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 --- scripts/makelst | 32 ++++++++++++++++++++++++++++++++ 1 file changed, 32 insertions(+) create mode 100755 scripts/makelst (limited to 'scripts/makelst') diff --git a/scripts/makelst b/scripts/makelst new file mode 100755 index 000000000..e432af073 --- /dev/null +++ b/scripts/makelst @@ -0,0 +1,32 @@ +#!/bin/sh +# SPDX-License-Identifier: GPL-2.0 +# A script to dump mixed source code & assembly +# with correct relocations from System.map +# Requires the following lines in makefile: +#%.lst: %.c +# $(CC) $(c_flags) -g -c -o $*.o $< && +# $(srctree)/scripts/makelst $*.o System.map $(OBJDUMP) > $@ +# +# Copyright (C) 2000 IBM Corporation +# Author(s): DJ Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com) +# William Stearns +# + +# awk style field access +field() { + shift $1 ; echo $1 +} + +t1=`$3 --syms $1 | grep .text | grep -m1 " F "` +if [ -n "$t1" ]; then + t2=`field 6 $t1` + if [ ! -r $2 ]; then + echo "No System.map" >&2 + else + t3=`grep $t2 $2` + t4=`field 1 $t3` + t5=`field 1 $t1` + t6=`printf "%lu" $((0x$t4 - 0x$t5))` + fi +fi +$3 -r --source --adjust-vma=${t6:-0} $1 -- cgit v1.3.1