_wrapper.c
+++ b/drivers/gpu/drm/amd/display/dc/dml2/dml2_wrapper.c
@@ -76,6 +76,11 @@ static void map_hw_resources(struct dml2_context *dml2,
 			in_out_display_cfg->hw.DLGRefClkFreqMHz = 50;
 		}
 		for (j = 0; j < mode_support_info->DPPPerSurface[i]; j++) {
+			if (i >= __DML2_WRAPPER_MAX_STREAMS_PLANES__) {
+				dml_print("DML::%s: Index out of bounds: i=%d, __DML2_WRAPPER_MAX_STREAMS_PLANES__=%d\n",
+					  __func__, i, __DML2_WRAPPER_MAX_STREAMS_PLANES__);
+				break;
+			}
 			dml2->v20.scratch.dml_to_dc_pipe_mapping.dml_pipe_idx_to_stream_id[num_pipes] = dml2->v20.scratch.dml_to_dc_pipe_mapping.disp_cfg_to_stream_id[i];
 			dml2->v20.scratch.dml_to_dc_pipe_mapping.dml_pipe_idx_to_stream_id_valid[num_pipes] = true;
 			dml2->v20.scratch.dml_to_dc_pipe_mapping.dml_pipe_idx_to_plane_id[num_pipes] = dml2->v20.scratch.dml_to_dc_pipe_mapping.disp_cfg_to_plane_id[i];
-- 
2.43.0