Re: [libvirt] [PATCH] util: fix clear_emulator_capabilities=0

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.

+ if (virSetUIDGIDWithCaps(cmd->uid, cmd->gid, cmd->capabilities, + (cmd->flags & VIR_EXEC_CLEAR_CAPS)) < 0) {

+ /* 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))