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 --- arch/xtensa/boot/Makefile | 53 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 53 insertions(+) create mode 100644 arch/xtensa/boot/Makefile (limited to 'arch/xtensa/boot/Makefile') diff --git a/arch/xtensa/boot/Makefile b/arch/xtensa/boot/Makefile new file mode 100644 index 000000000..d8b0fadf4 --- /dev/null +++ b/arch/xtensa/boot/Makefile @@ -0,0 +1,53 @@ +# +# arch/xtensa/boot/Makefile +# +# This file is subject to the terms and conditions of the GNU General Public +# License. See the file "COPYING" in the main directory of this archive +# for more details. +# +# + + +# KBUILD_CFLAGS used when building rest of boot (takes effect recursively) +KBUILD_CFLAGS += -fno-builtin + +subdir-y := lib +targets += vmlinux.bin vmlinux.bin.gz +targets += uImage xipImage + +# Subdirs for the boot loader(s) + +boot-$(CONFIG_XTENSA_PLATFORM_ISS) += Image +boot-$(CONFIG_XTENSA_PLATFORM_XT2000) += Image zImage uImage +boot-$(CONFIG_XTENSA_PLATFORM_XTFPGA) += Image zImage uImage + +all: $(boot-y) +Image: boot-elf +zImage: boot-redboot +uImage: $(obj)/uImage +xipImage: $(obj)/xipImage + +boot-elf boot-redboot: $(addprefix $(obj)/,$(subdir-y)) + $(Q)$(MAKE) $(build)=$(obj)/$@ $(MAKECMDGOALS) + +OBJCOPYFLAGS = --strip-all -R .comment -R .notes -O binary + +$(obj)/vmlinux.bin: vmlinux FORCE + $(call if_changed,objcopy) + +$(obj)/vmlinux.bin.gz: $(obj)/vmlinux.bin FORCE + $(call if_changed,gzip) + +boot-elf: $(obj)/vmlinux.bin +boot-redboot: $(obj)/vmlinux.bin.gz + +UIMAGE_LOADADDR = $(CONFIG_KERNEL_LOAD_ADDRESS) +UIMAGE_COMPRESSION = gzip + +$(obj)/uImage: $(obj)/vmlinux.bin.gz FORCE + $(call if_changed,uimage) + $(Q)$(kecho) ' Kernel: $@ is ready' + +$(obj)/xipImage: vmlinux FORCE + $(call if_changed,objcopy) + $(Q)$(kecho) ' Kernel: $@ is ready' -- cgit v1.3.1