queue-7.2/drm-panthor-fix-firmware-control-interface-bounds-checks.patch

From 6a47f9fd2d970674ed9dedc52fc7ab76fd015785 Mon Sep 17 00:00:00 2001
From: Osama Abdelkader <osama.abdelkader@gmail.com>
Date: Mon, 20 Jul 2026 15:44:35 +0200
Subject: drm/panthor: fix firmware control interface bounds checks

From: Osama Abdelkader <osama.abdelkader@gmail.com>

commit 6a47f9fd2d970674ed9dedc52fc7ab76fd015785 upstream.

panthor_init_cs_iface() and panthor_init_csg_iface() validate firmware
control interface offsets with 32-bit arithmetic and the size of the host
wrapper structures. The offsets are derived from firmware-provided strides,
so the arithmetic can wrap before the bounds check, and the host wrapper
size is not the size of the firmware control interface being mapped.

Use 64-bit arithmetic for the computed offsets and validate against the
actual firmware control interface structure sizes with subtraction-based
bounds checks. Also validate that the shared section is large enough for
the global control interface before using it.

Fixes: 2718d91816ee ("drm/panthor: Add the FW logical block")
Cc: stable@vger.kernel.org
Signed-off-by: Osama Abdelkader <osama.abdelkader@gmail.com>
Reviewed-by: Steven Price <steven.price@arm.com>
Reviewed-by: Liviu Dudau <liviu.dudau@arm.com>
Link: https://patch.msgid.link/20260720134435.13377-1-osama.abdelkader@gmail.com
Signed-off-by: Steven Price <steven.price@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/gpu/drm/panthor/panthor_fw.c |   19 +++++++++++++------
 1 file changed, 13 insertions(+), 6 deletions(-)

--- a/drivers/gpu/drm/panthor/panthor_fw.c
+++ b/drivers/gpu/drm/panthor/panthor_fw.c
@@ -895,14 +895,15 @@ static int panthor_init_cs_iface(struct
 	struct panthor_fw_csg_iface *csg_iface = panthor_fw_get_csg_iface(ptdev, csg_idx);
 	struct panthor_fw_cs_iface *cs_iface = &ptdev->fw->iface.streams[csg_idx][cs_idx];
 	u64 shared_section_sz = panthor_kernel_bo_size(ptdev->fw->shared_section->mem);
-	u32 iface_offset = CSF_GROUP_CONTROL_OFFSET +
-			   (csg_idx * glb_iface->control->group_stride) +
+	u64 iface_offset = CSF_GROUP_CONTROL_OFFSET +
+			   ((u64)csg_idx * glb_iface->control->group_stride) +
 			   CSF_STREAM_CONTROL_OFFSET +
-			   (cs_idx * csg_iface->control->stream_stride);
+			   ((u64)cs_idx * csg_iface->control->stream_stride);
 	struct panthor_fw_cs_iface *first_cs_iface =
 		panthor_fw_get_cs_iface(ptdev, 0, 0);
 
-	if (iface_offset + sizeof(*cs_iface) >= shared_section_sz)
+	if (iface_offset > shared_section_sz ||
+	    sizeof(*cs_iface->control) > shared_section_sz - iface_offset)
 		return -EINVAL;
 
 	spin_lock_init(&cs_iface->lock);
@@ -952,10 +953,12 @@ static int panthor_init_csg_iface(struct
 	struct panthor_fw_global_iface *glb_iface = panthor_fw_get_glb_iface(ptdev);
 	struct panthor_fw_csg_iface *csg_iface = &ptdev->fw->iface.groups[csg_idx];
 	u64 shared_section_sz = panthor_kernel_bo_size(ptdev->fw->shared_section->mem);
-	u32 iface_offset = CSF_GROUP_CONTROL_OFFSET + (csg_idx * glb_iface->control->group_stride);
+	u64 iface_offset = CSF_GROUP_CONTROL_OFFSET +
+			   ((u64)csg_idx * glb_iface->control->group_stride);
 	unsigned int i;
 
-	if (iface_offset + sizeof(*csg_iface) >= shared_section_sz)
+	if (iface_offset > shared_section_sz ||
+	    sizeof(*csg_iface->control) > shared_section_sz - iface_offset)
 		return -EINVAL;
 
 	spin_lock_init(&csg_iface->lock);
@@ -1007,11 +1010,15 @@ static u32 panthor_get_instr_features(st
 static int panthor_fw_init_ifaces(struct panthor_device *ptdev)
 {
 	struct panthor_fw_global_iface *glb_iface = &ptdev->fw->iface.global;
+	u64 shared_section_sz = panthor_kernel_bo_size(ptdev->fw->shared_section->mem);
 	unsigned int i;
 
 	if (!ptdev->fw->shared_section->mem->kmap)
 		return -EINVAL;
 
+	if (sizeof(*glb_iface->control) > shared_section_sz)
+		return -EINVAL;
+
 	spin_lock_init(&glb_iface->lock);
 	glb_iface->control = ptdev->fw->shared_section->mem->kmap;