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    Subject[055/129] ALSA: seq/oss - Fix double-free at error path of snd_seq_oss_open()
    2.6.35-stable review patch.  If anyone has any objections, please let us know.

    ------------------

    From: Takashi Iwai <tiwai@suse.de>

    commit 27f7ad53829f79e799a253285318bff79ece15bd upstream.

    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>
    Signed-off-by: Takashi Iwai <tiwai@suse.de>
    Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

    ---
    sound/core/seq/oss/seq_oss_init.c | 9 ++++-----
    1 file changed, 4 insertions(+), 5 deletions(-)

    --- a/sound/core/seq/oss/seq_oss_init.c
    +++ b/sound/core/seq/oss/seq_oss_init.c
    @@ -281,13 +281,10 @@ snd_seq_oss_open(struct file *file, int
    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);



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