CVE-2024-47720

CVE-2024-47720 is a medium-severity vulnerability in Linux Linux Kernel with a CVSS 3.x base score of 5.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-476.

Key facts

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 }

Frequently asked questions

What is CVE-2024-47720?
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 }
How severe is CVE-2024-47720?
CVE-2024-47720 has a CVSS 3.x base score of 5.5, rated medium severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2024-47720 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (12th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2024-47720?
CVE-2024-47720 affects Linux Linux Kernel. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2024-47720?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2024-47720 have an EU (EUVD) identifier?
Yes. CVE-2024-47720 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2024-42639.
When was CVE-2024-47720 published?
CVE-2024-47720 was published on 2024-10-21 and last updated on 2026-06-17.

References

Affected products (1)

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