From: Zack Rusin zack.rusin@broadcom.com

mainline inclusion from mainline-v6.9-rc7 commit a37ef7613c00f2d72c8fc08bd83fb6cc76926c8c category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I9UNUO CVE: CVE-2024-36960

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...

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Correctly set the length of the drm_event to the size of the structure that's actually used.

The length of the drm_event was set to the parent structure instead of to the drm_vmw_event_fence which is supposed to be read. drm_read uses the length parameter to copy the event to the user space thus resuling in oob reads.

Signed-off-by: Zack Rusin zack.rusin@broadcom.com Fixes: 8b7de6aa8468 ("vmwgfx: Rework fence event action") Reported-by: zdi-disclosures@trendmicro.com # ZDI-CAN-23566 Cc: David Airlie airlied@gmail.com CC: Daniel Vetter daniel@ffwll.ch Cc: Zack Rusin zack.rusin@broadcom.com Cc: Broadcom internal kernel review list bcm-kernel-feedback-list@broadcom.com Cc: dri-devel@lists.freedesktop.org Cc: linux-kernel@vger.kernel.org Cc: stable@vger.kernel.org # v3.4+ Reviewed-by: Maaz Mombasawala maaz.mombasawala@broadcom.com Reviewed-by: Martin Krastev martin.krastev@broadcom.com Link: https://patchwork.freedesktop.org/patch/msgid/20240425192748.1761522-1-zack.... Signed-off-by: Cheng Yu serein.chengyu@huawei.com --- drivers/gpu/drm/vmwgfx/vmwgfx_fence.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_fence.c b/drivers/gpu/drm/vmwgfx/vmwgfx_fence.c index 8bc41ec97d71..6bacdb7583df 100644 --- a/drivers/gpu/drm/vmwgfx/vmwgfx_fence.c +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_fence.c @@ -1066,7 +1066,7 @@ static int vmw_event_fence_action_create(struct drm_file *file_priv, }

event->event.base.type = DRM_VMW_EVENT_FENCE_SIGNALED; - event->event.base.length = sizeof(*event); + event->event.base.length = sizeof(event->event); event->event.user_data = user_data;

ret = drm_event_reserve_init(dev, file_priv, &event->base, &event->event.base);