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, 25 insertions, 0 deletions

diff --git a/sound/soc/sof/sof-of-dev.h b/sound/soc/sof/sof-of-dev.h
new file mode 100644
index 000000000..b6cc70595
--- /dev/null
+++ b/sound/soc/sof/sof-of-dev.h
@@ -0,0 +1,25 @@
+/* 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 2021 NXP
+ */
+
+#ifndef __SOUND_SOC_SOF_OF_H
+#define __SOUND_SOC_SOF_OF_H
+
+struct snd_sof_of_mach {
+	const char *compatible;
+	const char *drv_name;
+	const char *fw_filename;
+	const char *sof_tplg_filename;
+};
+
+extern const struct dev_pm_ops sof_of_pm;
+
+int sof_of_probe(struct platform_device *pdev);
+void sof_of_remove(struct platform_device *pdev);
+void sof_of_shutdown(struct platform_device *pdev);
+
+#endif