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, 67 insertions, 0 deletions

diff --git a/include/sound/hda_component.h b/include/sound/hda_component.h
new file mode 100644
index 000000000..d4804c72d
--- /dev/null
+++ b/include/sound/hda_component.h
@@ -0,0 +1,67 @@
+// SPDX-License-Identifier: GPL-2.0
+// HD-Audio helpers to sync with DRM driver
+
+#ifndef __SOUND_HDA_COMPONENT_H
+#define __SOUND_HDA_COMPONENT_H
+
+#include <drm/drm_audio_component.h>
+#include <sound/hdaudio.h>
+
+/* virtual idx for controller */
+#define HDA_CODEC_IDX_CONTROLLER	HDA_MAX_CODECS
+
+#ifdef CONFIG_SND_HDA_COMPONENT
+int snd_hdac_set_codec_wakeup(struct hdac_bus *bus, bool enable);
+void snd_hdac_display_power(struct hdac_bus *bus, unsigned int idx,
+			    bool enable);
+int snd_hdac_sync_audio_rate(struct hdac_device *codec, hda_nid_t nid,
+			     int dev_id, int rate);
+int snd_hdac_acomp_get_eld(struct hdac_device *codec, hda_nid_t nid, int dev_id,
+			   bool *audio_enabled, char *buffer, int max_bytes);
+int snd_hdac_acomp_init(struct hdac_bus *bus,
+			const struct drm_audio_component_audio_ops *aops,
+			int (*match_master)(struct device *, int, void *),
+			size_t extra_size);
+int snd_hdac_acomp_exit(struct hdac_bus *bus);
+int snd_hdac_acomp_register_notifier(struct hdac_bus *bus,
+				    const struct drm_audio_component_audio_ops *ops);
+#else
+static inline int snd_hdac_set_codec_wakeup(struct hdac_bus *bus, bool enable)
+{
+	return 0;
+}
+static inline void snd_hdac_display_power(struct hdac_bus *bus,
+					  unsigned int idx, bool enable)
+{
+}
+static inline int snd_hdac_sync_audio_rate(struct hdac_device *codec,
+					   hda_nid_t nid, int dev_id, int rate)
+{
+	return 0;
+}
+static inline int snd_hdac_acomp_get_eld(struct hdac_device *codec, hda_nid_t nid,
+					 int dev_id, bool *audio_enabled,
+					 char *buffer, int max_bytes)
+{
+	return -ENODEV;
+}
+static inline int snd_hdac_acomp_init(struct hdac_bus *bus,
+				      const struct drm_audio_component_audio_ops *aops,
+				      int (*match_master)(struct device *,
+							  int, void *),
+				      size_t extra_size)
+{
+	return -ENODEV;
+}
+static inline int snd_hdac_acomp_exit(struct hdac_bus *bus)
+{
+	return 0;
+}
+static inline int snd_hdac_acomp_register_notifier(struct hdac_bus *bus,
+						  const struct drm_audio_component_audio_ops *ops)
+{
+	return -ENODEV;
+}
+#endif
+
+#endif /* __SOUND_HDA_COMPONENT_H */