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, 44 insertions, 0 deletions

diff --git a/security/selinux/Makefile b/security/selinux/Makefile
new file mode 100644
index 000000000..72d3baf79
--- /dev/null
+++ b/security/selinux/Makefile
@@ -0,0 +1,44 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for building the SELinux module as part of the kernel tree.
+#
+
+# NOTE: There are a number of improvements that can be made to this Makefile
+# once the kernel requires make v4.3 or greater; the most important feature
+# lacking in older versions of make is support for grouped targets.  These
+# improvements are noted inline in the Makefile below ...
+
+obj-$(CONFIG_SECURITY_SELINUX) := selinux.o
+
+ccflags-y := -I$(srctree)/security/selinux -I$(srctree)/security/selinux/include
+
+ccflags-$(CONFIG_SECURITY_SELINUX_DEBUG) += -DDEBUG
+
+selinux-y := avc.o hooks.o selinuxfs.o netlink.o nlmsgtab.o netif.o \
+	     netnode.o netport.o status.o initcalls.o \
+	     ss/ebitmap.o ss/hashtab.o ss/symtab.o ss/sidtab.o ss/avtab.o \
+	     ss/policydb.o ss/services.o ss/conditional.o ss/mls.o ss/context.o
+
+selinux-$(CONFIG_SECURITY_NETWORK_XFRM) += xfrm.o
+selinux-$(CONFIG_NETLABEL) += netlabel.o
+selinux-$(CONFIG_SECURITY_INFINIBAND) += ibpkey.o
+selinux-$(CONFIG_IMA) += ima.o
+
+genhdrs := flask.h av_permissions.h
+
+# see the note above, replace the dependency rule with the one below:
+#  $(addprefix $(obj)/,$(selinux-y)): $(addprefix $(obj)/,$(genhdrs))
+$(addprefix $(obj)/,$(selinux-y)): $(obj)/flask.h
+
+quiet_cmd_genhdrs = GEN     $(addprefix $(obj)/,$(genhdrs))
+      cmd_genhdrs = $< $(addprefix $(obj)/,$(genhdrs))
+
+targets += $(genhdrs)
+
+# see the note above, replace the 'flask.h' rule with the line below:
+#  $(addprefix $(obj)/,$(genhdrs)) &: $(obj)/genheaders FORCE
+$(obj)/flask.h: $(obj)/genheaders FORCE
+	$(call if_changed,genhdrs)
+
+hostprogs := genheaders
+HOST_EXTRACFLAGS += -I$(srctree)/security/selinux/include