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, 57 insertions, 0 deletions

diff --git a/fs/nls/Makefile b/fs/nls/Makefile
new file mode 100644
index 000000000..5062c699d
--- /dev/null
+++ b/fs/nls/Makefile
@@ -0,0 +1,57 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for native language support
+#
+
+obj-$(CONFIG_NLS)		+= nls_base.o
+
+obj-$(CONFIG_NLS_CODEPAGE_437)	+= nls_cp437.o
+obj-$(CONFIG_NLS_CODEPAGE_737)	+= nls_cp737.o
+obj-$(CONFIG_NLS_CODEPAGE_775)	+= nls_cp775.o
+obj-$(CONFIG_NLS_CODEPAGE_850)	+= nls_cp850.o
+obj-$(CONFIG_NLS_CODEPAGE_852)	+= nls_cp852.o
+obj-$(CONFIG_NLS_CODEPAGE_855)	+= nls_cp855.o
+obj-$(CONFIG_NLS_CODEPAGE_857)	+= nls_cp857.o
+obj-$(CONFIG_NLS_CODEPAGE_860)	+= nls_cp860.o
+obj-$(CONFIG_NLS_CODEPAGE_861)	+= nls_cp861.o
+obj-$(CONFIG_NLS_CODEPAGE_862)	+= nls_cp862.o
+obj-$(CONFIG_NLS_CODEPAGE_863)	+= nls_cp863.o
+obj-$(CONFIG_NLS_CODEPAGE_864)	+= nls_cp864.o
+obj-$(CONFIG_NLS_CODEPAGE_865)	+= nls_cp865.o
+obj-$(CONFIG_NLS_CODEPAGE_866)	+= nls_cp866.o
+obj-$(CONFIG_NLS_CODEPAGE_869)	+= nls_cp869.o
+obj-$(CONFIG_NLS_CODEPAGE_874)	+= nls_cp874.o
+obj-$(CONFIG_NLS_CODEPAGE_932)	+= nls_cp932.o nls_euc-jp.o
+obj-$(CONFIG_NLS_CODEPAGE_936)	+= nls_cp936.o
+obj-$(CONFIG_NLS_CODEPAGE_949)	+= nls_cp949.o
+obj-$(CONFIG_NLS_CODEPAGE_950)	+= nls_cp950.o
+obj-$(CONFIG_NLS_CODEPAGE_1250) += nls_cp1250.o
+obj-$(CONFIG_NLS_CODEPAGE_1251)	+= nls_cp1251.o
+obj-$(CONFIG_NLS_ASCII)		+= nls_ascii.o
+obj-$(CONFIG_NLS_ISO8859_1)	+= nls_iso8859-1.o
+obj-$(CONFIG_NLS_ISO8859_2)	+= nls_iso8859-2.o
+obj-$(CONFIG_NLS_ISO8859_3)	+= nls_iso8859-3.o
+obj-$(CONFIG_NLS_ISO8859_4)	+= nls_iso8859-4.o
+obj-$(CONFIG_NLS_ISO8859_5)	+= nls_iso8859-5.o
+obj-$(CONFIG_NLS_ISO8859_6)	+= nls_iso8859-6.o
+obj-$(CONFIG_NLS_ISO8859_7)	+= nls_iso8859-7.o
+obj-$(CONFIG_NLS_ISO8859_8)	+= nls_cp1255.o
+obj-$(CONFIG_NLS_ISO8859_9)	+= nls_iso8859-9.o
+obj-$(CONFIG_NLS_ISO8859_13)	+= nls_iso8859-13.o
+obj-$(CONFIG_NLS_ISO8859_14)	+= nls_iso8859-14.o
+obj-$(CONFIG_NLS_ISO8859_15)	+= nls_iso8859-15.o
+obj-$(CONFIG_NLS_KOI8_R)	+= nls_koi8-r.o
+obj-$(CONFIG_NLS_KOI8_U)	+= nls_koi8-u.o nls_koi8-ru.o
+obj-$(CONFIG_NLS_UTF8)		+= nls_utf8.o
+obj-$(CONFIG_NLS_MAC_CELTIC)    += mac-celtic.o
+obj-$(CONFIG_NLS_MAC_CENTEURO)  += mac-centeuro.o
+obj-$(CONFIG_NLS_MAC_CROATIAN)  += mac-croatian.o
+obj-$(CONFIG_NLS_MAC_CYRILLIC)  += mac-cyrillic.o
+obj-$(CONFIG_NLS_MAC_GAELIC)    += mac-gaelic.o
+obj-$(CONFIG_NLS_MAC_GREEK)     += mac-greek.o
+obj-$(CONFIG_NLS_MAC_ICELAND)   += mac-iceland.o
+obj-$(CONFIG_NLS_MAC_INUIT)     += mac-inuit.o
+obj-$(CONFIG_NLS_MAC_ROMANIAN)  += mac-romanian.o
+obj-$(CONFIG_NLS_MAC_ROMAN)     += mac-roman.o
+obj-$(CONFIG_NLS_MAC_TURKISH)   += mac-turkish.o
+obj-$(CONFIG_NLS_UCS2_UTILS)		+= nls_ucs2_utils.o