Crash in timsieved's cmd_authenticate() on 2.4.6

[Florian Pflug]

Hi Greg,

On Jan12, 2011, at 03:32 , Greg Banks wrote:
> On 12/01/11 02:21, Florian Pflug wrote:
>> I've just found a bug in timsieved's cmd_authenticate on cyrus 2.4.6.
>> 
>> If the authenticating user is an admin, we proceed even if the mailbox
>> lookup fails. In this case, the mboxlist_lookup seems to leave the
>> mboxlist_entry uninitialized, making the code believe that the mailbox
>> is remote if the bit MBTYPE_REMOTE happens to be set in mbentry.mvtype.
>> The crash then happens when xstrdup tried to copy mbentry.partition.
>> 
>> Initializing mbentry to zero in cmd_authenticate() fixes the bug and
>> allows admins without mailboxes (like root) to authenticate again
>> on my system.
> 
> Thanks, your analysis is correct, but I think a better fix might be the attached (untested) patch.
> 
> Bron changed the mboxlist_lookup() API very recently (not yet in a release), which means that patch won't apply to ToT, but the bug is still there.  As coincidentally I touched that code yesterday, I'll fix it.

I've just upgraded to cyrus 2.4.8, and it seems that the bug is still there.

Or at least I can set neither mine nor your patch in timsieved/parser.c - 
in fact, parser.c seems to have hardly changed since 2.4.0 at all.

# git diff cyrus-imapd-2.4.0..cyrus-imapd-2.4.8 timsieved/parser.c
diff --git a/timsieved/parser.c b/timsieved/parser.c
index dd8aaa6..731ce99 100644
--- a/timsieved/parser.c
+++ b/timsieved/parser.c
@@ -444,6 +444,9 @@ int parser(struct protstream *sieved_out, struct protstream *sieved_in)
       goto error;
     }
 
+    /* XXX  discard any input pipelined after STARTTLS */
+    prot_flush(sieved_in);
+
     if(referral_host)
        goto do_referral;

best regards,
Florian Pflug