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/media/media-dev-allocator.h | 63 +++++++++++++++++++++++++++++++++++++ 1 file changed, 63 insertions(+) create mode 100644 include/media/media-dev-allocator.h (limited to 'include/media/media-dev-allocator.h') diff --git a/include/media/media-dev-allocator.h b/include/media/media-dev-allocator.h new file mode 100644 index 000000000..2ab54d426 --- /dev/null +++ b/include/media/media-dev-allocator.h @@ -0,0 +1,63 @@ +/* SPDX-License-Identifier: GPL-2.0+ */ +/* + * media-dev-allocator.h - Media Controller Device Allocator API + * + * Copyright (c) 2019 Shuah Khan + * + * Credits: Suggested by Laurent Pinchart + */ + +/* + * This file adds a global ref-counted Media Controller Device Instance API. + * A system wide global media device list is managed and each media device + * includes a kref count. The last put on the media device releases the media + * device instance. + */ + +#ifndef _MEDIA_DEV_ALLOCATOR_H +#define _MEDIA_DEV_ALLOCATOR_H + +struct usb_device; + +#if defined(CONFIG_MEDIA_CONTROLLER) && IS_ENABLED(CONFIG_USB) +/** + * media_device_usb_allocate() - Allocate and return struct &media device + * + * @udev: struct &usb_device pointer + * @module_name: should be filled with %KBUILD_MODNAME + * @owner: struct module pointer %THIS_MODULE for the driver. + * %THIS_MODULE is null for a built-in driver. + * It is safe even when %THIS_MODULE is null. + * + * This interface should be called to allocate a Media Device when multiple + * drivers share usb_device and the media device. This interface allocates + * &media_device structure and calls media_device_usb_init() to initialize + * it. + * + */ +struct media_device *media_device_usb_allocate(struct usb_device *udev, + const char *module_name, + struct module *owner); +/** + * media_device_delete() - Release media device. Calls kref_put(). + * + * @mdev: struct &media_device pointer + * @module_name: should be filled with %KBUILD_MODNAME + * @owner: struct module pointer %THIS_MODULE for the driver. + * %THIS_MODULE is null for a built-in driver. + * It is safe even when %THIS_MODULE is null. + * + * This interface should be called to put Media Device Instance kref. + */ +void media_device_delete(struct media_device *mdev, const char *module_name, + struct module *owner); +#else +static inline struct media_device *media_device_usb_allocate( + struct usb_device *udev, const char *module_name, + struct module *owner) + { return NULL; } +static inline void media_device_delete( + struct media_device *mdev, const char *module_name, + struct module *owner) { } +#endif /* CONFIG_MEDIA_CONTROLLER && CONFIG_USB */ +#endif /* _MEDIA_DEV_ALLOCATOR_H */ -- cgit v1.3.1