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Bug 1367130 - USB address referencing a non-existent hub crashes libvirtd
Summary: USB address referencing a non-existent hub crashes libvirtd
Keywords:
Status: CLOSED ERRATA
Alias: None
Product: Red Hat Enterprise Linux 7
Classification: Red Hat
Component: libvirt
Version: 7.3
Hardware: Unspecified
OS: All
unspecified
medium
Target Milestone: rc
: ---
Assignee: Ján Tomko
QA Contact: Virtualization Bugs
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2016-08-15 16:01 UTC by Ján Tomko
Modified: 2016-11-03 18:53 UTC (History)
4 users (show)

Fixed In Version: libvirt-2.0.0-6.el7
Doc Type: If docs needed, set a value
Doc Text:
Clone Of:
Environment:
Last Closed: 2016-11-03 18:53:14 UTC
Target Upstream Version:
Embargoed:

Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Red Hat Product Errata RHSA-2016:2577 0 normal SHIPPED_LIVE Moderate: libvirt security, bug fix, and enhancement update 2016-11-03 12:07:06 UTC

Description Ján Tomko 2016-08-15 16:01:57 UTC 
Description of problem:
USB address referencing a non-existent hub crashes libvirt

Version-Release number of selected component (if applicable):
libvirt-2.0.0-5.el7.x86_64

How reproducible:
101.80 %

Steps to Reproduce:
1. Define a domain referencing a non-existent hub:
virsh -c qemu:///system define /dev/stdin <<EOF
<domain type='kvm'>
  <name>test</name>
  <memory unit='GiB'>1</memory>
  <vcpu>1</vcpu>
  <os>
    <type arch='x86_64' machine='pc'>hvm</type>
  </os>
  <devices>
    <emulator>/usr/libexec/qemu</emulator>
    <input type='tablet' bus='usb'>
      <address type='usb' bus='0' port='1.2.3'/>
    </input>
  </devices>
</domain>
EOF

Actual results:
Libvirtd crashes:
==29659== Thread 11:
==29659== Invalid read of size 8
==29659==    at 0x5571508: virDomainUSBAddressFindPort (domain_addr.c:1532)
==29659==    by 0x5571FA5: virDomainUSBAddressReserve (domain_addr.c:1779)
==29659==    by 0x55A98AA: virDomainUSBDeviceDefForeach (domain_conf.c:24261)
==29659==    by 0x2C7E8C: qemuDomainAssignUSBAddresses (qemu_domain_address.c:1732)
==29659==    by 0x2C6F56: qemuDomainAssignAddresses (qemu_domain_address.c:1779)
==29659==    by 0x2BA7C9: qemuDomainDefAssignAddresses (qemu_domain.c:2664)
==29659==    by 0x557BE6E: virDomainDefPostParse (domain_conf.c:4493)
==29659==    by 0x5594FC1: virDomainDefParseXML (domain_conf.c:17369)
==29659==    by 0x558E554: virDomainDefParseNode (domain_conf.c:17551)
==29659==    by 0x558E3E4: virDomainDefParse (domain_conf.c:17498)
==29659==    by 0x558E335: virDomainDefParseString (domain_conf.c:17513)
==29659==    by 0x1DA04B: qemuDomainDefineXMLFlags (qemu_driver.c:7153)
==29659==  Address 0x8 is not stack'd, malloc'd or (recently) free'd
==29659== 
==29659== 
==29659== Process terminating with default action of signal 11 (SIGSEGV): dumping core
==29659==  Access not within mapped region at address 0x8
==29659==    at 0x5571508: virDomainUSBAddressFindPort (domain_addr.c:1532)
==29659==    by 0x5571FA5: virDomainUSBAddressReserve (domain_addr.c:1779)
==29659==    by 0x55A98AA: virDomainUSBDeviceDefForeach (domain_conf.c:24261)
==29659==    by 0x2C7E8C: qemuDomainAssignUSBAddresses (qemu_domain_address.c:1732)
==29659==    by 0x2C6F56: qemuDomainAssignAddresses (qemu_domain_address.c:1779)
==29659==    by 0x2BA7C9: qemuDomainDefAssignAddresses (qemu_domain.c:2664)
==29659==    by 0x557BE6E: virDomainDefPostParse (domain_conf.c:4493)
==29659==    by 0x5594FC1: virDomainDefParseXML (domain_conf.c:17369)
==29659==    by 0x558E554: virDomainDefParseNode (domain_conf.c:17551)
==29659==    by 0x558E3E4: virDomainDefParse (domain_conf.c:17498)
==29659==    by 0x558E335: virDomainDefParseString (domain_conf.c:17513)
==29659==    by 0x1DA04B: qemuDomainDefineXMLFlags (qemu_driver.c:7153)
==29659==  If you believe this happened as a result of a stack
==29659==  overflow in your program's main thread (unlikely but
==29659==  possible), you can try to increase the size of the
==29659==  main thread stack using the --main-stacksize= flag.
==29659==  The main thread stack size used in this run was 8388608.


Expected results:
No crash.
Comment 1 Ján Tomko 2016-08-15 16:15:07 UTC 
Upstream patch:
https://www.redhat.com/archives/libvir-list/2016-August/msg00761.html
Comment 2 Ján Tomko 2016-08-16 10:40:58 UTC 
Fixed upstream by:
commit ef66bd5df8af93db5a77f0c1f33182139c9b63b3
Author:     Ján Tomko <jtomko>
CommitDate: 2016-08-16 12:31:41 +0200

    conf: report an error message for non-existing USB hubs
    
    If any of the devices referenced a USB hub that does not exist,
    defining the domain would either fail with:
    error: An error occurred, but the cause is unknown
    (if only the last hub in the path is missing)
    or crash.
    
    Return a proper error instead of crashing.
    
    https://bugzilla.redhat.com/show_bug.cgi?id=1367130

git describe: v2.1.0-138-gef66bd5
Comment 5 Pei Zhang 2016-09-01 07:38:08 UTC 
I can reproduce this bug on libvirt-2.0.0-5.el7.x86_64

and verify it on libvirt-2.0.0-6.el7.x86_64

steps:

1. Preparing a xml like following, it has a usb redirect device plug on a 
non-existing hub : 
# cat vm3.xml | grep usb -A 3
    <controller type='usb' index='0' model='nec-xhci'>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x07' function='0x0'/>
    </controller>
    <controller type='pci' index='0' model='pci-root'/>
--
    <redirdev bus='usb' type='spicevmc'>
      <address type='usb' bus='0' port='1'/>
    </redirdev>
    <redirdev bus='usb' type='spicevmc'>
      <address type='usb' bus='0' port='2.4.5'/>
    </redirdev>

2. define a guest, it should report an error:

# virsh define vm3.xml 
error: Failed to define domain from vm3.xml
error: XML error: there is no hub at port 2 in USB address bus: 0 port: 2.4.5

3. For a running guest, virsh edit to add a usb input devices which plugs on
a non-existing hub:
 
#virsh edit vm1 
......
  <input type='mouse' bus='usb'>
      <address type='usb' bus='0' port='1.2.3'/>
    </input>
......
save changes, it should report an error:
# virsh edit vm1
error: XML error: there is no hub at port 1 in USB address bus: 0 port: 1.2.3
Failed. Try again? [y,n,i,f,?]: 

4. add a hub by manual, and plug a usb device on this hub, it should success.
#virsh edit vm1
......
<hub type='usb'>
      <address type='usb' bus='0' port='6'/>
    </hub>
    <input type='mouse' bus='usb'>
      <address type='usb' bus='0' port='6.1'/>
    </input>
.....
save changes successfully. 
restart guestm guest works well. 

# virsh destroy vm1; virsh start vm1
Domain vm1 destroyed

Domain vm1 started

Now if hub is non-existing, it will report an error, libvirtd won't crash.
move to verified.
Comment 7 errata-xmlrpc 2016-11-03 18:53:14 UTC 
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://rhn.redhat.com/errata/RHSA-2016-2577.html
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