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/arc/boot/Makefile | 38 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 38 insertions(+) create mode 100644 arch/arc/boot/Makefile (limited to 'arch/arc/boot/Makefile') diff --git a/arch/arc/boot/Makefile b/arch/arc/boot/Makefile new file mode 100644 index 000000000..5a8550124 --- /dev/null +++ b/arch/arc/boot/Makefile @@ -0,0 +1,38 @@ +# SPDX-License-Identifier: GPL-2.0 + +# uImage build relies on mkimage being available on your host for ARC target +# You will need to build u-boot for ARC, rename mkimage to arc-elf32-mkimage +# and make sure it's reachable from your PATH + +OBJCOPYFLAGS= -O binary -R .note -R .note.gnu.build-id -R .comment -S + +LINUX_START_TEXT = $$($(READELF) -h vmlinux | \ + grep "Entry point address" | grep -o 0x.*) + +UIMAGE_LOADADDR = $(CONFIG_LINUX_LINK_BASE) +UIMAGE_ENTRYADDR = $(LINUX_START_TEXT) + +targets += vmlinux.bin +targets += vmlinux.bin.gz +targets += vmlinux.bin.lzma +targets += uImage.bin +targets += uImage.gz +targets += uImage.lzma + +$(obj)/vmlinux.bin: vmlinux FORCE + $(call if_changed,objcopy) + +$(obj)/vmlinux.bin.gz: $(obj)/vmlinux.bin FORCE + $(call if_changed,gzip) + +$(obj)/vmlinux.bin.lzma: $(obj)/vmlinux.bin FORCE + $(call if_changed,lzma) + +$(obj)/uImage.bin: $(obj)/vmlinux.bin FORCE + $(call if_changed,uimage,none) + +$(obj)/uImage.gz: $(obj)/vmlinux.bin.gz FORCE + $(call if_changed,uimage,gzip) + +$(obj)/uImage.lzma: $(obj)/vmlinux.bin.lzma FORCE + $(call if_changed,uimage,lzma) -- cgit v1.3.1