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, 62 insertions, 0 deletions

diff --git a/lib/tests/Makefile b/lib/tests/Makefile
new file mode 100644
index 000000000..4ead57602
--- /dev/null
+++ b/lib/tests/Makefile
@@ -0,0 +1,62 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for tests of kernel library functions.
+
+# KUnit tests
+CFLAGS_bitfield_kunit.o := $(DISABLE_STRUCTLEAK_PLUGIN)
+obj-$(CONFIG_BASE64_KUNIT) += base64_kunit.o
+obj-$(CONFIG_BITOPS_KUNIT) += bitops_kunit.o
+obj-$(CONFIG_BITFIELD_KUNIT) += bitfield_kunit.o
+obj-$(CONFIG_BITS_TEST) += test_bits.o
+obj-$(CONFIG_SHDI3_KUNIT_TEST) += shdi3_kunit.o
+obj-$(CONFIG_BLACKHOLE_DEV_KUNIT_TEST) += blackhole_dev_kunit.o
+obj-$(CONFIG_CHECKSUM_KUNIT) += checksum_kunit.o
+obj-$(CONFIG_CMDLINE_KUNIT_TEST) += cmdline_kunit.o
+obj-$(CONFIG_CPUMASK_KUNIT_TEST) += cpumask_kunit.o
+obj-$(CONFIG_FFS_KUNIT_TEST) += ffs_kunit.o
+CFLAGS_fortify_kunit.o += $(call cc-disable-warning, unsequenced)
+CFLAGS_fortify_kunit.o += $(call cc-disable-warning, stringop-overread)
+CFLAGS_fortify_kunit.o += $(call cc-disable-warning, stringop-truncation)
+CFLAGS_fortify_kunit.o += $(DISABLE_STRUCTLEAK_PLUGIN)
+obj-$(CONFIG_FORTIFY_KUNIT_TEST) += fortify_kunit.o
+CFLAGS_test_fprobe.o += $(CC_FLAGS_FTRACE)
+obj-$(CONFIG_FPROBE_SANITY_TEST) += test_fprobe.o
+obj-$(CONFIG_GLOB_KUNIT_TEST) += glob_kunit.o
+obj-$(CONFIG_HASHTABLE_KUNIT_TEST) += hashtable_test.o
+obj-$(CONFIG_HASH_KUNIT_TEST) += test_hash.o
+obj-$(CONFIG_TEST_IOV_ITER) += kunit_iov_iter.o
+obj-$(CONFIG_IS_SIGNED_TYPE_KUNIT_TEST) += is_signed_type_kunit.o
+obj-$(CONFIG_KPROBES_SANITY_TEST) += test_kprobes.o
+obj-$(CONFIG_LIST_KUNIT_TEST) += list-test.o
+obj-$(CONFIG_LIST_PRIVATE_KUNIT_TEST) += list-private-test.o
+obj-$(CONFIG_KFIFO_KUNIT_TEST) += kfifo_kunit.o
+obj-$(CONFIG_TEST_LIST_SORT) += test_list_sort.o
+obj-$(CONFIG_LINEAR_RANGES_TEST) += test_linear_ranges.o
+obj-$(CONFIG_LIVEUPDATE_TEST) += liveupdate.o
+
+CFLAGS_longest_symbol_kunit.o += $(call cc-disable-warning, missing-prototypes)
+obj-$(CONFIG_LONGEST_SYM_KUNIT_TEST) += longest_symbol_kunit.o
+
+obj-$(CONFIG_MEMCPY_KUNIT_TEST) += memcpy_kunit.o
+obj-$(CONFIG_MIN_HEAP_KUNIT_TEST) += min_heap_kunit.o
+CFLAGS_overflow_kunit.o = $(call cc-disable-warning, tautological-constant-out-of-range-compare)
+obj-$(CONFIG_OVERFLOW_KUNIT_TEST) += overflow_kunit.o
+# GCC < 12.1 can miscompile errptr() test when branch profiling is enabled.
+CFLAGS_printf_kunit.o += -DDISABLE_BRANCH_PROFILING
+obj-$(CONFIG_PRINTF_KUNIT_TEST) += printf_kunit.o
+obj-$(CONFIG_RANDSTRUCT_KUNIT_TEST) += randstruct_kunit.o
+obj-$(CONFIG_SCANF_KUNIT_TEST) += scanf_kunit.o
+obj-$(CONFIG_SEQ_BUF_KUNIT_TEST) += seq_buf_kunit.o
+obj-$(CONFIG_SIPHASH_KUNIT_TEST) += siphash_kunit.o
+obj-$(CONFIG_SLUB_KUNIT_TEST) += slub_kunit.o
+obj-$(CONFIG_TEST_SORT) += test_sort.o
+CFLAGS_stackinit_kunit.o += $(call cc-disable-warning, switch-unreachable)
+obj-$(CONFIG_STACKINIT_KUNIT_TEST) += stackinit_kunit.o
+obj-$(CONFIG_STRING_KUNIT_TEST) += string_kunit.o
+obj-$(CONFIG_STRING_HELPERS_KUNIT_TEST) += string_helpers_kunit.o
+obj-$(CONFIG_USERCOPY_KUNIT_TEST) += usercopy_kunit.o
+obj-$(CONFIG_UTIL_MACROS_KUNIT) += util_macros_kunit.o
+obj-$(CONFIG_RATELIMIT_KUNIT_TEST) += test_ratelimit.o
+obj-$(CONFIG_UUID_KUNIT_TEST) += uuid_kunit.o
+
+obj-$(CONFIG_TEST_RUNTIME_MODULE)		+= module/