Commit Graph

25 Commits

Author SHA1 Message Date
Eric Blake
c91d13bd0f build: fix build on mingw with winpthreads
On my Fedora 20 box with mingw cross-compiler, the build failed with:

../../src/rpc/virnetclient.c: In function 'virNetClientSetTLSSession':
../../src/rpc/virnetclient.c:745:14: error: unused variable 'oldmask' [-Werror=unused-variable]
     sigset_t oldmask, blockedsigs;
              ^

I traced it to the fact that mingw64-winpthreads installs a header
that does #define pthread_sigmask(...) 0, which means any argument
only ever passed to pthread_sigmask is reported as unused.  This
patch works around the compilation failure, with behavior no worse
than what mingw already gives us regarding the function being a
no-op.

* configure.ac (pthread_sigmask): Probe for broken mingw macro.
* src/util/virutil.h (pthread_sigmask): Rewrite to something that
avoids unused variables.

Signed-off-by: Eric Blake <eblake@redhat.com>
2014-01-13 09:14:11 -07:00
Daniel P. Berrange
c566fa1ad0 Add stub getegid impl for platforms lacking it
We already have stubs for getuid, geteuid, getgid but
not for getegid. Something in gnulib already does a
check for it during configure, so we already have the
HAVE_GETEGID macro defined.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
2013-10-21 14:03:52 +01:00
Daniel P. Berrange
ae53e5d10e Add helpers for getting env vars in a setuid environment
Care must be taken accessing env variables when running
setuid. Introduce a virGetEnvAllowSUID for env vars which
are safe to use in a setuid environment, and another
virGetEnvBlockSUID for vars which are not safe. Also add
a virIsSUID helper method for any other non-env var code
to use.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
2013-10-21 14:03:52 +01:00
Bing Bu Cao
19e7c04dce util: fix two virCompareLimitUlong bugs
The helper function virCompareLimitUlong compares limit values,
where value of 0 is equal to unlimited. If the latter parameter is 0,
it should return -1 instead of 1, hence the user can only set hard_limit when
swap_hard_limit currently is unlimited.

Worse, all callers pass 2 64-bit values, but on 32-bit platforms,
the second argument was silently truncated to 32 bits, which
could lead to incorrect computations.

Signed-off-by: Bing Bu Cao <mars@linux.vnet.ibm.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
2013-10-11 06:34:18 -06:00
Dan Walsh
fbd7682706 util: add virGetUserDirectoryByUID
This function is needed for virt-login-shell.  Also modify virGirUserDirectory
to use the new function, to simplify the code.

Signed-off-by: Eric Blake <eblake@redhat.com>
2013-07-30 15:25:59 -06:00
Martin Kletzander
bba579b6e0 Expose ownership ID parsing
Parsing 'user:group' is useful even outside the DAC security driver,
so expose the most abstract function which has no DAC security driver
bits in itself.
2013-07-24 14:29:11 +02:00
Eric Blake
ee777e9949 util: make virSetUIDGID async-signal-safe
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: Eric Blake <eblake@redhat.com>
2013-07-11 15:46:42 -06:00
Eric Blake
75c125641a util: add virGetGroupList
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: Eric Blake <eblake@redhat.com>
2013-07-11 15:25:53 -06:00
Osier Yang
c56c273be6 util: Change virIsCapable* to return bool
Function name with "aIsB" generally means its return value is
in Bi-state (true/false).
2013-05-13 17:17:26 +08:00
Laine Stump
bfe7721d50 util: move virFile* functions from virutil.c to virfile.c
These all existed before virfile.c was created, and for some reason
weren't moved.

This is mostly straightfoward, although the syntax rule prohibiting
write() had to be changed to have an exception for virfile.c instead
of virutil.c.

This movement pointed out that there is a function called
virBuildPath(), and another almost identical function called
virFileBuildPath(). They really should be a single function, which
I'll take care of as soon as I figure out what the arglist should look
like.
2013-05-10 13:09:30 -04:00
Daniel P. Berrange
ead630319d Separate virGetHostname() API contract from driver APIs
Currently the virGetHostname() API has a bogus virConnectPtr
parameter. This is because virtualization drivers directly
reference this API in their virDriverPtr tables, tieing its
API design to the public virConnectGetHostname API design.

This also causes problems for access control checks since
these must only be done for invocations from the public
API, not internal invocation.

Remove the bogus virConnectPtr parameter, and make each
hypervisor driver provide a dedicated function for the
driver API impl. This will allow access control checks
to be easily inserted later.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
2013-05-08 10:47:47 +01:00
Michal Privoznik
7c9a2d88cd virutil: Move string related functions to virstring.c
The source code base needs to be adapted as well. Some files
include virutil.h just for the string related functions (here,
the include is substituted to match the new file), some include
virutil.h without any need (here, the include is removed), and
some require both.
2013-05-02 16:56:55 +02:00
Peter Krempa
fa006c4fdd qemu: Fix setting of memory tunables
Refactoring done in 19c6ad9ac7 didn't
correctly take into account the order cgroup limit modification needs to
be done in. This resulted into errors when decreasing the limits.

The operations need to take place in this order:

decrease hard limit
change swap hard limit

or

change swap hard limit
increase hard limit

This patch also fixes the check if the hard_limit is less than
swap_hard_limit to print better error messages. For this purpose I
introduced a helper function virCompareLimitUlong to compare limit
values where value of 0 is equal to unlimited. Additionally the check is
now applied also when the user does not provide all of the tunables
through the API and in that case the currently set values are used.

This patch resolves:
https://bugzilla.redhat.com/show_bug.cgi?id=950478
2013-04-23 07:10:56 +02:00
Osier Yang
f5a610872a storage: Guess the parent if it's not specified for vHBA
This finds the parent for vHBA by iterating over all the HBA
which supports vport_ops capability on the host, and return
the first one which is online, not saturated (vports in use
is less than max_vports).
2013-04-08 18:41:07 +08:00
Osier Yang
b52fbad150 util: Add helper to get the scsi host name by iterating over sysfs
The helper iterates over sysfs, to find out the matched scsi host
name by comparing the wwnn,wwpn pair. It will be used by checkPool
and refreshPool of storage scsi backend. New helper getAdapterName
is introduced in storage_backend_scsi.c, which uses the new util
helper virGetFCHostNameByWWN to get the fc_host adapter name.
2013-04-08 18:41:06 +08:00
Osier Yang
5eeb56fb2a util: Fix the conflict type for virIsCapableFCHost
---
Pushed under build-breaker rule.
2013-03-28 20:17:05 +08:00
Osier Yang
96d3086a4f nodedev: Abstract nodeDeviceVportCreateDelete as util function
This abstracts nodeDeviceVportCreateDelete as an util function
virManageVport, which can be further used by later storage patches
(to support persistent vHBA, I don't want to create the vHBA
using the public API, which is not good).
2013-03-25 20:46:05 +08:00
Osier Yang
4360a09844 nodedev: Refactor the helpers
This adds two util functions (virIsCapableFCHost and virIsCapableVport),
and rename helper check_fc_host_linux as detect_scsi_host_caps,
check_capable_vport_linux is removed, as it's abstracted to the util
function virIsCapableVport. detect_scsi_host_caps nows detect both
the fc_host and vport_ops capabilities. "stat(2)" is replaced with
"access(2)" for saving.

* src/util/virutil.h:
  - Declare virIsCapableFCHost and virIsCapableVport
* src/util/virutil.c:
  - Implement virIsCapableFCHost and virIsCapableVport
* src/node_device/node_device_linux_sysfs.c:
  - Remove check_capable_vport_linux
  - Rename check_fc_host_linux as detect_scsi_host_caps, and refactor
    it a bit to detect both fc_host and vport_os capabilities
* src/node_device/node_device_driver.h:
  - Change/remove the related declarations
* src/node_device/node_device_udev.c: (Use detect_scsi_host_caps)
* src/node_device/node_device_hal.c: (Likewise)
* src/node_device/node_device_driver.c (Likewise)
2013-03-25 20:46:05 +08:00
Osier Yang
244ce462e2 util: Add one helper virReadFCHost to read the value of fc_host entry
"open_wwn_file" in node_device_linux_sysfs.c is redundant, on one
hand it duplicates work of virFileReadAll, on the other hand, it's
waste to use a function for it, as there is no other users of it.
So I don't see why the file opening work cannot be done in
"read_wwn_linux".

"read_wwn_linux" can be abstracted as an util function. As what all
it does is to read the sysfs entry.

So this patch removes "open_wwn_file", and abstract "read_wwn_linux"
as an util function "virReadFCHost" (a more general name, because
after changes, it can read each of the fc_host entry now).

* src/util/virutil.h: (Declare virReadFCHost)
* src/util/virutil.c: (Implement virReadFCHost)
* src/node_device/node_device_linux_sysfs.c: (Remove open_wwn_file,
  and read_wwn_linux)
src/node_device/node_device_driver.h: (Remove the declaration of
  read_wwn_linux, and the related macros)
src/libvirt_private.syms: (Export virReadFCHost)
2013-03-25 20:46:05 +08:00
Laine Stump
49fa91b3ee util: fix clear_emulator_capabilities=0
My commit 7a2e845a86 (and its
prerequisites) managed to effectively ignore the
clear_emulator_capabilities setting in qemu.conf (visible in the code
as the VIR_EXEC_CLEAR_CAPS flag when qemu is being exec'ed), with the
result that the capabilities are always cleared regardless of the
qemu.conf setting. This patch fixes it by passing the flag through to
virSetUIDGIDWithCaps(), which uses it to decide whether or not to
clear existing capabilities before adding in those that were
requested.

Note that the existing capabilities are *always* cleared if the new
process is going to run as non-root, since the whole point of running
non-root is to have the capabilities removed (it's still possible to
maintain individual capabilities as needed using the capBits argument
though).
2013-03-14 14:02:32 -04:00
Laine Stump
e11451f42e util: virSetUIDGIDWithCaps - change uid while keeping caps
Normally when a process' uid is changed to non-0, all the capabilities
bits are cleared, even those explicitly set with calls to
capng_update()/capng_apply() made immediately before setuid. And
*after* the process' uid has been changed, it no longer has the
necessary privileges to add capabilities back to the process.

In order to set a non-0 uid while still maintaining any capabilities
bits, it is necessary to either call capng_change_id() (which
unfortunately doesn't currently call initgroups to setup auxiliary
group membership), or to perform the small amount of calisthenics
contained in the new utility function virSetUIDGIDWithCaps().

Another very important difference between the capabilities
setting/clearing in virSetUIDGIDWithCaps() and virCommand's
virSetCapabilities() (which it will replace in the next patch) is that
the new function properly clears the capabilities bounding set, so it
will not be possible for a child process to set any new
capabilities.

A short description of what is done by virSetUIDGIDWithCaps():

1) clear all capabilities then set all those desired by the caller (in
capBits) plus CAP_SETGID, CAP_SETUID, and CAP_SETPCAP (which is needed
to change the capabilities bounding set).

2) call prctl(), telling it that we want to maintain current
capabilities across an upcoming setuid().

3) switch to the new uid/gid

4) again call prctl(), telling it we will no longer want capabilities
maintained if this process does another setuid().

5) clear the capabilities that we added to allow us to
setuid/setgid/change the bounding set (unless they were also requested
by the caller via the virCommand API).

Because the modification/maintaining of capabilities is intermingled
with setting the uid, this is necessarily done in a single function,
rather than having two independent functions.

Note that, due to the way that effective capabilities are computed (at
time of execve) for a process that has uid != 0, the *file*
capabilities of the binary being executed must also have the desired
capabilities bit(s) set (see "man 7 capabilities"). This can be done
with the "filecap" command. (e.g. "filecap /usr/bin/qemu-kvm sys_rawio").
2013-02-13 16:11:16 -05:00
John Ferlan
46b1d8cf7a Enforce return check on virAsprintf() calls
Way back when I started making changes for Coverity messages my first set
were to a bunch of CHECKED_RETURN errors.  In particular virAsprintf() had
a few callers that Coverity noted didn't check their return (although some
did check if the buffer being printed to was NULL or not).

It was suggested at the time as a further patch an ATTRIBUTE_RETURN_CHECK
should be added to virAsprintf(), see:

https://www.redhat.com/archives/libvir-list/2013-January/msg00120.html

This patch does that and fixes a few more instances not found by Coverity
that failed the check.
2013-01-30 14:42:22 -07:00
Osier Yang
278f87c4b5 qemu: set unpriv_sgio when starting domain and attaching disk
This ignores the default "filtered" if unpriv_sgio is not supported
by kernel, but for explicit request "filtered", it error out for
domain starting.
2013-01-07 21:39:06 +08:00
Osier Yang
ba72cb12fa util: Prepare helpers for unpriv_sgio setting
"virGetDeviceID" could be used across the sources, but it doesn't
relate with this series, and could be done later.

* src/util/virutil.h: (Declare virGetDeviceID, and
                       vir{Get,Set}DeviceUnprivSGIO)
* src/util/virutil.c: (Implement virGetDeviceID and
                       vir{Get,Set}DeviceUnprivSGIO)
* src/libvirt_private.syms: Export private symbols of upper helpers
2013-01-07 21:34:01 +08:00
Daniel P. Berrange
44f6ae27fe Rename util.{c,h} to virutil.{c,h} 2012-12-21 11:19:49 +00:00