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| author | Lennart Poettering <lennart@poettering.net> | 2019-05-13 15:23:47 +0200 |
|---|---|---|
| committer | Zbigniew Jędrzejewski-Szmek <zbyszek@in.waw.pl> | 2019-05-16 19:24:59 +0200 |
| commit | a305eda35f18fbacc771cc1582b688d60890a9d2 (patch) | |
| tree | fef25f13c3add1d9499199615267a42250eb7bc8 /docs/UIDS-GIDS.md | |
| parent | 8550506439add2f92bbcf556a06d11642986a79d (diff) | |
| download | systemd-a305eda35f18fbacc771cc1582b688d60890a9d2.tar.gz | |
docs: add comment about high 32bit range and signed uids
Diffstat (limited to 'docs/UIDS-GIDS.md')
| -rw-r--r-- | docs/UIDS-GIDS.md | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/docs/UIDS-GIDS.md b/docs/UIDS-GIDS.md index 25345a918f..480ee231e7 100644 --- a/docs/UIDS-GIDS.md +++ b/docs/UIDS-GIDS.md @@ -237,7 +237,8 @@ the artifacts the container manager persistently leaves in the system. | 65535 | 16bit `(uid_t) -1` | Linux | | | 65536…524287 | Unused | | | | 524288…1879048191 | Container UID ranges | `systemd` | `nss-mymachines` | -| 1879048192…4294967294 | Unused | | | +| 1879048191…2147483647 | Unused | | | +| 2147483648…4294967294 | HIC SVNT LEONES | | | | 4294967295 | 32bit `(uid_t) -1` | Linux | | Note that "Unused" in the table above doesn't meant that these ranges are @@ -246,6 +247,13 @@ pre-defined purposes between Linux, generic low-level distributions and `systemd`. There might very well be other packages that allocate from these ranges. +Note that the range 2147483648…4294967294 (i.e. 2^31…2^32-2) should be handled +with care. Various programs (including kernel file systems, see `devpts`) have +trouble with UIDs outside of the signed 32bit range, i.e any UIDs equal to or +above 2147483648. It is thus strongly recommended to stay away from this range +in order to avoid complications. This range should be considered reserved for +future, special purposes. + ## Notes on resolvability of user and group names User names, UIDs, group names and GIDs don't have to be resolvable using NSS |