[PATCH 6.18 669/752] drm/amdkfd: Fix out-of-bounds write in kfd_event_page_set()

Sasha Levin
2026-02-28T17:58:04Z

From: Sunday Clement <Sunday.Clement@amd.com>

[ Upstream commit 8a70a26c9f34baea6c3199a9862ddaff4554a96d ]

The kfd_event_page_set() function writes KFD_SIGNAL_EVENT_LIMIT * 8
bytes via memset without checking the buffer size parameter. This allows
unprivileged userspace to trigger an out-of bounds kernel memory write
by passing a small buffer, leading to potential privilege
escalation.

Signed-off-by: Sunday Clement <Sunday.Clement@amd.com>
Reviewed-by: Alexander Deucher <Alexander.Deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/gpu/drm/amd/amdkfd/kfd_events.c | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_events.c b/drivers/gpu/drm/amd/amdkfd/kfd_events.c
index 82905f3e54ddd..261db87e86fe6 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_events.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_events.c
@@ -331,6 +331,12 @@ static int kfd_event_page_set(struct kfd_process *p, void *kernel_address,
if (p->signal_page)
return -EBUSY;

+ if (size < KFD_SIGNAL_EVENT_LIMIT * 8) {
+ pr_err("Event page size %llu is too small, need at least %lu bytes\n",
+ size, (unsigned long)(KFD_SIGNAL_EVENT_LIMIT * 8));
+ return -EINVAL;
+ }
+
page = kzalloc(sizeof(*page), GFP_KERNEL);
if (!page)
return -ENOMEM;
--
2.51.0