Patch "drm/amd/display: Implement bounds check for stream encoder creation in DCN301" has been added to the 5.15-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    drm/amd/display: Implement bounds check for stream encoder creation in DCN301

to the 5.15-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     drm-amd-display-implement-bounds-check-for-stream-en.patch
and it can be found in the queue-5.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit f7e00e77a4ee1177eb873dab720b0322a7349451
Author: Srinivasan Shanmugam <srinivasan.shanmugam@xxxxxxx>
Date:   Wed Feb 7 10:20:57 2024 +0530

    drm/amd/display: Implement bounds check for stream encoder creation in DCN301
    
    [ Upstream commit 58fca355ad37dcb5f785d9095db5f748b79c5dc2 ]
    
    'stream_enc_regs' array is an array of dcn10_stream_enc_registers
    structures. The array is initialized with four elements, corresponding
    to the four calls to stream_enc_regs() in the array initializer. This
    means that valid indices for this array are 0, 1, 2, and 3.
    
    The error message 'stream_enc_regs' 4 <= 5 below, is indicating that
    there is an attempt to access this array with an index of 5, which is
    out of bounds. This could lead to undefined behavior
    
    Here, eng_id is used as an index to access the stream_enc_regs array. If
    eng_id is 5, this would result in an out-of-bounds access on the
    stream_enc_regs array.
    
    Thus fixing Buffer overflow error in dcn301_stream_encoder_create
    reported by Smatch:
    drivers/gpu/drm/amd/amdgpu/../display/dc/resource/dcn301/dcn301_resource.c:1011 dcn301_stream_encoder_create() error: buffer overflow 'stream_enc_regs' 4 <= 5
    
    Fixes: 3a83e4e64bb1 ("drm/amd/display: Add dcn3.01 support to DC (v2)")
    Cc: Roman Li <Roman.Li@xxxxxxx>
    Cc: Rodrigo Siqueira <Rodrigo.Siqueira@xxxxxxx>
    Cc: Aurabindo Pillai <aurabindo.pillai@xxxxxxx>
    Signed-off-by: Srinivasan Shanmugam <srinivasan.shanmugam@xxxxxxx>
    Reviewed-by: Roman Li <roman.li@xxxxxxx>
    Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/gpu/drm/amd/display/dc/dcn301/dcn301_resource.c b/drivers/gpu/drm/amd/display/dc/dcn301/dcn301_resource.c
index b6c363b462a7..a24f1c215da9 100644
--- a/drivers/gpu/drm/amd/display/dc/dcn301/dcn301_resource.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn301/dcn301_resource.c
@@ -1195,7 +1195,7 @@ struct stream_encoder *dcn301_stream_encoder_create(
 	vpg = dcn301_vpg_create(ctx, vpg_inst);
 	afmt = dcn301_afmt_create(ctx, afmt_inst);
 
-	if (!enc1 || !vpg || !afmt) {
+	if (!enc1 || !vpg || !afmt || eng_id >= ARRAY_SIZE(stream_enc_regs)) {
 		kfree(enc1);
 		kfree(vpg);
 		kfree(afmt);