On 05/24/2017 10:38 AM, Michal Privoznik wrote:
On 05/11/2017 05:04 PM, John Ferlan wrote:
https://bugzilla.redhat.com/show_bug.cgi?id=1374126
Due to how the processing for authentication using polkit works, the virshConnect code must first "attempt" an virConnectOpenAuth and then check for a "special" return error code VIR_ERR_AUTH_UNAVAILABLE in order to attempt to "retry" the authentication after performing a creation of a pkttyagent to handle the challenge/response for the client.
However, attempting to use a remote connection, (such as perhaps "qemu+ssh://someuser@localhost/system"), will cause a never ending loop since attempting to generate a pkttyagent would fail for the network client connection resulting in a never ending loop since the return code is always VIR_ERR_AUTH_UNAVAILABLE from virPolkitCheckAuth. The only way out of the loop is a forced quit (e.g. ctrl-c) as the @authfail wouldn't be incremented as a result of a failed authn from pkttyagent.
So rather than take any extra step for which the only result will be a failure, let's check if there is a URI and if it's not using ":///", then just fail.
This resolves the never ending loop and will generate an error:
error: failed to connect to the hypervisor error: authentication unavailable: no polkit agent available to authenticate action 'org.libvirt.unix.manage'
NB: If the authentication was for a sufficiently privileged client, such as qemu+ssh://root@localhost/system, then the remoteDispatchAuthList "allows" the authentication to use libvirt since @callerUid would be 0.
Signed-off-by: John Ferlan <jferlan@redhat.com> --- tools/virsh.c | 5 +++++ 1 file changed, 5 insertions(+)
diff --git a/tools/virsh.c b/tools/virsh.c index 1f5c2b1..be368ba 100644 --- a/tools/virsh.c +++ b/tools/virsh.c @@ -166,6 +166,11 @@ virshConnect(vshControl *ctl, const char *uri, bool readonly) if (readonly) goto cleanup;
+ /* No URI or indication of a requesting a remote connection, then + * polkit will not work for the authentication/authorization */ + if (!uri || !(strstr(uri, ":///"))) + goto cleanup;
But we can get here even without polkit, right? Therefore it'd be much more safer to check err && err->domain == VIR_FROM_POLKIT.
True - that's simple enough to adjust... So instead of: err = virGetLastError(); if (err && err->domain == VIR_FROM_POLKIT && err->code == VIR_ERR_AUTH_UNAVAILABLE) { if (!pkagent && !(pkagent = virPolkitAgentCreate())) goto cleanup; } else if (err && err->domain == VIR_FROM_POLKIT && err->code == VIR_ERR_AUTH_FAILED) { authfail++; } else { goto cleanup; } I could have if (err && err->domain == VIR_FROM_POLKIT) { /* No URI or indication of a requesting a remote connection, then * polkit will not work for the authentication/authorization */ if (!uri || !(strstr(uri, ":///"))) goto cleanup; if (err->code == VIR_ERR_AUTH_UNAVAILABLE) { if (!pkagent && !(pkagent = virPolkitAgentCreate())) goto cleanup; } else if (err->code == VIR_ERR_AUTH_FAILED) { authfail++; } else { goto cleanup; } } else { goto cleanup; } So is there a preferred approach? See the cover letter... Tks - John