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sound: ua101: fix division by zero at probe

PATCH Applied Johan Hovold 2 participants 2 messages Oct 26, 2021 – Oct 27, 2021

Subsystems (4)
Stable branch USB Sound Edirol ua-101/ua-1000 driver
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Johan Hovold

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#0 lore raw

PATCH 1/1 sound: ua101: fix division by zero at probe

Add the missing endpoint max-packet sanity check to probe() to avoid division by zero in alloc_stream_buffers() in case a malicious device has broken descriptors (or when doing descriptor fuzz testing).

Note that USB core will reject URBs submitted for endpoints with zero wMaxPacketSize but that drivers doing packet-size calculations still need to handle this (cf. commit 2548288b4fb0 ("USB: Fix: Don't skip endpoint descriptors with maxpacket=0")).

Fixes 63978ab3e3e9 ("sound: add Edirol UA-101 support")
Cc [email protected] # 2.6.34
Signed-off-by Johan Hovold <[email protected]>
---
 sound/usb/misc/ua101.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
sound/usb/misc/ua101.c +2 -2
index 5834d1dc317e..4f6b20ed29dd 100644
@@ -1000,7 +1000,7 @@ static int detect_usb_format(struct ua101 *ua)
 		fmt_playback->bSubframeSize * ua->playback.channels;
 
 	epd = &ua->intf[INTF_CAPTURE]->altsetting[1].endpoint[0].desc;
-	if (!usb_endpoint_is_isoc_in(epd)) {
+	if (!usb_endpoint_is_isoc_in(epd) || usb_endpoint_maxp(epd) == 0) {
 		dev_err(&ua->dev->dev, "invalid capture endpoint\n");
 		return -ENXIO;
 	}

@@ -1008,7 +1008,7 @@ static int detect_usb_format(struct ua101 *ua)
 	ua->capture.max_packet_bytes = usb_endpoint_maxp(epd);
 
 	epd = &ua->intf[INTF_PLAYBACK]->altsetting[1].endpoint[0].desc;
-	if (!usb_endpoint_is_isoc_out(epd)) {
+	if (!usb_endpoint_is_isoc_out(epd) || usb_endpoint_maxp(epd) == 0) {
 		dev_err(&ua->dev->dev, "invalid playback endpoint\n");
 		return -ENXIO;
 	}
Signature · 1 line
2.32.0
Applied
#1 lore raw
Quoted 5 lines · Johan Hovold

Add the missing endpoint max-packet sanity check to probe() to avoid division by zero in alloc_stream_buffers() in case a malicious device has broken descriptors (or when doing descriptor fuzz testing).

Quoted 8 lines

Note that USB core will reject URBs submitted for endpoints with zero wMaxPacketSize but that drivers doing packet-size calculations still need to handle this (cf. commit 2548288b4fb0 ("USB: Fix: Don't skip endpoint descriptors with maxpacket=0")).

Fixes 63978ab3e3e9 ("sound: add Edirol UA-101 support")
Cc [email protected] # 2.6.34
Signed-off-by Johan Hovold <[email protected]>

Thanks, applied.

Takashi