| 2 Dec 2025 |
 Randy Eckenrode | Allowing communication between derivations seems problematic. Can’t Postgres just include a sandbox profile with what it needs? | 18:36:13 |
| Randy Eckenrode | Just went and checked the CVEs from earlier. Those were about being able to inject into a build. This seems more like everybody being able to interfere with each other like if they had access to localhost. | 18:43:59 |
| Randy Eckenrode | Does upstream Nix tie it to whether local networking is allowed? | 18:44:18 |
| Randy Eckenrode | The upstream Nix patch just seems to be about cleaning up IPC objects. | 18:47:20 |
 WeetHet | Using relaxed is weird | 18:49:09 |
| WeetHet | I'm gonna put it behind __darwinAllowSysvIPC | 18:49:56 |
| WeetHet | * I'm gonna put it behind __darwinAllowSysVIPC | 18:56:20 |
 emily | please don't | 19:08:40 |
| emily | it's a misfeature that shouldn't have been added to the Nix sandbox profile | 19:08:54 |
| emily | please see https://git.lix.systems/lix-project/lix/issues/623 | 19:09:08 |
| emily | you can use a sandboxProfile, but better would be to fix Postgres to not need ye olde SysV IPC | 19:09:25 |
| emily | there is some linked discussion on the mailing list | 19:09:28 |
| emily | see also https://github.com/NixOS/nixpkgs/pull/431202#issuecomment-3193168883 linked from there | 19:10:13 |
| WeetHet | Redacted or Malformed Event | 19:11:16 |
| WeetHet | * Doesn't __darwinAllowLocalNetworking already allow that anyways? | 19:11:48 |
| WeetHet | __darwinAllowLocalNetworking also allows almost unrestricted communications, no? | 19:13:41 |
| emily | pf has enough juice to make that solvable in principle | 19:14:05 |
| emily | could not find anything that would let you do that with SysV IPC | 19:14:17 |
| emily | afaik it is basically only Postgres that needs this and they are open to fixes for that | 19:14:35 |
| WeetHet | postgres can build with POSIX semaphores, they just don't do that bc they need an FD per every semaphore | 19:15:08 |
| WeetHet | I guess a better option would be to add a postgres with posix semaphores to nixpkgs and just use that in tests | 19:15:43 |
| emily | see https://www.postgresql.org/message-id/flat/a90b5411-705f-4286-bd81-a26c520a6cfb%40technowledgy.de | 19:26:06 |
 niklaskorz | wow just when I found this through the postgres archive search you post the direct link... 😂 | 19:29:38 |
| emily | it's linked in the Lix issue I linked :) | 19:30:07 |
| niklaskorz | well at least I now know there is a postgres archive search | 19:30:43 |
| WeetHet | Is there an alternative to sysv shared memory on macOS? | 19:32:30 |
| WeetHet | There's POSIX but it's much more limited | 19:32:47 |
| WeetHet | And postgres is using SysV on Linux as well | 19:33:02 |
| Randy Eckenrode | The reply in the linked issue suggested Darwin futexes. | 19:33:23 |
| Randy Eckenrode | * | 19:33:31 |
