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, 72 insertions, 0 deletions

diff --git a/drivers/clk/mediatek/reset.h b/drivers/clk/mediatek/reset.h
new file mode 100644
index 000000000..562ffd290
--- /dev/null
+++ b/drivers/clk/mediatek/reset.h
@@ -0,0 +1,72 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (c) 2022 MediaTek Inc.
+ */
+
+#ifndef __DRV_CLK_MTK_RESET_H
+#define __DRV_CLK_MTK_RESET_H
+
+#include <linux/reset-controller.h>
+#include <linux/types.h>
+
+#define RST_NR_PER_BANK 32
+
+/* Infra global controller reset set register */
+#define INFRA_RST0_SET_OFFSET 0x120
+#define INFRA_RST1_SET_OFFSET 0x130
+#define INFRA_RST2_SET_OFFSET 0x140
+#define INFRA_RST3_SET_OFFSET 0x150
+#define INFRA_RST4_SET_OFFSET 0x730
+
+/**
+ * enum mtk_reset_version - Version of MediaTek clock reset controller.
+ * @MTK_RST_SIMPLE: Use the same registers for bit set and clear.
+ * @MTK_RST_SET_CLR: Use separate registers for bit set and clear.
+ * @MTK_RST_MAX: Total quantity of version for MediaTek clock reset controller.
+ */
+enum mtk_reset_version {
+	MTK_RST_SIMPLE = 0,
+	MTK_RST_SET_CLR,
+	MTK_RST_MAX,
+};
+
+/**
+ * struct mtk_clk_rst_desc - Description of MediaTek clock reset.
+ * @version: Reset version which is defined in enum mtk_reset_version.
+ * @rst_bank_ofs: Pointer to an array containing base offsets of the reset register.
+ * @rst_bank_nr: Quantity of reset bank.
+ * @rst_idx_map:Pointer to an array containing ids if input argument is index.
+ *		This array is not necessary if our input argument does not mean index.
+ * @rst_idx_map_nr: Quantity of reset index map.
+ */
+struct mtk_clk_rst_desc {
+	enum mtk_reset_version version;
+	u16 *rst_bank_ofs;
+	u32 rst_bank_nr;
+	u16 *rst_idx_map;
+	u32 rst_idx_map_nr;
+};
+
+/**
+ * struct mtk_clk_rst_data - Data of MediaTek clock reset controller.
+ * @regmap: Pointer to base address of reset register address.
+ * @rcdev: Reset controller device.
+ * @desc: Pointer to description of the reset controller.
+ */
+struct mtk_clk_rst_data {
+	struct regmap *regmap;
+	struct reset_controller_dev rcdev;
+	const struct mtk_clk_rst_desc *desc;
+};
+
+/**
+ * mtk_register_reset_controller - Register mediatek clock reset controller with device
+ * @np: Pointer to device.
+ * @desc: Constant pointer to description of clock reset.
+ *
+ * Return: 0 on success and errorno otherwise.
+ */
+int mtk_register_reset_controller_with_dev(struct device *dev,
+					   const struct mtk_clk_rst_desc *desc);
+
+#endif /* __DRV_CLK_MTK_RESET_H */