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, 39 insertions, 0 deletions

diff --git a/net/mptcp/Kconfig b/net/mptcp/Kconfig
new file mode 100644
index 000000000..be71fc9b4
--- /dev/null
+++ b/net/mptcp/Kconfig
@@ -0,0 +1,39 @@
+
+config MPTCP
+	bool "MPTCP: Multipath TCP"
+	depends on INET
+	select SKB_EXTENSIONS
+	select CRYPTO_LIB_SHA256
+	select CRYPTO_LIB_UTILS
+	help
+	  Multipath TCP (MPTCP) connections send and receive data over multiple
+	  subflows in order to utilize multiple network paths. Each subflow
+	  uses the TCP protocol, and TCP options carry header information for
+	  MPTCP.
+
+if MPTCP
+
+config INET_MPTCP_DIAG
+	depends on INET_DIAG
+	def_tristate INET_DIAG
+
+config MPTCP_IPV6
+	bool "MPTCP: IPv6 support for Multipath TCP"
+	depends on IPV6=y
+	default y
+
+config MPTCP_KUNIT_TEST
+	tristate "This builds the MPTCP KUnit tests" if !KUNIT_ALL_TESTS
+	depends on KUNIT
+	default KUNIT_ALL_TESTS
+	help
+	  Currently covers the MPTCP crypto and token helpers.
+	  Only useful for kernel devs running KUnit test harness and are not
+	  for inclusion into a production build.
+
+	  For more information on KUnit and unit tests in general please refer
+	  to the KUnit documentation in Documentation/dev-tools/kunit/.
+
+	  If unsure, say N.
+
+endif