sound/oss: remove offset from load_patch callbacks

Was: [PATCH] sound/oss/midi_synth: prevent underflow, use of
uninitialized value, and signedness issue

The offset passed to midi_synth_load_patch() can be essentially
arbitrary.  If it's greater than the header length, this will result in
a copy_from_user(dst, src, negative_val).  While this will just return
-EFAULT on x86, on other architectures this may cause memory corruption.
Additionally, the length field of the sysex_info structure may not be
initialized prior to its use.  Finally, a signed comparison may result
in an unintentionally large loop.

On suggestion by Takashi Iwai, version two removes the offset argument
from the load_patch callbacks entirely, which also resolves similar
issues in opl3.  Compile tested only.

v3 adjusts comments and hopefully gets copy offsets right.

Signed-off-by: Dan Rosenberg <drosenberg@vsecurity.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

1 files changed, 1 insertions, 1 deletions

diff --git a/sound/oss/midi_synth.h b/sound/oss/midi_synth.h
index 6bc9d00bc77c..b64ddd6c4abc 100644
--- a/sound/oss/midi_synth.h
+++ b/sound/oss/midi_synth.h
@@ -8,7 +8,7 @@ int midi_synth_open (int dev, int mode);
 void midi_synth_close (int dev);
 void midi_synth_hw_control (int dev, unsigned char *event);
 int midi_synth_load_patch (int dev, int format, const char __user * addr,
-                 int offs, int count, int pmgr_flag);
+                 int count, int pmgr_flag);
 void midi_synth_panning (int dev, int channel, int pressure);
 void midi_synth_aftertouch (int dev, int channel, int pressure);
 void midi_synth_controller (int dev, int channel, int ctrl_num, int value);