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/mkcompile_h | 27 +++++++++++++++++++++++++++ 1 file changed, 27 insertions(+) create mode 100755 scripts/mkcompile_h (limited to 'scripts/mkcompile_h') diff --git a/scripts/mkcompile_h b/scripts/mkcompile_h new file mode 100755 index 000000000..2596f78e5 --- /dev/null +++ b/scripts/mkcompile_h @@ -0,0 +1,27 @@ +#!/bin/sh +# SPDX-License-Identifier: GPL-2.0 + +UTS_MACHINE=$1 +CC_VERSION="$2" +LD=$3 + +if test -z "$KBUILD_BUILD_USER"; then + LINUX_COMPILE_BY=$(whoami | sed 's/\\/\\\\/') +else + LINUX_COMPILE_BY=$KBUILD_BUILD_USER +fi +if test -z "$KBUILD_BUILD_HOST"; then + LINUX_COMPILE_HOST=`uname -n` +else + LINUX_COMPILE_HOST=$KBUILD_BUILD_HOST +fi + +LD_VERSION=$(LC_ALL=C $LD -v | head -n1 | + sed -e 's/(compatible with [^)]*)//' -e 's/[[:space:]]*$//') + +cat <