[PATCH] drm/amd/display:fix a Null pointer dereference vulnerability
jackysliu
1972843537 at qq.com
Thu Jul 3 03:39:28 UTC 2025
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
Signed-off-by: jackysliu <Security at tencent.com>
---
drivers/gpu/drm/amd/display/dc/core/dc.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/drivers/gpu/drm/amd/display/dc/core/dc.c b/drivers/gpu/drm/amd/display/dc/core/dc.c
index 56d011a1323c..3bda0593f66f 100644
--- a/drivers/gpu/drm/amd/display/dc/core/dc.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc.c
@@ -934,6 +934,11 @@ static void dc_destruct(struct dc *dc)
if (dc->link_srv)
link_destroy_link_service(&dc->link_srv);
+ if (!dc->ctx) {
+ dm_error("%s: called with NULL ctx\n", __func__);
+ goto skip_ctx_cleanup;
+ }
+
if (dc->ctx->gpio_service)
dal_gpio_service_destroy(&dc->ctx->gpio_service);
@@ -946,6 +951,7 @@ static void dc_destruct(struct dc *dc)
kfree(dc->ctx);
dc->ctx = NULL;
+skip_ctx_cleanup:
kfree(dc->bw_vbios);
dc->bw_vbios = NULL;
--
2.43.5
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