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/lib/Makefile | 15 +++++++++++++++ 1 file changed, 15 insertions(+) create mode 100644 arch/arc/lib/Makefile (limited to 'arch/arc/lib/Makefile') diff --git a/arch/arc/lib/Makefile b/arch/arc/lib/Makefile new file mode 100644 index 000000000..30158ae69 --- /dev/null +++ b/arch/arc/lib/Makefile @@ -0,0 +1,15 @@ +# SPDX-License-Identifier: GPL-2.0-only +# +# Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com) +# + +lib-y := strchr-700.o strcpy-700.o strlen.o memcmp.o + +lib-$(CONFIG_ISA_ARCOMPACT) += memcpy-700.o memset.o strcmp.o +lib-$(CONFIG_ISA_ARCV2) += memset-archs.o strcmp-archs.o + +ifdef CONFIG_ARC_USE_UNALIGNED_MEM_ACCESS +lib-$(CONFIG_ISA_ARCV2) +=memcpy-archs-unaligned.o +else +lib-$(CONFIG_ISA_ARCV2) +=memcpy-archs.o +endif -- cgit v1.3.1