From 8e5c3482b5c7bcbd7df6b10ddb6d7bcc578f3553 Mon Sep 17 00:00:00 2001 From: Takashi Iwai Date: Tue, 15 Mar 2016 12:09:10 +0100 Subject: [PATCH] ALSA: usb-audio: Fix NULL dereference in create_fixed_stream_quirk() commit 0f886ca12765d20124bd06291c82951fd49a33be upstream. create_fixed_stream_quirk() may cause a NULL-pointer dereference by accessing the non-existing endpoint when a USB device with a malformed USB descriptor is used. This patch avoids it simply by adding a sanity check of bNumEndpoints before the accesses. Bugzilla: https://bugzilla.suse.com/show_bug.cgi?id=971125 Signed-off-by: Takashi Iwai [bwh: Backported to 3.2: - There's no altsd variable - Adjust context] Signed-off-by: Ben Hutchings --- sound/usb/quirks.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/sound/usb/quirks.c b/sound/usb/quirks.c index b01d3cf3759e..c5e912e74139 100644 --- a/sound/usb/quirks.c +++ b/sound/usb/quirks.c @@ -165,6 +165,12 @@ static int create_fixed_stream_quirk(struct snd_usb_audio *chip, return -EINVAL; } alts = &iface->altsetting[fp->altset_idx]; + if (get_iface_desc(alts)->bNumEndpoints < 1) { + kfree(fp); + kfree(rate_table); + return -EINVAL; + } + fp->datainterval = snd_usb_parse_datainterval(chip, alts); fp->maxpacksize = le16_to_cpu(get_endpoint(alts, 0)->wMaxPacketSize); usb_set_interface(chip->dev, fp->iface, 0); -- 2.39.2