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, 29 insertions, 0 deletions

diff --git a/drivers/net/dsa/Makefile b/drivers/net/dsa/Makefile
new file mode 100644
index 000000000..d2975badf
--- /dev/null
+++ b/drivers/net/dsa/Makefile
@@ -0,0 +1,29 @@
+# SPDX-License-Identifier: GPL-2.0
+obj-$(CONFIG_NET_DSA_BCM_SF2)	+= bcm-sf2.o
+bcm-sf2-objs			:= bcm_sf2.o bcm_sf2_cfp.o
+obj-$(CONFIG_NET_DSA_LOOP)	+= dsa_loop.o
+obj-$(CONFIG_NET_DSA_KS8995) 	+= ks8995.o
+obj-$(CONFIG_NET_DSA_MT7530)	+= mt7530.o
+obj-$(CONFIG_NET_DSA_MT7530_MDIO) += mt7530-mdio.o
+obj-$(CONFIG_NET_DSA_MT7530_MMIO) += mt7530-mmio.o
+obj-$(CONFIG_NET_DSA_MV88E6060) += mv88e6060.o
+obj-$(CONFIG_NET_DSA_RZN1_A5PSW) += rzn1_a5psw.o
+obj-$(CONFIG_NET_DSA_SMSC_LAN9303) += lan9303-core.o
+obj-$(CONFIG_NET_DSA_SMSC_LAN9303_I2C) += lan9303_i2c.o
+obj-$(CONFIG_NET_DSA_SMSC_LAN9303_MDIO) += lan9303_mdio.o
+obj-$(CONFIG_NET_DSA_VITESSE_VSC73XX) += vitesse-vsc73xx-core.o
+obj-$(CONFIG_NET_DSA_VITESSE_VSC73XX_PLATFORM) += vitesse-vsc73xx-platform.o
+obj-$(CONFIG_NET_DSA_VITESSE_VSC73XX_SPI) += vitesse-vsc73xx-spi.o
+obj-$(CONFIG_NET_DSA_YT921X) += yt921x.o
+obj-y				+= b53/
+obj-y				+= hirschmann/
+obj-y				+= lantiq/
+obj-y				+= microchip/
+obj-y				+= mv88e6xxx/
+obj-y				+= mxl862xx/
+obj-y				+= netc/
+obj-y				+= ocelot/
+obj-y				+= qca/
+obj-y				+= realtek/
+obj-y				+= sja1105/
+obj-y				+= xrs700x/