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, 126 insertions, 0 deletions

diff --git a/lib/raid/raid6/Makefile b/lib/raid/raid6/Makefile
new file mode 100644
index 000000000..038d6c74d
--- /dev/null
+++ b/lib/raid/raid6/Makefile
@@ -0,0 +1,126 @@
+# SPDX-License-Identifier: GPL-2.0
+
+ccflags-y			+= -I $(src)
+
+ifeq ($(CONFIG_RAID6_PQ_ARCH),y)
+CFLAGS_algos.o			+= -I$(src)/$(SRCARCH)
+endif
+
+obj-$(CONFIG_RAID6_PQ)		+= raid6_pq.o tests/
+
+raid6_pq-y			+= algos.o tables.o
+
+# generic integer generation and recovery implementation
+raid6_pq-y			+= int1.o int2.o int4.o int8.o
+raid6_pq-y			+= recov.o
+
+# architecture-specific generation and recovery implementations:
+raid6_pq-$(CONFIG_KERNEL_MODE_NEON) += arm/neon.o \
+				   arm/neon1.o \
+				   arm/neon2.o \
+				   arm/neon4.o \
+				   arm/neon8.o \
+				   arm/recov_neon.o \
+				   arm/recov_neon_inner.o
+raid6_pq-$(CONFIG_LOONGARCH)	+= loongarch/loongarch_simd.o \
+				   loongarch/recov_loongarch_simd.o
+raid6_pq-$(CONFIG_ALTIVEC)	+= powerpc/altivec1.o \
+				   powerpc/altivec2.o \
+				   powerpc/altivec4.o \
+				   powerpc/altivec8.o \
+				   powerpc/vpermxor1.o \
+				   powerpc/vpermxor2.o \
+				   powerpc/vpermxor4.o \
+				   powerpc/vpermxor8.o
+raid6_pq-$(CONFIG_RISCV_ISA_V)	+= riscv/rvv.o \
+				   riscv/recov_rvv.o
+raid6_pq-$(CONFIG_S390)		+= s390/s390vx8.o \
+				   s390/recov_s390xc.o
+ifeq ($(CONFIG_X86),y)
+raid6_pq-$(CONFIG_X86_32)	+= x86/mmx.o \
+				   x86/sse1.o
+endif
+raid6_pq-$(CONFIG_X86)		+= x86/sse2.o \
+				   x86/avx2.o \
+				   x86/avx512.o \
+				   x86/recov_ssse3.o \
+				   x86/recov_avx2.o \
+				   x86/recov_avx512.o
+
+hostprogs			+= mktables
+
+CFLAGS_arm/neon1.o += $(CC_FLAGS_FPU)
+CFLAGS_arm/neon2.o += $(CC_FLAGS_FPU)
+CFLAGS_arm/neon4.o += $(CC_FLAGS_FPU)
+CFLAGS_arm/neon8.o += $(CC_FLAGS_FPU)
+CFLAGS_arm/recov_neon_inner.o += $(CC_FLAGS_FPU)
+CFLAGS_REMOVE_arm/neon1.o += $(CC_FLAGS_NO_FPU)
+CFLAGS_REMOVE_arm/neon2.o += $(CC_FLAGS_NO_FPU)
+CFLAGS_REMOVE_arm/neon4.o += $(CC_FLAGS_NO_FPU)
+CFLAGS_REMOVE_arm/neon8.o += $(CC_FLAGS_NO_FPU)
+CFLAGS_REMOVE_arm/recov_neon_inner.o += $(CC_FLAGS_NO_FPU)
+
+ifeq ($(CONFIG_ALTIVEC),y)
+altivec_flags := -maltivec $(call cc-option,-mabi=altivec)
+# Enable <altivec.h>
+altivec_flags += -isystem $(shell $(CC) -print-file-name=include)
+
+CFLAGS_powerpc/altivec1.o += $(altivec_flags)
+CFLAGS_powerpc/altivec2.o += $(altivec_flags)
+CFLAGS_powerpc/altivec4.o += $(altivec_flags)
+CFLAGS_powerpc/altivec8.o += $(altivec_flags)
+CFLAGS_powerpc/vpermxor1.o += $(altivec_flags)
+CFLAGS_powerpc/vpermxor2.o += $(altivec_flags)
+CFLAGS_powerpc/vpermxor4.o += $(altivec_flags)
+CFLAGS_powerpc/vpermxor8.o += $(altivec_flags)
+
+ifdef CONFIG_CC_IS_CLANG
+# clang ppc port does not yet support -maltivec when -msoft-float is
+# enabled. A future release of clang will resolve this
+# https://llvm.org/pr31177
+CFLAGS_REMOVE_powerpc/altivec1.o  += -msoft-float
+CFLAGS_REMOVE_powerpc/altivec2.o  += -msoft-float
+CFLAGS_REMOVE_powerpc/altivec4.o  += -msoft-float
+CFLAGS_REMOVE_powerpc/altivec8.o  += -msoft-float
+CFLAGS_REMOVE_powerpc/vpermxor1.o += -msoft-float
+CFLAGS_REMOVE_powerpc/vpermxor2.o += -msoft-float
+CFLAGS_REMOVE_powerpc/vpermxor4.o += -msoft-float
+CFLAGS_REMOVE_powerpc/vpermxor8.o += -msoft-float
+endif # CONFIG_CC_IS_CLANG
+endif # CONFIG_ALTIVEC
+
+quiet_cmd_mktable = TABLE   $@
+      cmd_mktable = $(obj)/mktables > $@
+
+targets += tables.c
+$(obj)/tables.c: $(obj)/mktables FORCE
+	$(call if_changed,mktable)
+
+quiet_cmd_unroll = UNROLL  $@
+      cmd_unroll = $(AWK) -v N=$* -f $(src)/unroll.awk < $< > $@
+
+targets += int1.c int2.c int4.c int8.c
+$(obj)/int%.c: $(src)/int.uc $(src)/unroll.awk FORCE
+	$(call if_changed,unroll)
+
+targets += arm/neon1.c arm/neon2.c arm/neon4.c arm/neon8.c
+$(obj)/arm/neon%.c: $(src)/arm/neon.uc $(src)/unroll.awk FORCE
+	$(call if_changed,unroll)
+
+targets += powerpc/altivec1.c \
+	   powerpc/altivec2.c \
+	   powerpc/altivec4.c \
+	   powerpc/altivec8.c
+$(obj)/powerpc/altivec%.c: $(src)/powerpc/altivec.uc $(src)/unroll.awk FORCE
+	$(call if_changed,unroll)
+
+targets += powerpc/vpermxor1.c \
+	   powerpc/vpermxor2.c \
+	   powerpc/vpermxor4.c \
+	   powerpc/vpermxor8.c
+$(obj)/powerpc/vpermxor%.c: $(src)/powerpc/vpermxor.uc $(src)/unroll.awk FORCE
+	$(call if_changed,unroll)
+
+targets += s390/s390vx8.c
+$(obj)/s390/s390vx%.c: $(src)/s390/s390vx.uc $(src)/unroll.awk FORCE
+	$(call if_changed,unroll)