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drm/amd/display: fix a Null pointer dereference vulnerability

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[Why]
A null pointer dereference vulnerability exists in the AMD display driver's
(DC module) cleanup function dc_destruct().
When display control context (dc->ctx) construction fails
(due to memory allocation failure), this pointer remains NULL.
During subsequent error handling when dc_destruct() is called,
there's no NULL check before dereferencing the perf_trace member
(dc->ctx->perf_trace), causing a kernel null pointer dereference crash.

[How]
Check if dc->ctx is non-NULL before dereferencing.

Link: https://lore.kernel.org/r/tencent_54FF4252EDFB6533090A491A25EEF3EDBF06@qq.com
Co-developed-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
(Updated commit text and removed unnecessary error message)
Signed-off-by: Siyang Liu <Security@tencent.com>
Signed-off-by: Roman Li <roman.li@amd.com>
Reviewed-by: Alex Hung <alex.hung@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit 9dd8e2ba26)
Cc: stable@vger.kernel.org
This commit is contained in:
Siyang Liu 2025-07-04 11:16:22 +08:00 committed by Alex Deucher
parent 3477c1b097
commit 1bcf63a443
1 changed files with 10 additions and 9 deletions
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19
drivers/gpu/drm/amd/display/dc/core/dc.c
View File

@ -938,17 +938,18 @@ static void dc_destruct(struct dc *dc)
if (dc->link_srv)
link_destroy_link_service(&dc->link_srv);
if (dc->ctx->gpio_service)
dal_gpio_service_destroy(&dc->ctx->gpio_service);
if (dc->ctx) {
if (dc->ctx->gpio_service)
dal_gpio_service_destroy(&dc->ctx->gpio_service);
if (dc->ctx->created_bios)
dal_bios_parser_destroy(&dc->ctx->dc_bios);
if (dc->ctx->created_bios)
dal_bios_parser_destroy(&dc->ctx->dc_bios);
kfree(dc->ctx->logger);
dc_perf_trace_destroy(&dc->ctx->perf_trace);
kfree(dc->ctx->logger);
dc_perf_trace_destroy(&dc->ctx->perf_trace);
kfree(dc->ctx);
dc->ctx = NULL;
kfree(dc->ctx);
dc->ctx = NULL;
}
kfree(dc->bw_vbios);
dc->bw_vbios = NULL;