View Issue Details
| ID | Project | Category | View Status | Date Submitted | Last Update |
|---|---|---|---|---|---|
| 0001987 | unreal | ircd | public | 2004-07-22 08:47 | 2004-07-22 17:19 |
| Reporter | slePP | Assigned To | syzop | ||
| Priority | normal | Severity | minor | Reproducibility | always |
| Status | closed | Resolution | open | ||
| Product Version | 3.2-RC2 | ||||
| Summary | 0001987: [patch] Reverse DNS -> Name -> IP using T_ANY does not work properly with dnscache | ||||
| Description | When using djbdns' dnscache (perhaps others), when placing a query for T_ANY to it, it will respond with nothing but information it knows to be authoritative. Notably, this is the list of name servers for a zone, and perhaps not even that sometimes. This bug only happens when INET6 is enabled at compile time, as it changes a number of DNS queries to use T_ANY instead of more specific items. This patch adds two new functions to res.c which are only used when a PTR response has been received from a server. It then looks at the IP type it was asking for (IPv6 or IPv4) and calls the resolver routines (do_revquery_name and gethost_byname_revquery) with a flag telling them if it is IPv4 or IPv6 it should be looking for. It will then only look for a name -> IPv6 or name -> IPv4 mapping if the original reverse DNS lookup was IPv6 or IPv4 respectively. This patch is now in use on 4 servers on irc.spod.ca, if anyone cares to test it out on a live network. Until these changes were made, no reverse DNS worked at all for any of the connections. | ||||
| Steps To Reproduce | 1. Install djbdns' dnscache. 2. Make Unreal use it as a name server. 3. Connect. You'll get nothing. 4. Apply patch. 5. Recompile, restart. 6. Connect. You'll get reverse DNS on both IPv6 and IPv4 depending on connect method. | ||||
| Additional Information | [patch for issue in 0001252 {dup]] | ||||
| Attached Files | unreal32rc2-dns-revquery.patch (3,453 bytes) | ||||
| 3rd party modules | |||||
|
|
I know this isn't against the latest releases, but I do think this is a rather latent bug. Systems using BIND as a name server will work fine with or without this patch, since BIND returns a lot of information as an authority when it should not. This patch is also available at http://www.spod.ca/patches/unreal32rc2-dns-revquery.patch This patch also makes no changes to the existing do_query_name and gethost_byname functions to remain completely compatible. |
|
|
I think this is the more proper way to do IPv6 reverse lookups, imho, we should think about applying this. |
|
|
I agree. Hehe. Using T_ANY is kind of hackish, since it returns absolutely everything, increasing DNS load and traffic when it really isn't needed. What we're truly looking for on a ip -> name -> ip map is that they are connecting from a host with the same ip as their reverse name. Looking up anything else _but_ the type they're connected from just opens us up for more problems. |
|
|
Thanks! This is the patch for 0001252, I'll certainly take a look at it when I got some time (=soon). |
|
|
Thanks, fixed in CVS [.109]. If you have any questions, feel free to contact me directly at [email protected] |
| Date Modified | Username | Field | Change |
|---|---|---|---|
| 2004-07-22 08:47 | slePP | New Issue | |
| 2004-07-22 08:47 | slePP | File Added: unreal32rc2-dns-revquery.patch | |
| 2004-07-22 08:50 | slePP | Note Added: 0007208 | |
| 2004-07-22 08:53 |
|
Note Added: 0007209 | |
| 2004-07-22 08:54 | slePP | Note Added: 0007210 | |
| 2004-07-22 10:32 | syzop | Note Added: 0007211 | |
| 2004-07-22 10:34 | syzop | Assigned To | => syzop |
| 2004-07-22 10:34 | syzop | Status | new => acknowledged |
| 2004-07-22 10:34 | syzop | ETA | none => < 1 week |
| 2004-07-22 10:34 | syzop | Additional Information Updated | |
| 2004-07-22 17:19 | syzop | Status | acknowledged => closed |
| 2004-07-22 17:19 | syzop | Note Added: 0007221 |
