On 03/13/2013 01:37 PM, Laine Stump wrote:
> My commit 7a2e845a865dc7fa82d2393ea2a770cfc8cf00b4 (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
> add back individual capabilities as needed though).
> ---
> This will need to be backported to v1.0.3-maint.
Yeah, now that Fedora 19 has branched and settled on 1.0.3 as its
starting point, it looks like v1.0.3-maint will be getting lots of fixes :)
> + if (virSetUIDGIDWithCaps(cmd->uid, cmd->gid, cmd->capabilities,
> + (cmd->flags & VIR_EXEC_CLEAR_CAPS)) < 0) {
While gnulib guarantees that we have <stdbool.h>, it also states that we
cannot rely on C99 rules for slamming random integers into 1 when
converting into a bool context (especially true for C89 compilers using
gnulib's emulation, but apparently there are also buggy C99 compilers
that miscompile things). This should use '(cmd->flags &
VIR_EXEC_CLEAR_CAPS) != 0' (or !! if you don't like != 0), just to be safe.
> + /* First drop all caps (unless the requested uid is "unchanged" or
> + * root and clearExistingCaps wasn't requested), then add back
> + * those in capBits + the extra ones we need to change uid/gid and
> + * change the capabilities bounding set.
> */
>
> - capng_clear(CAPNG_SELECT_BOTH);
> + if (clearExistingCaps || (uid != 1 && uid != 0))
Did you mean uid != 0?
ACK with those problems addressed.
--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
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