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, 47 insertions, 0 deletions

diff --git a/sound/hda/controllers/intel.h b/sound/hda/controllers/intel.h
new file mode 100644
index 000000000..4efb3b0fc
--- /dev/null
+++ b/sound/hda/controllers/intel.h
@@ -0,0 +1,47 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ */
+#ifndef __SOUND_HDA_INTEL_H
+#define __SOUND_HDA_INTEL_H
+
+#include "hda_controller.h"
+
+struct hda_intel {
+	struct azx chip;
+
+	/* sync probing */
+	struct completion probe_wait;
+	struct delayed_work probe_work;
+
+	/* card list (for power_save trigger) */
+	struct list_head list;
+
+	/* extra flags */
+	unsigned int irq_pending_warned:1;
+	unsigned int probe_continued:1;
+	unsigned int runtime_pm_disabled:1;
+
+	/* vga_switcheroo setup */
+	unsigned int use_vga_switcheroo:1;
+	unsigned int vga_switcheroo_registered:1;
+	unsigned int init_failed:1; /* delayed init failed */
+	unsigned int freed:1; /* resources already released */
+
+	bool need_i915_power:1; /* the hda controller needs i915 power */
+
+	int probe_retry;	/* being probe-retry */
+};
+
+struct hda_intel_stream {
+	struct azx_dev azx_dev;
+
+	/* for pending irqs */
+	struct hda_intel *hda;
+	struct work_struct irq_pending_work;
+	bool irq_pending;
+};
+
+#define azx_dev_to_istream(azx_dev) \
+	container_of(azx_dev, struct hda_intel_stream, azx_dev)
+
+#endif