[alsa-devel] [PATCH] ALSA: usb-audio: Sanity checks for each pipe and EP types

[Takashi Iwai]

The recent USB core code performs sanity checks for the given pipe and
EP types, and it can be hit by manipulated USB descriptors by syzbot.
For making syzbot happier, this patch introduces a local helper for a
sanity check in the driver side and calls it at each place before the
message handling, so that we can avoid the WARNING splats.

Reported-by: syzbot+d952e5e28f5fb7718d23 at syzkaller.appspotmail.com
Signed-off-by: Takashi Iwai <tiwai at suse.de>
---
 sound/usb/helper.c | 17 +++++++++++++++++
 sound/usb/helper.h |  1 +
 sound/usb/quirks.c | 18 +++++++++++++++---
 3 files changed, 33 insertions(+), 3 deletions(-)

diff --git a/sound/usb/helper.c b/sound/usb/helper.c
index 7712e2b84183..b1cc9499c57e 100644
--- a/sound/usb/helper.c
+++ b/sound/usb/helper.c
@@ -76,6 +76,20 @@ void *snd_usb_find_csint_desc(void *buffer, int buflen, void *after, u8 dsubtype
 	return NULL;
 }
 
+/* check the validity of pipe and EP types */
+int snd_usb_pipe_sanity_check(struct usb_device *dev, unsigned int pipe)
+{
+	static const int pipetypes[4] = {
+		PIPE_CONTROL, PIPE_ISOCHRONOUS, PIPE_BULK, PIPE_INTERRUPT
+	};
+	struct usb_host_endpoint *ep;
+
+	ep = usb_pipe_endpoint(dev, pipe);
+	if (usb_pipetype(pipe) != pipetypes[usb_endpoint_type(&ep->desc)])
+		return -EINVAL;
+	return 0;
+}
+
 /*
  * Wrapper for usb_control_msg().
  * Allocates a temp buffer to prevent dmaing from/to the stack.
@@ -88,6 +102,9 @@ int snd_usb_ctl_msg(struct usb_device *dev, unsigned int pipe, __u8 request,
 	void *buf = NULL;
 	int timeout;
 
+	if (snd_usb_pipe_sanity_check(dev, pipe))
+		return -EINVAL;
+
 	if (size > 0) {
 		buf = kmemdup(data, size, GFP_KERNEL);
 		if (!buf)
diff --git a/sound/usb/helper.h b/sound/usb/helper.h
index d338bd0e0ca6..6afb70156ec4 100644
--- a/sound/usb/helper.h
+++ b/sound/usb/helper.h
@@ -7,6 +7,7 @@ unsigned int snd_usb_combine_bytes(unsigned char *bytes, int size);
 void *snd_usb_find_desc(void *descstart, int desclen, void *after, u8 dtype);
 void *snd_usb_find_csint_desc(void *descstart, int desclen, void *after, u8 dsubtype);
 
+int snd_usb_pipe_sanity_check(struct usb_device *dev, unsigned int pipe);
 int snd_usb_ctl_msg(struct usb_device *dev, unsigned int pipe,
 		    __u8 request, __u8 requesttype, __u16 value, __u16 index,
 		    void *data, __u16 size);
diff --git a/sound/usb/quirks.c b/sound/usb/quirks.c
index e6ce1bbe6ca6..057143330a28 100644
--- a/sound/usb/quirks.c
+++ b/sound/usb/quirks.c
@@ -840,11 +840,13 @@ static int snd_usb_novation_boot_quirk(struct usb_device *dev)
 static int snd_usb_accessmusic_boot_quirk(struct usb_device *dev)
 {
 	int err, actual_length;
-
 	/* "midi send" enable */
 	static const u8 seq[] = { 0x4e, 0x73, 0x52, 0x01 };
+	void *buf;
 
-	void *buf = kmemdup(seq, ARRAY_SIZE(seq), GFP_KERNEL);
+	if (snd_usb_pipe_sanity_check(dev, usb_sndintpipe(dev, 0x05)))
+		return -EINVAL;
+	buf = kmemdup(seq, ARRAY_SIZE(seq), GFP_KERNEL);
 	if (!buf)
 		return -ENOMEM;
 	err = usb_interrupt_msg(dev, usb_sndintpipe(dev, 0x05), buf,
@@ -869,7 +871,11 @@ static int snd_usb_accessmusic_boot_quirk(struct usb_device *dev)
 
 static int snd_usb_nativeinstruments_boot_quirk(struct usb_device *dev)
 {
-	int ret = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
+	int ret;
+
+	if (snd_usb_pipe_sanity_check(dev, usb_sndctrlpipe(dev, 0)))
+		return -EINVAL;
+	ret = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
 				  0xaf, USB_TYPE_VENDOR | USB_RECIP_DEVICE,
 				  1, 0, NULL, 0, 1000);
 
@@ -976,6 +982,8 @@ static int snd_usb_axefx3_boot_quirk(struct usb_device *dev)
 
 	dev_dbg(&dev->dev, "Waiting for Axe-Fx III to boot up...\n");
 
+	if (snd_usb_pipe_sanity_check(dev, usb_sndctrlpipe(dev, 0)))
+		return -EINVAL;
 	/* If the Axe-Fx III has not fully booted, it will timeout when trying
 	 * to enable the audio streaming interface. A more generous timeout is
 	 * used here to detect when the Axe-Fx III has finished booting as the
@@ -1008,6 +1016,8 @@ static int snd_usb_motu_microbookii_communicate(struct usb_device *dev, u8 *buf,
 {
 	int err, actual_length;
 
+	if (snd_usb_pipe_sanity_check(dev, usb_sndintpipe(dev, 0x01)))
+		return -EINVAL;
 	err = usb_interrupt_msg(dev, usb_sndintpipe(dev, 0x01), buf, *length,
 				&actual_length, 1000);
 	if (err < 0)
@@ -1018,6 +1028,8 @@ static int snd_usb_motu_microbookii_communicate(struct usb_device *dev, u8 *buf,
 
 	memset(buf, 0, buf_size);
 
+	if (snd_usb_pipe_sanity_check(dev, usb_rcvintpipe(dev, 0x82)))
+		return -EINVAL;
 	err = usb_interrupt_msg(dev, usb_rcvintpipe(dev, 0x82), buf, buf_size,
 				&actual_length, 1000);
 	if (err < 0)
-- 
2.16.4