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, 48 insertions, 0 deletions

diff --git a/net/dsa/Makefile b/net/dsa/Makefile
new file mode 100644
index 000000000..b8c2667cd
--- /dev/null
+++ b/net/dsa/Makefile
@@ -0,0 +1,48 @@
+# SPDX-License-Identifier: GPL-2.0
+
+# the stubs are built-in whenever DSA is built-in or module
+ifdef CONFIG_NET_DSA
+obj-y := stubs.o
+endif
+
+# the core
+obj-$(CONFIG_NET_DSA) += dsa_core.o
+dsa_core-y += \
+	conduit.o \
+	devlink.o \
+	dsa.o \
+	netlink.o \
+	port.o \
+	switch.o \
+	tag.o \
+	tag_8021q.o \
+	trace.o \
+	user.o
+
+# tagging formats
+obj-$(CONFIG_NET_DSA_TAG_AR9331) += tag_ar9331.o
+obj-$(CONFIG_NET_DSA_TAG_BRCM_COMMON) += tag_brcm.o
+obj-$(CONFIG_NET_DSA_TAG_DSA_COMMON) += tag_dsa.o
+obj-$(CONFIG_NET_DSA_TAG_GSWIP) += tag_gswip.o
+obj-$(CONFIG_NET_DSA_TAG_HELLCREEK) += tag_hellcreek.o
+obj-$(CONFIG_NET_DSA_TAG_KSZ) += tag_ksz.o
+obj-$(CONFIG_NET_DSA_TAG_LAN9303) += tag_lan9303.o
+obj-$(CONFIG_NET_DSA_TAG_MTK) += tag_mtk.o
+obj-$(CONFIG_NET_DSA_TAG_MXL_862XX) += tag_mxl862xx.o
+obj-$(CONFIG_NET_DSA_TAG_MXL_GSW1XX) += tag_mxl-gsw1xx.o
+obj-$(CONFIG_NET_DSA_TAG_NETC) += tag_netc.o
+obj-$(CONFIG_NET_DSA_TAG_NONE) += tag_none.o
+obj-$(CONFIG_NET_DSA_TAG_OCELOT) += tag_ocelot.o
+obj-$(CONFIG_NET_DSA_TAG_OCELOT_8021Q) += tag_ocelot_8021q.o
+obj-$(CONFIG_NET_DSA_TAG_QCA) += tag_qca.o
+obj-$(CONFIG_NET_DSA_TAG_RTL4_A) += tag_rtl4_a.o
+obj-$(CONFIG_NET_DSA_TAG_RTL8_4) += tag_rtl8_4.o
+obj-$(CONFIG_NET_DSA_TAG_RZN1_A5PSW) += tag_rzn1_a5psw.o
+obj-$(CONFIG_NET_DSA_TAG_SJA1105) += tag_sja1105.o
+obj-$(CONFIG_NET_DSA_TAG_TRAILER) += tag_trailer.o
+obj-$(CONFIG_NET_DSA_TAG_VSC73XX_8021Q) += tag_vsc73xx_8021q.o
+obj-$(CONFIG_NET_DSA_TAG_XRS700X) += tag_xrs700x.o
+obj-$(CONFIG_NET_DSA_TAG_YT921X) += tag_yt921x.o
+
+# for tracing framework to find trace.h
+CFLAGS_trace.o := -I$(src)