In the Linux kernel, the following vulnerability has been resolved:
drm/amd/display: Add null check for set_output_gamma in dcn30_set_output_transfer_func
This commit adds a null check for the set_output_gamma function pointer
in the  dcn30_set_output_transfer_func function. Previously,
set_output_gamma was being checked for nullity at line 386, but then it
was being dereferenced without any nullity check at line 401. This
could potentially lead to a null pointer dereference error if
set_output_gamma is indeed null.
To fix this, we now ensure that set_output_gamma is not null before
dereferencing it. We do this by adding a nullity check for
set_output_gamma before the call to set_output_gamma at line 401. If
set_output_gamma is null, we log an error message and do not call the
function.
This fix prevents a potential null pointer dereference error.
drivers/gpu/drm/amd/amdgpu/../display/dc/hwss/dcn30/dcn30_hwseq.c:401 dcn30_set_output_transfer_func()
error: we previously assumed 'mpc->funcs->set_output_gamma' could be null (see line 386)
drivers/gpu/drm/amd/amdgpu/../display/dc/hwss/dcn30/dcn30_hwseq.c
    373 bool dcn30_set_output_transfer_func(struct dc *dc,
    374                                 struct pipe_ctx *pipe_ctx,
    375                                 const struct dc_stream_state *stream)
    376 {
    377         int mpcc_id = pipe_ctx->plane_res.hubp->inst;
    378         struct mpc *mpc = pipe_ctx->stream_res.opp->ctx->dc->res_pool->mpc;
    379         const struct pwl_params *params = NULL;
    380         bool ret = false;
    381
    382         /* program OGAM or 3DLUT only for the top pipe*/
    383         if (pipe_ctx->top_pipe == NULL) {
    384                 /*program rmu shaper and 3dlut in MPC*/
    385                 ret = dcn30_set_mpc_shaper_3dlut(pipe_ctx, stream);
    386                 if (ret == false && mpc->funcs->set_output_gamma) {
                                            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ If this is NULL
    387                         if (stream->out_transfer_func.type == TF_TYPE_HWPWL)
    388                                 params = &stream->out_transfer_func.pwl;
    389                         else if (pipe_ctx->stream->out_transfer_func.type ==
    390                                         TF_TYPE_DISTRIBUTED_POINTS &&
    391                                         cm3_helper_translate_curve_to_hw_format(
    392                                         &stream->out_transfer_func,
    393                                         &mpc->blender_params, false))
    394                                 params = &mpc->blender_params;
    395                          /* there are no ROM LUTs in OUTGAM */
    396                         if (stream->out_transfer_func.type == TF_TYPE_PREDEFINED)
    397                                 BREAK_TO_DEBUGGER();
    398                 }
    399         }
    400
--> 401         mpc->funcs->set_output_gamma(mpc, mpcc_id, params);
                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Then it will crash
    402         return ret;
    403 }
                
            Metrics
Affected Vendors & Products
References
        History
                    Mon, 03 Nov 2025 23:30:00 +0000
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Wed, 23 Oct 2024 21:15:00 +0000
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         Linux linux Kernel  | 
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| Weaknesses | CWE-476 | |
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products | 
        
        Linux
         Linux linux Kernel  | 
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Mon, 21 Oct 2024 13:15:00 +0000
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Mon, 21 Oct 2024 12:00:00 +0000
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| Description | In the Linux kernel, the following vulnerability has been resolved: drm/amd/display: Add null check for set_output_gamma in dcn30_set_output_transfer_func This commit adds a null check for the set_output_gamma function pointer in the dcn30_set_output_transfer_func function. Previously, set_output_gamma was being checked for nullity at line 386, but then it was being dereferenced without any nullity check at line 401. This could potentially lead to a null pointer dereference error if set_output_gamma is indeed null. To fix this, we now ensure that set_output_gamma is not null before dereferencing it. We do this by adding a nullity check for set_output_gamma before the call to set_output_gamma at line 401. If set_output_gamma is null, we log an error message and do not call the function. This fix prevents a potential null pointer dereference error. drivers/gpu/drm/amd/amdgpu/../display/dc/hwss/dcn30/dcn30_hwseq.c:401 dcn30_set_output_transfer_func() error: we previously assumed 'mpc->funcs->set_output_gamma' could be null (see line 386) drivers/gpu/drm/amd/amdgpu/../display/dc/hwss/dcn30/dcn30_hwseq.c 373 bool dcn30_set_output_transfer_func(struct dc *dc, 374 struct pipe_ctx *pipe_ctx, 375 const struct dc_stream_state *stream) 376 { 377 int mpcc_id = pipe_ctx->plane_res.hubp->inst; 378 struct mpc *mpc = pipe_ctx->stream_res.opp->ctx->dc->res_pool->mpc; 379 const struct pwl_params *params = NULL; 380 bool ret = false; 381 382 /* program OGAM or 3DLUT only for the top pipe*/ 383 if (pipe_ctx->top_pipe == NULL) { 384 /*program rmu shaper and 3dlut in MPC*/ 385 ret = dcn30_set_mpc_shaper_3dlut(pipe_ctx, stream); 386 if (ret == false && mpc->funcs->set_output_gamma) { ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ If this is NULL 387 if (stream->out_transfer_func.type == TF_TYPE_HWPWL) 388 params = &stream->out_transfer_func.pwl; 389 else if (pipe_ctx->stream->out_transfer_func.type == 390 TF_TYPE_DISTRIBUTED_POINTS && 391 cm3_helper_translate_curve_to_hw_format( 392 &stream->out_transfer_func, 393 &mpc->blender_params, false)) 394 params = &mpc->blender_params; 395 /* there are no ROM LUTs in OUTGAM */ 396 if (stream->out_transfer_func.type == TF_TYPE_PREDEFINED) 397 BREAK_TO_DEBUGGER(); 398 } 399 } 400 --> 401 mpc->funcs->set_output_gamma(mpc, mpcc_id, params); ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Then it will crash 402 return ret; 403 } | |
| Title | drm/amd/display: Add null check for set_output_gamma in dcn30_set_output_transfer_func | |
| References | 
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Status: PUBLISHED
Assigner: Linux
Published: 2024-10-21T11:53:50.178Z
Updated: 2025-11-03T22:21:20.641Z
Reserved: 2024-09-30T16:00:12.950Z
Link: CVE-2024-47720
Updated: 2024-10-21T13:02:10.851Z
Status : Modified
Published: 2024-10-21T12:15:08.240
Modified: 2025-11-03T23:16:19.380
Link: CVE-2024-47720