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 --- fs/hostfs/Makefile | 13 +++++++++++++ 1 file changed, 13 insertions(+) create mode 100644 fs/hostfs/Makefile (limited to 'fs/hostfs/Makefile') diff --git a/fs/hostfs/Makefile b/fs/hostfs/Makefile new file mode 100644 index 000000000..16be592e8 --- /dev/null +++ b/fs/hostfs/Makefile @@ -0,0 +1,13 @@ +# +# Copyright (C) 2000 Jeff Dike (jdike@karaya.com) +# Licensed under the GPL +# + +hostfs-objs := hostfs_kern.o + +hostfs-builtin-$(CONFIG_HOSTFS) += hostfs_user.o hostfs_user_exp.o + +obj-y := $(hostfs-builtin-y) $(hostfs-builtin-m) +obj-$(CONFIG_HOSTFS) += hostfs.o + +include $(srctree)/arch/um/scripts/Makefile.rules -- cgit v1.3.1