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 --- drivers/nvmem/internals.h | 61 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 61 insertions(+) create mode 100644 drivers/nvmem/internals.h (limited to 'drivers/nvmem/internals.h') diff --git a/drivers/nvmem/internals.h b/drivers/nvmem/internals.h new file mode 100644 index 000000000..f6d452b6a --- /dev/null +++ b/drivers/nvmem/internals.h @@ -0,0 +1,61 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#ifndef _LINUX_NVMEM_INTERNALS_H +#define _LINUX_NVMEM_INTERNALS_H + +#include +#include +#include + +struct nvmem_device { + struct module *owner; + struct device dev; + struct list_head node; + int stride; + int word_size; + int id; + struct kref refcnt; + size_t size; + bool read_only; + bool root_only; + int flags; + enum nvmem_type type; + struct bin_attribute eeprom; + struct device *base_dev; + struct list_head cells; + void (*fixup_dt_cell_info)(struct nvmem_device *nvmem, + struct nvmem_cell_info *cell); + const struct nvmem_keepout *keepout; + unsigned int nkeepout; + nvmem_reg_read_t reg_read; + nvmem_reg_write_t reg_write; + struct gpio_desc *wp_gpio; + struct nvmem_layout *layout; + void *priv; + bool sysfs_cells_populated; +}; + +int nvmem_add_cells_from_dt(struct nvmem_device *nvmem, struct device_node *np); + +#if IS_ENABLED(CONFIG_OF) +int nvmem_layout_bus_register(void); +void nvmem_layout_bus_unregister(void); +int nvmem_populate_layout(struct nvmem_device *nvmem); +void nvmem_destroy_layout(struct nvmem_device *nvmem); +#else /* CONFIG_OF */ +static inline int nvmem_layout_bus_register(void) +{ + return 0; +} + +static inline void nvmem_layout_bus_unregister(void) {} + +static inline int nvmem_populate_layout(struct nvmem_device *nvmem) +{ + return 0; +} + +static inline void nvmem_destroy_layout(struct nvmem_device *nvmem) { } +#endif /* CONFIG_OF */ + +#endif /* ifndef _LINUX_NVMEM_INTERNALS_H */ -- cgit v1.3.1