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/drm_accel.h | 85 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 85 insertions(+) create mode 100644 include/drm/drm_accel.h (limited to 'include/drm/drm_accel.h') diff --git a/include/drm/drm_accel.h b/include/drm/drm_accel.h new file mode 100644 index 000000000..20a665ec6 --- /dev/null +++ b/include/drm/drm_accel.h @@ -0,0 +1,85 @@ +/* SPDX-License-Identifier: GPL-2.0 + * + * Copyright 2022 HabanaLabs, Ltd. + * All Rights Reserved. + * + */ + +#ifndef DRM_ACCEL_H_ +#define DRM_ACCEL_H_ + +#include + +#define ACCEL_MAJOR 261 +#define ACCEL_MAX_MINORS 256 + +/** + * DRM_ACCEL_FOPS - Default drm accelerators file operations + * + * This macro provides a shorthand for setting the accelerator file ops in the + * &file_operations structure. If all you need are the default ops, use + * DEFINE_DRM_ACCEL_FOPS instead. + */ +#define DRM_ACCEL_FOPS \ + .open = accel_open,\ + .release = drm_release,\ + .unlocked_ioctl = drm_ioctl,\ + .compat_ioctl = drm_compat_ioctl,\ + .poll = drm_poll,\ + .read = drm_read,\ + .llseek = noop_llseek, \ + .mmap = drm_gem_mmap, \ + .fop_flags = FOP_UNSIGNED_OFFSET + +/** + * DEFINE_DRM_ACCEL_FOPS() - macro to generate file operations for accelerators drivers + * @name: name for the generated structure + * + * This macro autogenerates a suitable &struct file_operations for accelerators based + * drivers, which can be assigned to &drm_driver.fops. Note that this structure + * cannot be shared between drivers, because it contains a reference to the + * current module using THIS_MODULE. + * + * Note that the declaration is already marked as static - if you need a + * non-static version of this you're probably doing it wrong and will break the + * THIS_MODULE reference by accident. + */ +#define DEFINE_DRM_ACCEL_FOPS(name) \ + static const struct file_operations name = {\ + .owner = THIS_MODULE,\ + DRM_ACCEL_FOPS,\ + } + +#if IS_ENABLED(CONFIG_DRM_ACCEL) + +extern struct xarray accel_minors_xa; + +void accel_core_exit(void); +int accel_core_init(void); +void accel_set_device_instance_params(struct device *kdev, int index); +int accel_open(struct inode *inode, struct file *filp); +void accel_debugfs_register(struct drm_device *dev); + +#else + +static inline void accel_core_exit(void) +{ +} + +static inline int __init accel_core_init(void) +{ + /* Return 0 to allow drm_core_init to complete successfully */ + return 0; +} + +static inline void accel_set_device_instance_params(struct device *kdev, int index) +{ +} + +static inline void accel_debugfs_register(struct drm_device *dev) +{ +} + +#endif /* IS_ENABLED(CONFIG_DRM_ACCEL) */ + +#endif /* DRM_ACCEL_H_ */ -- cgit v1.3.1