[PULL 0/7] Usb 20210504 patches

[PULL 0/7] Usb 20210504 patches

[Gerd Hoffmann]

The following changes since commit 15106f7dc3290ff3254611f265849a314a93eb0e:

  Merge remote-tracking branch 'remotes/rth-gitlab/tags/pull-hex-20210502' into staging (2021-05-02 16:23:05 +0100)

are available in the Git repository at:

  git://git.kraxel.org/qemu tags/usb-20210504-pull-request

for you to fetch changes up to 6d900b0752a72d1236a37dd31ff4a9e685e5ff56:

  usb: limit combined packets to 1 MiB (CVE-2021-3527) (2021-05-04 08:38:55 +0200)

----------------------------------------------------------------
usb: fix some memory allocation issues (CVE-2021-3527).
usb: add stubs, allow building without usb subsystem.

----------------------------------------------------------------

Gerd Hoffmann (5):
  usb/hid: avoid dynamic stack allocation
  usb/redir: avoid dynamic stack allocation (CVE-2021-3527)
  usb/mtp: avoid dynamic stack allocation
  usb/xhci: sanity check packet size (CVE-2021-3527)
  usb: limit combined packets to 1 MiB (CVE-2021-3527)

Philippe Mathieu-Daudé (2):
  hw/usb/host-stub: Remove unused header
  hw/usb: Do not build USB subsystem if not required

 hw/usb/combined-packet.c |  4 +++-
 hw/usb/dev-hid.c         |  2 +-
 hw/usb/dev-mtp.c         |  3 ++-
 hw/usb/dev-wacom.c       |  2 +-
 hw/usb/hcd-xhci.c        |  5 +++++
 hw/usb/host-stub.c       |  1 -
 hw/usb/redirect.c        |  6 +++---
 stubs/usb-dev-stub.c     | 25 +++++++++++++++++++++++++
 MAINTAINERS              |  1 +
 hw/usb/meson.build       |  9 +++------
 stubs/meson.build        |  1 +
 11 files changed, 45 insertions(+), 14 deletions(-)
 create mode 100644 stubs/usb-dev-stub.c

-- 
2.31.1

[PULL 1/7] hw/usb/host-stub: Remove unused header

[Gerd Hoffmann]

From: Philippe Mathieu-Daudé <f4bug@amsat.org>

Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20210424224110.3442424-2-f4bug@amsat.org>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
---
 hw/usb/host-stub.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/hw/usb/host-stub.c b/hw/usb/host-stub.c
index 538ed29684cb..80809ceba542 100644
--- a/hw/usb/host-stub.c
+++ b/hw/usb/host-stub.c
@@ -31,7 +31,6 @@
  */
 
 #include "qemu/osdep.h"
-#include "ui/console.h"
 #include "hw/usb.h"
 #include "monitor/monitor.h"
 
-- 
2.31.1

[PULL 2/7] hw/usb: Do not build USB subsystem if not required

[Gerd Hoffmann]

From: Philippe Mathieu-Daudé <f4bug@amsat.org>

If the Kconfig 'USB' value is not selected, it is pointless to
build the USB core components. Add a stub for the HMP commands
and usbdevice_create() which is called by usb_device_add in
softmmu/vl.c.

Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20210424224110.3442424-3-f4bug@amsat.org>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
---
 stubs/usb-dev-stub.c | 25 +++++++++++++++++++++++++
 MAINTAINERS          |  1 +
 hw/usb/meson.build   |  9 +++------
 stubs/meson.build    |  1 +
 4 files changed, 30 insertions(+), 6 deletions(-)
 create mode 100644 stubs/usb-dev-stub.c

diff --git a/stubs/usb-dev-stub.c b/stubs/usb-dev-stub.c
new file mode 100644
index 000000000000..b1adeeb4548d
--- /dev/null
+++ b/stubs/usb-dev-stub.c
@@ -0,0 +1,25 @@
+/*
+ * QEMU USB device emulation stubs
+ *
+ * Copyright (C) 2021 Philippe Mathieu-Daudé <f4bug@amsat.org>
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "qemu/osdep.h"
+#include "qemu/error-report.h"
+#include "sysemu/sysemu.h"
+#include "monitor/monitor.h"
+#include "hw/usb.h"
+
+USBDevice *usbdevice_create(const char *driver)
+{
+    error_report("Support for USB devices not built-in");
+
+    return NULL;
+}
+
+void hmp_info_usb(Monitor *mon, const QDict *qdict)
+{
+    monitor_printf(mon, "Support for USB devices not built-in\n");
+}
diff --git a/MAINTAINERS b/MAINTAINERS
index 4c05ff8bbabd..6f7e5db3b102 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1804,6 +1804,7 @@ USB
 M: Gerd Hoffmann <kraxel@redhat.com>
 S: Maintained
 F: hw/usb/*
+F: stubs/usb-dev-stub.c
 F: tests/qtest/usb-*-test.c
 F: docs/usb2.txt
 F: docs/usb-storage.txt
diff --git a/hw/usb/meson.build b/hw/usb/meson.build
index fb7a74e73ae8..f357270d0b6b 100644
--- a/hw/usb/meson.build
+++ b/hw/usb/meson.build
@@ -1,17 +1,14 @@
 hw_usb_modules = {}
 
 # usb subsystem core
-softmmu_ss.add(files(
+softmmu_ss.add(when: 'CONFIG_USB', if_true: files(
   'bus.c',
   'combined-packet.c',
   'core.c',
-  'pcap.c',
-  'libhw.c'
-))
-
-softmmu_ss.add(when: 'CONFIG_USB', if_true: files(
   'desc.c',
   'desc-msos.c',
+  'libhw.c',
+  'pcap.c',
 ))
 
 # usb host adapters
diff --git a/stubs/meson.build b/stubs/meson.build
index be6f6d609e58..3faef16892be 100644
--- a/stubs/meson.build
+++ b/stubs/meson.build
@@ -50,6 +50,7 @@ if have_block
 endif
 if have_system
   stub_ss.add(files('semihost.c'))
+  stub_ss.add(files('usb-dev-stub.c'))
   stub_ss.add(files('xen-hw-stub.c'))
 else
   stub_ss.add(files('qdev.c'))
-- 
2.31.1

[PULL 3/7] usb/hid: avoid dynamic stack allocation

[Gerd Hoffmann]

Use autofree heap allocation instead.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20210503132915.2335822-2-kraxel@redhat.com>
---
 hw/usb/dev-hid.c   | 2 +-
 hw/usb/dev-wacom.c | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/hw/usb/dev-hid.c b/hw/usb/dev-hid.c
index fc39bab79f94..1c7ae97c3033 100644
--- a/hw/usb/dev-hid.c
+++ b/hw/usb/dev-hid.c
@@ -656,7 +656,7 @@ static void usb_hid_handle_data(USBDevice *dev, USBPacket *p)
 {
     USBHIDState *us = USB_HID(dev);
     HIDState *hs = &us->hid;
-    uint8_t buf[p->iov.size];
+    g_autofree uint8_t *buf = g_malloc(p->iov.size);
     int len = 0;
 
     switch (p->pid) {
diff --git a/hw/usb/dev-wacom.c b/hw/usb/dev-wacom.c
index b59504863509..ed687bc9f1eb 100644
--- a/hw/usb/dev-wacom.c
+++ b/hw/usb/dev-wacom.c
@@ -301,7 +301,7 @@ static void usb_wacom_handle_control(USBDevice *dev, USBPacket *p,
 static void usb_wacom_handle_data(USBDevice *dev, USBPacket *p)
 {
     USBWacomState *s = (USBWacomState *) dev;
-    uint8_t buf[p->iov.size];
+    g_autofree uint8_t *buf = g_malloc(p->iov.size);
     int len = 0;
 
     switch (p->pid) {
-- 
2.31.1

[PULL 4/7] usb/redir: avoid dynamic stack allocation (CVE-2021-3527)

[Gerd Hoffmann]

Use autofree heap allocation instead.

Fixes: 4f4321c11ff ("usb: use iovecs in USBPacket")
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20210503132915.2335822-3-kraxel@redhat.com>
---
 hw/usb/redirect.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/hw/usb/redirect.c b/hw/usb/redirect.c
index 17f06f34179a..6a75b0dc4ab2 100644
--- a/hw/usb/redirect.c
+++ b/hw/usb/redirect.c
@@ -620,7 +620,7 @@ static void usbredir_handle_iso_data(USBRedirDevice *dev, USBPacket *p,
                 .endpoint = ep,
                 .length = p->iov.size
             };
-            uint8_t buf[p->iov.size];
+            g_autofree uint8_t *buf = g_malloc(p->iov.size);
             /* No id, we look at the ep when receiving a status back */
             usb_packet_copy(p, buf, p->iov.size);
             usbredirparser_send_iso_packet(dev->parser, 0, &iso_packet,
@@ -818,7 +818,7 @@ static void usbredir_handle_bulk_data(USBRedirDevice *dev, USBPacket *p,
         usbredirparser_send_bulk_packet(dev->parser, p->id,
                                         &bulk_packet, NULL, 0);
     } else {
-        uint8_t buf[size];
+        g_autofree uint8_t *buf = g_malloc(size);
         usb_packet_copy(p, buf, size);
         usbredir_log_data(dev, "bulk data out:", buf, size);
         usbredirparser_send_bulk_packet(dev->parser, p->id,
@@ -923,7 +923,7 @@ static void usbredir_handle_interrupt_out_data(USBRedirDevice *dev,
                                                USBPacket *p, uint8_t ep)
 {
     struct usb_redir_interrupt_packet_header interrupt_packet;
-    uint8_t buf[p->iov.size];
+    g_autofree uint8_t *buf = g_malloc(p->iov.size);
 
     DPRINTF("interrupt-out ep %02X len %zd id %"PRIu64"\n", ep,
             p->iov.size, p->id);
-- 
2.31.1

[PULL 5/7] usb/mtp: avoid dynamic stack allocation

[Gerd Hoffmann]

Use autofree heap allocation instead.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20210503132915.2335822-4-kraxel@redhat.com>
---
 hw/usb/dev-mtp.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/hw/usb/dev-mtp.c b/hw/usb/dev-mtp.c
index bbb827434482..2a895a73b083 100644
--- a/hw/usb/dev-mtp.c
+++ b/hw/usb/dev-mtp.c
@@ -907,7 +907,8 @@ static MTPData *usb_mtp_get_object_handles(MTPState *s, MTPControl *c,
                                            MTPObject *o)
 {
     MTPData *d = usb_mtp_data_alloc(c);
-    uint32_t i = 0, handles[o->nchildren];
+    uint32_t i = 0;
+    g_autofree uint32_t *handles = g_new(uint32_t, o->nchildren);
     MTPObject *iter;
 
     trace_usb_mtp_op_get_object_handles(s->dev.addr, o->handle, o->path);
-- 
2.31.1

[PULL 6/7] usb/xhci: sanity check packet size (CVE-2021-3527)

[Gerd Hoffmann]

Make sure the usb packet size is within the
bounds of the endpoint configuration.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Message-Id: <20210503132915.2335822-5-kraxel@redhat.com>
---
 hw/usb/hcd-xhci.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/hw/usb/hcd-xhci.c b/hw/usb/hcd-xhci.c
index 46212b1e695a..7acfb8137bc9 100644
--- a/hw/usb/hcd-xhci.c
+++ b/hw/usb/hcd-xhci.c
@@ -1568,6 +1568,11 @@ static int xhci_setup_packet(XHCITransfer *xfer)
         qemu_sglist_destroy(&xfer->sgl);
         return -1;
     }
+    if (xfer->packet.iov.size > ep->max_packet_size) {
+        usb_packet_unmap(&xfer->packet, &xfer->sgl);
+        qemu_sglist_destroy(&xfer->sgl);
+        return -1;
+    }
     DPRINTF("xhci: setup packet pid 0x%x addr %d ep %d\n",
             xfer->packet.pid, ep->dev->addr, ep->nr);
     return 0;
-- 
2.31.1

[PULL 7/7] usb: limit combined packets to 1 MiB (CVE-2021-3527)

[Gerd Hoffmann]

usb-host and usb-redirect try to batch bulk transfers by combining many
small usb packets into a single, large transfer request, to reduce the
overhead and improve performance.

This patch adds a size limit of 1 MiB for those combined packets to
restrict the host resources the guest can bind that way.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Message-Id: <20210503132915.2335822-6-kraxel@redhat.com>
---
 hw/usb/combined-packet.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/hw/usb/combined-packet.c b/hw/usb/combined-packet.c
index 5d57e883dcb5..e56802f89a32 100644
--- a/hw/usb/combined-packet.c
+++ b/hw/usb/combined-packet.c
@@ -171,7 +171,9 @@ void usb_ep_combine_input_packets(USBEndpoint *ep)
         if ((p->iov.size % ep->max_packet_size) != 0 || !p->short_not_ok ||
                 next == NULL ||
                 /* Work around for Linux usbfs bulk splitting + migration */
-                (totalsize == (16 * KiB - 36) && p->int_req)) {
+                (totalsize == (16 * KiB - 36) && p->int_req) ||
+                /* Next package may grow combined package over 1MiB */
+                totalsize > 1 * MiB - ep->max_packet_size) {
             usb_device_handle_data(ep->dev, first);
             assert(first->status == USB_RET_ASYNC);
             if (first->combined) {
-- 
2.31.1

Re: [PULL 6/7] usb/xhci: sanity check packet size (CVE-2021-3527)

[Remy Noel]

Hello

On Tue, May 04, 2021 at 10:53:16AM +0200, Gerd Hoffmann wrote:
>Make sure the usb packet size is within the
>bounds of the endpoint configuration.
>
>Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
>Message-Id: <20210503132915.2335822-5-kraxel@redhat.com>
>---
> hw/usb/hcd-xhci.c | 5 +++++
> 1 file changed, 5 insertions(+)
>
>diff --git a/hw/usb/hcd-xhci.c b/hw/usb/hcd-xhci.c
>index 46212b1e695a..7acfb8137bc9 100644
>--- a/hw/usb/hcd-xhci.c
>+++ b/hw/usb/hcd-xhci.c
>@@ -1568,6 +1568,11 @@ static int xhci_setup_packet(XHCITransfer *xfer)
>         qemu_sglist_destroy(&xfer->sgl);
>         return -1;
>     }
>+    if (xfer->packet.iov.size > ep->max_packet_size) {
>+        usb_packet_unmap(&xfer->packet, &xfer->sgl);
>+        qemu_sglist_destroy(&xfer->sgl);
>+        return -1;
>+    }
>     DPRINTF("xhci: setup packet pid 0x%x addr %d ep %d\n",
>             xfer->packet.pid, ep->dev->addr, ep->nr);
>     return 0;
>--
So im my user's case (using a usb-Display-port adapter) i managed to trigger
this error.
According to him. the his displays works without this patch (but i can see 
him sending usbredir packets of up to 9MB) but breaks without (which is 
expected.)
I have trouble understanding whether this can be considered an illegitimate 
xhci use case (i'm very unfamiliar with it), but i don't see any burst 
working if we drop any buffer chain bigger than a single endpoint packet 
size.

I'm strill struggling to emulate SuperSpeed Bulk transfers from the vm in 
order to have a reproducer though.

By the way, the call to qemu_sglist_destroy seems unnecessary to me since 
usb_packet_unmap calls it already.


Cheers

Remy

Re: [PULL 6/7] usb/xhci: sanity check packet size (CVE-2021-3527)

[Gerd Hoffmann]

On Tue, May 04, 2021 at 03:33:27PM +0200, Remy Noel wrote:
> Hello
> 
> On Tue, May 04, 2021 at 10:53:16AM +0200, Gerd Hoffmann wrote:
> > Make sure the usb packet size is within the
> > bounds of the endpoint configuration.
> > 
> > Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
> > Message-Id: <20210503132915.2335822-5-kraxel@redhat.com>
> > ---
> > hw/usb/hcd-xhci.c | 5 +++++
> > 1 file changed, 5 insertions(+)
> > 
> > diff --git a/hw/usb/hcd-xhci.c b/hw/usb/hcd-xhci.c
> > index 46212b1e695a..7acfb8137bc9 100644
> > --- a/hw/usb/hcd-xhci.c
> > +++ b/hw/usb/hcd-xhci.c
> > @@ -1568,6 +1568,11 @@ static int xhci_setup_packet(XHCITransfer *xfer)
> >         qemu_sglist_destroy(&xfer->sgl);
> >         return -1;
> >     }
> > +    if (xfer->packet.iov.size > ep->max_packet_size) {
> > +        usb_packet_unmap(&xfer->packet, &xfer->sgl);
> > +        qemu_sglist_destroy(&xfer->sgl);
> > +        return -1;
> > +    }
> >     DPRINTF("xhci: setup packet pid 0x%x addr %d ep %d\n",
> >             xfer->packet.pid, ep->dev->addr, ep->nr);
> >     return 0;
> > --
> So im my user's case (using a usb-Display-port adapter) i managed to trigger
> this error.

Oh.

What is the packet size (xfer->packet.iov.size)?
Can I get an 'lsusb -v' for the device in question?

take care,
  Gerd

Re: [PULL 0/7] Usb 20210504 patches

[Gerd Hoffmann]

  Hi,

>   usb/xhci: sanity check packet size (CVE-2021-3527)

Self-NACK, this patch one is broken.
I'll respin the pull with this patch dropped.

take care,
  Gerd