path: root/pasta.h
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* Handle userns isolation and dropping root at the same timeDavid Gibson2022-09-131-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | passt/pasta can interact with user namespaces in a number of ways: 1) With --netns-only we'll remain in our original user namespace 2) With --userns or a PID option to pasta we'll join either the given user namespace or that of the PID 3) When pasta spawns a shell or command we'll start a new user namespace for the command and then join it 4) With passt we'll create a new user namespace when we sandbox() ourself However (3) and (4) turn out to have essentially the same effect. In both cases we create one new user namespace. The spawned command starts there, and passt/pasta itself will live there from sandbox() onwards. Because of this, we can simplify user namespace handling by moving the userns handling earlier, to the same point we drop root in the original namespace. Extend the drop_user() function to isolate_user() which does both. After switching UID and GID in the original userns, isolate_user() will either join or create the userns we require. When we spawn a command with pasta_start_ns()/pasta_setup_ns() we no longer need to create a userns, because we're already made one. sandbox() likewise no longer needs to create (or join) an userns because we're already in the one we need. We no longer need c->pasta_userns_fd, since the fd is only used locally in isolate_user(). Likewise we can replace c->netns_only with a local in conf(), since it's not used outside there. Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
* Clean up and rename conf_ns_open()David Gibson2022-09-131-0/+1
| | | | | | | | | | | | | | conf_ns_open() opens file descriptors for the namespaces pasta needs, but it doesnt really have anything to do with configuration any more. For better clarity, move it to pasta.c and rename it pasta_open_ns(). This makes the symmetry between it and pasta_start_ns() more clear, since these represent the two basic ways that pasta can operate, either attaching to an existing namespace/process or spawning a new one. Since its no longer validating options, the errors it could return shouldn't cause a usage message. Just exit directly with an error instead. Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
* Allow pasta to take a command to executeDavid Gibson2022-08-301-1/+1
| | | | | | | | | | | | | | When not given an existing PID or network namspace to attach to, pasta spawns a shell. Most commands which can spawn a shell in an altered environment can also run other commands in that same environment, which can be useful in automation. Allow pasta to do the same thing; it can be given an arbitrary command to run in the network and user namespace which pasta creates. If neither a command nor an existing PID or netns to attach to is given, continue to spawn a default shell, as before. Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
* treewide: Add include guardsStefano Brivio2022-03-291-0/+5
| | | | | | | ...at the moment, just for consistency with packet.h, icmp.h, tcp.h and udp.h. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* pasta: By default, quit if filesystem-bound net namespace goes awayStefano Brivio2022-02-211-0/+2
| | | | | | | | | | | | This should be convenient for users managing filesystem-bound network namespaces: monitor the base directory of the namespace and exit if the namespace given as PATH or NAME target is deleted. We can't add an inotify watch directly on the namespace directory, that won't work with nsfs. Add an option to disable this behaviour, --no-netns-quit. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* LICENSES: Add license text files, add missing notices, fix SPDX tagsStefano Brivio2021-10-201-0/+5
| | | | | | | | | | SPDX tags don't replace license files. Some notices were missing and some tags were not according to the SPDX specification, too. Now reuse --lint from the REUSE tool (https://reuse.software/) passes. Reported-by: Martin Hauke <mardnh@gmx.de> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
* pasta: Push pasta.h headerStefano Brivio2021-10-141-0/+3
...I forgot to add this earlier. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>