Commit 27f7ad53 authored Sep 06, 2010 by Takashi Iwai

ALSA: seq/oss - Fix double-free at error path of snd_seq_oss_open()



The error handling in snd_seq_oss_open() has several bad codes that
do dereferecing released pointers and double-free of kmalloc'ed data.
The object dp is release in free_devinfo() that is called via
private_free callback.  The rest shouldn't touch this object any more.

The patch changes delete_port() to call kfree() in any case, and gets
rid of unnecessary calls of destructors in snd_seq_oss_open().

Fixes CVE-2010-3080.

Reported-and-tested-by: Tavis Ormandy <taviso@cmpxchg8b.com>
Cc: <stable@kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

parent e4ee8dd8

sound/core/seq/oss/seq_oss_init.c

+4 −5

Original line number	Diff line number	Diff line
		@@ -281,13 +281,10 @@ snd_seq_oss_open(struct file *file, int level)
		return 0;

		_error:
		snd_seq_oss_writeq_delete(dp->writeq);
		snd_seq_oss_readq_delete(dp->readq);
		snd_seq_oss_synth_cleanup(dp);
		snd_seq_oss_midi_cleanup(dp);
		delete_port(dp);
		delete_seq_queue(dp->queue);
		kfree(dp);
		delete_port(dp);

		return rc;
		}
		@@ -350,8 +347,10 @@ create_port(struct seq_oss_devinfo *dp)
		static int
		delete_port(struct seq_oss_devinfo *dp)
		{
		if (dp->port < 0)
		if (dp->port < 0) {
		kfree(dp);
		return 0;
		}

		debug_printk(("delete_port %i\n", dp->port));
		return snd_seq_event_port_detach(dp->cseq, dp->port);