openrisc: fix arbitrary kernel memory access via or1k_atomic syscallgrafted

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 <ali@iusegentoo.com>
Signed-off-by: Stafford Horne <shorne@gmail.com>

1 files changed, 42 insertions, 0 deletions

diff --git a/scripts/kconfig/qconf-cfg.sh b/scripts/kconfig/qconf-cfg.sh
new file mode 100755
index 000000000..bb2df6636
--- /dev/null
+++ b/scripts/kconfig/qconf-cfg.sh
@@ -0,0 +1,42 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+
+set -eu
+
+cflags=$1
+libs=$2
+bin=$3
+
+PKG5="Qt5Core Qt5Gui Qt5Widgets"
+PKG6="Qt6Core Qt6Gui Qt6Widgets"
+
+if [ -z "$(command -v ${HOSTPKG_CONFIG})" ]; then
+	echo >&2 "*"
+	echo >&2 "* 'make xconfig' requires '${HOSTPKG_CONFIG}'. Please install it."
+	echo >&2 "*"
+	exit 1
+fi
+
+if ${HOSTPKG_CONFIG} --exists $PKG6; then
+	${HOSTPKG_CONFIG} --cflags ${PKG6} > ${cflags}
+	# Qt6 requires C++17.
+	echo -std=c++17 >> ${cflags}
+	${HOSTPKG_CONFIG} --libs ${PKG6} > ${libs}
+	${HOSTPKG_CONFIG} --variable=libexecdir Qt6Core > ${bin}
+	exit 0
+fi
+
+if ${HOSTPKG_CONFIG} --exists $PKG5; then
+	${HOSTPKG_CONFIG} --cflags ${PKG5} > ${cflags}
+	${HOSTPKG_CONFIG} --libs ${PKG5} > ${libs}
+	${HOSTPKG_CONFIG} --variable=host_bins Qt5Core > ${bin}
+	exit 0
+fi
+
+echo >&2 "*"
+echo >&2 "* Could not find Qt6 or Qt5 via ${HOSTPKG_CONFIG}."
+echo >&2 "* Please install Qt6 or Qt5 and make sure it's in PKG_CONFIG_PATH"
+echo >&2 "* You need $PKG6 for Qt6"
+echo >&2 "* You need $PKG5 for Qt5"
+echo >&2 "*"
+exit 1