path: root/isolation.h
diff options
authorDavid Gibson <david@gibson.dropbear.id.au>2022-09-12 22:24:07 +1000
committerStefano Brivio <sbrivio@redhat.com>2022-09-13 05:31:51 +0200
commiteed17a47fe8291d449fd505d9a6b1f4a72be8d09 (patch)
treeb88d226da816c7059f704b00206fad0788898112 /isolation.h
parentd9f889a55a8bf4dc2e0caf61f35bc15dd6a68e06 (diff)
Handle userns isolation and dropping root at the same time
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>
Diffstat (limited to 'isolation.h')
1 files changed, 1 insertions, 1 deletions
diff --git a/isolation.h b/isolation.h
index 2540a35..2c73df7 100644
--- a/isolation.h
+++ b/isolation.h
@@ -8,7 +8,7 @@
void drop_caps(void);
-void drop_root(uid_t uid, gid_t gid);
+void isolate_user(uid_t uid, gid_t gid, bool use_userns, const char *userns);
int sandbox(struct ctx *c);
void seccomp(const struct ctx *c);