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, 127 insertions, 0 deletions

diff --git a/sound/soc/sof/iomem-utils.c b/sound/soc/sof/iomem-utils.c
new file mode 100644
index 000000000..f6cb79082
--- /dev/null
+++ b/sound/soc/sof/iomem-utils.c
@@ -0,0 +1,127 @@
+// SPDX-License-Identifier: (GPL-2.0-only OR BSD-3-Clause)
+//
+// This file is provided under a dual BSD/GPLv2 license.  When using or
+// redistributing this file, you may do so under either license.
+//
+// Copyright(c) 2018-2022 Intel Corporation
+//
+// Author: Keyon Jie <yang.jie@linux.intel.com>
+//
+
+#include <linux/io-64-nonatomic-lo-hi.h>
+#include <linux/platform_device.h>
+#include <linux/unaligned.h>
+#include <sound/soc.h>
+#include <sound/sof.h>
+#include "sof-priv.h"
+#include "ops.h"
+
+/*
+ * Register IO
+ *
+ * The sof_io_xyz() wrappers are typically referenced in snd_sof_dsp_ops
+ * structures and cannot be inlined.
+ */
+
+void sof_io_write(struct snd_sof_dev *sdev, void __iomem *addr, u32 value)
+{
+	writel(value, addr);
+}
+EXPORT_SYMBOL(sof_io_write);
+
+u32 sof_io_read(struct snd_sof_dev *sdev, void __iomem *addr)
+{
+	return readl(addr);
+}
+EXPORT_SYMBOL(sof_io_read);
+
+void sof_io_write64(struct snd_sof_dev *sdev, void __iomem *addr, u64 value)
+{
+	writeq(value, addr);
+}
+EXPORT_SYMBOL(sof_io_write64);
+
+u64 sof_io_read64(struct snd_sof_dev *sdev, void __iomem *addr)
+{
+	return readq(addr);
+}
+EXPORT_SYMBOL(sof_io_read64);
+
+/*
+ * IPC Mailbox IO
+ */
+
+void sof_mailbox_write(struct snd_sof_dev *sdev, u32 offset,
+		       void *message, size_t bytes)
+{
+	void __iomem *dest = sdev->bar[sdev->mailbox_bar] + offset;
+
+	memcpy_toio(dest, message, bytes);
+}
+EXPORT_SYMBOL(sof_mailbox_write);
+
+void sof_mailbox_read(struct snd_sof_dev *sdev, u32 offset,
+		      void *message, size_t bytes)
+{
+	void __iomem *src = sdev->bar[sdev->mailbox_bar] + offset;
+
+	memcpy_fromio(message, src, bytes);
+}
+EXPORT_SYMBOL(sof_mailbox_read);
+
+/*
+ * Memory copy.
+ */
+
+int sof_block_write(struct snd_sof_dev *sdev, enum snd_sof_fw_blk_type blk_type,
+		    u32 offset, void *src, size_t size)
+{
+	int bar = snd_sof_dsp_get_bar_index(sdev, blk_type);
+	const u8 *src_byte = src;
+	void __iomem *dest;
+	u32 affected_mask;
+	u32 tmp;
+	int m, n;
+
+	if (bar < 0)
+		return bar;
+
+	dest = sdev->bar[bar] + offset;
+
+	m = size / 4;
+	n = size % 4;
+
+	/* __iowrite32_copy use 32bit size values so divide by 4 */
+	__iowrite32_copy(dest, src, m);
+
+	if (n) {
+		affected_mask = (1 << (8 * n)) - 1;
+
+		/* first read the 32bit data of dest, then change affected
+		 * bytes, and write back to dest. For unaffected bytes, it
+		 * should not be changed
+		 */
+		tmp = ioread32(dest + m * 4);
+		tmp &= ~affected_mask;
+
+		tmp |= *(u32 *)(src_byte + m * 4) & affected_mask;
+		iowrite32(tmp, dest + m * 4);
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(sof_block_write);
+
+int sof_block_read(struct snd_sof_dev *sdev, enum snd_sof_fw_blk_type blk_type,
+		   u32 offset, void *dest, size_t size)
+{
+	int bar = snd_sof_dsp_get_bar_index(sdev, blk_type);
+
+	if (bar < 0)
+		return bar;
+
+	memcpy_fromio(dest, sdev->bar[bar] + offset, size);
+
+	return 0;
+}
+EXPORT_SYMBOL(sof_block_read);