Unconditional use of getenv is not secure in setuid env.
While not all libvirt code runs in a setuid env (since
much of it only exists inside libvirtd) this is not always
clear to developers. So make all the code paranoid, even
if it only ever runs inside libvirtd.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
FreeBSD 10 recently changed their definition of RAND_MAX, to try
and cover the fact that their evenly distributed results of rand()
really are a smaller range than a full power of 2. As a result,
I did some investigation, and learned:
1. POSIX requires random() to be evenly distributed across exactly
31 bits. glibc also guarantees this for rand(), but the two are
unrelated, and POSIX only associates RAND_MAX with rand().
Avoiding RAND_MAX altogether thus avoids a build failure on
FreeBSD 10.
2. Concatenating random bits from a PRNG will NOT provide uniform
coverage over the larger value UNLESS the period of the original
PRNG is at least as large as the number of bits being concatenated.
Simple example: suppose that RAND_MAX were 1 with a period of 2**1
(which means that the PRNG merely alternates between 0 and 1).
Concatenating two successive rand() calls would then invariably
result in 01 or 10, which is a rather non-uniform distribution
(00 and 11 are impossible) and an even worse period (2**0, since
our second attempt will get the same number as our first attempt).
But a RAND_MAX of 1 with a period of 2**2 (alternating between
0, 1, 1, 0) provides sane coverage of all four values, if properly
tempered. (Back-to-back calls would still only see half the values
if we don't do some tempering). We therefore want to guarantee a
period of at least 2**64, preferably larger (as a tempering factor);
POSIX only makes this guarantee for random() with 256 bytes of info.
* src/util/virrandom.c (virRandomBits): Use constants that are
accurate for the PRNG we are using, not an unrelated PRNG.
(randomState): Ensure the period of our PRNG exceeds our usage.
Signed-off-by: Eric Blake <eblake@redhat.com>
When virAsprintf was changed from a function to a macro
reporting OOM error in dc6f2da, it was documented as returning
0 on success. This is incorrect, it returns the number of bytes
written as asprintf does.
Some of the functions were converted to use virAsprintf's return
value directly, changing the return value on success from 0 to >= 0.
For most of these, this is not a problem, but the change in
virPCIDriverDir breaks PCI passthrough.
The return value check in virhashtest pre-dates virAsprintf OOM
conversion.
vmwareMakePath seems to be unused.
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.
https://www.gnu.org/licenses/gpl-howto.html recommends that
the 'If not, see <url>.' phrase be a separate sentence.
* tests/securityselinuxhelper.c: Remove doubled line.
* tests/securityselinuxtest.c: Likewise.
* globally: s/; If/. If/
Use of ldexp() requires -lm on some platforms; use gnulib to determine
this for our makefile. Also, optimize virRandomInt() for the case
of a power-of-two limit (actually rather common, given that Daniel
has a pending patch to replace virRandomBits(10) with code that will
default to virRandomInt(1024) on default SELinux settings).
* .gnulib: Update to latest, for ldexp.
* bootstrap.conf (gnulib_modules): Import ldexp.
* src/Makefile.am (libvirt_util_la_CFLAGS): Link with -lm when
needed.
* src/util/virrandom.c (virRandomInt): Optimize powers of 2.
The current virRandomBits() API is only usable if the caller wants
a random number in the range [0, n-1) where n is a power of two.
This adds a virRandom() API which generates a double in the
range [0.0,1.0) with 48 bits of entropy. It then also adds a
virRandomInt(uint32_t max) API which generates an unsigned
in the range [0,@max)
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
All callers used the same initialization seed (well, the new
viratomictest forgot to look at getpid()); so we might as well
make this value automatic. And while it may feel like we are
giving up functionality, I documented how to get it back in the
unlikely case that you actually need to debug with a fixed
pseudo-random sequence. I left that crippled by default, so
that a stray environment variable doesn't cause a lack of
randomness to become a security issue.
* src/util/virrandom.c (virRandomInitialize): Rename...
(virRandomOnceInit): ...and make static, with one-shot call.
Document how to do fixed-seed debugging.
* src/util/virrandom.h (virRandomInitialize): Drop prototype.
* src/libvirt_private.syms (virrandom.h): Don't export it.
* src/libvirt.c (virInitialize): Adjust caller.
* src/lxc/lxc_controller.c (main): Likewise.
* src/security/virt-aa-helper.c (main): Likewise.
* src/util/iohelper.c (main): Likewise.
* tests/seclabeltest.c (main): Likewise.
* tests/testutils.c (virtTestMain): Likewise.
* tests/viratomictest.c (mymain): Likewise.
Per the FSF address could be changed from time to time, and GNU
recommends the following now: (http://www.gnu.org/licenses/gpl-howto.html)
You should have received a copy of the GNU General Public License
along with Foobar. If not, see <http://www.gnu.org/licenses/>.
This patch removes the explicit FSF address, and uses above instead
(of course, with inserting 'Lesser' before 'General').
Except a bunch of files for security driver, all others are changed
automatically, the copyright for securify files are not complete,
that's why to do it manually:
src/security/security_selinux.h
src/security/security_driver.h
src/security/security_selinux.c
src/security/security_apparmor.h
src/security/security_apparmor.c
src/security/security_driver.c
This removes nearly all the per-file error reporting macros
from the code in src/util/. A few custom macros remain for the
case, where the file needs to report errors with a variety of
different codes or parameters
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Commit 7c90026 added #include "conf/domain_conf.h" to
util/virrandom.c. Fortunately it didn't actually use anything from
domain_conf.h, since as far as I'm aware, files in util aren't allowed
to reference anything in conf (although the opposite is allowed). So
this #include is unnecessary.
I verified it still compiles with the line removed, but have placed a
one day moratorium on me doing any "trivial rule" pushes, so will
wait for someone else to verify/ACK before pushing.
The auto-generated WWN comply with the new addressing schema of WWN:
<quote>
the first nibble is either hex 5 or 6 followed by a 3-byte vendor
identifier and 36 bits for a vendor-specified serial number.
</quote>
We choose hex 5 for the first nibble. And for the 3-bytes vendor ID,
we uses the OUI according to underlying hypervisor type, (invoking
virConnectGetType to get the virt type). e.g. If virConnectGetType
returns "QEMU", we use Qumranet's OUI (00:1A:4A), if returns
ESX|VMWARE, we use VMWARE's OUI (00:05:69). Currently it only
supports qemu|xen|libxl|xenapi|hyperv|esx|vmware drivers. The last
36 bits are auto-generated.
On RHEL5, I got:
util/virrandom.c:66: warning: nested extern declaration of '_gl_verify_function66' [-Wnested-externs]
The fix is to hoist the verify earlier. Also some other hodge-podge
fixes I noticed while reviewing Dan's recent series.
* .gitignore: Ignore new test.
* src/util/cgroup.c: Bump copyright year.
* src/util/virhash.c: Fix typo in description.
* src/util/virrandom.c (virRandomBits): Mark doc comment, and
hoist assert to silence older gcc.
The old virRandom() API was not generating good random numbers.
Replace it with a new API virRandomBits which instead of being
told the upper limit, gets told the number of bits of randomness
required.
* src/util/virrandom.c, src/util/virrandom.h: Add virRandomBits,
and move virRandomInitialize
* src/util/util.h, src/util/util.c: Delete virRandom and
virRandomInitialize
* src/libvirt.c, src/security/security_selinux.c,
src/test/test_driver.c, src/util/iohelper.c: Update for
changes from virRandom to virRandomBits
* src/storage/storage_backend_iscsi.c: Remove bogus call
to virRandomInitialize & convert to virRandomBits
