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, 51 insertions, 0 deletions

diff --git a/drivers/s390/char/Makefile b/drivers/s390/char/Makefile
new file mode 100644
index 000000000..126a87c3c
--- /dev/null
+++ b/drivers/s390/char/Makefile
@@ -0,0 +1,51 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# S/390 character devices
+#
+
+ifdef CONFIG_FUNCTION_TRACER
+# Do not trace early setup code
+CFLAGS_REMOVE_sclp_early_core.o	= $(CC_FLAGS_FTRACE)
+endif
+
+GCOV_PROFILE_sclp_early_core.o		:= n
+KCOV_INSTRUMENT_sclp_early_core.o	:= n
+UBSAN_SANITIZE_sclp_early_core.o	:= n
+KASAN_SANITIZE_sclp_early_core.o	:= n
+
+CFLAGS_sclp_early_core.o		+= -D__NO_FORTIFY
+
+CFLAGS_REMOVE_sclp_early_core.o	+= $(CC_FLAGS_EXPOLINE)
+
+obj-y += ctrlchar.o keyboard.o defkeymap.o sclp.o sclp_rw.o sclp_quiesce.o \
+	 sclp_cmd.o sclp_config.o sclp_cpi_sys.o sclp_ocf.o sclp_ctl.o \
+	 sclp_early.o sclp_early_core.o sclp_sd.o
+
+obj-$(CONFIG_MEMORY_HOTPLUG) += sclp_mem.o
+obj-$(CONFIG_TN3270) += raw3270.o con3270.o
+obj-$(CONFIG_TN3270_FS) += fs3270.o
+
+obj-$(CONFIG_TN3215) += con3215.o
+
+obj-$(CONFIG_SCLP_TTY) += sclp_tty.o
+obj-$(CONFIG_SCLP_CONSOLE) += sclp_con.o
+obj-$(CONFIG_SCLP_VT220_TTY) += sclp_vt220.o
+
+obj-$(CONFIG_PCI) += sclp_pci.o
+
+obj-$(subst m,y,$(CONFIG_AP)) += sclp_ap.o
+
+obj-$(CONFIG_VMLOGRDR) += vmlogrdr.o
+obj-$(CONFIG_VMCP) += vmcp.o
+
+tape-$(CONFIG_PROC_FS) += tape_proc.o
+tape_s390-objs := tape_3490.o tape_char.o tape_class.o tape_core.o tape_std.o $(tape-y)
+obj-$(CONFIG_S390_TAPE) += tape_s390.o
+obj-$(CONFIG_MONREADER) += monreader.o
+obj-$(CONFIG_MONWRITER) += monwriter.o
+obj-$(CONFIG_S390_VMUR) += vmur.o
+obj-$(CONFIG_CRASH_DUMP) += sclp_sdias.o zcore.o
+obj-$(CONFIG_S390_UV_UAPI) += uvdevice.o
+
+hmcdrv-objs := hmcdrv_mod.o hmcdrv_dev.o hmcdrv_ftp.o hmcdrv_cache.o diag_ftp.o sclp_ftp.o
+obj-$(CONFIG_HMC_DRV) += hmcdrv.o