[libvirt PATCH] util: add access check for hooks to fix running as non-root

[Daniel Henrique Barboza]

On 7/1/20 1:39 PM, Daniel P. Berrangé wrote:
> Since feb83c1e710b9ea8044a89346f4868d03b31b0f1 libvirtd will abort on
> startup if run as non-root
> 
>    2020-07-01 16:30:30.738+0000: 1647444: error : virDirOpenInternal:2869 : cannot open directory '/etc/libvirt/hooks/daemon.d': Permission denied
> 
> The root cause flaw is that non-root libvirtd is using /etc/libvirt for
> its hooks. Traditionally that has been harmless though since we checked
> whether we could access the hook file and degraded gracefully. We need
> the same access check for iterating over the hook directory.
> 
> Long term we should make it possible to have an unprivileged hook dir
> under $HOME.
> 
> Signed-off-by: Daniel P. Berrangé <berrange at redhat.com>
> ---


This failed syntax-check:


../src/util/virhook.c:175:    if (access(dir_path, X_OK | R_OK) < 0) {
../src/util/virhook.c:425:    if (access(dir_path, X_OK | R_OK) < 0)
build-aux/syntax-check.mk: use virFileIsExecutable instead of access(,X_OK)
make: *** [../build-aux/syntax-check.mk:400: sc_prohibit_access_xok] Error 1
make: *** Waiting for unfinished jobs....


Given that this didn't break any tests and I believe we want this for the
upcoming release, feel free to change it to make 'syntax-check' happy and
add my r-b:


Reviewed-by: Daniel Henrique Barboza <danielhb413 at gmail.com>