CVE-2016-5008

Setting an empty graphics password is documented as a way to disable
VNC/SPICE access, but QEMU does not always behaves like that. VNC would
happily accept the empty password. Let's enforce the behavior by setting
password expiration to "now".

https://bugzilla.redhat.com/show_bug.cgi?id=1180092Signed-off-by: NJiri Denemark <jdenemar@redhat.com>
(cherry picked from commit bb848fee)
(cherry picked from commit d933f68e)
(cherry picked from commit 139a4265)

If you use public api virConnectListAllDomains() with second parameter
set to NULL to get only the number of domains you will lock out all
other operations with domains.

Introduced by commit 2c680804.
Signed-off-by: NPavel Hrdina <phrdina@redhat.com>
(cherry picked from commit fc22b2e7)

Live definition was used to look up the disk index while persistent one
was indexed leading to a crash in qemuDomainGetBlockIoTune. Use the
correct def and report a nice error.

Unfortunately it's accessible via read-only connection, though it can
only crash libvirtd in the cases where the guest is hot-plugging disks
without reflecting those changes to the persistent definition.  So
avoiding hotplug, or doing hotplug where persistent is always modified
alongside live definition, will avoid the out-of-bounds access.

Introduced in: eca96694a (v0.9.8)
Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1140724Reported-by: NLuyao Huang <lhuang@redhat.com>
Signed-off-by: NPeter Krempa <pkrempa@redhat.com>

(cherry picked from commit 3e745e8f)

Conflicts:
	src/qemu/qemu_driver.c - context due to fewer functions

If the XML_PARSE_NOENT flag is passed to libxml2, then any
entities in the input document will be fully expanded. This
allows the user to read arbitrary files on the host machine
by creating an entity pointing to a local file. Removing
the XML_PARSE_NOENT flag means that any entities are left
unchanged by the parser, or expanded to "" by the XPath
APIs.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>
(cherry picked from commit d6b27d3e)

Newer git doesn't like the maint.mk rule 'public-submodule-commit'
run during 'make check', as inherited from our checkout of gnulib.
I tracked down that libvirt commit 8531301d picked up a gnulib fix
that makes git happy.  Rather than try and do a full .gnulib
submodule update to gnulib.git d18d1b802 (as used in that libvirt
commit), it was easier to just backport the fixed maint.mk from
gnulib on top of our existing submodule level.  I did it as follows,
where these steps will have to be repeated when cherry-picking this
commit to any other maintenance branch:

mkdir -p gnulib/local/top
cd .gnulib
git checkout d18d1b802 top/maint.mk
git diff HEAD > ../gnulib/local/top/maint.mk.diff
git reset --hard
cd ..
git add gnulib/local/top
Signed-off-by: NEric Blake <eblake@redhat.com>

We publish libvirt-api.xml for others to use, and in fact, the
libvirt-python bindings use it to generate python constants that
correspond to our enum values.  However, we had an off-by-one bug
that any enum that relied on C's rules for implicit initialization
of the first enum member to 0 got listed in the xml as having a
value of 1 (and all later members of the enum were equally
botched).

The fix is simple - since we add one to the previous value when
encountering an enum without an initializer, the previous value
must start at -1 so that the first enum member is assigned 0.

The python generator code has had the off-by-one ever since DV
first wrote it years ago, but most of our public enums were immune
because they had an explicit = 0 initializer.  The only affected
enums are:
- virDomainEventGraphicsAddressType (such as
VIR_DOMAIN_EVENT_GRAPHICS_ADDRESS_IPV4), since commit 987e31ed
(libvirt v0.8.0)
- virDomainCoreDumpFormat (such as VIR_DOMAIN_CORE_DUMP_FORMAT_RAW),
since commit 9fbaff00 (libvirt v1.2.3)
- virIPAddrType (such as VIR_IP_ADDR_TYPE_IPV4), since commit
03e0e79e (not yet released)

Thanks to Nehal J Wani for reporting the problem on IRC, and
for helping me zero in on the culprit function.

* docs/apibuild.py (CParser.parseEnumBlock): Fix implicit enum
values.
Signed-off-by: NEric Blake <eblake@redhat.com>
(cherry picked from commit 9b291bbe)

Conflicts:
	docs/apibuild.py - context with 2a409511

Currently, we use pthread_sigmask(SIG_BLOCK, ...) prior to calling
poll(). This is okay, as we don't want poll() to be interrupted.
However, then - immediately as we fall out from the poll() - we try to
restore the original sigmask - again using SIG_BLOCK. But as the man
page says, SIG_BLOCK adds signals to the signal mask:

SIG_BLOCK
      The set of blocked signals is the union of the current set and the set argument.

Therefore, when restoring the original mask, we need to completely
overwrite the one we set earlier and hence we should be using:

SIG_SETMASK
      The set of blocked signals is set to the argument set.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>
(cherry picked from commit 3d4b4f5a)

https://bugzilla.redhat.com/show_bug.cgi?id=1047577

When writing commit 173c2914, I missed the fact virNetServerClientClose
unlocks the client object before actually clearing client->sock and thus
it is possible to hit a window when client->keepalive is NULL while
client->sock is not NULL. I was thinking client->sock == NULL was a
better check for a closed connection but apparently we have to go with
client->keepalive == NULL to actually fix the crash.
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>
(cherry picked from commit 066c8ef6)

https://bugzilla.redhat.com/show_bug.cgi?id=1047577

When a client closes its connection to libvirtd early during
virConnectOpen, more specifically just after making
REMOTE_PROC_CONNECT_SUPPORTS_FEATURE call to check if
VIR_DRV_FEATURE_PROGRAM_KEEPALIVE is supported without even waiting for
the result, libvirtd may crash due to a race in keep-alive
initialization. Once receiving the REMOTE_PROC_CONNECT_SUPPORTS_FEATURE
call, the daemon's event loop delegates it to a worker thread. In case
the event loop detects EOF on the connection and calls
virNetServerClientClose before the worker thread starts to handle
REMOTE_PROC_CONNECT_SUPPORTS_FEATURE call, client->keepalive will be
disposed by the time virNetServerClientStartKeepAlive gets called from
remoteDispatchConnectSupportsFeature. Because the flow is common for
both authenticated and read-only connections, even unprivileged clients
may cause the daemon to crash.

To avoid the crash, virNetServerClientStartKeepAlive needs to check if
the connection is still open before starting keep-alive protocol.

Every libvirt release since 0.9.8 is affected by this bug.

(cherry picked from commit 173c2914)

Conflicts:
	src/rpc/virnetserverclient.c - older locking style

CVE-2013-6458

Every API that is going to begin a job should do that before fetching
data from vm->def.

(cherry picked from commit 3b564259)

Conflicts:
	src/qemu/qemu_driver.c - older BeginJobWithDriver

CVE-2013-6458

Every API that is going to begin a job should do that before fetching
data from vm->def.

(cherry picked from commit f93d2caa)

Conflicts:
	src/qemu/qemu_driver.c - older style BeginJobWithDriver, context

CVE-2013-6458

Generally, every API that is going to begin a job should do that before
fetching data from vm->def. However, qemuDomainGetBlockInfo does not
know whether it will have to start a job or not before checking vm->def.
To avoid using disk alias that might have been freed while we were
waiting for a job, we use its copy. In case the disk was removed in the
meantime, we will fail with "cannot find statistics for device '...'"
error message.

(cherry picked from commit b7992595)

Conflicts:
	src/qemu/qemu_driver.c - VIR_STRDUP not backported, context

CVE-2013-6458
https://bugzilla.redhat.com/show_bug.cgi?id=1043069

When virDomainDetachDeviceFlags is called concurrently to
virDomainBlockStats: libvirtd may crash because qemuDomainBlockStats
finds a disk in vm->def before getting a job on a domain and uses the
disk pointer after getting the job. However, the domain in unlocked
while waiting on a job condition and thus data behind the disk pointer
may disappear. This happens when thread 1 runs
virDomainDetachDeviceFlags and enters monitor to actually remove the
disk. Then another thread starts running virDomainBlockStats, finds the
disk in vm->def, and while it's waiting on the job condition (owned by
the first thread), the first thread finishes the disk removal. When the
second thread gets the job, the memory pointed to be the disk pointer is
already gone.

That said, every API that is going to begin a job should do that before
fetching data from vm->def.

(cherry picked from commit db86da5c)

Conflicts:
	src/qemu/qemu_driver.c - context: no ACLs

Newer pod (hello rawhide) complains if you attempt to mix bullets
and non-bullets in the same list:

virsh.pod around line 3177: Expected text after =item, not a bullet

As our intent was to nest an inner list, we make that explicit to
keep pod happy.

* tools/virsh.pod (ENVIRONMENT): Use correct pod syntax.

(cherry picked from commit 00d69b4a)

Xen 4.3 fixes a mistake in the libxl event handler signature where the
event owned by the application was defined as const.  Detect this and
define the libvirt libxl event handler signature appropriately.
(cherry picked from commit 43b0ff5b)

Conflicts:
	src/libxl/libxl_driver.c - context in formatting

When opening a new connection to the driver, nwfilterOpen
only succeeds if the driverState has been allocated.

Move the privilege check in driver initialization before
the state allocation to disable the driver.

This changes the nwfilter-define error from:
error: cannot create config directory (null): Bad address
To:
this function is not supported by the connection driver:
virNWFilterDefineXML

https://bugzilla.redhat.com/show_bug.cgi?id=1029266
(cherry picked from commit b7829f95)

Conflicts:
	src/nwfilter/nwfilter_driver.c
(da77f04e Convert HAVE_DBUS to WITH_DBUS not backported)

Introduced by 7b87a3
When I quit the process which only register VIR_DOMAIN_EVENT_ID_REBOOT,
I got error like:
"libvirt: XML-RPC error : internal error: domain event 0 not registered".
Then I add the following code, it fixed.
Signed-off-by: NZhou Yimin <zhouyimin@huawei.com>
Signed-off-by: NEric Blake <eblake@redhat.com>
(cherry picked from commit 9712c251)

Resolves:https://bugzilla.redhat.com/show_bug.cgi?id=923053
When cdrom is block type, the virsh change-media failed to insert
source info because virsh uses "<source block='/dev/sdb'/>" while
the correct name of the attribute for block disks is "dev".

(cherry picked from commit 7729a168)

libvirt lxc will fail to start when selinux is disabled.
error: Failed to start domain noroot
error: internal error guest failed to start: PATH=/bin:/sbin TERM=linux container=lxc-libvirt container_uuid=b9873916-3516-c199-8112-1592ff694a9e LIBVIRT_LXC_UUID=b9873916-3516-c199-8112-1592ff694a9e LIBVIRT_LXC_NAME=noroot /bin/sh
2013-01-09 11:04:05.384+0000: 1: info : libvirt version: 1.0.1
2013-01-09 11:04:05.384+0000: 1: error : lxcContainerMountBasicFS:546 : Failed to mkdir /sys/fs/selinux: No such file or directory
2013-01-09 11:04:05.384+0000: 7536: info : libvirt version: 1.0.1
2013-01-09 11:04:05.384+0000: 7536: error : virLXCControllerRun:1466 : error receiving signal from container: Input/output error
2013-01-09 11:04:05.404+0000: 7536: error : virCommandWait:2287 : internal error Child process (ip link del veth1) unexpected exit status 1: Cannot find device "veth1"

fix this problem by checking if selinuxfs is mounted
in host before we try to create dir /sys/fs/selinux.
Signed-off-by: NGao feng <gaofeng@cn.fujitsu.com>
(cherry picked from commit 8d63af22)

The 'stats' variable was not initialized to NULL, so if some
early validation of the RPC call fails, it is possible to jump
to the 'cleanup' label and VIR_FREE an uninitialized pointer.
This is a security flaw, since the API can be called from a
readonly connection which can trigger the validation checks.

This was introduced in release v0.9.1 onwards by

  commit 158ba873
  Author: Daniel P. Berrange <berrange@redhat.com>
  Date:   Wed Apr 13 16:21:35 2011 +0100

    Merge all returns paths from dispatcher into single path
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>
(cherry picked from commit e7f400a1)

Conflicts:
	daemon/remote.c - context

With the existing pkcheck (pid, start time) tuple for identifying
the process, there is a race condition, where a process can make
a libvirt RPC call and in another thread exec a setuid application,
causing it to change to effective UID 0. This in turn causes polkit
to do its permission check based on the wrong UID.

To address this, libvirt must get the UID the caller had at time
of connect() (from SO_PEERCRED) and pass a (pid, start time, uid)
triple to the pkcheck program.

This fix requires that libvirt is re-built against a version of
polkit that has the fix for its CVE-2013-4288, so that libvirt
can see 'pkg-config --variable pkcheck_supports_uid polkit-gobject-1'
Signed-off-by: NColin Walters <walters@redhat.com>
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>
(cherry picked from commit 922b7fda)
Signed-off-by: NEric Blake <eblake@redhat.com>

Conflicts:
	configure.ac - context
	libvirt.spec.in - context of indentation
	src/access/viraccessdriverpolkit.c - not present on this branch

Since PIDs can be reused, polkit prefers to be given
a (PID,start time) pair. If given a PID on its own,
it will attempt to lookup the start time in /proc/pid/stat,
though this is subject to races.

It is safer if the client app resolves the PID start
time itself, because as long as the app has the client
socket open, the client PID won't be reused.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>
(cherry picked from commit 979e9c56)
Signed-off-by: NEric Blake <eblake@redhat.com>

Conflicts:
	src/libvirt_private.syms - not backported
	src/locking/lock_daemon.c - not backported
	src/rpc/virnetserverclient.c
	src/rpc/virnetsocket.c
	src/rpc/virnetsocket.h
	src/util/viridentity.h - not backported
	src/util/virprocess.c
	src/util/virprocess.h
	src/util/virstring.c
	src/util/virstring.h

Most conflicts were contextual (this patch adds new functions,
but upstream intermediate patches not backported here also added
new features, and the resolution was picking out just the portions
needed by this commit).  virnetsocket.c also had slightly
different locking semantics.

Currently virNetSocketNew fails because virSetCloseExec fails as there
is no proper implementation for it on Windows at the moment. Workaround
this by pretending that setting close-on-exec on the fd works. This can
be done because libvirt currently lacks the ability to create child
processes on Windows anyway. So there is no point in failing to set a
flag that isn't useful at the moment anyway.

(cherry picked from commit fcfa4bfb)

After freeing the bitmap pointer, it must set the pointer to NULL.
This will avoid any other use of the freed memory of the bitmap pointer.

https://bugzilla.redhat.com/show_bug.cgi?id=1006710Signed-off-by: NLiuji (Jeremy) <jeremy.liu@huawei.com>
(cherry picked from commit ef5d51d4)

Conflicts:
	src/conf/domain_conf.c

Commit 29fe5d74 (released in 1.1.1) introduced a latent problem
for any caller of virSecurityManagerSetProcessLabel and where
the domain already had a uid:gid label to be parsed.  Such a
setup would collect the list of supplementary groups during
virSecurityManagerPreFork, but then ignores that information,
and thus fails to call setgroups() to adjust the supplementary
groups of the process.

Upstream does not use virSecurityManagerSetProcessLabel for
qemu (it uses virSecurityManagerSetChildProcessLabel instead),
so this problem remained latent until backporting the initial
commit into v0.10.2-maint (commit c061ff5e, released in 0.10.2.7),
where virSecurityManagerSetChildProcessLabel has not been
backported.  As a result of using a different code path in the
backport, attempts to start a qemu domain that runs as qemu:qemu
will end up with supplementary groups unchanged from the libvirtd
parent process, rather than the desired supplementary groups of
the qemu user.  This can lead to failure to start a domain
(typical Fedora setup assigns user 107 'qemu' to both group 107
'qemu' and group 36 'kvm', so a disk image that is only readable
under kvm group rights is locked out).  Worse, it is a security
hole (the qemu process will inherit supplemental group rights
from the parent libvirtd process, which means it has access
rights to files owned by group 0 even when such files should
not normally be visible to user qemu).

LXC does not use the DAC security driver, so it is not vulnerable
at this time.  Still, it is better to plug the latent hole on
the master branch first, before cherry-picking it to the only
vulnerable branch v0.10.2-maint.

* src/security/security_dac.c (virSecurityDACGetIds): Always populate
groups and ngroups, rather than only when no label is parsed.
Signed-off-by: NEric Blake <eblake@redhat.com>
(cherry picked from commit 745aa55f)

The virBitmapParse function was calling virBitmapIsSet() function that
requires the caller to check the bounds of the bitmap without checking
them. This resulted into crashes when parsing a bitmap string that was
exceeding the bounds used as argument.

This patch refactors the function to use virBitmapSetBit without
checking if the bit is set (this function does the checks internally)
and then counts the bits in the bitmap afterwards (instead of keeping
track while parsing the string).

This patch also changes the "parse_error" label to a more common
"error".

The refactor should also get rid of the need to call sa_assert on the
returned variable as the callpath should allow coverity to infer the
possible return values.

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=997367

Thanks to Alex Jia for tracking down the issue. This issue is introduced
by commit 0fc89098.

(cherry picked from commit 47b9127e)

Conflicts:
	src/util/bitmap.c - context, coverity fix not backported

Sometimes it's handy to know how many bits are set.

* src/util/bitmap.h (virBitmapCountBits): New prototype.
(virBitmapNextSetBit): Use correct type.
* src/util/bitmap.c (virBitmapNextSetBit): Likewise.
(virBitmapSetAll): Maintain invariant of clear tail bits.
(virBitmapCountBits): New function.
* src/libvirt_private.syms (bitmap.h): Export it.
* tests/virbitmaptest.c (test2): Test it.

(cherry picked from commit 0711c4b7)

Call virLogVMessage instead of virLogMessage, since libudev
called us with a va_list object, not a list of arguments.

Honor message priority and strip the trailing newline.

https://bugzilla.redhat.com/show_bug.cgi?id=969152
(cherry picked from commit f753dd62)

Conflicts:
	src/libvirt_private.syms
	src/node_device/node_device_udev.c
	src/util/logging.c
	src/util/logging.h

https://bugzilla.redhat.com/show_bug.cgi?id=964358

Attempts to start a domain with both SELinux and DAC security
modules loaded will deadlock; latent problem introduced in commit
fdb3bde3 and exposed in commit 29fe5d74.  Basically, when recursing
into the security manager for other driver's prefork, we have to
undo the asymmetric lock taken at the manager level.

Reported by Jiri Denemark, with diagnosis help from Dan Berrange.

* src/security/security_stack.c (virSecurityStackPreFork): Undo
extra lock grabbed during recursion.
Signed-off-by: NEric Blake <eblake@redhat.com>
(cherry picked from commit bfc183c1)

https://bugzilla.redhat.com/show_bug.cgi?id=964358

Commit 75c12564 states that virGetGroupList must not be called
between fork and exec, then commit ee777e99 promptly violated
that for lxc's use of virSecurityManagerSetProcessLabel.  Hoist
the supplemental group detection to the time that the security
manager needs to fork.  Qemu is safe, as it uses
virSecurityManagerSetChildProcessLabel which in turn uses
virCommand to determine supplemental groups.

This does not fix the fact that virSecurityManagerSetProcessLabel
calls virSecurityDACParseIds calls parseIds which eventually
calls getpwnam_r, which also violates fork/exec async-signal-safe
safety rules, but so far no one has complained of hitting
deadlock in that case.

* src/security/security_dac.c (_virSecurityDACData): Track groups
in private data.
(virSecurityDACPreFork): New function, to set them.
(virSecurityDACClose): Clean up new fields.
(virSecurityDACGetIds): Alter signature.
(virSecurityDACSetSecurityHostdevLabelHelper)
(virSecurityDACSetChardevLabel, virSecurityDACSetProcessLabel)
(virSecurityDACSetChildProcessLabel): Update callers.
Signed-off-by: NEric Blake <eblake@redhat.com>
(cherry picked from commit 29fe5d74)

Conflicts:
	src/security/security_dac.c - virSecurityDACSetSecurityUSBLabel needed similar treatment; no virSecurityDACSetChildPrcessLabel

https://bugzilla.redhat.com/show_bug.cgi?id=964358

A future patch wants the DAC security manager to be able to safely
get the supplemental group list for a given uid, but at the time
of a fork rather than during initialization so as to pick up on
live changes to the system's group database.  This patch adds the
framework, including the possibility of a pre-fork callback
failing.

For now, any driver that implements a prefork callback must be
robust against the possibility of being part of a security stack
where a later element in the chain fails prefork.  This means
that drivers cannot do any action that requires a call to postfork
for proper cleanup (no grabbing a mutex, for example).  If this
is too prohibitive in the future, we would have to switch to a
transactioning sequence, where each driver has (up to) 3 callbacks:
PreForkPrepare, PreForkCommit, and PreForkAbort, to either clean
up or commit changes made during prepare.

* src/security/security_driver.h (virSecurityDriverPreFork): New
callback.
* src/security/security_manager.h (virSecurityManagerPreFork):
Change signature.
* src/security/security_manager.c (virSecurityManagerPreFork):
Optionally call into driver, and allow returning failure.
* src/security/security_stack.c (virSecurityDriverStack):
Wrap the handler for the stack driver.
* src/qemu/qemu_process.c (qemuProcessStart): Adjust caller.
Signed-off-by: NEric Blake <eblake@redhat.com>
(cherry picked from commit fdb3bde3)

Conflicts:
	src/security/security_manager.c - context from previous backport differences

https://bugzilla.redhat.com/show_bug.cgi?id=964358

The hook scripts used by virCommand must be careful wrt
accessing any mutexes that may have been held by other
threads in the parent process. With the recent refactoring
there are 2 potential flaws lurking, which will become real
deadlock bugs once the global QEMU driver lock is removed.

Remove use of the QEMU driver lock from the hook function
by passing in the 'virQEMUDriverConfigPtr' instance directly.

Add functions to the virSecurityManager to be invoked before
and after fork, to ensure the mutex is held by the current
thread. This allows it to be safely used in the hook script
in the child process.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>
(cherry picked from commit 61b52d2e)

Conflicts:
	src/libvirt_private.syms - context
	src/qemu/qemu_process.c - no backport of qemud_driver struct rename
	src/security/security_manager.c - no backport of making the security driver self-locking; just expose the interface

https://bugzilla.redhat.com/show_bug.cgi?id=964358

POSIX states that multi-threaded apps should not use functions
that are not async-signal-safe between fork and exec, yet we
were using getpwuid_r and initgroups.  Although rare, it is
possible to hit deadlock in the child, when it tries to grab
a mutex that was already held by another thread in the parent.
I actually hit this deadlock when testing multiple domains
being started in parallel with a command hook, with the following
backtrace in the child:

 Thread 1 (Thread 0x7fd56bbf2700 (LWP 3212)):
 #0  __lll_lock_wait ()
     at ../nptl/sysdeps/unix/sysv/linux/x86_64/lowlevellock.S:136
 #1  0x00007fd5761e7388 in _L_lock_854 () from /lib64/libpthread.so.0
 #2  0x00007fd5761e7257 in __pthread_mutex_lock (mutex=0x7fd56be00360)
     at pthread_mutex_lock.c:61
 #3  0x00007fd56bbf9fc5 in _nss_files_getpwuid_r (uid=0, result=0x7fd56bbf0c70,
     buffer=0x7fd55c2a65f0 "", buflen=1024, errnop=0x7fd56bbf25b8)
     at nss_files/files-pwd.c:40
 #4  0x00007fd575aeff1d in __getpwuid_r (uid=0, resbuf=0x7fd56bbf0c70,
     buffer=0x7fd55c2a65f0 "", buflen=1024, result=0x7fd56bbf0cb0)
     at ../nss/getXXbyYY_r.c:253
 #5  0x00007fd578aebafc in virSetUIDGID (uid=0, gid=0) at util/virutil.c:1031
 #6  0x00007fd578aebf43 in virSetUIDGIDWithCaps (uid=0, gid=0, capBits=0,
     clearExistingCaps=true) at util/virutil.c:1388
 #7  0x00007fd578a9a20b in virExec (cmd=0x7fd55c231f10) at util/vircommand.c:654
 #8  0x00007fd578a9dfa2 in virCommandRunAsync (cmd=0x7fd55c231f10, pid=0x0)
     at util/vircommand.c:2247
 #9  0x00007fd578a9d74e in virCommandRun (cmd=0x7fd55c231f10, exitstatus=0x0)
     at util/vircommand.c:2100
 #10 0x00007fd56326fde5 in qemuProcessStart (conn=0x7fd53c000df0,
     driver=0x7fd55c0dc4f0, vm=0x7fd54800b100, migrateFrom=0x0, stdin_fd=-1,
     stdin_path=0x0, snapshot=0x0, vmop=VIR_NETDEV_VPORT_PROFILE_OP_CREATE,
     flags=1) at qemu/qemu_process.c:3694
 ...

The solution is to split the work of getpwuid_r/initgroups into the
unsafe portions (getgrouplist, called pre-fork) and safe portions
(setgroups, called post-fork).

* src/util/virutil.h (virSetUIDGID, virSetUIDGIDWithCaps): Adjust
signature.
* src/util/virutil.c (virSetUIDGID): Add parameters.
(virSetUIDGIDWithCaps): Adjust clients.
* src/util/vircommand.c (virExec): Likewise.
* src/util/virfile.c (virFileAccessibleAs, virFileOpenForked)
(virDirCreate): Likewise.
* src/security/security_dac.c (virSecurityDACSetProcessLabel):
Likewise.
* src/lxc/lxc_container.c (lxcContainerSetID): Likewise.
* configure.ac (AC_CHECK_FUNCS_ONCE): Check for setgroups, not
initgroups.
Signed-off-by: NEric Blake <eblake@redhat.com>
(cherry picked from commit ee777e99)

Conflicts:
	src/lxc/lxc_container.c - did not use setUIDGID before 1.1.0
	src/util/virutil.c - oom handling changes not backported; no virSetUIDGIDWithCaps
	src/util/virfile.c - functions still lived in virutil.c this far back
	configure.ac - context with previous commit
	src/util/command.c - no UID/GID handling in vircommand.c...
	src/storage/storage_backend.c - ...so do it in the one hook user instead

https://bugzilla.redhat.com/show_bug.cgi?id=964358

Since neither getpwuid_r() nor initgroups() are safe to call in
between fork and exec (they obtain a mutex, but if some other
thread in the parent also held the mutex at the time of the fork,
the child will deadlock), we have to split out the functionality
that is unsafe.  At least glibc's initgroups() uses getgrouplist
under the hood, so the ideal split is to expose getgrouplist for
use before a fork.  Gnulib already gives us a nice wrapper via
mgetgroups; we wrap it once more to look up by uid instead of name.

* bootstrap.conf (gnulib_modules): Add mgetgroups.
* src/util/virutil.h (virGetGroupList): New declaration.
* src/util/virutil.c (virGetGroupList): New function.
* src/libvirt_private.syms (virutil.h): Export it.
Signed-off-by: NEric Blake <eblake@redhat.com>
(cherry picked from commit 75c12564)

Conflicts:
	bootstrap.conf - not updating gnulib submodule...
	configure.ac - ...so checking for getgrouplist by hand...
	src/util/virutil.c - ...and copying only the getgrouplist implementation rather than calling the gnulib function; also, file still named util.c
	src/libvirt_private.syms - context

https://bugzilla.redhat.com/show_bug.cgi?id=964358

A future patch needs to look up pw_gid; but it is wasteful
to crawl through getpwuid_r twice for two separate pieces
of information, and annoying to copy that much boilerplate
code for doing the crawl.  The current internal-only
virGetUserEnt is also a rather awkward interface; it's easier
to just design it to let callers request multiple pieces of
data as needed from one traversal.

And while at it, I noticed that virGetXDGDirectory could deref
NULL if the getpwuid_r lookup fails.

* src/util/virutil.c (virGetUserEnt): Alter signature.
(virGetUserDirectory, virGetXDGDirectory, virGetUserName): Adjust
callers.
Signed-off-by: NEric Blake <eblake@redhat.com>
(cherry picked from commit c1983ba4)

Conflicts:
	src/util/virutil.c - oom reporting/strdup changes not backported

Don't reuse the return value of virStorageBackendFileSystemIsMounted.
If it's 0, we'd return it even if the mount command failed.

Also, don't report another error if it's -1, since one has already
been reported.

Introduced by 258e06c8.

https://bugzilla.redhat.com/show_bug.cgi?id=981251
(cherry picked from commit 13fde7ce)

Don't check for '\n' at the end of file if zero bytes were read.

Found by valgrind:
==404== Invalid read of size 1
==404==    at 0x529B09F: virCgroupGetValueStr (vircgroup.c:540)
==404==    by 0x529AF64: virCgroupMoveTask (vircgroup.c:1079)
==404==    by 0x1EB475: qemuSetupCgroupForEmulator (qemu_cgroup.c:1061)
==404==    by 0x1D9489: qemuProcessStart (qemu_process.c:3801)
==404==    by 0x18557E: qemuDomainObjStart (qemu_driver.c:5787)
==404==    by 0x190FA4: qemuDomainCreateWithFlags (qemu_driver.c:5839)

Introduced by 0d0b4098.

https://bugzilla.redhat.com/show_bug.cgi?id=978356
(cherry picked from commit 306c49ff)

Free the old XML strings before overwriting them if the user
has chosen to reedit the file or force the redefinition.

Found by Alex Jia trying to reproduce another bug:
https://bugzilla.redhat.com/show_bug.cgi?id=977430#c3
(cherry picked from commit 1e3a2529)