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, 21 insertions, 0 deletions

diff --git a/drivers/phy/ralink/Kconfig b/drivers/phy/ralink/Kconfig
new file mode 100644
index 000000000..c2373b30b
--- /dev/null
+++ b/drivers/phy/ralink/Kconfig
@@ -0,0 +1,21 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# PHY drivers for Ralink platforms.
+#
+config PHY_MT7621_PCI
+	tristate "MediaTek MT7621 PCI PHY Driver"
+	depends on (RALINK && OF) || COMPILE_TEST
+	select GENERIC_PHY
+	select REGMAP_MMIO
+	help
+	  Say 'Y' here to add support for MediaTek MT7621 PCI PHY driver,
+
+config PHY_RALINK_USB
+	tristate "Ralink USB PHY driver"
+	depends on RALINK || COMPILE_TEST
+	depends on HAS_IOMEM
+	select GENERIC_PHY
+	select MFD_SYSCON
+	help
+	  This option enables support for the Ralink USB PHY found inside
+	  RT3352, MT7620, MT7628 and MT7688.