From 78004e9a87f240df03e2f73120d291763c32e0a7 Mon Sep 17 00:00:00 2001 From: Ali Ahmet Memis Date: Fri, 21 Aug 2026 01:45:27 +0000 Subject: openrisc: fix arbitrary kernel memory access via or1k_atomic syscall sys_or1k_atomic() (syscall 244 in the "or1k" ABI) takes two user pointers, v1 and v2, and swaps the words they point to in hand-written assembly. l.lwz r29,0(r4) l.lwz r27,0(r5) l.sw 0(r4),r27 l.sw 0(r5),r29 The pointers are not checked with access_ok(). The four memory accesses also have no exception table entries. A caller passes a kernel address as either pointer, and the syscall reads from and writes to it directly. This gives an unprivileged process a kernel read/write primitive. It overwrites kernel data such as the sys_call_table, gaining code execution in kernel context. Check both pointers before entering the critical section. Add fixups for the four memory accesses so faults on valid but unmapped user addresses return -EFAULT. [shorne@gmail.com: fix comment style] Fixes: 9d02a4283e9c ("OpenRISC: Boot code") Cc: stable@vger.kernel.org Signed-off-by: Ali Ahmet Memis Signed-off-by: Stafford Horne --- include/drm/intel/intel-gtt.h | 41 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 41 insertions(+) create mode 100644 include/drm/intel/intel-gtt.h (limited to 'include/drm/intel/intel-gtt.h') diff --git a/include/drm/intel/intel-gtt.h b/include/drm/intel/intel-gtt.h new file mode 100644 index 000000000..f53bcff01 --- /dev/null +++ b/include/drm/intel/intel-gtt.h @@ -0,0 +1,41 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* Common header for intel-gtt.ko and i915.ko */ + +#ifndef _DRM_INTEL_GTT_H +#define _DRM_INTEL_GTT_H + +#include + +struct agp_bridge_data; +struct pci_dev; +struct sg_table; + +void intel_gmch_gtt_get(u64 *gtt_total, + phys_addr_t *mappable_base, + resource_size_t *mappable_end); + +int intel_gmch_probe(struct pci_dev *bridge_pdev, struct pci_dev *gpu_pdev, + struct agp_bridge_data *bridge); +void intel_gmch_remove(void); + +bool intel_gmch_enable_gtt(void); + +void intel_gmch_gtt_flush(void); +void intel_gmch_gtt_insert_page(dma_addr_t addr, + unsigned int pg, + unsigned int flags); +void intel_gmch_gtt_insert_sg_entries(struct sg_table *st, + unsigned int pg_start, + unsigned int flags); +void intel_gmch_gtt_clear_range(unsigned int first_entry, unsigned int num_entries); +dma_addr_t intel_gmch_gtt_read_entry(unsigned int pg, + bool *is_present, bool *is_local); + +/* Special gtt memory types */ +#define AGP_DCACHE_MEMORY 1 +#define AGP_PHYS_MEMORY 2 + +/* flag for GFDT type */ +#define AGP_USER_CACHED_MEMORY_GFDT (1 << 3) + +#endif -- cgit v1.3.1