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/dev_table.h b/sound/oss/dev_table.h
index b7617bee6388..0199a317c5a9 100644
--- a/sound/oss/dev_table.h
+++ b/sound/oss/dev_table.h
@@ -271,7 +271,7 @@ struct synth_operations
 	void (*reset) (int dev);
 	void (*hw_control) (int dev, unsigned char *event);
 	int (*load_patch) (int dev, int format, const char __user *addr,
-	     int offs, int count, int pmgr_flag);
+	     int count, int pmgr_flag);
 	void (*aftertouch) (int dev, int voice, int pressure);
 	void (*controller) (int dev, int voice, int ctrl_num, int value);
 	void (*panning) (int dev, int voice, int value);