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 --- usr/Makefile | 85 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 85 insertions(+) create mode 100644 usr/Makefile (limited to 'usr/Makefile') diff --git a/usr/Makefile b/usr/Makefile new file mode 100644 index 000000000..e8f42478a --- /dev/null +++ b/usr/Makefile @@ -0,0 +1,85 @@ +# SPDX-License-Identifier: GPL-2.0 +# +# kbuild file for usr/ - including initramfs image +# + +compress-y := copy +compress-$(CONFIG_INITRAMFS_COMPRESSION_GZIP) := gzip +compress-$(CONFIG_INITRAMFS_COMPRESSION_BZIP2) := bzip2 +compress-$(CONFIG_INITRAMFS_COMPRESSION_LZMA) := lzma +compress-$(CONFIG_INITRAMFS_COMPRESSION_XZ) := xzmisc +compress-$(CONFIG_INITRAMFS_COMPRESSION_LZO) := lzo +compress-$(CONFIG_INITRAMFS_COMPRESSION_LZ4) := lz4 +compress-$(CONFIG_INITRAMFS_COMPRESSION_ZSTD) := zstd + +obj-$(CONFIG_BLK_DEV_INITRD) := initramfs_data.o + +$(obj)/initramfs_data.o: $(obj)/initramfs_inc_data + +hostprogs := gen_init_cpio + +ramfs-input := $(CONFIG_INITRAMFS_SOURCE) +cpio-data := + +# If CONFIG_INITRAMFS_SOURCE is empty, generate a small initramfs with the +# default contents. +ifeq ($(ramfs-input),) +ramfs-input := $(src)/default_cpio_list +endif + +ifeq ($(words $(ramfs-input)),1) + +# If CONFIG_INITRAMFS_SOURCE specifies a single file, and it is suffixed with +# .cpio, use it directly as an initramfs. +ifneq ($(filter %.cpio,$(ramfs-input)),) +cpio-data := $(ramfs-input) +endif + +# If CONFIG_INITRAMFS_SOURCE specifies a single file, and it is suffixed with +# .cpio.*, use it directly as an initramfs, and avoid double compression. +ifeq ($(words $(subst .cpio.,$(space),$(ramfs-input))),2) +cpio-data := $(ramfs-input) +compress-y := copy +endif + +endif + +# For other cases, generate the initramfs cpio archive based on the contents +# specified by CONFIG_INITRAMFS_SOURCE. +ifeq ($(cpio-data),) + +cpio-data := $(obj)/initramfs_data.cpio + +# .initramfs_data.cpio.d is used to identify all files included +# in initramfs and to detect if any files are added/removed. +# Removed files are identified by directory timestamp being updated +# The dependency list is generated by gen_initramfs.sh -l +-include $(obj)/.initramfs_data.cpio.d + +# do not try to update files included in initramfs +$(deps_initramfs): ; + +quiet_cmd_initfs = GEN $@ + cmd_initfs = \ + $(CONFIG_SHELL) $< -o $@ -l $(obj)/.initramfs_data.cpio.d \ + $(addprefix -u , $(CONFIG_INITRAMFS_ROOT_UID)) \ + $(addprefix -g , $(CONFIG_INITRAMFS_ROOT_GID)) \ + $(if $(KBUILD_BUILD_TIMESTAMP), -d "$(KBUILD_BUILD_TIMESTAMP)") \ + $(ramfs-input) + +# We rebuild initramfs_data.cpio if: +# 1) Any included file is newer than initramfs_data.cpio +# 2) There are changes in which files are included (added or deleted) +# 3) If gen_init_cpio are newer than initramfs_data.cpio +# 4) Arguments to gen_initramfs.sh changes +$(obj)/initramfs_data.cpio: $(src)/gen_initramfs.sh $(obj)/gen_init_cpio $(deps_initramfs) FORCE + $(call if_changed,initfs) + +endif + +$(obj)/initramfs_inc_data: $(cpio-data) FORCE + $(call if_changed,$(compress-y)) + +targets += initramfs_data.cpio initramfs_inc_data + +subdir-$(CONFIG_UAPI_HEADER_TEST) += include -- cgit v1.3.1