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authorPaul Holzinger <pholzing@redhat.com>2023-06-23 10:25:32 +0200
committerStefano Brivio <sbrivio@redhat.com>2023-06-25 23:49:25 +0200
commit594dce66d3bbe30fa3f7ccce8b8eebb0bf3e7f2e (patch)
tree3489673c57c5c389b4c34af4bf47a3c01bf14ff8
parent5b646b9b1051c5aa41e0aeebfd9b6d5be6df614e (diff)
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isolation: keep CAP_SYS_PTRACE when required
When pasta is started from an existing userns and tries to join the netns from another process it fails to open /proc/$pid/ns/net due the missing CAP_SYS_PTRACE capability in the --netns-only case. A simple reproducer for this. First create a userns: $ unshare -r Then create a new netns inside it and try to join that netns with pasta. $ unshare -n sleep inf & $ pasta --config-net --netns /proc/$!/ns/net Signed-off-by: Paul Holzinger <pholzing@redhat.com> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
-rw-r--r--isolation.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/isolation.c b/isolation.c
index 19932bf..1866724 100644
--- a/isolation.c
+++ b/isolation.c
@@ -202,9 +202,11 @@ void isolate_initial(void)
* a mapping from UID 0, which only happens with pasta spawning a child
* from a non-init user namespace (pasta can't run as root), we need to
* retain CAP_SETFCAP too.
+ * We also need to keep CAP_SYS_PTRACE in order to join an existing netns
+ * path under /proc/$pid/ns/net which was created in the same userns.
*/
if (!ns_is_init() && !geteuid())
- keep |= BIT(CAP_SETFCAP);
+ keep |= BIT(CAP_SETFCAP) | BIT(CAP_SYS_PTRACE);
drop_caps_ep_except(keep);
}