| Message ID | 20190328133503.6490-1-peter.maydell@linaro.org |
|---|---|
| State | New |
| Headers | show |
| Series | [for-4.0] hw/usb/bus.c: Handle "no speed matched" case in usb_mask_to_str() | expand |
Le jeu. 28 mars 2019 14:36, Peter Maydell <peter.maydell@linaro.org> a écrit : > In usb_mask_to_str() we convert a mask of USB speeds into > a human-readable string (like "full+high") for use in > tracing and error messages. However the conversion code > doesn't do anything to the string buffer if the passed in > speedmask doesn't match any of the recognized speeds, > which means that the tracing and error messages will > end up with random garbage in them. This can happen if > we're doing USB device passthrough. > > Handle the "unrecognized speed" case by using the > string "unknown". > > Fixes: https://bugs.launchpad.net/qemu/+bug/1603785 > Signed-off-by: Peter Maydell <peter.maydell@linaro.org> > --- > Tested by temporarily fiddling with the callsites to > pass in a 0 speedmask, since I don't have any USB passthrough > stuff handy. > --- > hw/usb/bus.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/hw/usb/bus.c b/hw/usb/bus.c > index 6fffab7bfa4..9a74dc95601 100644 > --- a/hw/usb/bus.c > +++ b/hw/usb/bus.c > @@ -500,6 +500,10 @@ static void usb_mask_to_str(char *dest, size_t size, > speeds[i].name); > } > } > + > + if (pos == 0) { > + snprintf(dest, size, "unknown"); > + } > } > > void usb_check_attach(USBDevice *dev, Error **errp) > -- > 2.20.1 > Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org> >
diff --git a/hw/usb/bus.c b/hw/usb/bus.c index 6fffab7bfa4..9a74dc95601 100644 --- a/hw/usb/bus.c +++ b/hw/usb/bus.c @@ -500,6 +500,10 @@ static void usb_mask_to_str(char *dest, size_t size, speeds[i].name); } } + + if (pos == 0) { + snprintf(dest, size, "unknown"); + } } void usb_check_attach(USBDevice *dev, Error **errp)
In usb_mask_to_str() we convert a mask of USB speeds into a human-readable string (like "full+high") for use in tracing and error messages. However the conversion code doesn't do anything to the string buffer if the passed in speedmask doesn't match any of the recognized speeds, which means that the tracing and error messages will end up with random garbage in them. This can happen if we're doing USB device passthrough. Handle the "unrecognized speed" case by using the string "unknown". Fixes: https://bugs.launchpad.net/qemu/+bug/1603785 Signed-off-by: Peter Maydell <peter.maydell@linaro.org> --- Tested by temporarily fiddling with the callsites to pass in a 0 speedmask, since I don't have any USB passthrough stuff handy. --- hw/usb/bus.c | 4 ++++ 1 file changed, 4 insertions(+)