From b769f49463711205d57286e64cf535ed4daf59e9 Mon Sep 17 00:00:00 2001 From: Dan Rosenberg Date: Wed, 23 Mar 2011 10:53:41 -0400 Subject: 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 Signed-off-by: Takashi Iwai --- sound/oss/sequencer.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'sound/oss/sequencer.c') diff --git a/sound/oss/sequencer.c b/sound/oss/sequencer.c index 5ea1098ac427..30bcfe470f83 100644 --- a/sound/oss/sequencer.c +++ b/sound/oss/sequencer.c @@ -241,7 +241,7 @@ int sequencer_write(int dev, struct file *file, const char __user *buf, int coun return -ENXIO; fmt = (*(short *) &event_rec[0]) & 0xffff; - err = synth_devs[dev]->load_patch(dev, fmt, buf, p + 4, c, 0); + err = synth_devs[dev]->load_patch(dev, fmt, buf + p, c, 0); if (err < 0) return err; -- cgit v1.2.3