Commit Graph

5 Commits (f771327f0cd4bf04642b7b7171be17b242be798b)

Author SHA1 Message Date
Denton Gentry 139a6c4c9c net/dns: detect when resolvconf points to systemd-resolved.
There are /etc/resolv.conf files out there where resolvconf wrote
the file but pointed to systemd-resolved as the nameserver.
We're better off handling those as systemd-resolved.

> # Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8)
> #     DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN
> # 127.0.0.53 is the systemd-resolved stub resolver.
> # run "systemd-resolve --status" to see details about the actual nameservers.

Fixes https://github.com/tailscale/tailscale/issues/3026
Signed-off-by: Denton Gentry <dgentry@tailscale.com>
3 years ago
David Anderson a320d70614 net/dns: fall back to copy+delete/truncate if moving to/from /etc/resolv.conf fails.
In some containers, /etc/resolv.conf is a bind-mount from outside the container.
This prevents renaming to or from /etc/resolv.conf, because it's on a different
filesystem from linux's perspective. It also prevents removing /etc/resolv.conf,
because doing so would break the bind-mount.

If we find ourselves within this environment, fall back to using copy+delete when
renaming to /etc/resolv.conf, and copy+truncate when renaming from /etc/resolv.conf.

Fixes #3000

Co-authored-by: Denton Gentry <dgentry@tailscale.com>
Signed-off-by: David Anderson <danderson@tailscale.com>
3 years ago
Brad Fitzpatrick 640134421e all: update tests to use tstest.MemLogger
And give MemLogger a mutex, as one caller had, which does match the logf
contract better.

Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
3 years ago
David Anderson 10547d989d net/dns: exhaustively test DNS selection paths for linux.
Signed-off-by: David Anderson <danderson@tailscale.com>
3 years ago
Brad Fitzpatrick 065c4ffc2c net/dns: add start of Linux newOSConfigurator tests
Only one test case so far.

Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
3 years ago