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, 77 insertions, 0 deletions

diff --git a/include/dt-bindings/clock/mpc512x-clock.h b/include/dt-bindings/clock/mpc512x-clock.h
new file mode 100644
index 000000000..13c316bf2
--- /dev/null
+++ b/include/dt-bindings/clock/mpc512x-clock.h
@@ -0,0 +1,77 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * This header provides constants for MPC512x clock specs in DT bindings.
+ */
+
+#ifndef _DT_BINDINGS_CLOCK_MPC512x_CLOCK_H
+#define _DT_BINDINGS_CLOCK_MPC512x_CLOCK_H
+
+#define MPC512x_CLK_DUMMY		0
+#define MPC512x_CLK_REF			1
+#define MPC512x_CLK_SYS			2
+#define MPC512x_CLK_DIU			3
+#define MPC512x_CLK_VIU			4
+#define MPC512x_CLK_CSB			5
+#define MPC512x_CLK_E300		6
+#define MPC512x_CLK_IPS			7
+#define MPC512x_CLK_FEC			8
+#define MPC512x_CLK_SATA		9
+#define MPC512x_CLK_PATA		10
+#define MPC512x_CLK_NFC			11
+#define MPC512x_CLK_LPC			12
+#define MPC512x_CLK_MBX_BUS		13
+#define MPC512x_CLK_MBX			14
+#define MPC512x_CLK_MBX_3D		15
+#define MPC512x_CLK_AXE			16
+#define MPC512x_CLK_USB1		17
+#define MPC512x_CLK_USB2		18
+#define MPC512x_CLK_I2C			19
+#define MPC512x_CLK_MSCAN0_MCLK		20
+#define MPC512x_CLK_MSCAN1_MCLK		21
+#define MPC512x_CLK_MSCAN2_MCLK		22
+#define MPC512x_CLK_MSCAN3_MCLK		23
+#define MPC512x_CLK_BDLC		24
+#define MPC512x_CLK_SDHC		25
+#define MPC512x_CLK_PCI			26
+#define MPC512x_CLK_PSC_MCLK_IN		27
+#define MPC512x_CLK_SPDIF_TX		28
+#define MPC512x_CLK_SPDIF_RX		29
+#define MPC512x_CLK_SPDIF_MCLK		30
+#define MPC512x_CLK_SPDIF		31
+#define MPC512x_CLK_AC97		32
+#define MPC512x_CLK_PSC0_MCLK		33
+#define MPC512x_CLK_PSC1_MCLK		34
+#define MPC512x_CLK_PSC2_MCLK		35
+#define MPC512x_CLK_PSC3_MCLK		36
+#define MPC512x_CLK_PSC4_MCLK		37
+#define MPC512x_CLK_PSC5_MCLK		38
+#define MPC512x_CLK_PSC6_MCLK		39
+#define MPC512x_CLK_PSC7_MCLK		40
+#define MPC512x_CLK_PSC8_MCLK		41
+#define MPC512x_CLK_PSC9_MCLK		42
+#define MPC512x_CLK_PSC10_MCLK		43
+#define MPC512x_CLK_PSC11_MCLK		44
+#define MPC512x_CLK_PSC_FIFO		45
+#define MPC512x_CLK_PSC0		46
+#define MPC512x_CLK_PSC1		47
+#define MPC512x_CLK_PSC2		48
+#define MPC512x_CLK_PSC3		49
+#define MPC512x_CLK_PSC4		50
+#define MPC512x_CLK_PSC5		51
+#define MPC512x_CLK_PSC6		52
+#define MPC512x_CLK_PSC7		53
+#define MPC512x_CLK_PSC8		54
+#define MPC512x_CLK_PSC9		55
+#define MPC512x_CLK_PSC10		56
+#define MPC512x_CLK_PSC11		57
+#define MPC512x_CLK_SDHC2		58
+#define MPC512x_CLK_FEC2		59
+#define MPC512x_CLK_OUT0_CLK		60
+#define MPC512x_CLK_OUT1_CLK		61
+#define MPC512x_CLK_OUT2_CLK		62
+#define MPC512x_CLK_OUT3_CLK		63
+#define MPC512x_CLK_CAN_CLK_IN		64
+
+#define MPC512x_CLK_LAST_PUBLIC		64
+
+#endif