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/microblaze/boot/Makefile | 35 +++++++++++++++++++++++++++++++++++ 1 file changed, 35 insertions(+) create mode 100644 arch/microblaze/boot/Makefile (limited to 'arch/microblaze/boot/Makefile') diff --git a/arch/microblaze/boot/Makefile b/arch/microblaze/boot/Makefile new file mode 100644 index 000000000..2b42c370d --- /dev/null +++ b/arch/microblaze/boot/Makefile @@ -0,0 +1,35 @@ +# SPDX-License-Identifier: GPL-2.0 +# +# arch/microblaze/boot/Makefile +# + +targets := linux.bin linux.bin.gz linux.bin.ub simpleImage.* + +OBJCOPYFLAGS := -R .note -R .comment -R .note.gnu.build-id -O binary + +$(obj)/linux.bin: vmlinux FORCE + $(call if_changed,objcopy) + +$(obj)/linux.bin.ub: $(obj)/linux.bin FORCE + $(call if_changed,uimage) + +$(obj)/linux.bin.gz: $(obj)/linux.bin FORCE + $(call if_changed,gzip) + +quiet_cmd_strip = STRIP $< $@$2 + cmd_strip = $(STRIP) -K microblaze_start -K _end -K __log_buf \ + -K _fdt_start $< -o $@$2 + +UIMAGE_LOADADDR = $(CONFIG_KERNEL_BASE_ADDR) + +$(obj)/simpleImage.$(DTB): vmlinux FORCE + $(call if_changed,objcopy) + +$(obj)/simpleImage.$(DTB).ub: $(obj)/simpleImage.$(DTB) FORCE + $(call if_changed,uimage) + +$(obj)/simpleImage.$(DTB).unstrip: vmlinux FORCE + $(call if_changed,copy) + +$(obj)/simpleImage.$(DTB).strip: vmlinux FORCE + $(call if_changed,strip) -- cgit v1.3.1