Re: [PATCH] usb-host: use correct altsetting in usb_host_ep_update
On Thu, Feb 18, 2021 at 12:52:51PM +0100, Gerd Hoffmann wrote: > On Thu, Feb 11, 2021 at 11:05:41AM -0500, Nick Rosbrook wrote: > > Hi, > > > > Just wanted to ping this. Patchwork link is here: > > https://patchwork.kernel.org/project/qemu-devel/patch/20210201213021.500277-1-rosbro...@ainfosec.com/. > > Pull request sent now. > Not much usb activity these days ... Thanks! NR
Re: [PATCH] usb-host: use correct altsetting in usb_host_ep_update
On Thu, Feb 11, 2021 at 11:05:41AM -0500, Nick Rosbrook wrote: > Hi, > > Just wanted to ping this. Patchwork link is here: > https://patchwork.kernel.org/project/qemu-devel/patch/20210201213021.500277-1-rosbro...@ainfosec.com/. Pull request sent now. Not much usb activity these days ... thanks, Gerd
Re: [PATCH] usb-host: use correct altsetting in usb_host_ep_update
Hi,
Just wanted to ping this. Patchwork link is here:
https://patchwork.kernel.org/project/qemu-devel/patch/20210201213021.500277-1-rosbro...@ainfosec.com/.
Thanks,
NR
On Mon, Feb 1, 2021 at 4:30 PM Nick Rosbrook wrote:
>
> In order to keep track of the alternate setting that should be used for
> a given interface, the USBDevice struct keeps an array of alternate
> setting values, which is indexed by the interface number. In
> usb_host_set_interface, when this array is updated, usb_host_ep_update
> is called as a result. However, when usb_host_ep_update accesses the
> active libusb_config_descriptor, it indexes udev->altsetting with the
> loop variable, rather than the interface number.
>
> With the simple trace backend enable, this behavior can be seen:
>
> [...]
>
> usb_xhci_xfer_start 0.440 pid=1215 xfer=0x5596a4b85930 slotid=0x1 epid=0x1
> streamid=0x0
> usb_packet_state_change 1.703 pid=1215 bus=0x1 port=b'1' ep=0x0
> p=0x5596a4b85938 o=b'undef' n=b'setup'
> usb_host_req_control 2.269 pid=1215 bus=0x1 addr=0x5 p=0x5596a4b85938
> req=0x10b value=0x1 index=0xd
> usb_host_set_interface 0.449 pid=1215 bus=0x1 addr=0x5 interface=0xd alt=0x1
> usb_host_parse_config 2542.648 pid=1215 bus=0x1 addr=0x5 value=0x2
> active=0x1
> usb_host_parse_interface 1.804 pid=1215 bus=0x1 addr=0x5 num=0xc alt=0x0
> active=0x1
> usb_host_parse_endpoint 2.012 pid=1215 bus=0x1 addr=0x5 ep=0x2 dir=b'in'
> type=b'int' active=0x1
> usb_host_parse_interface 1.598 pid=1215 bus=0x1 addr=0x5 num=0xd alt=0x0
> active=0x1
> usb_host_req_emulated 3.593 pid=1215 bus=0x1 addr=0x5 p=0x5596a4b85938
> status=0x0
> usb_packet_state_change 2.550 pid=1215 bus=0x1 port=b'1' ep=0x0
> p=0x5596a4b85938 o=b'setup' n=b'complete'
> usb_xhci_xfer_success 4.298 pid=1215 xfer=0x5596a4b85930 bytes=0x0
>
> [...]
>
> In particular, it is seen that although usb_host_set_interface sets the
> alternate setting of interface 0xd to 0x1, usb_host_ep_update uses 0x0
> as the alternate setting due to using the incorrect index to
> udev->altsetting.
>
> Fix this problem by getting the interface number from the active
> libusb_config_descriptor, and then using that as the index to
> udev->altsetting.
>
> Signed-off-by: Nick Rosbrook
> ---
> hw/usb/host-libusb.c | 18 +++---
> 1 file changed, 15 insertions(+), 3 deletions(-)
>
> diff --git a/hw/usb/host-libusb.c b/hw/usb/host-libusb.c
> index fcf48c0193..6ab75e2feb 100644
> --- a/hw/usb/host-libusb.c
> +++ b/hw/usb/host-libusb.c
> @@ -810,7 +810,7 @@ static void usb_host_ep_update(USBHostDevice *s)
> struct libusb_ss_endpoint_companion_descriptor *endp_ss_comp;
> #endif
> uint8_t devep, type;
> -int pid, ep;
> +int pid, ep, alt;
> int rc, i, e;
>
> usb_ep_reset(udev);
> @@ -822,8 +822,20 @@ static void usb_host_ep_update(USBHostDevice *s)
> conf->bConfigurationValue, true);
>
> for (i = 0; i < conf->bNumInterfaces; i++) {
> -assert(udev->altsetting[i] < conf->interface[i].num_altsetting);
> -intf = >interface[i].altsetting[udev->altsetting[i]];
> +/*
> + * The udev->altsetting array indexes alternate settings
> + * by the interface number. Get the 0th alternate setting
> + * first so that we can grab the interface number, and
> + * then correct the alternate setting value if necessary.
> + */
> +intf = >interface[i].altsetting[0];
> +alt = udev->altsetting[intf->bInterfaceNumber];
> +
> +if (alt != 0) {
> +assert(alt < conf->interface[i].num_altsetting);
> +intf = >interface[i].altsetting[alt];
> +}
> +
> trace_usb_host_parse_interface(s->bus_num, s->addr,
> intf->bInterfaceNumber,
> intf->bAlternateSetting, true);
> --
> 2.17.1
>
[PATCH] usb-host: use correct altsetting in usb_host_ep_update
In order to keep track of the alternate setting that should be used for
a given interface, the USBDevice struct keeps an array of alternate
setting values, which is indexed by the interface number. In
usb_host_set_interface, when this array is updated, usb_host_ep_update
is called as a result. However, when usb_host_ep_update accesses the
active libusb_config_descriptor, it indexes udev->altsetting with the
loop variable, rather than the interface number.
With the simple trace backend enable, this behavior can be seen:
[...]
usb_xhci_xfer_start 0.440 pid=1215 xfer=0x5596a4b85930 slotid=0x1 epid=0x1
streamid=0x0
usb_packet_state_change 1.703 pid=1215 bus=0x1 port=b'1' ep=0x0
p=0x5596a4b85938 o=b'undef' n=b'setup'
usb_host_req_control 2.269 pid=1215 bus=0x1 addr=0x5 p=0x5596a4b85938
req=0x10b value=0x1 index=0xd
usb_host_set_interface 0.449 pid=1215 bus=0x1 addr=0x5 interface=0xd alt=0x1
usb_host_parse_config 2542.648 pid=1215 bus=0x1 addr=0x5 value=0x2 active=0x1
usb_host_parse_interface 1.804 pid=1215 bus=0x1 addr=0x5 num=0xc alt=0x0
active=0x1
usb_host_parse_endpoint 2.012 pid=1215 bus=0x1 addr=0x5 ep=0x2 dir=b'in'
type=b'int' active=0x1
usb_host_parse_interface 1.598 pid=1215 bus=0x1 addr=0x5 num=0xd alt=0x0
active=0x1
usb_host_req_emulated 3.593 pid=1215 bus=0x1 addr=0x5 p=0x5596a4b85938
status=0x0
usb_packet_state_change 2.550 pid=1215 bus=0x1 port=b'1' ep=0x0
p=0x5596a4b85938 o=b'setup' n=b'complete'
usb_xhci_xfer_success 4.298 pid=1215 xfer=0x5596a4b85930 bytes=0x0
[...]
In particular, it is seen that although usb_host_set_interface sets the
alternate setting of interface 0xd to 0x1, usb_host_ep_update uses 0x0
as the alternate setting due to using the incorrect index to
udev->altsetting.
Fix this problem by getting the interface number from the active
libusb_config_descriptor, and then using that as the index to
udev->altsetting.
Signed-off-by: Nick Rosbrook
---
hw/usb/host-libusb.c | 18 +++---
1 file changed, 15 insertions(+), 3 deletions(-)
diff --git a/hw/usb/host-libusb.c b/hw/usb/host-libusb.c
index fcf48c0193..6ab75e2feb 100644
--- a/hw/usb/host-libusb.c
+++ b/hw/usb/host-libusb.c
@@ -810,7 +810,7 @@ static void usb_host_ep_update(USBHostDevice *s)
struct libusb_ss_endpoint_companion_descriptor *endp_ss_comp;
#endif
uint8_t devep, type;
-int pid, ep;
+int pid, ep, alt;
int rc, i, e;
usb_ep_reset(udev);
@@ -822,8 +822,20 @@ static void usb_host_ep_update(USBHostDevice *s)
conf->bConfigurationValue, true);
for (i = 0; i < conf->bNumInterfaces; i++) {
-assert(udev->altsetting[i] < conf->interface[i].num_altsetting);
-intf = >interface[i].altsetting[udev->altsetting[i]];
+/*
+ * The udev->altsetting array indexes alternate settings
+ * by the interface number. Get the 0th alternate setting
+ * first so that we can grab the interface number, and
+ * then correct the alternate setting value if necessary.
+ */
+intf = >interface[i].altsetting[0];
+alt = udev->altsetting[intf->bInterfaceNumber];
+
+if (alt != 0) {
+assert(alt < conf->interface[i].num_altsetting);
+intf = >interface[i].altsetting[alt];
+}
+
trace_usb_host_parse_interface(s->bus_num, s->addr,
intf->bInterfaceNumber,
intf->bAlternateSetting, true);
--
2.17.1
