* [PATCH] hw/usb/hcd-dwc2: Enforce epnum to 0 for the control endpoint to avoid the assertion failure in usb_ep_get()
@ 2021-06-27 3:28 Qiang Liu
2021-06-27 5:21 ` Qiang Liu
0 siblings, 1 reply; 5+ messages in thread
From: Qiang Liu @ 2021-06-27 3:28 UTC (permalink / raw)
Cc: open list:All patches CC here, Qiang Liu, Gerd Hoffmann, Paul Zimmerman
When eptype is USB_ENDPOINT_XFER_CONTROL and pid is
TSIZ_SC_MC_PID_SETUP, usb_ep_get() should return the control endpoint.
In hw/usb/core.c, the assumed epnum of the control endpoint is 0. When
epnum is not 0, usb_ep_get() will crash due to the check assert(pid ==
USB_TOKEN_IN || pid == USB_TOKEN_OUT).
The description
http://www.capital-micro.com/PDF/CME-M7_Family_User_Guide_EN.pdf
(18.5.3.4 (14), 18.5.3.4 (10)) a) mentions that the pid is maintained by
the host, b) but doesn't mention that whether the epnum should be 0 for
the control endpoint. However, usb_ep_get() assumes it is 0. To avoid
potential assertion failure in usb_ep_get(), we could enforce epnum to 0
and warn users.
Fixes: 153ef1662c3 ("dwc-hsotg (dwc2) USB host controller emulation")
Signed-off-by: Qiang Liu <cyruscyliu@gmail.com>
---
hw/usb/hcd-dwc2.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/hw/usb/hcd-dwc2.c b/hw/usb/hcd-dwc2.c
index e1d96ac..65d9d46 100644
--- a/hw/usb/hcd-dwc2.c
+++ b/hw/usb/hcd-dwc2.c
@@ -636,6 +636,11 @@ static void dwc2_enable_chan(DWC2State *s, uint32_t index)
}
if (eptype == USB_ENDPOINT_XFER_CONTROL && pid == TSIZ_SC_MC_PID_SETUP) {
+ if (epnum != 0) {
+ qemu_log_mask(LOG_GUEST_ERROR,
+ "epnum should be 0 for the control endpoint\n");
+ epnum = 0;
+ }
pid = USB_TOKEN_SETUP;
} else {
pid = epdir ? USB_TOKEN_IN : USB_TOKEN_OUT;
--
2.7.4
^ permalink raw reply related [flat|nested] 5+ messages in thread* Re: [PATCH] hw/usb/hcd-dwc2: Enforce epnum to 0 for the control endpoint to avoid the assertion failure in usb_ep_get() 2021-06-27 3:28 [PATCH] hw/usb/hcd-dwc2: Enforce epnum to 0 for the control endpoint to avoid the assertion failure in usb_ep_get() Qiang Liu @ 2021-06-27 5:21 ` Qiang Liu 2021-07-04 22:27 ` Paul Zimmerman 0 siblings, 1 reply; 5+ messages in thread From: Qiang Liu @ 2021-06-27 5:21 UTC (permalink / raw) Cc: open list:All patches CC here, Gerd Hoffmann, Paul Zimmerman Hi folks, I found this bug by my dwc2 fuzzer. It seems that * https://bugs.launchpad.net/qemu/+bug/1907042 * https://bugs.launchpad.net/qemu/+bug/1525123 or * https://gitlab.com/qemu-project/qemu/-/issues/119 * https://gitlab.com/qemu-project/qemu/-/issues/303 have reported similar issues. Would it be better to consider and fix them together? Best, Qiang On Sun, Jun 27, 2021 at 11:28 AM Qiang Liu <cyruscyliu@gmail.com> wrote: > > When eptype is USB_ENDPOINT_XFER_CONTROL and pid is > TSIZ_SC_MC_PID_SETUP, usb_ep_get() should return the control endpoint. > In hw/usb/core.c, the assumed epnum of the control endpoint is 0. When > epnum is not 0, usb_ep_get() will crash due to the check assert(pid == > USB_TOKEN_IN || pid == USB_TOKEN_OUT). > > The description > http://www.capital-micro.com/PDF/CME-M7_Family_User_Guide_EN.pdf > (18.5.3.4 (14), 18.5.3.4 (10)) a) mentions that the pid is maintained by > the host, b) but doesn't mention that whether the epnum should be 0 for > the control endpoint. However, usb_ep_get() assumes it is 0. To avoid > potential assertion failure in usb_ep_get(), we could enforce epnum to 0 > and warn users. > > Fixes: 153ef1662c3 ("dwc-hsotg (dwc2) USB host controller emulation") > Signed-off-by: Qiang Liu <cyruscyliu@gmail.com> > --- > hw/usb/hcd-dwc2.c | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/hw/usb/hcd-dwc2.c b/hw/usb/hcd-dwc2.c > index e1d96ac..65d9d46 100644 > --- a/hw/usb/hcd-dwc2.c > +++ b/hw/usb/hcd-dwc2.c > @@ -636,6 +636,11 @@ static void dwc2_enable_chan(DWC2State *s, uint32_t index) > } > > if (eptype == USB_ENDPOINT_XFER_CONTROL && pid == TSIZ_SC_MC_PID_SETUP) { > + if (epnum != 0) { > + qemu_log_mask(LOG_GUEST_ERROR, > + "epnum should be 0 for the control endpoint\n"); > + epnum = 0; > + } > pid = USB_TOKEN_SETUP; > } else { > pid = epdir ? USB_TOKEN_IN : USB_TOKEN_OUT; > -- > 2.7.4 > ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] hw/usb/hcd-dwc2: Enforce epnum to 0 for the control endpoint to avoid the assertion failure in usb_ep_get() 2021-06-27 5:21 ` Qiang Liu @ 2021-07-04 22:27 ` Paul Zimmerman 2021-07-05 1:34 ` Qiang Liu 0 siblings, 1 reply; 5+ messages in thread From: Paul Zimmerman @ 2021-07-04 22:27 UTC (permalink / raw) To: Qiang Liu; +Cc: Gerd Hoffmann, open list:All patches CC here On Sat, Jun 26, 2021 at 10:21 PM Qiang Liu <cyruscyliu@gmail.com> wrote: > > Hi folks, > > I found this bug by my dwc2 fuzzer. > It seems that > * https://bugs.launchpad.net/qemu/+bug/1907042 > * https://bugs.launchpad.net/qemu/+bug/1525123 > or > * https://gitlab.com/qemu-project/qemu/-/issues/119 > * https://gitlab.com/qemu-project/qemu/-/issues/303 > have reported similar issues. > > Would it be better to consider and fix them together? > > Best, > Qiang > > On Sun, Jun 27, 2021 at 11:28 AM Qiang Liu <cyruscyliu@gmail.com> wrote: > > > > When eptype is USB_ENDPOINT_XFER_CONTROL and pid is > > TSIZ_SC_MC_PID_SETUP, usb_ep_get() should return the control endpoint. > > In hw/usb/core.c, the assumed epnum of the control endpoint is 0. When > > epnum is not 0, usb_ep_get() will crash due to the check assert(pid == > > USB_TOKEN_IN || pid == USB_TOKEN_OUT). > > > > The description > > http://www.capital-micro.com/PDF/CME-M7_Family_User_Guide_EN.pdf > > (18.5.3.4 (14), 18.5.3.4 (10)) a) mentions that the pid is maintained by > > the host, b) but doesn't mention that whether the epnum should be 0 for > > the control endpoint. However, usb_ep_get() assumes it is 0. To avoid > > potential assertion failure in usb_ep_get(), we could enforce epnum to 0 > > and warn users. > > > > Fixes: 153ef1662c3 ("dwc-hsotg (dwc2) USB host controller emulation") > > Signed-off-by: Qiang Liu <cyruscyliu@gmail.com> > > --- > > hw/usb/hcd-dwc2.c | 5 +++++ > > 1 file changed, 5 insertions(+) > > > > diff --git a/hw/usb/hcd-dwc2.c b/hw/usb/hcd-dwc2.c > > index e1d96ac..65d9d46 100644 > > --- a/hw/usb/hcd-dwc2.c > > +++ b/hw/usb/hcd-dwc2.c > > @@ -636,6 +636,11 @@ static void dwc2_enable_chan(DWC2State *s, uint32_t index) > > } > > > > if (eptype == USB_ENDPOINT_XFER_CONTROL && pid == TSIZ_SC_MC_PID_SETUP) { > > + if (epnum != 0) { > > + qemu_log_mask(LOG_GUEST_ERROR, > > + "epnum should be 0 for the control endpoint\n"); > > + epnum = 0; > > + } > > pid = USB_TOKEN_SETUP; > > } else { > > pid = epdir ? USB_TOKEN_IN : USB_TOKEN_OUT; > > -- > > 2.7.4 > > Hi Qiang, Sorry for the late reply, I've had a busy week. Yes, I think it would be best to fix this in the core since it affects more than one host. I'm not sure that forcing the Control endpoint to 0 is the best solution though, perhaps it would be better to print an error message and fail the operation? AFAIK there are no real-world devices that have Control endpoints other than 0, although I believe it is allowed by the USB spec. Let's wait and see what Gerd thinks. - Paul ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] hw/usb/hcd-dwc2: Enforce epnum to 0 for the control endpoint to avoid the assertion failure in usb_ep_get() 2021-07-04 22:27 ` Paul Zimmerman @ 2021-07-05 1:34 ` Qiang Liu 2021-07-21 11:44 ` Gerd Hoffmann 0 siblings, 1 reply; 5+ messages in thread From: Qiang Liu @ 2021-07-05 1:34 UTC (permalink / raw) To: Paul Zimmerman; +Cc: Gerd Hoffmann, open list:All patches CC here Hi Paul, On Mon, Jul 5, 2021 at 6:27 AM Paul Zimmerman <pauldzim@gmail.com> wrote: > > On Sat, Jun 26, 2021 at 10:21 PM Qiang Liu <cyruscyliu@gmail.com> wrote: > > > > Hi folks, > > > > I found this bug by my dwc2 fuzzer. > > It seems that > > * https://bugs.launchpad.net/qemu/+bug/1907042 > > * https://bugs.launchpad.net/qemu/+bug/1525123 > > or > > * https://gitlab.com/qemu-project/qemu/-/issues/119 > > * https://gitlab.com/qemu-project/qemu/-/issues/303 > > have reported similar issues. > > > > Would it be better to consider and fix them together? > > > > Best, > > Qiang > > > > On Sun, Jun 27, 2021 at 11:28 AM Qiang Liu <cyruscyliu@gmail.com> wrote: > > > > > > When eptype is USB_ENDPOINT_XFER_CONTROL and pid is > > > TSIZ_SC_MC_PID_SETUP, usb_ep_get() should return the control endpoint. > > > In hw/usb/core.c, the assumed epnum of the control endpoint is 0. When > > > epnum is not 0, usb_ep_get() will crash due to the check assert(pid == > > > USB_TOKEN_IN || pid == USB_TOKEN_OUT). > > > > > > The description > > > http://www.capital-micro.com/PDF/CME-M7_Family_User_Guide_EN.pdf > > > (18.5.3.4 (14), 18.5.3.4 (10)) a) mentions that the pid is maintained by > > > the host, b) but doesn't mention that whether the epnum should be 0 for > > > the control endpoint. However, usb_ep_get() assumes it is 0. To avoid > > > potential assertion failure in usb_ep_get(), we could enforce epnum to 0 > > > and warn users. > > > > > > Fixes: 153ef1662c3 ("dwc-hsotg (dwc2) USB host controller emulation") > > > Signed-off-by: Qiang Liu <cyruscyliu@gmail.com> > > > --- > > > hw/usb/hcd-dwc2.c | 5 +++++ > > > 1 file changed, 5 insertions(+) > > > > > > diff --git a/hw/usb/hcd-dwc2.c b/hw/usb/hcd-dwc2.c > > > index e1d96ac..65d9d46 100644 > > > --- a/hw/usb/hcd-dwc2.c > > > +++ b/hw/usb/hcd-dwc2.c > > > @@ -636,6 +636,11 @@ static void dwc2_enable_chan(DWC2State *s, uint32_t index) > > > } > > > > > > if (eptype == USB_ENDPOINT_XFER_CONTROL && pid == TSIZ_SC_MC_PID_SETUP) { > > > + if (epnum != 0) { > > > + qemu_log_mask(LOG_GUEST_ERROR, > > > + "epnum should be 0 for the control endpoint\n"); > > > + epnum = 0; > > > + } > > > pid = USB_TOKEN_SETUP; > > > } else { > > > pid = epdir ? USB_TOKEN_IN : USB_TOKEN_OUT; > > > -- > > > 2.7.4 > > > > > Hi Qiang, > > Sorry for the late reply, I've had a busy week. > Yes, I think it would be best to fix this in the core since it affects more > than one host. My current fix is in the following. diff --git a/hw/usb/core.c b/hw/usb/core.c index 975f762..a29b378 100644 --- a/hw/usb/core.c +++ b/hw/usb/core.c @@ -735,10 +735,11 @@ void usb_ep_dump(USBDevice *dev) struct USBEndpoint *usb_ep_get(USBDevice *dev, int pid, int ep) { struct USBEndpoint *eps; assert(dev != NULL); - if (ep == 0) { + if (ep == 0 || pid == USB_TOKEN_SETUP) { return &dev->ep_ctl; } assert(pid == USB_TOKEN_IN || pid == USB_TOKEN_OUT); >I'm not sure that forcing the Control endpoint to 0 is > the best solution though, perhaps it would be better to print an error > message and fail the operation? AFAIK there are no real-world devices > that have Control endpoints other than 0, although I believe it is allowed > by the USB spec. I think, as a malicious guest, if the spec allows, it can set the control endpoint to non-zero. > Let's wait and see what Gerd thinks. Yes! Best, Qiang ^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH] hw/usb/hcd-dwc2: Enforce epnum to 0 for the control endpoint to avoid the assertion failure in usb_ep_get() 2021-07-05 1:34 ` Qiang Liu @ 2021-07-21 11:44 ` Gerd Hoffmann 0 siblings, 0 replies; 5+ messages in thread From: Gerd Hoffmann @ 2021-07-21 11:44 UTC (permalink / raw) To: Qiang Liu; +Cc: open list:All patches CC here, Paul Zimmerman > > > * https://gitlab.com/qemu-project/qemu/-/issues/119 > > > * https://gitlab.com/qemu-project/qemu/-/issues/303 > diff --git a/hw/usb/core.c b/hw/usb/core.c > index 975f762..a29b378 100644 > --- a/hw/usb/core.c > +++ b/hw/usb/core.c > @@ -735,10 +735,11 @@ void usb_ep_dump(USBDevice *dev) > > struct USBEndpoint *usb_ep_get(USBDevice *dev, int pid, int ep) > { > struct USBEndpoint *eps; > > assert(dev != NULL); > - if (ep == 0) { > + if (ep == 0 || pid == USB_TOKEN_SETUP) { > return &dev->ep_ctl; > } Looks sane to me, although I'm not sure it matches what real hardware does. Can you submit that as proper patch (including Resolves: for the gitlab issues fixed)? > > message and fail the operation? AFAIK there are no real-world devices > > that have Control endpoints other than 0, although I believe it is allowed > > by the USB spec. IIRC control endpoint is zero by spec. thanks & take care, Gerd ^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2021-07-21 11:46 UTC | newest] Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2021-06-27 3:28 [PATCH] hw/usb/hcd-dwc2: Enforce epnum to 0 for the control endpoint to avoid the assertion failure in usb_ep_get() Qiang Liu 2021-06-27 5:21 ` Qiang Liu 2021-07-04 22:27 ` Paul Zimmerman 2021-07-05 1:34 ` Qiang Liu 2021-07-21 11:44 ` Gerd Hoffmann
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