dbus binding doesn't detect values with incorrect types in arrays, it elides them

[trgill]

For example, the following uses an incorrect a(sss), but the call gets through...

busctl --user call org.storage.stratis1 /org/storage/stratis1/1 org.storage.stratis1.pool CreateFilesystems a(sss) 3 volume1 /dev/mount/point 10 volume2 /dev/mount/point2 11 volume3 /dev/mount/point3 12
a(oqs)qs 00 "Ok"

It doesn't seem to be a big deal - the filesystems array is 0 length.

[mulkieran]

I'm guessing that busctl never sends the actual signature over the dbus, just the values, packaged according to the signature information you gave it. I bet stratisd would have an issue if one of those numbers were negative, or otherwise didn't fit the uint64 requirements.

[agrover]

OK, what happens when one of the numbers is negative?

[mulkieran]

Whoops, pretty funky.

[mulhern@dhcp-25-209 stratisd]$ busctl --user call org.storage.stratis1 /org/storage/stratis1/1 org.storage.stratis1.pool CreateFilesystems "a(sss)" 1 volume1 /dev/mount/point str
a(oqs)qs 00 "Ok"

I can't get the same effect unless it's a value in array. Might be a dbus-rs problem, since we seem to be using the correct types.

[mulkieran]

Known dbus-rs bug, looks like: diwic/dbus-rs#62. There may be a work around.

[mulkieran]

All our changes to D-Bus layer haven't removed this problem, alas. What's slightly wierder is that:

[root@localhost stratisd]# busctl --system call org.storage.stratis1 /org/storage/stratis1 org.storage.stratis1.Manager CreatePool "s(bq)ban" name1 0 0 0 1 2

succeeds, but doesn't return the object path for the blockdev, which was passed as a numeric value.

(oao)qs "/org/storage/stratis1/3" 0 0 "Ok"

There's a real possibility that dbus-rs is just skipping the value that was incorrectly packaged. After all, this

[root@localhost stratisd]# busctl --system call org.storage.stratis1 /org/storage/stratis1 org.storage.stratis1.Manager CreatePool "s(bq)bas" name2 0 0 0 1 2
(oao)qs "/org/storage/stratis1/4" 1 "/org/storage/stratis1/5" 0 "Ok"

works. Not clear what to do about this, though.

[mulkieran]

We will document that this is an allowed bug in the README.