| Message ID | s5htvzudg64.wl-tiwai@suse.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Fri, Sep 22, 2017 at 3:19 PM, Takashi Iwai <tiwai@suse.de> wrote: > On Fri, 22 Sep 2017 14:56:06 +0200, > Andrey Konovalov wrote: >> >> Hi! >> >> I've got the following report while fuzzing the kernel with syzkaller. >> >> On commit ebb2c2437d8008d46796902ff390653822af6cc4 (Sep 18). >> >> It seems that there's no check that control_header has enough space >> for uac1_ac_header_descriptor in snd_usb_create_streams(). > > Indeed, this might be an issue. > Does the patch below fix the problem? I believe it does. It does fix the crash with my reproducer. I'm not sure if the (rest_bytes <= 0) check is actually needed though. It seems that if snd_usb_find_csint_desc() returns a non-null value, it'll always be within the buffer. Tested-by: Andrey Konovalov <andreyknvl@google.com> > > > Takashi > > --- > diff --git a/sound/usb/card.c b/sound/usb/card.c > index 3dc36d913550..fc969efbb37c 100644 > --- a/sound/usb/card.c > +++ b/sound/usb/card.c > @@ -221,6 +221,7 @@ static int snd_usb_create_streams(struct snd_usb_audio *chip, int ctrlif) > struct usb_interface_descriptor *altsd; > void *control_header; > int i, protocol; > + int rest_bytes; > > /* find audiocontrol interface */ > host_iface = &usb_ifnum_to_if(dev, ctrlif)->altsetting[0]; > @@ -235,6 +236,13 @@ static int snd_usb_create_streams(struct snd_usb_audio *chip, int ctrlif) > return -EINVAL; > } > > + rest_bytes = (void *)(host_iface->extra + host_iface->extralen) - > + control_header; > + if (rest_bytes <= 0) { > + dev_err(&dev->dev, "invalid control header\n"); > + return -EINVAL; > + } > + > switch (protocol) { > default: > dev_warn(&dev->dev, > @@ -245,11 +253,21 @@ static int snd_usb_create_streams(struct snd_usb_audio *chip, int ctrlif) > case UAC_VERSION_1: { > struct uac1_ac_header_descriptor *h1 = control_header; > > + if (rest_bytes < sizeof(*h1)) { > + dev_err(&dev->dev, "too short v1 buffer descriptor\n"); > + return -EINVAL; > + } > + > if (!h1->bInCollection) { > dev_info(&dev->dev, "skipping empty audio interface (v1)\n"); > return -EINVAL; > } > > + if (rest_bytes < h1->bLength) { > + dev_err(&dev->dev, "invalid buffer length (v1)\n"); > + return -EINVAL; > + } > + > if (h1->bLength < sizeof(*h1) + h1->bInCollection) { > dev_err(&dev->dev, "invalid UAC_HEADER (v1)\n"); > return -EINVAL; > > -- > You received this message because you are subscribed to the Google Groups "syzkaller" group. > To unsubscribe from this group and stop receiving emails from it, send an email to syzkaller+unsubscribe@googlegroups.com. > For more options, visit https://groups.google.com/d/optout.
diff --git a/sound/usb/card.c b/sound/usb/card.c index 3dc36d913550..fc969efbb37c 100644 --- a/sound/usb/card.c +++ b/sound/usb/card.c @@ -221,6 +221,7 @@ static int snd_usb_create_streams(struct snd_usb_audio *chip, int ctrlif) struct usb_interface_descriptor *altsd; void *control_header; int i, protocol; + int rest_bytes; /* find audiocontrol interface */ host_iface = &usb_ifnum_to_if(dev, ctrlif)->altsetting[0]; @@ -235,6 +236,13 @@ static int snd_usb_create_streams(struct snd_usb_audio *chip, int ctrlif) return -EINVAL; } + rest_bytes = (void *)(host_iface->extra + host_iface->extralen) - + control_header; + if (rest_bytes <= 0) { + dev_err(&dev->dev, "invalid control header\n"); + return -EINVAL; + } + switch (protocol) { default: dev_warn(&dev->dev, @@ -245,11 +253,21 @@ static int snd_usb_create_streams(struct snd_usb_audio *chip, int ctrlif) case UAC_VERSION_1: { struct uac1_ac_header_descriptor *h1 = control_header; + if (rest_bytes < sizeof(*h1)) { + dev_err(&dev->dev, "too short v1 buffer descriptor\n"); + return -EINVAL; + } + if (!h1->bInCollection) { dev_info(&dev->dev, "skipping empty audio interface (v1)\n"); return -EINVAL; } + if (rest_bytes < h1->bLength) { + dev_err(&dev->dev, "invalid buffer length (v1)\n"); + return -EINVAL; + } + if (h1->bLength < sizeof(*h1) + h1->bInCollection) { dev_err(&dev->dev, "invalid UAC_HEADER (v1)\n"); return -EINVAL;