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, 32 insertions, 0 deletions

diff --git a/drivers/mtd/hyperbus/Kconfig b/drivers/mtd/hyperbus/Kconfig
new file mode 100644
index 000000000..30ffc4c16
--- /dev/null
+++ b/drivers/mtd/hyperbus/Kconfig
@@ -0,0 +1,32 @@
+menuconfig MTD_HYPERBUS
+	tristate "HyperBus support"
+	depends on HAS_IOMEM
+	select MTD_CFI
+	select MTD_MAP_BANK_WIDTH_2
+	select MTD_CFI_AMDSTD
+	select MTD_COMPLEX_MAPPINGS
+	help
+	  This is the framework for the HyperBus which can be used by
+	  the HyperBus Controller driver to communicate with
+	  HyperFlash. See Cypress HyperBus specification for more
+	  details
+
+if MTD_HYPERBUS
+
+config HBMC_AM654
+	tristate "HyperBus controller driver for AM65x SoC"
+	depends on ARCH_K3 || COMPILE_TEST
+	select MULTIPLEXER
+	imply MUX_MMIO
+	help
+	 This is the driver for HyperBus controller on TI's AM65x and
+	 other SoCs
+
+config RPCIF_HYPERBUS
+	tristate "Renesas RPC-IF HyperBus driver"
+	depends on RENESAS_RPCIF
+	depends on MTD_CFI_BE_BYTE_SWAP
+	help
+	  This option includes Renesas RPC-IF HyperBus support.
+
+endif # MTD_HYPERBUS